We have recently demonstrated that TRB3, a novel endoplasmic reticulum (ER) stress-inducible protein, is induced by CHOP and ATF4 to regulate their function and ER stress-induced cell death; however, the regulation of TRB3 function has not been well characterized. Here we demonstrate that TRB3 is an unstable protein regulated by the ubiquitin-proteasome system. The carboxyl-terminal domain of TRB3 is necessary for protein degradation, and in this region, we found the typical D-box motif, which is a critical sequence for the anaphase-promoting complex/cyclosome (APC/C) dependent proteolysis. TRB3 proteins were stabilized by deletion of its D-box motif and interacted with APC/C coactivator proteins, Cdc20 and Cdh1. The expression level of TRB3 protein is down-regulated by over-expression of Cdh1 but not by that of Cdc20. In addition, knockdown of Cdh1 enhanced the endogenous TRB3 expression level and suppressed its ubiquitination level. These results suggest that APC/C(Cdh1) is involved in ubiquitination and down-regulating the stability of TRB3 protein.

Osteosarcoma is the most common primary malignant bone tumor in childhood and adolescence and has a propensity for local invasion and early lung metastasis. However, the current therapies often result in chemoresistance, and a therapeutic target is not available in the clinic for osteosarcoma. Here, we report that BRD7 forms a complex with the anaphase-promoting complex/cyclosome (APC/C) and is degraded by APC/C(cdh1) and APC/C(cdc20) during the cell cycle. Moreover, BRD7 is a tumor suppressor in osteosarcoma, and the BRD7 mutant resistant to degradation by APC/C is more efficient than the wild-type protein at suppressing proliferation, colony formation, and tumor growth of osteosarcoma in vitro and in vivo. The combination of proTAME, an inhibitor of APC/C, with chemotherapeutic drugs efficiently targets osteosarcoma in vitro. Furthermore, there is a strong inverse correlation of protein levels between BRD7 and Cdh1 or Cdc20, and lower BRD7 expression is an indicator for poor prognosis in patients with osteosarcoma. Collectively, our results indicate that targeting the APC/C-BRD7 pathway may be a novel strategy for treating osteosarcoma.

Centrosome amplification has been extensively associated with cancer. Cancer cells with extra centrosomes have the ability to cluster the extra centrosomes and divide in a bipolar fashion. Although a number of proteins have been shown to be involved in centrosome clustering, a mechanistic understanding of how this process is coordinated is not yet well defined. Here, to reveal regulators of centrosome clustering, we perform small interfering RNA (siRNA) screens with multiple assay readouts in a human isogenic cellular model. We find that APC/C activity is essential for centrosome clustering. We show that the motor kinesin Eg5 is a substrate of APC/C-CDH1, and that inhibition of APC/C results in stabilization of Eg5. Increased Eg5 protein levels disturb the balance of forces on the spindle and prevent centrosome clustering. This process is completely reversed after a short treatment with the Eg5 inhibitor, monastrol. These data advance our understanding of the regulation of centrosome clustering.

Uncontrolled cell growth and tissue invasion define the characteristic features of cancer. Several growth factors regulate these processes by inducing specific signaling pathways. We show that FGF16, a novel factor, is expressed in human ovary, and its expression is markedly increased in ovarian tumors. This finding indicated possible involvement of FGF16 in ovarian cancer progression. We observed that FGF16 stimulates the proliferation of human ovarian adenocarcinoma cells, SKOV-3 and OAW-42. Furthermore, through the activation of FGF receptor-mediated intracellular MAPK pathway, FGF16 regulates the expression of MMP2, MMP9, SNAI1, and CDH1 and thus facilitates cellular invasion. Inhibition of FGFR as well as MAPK pathway reduces the proliferative and invasive behavior of ovarian cancer cells. Moreover, ovarian tumors with up-regulated PITX2 expression also showed activation of Wnt/β-catenin pathway that prompted us to investigate possible interaction among FGF16, PITX2, and Wnt pathway. We identified that PITX2 homeodomain transcription factor interacts with and regulates FGF16 expression. Furthermore, activation of the Wnt/β-catenin pathway induces FGF16 expression. Moreover, FGF16 promoter possesses the binding elements of PITX2 as well as T-cell factor (Wnt-responsive), in close proximity, where PITX2 and β-catenin binds to and synergistically activates the same. A detail study showed that both PITX2 and T-cell factor elements and the interaction with their binding partners are necessary for target gene expression. Taken together, our findings indicate that FGF16 in conjunction with Wnt pathway contributes to the cancer phenotype of ovarian cells and suggests that modulation of its expression in ovarian cells might be a promising therapeutic strategy for the treatment of invasive ovarian cancers.

