Polymorphisms and haplotypes in the caspase-3, caspase-7, and caspase-8 genes and risk for endometrial cancer: a population-based, case-control study in a Chinese population

A Review on Caspases: Key Regulators of Biological Activities and Apoptosis

Caspases are proteolytic enzymes that belong to the cysteine protease family and play a crucial role in homeostasis and programmed cell death. Caspases have been broadly classified by their known roles in apoptosis (caspase-3, caspase-6, caspase-7, caspase-8, and caspase-9 in mammals) and in inflammation (caspase-1, caspase-4, caspase-5, and caspase-12 in humans, and caspase-1, caspase-11, and caspase-12 in mice). Caspases involved in apoptosis have been subclassified by their mechanism of action as either initiator caspases (caspase-8 and caspase-9) or executioner caspases (caspase-3, caspase-6, and caspase-7). Caspases that participate in apoptosis are inhibited by proteins known as inhibitors of apoptosis (IAPs). In addition to apoptosis, caspases play a role in necroptosis, pyroptosis, and autophagy, which are non-apoptotic cell death processes. Dysregulation of caspases features prominently in many human diseases, including cancer, autoimmunity, and neurodegenerative disorders, and increasing evidence shows that altering caspase activity can confer therapeutic benefits. This review covers the different types of caspases, their functions, and their physiological and biological activities and roles in different organisms.

Effective smMIPs-Based Sequencing of Maculopathy-Associated Genes in Stargardt Disease Cases and Allied Maculopathies from the UK

Macular dystrophies are a group of individually rare but collectively common inherited retinal dystrophies characterised by central vision loss and loss of visual acuity. Single molecule Molecular Inversion Probes (smMIPs) have proved effective in identifying genetic variants causing macular dystrophy. Here, a previously established smMIPs panel tailored for genes associated with macular diseases has been used to examine 57 UK macular dystrophy cases, achieving a high solve rate of 63.2% (36/57). Among 27 bi-allelic STGD1 cases, only three novel ABCA4 variants were identified, illustrating that the majority of ABCA4 variants in Caucasian STGD1 cases are currently known. We examined cases with ABCA4-associated disease in detail, comparing our results with a previously reported variant grading system, and found this model to be accurate and clinically useful. In this study, we showed that ABCA4-associated disease could be distinguished from other forms of macular dystrophy based on clinical evaluation in the majority of cases (34/36).

Mutational analysis of apoptotic genes in familial aggregation of hematological malignancies

INTRODUCTION

Apoptosis deregulation have been associated to tumorigenesis process and was highlighted as a prominent hallmark of cancer. Several mutations have been reported in several forms of Blood cancer. However, it has never been investigated in familial aggregations of hematological malignancies.

METHODS

In this study, we performed a mutational analysis by sequencing the entire coding regions in four key apoptotic genes FAS, FASLG, CASP8 and CASP10 in 92 independent families belonging to French and Tunisian populations and diagnosed with several forms of familial hematological malignancies.

RESULTS

We report 15 genetic variations among which 7 were previously reported in several form of cancers and have a potential effect on gene expression. Particularly, the CASP8 variants p.Asp302His and p.Lys337Lys were detected in 15% and 10% of our group of patients respectively and were previously reported in association to breast cancer and to breast cancer susceptibility.

DISCUSSION

In this study, we do not report the underlining deleterious mutations in familial hematological malignancies, but we describe some variants with potential risk of developing blood cancer. To gain further insights on the association between apoptosis pathway deregulation and familial hematological malignancies, more apoptotic genes should be investigated.

The Relevance of SNPs at 3'UTR Region of CASP7 and miR-371b-5p Associated Diseases: A Computational Analysis

