Alterations of Fas (Apo-1/CD95) gene in non-small cell lung cancer

Therapeutic approaches targeting CD95L/CD95 signaling in cancer and autoimmune diseases

Cell death plays a pivotal role in the maintenance of tissue homeostasis. Key players in the controlled induction of cell death are the Death Receptors (DR). CD95 is a prototypic DR activated by its cognate ligand CD95L triggering programmed cell death. As a consequence, alterations in the CD95/CD95L pathway have been involved in several disease conditions ranging from autoimmune diseases to inflammation and cancer. CD95L-induced cell death has multiple roles in the immune response since it constitutes one of the mechanisms by which cytotoxic lymphocytes kill their targets, but it is also involved in the process of turning off the immune response. Furthermore, beyond the canonical pro-death signals, CD95L, which can be membrane-bound or soluble, also induces non-apoptotic signaling that contributes to its tumor-promoting and pro-inflammatory roles. The intent of this review is to describe the role of CD95/CD95L in the pathophysiology of cancers, autoimmune diseases and chronic inflammation and to discuss recently patented and emerging therapeutic strategies that exploit/block the CD95/CD95L system in these diseases.

Clonal Structures of Regionally Synchronous Gastric Adenomas and Carcinomas

Purpose: Gastric adenoma (GA) is a premalignant lesion that precedes intestinal-type gastric carcinoma (GC). However, genetic progression mechanisms from GA to GC have not been clarified.Experimental Design: We performed whole-exome sequencing-based mutational analyses for 15 synchronous pairs of attached GAs and GCs.Results: There was no significant difference in the number of driver mutations or copy-number alterations between GAs and GCs. Well-known mutations of TP53, APC, RNF43, and RPL22 were recurrently detected in synchronous GA/GC pairs. In addition, we discovered novel KDM6A, PREX2, FAT1, KMT2C, GLI3, and RPL22 mutations and hypermutation in GAs, but did not identify recurrent drivers for GA-to-GC progression. Clonal structure analyses revealed that most GA/GC pairs exhibit parallel evolution with early divergence rather than stepwise evolution during GA-to-GC progression. Of note, three cases were identified as clonally nonrelated GA/GC pairs despite the lack of histologic differences. We found differences in dominant mutational signatures 1, 6, 15, and 17 in GA/GC trunks, GA branches, and GC branches. Compared with our previous work on synchronous colon adenoma/carcinoma genome structures, where most drivers were in the trunk with parallel evolution, synchronous GA/GC genomes showed a different model of parallel evolution, with many drivers in the branches.Conclusions: The preferred sequence of mutational events during GA-to-GC progression might be more context-dependent than colon adenoma progression. Our results show that nonclonal synchronous GA/GC is common and that GA genomes have already acquired distinct genomic alterations, suggesting caution in the diagnosis of synchronous GA and GC, especially in residual or recurrent cases. Clin Cancer Res; 24(19); 4715-25. ©2018 AACR.

Mutational and Expressional Analyses of MYD88 Gene in Common Solid Cancers

Aims and background

Myeloid differentiation primary response gene 88 (MYD88) is a protein involved in hematopoietic differentiation and innate immunity. Recent studies revealed MYD88 mutation in hematological malignancies and MYD88 overexpression in some solid cancers. The aim of this study was to see whether alterations of MYD88 protein expression and somatic mutation of MYD88 gene are features of common solid cancers.

Methods

We analyzed MYD88 mutation in 45 gastric, 45 colorectal, 45 breast, 45 hepatocellular, 45 prostate and 45 lung carcinomas by single-strand conformation polymorphism (SSCP). We also analyzed MYD88 protein expression in 60 gastric, 60 coloretal and 107 prostate carcinomas by immunohistochemistry.

Results

In the immunohistochemistry results, MYD88 protein was highly expressed in gastric (75%), colorectal (80%) and prostate (83%) cancers. However, MYD88 expression was significantly different among normal tissues (gastric: 58%, colon: 100%, prostate: 86%). MYD88 expression was significantly increased in gastric cancer cells compared with normal cells, whereas it was decreased in colorectal cancer cells compared with normal cells. There were no somatic mutations of the MYD88 gene in gastric, colorectal, breast, hepatocellular, prostate and lung carcinomas.

Conclusions

Our data indicate that MYD88 overexpression might be a feature of many solid cancers, but MYD88 expression in normal cells differs depending on the organs. The data suggest that a gain of MYD88 expression in gastric cancers might play a role in cancer pathogenesis by activating oncogenic functions of MYD88.

Rare somatic mutation of pro-apoptotic BAX and BAK genes in common human cancers

Aims and background

BAX and BAK are both pro-apoptotic Bcl-2 proteins and are essential for the pathway of intrinsic apoptosis. Apoptosis in cancer cells is frequently inactivated by somatic mutations. The aim of the study was to see whether somatic mutations of BAX and BAK genes are characteristics of common human cancers.

Methods

We analyzed somatic mutation of BAX and BAK genes in 47 gastric, 47 colorectal, 47 breast, 47 lung and 47 prostate carcinomas, and 47 acute leukemias by a polymerase chain reaction and single-strand conformation polymorphism assay.

Results

We identified BAX gene mutations in one colon (2.1%) and three gastric (6.4%) cancers. All of the mutations were frameshift mutations in the G8 repeat sequences and were detected in cancers with high microsatellite instability (36.4%). There was no evidence of BAX mutation in the other cancers, nor was somatic mutation of the BAK gene detected in the cancers.

Conclusions

Our data indicate that somatic mutation of BAX and BAK genes are rare in the common cancers (besides the cancers with high microsatellite instability) and suggest that neither BAX nor BAK mutation may causally be implicated in their tumorigenesis.

Absence of Paxillin Gene Mutation in Lung Cancer and other Common Solid Cancers

Aims and background

Mounting evidence indicates that deregulated cell adhesion is involved in the mechanisms of cancer pathogenesis. A recent study showed that the paxillin gene (PXN) encoding a focal adhesion protein was somatically mutated in lung cancers. The aim of this study was to confirm the presence of PXN mutations in lung cancers as well as in other common solid cancers.