BACKGROUND

CTCs are a promising alternative for metastatic tissue biopsies for use in precision medicine approaches. We investigated to what extent the molecular characteristics of circulating tumor cells (CTCs) resemble the liver metastasis and/or the primary tumor from patients with metastatic colorectal cancer (mCRC).

RESULTS

The CTC profiles were concordant with the liver metastasis in 17/23 patients (74%) and with the primary tumor in 13 patients (57%). The CTCs better resembled the liver metastasis in 13 patients (57%), and the primary tumor in five patients (22%). The strength of the correlations was not associated with clinical parameters. Nine genes (<em>CDH1</em>, <em>CDH1</em>7, CDX1, CEACAM5, FABP1, FCGBP, IGFBP3, IGFBP4, and MAPT) displayed significant differential expressions, all of which were downregulated, in CTCs compared to the tissues in the 23 patients.

METHODS

Patients were retrospectively selected from a prospective study. Using the CellSearch System, CTCs were enumerated and isolated just prior to liver metastasectomy. A panel of 25 CTC-specific genes was measured by RT-qPCR in matching CTCs, primary tumors, and liver metastases. Spearman correlation coefficients were calculated and considered as continuous variables with r=1 representing absolute concordance and r=-1 representing absolute discordance. A cut-off of r>0.1 was applied in order to consider profiles to be concordant.

CONCLUSIONS

In the majority of the patients, CTCs reflected the molecular characteristics of metastatic cells better than the primary tumors. Genes involved in cell adhesion and epithelial-to-mesenchymal transition were downregulated in the CTCs. Our results support the use of CTC characterization as a liquid biopsy for precision medicine.

Fibrolamellar carcinomas have a unique predilection for younger individuals and arise in livers without recognizable liver disease. In contrast to typical hepatocellular carcinomas, fibrolamellar carcinomas show few chromosomal changes and lack mutation in key genes such as TP53 and CTNNB1. Epigenetic instability, manifesting as methylation of important tumor suppressor gene promoters, has not been investigated in fibrolamellar carcinomas. Thus, the methylation status of 11 tumor suppressor gene promoters was investigated using methylation-specific PCR: RASSF1, CDH1, CDKN2B, HPP1, CDKN2A, GSTP1, P16, RARA, FLJ13081, SOCS1, and TP53. Nine fibrolamellar carcinomas were studied including primary tumors (N=5) and metastatic deposits (N=4) along with control groups of typical hepatocellular carcinoma arising in livers with (N=21) and without cirrhosis (N=10). In fibrolamellar carcinomas, RASSF1A and CDH1 (e-cadherin) were the most commonly methylated genes with 80-100% of tumors methylated. However, overall fibrolamellar carcinomas showed low levels of methylation with no differences between fibrolamellar carcinomas and their paired normal livers. However, fibrolamellar carcinomas showed significantly less methylation than hepatocellular carcinomas that arose in the background of viral cirrhosis. Overall, methylation was most strongly linked to viral cirrhosis. In conclusion, fibrolamellar carcinoma shows low levels of methylation. In contrast, higher levels of promoter methylation are associated with hepatocellular carcinomas that arise in the setting of viral induced cirrhosis.

The widely expressed transcriptional coregulator, ligand-dependent corepressor (LCoR), initially characterized as a regulator of nuclear receptor-mediated transactivation, functions through recruitment of C-terminal binding proteins (CtBPs) and histone deacetylases (HDACs) to its N-terminal and central domains, respectively. We performed a yeast two-hybrid screen for novel cofactors, and identified an interaction between the C-terminal domain of LCoR and the transcription factor Krüppel-like factor 6 (KLF6), a putative tumor suppressor in prostate cancer. Subsequent experiments revealed LCoR regulation of several KLF6 target genes notably p21(WAF1/CIP1) (CDKN1A) and to a lesser extent E-cadherin (CDH1), indicating that LCoR regulates gene transcription through multiple classes of transcription factors. In multiple cancer cells, LCoR and KLF6 bind together on the promoters of the genes encoding CDKN1A and CDH1. LCoR contributes to KLF6-mediated transcriptional repression in a promoter- and cell type-dependent manner. Its inhibition of reporter constructs driven by the CDKN1A and CDH1 promoters in PC-3 prostate carcinoma cells is sensitive to treatment with the HDAC inhibitor trichostatin A. Additionally, the LCoR cofactor CtBP1 bound the same promoters and augmented the LCoR-dependent repression in PC-3 cells. Consistent with their inferred roles in transcriptional repression, siRNA-mediated knockdown of KLF6, LCoR, or CtBP1 in PC-3 cells induced expression of CDKN1A and CDH1 and additional KLF6 target genes. We propose a novel model of LCoR function in which promoter-bound KLF6 inhibits transcription of the CDKN1A gene and other genes as well by tethering a transcriptional corepressor complex containing LCoR, with specific contributions by CtBP1 and HDACs.