The process of genetically programmed cell death, or apoptosis, plays a crucialrolein cellular homeostasis and gene expression. Disruption of apoptosis may lead to aberrant immune responses, cancer, and neurodegenerative diseases. Single nucleotide polymorphisms (SNPs) present in various microRNA (miRNA) genes and targets being an alteration of miRNA activity resulting in human diseases. Evidence reported that SNPs increase/decrease the effectiveness of the interaction between miRNAs and their target genes associated with diseases. The primary purpose of this study is not only to identify miRSNPs on the CASP7 gene (caspase-7) and SNPs in miRNA genes targeting 3'UTR but also to evaluate the effect of thesegene variations in apoptosis and their associated diseases. We detected 120 miRNAs binding sites and 27 different SNPs in binding sites of miRNA in 3'UTR of the CASP7 gene by ten different online softwares. Interestingly, miR-371b-5p's binding site on CASP7 has an SNP (rs576198588, G/T) on CASP7 3'UTR, and its genomic sequence has an SNP (rs751339395, G/T) at the same nucleotide with rs576198588. Similarly, two other SNPs (rs774879764, C/G rs750389063, C/T) were identified at the first position binding site of miR-371b-5p. Here, miRSNP (rs576198588) at CASP7 3'UTR and SNP (rs751339395) at miR-371b-5p genomic sequence cross-matches at the same site of binding region. Besides, miR-371b-5p targets many apoptosis-related genes (HIP1, TRIAP1, GSKIP, NIN, DAP, CAAP1, XIAP, TMBIM1, TMBIM4, TNFRSF10A, RAD21, AKT1, BAG1, BAG4) even though it had no apoptosis correlated interaction demonstrated formerly. It assures that CASP7 could have a significant consequence on apoptosis through different pathways. Henceforth, this study was representing and signifying an influential connotation among miR-371b-5p and apoptosis via computational exploration and recommended to have better insight.

Therapeutic effect of metformin in the treatment of endometrial cancer

The present review aims at reviewing the role of metformin in the treatment of endometrial cancer (EC). According to the literature, excessive estrogen levels and insulin resistance are established risk factors of EC. As a traditional insulin sensitizer and newly discovered anticancer agent, metformin directly and indirectly inhibits the development of EC. The direct mechanisms of metformin include inhibition of the LKB1-AMP-activated protein kinase-mTOR, PI3K-Akt and insulin-like growth factor 1-related signaling pathways, which reduces the proliferation and promotes the apoptosis of EC cells. In the indirect mechanism, metformin increases the insulin sensitivity of body tissues and decreases circulating insulin levels. Decreased levels of insulin increase the blood levels of sex hormone binding globulin, which leads to reductions in circulating estrogen and androgens. The aforementioned findings suggest that metformin serves an important role in the treatment of EC. Increased understanding of the mechanism of metformin in EC may provide novel insights into the treatment of this malignancy.

Initiator and executioner caspases in salivary gland apoptosis of Rhipicephalus haemaphysaloides

Background

Apoptosis is fundamental in maintaining cell balance in multicellular organisms, and caspases play a crucial role in apoptosis pathways. It is reported that apoptosis plays an important role in tick salivary gland degeneration. Several different caspases have been found in ticks, but the interactions between them are currently unknown. Here, we report three new caspases, isolated from the salivary glands of the tick Rhipicephalus haemaphysaloides.

Methods

The full-length cDNA of the RhCaspases 7, 8 and 9 genes were obtained by transcriptome, and RhCaspases 7, 8 and 9 were expressed in E. coli; after protein purification and immunization in mice, specific polyclonal antibodies (PcAb) were created in response to the recombinant protein. Reverse-transcription quantitative PCR (RT-qPCR) and western blot were used to detect the existence of RhCaspases 7, 8 and 9 in ticks. TUNEL assays were used to determine the apoptosis level in salivary glands at different feeding times after gene silencing. The interaction between RhCaspases 7, 8 and 9 were identified by co-transfection assays.

Results

The transcription of apoptosis-related genes in R. haemaphysaloides salivary glands increased significantly after tick engorgement. Three caspase-like molecules containing conserved caspase domains were identified and named RhCaspases 7, 8 and 9. RhCaspase8 and RhCaspase9 contain a long pro-domain at their N-terminals. An RT-qPCR assay demonstrated that the transcription of these three caspase genes increased significantly during the engorged periods of the tick developmental stages (engorged larval, nymph, and adult female ticks). Transcriptional levels of RhCaspases 7, 8 and 9 in salivary glands increased more significantly than other tissues post-engorgement. RhCaspase9-RNAi treatment significantly inhibited tick feeding. In contrast, knockdown of RhCaspase7 and RhCaspase8 had no influence on tick feeding. Compared to the control group, apoptosis levels were significantly reduced after interfering with RhCaspase 7, 8 and 9 expressions. Co-transfection assays showed RhCaspase7 was cleaved by RhCaspases 8 and 9, demonstrating that RhCaspases 8 and 9 are initiator caspases and RhCaspase7 is an executioner caspase.

Conclusions

To the best of our knowledge, this is the first study to identify initiator and executioner caspases in ticks, confirm the interaction among them, and associate caspase activation with tick salivary gland degeneration.