Methods

We analyzed somatic PXN mutations in 45 lung, 45 gastric, 45 colorectal, 45 breast, 45 liver and 45 prostate cancers by polymerase chain reaction and single-strand conformation polymorphism assay.

Results

Neither lung nor other cancers were found to be associated with somatic mutations of PXN.

Conclusions

In contrast to the previous report, our study revealed that PXN mutation was absent in lung cancers and other common solid cancers, suggesting that PXN mutation may not play a principal role in solid cancer development.

Expression and Mutation Analyses of Fas, FLIP and Bcl-2 in Granulosa Cell Tumor of Ovary

Aims and background

Mounting evidence indicates that evasion of apoptosis contributes to tumor pathogenesis. Although both Fas and Bcl-2 are crucial in apoptosis of normal ovarian cells, their roles in ovarian tumors, especially stromal tumors, are largely unknown. The aim of this study was to explore mutation of the Fas gene and expression of the apoptosis-related proteins Fas, FLICE-like inhibitory protein (FLIP) and Bcl-2 in granulosa cell tumor (GCT) of the ovary.

Methods

We analyzed the expression of Fas, FLIP and Bcl-2 in 20 GCT tissues by immunohistochemistry. We also analyzed somatic mutations of the Fas gene in the same GCT tissues by polymerase chain reaction and single-strand conformation polymorphism assay.

Results

Expression of Fas was evident in 12 GCTs (60%), but the remaining 8 GCTs showed no or markedly decreased Fas immunostaining. Expression of FLIP was identified in 30% of the GCT samples and expression of Bcl-2 in 75%. All GCTs with positive Fas expression (n = 12) showed either FLIP or Bcl-2 expression. The GCTs were found to carry no somatic Fas mutations.

Conclusions

Our data show that alterations of the apoptosis-related proteins Fas, FLIP and Bcl-2 are common in GCT, and suggest that expression of FLIP and Bcl-2 and loss of Fas expression might play role in the pathogenesis of GCT, possibly by inhibiting apoptosis.

Mutational Analysis of the BH3 Domains of Proapoptotic Bcl-2 Family Genes Bad, Bmf and Bcl-G in Laryngeal Squamous Cell Carcinomas

Aims

There is mounting evidence that deregulation of apoptosis is involved in the mechanisms of cancer development. Somatic mutations of apoptosis-related genes have been reported in many human cancers. The aim of this study was to explore the possibility that mutation of the BH3 domains of the proapoptotic Bcl-2 genes Bad, Bmf and Bcl-G might be involved in the development of laryngeal cancer.

Methods

We analyzed the BH3 domains of Bad, Bmf and Bcl-G for the detection of somatic mutations in 33 squamous cell carcinomas of the larynx by a polymerase chain reaction-based single-strand conformation polymorphism assay.

Results

There were no somatic mutations of the BH3 domains of Bad, Bmf and Bcl-G in the laryngeal squamous cell carcinoma samples.

Conclusions

The data presented here indicate that BH3 domain mutation of the proapoptotic genes Bad, Bmf and Bcl-G is rare in laryngeal squamous cell carcinoma and may not contribute to the apoptosis-resistance mechanisms of laryngeal squamous cell carcinoma.

Mutational Analysis of Proapoptotic Integrin Beta 3 Cytoplasmic Domain in Common Human Cancers

Aims

Mounting evidence indicates that deregulation of apoptosis is involved in the mechanisms of cancer development. Integrins are cell adhesion receptors that mediate cell survival and migration. A recent study showed that unligated integrin beta 3 (ITGB3) induced apoptosis by recruitment of caspase-8. The aim of the present study was to explore the possibility that genetic alteration of the ITGB3 gene is involved in the development of human cancers possibly by inactivating the apoptosis function of ITGB3.

Methods

We analyzed the coding region of the cytoplasmic domain of the human ITGB3 gene for the detection of somatic mutations in 100 gastric, 90 colorectal, 100 non-small cell lung, 43 urinary bladder and 50 head-neck cancers by a polymerase chain reaction-based, single-strand conformation polymorphism.

Results

We found an identical ITGB3 mutation in two unrelated patient samples (one in colorectal and the other in bladder cancer). The ITGB3 mutation was a missense mutation which would substitute an amino acid (E757K).

Conclusions

The data suggested that the proapoptotic ITGB3 cytoplasmic domain is rarely mutated in common human cancers and may not play an important role in the development of the cancers.

Expression Analysis of caspase-6, caspase-9 and BNIP3 in Prostate Cancer

Aims

Altered regulation of cell death is a feature of human cancer. The aim of this study was to explore whether the expression of the proapoptotic proteins caspase-6, caspase-9, and Bcl-2/adenovirus E1B-19kDa-interacting protein3 (BNIP3) is altered in prostate cancers.

Methods

We analyzed the expression of caspase-6, caspase-9, and BNIP3 in 107 prostate adenocarcinoma tissues by immunohistochemistry using a tissue microar-ray (TMA) method.

Results

Normal glandular cells expressed caspase-6 and BNIP3 proteins in 10 (9.3%) and 9 (8.4%) prostate tissues, respectively. By contrast, the prostate cancers expressed caspase-6 and BNIP3 in 65 (60.7%) and 69 (64.5%) cases, respectively. Prostate intraepithelial neoplasia (PIN) showed caspase-6 and BNIP3 expression in 65% and 65% of cases, respectively. We observed caspase-9 expression in 40 (37.4%) normal, 8 (40%) PIN, and 45 (42.1%) cancer tissues. None of the expression of caspase-6, caspase-9 or BNIP3 was associated with pathological characteristics such as tumor size, patient age, Gleason score, or tumor stage.

Conclusion

Our data showed that prostate cancer and PIN cells display higher expression of the proapoptotic proteins caspase-6 and BNIP3 than normal cells. Neoexpression of these proteins from the PIN stage suggests that apoptosis deregulation might occur in the early stage of prostate carcinogenesis, and that altered expression of proapoptotic proteins may be a feature of prostate cancer.