Triple-negative breast cancer (TNBC) remains a poor prognostic factor for breast cancer since no effective targeted therapy is readily available. Our previous studies confirmed miR-199a-5p is a TNBC-specific circulating biomarker, however, its functional roles in breast cancer is largely unknown. Thus, we investigated the functional implication of miR-199a-5p in TNBC and its potential underlying mechanisms.

MTT assay was performed to investigate the cell proliferation after transient transfection of miR-199a-5p in MDA-MB-231 cell line, followed by cell cycle analysis. Transwell invasion assay and wound healing assay were used to study the invasion and migration ability respectively. To further investigate the stemness-related characteristics of miR-199a-5p in breast cancer cells, single-cell clonogenic assay and aldehyde dehydrogenase (ALDH) assay were performed. 32 normal and 100 breast cancer patients' plasma were recruited to identify the potential circulating markers by qPCR.

Cell proliferation assay revealed significant inhibition after miR-199a-5p ectopic expression (p < 0.0001), as a result of decreased S phase (p = 0.0284), increased G0/G1 phase (p = 0.0260) and apoptosis (p = 0.0374). Invasiveness (p = 0.0005) and wound healing ability were also decreased upon miR-199a-5p overexpression. It significantly altered EMT-related genes expression, namely CDH1, ZEB1 and TWIST. Single-cell clonogenic assay showed decreased colonies in miR-199a-5p (p = 0.0182). Significant downregulation (p = 0.0088) and inhibited activity (p = 0.0390) of ALDH was observed in miR-199a-5p. ALDH1A3, which is the dominant isoform of ALDH, is significantly upregulated in breast cancer plasma especially in TNBC (p = 0.0248). PIK3CD was identified as a potential downstream target of miR-199a-5p.

Taken together, we unraveled, for the first time, the tumor-suppressive role of miR-199a-5p in TNBC, which attributed to EMT and cancer stemness properties, providing a novel therapeutic options towards this aggressive disease.

In 1998, Guilford et al. identified the hereditary diffuse gastric cancer (HDGC) syndrome, caused by germline alterations at the CDH1 (E-cadherin) gene. To date, 141 probands harboring more than 100 different germline CDH1 alterations, mainly point mutations and large deletions, have been described. In mutation-positive individuals prophylactic total gastrectomy is recommended. The systematic histological study of prophylactic gastrectomies shows intramucosal signet-ring cell carcinoma and pre-invasive lesions including in situ signet ring carcinoma with pagetoid spread of signet ring cells. In 2011, a new hereditary gastric cancer syndrome was identified: gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS). GAPPS is a unique gastric polyposis syndrome with a significant risk of gastric adenocarcinoma, characterized by the autosomal dominant transmission of fundic gland polyposis, with areas of dysplasia or intestinal-type GC, restricted to the proximal stomach, with no evidence of colorectal or duodenal polyposis or other heritable gastrointestinal cancer syndromes.

Somatic mutations in the E-cadherin (CDH1) gene have frequently been reported in cases with diffuse gastric and lobular breast cancers. Recently, germline mutations have been identified in families with diffuse gastric cancers. In families with hereditary prostate cancer (HPC), a significant association of prostate cancer, gastric and/or breast cancer has been observed in epidemiological studies. The aim of this study was to investigate if germline mutations in CDH1 could explain the risk for cancer in HPC families with an excess of gastric and breast cancer. In total, 17 members from 13 HPC families and 3 members from 3 families with hereditary gastric cancer (HGC) were screened for germline CDH1 sequence alterations using PCR/Denaturing HPLC for initial screening of nucleotide variants followed by confirmatory direct sequencing analysis. The frequency of identified novel germline mutations were tested for in 136 cases with hereditary prostate cancer and 215 cases of sporadic prostate cancer with 422 age matched controls in an allelic discrimination assay. In total, 8 sequence variants were detected in 20 samples tested. In the HPC families, we found 2 missense mutations, A592T in exon 12 and a novel D777N in exon 15 and a mutation in intron 5, 687+92T>A. A previously known polymorphism in exon 13 and 3 sequence variations in introns and untranslated regions were also found, of which the significance is unknown. In HGC-023 with early onset diffuse gastric cancer a truncating mutation, R335X, was identified in exon 7. None of the missense mutations or 687+92T>A were found in the extended HPC material or in the sporadic prostate cancer cases with age-matched controls in the allelic discrimination assay. We found several germline mutations of unknown clinical significance in the CDH1 gene that probably do not explain the association of prostate, gastric and/or breast cancers in the HPC-families. Two missense mutations and a mutation in intron 5 were identified that do not influence the risk of hereditary or sporadic prostate cancer in general and are considered to be pedigree specific. In a family with hereditary gastric cancer of the diffuse type, we identified the first truncating germline mutation in a Scandinavian family.