Endometrial carcinoma-related genetic factors: application to research and clinical practice in China

Genetic factors affect the initiation and progression of endometrial carcinoma (EC). The routine detection of genetic factors involved in EC has not been extensively performed in Chinese clinical practice, however. In this review we summarise EC-related genetic factors, including Lynch syndrome-associated mutations and non-Lynch syndrome-associated genetic predispositions found in Chinese women, and their potential clinical applications. In addition, we propose a clinical testing strategy for patients with EC and their family members. The objective of this review is to advance basic research regarding the genetic factors involved in EC and to improve its clinical implementation in China.

TWEETABLE ABSTRACT

Review summarises Chinese research progression of EC-related genetic factors and proposes innovative screening strategy.

MicroRNA-210-mediated proliferation, survival, and angiogenesis promote cardiac repair post myocardial infarction in rodents

An innovative approach for cardiac regeneration following injury is to induce endogenous cardiomyocyte (CM) cell cycle re-entry. In the present study, CMs from adult rat hearts were isolated and transfected with cel-miR-67 (control) and rno-miR-210. A significant increase in CM proliferation and mono-nucleation were observed in miR-210 group, in addition to a reduction in CM size, multi-nucleation, and cell death. When compared to control, β-catenin and Bcl-2 were upregulated while APC (adenomatous polyposis coli), p16, and caspase-3 were downregulated in miR-210 group. In silico analysis predicted cell cycle inhibitor, APC, as a direct target of miR-210 in rodents. Moreover, compared to control, a significant increase in CM survival and proliferation were observed with siRNA-mediated inhibition of APC. Furthermore, miR-210 overexpressing C57BL/6 mice (210-TG) were used for short-term ischemia/reperfusion study, revealing smaller cell size, increased mono-nucleation, decreased multi-nucleation, and increased CM proliferation in 210-TG hearts in contrast to wild-type (NTG). Likewise, myocardial infarction (MI) was created in adult mice, echocardiography was performed, and the hearts were harvested for immunohistochemistry and molecular studies. Compared to NTG, 210-TG hearts showed a significant increase in CM proliferation, reduced apoptosis, upregulated angiogenesis, reduced infarct size, and overall improvement in cardiac function following MI. β-catenin, Bcl-2, and VEGF (vascular endothelial growth factor) were upregulated while APC, p16, and caspase-3 were downregulated in 210-TG hearts. Overall, constitutive overexpression of miR-210 rescues heart function following cardiac injury in adult mice via promoting CM proliferation, cell survival, and angiogenesis.

KEY MESSAGES

MiRNA-210 transfected adult rat CMs show proliferation and reduced cell death in vitro. Cell cycle inhibitor APC is a target of miR-210. MiR-210 overexpressing (210-TG) mouse hearts show CMs cell cycle re-entry and survival post myocardial injury. 210-TG mice show significant neovascularization and angiogenic potential post myocardial infarction. 210-TG hearts show reduced infarct size following ischemic injury.

Apoptosis‑independent cleavage of RhoGDIβ at Asp19 during PMA‑stimulated differentiation of THP‑1 cells to macrophages

Rho GDP-dissociation inhibitor β (RhoGDIβ), a regulator of the Rho family of proteins, is expressed abundantly in the hematopoietic cell lineage. During apoptosis of hematopoietic cells, RhoGDIβ is cleaved by caspase-3 at Asp19 and this cleaved form (Δ19-RhoGDIβ) has been implicated in the apoptotic pathway. To clarify the role of RhoGDIβ in hematopoietic cells, the present study performed immunoblotting and immunofluorescence staining to examine the expression of RhoGDIβ and ∆19-RhoGDIβ during phorbol 12-myristate 13-acetate (PMA)-stimulated differentiation of human THP-1 monocytic cells to macrophages. During differentiation of the THP-1 cells to macrophages, the expression of RhoGDIβ remained stable; however, the expression of Δ19-RhoGDIβ increased, particularly in well-spreading, non-apoptotic cells, which differentiated into macrophages. These results suggested that Δ19-RhoGDIβ has an apoptosis-independent role in the PMA-induced differentiation of THP-1 cells to macrophages.