Increased Expression of Endonuclease G in Gastric and Colorectal Carcinomas

Aims

Endonuclease G (EndoG) is a mitochondrial protein that plays a role in DNA fragmentation during apoptosis. In addition, EndoG plays a role in cell proliferation and survival. It may be important to identify EndoG protein expression to predict its function in human cancers. The aim of this study was to explore whether alteration of EndoG expression might be a characteristic of colorectal or gastric carcinoma.

Methods

We investigated EndoG protein expression in 103 colorectal and 60 gastric carcinoma tissues by immunohistochemistry using a tissue microarray approach.

Results

Expression of EndoG was detected in 72 (70%) of the colorectal carcinomas and 41 (68%) of the gastric carcinomas in cytoplasm. By contrast, normal mucosal cells of both stomach and colon tissues showed no or very weak expression of EndoG. There was no significant association of EndoG expression with clinocopathological characteristics, including invasion, metastasis and stage.

Conclusion

Our data indicate that EndoG inactivation by loss of expression may not occur in colorectal and gastric cancers. Rather, increased expression of EndoG in colorectal and gastric cancer cells compared to their normal mucosal epithelial counterparts suggests that neo-expression of EndoG may play a role in both colorectal and gastric tumorigenesis.

Prognostic Investigations of Expression Level of Two Genes FasL and Ki-67 as Independent Prognostic Markers of Human Retinoblastoma

In this study, expression of FasL and Ki-67 messenger RNA (FasL and Ki-67 mRNA) in human retinoblastoma (HRB) was examined by the immunohistochemistry method and quantitative real-time PCR. Positive expression of Ki-67 in tumor cells was detected in 16 of 30 patients (53.33%), and only 9 (30%) of the tissues from patients with retinoblastoma showed positive staining for FasL. Our results revealed that FasL expression was significantly higher in tumor tissue with invasion compared with the noninvasion form (p = 0.033). Ki-67 expression was markedly increased in tumor tissues with invasion compared with the noninvasion group (p = 0.04), but no significant correlation was found between FasL expression and differentiation (p > 0.05). In addition, Ki-67 expression was strongly linked to differentiation (p < 0.002). Expression of these FasL was correlated with shorter overall survival of patients, but its expression was not significantly associated with overall survival (p = 0.15). The impact of Ki-67 expression on survival in patients was also evaluated. Ki-67 expression level was not found to be significantly associated with shorter survival (Kaplan–Meier; p = 0.09). Univariate analysis revealed that massive choroidal invasion was correlated with poor prognosis. Taken together, the data suggest that massive choroidal invasion is also an important indicator of poor prognosis for HRB.

Mutations of Fas (APO-1/CD95) and p53 Genes in Nonmelanoma Skin Cancer

Background:

There is considerable evidence that apoptosis plays an important role in the pathogenesis of a wide variety of skin diseases. Apoptosis failure may ensure the survival of transformed cells prone to sustain further genetic damage and it plays an important part in the development of tumors. Genetic alterations of Fas and p53, with consequent inactivation of gene protein products, may be involved in transcriptional downregulation of Fas.

Objective:

We investigated Fas and its ligand expression in 30 cases of nonmelanoma skin cancer, 19 basal cell and 11 squamous cell carcinomas, and we also analyzed Fas and p53 status, in an attempt to detect putative alterations.

Method:

Fas and its ligand expression were evaluated by RT-PCR; the promoter and the entire coding region of Fas, and the coding exons 4–9 of p53 were investigated by polymerase chain reaction, single strand conformation polymorphism, and DNA sequencing.

Results:

Fas alterations were found in 3/19 (15.8%) basal cell and in 4/11 (36.4%) squamous cell carcinomas. Five out of 25 cases (3/19 basal cell and 2/11 squamous cell carcinomas) were p53-mutated, and in the majority of these cases there were concomitant mutations of the Fas gene (χ2 test; p = 0.035).

Conclusion:

Taken together, our findings highlight an involvement of the Fas/Fas-ligand system in the development of skin cancer, suggesting that the loss of its apoptotic function, in some cases linked to p53 alterations, may contribute to the self-maintenance of cancer cells.

Clonal origins and parallel evolution of regionally synchronous colorectal adenoma and carcinoma

Although the colorectal adenoma-to-carcinoma sequence represents a classical cancer progression model, the evolution of the mutational landscape underlying this model is not fully understood. In this study, we analyzed eight synchronous pairs of colorectal high-grade adenomas and carcinomas, four microsatellite-unstable (MSU) and four -stable (MSS) pairs, using whole-exome sequencing. In the MSU adenoma-carcinoma pairs, we observed no subclonal mutations in adenomas that became fixed in paired carcinomas, suggesting a ‘parallel’ evolution of synchronous adenoma-to-carcinoma, rather than a ‘stepwise’ evolution. The abundance of indel (in MSU and MSS pairs) and microsatellite instability (in MSU pairs) was noted in the later adenoma- or carcinoma-specific mutations, indicating that the mutational processes and functional constraints operative in early and late colorectal carcinogenesis are different. All MSU cases exhibited clonal, truncating mutations in ACVR2A, TGFBR2, and DNA mismatch repair genes, but none were present in APC or KRAS. In three MSS pairs, both APC and KRAS mutations were identified as both early and clonal events, often accompanying clonal copy number changes. An MSS case uniquely exhibited clonal ERBB2 amplification, followed by APC and TP53 mutations as carcinoma-specific events. Along with the previously unrecognized clonal origins of synchronous colorectal adenoma-carcinoma pairs, our study revealed that the preferred sequence of mutational events during colorectal carcinogenesis can be context-dependent.

Distinct role of the Fas rs1800682 and FasL rs763110 polymorphisms in determining the risk of breast cancer among Han Chinese females

Background

In recent years, studies have demonstrated that polymorphisms in the promoters of Fas and FasL are significantly associated with breast cancer risk. However, the results of these studies were inconsistent. This case–control study was performed to explore the associations between Fas rs1800682 and FasL rs763110 polymorphisms and breast cancer.