OBJECTIVE

Germline mutations in the E-cadherin (CDH1) gene have been found in families with hereditary diffuse gastric cancer (HDGC). These families are characterized by a highly penetrant susceptibility to diffuse gastric cancer with an autosomal dominant pattern of inheritance. We describe the clinical presentation of three sibling cases with advanced gastric cancer, the way of confirming the suspicion of underlying HDGC and the clinical management of the other healthy family members.

METHODS

Screening for CDH1 germline mutation was carried out by denaturing high-performance liquid chromatography and automated DNA sequencing. The clinical suspicion of HDGC has been confirmed by identifying a frameshift mutation in exon 9 (1302_1303insA, 1306_1307delTT) of the E-cadherin gene.

RESULTS

Eight of nine tested family members were positive for the CDH1 germline mutation. Prophylactic laparoscopic gastrectomies were performed in five mutation carriers. After pathological examination, we could identify intramucosal malignant signet-ring cell carcinoma in all resected stomachs.

CONCLUSIONS

This report underlines that prophylactic gastrectomy remains the only option to eliminate the high risk for gastric cancer in CDH1 mutation carriers.

BACKGROUND

Germline mutation in the cell adhesion molecule E-cadherin is known to be associated with the development of undifferentiated or diffuse-type familial gastric cancers, but the prevalence of this contribution seems to be low in Japanese familial cases, so far.

METHODS

We screened all exons of the E-cadherin gene for mutations in 101 Japanese patients having an intense family history of gastric cancers.

RESULTS

An abnormal band pattern was found in exon 9 in three patients (Y6, B21, B37) from two families by PCR-SSCP. DNA sequencing analysis of these three patients revealed isoleucine-leucine substitution at codon 415 in exon 9. B21 and B37 are siblings and the other three brothers died of gastric cancer and another brother (B36) has not been affected by gastric cancer to date. This case (B36) did not have this alteration in the exon 9 of E-cadherin.

CONCLUSIONS

Although the mechanistic basis is not clear, our findings may provide a possibility that this additional missense mutation in germline E-cadherin gene may contribute to gastric cancer predisposition.

Erythropoietin (Epo) is the major regulator of differentiation, proliferation and survival of erythroid progenitors, but the Epo-induced changes in gene expression that lead to these effects are not fully understood. The aim of this study was to examine how Epo, via activation of phosphatidylinositol 3-kinase (PI3K)/Akt, exerts its role in the development of erythroid progenitors from CD34+ cells, and to identify early Epo target genes in human erythroid progenitors. In CD34+ progenitor cells, Epo alone was able to induce cell cycle progression as demonstrated by upregulation of cyclin D3, E and A leading to hyperphosphorylation of the retinoblastoma protein (RB). These effects were completely counteracted by the PI3K inhibitor LY294002. Furthermore, enforced expression of an activated form of Akt kinase highly augmented Epo-induced erythropoiesis. Fluorescent-activated cell sorting (FACS)-sorted CD34+CD71+CD45RA-GPA- erythroid progenitors stimulated with Epo in the presence or absence of LY294002 were subjected to gene expression profiling. Several novel target genes of Epo were identified, and the majority were regulated in a PI3K-dependent manner, including KIT (CD117) and CDH1 (E-cadherin). FACS analysis of Epo-stimulated erythroid progenitors showed that the increased mRNA expression of KIT and CDH1 was accompanied by an induction of the corresponding proteins CD117 and E-cadherin.