Associations of Caspase-3 gene polymorphism with lumbar disc herniation

To investigate Caspase-3 gene polymorphisms (rs4647693 G/A, rs4647610 A/G, and rs12108497 T/C) and susceptibility to lumbar intervertebral disc herniation (LDH). The genotype frequency distributions of the polymorphisms were detected by polymerase chain reaction-restriction fragment length polymorphism in 107 LDH patients (case group) and 121 healthy individuals (control group). SHEsis software was used to conduct gene linkage disequilibrium and haplotype analysis. Regression analysis was used to analyze possible risk factors for LDH. Statistically significant differences in family history of LDH, amateur sports, leisure activities, bed types, and spine load grade were found between the case and control groups. The distribution of allele and genotype frequencies of rs4647693 G/A, rs4647610 A/G, and rs12108497 T/C polymorphisms of Caspase-3 were significantly different between the case and control groups. Haplotype analysis showed that the G-G-C (rs4647693-rs4647610-rs12108497) haplotype might be a risk factor for LDH, whereas the A-A-T haplotype might be a protective factor (p < 0.05). Binary logistic regression analysis showed that the GA+AA genotype of rs4647693 was negatively associated with the risk of LDH, whereas high spine load grade was positively associated with the risk of LDH. These findings revealed that rs4647693 G/A, rs4647610 A/G, and rs12108497 T/C polymorphisms of Caspase-3 may be associated with susceptibility to LDH and that interaction and modification effects may exist between Caspase-3 polymorphisms.

Genetic Polymorphisms in the Apoptosis-Associated Gene CASP3 and the Risk of Lung Cancer in Chinese Population

Caspase-3 (CASP3) plays a central role in executing cell apoptosis and thus in carcinogenesis. We previously investigated the relationship between functional polymorphisms in CAPS3 829 A>C and 20541 C>T and risk of esophageal squamous cell carcinoma. However little is known about the role of CASP3 variants in susceptibility to lung cancer. To figure out the contribution of CASP3 polymorphisms to lung cancer risk, genotypes of 1000 lung cancer patients and 1000 controls were conducted by RFLP-PCR (restriction fragment length polymorphism PCR). The transcriptional activity of CASP3 829 A>C was examined by dual luciferase reporter assay. Logistic regression was applied to calculate Odds ratios (OR) and 95% confidence intervals (95%CI). Compared with CASP3 829 AA genotype, AC and CC genotype had significantly increased risk of lung cancer with OR (95% CI) of 1.33 (1.09–1.63) and 1.55 (1.19–2.01), respectively. To further explore the possible impact of 829 A>C SNP on CASP3 transcriptional activity, we detected the dual luciferase activity of PGL3-promoter vectors containing 829A or 829C alleles in lung cancer cell lines and found that report gene expressions driven by 829A containing CASP3 promoter were 1.64-fold, 1.94-fold greater than those driven by CASP3 829C containing counterparts in A549 and NCI-H1975 cells (P<0.001). When stratified by sex, the significantly increased risk associated with CASP3 829 AC or CC genotype was obviousl in males with OR (95% CI) of 1.42 (1.11–1.81) and 1.51 (1.11–2.05), but not in females. When stratified by age, we found that CASP3 829 AC or CC genotype contributed to the risk of lung cancer in youngers with OR (95% CI) of 2.73 (1.71–4.34) and 4.02 (2.20–7.32), but not in elder group. We also found that 829AC or 829CC genotype increased adenocarcinoma risk compared with the AA genotype with OR (95%CI) of 1.33 (1.04–1.70) and 1.51(1.09–2.07). CASP3 polymorphism and smoking interaction was demonstrated related with higher risk of lung cancer. We achieved that the CASP3 829AC or 829CC genotypes was associated with increased risk of lung cancer in both non-smoker and smoker group, with OR (95%CI) of 1.48 (1.08–2.02) and OR (95%CI) of 1.64 (1.09–2.48) among non-smokers and OR (95%CI) of 2.68 (1.89–3.81) and OR (95%CI) of 3.23 (2.21–4.92) among smokers, respectively. Among carriers with 20541CT genotype, the ORs (95%CI) of risk with lung cancer for smoking <16, 16–28, or > 28 pack-years were 1.16(0.65–2.07), 1.66(0.98–2.82) and 5.01(3.31–7.58) compared with the 20541CC carriers. And among carriers with 20541CT genotype, the ORs (95%CI) were 0.86(0.33–2.20), 2.12(0.83–5.41) and 5.71(2.68–12.16). These results highlight apoptosis-related CASP3 as an important gene in human carcinogenesis and further support the CASP3 polymorphisms confer to the lung cancer susceptibility.