Materials and methods

A hospital-based case–control study of 560 Han Chinese females with breast cancer (583 controls) was conducted. The MassARRAY system was used to search for a possible association between the disease risk and the two single nucleotide polymorphisms, Fas rs1800682 and FasL rs763110. Statistical analyses were performed using SNPStats software to conduct Pearson’s chi-square tests in five different genetic models. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated after adjustment to age and body mass index. PHASE v2.1 software was used to reconstruct all common haplotypes.

Results

A statistically significant association was found between Fas rs1800682 and increased breast cancer risk (AG vs AA: OR =1.37, 95% CI =1.06–1.78; AA+AG vs GG: OR =1.32, 95% CI =1.04–1.66), and also it was found that the FasL rs763110 polymorphism may decrease the risk. Stratified analyses demonstrated that the rs763110 polymorphism was associated with lower breast cancer risk among postmenopausal females (heterozygote model: OR =0.69, 95% CI =0.49–0.97; dominant model: OR =0.70, 95% CI =0.51–0.96). The T allele of rs763110 was also associated with a decreased risk of lymph node metastasis (allele model: OR =0.75, 95% CI =0.57–0.97) and an increased risk of the breast cancer being human epidermal growth factor receptor 2 positive (allele model: OR =1.37, 95% CI =1.03–1.18). Moreover, haplotype analysis showed that A_rs1800682T_rs763110 was associated to a statistically significant degree with lower risk of breast cancer (OR =0.70, 95% CI =0.53–0.91).

Conclusion

These data suggest that the presence of Fas rs1800683 is an important risk factor for breast cancer, whereas FasL rs763110 may exert a protective effect against the onset of breast cancer.

Quantitative assessment of the association between Fas/FasL gene polymorphism and susceptibility to esophageal carcinoma in a north Chinese population

The case–control study aims to investigate the association of Fas and FasL genetic polymorphisms (Fas‐670A/G (rs1800682), Fas‐1377G/A (rs2234767) and FasL‐844T/C (rs763110)) with esophageal carcinoma susceptibility in a north Chinese population. A total of 204 patients with esophageal carcinoma and 248 healthy controls were enrolled from Henan, China and genotyped by the polymerase chain reaction and restriction fragment length polymorphism method. There were no significant differences in distributions of their genotypes frequencies between patients and controls in Fas‐670A/G, Fas‐1377G/A and FasL‐844T/C polymorphisms (P > 0.05). Stratified analysis showed that no significant association was found between esophageal carcinoma and gene polymorphisms of Fas‐670 A/G, Fas‐1377G/A, and FasL‐844T/C (P > 0.05). Genetic polymorphisms in the death pathway genes Fas and FasL were not associated with risk of developing esophageal carcinoma in a north Chinese population.

The combined risks of reduced or increased function variants in cell death pathway genes differentially influence cervical cancer risk and herpes simplex virus type 2 infection among black Africans and the Mixed Ancestry population of South Africa

Background

Cervical cancer is one of the most important cancers worldwide with a high incident and mortality rate and is caused by the human papilloma virus (HPV). Among sexually active women who get infected with human papillomavirus (HPV), a small fraction progresses to cervical cancer disease pointing to possible roles of additional risk factors in development of the disease which include host genetic factors and other infections such as HSV-2. Since cellular apoptosis plays a role in controlling the spread of virus-infections in cells, gene variants altering the function of proteins involved in cell death pathways might be associated with the clearing of virus infections. Activity altering polymorphisms in FasR (−1377G > A and -670A > G), FasL (−844 T > C) and CASP8 (−652 6 N ins/del) genes have been shown to alter the mechanism of apoptosis by modifying the level of expression of their correspondent proteins.

In the present study, we set out to investigate the combined risks of CASP8, FasR, and FasL polymorphisms in cervical cancer, pre-cancerous lesions, HPV infection and HSV-2 infection.

Methods

Participants were 442 South African women of black African and mixed-ancestry origin with invasive cervical cancer and 278 control women matched by age, ethnicity and domicile status. FasR and FasL polymorphisms were genotyped by TaqMan and CASP8 polymorphism by PCR-RFLP. The results were analysed with R using haplo.stats software version 1.5.2.

Results

CASP8 -652 6 N del + FasR-670A was associated with a reduced risk (P = 0.019, Combined Polymorphism Score (CPS) = −2.34) and CASP8 -652 6 N ins + FasR-1377G was associated with a marginal increased risk (P = 0.047, CPS = 1.99) of cervical cancer among black Africans. When compared within the control group, CASP8 -652 6 N ins + FasR-1377A showed a reduced risk (P = 0.023, CPS = −2.28) of HSV-2 infection in both black African and mixed-ancestry population.

Conclusions

Our results show that the combined risks of variants in cell death pathway genes are associated with the cervical cancer as well as the HSV-2 infection in the black African and mixed-ancestry population.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1678-y) contains supplementary material, which is available to authorized users.

Pigment epithelial-derived factor (PEDF)-triggered lung cancer cell apoptosis relies on p53 protein-driven Fas ligand (Fas-L) up-regulation and Fas protein cell surface translocation

Pigment epithelium-derived factor (PEDF), a potent antiangiogenesis agent, has recently attracted attention for targeting tumor cells in several types of tumors. However, less is known about the apoptosis-inducing effect of PEDF on human lung cancer cells and the underlying molecular events. Here we report that PEDF has a growth-suppressive and proapoptotic effect on lung cancer xenografts. Accordingly, in vitro, PEDF apparently induced apoptosis in A549 and Calu-3 cells, predominantly via the Fas-L/Fas death signaling pathway. Interestingly, A549 and Calu-3 cells are insensitive to the Fas-L/Fas apoptosis pathway because of the low level of cell surface Fas. Our results revealed that, in addition to the enhancement of Fas-L expression, PEDF increased the sensitivity of A549 and Calu-3 cells to Fas-L-mediated apoptosis by triggering the translocation of Fas protein to the plasma membrane in a p53- and FAP-1-dependent manner. Similarly, the up-regulation of Fas-L by PEDF was also mediated by p53. Furthermore, peroxisome proliferator-activated receptor γ was determined to be the upstream regulator of p53. Together, these findings uncover a novel mechanism of tumor cell apoptosis induced by PEDF and provide a potential therapeutic strategy for tumors that are insensitive to Fas-L/Fas-dependent apoptosis because of a low level of cell surface Fas.