Cdh1, a coactivator of the anaphase-promoting complex (APC), is a potential tumor suppressor. Cdh1 ablation promotes precocious S-phase entry, but it was unclear how this affects DNA replication dynamics while contributing to genomic instability and tumorigenesis. We find that Cdh1 depletion causes early S-phase onset in conjunction with increase in Rb/E2F1-mediated cyclin E1 expression, but reduced levels of cyclin E1 protein promote this transition. We hypothesize that this is due to a weakened cyclin-dependent kinase inhibitor (CKI)-cyclin-dependent kinase 2 positive-feedback loop, normally generated by APC-Cdh1-mediated proteolysis of Skp2. Indeed, Cdh1 depletion increases Skp2 abundance while diminishing levels of the CKI p27. This lowers the level of cyclin E1 needed for S-phase entry and delays cyclin E1 proteolysis during S-phase progression while corresponding to slowed replication fork movement and reduced frequency of termination events. In summary, using both experimental and computational approaches, we show that APC-Cdh1 establishes a stimulus-response relationship that promotes S phase by ensuring that proper levels of p27 accumulate during G1 phase, and defects in its activation accelerate the timing of S-phase onset while prolonging its progression.

The simian polyoma virus SV40 has been detected in specific human tumors including non-Hodgkin's lymphomas, although a causative role for the virus has not been convincingly demonstrated. Aberrant methylation of CpG islands in promoter regions is a frequent method of silencing tumor suppressor genes (TSGs) in cancers and may be induced by oncogenic viruses. We investigated the relationship between the presence of SV40 or EBV DNA sequences and the methylation profiles for 10 TSGs in 90 cases of non-Hodgkin's lymphomas/leukemias and 56 control tissues. SV40 sequences were present in 33/90 (37%) non-Hodgkin's lymphomas/leukemias, and EBV was present in 11/42 (26%) of non-Hodgkin's lymphomas. We found a highly significant correlation between the presence of SV40 and methylation of seven genes (P values, 0.006 to <0.0001). In lymphomas, there was no relationship between EBV and methylation. Oncogenic viruses and methylation were rarely present in control tissues. We investigated methylation of the same 10 TSGs in peripheral blood mononuclear cells (PBMC) from a healthy volunteer infected with EBV or EBV and SV40. Promoter methylation of <em>CDH1</em> and <em>CDH1</em>3 were noted in dual SV40- and EBV-infected PBMC, and these two genes were also highly significantly correlated to the presence of SV40 sequences in tumors. SV40 infection also resulted in appearance of the lymphoma/leukemia-specific marker, methylated SHP1. Methylation was completely absent in uninfected and EBV-infected PBMC. Our results demonstrate that the presence of SV40 in hematological malignancies is associated with promoter methylation of TSGs and that in all probability, the virus plays a role in tumor pathogenesis.

Identifying molecular factors of sensitivity and resistance of cancer cells to enzastaurin, a drug inhibiting protein kinase C (PKC) beta, remains a major challenge to improve its clinical development. Investigating the cellular effects of enzastaurin in a panel of 20 human cancer cell lines, we found that most cells displaying oncogenic K-Ras mutations also display resistance to enzastaurin. Wild-type (WT) K-Ras cancer cells displaying high sensitivity to enzastaurin also expressed high mRNA levels of epithelial markers, such as E-cadherin (CDH1), and low mRNA expressions of mesenchymal markers, such as vimentin, N-cadherin (CDH2), and other genes frequently expressed in mesenchymal transition such as ZEB1, TWIST, SLUG, SNAIL, and TGFbeta. WT K-Ras enzastaurin-resistant cells also expressed high levels of mesenchymal markers. Based on this observation, the effects of enzastaurin were investigated in epithelial colon COLO205-S cells that expressed WT Ras/Raf and its derived COLO205-R mesenchymal counterpart selected for resistance to most PKC modulators and displaying oncogenic K-Ras (G13D/exon 2). In COLO205-S cells, inhibition of phosphorylated PKCbeta led to the inactivation of AKT and glycogen synthase kinase 3beta and was associated with apoptosis without significant effect on cell cycle progression. In COLO205-R cells, enzastaurin induced mainly necrosis at high concentrations. In COLO205-R cells, a strong activation of extracellular signal-regulated kinase 1/2 possibly due to oncogenic K-Ras was predominantly associated with transcription of potent antiapoptotic genes, such as BCL2, GADD45B, and CDKN1A, as well as the multidrug resistance gene ABCB1. From this study, colon cancer cells undergoing apoptosis under enzastaurin exposure seem to frequently express a WT Ras and an epithelial phenotype.