Association between the FAS rs2234767G/A polymorphism and cancer risk: a systematic review and meta-analysis

Abnormal regulation of apoptosis can lead to carcinogenesis. Single nucleotide polymorphisms in apoptotic genes have been associated with cancer risk, such as the FAS rs2234767G/A polymorphism, which alters transcription of the FAS promoter. Downregulation of FAS, with resultant cellular resistance to death signals, has been found in many cancers. However, the association between the FAS rs2234767G/A polymorphism and cancer risk is still controversial. Here, we performed a meta-analysis including 41 articles (44 case-control studies, 17,814 cases and 24,307 controls) identified from PubMed and Chinese language (CNKI and WanFang) databases related to cancer susceptibility and the FAS rs2234767G/A polymorphism. We used odds ratios (ORs) and 95% confidence intervals (CIs) to assess the strength of the associations. We found that the rs2234767 G-allele was a protective factor for cancer risk (GG vs. AA: OR=0.88, 95% CI=0.79-0.98; GG+GA vs. AA: OR=0.87, 95% CI=0.79-0.96). Similar associations were detected in the "source of control", ethnicity, and cancer type subgroups. Further studies on a larger sample size and considering gene-environment interactions should be conducted to confirm the role of FAS polymorphisms, especially rs2234767G/A, in cancer risk.

FAS-1377 G/A (rs2234767) polymorphism and cancer susceptibility: a meta-analysis of 17,858 cases and 24,311 controls

BACKGROUND AND OBJECTIVES

Disruption of apoptosis has been implicated in carcinogenesis. Specifically, various single-nucleotide polymorphisms (SNPs) in apoptotic genes, such as FAS-1377 G/A SNP, have been associated with cancer risk. FAS-1377 G/A SNP has been shown to alter FAS gene promoter transcriptional activity. Down-regulation of FAS and cell death resistance is key to many cancers, but an association between FAS-1377 G/A SNP and cancer risk is uncertain. Therefore, we conducted a meta-analysis of the current literature to clarify this relationship.

METHODOLOGY/PRINCIPAL FINDINGS

From PubMed and Chinese language (CNKI and WanFang) databases, we located articles published up to March 5, 2013, obtaining 44 case-control studies from 41 different articles containing 17,858 cases and 24,311 controls based on search criteria for cancer susceptibility related to the FAS gene -1377 G/A SNP. Odds ratios (ORs) and 95% confidence intervals (CI) revealed association strengths. Data show that the -1377 G allele was protective against cancer risk. Similar associations were detected in "source of control," ethnicity and cancer type subgroups. Lower cancer risk was found in both smokers with a GG+GA genotype and in non-smokers with the GG+GA genotype, when compared to smokers and nonsmokers with the AA genotype. Males carrying the -1377G allele (GG+GA) had lower cancer incidence than those with the AA genotype. Individuals who carried both FAS-1377(GG+GA)/FASL-844(TT+TC) genotypes appeared to have lower risk of cancer than those who carried both FAS-1377 AA/FASL-844 CC genotypes.

CONCLUSIONS/SIGNIFICANCE

The FAS-1377 G/A SNP may decrease cancer risk. Studies with larger samples to study gene-environment interactions are warranted to understand the role of FAS gene polymorphisms, especially -1377 G/A SNP, in cancer risk.

Functional polymorphisms in FAS/FASL system increase the risk of neuroblastoma in Chinese population

The FAS and FASL system plays a substantial role in apoptosis and immune escape of cells. Three polymorphisms located in the promoter regions of FAS (-1377G/A and -670A/G) and FASL (-844T/C) have been shown to alter the transcriptional activity of the genes, respectively. This study was conducted to evaluate the effects of these polymorphisms on the susceptibility of neuroblastoma in the Chinese population. A total of 203 patients with neuroblastoma and 411 controls were recruited in this case-control study. Polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP) was applied for genotyping. Unconditional logistic regression was used to estimate cancer risk by calculating odds ratios (ORs) and their 95% confidence intervals (95% CIs). It was observed that significantly increased risks of neuroblastoma associated with FAS -1377G/A and FASL -844T/C polymorphisms, with ORs equal to 1.55 (95% CI, 1.10–2.20) for FAS -1377 A allele and 2.90 (95% CI, 2.04–4.12) for FASL -844CC genotype carriers compared with non-carriers, respectively. However, no association was found between the polymorphisms of FAS -670A/G and risk of neuroblastoma. In addition, the cumulative effect of FAS and FASL polymorphisms on risk of neuroblastoma was observed (P for trend = 2.502×10⁻¹⁰), with OR for the carriers of both FAS -1377A allele and FASL -844CC genotypes equaled to 3.95 (95% CI, 2.40–6.51). This work reveals that polymorphisms of FAS -1377G/A and FASL -844T/C but not FAS -670A/G are associated with risk of neuroblastoma in Chinese. These findings support the hypothesis that genetic polymorphism in FAS/FASL death system may influence individual susceptibility to neuroblastoma.

FAS/FASL expression profile as a prognostic marker in squamous cell carcinoma of the oral cavity

FAS/FASL altered expression may cause tumor protecting immunomodulation, with a direct impact on patient prognosis. FAS expression was studied in 60 squamous cell carcinomas of the oral cavity. FAS expression did not show a significant association with tumor histopathological characteristics, but was significantly associated with lymph node positivity. FAS expression was significantly associated with disease specific death and negative FAS expression was an independent risk factor, increasing risk 4 times when compared to positive expression. When FAS and FASL expression results were combined, we were able to define high, intermediate and low risk profiles. Disease-free and disease-specific survival were significantly correlated with FAS/FASL expression profiles. The high risk category was an independent marker for earlier disease relapse and disease-specific death, with approximately 4- and 6-fold increased risk, respectively, when compared to the low risk profile. Risk profiles based on FAS/FASL expression showed that high risk was significantly associated with increased disease relapse and death, as well as shorter disease-free or disease-specific survival. This categorization, added to patient clinical data, may facilitate the choice of therapy, minimizing treatment failure and increasing disease control.