While studying on epigenetic regulatory mechanisms (DNA methylation at C-5 of -CpG- cytosine and demethylation of methylated DNA) of certain genes (FAS, CLU, E-cadh, CD44, and Cav-1) associated with prostate cancer development and its better management, we noticed that the used in vivo dose of 5-aza-2'-deoxycytidine (5.0 to 10.0 nM, sufficient to inhibit DNA methyltransferase activity in vitro) helped in the transcription of various genes with known (steroid receptors, AR and ER; ER variants, CD44, CDH1, BRCA1, TGFβR1, MMP3, MMP9, and UPA) and unknown (DAZ and Y-chromosome specific) proteins and the respective cells remained healthy in culture. At a moderate dose (20 to 200 nM) of the inhibitor, cells remain growth arrested. Upon subsequent challenge with increased dose (0.5 to 5.0 μM) of the inhibitor, we observed that the cellular morphology was changing and led to death of the cells with progress of time. Analyses of DNA and anti-, pro-, and apoptotic factors of the affected cells revealed that the molecular events that went on are characteristics of programmed cell death (apoptosis).

Loss of heterozygosity (LOH) in 16q appears in ~20-30% cases of Wilms' tumor. Within this region, known as common fragile site FRA16D, the WWOX tumor suppressor gene is located. Abnormalities of WWOX gene expression levels were observed in many tumor types and were associated with worse prognosis. The purpose of this study was to investigate the role of the WWOX tumor suppressor gene in Wilms' tumor samples. We evaluated the correlation between expression of WWOX and genes involved in proliferation (Ki67), apoptosis (BCL2, BAX), signal transduction (ERBB4, ERBB2, EGFR), cell cycle (CCNE1, CCND1), cell adhesion (CDH1) and transcription (TP73) using real-time RT-PCR in 23 tumor samples. We also analyzed the potential causes of WWOX gene expression reduction i.e., promoter methylation status (MethylScreen method) and loss of heterozygosity (LOH) status. We revealed a positive correlation between WWOX expression and BCL2, BCL2/BAX ratio, EGFR, ERBB4 isoform JM-a, TP73 and negative correlation with both cyclins. Loss of heterozygosity of the WWOX gene was observed only at intron 8, however, it had no influence on the reduction of its expression levels. Contrary to LOH, methylation of the region covering the 3' end of the promoter and part of exon 1 was associated with statistically significant reduction of WWOX gene expression levels. In the present study we reveal that in Wilms' tumors the WWOX expression levels are positively associated with the process of apoptosis, signal transduction through the ErbB4 pathway and EGFR and negatively with the regulation of the cell cycle (by cyclin E1 and D1). Moreover, our analysis indicates that in this type of tumor the expression of the WWOX gene can be regulated by an epigenetic mechanism--its promoter methylation.

BACKGROUND

Gene panel testing for breast cancer susceptibility has become relatively cheap and accessible. However, the breast cancer risks associated with mutations in many genes included in these panels are unknown.

METHODS

We performed custom-designed targeted sequencing covering the coding exons of 17 known and putative breast cancer susceptibility genes in 660 non-BRCA1/2 women with familial breast cancer. Putative deleterious mutations were genotyped in relevant family members to assess co-segregation of each variant with disease. We used maximum likelihood models to estimate the breast cancer risks associated with mutations in each of the genes.

RESULTS

We found 31 putative deleterious mutations in 7 known breast cancer susceptibility genes (TP53, PALB2, ATM, CHEK2, CDH1, PTEN and STK11) in 45 cases, and 22 potential deleterious mutations in 31 cases in 8 other genes (BARD1, BRIP1, MRE11, NBN, RAD50, RAD51C, RAD51D and CDK4). The relevant variants were then genotyped in 558 family members. Assuming a constant relative risk of breast cancer across age groups, only variants in CDH1, CHEK2, PALB2 and TP53 showed evidence of a significantly increased risk of breast cancer, with some supportive evidence that mutations in ATM confer moderate risk.

CONCLUSIONS

Panel testing for these breast cancer families provided additional relevant clinical information for <2% of families. We demonstrated that segregation analysis has some potential to help estimate the breast cancer risks associated with mutations in breast cancer susceptibility genes, but very large case-control sequencing studies and/or larger family-based studies will be needed to define the risks more accurately.

Aberrant DNA methylation has been observed in cervical cancer; however, most studies have used non-quantitative approaches to measure DNA methylation. The objective of this study was to quantify methylation within a select panel of genes previously identified as targets for epigenetic silencing in cervical cancer and to identify genes with elevated methylation that can distinguish cancer from normal cervical tissues. We identified 49 women with invasive squamous cell cancer of the cervix and 22 women with normal cytology specimens. Bisulfite-modified genomic DNA was amplified and quantitative pyrosequencing completed for 10 genes (APC, CCNA, <em>CDH1</em>, <em>CDH1</em>3, WIF1, TIMP3, DAPK1, RARB, FHIT, and SLIT2). A Methylation Index was calculated as the mean percent methylation across all CpG sites analyzed per gene (~4-9 CpG site) per sequence. A binary cut-point was defined at >15% methylation. Sensitivity, specificity and area under ROC curve (AUC) of methylation in individual genes or a panel was examined. The median methylation index was significantly higher in cases compared to controls in 8 genes, whereas there was no difference in median methylation for 2 genes. Compared to HPV and age, the combination of DNA methylation level of DAPK1, SLIT2, WIF1 and RARB with HPV and age significantly improved the AUC from 0.79 to 0.99 (95% CI: 0.97-1.00, p-value = 0.003). Pyrosequencing analysis confirmed that several genes are common targets for aberrant methylation in cervical cancer and DNA methylation level of four genes appears to increase specificity to identify cancer compared to HPV detection alone. Alterations in DNA methylation of specific genes in cervical cancers, such as DAPK1, RARB, WIF1, and SLIT2, may also occur early in cervical carcinogenesis and should be evaluated.

Multi-gene panels are used to identify genetic causes of hereditary breast and ovarian cancer (HBOC) in large patient cohorts. This study compares the diagnostic workflow in two centers and gives valuable insights into different next-generation sequencing (NGS) strategies. Moreover, we present data from 620 patients sequenced at both centers. Both sequencing centers are part of the German consortium for hereditary breast and ovarian cancer (GC-HBOC). All 620 patients included in this study were selected following standard BRCA1/2 testing guidelines. A set of 10 sequenced genes was analyzed per patient. Twelve samples were exchanged and sequenced at both centers. NGS results were highly concordant in 12 exchanged samples (205/206 variants = 99.51 %). One non-pathogenic variant was missed at center B due to a sequencing gap (no technical coverage). The custom enrichment at center B was optimized during this study; for example, the average number of missing bases was reduced by a factor of four (vers. 1: 1939.41, vers. 4: 506.01 bp). There were no sequencing gaps at center A, but four CCDS exons were not included in the enrichment. Pathogenic mutations were found in 12.10 % (75/620) of all patients: 4.84 % (30/620) in BRCA1, 4.35 % in BRCA2 (27/620), 0.97 % in CHEK2 (6/620), 0.65 % in ATM (4/620), 0.48 % in CDH1 (3/620), 0.32 % in PALB2 (2/620), 0.32 % in NBN (2/620), and 0.16 % in TP53 (1/620). NGS diagnostics for HBOC-related genes is robust, cost effective, and the method of choice for genetic testing in large cohorts. Adding 8 genes to standard BRCA1- and BRCA2-testing increased the mutation detection rate by one-third.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive and lethal malignancies. Given that macroautophagy/autophagy activation is prevalent in PDAC, the dual roles of autophagy could be involved in PDAC heterogeneity. In this work, we demonstrated that TGFB1 induced autophagic flux through SMAD4-dependent or SMAD4-independent pathways based on a distinct genetic context. In SMAD4-positive PDAC cells, TGFB1-induced autophagy promoted proliferation and inhibited migration by decreasing the nuclear translocation of SMAD4. Conversely, TGFB1-induced autophagy inhibited proliferation and promoted migration in SMAD4-negative cells through the regulation of MAPK/ERK activation. TGFB1 expression also positively correlated with LC3B expression in PDAC specimens. A high level of LC3B was associated with unfavorable overall survival (OS) and disease-free survival (DFS) in SMAD4-negative PDAC patients, although LC3B could not predict OS and DFS for the 110 PDAC patients. Thus, TGFB1-induced autophagy contributed to the different patterns of PDAC progression. This knowledge can aid in improving our understanding of the molecular classification of PDAC and might guide the development of therapeutic strategies for PDAC, especially for SMAD4-negative PDAC. Abbreviations: CDH1: cadherin 1; CDH2: cadherin 2; CI: combination index; CQ: chloroquine; DFS: disease-free survival; EMT: epithelial-to-mesenchymal transition; ERK: extracellular signal-regulated protein kinase; GFP: green fluorescent protein; IHC: immunohistochemistry; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; MAPK: mitogen-activated protein kinase; OS: overall survival; PBS: phosphate-buffered saline; PDAC: pancreatic ductal adenocarcinoma; RAP: rapamycin; RFP: red fluorescent protein; RT: room temperature; shRNA: short-hairpin RNA; SQSTM1: sequestosome 1; TCGA: The Cancer Genome Atlas; TEM: transmission electron microscopy; TGFB1: transforming growth factor beta 1; TMA: tissue microarray.