Mutational analysis of DNMT3A gene in acute leukemias and common solid cancers

DNMT3A, a DNA methyltransferase that functions for de novo methylation, is important in development and many cellular processes related to tumorigenesis. Somatic mutations of DNMT3A gene, including recurrent mutations in its Arg-882, were recently reported in acute myelogenous leukemia (AML), strongly suggesting its role in development of AML. To see whether DNMT3A mutation occurs in other malignancies as well, we analyzed DNMT3A in 916 cancer tissues from 401 hematologic malignancies (AML, acute lymphoblastic leukemias (ALL), multiple myelomas and lymphomas) and 515 carcinomas (lung, breast, prostate, colorectal and gastric carcinomas) using a single-strand conformation polymorphism (SSCP) assay. We identified DNMT3A mutations, especially the Arg-882 mutations, in adulthood AML (9.4%). In addition, we found DNMT3A mutations in pre-B-ALL and three lung cancers at lower frequencies. Allelic loss of DNMT3A was frequently observed in most cancer types analyzed, including lymphomas (48.1%), gastric cancers (23.5%) and lung cancers (18.3%) irrespective of DNMT3A mutation. Also, loss of DNMT3A expression was common in lung cancers (46.4%), and was associated with the allelic loss. Our data indicate that DNMT3A gene is mutated mainly in AML, but it occurs in other cancers, such as ALL and lung cancer, despite the lower incidences. Also, the data suggest that DNMT3A is altered in many cancer types by various ways, including somatic mutations, allelic loss and loss of expression that might play roles in tumorigenesis.

Using the theory of coevolution to predict protein-protein interactions in non-small cell lung cancer

Systems biology has become an effective approach for understanding the molecular mechanisms underlying the development of lung cancer. In this study, sequences of 100 non-small cell lung cancer (NSCLC)-related proteins were downloaded from the National Center for Biotechnology Information (NCBI) databases. The Theory of Coevolution was then used to build a protein-protein interaction (PPI) network of NSCLC. Adopting the reverse thinking approach, we analyzed the NSCLC proteins one at a time. Fifteen key proteins were identified and categorized into a special protein family F (K), which included Cyclin D1 (CCND1), E-cadherin (CDH1), Cyclin-dependent kinase inhibitor 2A (CDKN2A), chemokine (C-X-C motif) ligand 12 (CXCL12), epidermal growth factor (EGF), epidermal growth factor receptor (EGFR), TNF receptor superfamily, member 6 (FAS), FK506 binding protein 12-rapamycin associated protein 1 (FRAP1), O-6-methylguanine-DNA methyltransferase (MGMT), parkinson protein 2, E3 Ubiquitin protein ligase (PARK2), phosphatase and tensin homolog (PTEN), calcium channel voltage-dependent alpha 2/delta subunit 2 (CACNA2D2), tubulin beta class I (TUBB), SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily a, member 2 (SMARCA2), and wingless-type MMTV integration site family, member 7A (WNT7A). Seven key nodes of the sub-network were identified, which included PARK2, WNT7A, SMARCA2, FRAP1, CDKN2A, CCND1, and EGFR. The PPI predictions of EGFR-EGF, PARK2-FAS, PTEN-FAS, and CACNA2D2-CDH1 were confirmed experimentally by retrieving the Biological General Repository for Interaction Datasets (BioGRID) and PubMed databases. We proposed that the 7 proteins could serve as potential diagnostic molecular markers for NSCLC. In accordance with the developmental mode of lung cancer established by Sekine et al., we assumed that the occurrence and development of lung cancer were linked not only to gene loss in the 3p region (WNT7A, 3p25) and genetic mutations in the 9p region but also to similar events in the regions of 1p36.2 (FRAP1), 6q25.2-q27 (PARK2), and 11q13 (CCND1). Lastly, the invasion or metastasis of lung cancer happened.

Autophagy Mechanism, Regulation, Functions, and Disorders

Autophagy is a self-digesting mechanism responsible for removal of damaged organelles, malformed proteins during biosynthesis, and nonfunctional long-lived proteins by lysosome. Autophagy has been divided into three general types depending on the mechanism by which intracellular materials are delivered into lysosome for degradation that is, microautophagy, chaperone-mediated autophagy (CMA), and macroautophagy. In microautophagy cytoplasm material is sequestered through direct invagination to the lysosomal membrane. Whereas in CMA proteins flagged with pentapeptide motif (KFERQ) were selectively degraded through direct translocation into lysosome. Macroautophagy involves the formation of subcellular double-membrane-bound structures called autophagosomes that contain degradable contents of cytoplasm materials and deliver them into lysosomes for breakdown by lysosomal enzymes. The molecular mechanism of autophagy involves several conserved Atg (autophagy-related) proteins. Systems produce modified complexes Atg8-PE and Atg5-Atg12-Atg16 as autophagy regulators. Autophagy is activated in response to diverse stress and physiological conditions. For example, food deprivation, hyperthermia, and hypoxia are mediated by factors like insulin/IGF-1, m-TOR signaling, FOXO transcription factors, and chaperones. The perturbance in autophagy may lead to several types of cancers, myopathies, and neuromuscular disorders. Several autophagy inducers and inhibitors like 3-methyladenine (3-MA), bafilomycin A1, LY294002 (LY), and Velcade have been used to treat disease is an intense field of study.

Mutational analysis of tumour suppressor gene NF2 in common solid cancers and acute leukaemias

AIMS

Germline mutation of NF2 gene is a feature of neurofibromatosis type 2 familial cancer syndrome. Also, somatic point mutations of NF2 mutation have been reported in tumours originated from nerve structures. A recent study revealed that NF2 gene was mutated in renal cell carcinoma (RCC) as well, suggesting a possibility that NF2 gene might be somatically mutated in other human cancers. The aim of this study was to explore whether NF2 genes are somatically mutated, and contribute to tumorigenesis in common human cancers.

METHODS

For this, we analysed the entire coding region of NF2 gene in 45 colorectal carcinomas, 45 gastric, 45 breast, 45 lung, 45 hepatocellular (HCC), 45 prostate carcinomas, and 45 acute leukaemias by a single-strand conformation polymorphism assay.