SNAI1, SNAI2, and SNAI3 genes, encoding transcriptional repressors implicated in epithelial mesenchymal transition (EMT), are human homologs of Drosophila snail (sna) and slug genes. SNAI1 represses transcription of CDH1 (E-cadherin) gene. SNAI2 induces the first phase of EMT, including desmosome dissociation, cell spreading, and initiation of cell separation. Because SNAI family proteins are implicated in EMT during embryogenesis and carcinogenesis, SNAI family genes are potent targets of pharmacogenomics. Here, comparative genomics analyses and comparative proteomics analyses on SNAI family orthologs were performed. Rat Snai3 gene, consisting of three exons, was identified within rat genome sequence AC111791.4. Zebrafish snai1a (NM_131066.1) was identified as SNAI1 ortholog. Chicken ChEST362l17 (CR407272.1), Xenopus slug (AF368041.1), and zebrafish zgc92564 (NM_001008581.1) were identified as SNAI2 orthologs. Chicken snail (NM_ 205142.1), Xenopus snail (BC056857.1), and zebrafish snai1b (NM_130989.1) were identified as SNAI3 orthologs. SNAI1 orthologs consisted of SNAG domain and four zinc finger (ZNF) domains, while SNAI2 and SNAI3 orthologs consisted of SNAG domain and five ZNF domains. Based on the integromics analyses, SNAI2 orthologs were found to be more conserved than SNAI1 and SNAI3 orthologs. SNAI1 mRNA was expressed in placenta, neuroblastoma, and diffuse type gastric cancer. SNAI2 mRNA was expressed in placenta, melanocyte, embryonic stem (ES) cells, leiomyosarcoma, neuroblastoma, and glioblastoma. SNAI3 mRNA was expressed in B cells. Expression of SNAI3 mRNA was repressed due to the existence of anti-sense single-exon transcript. SNAI1, functioning as E-cadherin repressor, is implicated in the malignant infiltrating phenotype of diffuse type gastric cancer through the induction of EMT or fibroblastoid transformation.

BACKGROUND

Promoter hypermethylation of tumor suppressor genes is one of the major events in gastric carcinogenesis. Promoter hypermethylation is also present in non-neoplastic gastric epithelium as age-related phenomenon and some reports suggest the potential association between promoter hypermethylation and Helicobacter pylori infection. Here, we examined whether methylation of multiple promoter CpG islands would occur by H. pylori infection and correlate with histological or serological severity of chronic gastritis.

METHODS

One hundred and ninety-one gastric mucosa samples were obtained by endoscopy. The promoter methylation status of the p14, p16, DAP-kinase and CDH1 genes were determined by methylation-specific-polymerase chain reaction. The degree of gastritis in the antrum was assessed according to the updated Sydney system in 150 participants. The pepsinogen (PG) I/II ratio was calculated based on the data of serum PG I and PG II levels measured by radioimmunoassay in 54 selected cases.

RESULTS

CpG island methylation was found in 32.5% for p14, 35.1% for p16, 43.5% for DAP-kinase and 36.1% for CDH1, whereas non, 1, 2, 3, and all methylation of four promoter CpG sites were present in 46 (24.1%), 59 (30.9%), 46 (24.1%), 30 (15.7%), and 10 (5.2%) participants, respectively. A strong association between the increased number of methylated CpG islands and H. pylori infection was observed (P<0.0001). An increased number of methylated CpG islands was also associated with severity of neutrophil infiltration (P<0.0001), mononuclear cell infiltration (P<0.0001) and atrophy (P=0.0021) in all, and severity of neutrophil infiltration (P=0.0177) and mononuclear cell infiltration (P=0.0004) in H. pylori-positive participants. An increased number of methylated CpG islands correlated with lower PG I/II ratio in all (P=0.0105) and H. pylori-infected participants (P=0.074).

CONCLUSIONS

Multiple promoter CpG islands would be methylated by H. pylori infection, and an increased number of methylated CpG sites correlate with histological and serological severity of chronic gastritis.