RESULTS

Overall, we found NF2 mutations in one HCC (1/45; 2.2%) (hepatitis B virus-related HCC), one lung carcinoma (1/45; 2.2%) (squamous cell carcinoma), and one acute leukaemia (1/45; 2.2%) (acute myelogenous leukaemia minimally differentiated). All of the mutations were missense mutations that would substitute amino acids in the NF2 protein (p.A238 V, p.A451T and p.R467K).

CONCLUSION

Our data indicate that somatic mutation of NF2 gene is not prevalent in common human cancers, and its mutation somatically occurs in a minor fraction of HCC, lung cancer and acute leukaemia. These data suggest that somatic mutation of NF2 tumour suppressor gene may not play a central role in development of common cancers.

Mutational analysis of PIK3CA, JAK2, BRAF, FOXL2, IDH1, AKT1 and EZH2 oncogenes in sarcomas

Recent studies have revealed several recurrent mutations in oncogenes that could not only be underlying mechanisms of tumorigenesis, but also be potential targets for cancer therapies. Compared to carcinomas, genetic alterations of sarcomas are relatively unknown. To see whether recurrent oncogenes discovered in non-sarcomatous malignancies are present in sarcomas as well, we analyzed oncogenes with known mutations in various types of sarcomas. We performed mutational analysis of recurrent mutation sites of PIK3CA (exons 9 and 20), JAK2 (exon 14), BRAF (exon 15), FOXL2 (exon 1), IDH1 (exon 4), AKT1 (exon 3), and EZH2 (exon 16) genes in 108 sarcomas by single- strand conformation polymorphism and DNA sequencing. The sarcomas consisted of malignant fibrous histiocytomas, rhabdomyosarcomas, osteosarcomas, malignant peripheral nerve sheath tumors, leiomyosarcomas, synovial sarcomas, liposarcomas, angiosarcomas, chondrosarcomas, and Ewing sarcomas. Overall, we detected the two PIK3CA mutations and one JAK2 mutation (total: 3/108: 2.8%). Two rhabdomyosarcomas (16.7%) and one angiosarcoma (16.7%) harbored the mutations, whereas other sarcomas harbored none. The PIK3CA mutations were novel missense mutations that had not been detected in other cancers. The JAK2 mutation was an intron mutation. This study demonstrated that the somatic mutations of PIK3CA and JAK2 occurred in a small fraction of the sarcomas and that these mutations may not play a principal role in the development of sarcomas.

Somatic mutations of the KEAP1 gene in common solid cancers

AIMS

KEAP1 inhibits nuclear factor erythroid 2-related factor 2 (NRF2)-induced cytoprotection, and is considered to be a candidate tumour suppressor. Somatic mutation of NRF2 has been analysed in a wide variety of human cancers, whereas somatic mutation of KEAP1 has been reported only in lung and gall bladder cancers. The aim of our study was to investigate whether KEAP1 mutations are widespread in human cancers.

METHODS AND RESULTS

We analysed 499 cancer tissues from lung, breast, colon, stomach, liver, larynx and prostate, and leukaemias, by single-strand conformation polymorphism analysis. We detected somatic mutations of KEAP1 in gastric (11.1%), hepatocellular (8.9%), colorectal (7.8%), lung (4.6%), breast (2.0%) and prostate (1.3%) carcinomas. Allelic losses of the KEAP1 locus were identified in 42.9% of cancers with KEAP1 mutations, but no NRF2 mutations were detected in these cancers. The NRF2-activated cytoprotective proteins (NAD(P)H dehydrogenase quinone 1 and glutamine-cysteine ligase catalytic subunit) were expressed in all of the cancers with KEAP1 mutations.

CONCLUSIONS

Our data show that KEAP1 mutations occur widely in solid cancers, irrespective of histological type. Biallelic inactivation of KEAP1 and increased levels of cytoprotective proteins in the cancers suggest that KEAP1 mutations might protect cancer cells from oxidative insults and play a role in the development of solid cancers.

Somatic mutation of PHF6 gene in T-cell acute lymphoblatic leukemia, acute myelogenous leukemia and hepatocellular carcinoma

INTRODUCTION

Somatic mutations in plant homeodomain finger protein 6 (PHF6) gene have recently been reported in T-cell acute lymphoblastic leukemia (T-ALL), strongly suggesting its role in the pathogenesis of human cancers.

MATERIALS AND METHODS

To see whether the PHF6 mutation occurs in other malignancies, we analyzed entire coding sequences of PHF6 in 231 hematologic malignancies [105 acute myelogenous leukemias (AML), 66 pre-B-ALL, 23 T-ALL, one undifferentiated acute leukemia and 36 multiple myelomas] by single-strand conformation polymorphism assay. Also, we analyzed the mutation in 236 solid cancers, including 41 lung, 39 hepatocellular (HCC), 36 breast, 40 colorectal, 40 gastric and 40 prostate carcinomas.

RESULTS

In the hematologic malignancies, there were 11 PHF6 mutations that were detected not only in T-ALL (34.7%) (five adult and three childhood T-ALL), but also in two AML (1.9%) (one acute monocytic leukemia and one AML minimally differentiated). In addition, there was a PHF6 mutation in the HCC (2.6%). The PHF6 mutations were detected in both male and female patients, and consisted of six frameshift, three nonsense and two intron mutations.

CONCLUSION

Our data suggest that PHF6 mutation might play a role in tumorigenesis not only of T-ALL, but also of AML and HCC.

Somatic mutations of caspase-2 gene in gastric and colorectal cancers

There is mounting evidence that evasion of apoptosis is a hallmark of cancer. Caspase-2, which plays roles in both extrinsic and intrinsic apoptosis pathways, is considered a candidate tumor suppressor. The aim of this study was to explore the possibility that genetic alterations of caspase-2 gene are present in human cancers. In this study, we analyzed the entire coding sequences of human caspase-2 gene for the detection of somatic point mutations in 90 gastric carcinomas and 100 colorectal carcinomas by polymerase chain reaction (PCR)-single strand conformation polymorphism (SSCP). Of the cancers analyzed, two gastric cancers (2/90; 2.2%) and two colorectal cancers (2/100; 2.0%) harbored somatic missense mutations of caspase-2. The mutations consisted of p.V46M (at prodomain), p.S157L (at prodomain), p.R357K (at p13 subunit), and p.R397L (at p13 subunit). We expressed these tumor-derived mutants in 293 T cells and found that three of the mutants decreased cell death activity of caspase-2. Our data indicate that somatic mutation of caspase-2 is rare in gastric and colorectal carcinomas. However, functional data of the caspase-2 mutations also suggest that caspase-2 gene mutation might affect the pathogenesis of some gastric and colorectal cancers by inactivating cell death function of caspase-2.

Mutational and expressional analyses of ATG5, an autophagy-related gene, in gastrointestinal cancers

There is mounting evidence that alterations of cell death processes are involved in cancer pathogenesis. ATG5 is a key regulator of autophagic and apoptotic cell death. The aim of this study was to see whether alterations of ATG5 protein expression and somatic mutation of ATG5 gene are features of human gastrointestinal cancers. In this study, we analyzed ATG5 somatic mutation in 45 gastric, 45 colorectal, and 45 hepatocellular carcinomas by single-strand conformation polymorphism (SSCP). Also, we analyzed ATG5 protein expression in 100 gastric, as well as in 95 colorectal and hepatocellular carcinomas using immunohistochemistry. Overall, we detected two somatic missense mutations of ATG5 gene in the coding sequences p.Leu112Phe and p.His41Tyr. The mutations were observed in one gastric and one hepatocellular carcinoma. Immunohistochemically, ATG5 protein was well expressed in normal stomach, colon, and liver epithelial cells, while it was lost in 21 (21%) of the gastric carcinomas, in 22 (23%) of the colorectal carcinomas, and in 5 (10%) of the hepatocellular carcinomas. Our data suggest that ATG5 gene could be altered in gastrointestinal cancers at the mutational or expressional level. Despite the low incidences of the alterations, our data led us to conclude that somatic mutation and loss of expression of ATG5 gene might play a role in gastrointestinal cancer pathogenesis by altering autophagic and apoptotic cell death.

Genetic and expressional alterations of CHD genes in gastric and colorectal cancers

AIMS

Chromodomain helicase DNA-binding protein (CHD) is a regulator of the chromatin remodelling process. The aim was to determine the CHD1, CHD2, CHD3, CHD4, CHD7, CHD8 and CHD9 mutational status of mononucleotide repeats in gastric and colorectal cancers with microsatellite instability (MSI).

METHODS AND RESULTS

The repeats were determined in 28 gastric cancers (GCs) with high MSI (MSI-H), 45 GCs with low MSI (MSI-L)/stable MSI (MSS), 35 colorectal cancers (CRCs) with MSI-H and 45 CRCs with MSI-L/MSS by single-strand conformation polymorphism analysis. CHD4 and CHD8 expression was also examined in GCs and CRCs by immunohistochemistry. CHD1, CHD2, CHD3, CHD4, CHD7, CHD8 and CHD9 mutations were found in five, 19, three, five, seven, 10 and seven cancers, respectively. They were detected in MSI-H cancers, but not in MSI-L/MSS cancers. Loss of CHD4 expression was observed in 56.4% of the GCs and 55.7% of the CRCs, and loss of CHD8 was observed in 35.7% of the GCs and 28.6% of the CRCs. The cancers with CHD4 and CHD8 mutations showed loss of CHD4 and CHD8 expression, respectively.

CONCLUSIONS

Frameshift mutation and loss of expression of CHD genes are common in GCs and CRCs with MSI-H.These alterations might contribute to cancer pathogenesis by deregulating CHD-mediated chromatin remodelling.

Fas and FasL polymorphisms are not associated with acute myeloid leukemia risk in Koreans

Fas and Fas ligand (FasL) polymorphisms in the promoter regions influence transcriptional activities. The interaction of these two genes plays a crucial role in apoptotic cell death regulation. They have been associated with esophageal, lung, uterine cervical, and urinary bladder cancers in human. We performed a case-control study to investigate the association between Fas and FasL polymorphisms and acute myeloid leukemia (AML) risk. Fas−1377G>A (rs2234767), −670T>C (rs1800682), and FasL−844T>C (rs763110) polymorphisms in 592 AML patients and 858 healthy controls were genotyped and tested for associations between polymorphisms and AML risk. There were no significant differences in genotypic and haplotypic distributions and gene-gene interaction between patients and controls in the overall analysis (p>0.05). These results suggested that polymorphisms of Fas and FasL genes were not associated with AML risk in the Korean population.

Somatic frameshift mutations of bone morphogenic protein receptor 2 gene in gastric and colorectal cancers with microsatellite instability

Mounting evidence exists that perturbation of bone morphogenic protein (BMP) signaling is involved in cancer development, especially in gastrointestinal cancers. However, somatic mutations of the genes encoding BMP and BMP receptors have not yet been discovered in human cancer tissues. By analyzing a public database, we found that BMP receptor 2 (BMPR2) and BMP1 genes had mononucleotide repeats in their coding sequences that could be mutation targets in cancers with microsatellite instability (MSI). In this study, we analyzed the mutation of BMPR2 and BMP1 genes in gastric (GC) and colorectal cancers (CRC) with MSI [31 GC with high MSI (MSI-H), 13 GC with low MSI (MSI-L), 38 CRC with MSI-H and 15 CRC with MSI-L] by single-strand conformation polymorphism analysis and DNA sequencing. Overall, we found seven frameshift mutations in the BMPR2 gene, but not in the BMP1 gene. The mutations were an identical deletion mutation of one base in the repeats (c.1748delA) that would result in premature stops of the amino acid synthesis (p.Asn583ThrfsX44). The BMPR2 mutations were detected in 6.5% of GC and 13.2% of CRC with MSI-H. All the cancers with the BMPR2 mutation showed loss of BMPR2 expression. Our data indicate that frameshift mutation of BMPR2 gene occurs in GC and CRC with MSI-H, and suggest that the BMPR2 mutation might contribute to cancer pathogenesis by inactivating BMPR2-mediated BMP signaling.