Prognostic and Predictive Value of DAMPs and DAMP-Associated Processes in Cancer

It is now clear that human neoplasms form, progress, and respond to therapy in the context of an intimate crosstalk with the host immune system. In particular, accumulating evidence demonstrates that the efficacy of most, if not all, chemo- and radiotherapeutic agents commonly employed in the clinic critically depends on the (re)activation of tumor-targeting immune responses. One of the mechanisms whereby conventional chemotherapeutics, targeted anticancer agents, and radiotherapy can provoke a therapeutically relevant, adaptive immune response against malignant cells is commonly known as “immunogenic cell death.” Importantly, dying cancer cells are perceived as immunogenic only when they emit a set of immunostimulatory signals upon the activation of intracellular stress response pathways. The emission of these signals, which are generally referred to as “damage-associated molecular patterns” (DAMPs), may therefore predict whether patients will respond to chemotherapy or not, at least in some settings. Here, we review clinical data indicating that DAMPs and DAMP-associated stress responses might have prognostic or predictive value for cancer patients.

Old, new and emerging functions of caspases

Caspases are proteases with a well-defined role in apoptosis. However, increasing evidence indicates multiple functions of caspases outside apoptosis. Caspase-1 and caspase-11 have roles in inflammation and mediating inflammatory cell death by pyroptosis. Similarly, caspase-8 has dual role in cell death, mediating both receptor-mediated apoptosis and in its absence, necroptosis. Caspase-8 also functions in maintenance and homeostasis of the adult T-cell population. Caspase-3 has important roles in tissue differentiation, regeneration and neural development in ways that are distinct and do not involve any apoptotic activity. Several other caspases have demonstrated anti-tumor roles. Notable among them are caspase-2, -8 and -14. However, increased caspase-2 and -8 expression in certain types of tumor has also been linked to promoting tumorigenesis. Increased levels of caspase-3 in tumor cells causes apoptosis and secretion of paracrine factors that promotes compensatory proliferation in surrounding normal tissues, tumor cell repopulation and presents a barrier for effective therapeutic strategies. Besides this caspase-2 has emerged as a unique caspase with potential roles in maintaining genomic stability, metabolism, autophagy and aging. The present review focuses on some of these less studied and emerging functions of mammalian caspases.

Association of BH3 interacting domain death agonist (BID) gene polymorphisms with proteinuria of immunoglobulin A nephropathy

BACKGROUND

Apoptosis plays an important role in the mechanism regulating the development of glomerulonephritis. We investigated whether polymorphisms of apoptotic genes such as B-cell CLL/lymphoma 2 (BCL2), BH3-interacting domain death agonist (BID), and caspase 8 (CASP8) were associated with immunoglobulin A nephropathy (IgAN) and with the clinical phenotypes of IgAN patients.

METHODS

We genotyped promoter and coding region single nucleotide polymorphisms (SNPs) (rs2279115 and rs1801018 for BCL2; rs8190315 and rs2072392 for BID; and rs6747918 and rs1045487 for CASP8) using direct sequencing in 195 IgAN patients and 289 control subjects.

RESULTS

No SNPs were associated with IgAN. However, in analysis of clinical phenotypes, we found that rs8190315 and rs2072392 of BID were associated with proteinuria levels of IgAN patients in additive (AG vs. GG vs. AA, p = 0.0008 for rs8190315; TC vs. CC vs. TT, p = 0.0012 for rs2072392) and dominant models (AG/GG vs. AA, p = 0.0014 for rs8190315; TC/CC vs. TT, p = 0.0031 for rs2072392). In particular, the frequencies of genotypes containing minor alleles of rs8190315 (G allele) and rs2072392 (C allele) were increased in IgAN patients with higher protienuria levels (> 40 mg/m(2)/h).

CONCLUSION

These results suggest that BID may play a role in severe IgAN.

Association of genetic markers in the BCL-2 family of apoptosis-related genes with endometrial cancer risk in a Chinese population

Background

In vitro studies have demonstrated the role of the BCL-2 family of genes in endometrial carcinogenesis. The role of genetic variants in BCL-2 genes and their interactions with non-genetic factors in the development of endometrial cancer has not been investigated in epidemiological studies.

Patients and Methods

We examined the relationship between BCL-2 gene family variants and endometrial cancer risk among 1,028 patients and 1,922 age-matched community controls from Shanghai, China. We also investigated possible interactions between genetic variants and established risk factors (demographic, lifestyle and clinical). Individuals were genotyped for 86 tagging single nucleotide polymorphisms (SNPs) in the BCL2, BAX, BAD and BAK1 genes.

Results

Significant associations with endometrial cancer risk were found for 9 SNPs in the BCL2 gene (P trend<0.05 for all). For SNPs rs17759659 and rs7243091 (minor allele for both: G), the associations were independent. The odds ratio was 1.27 (95% CI: 1.04–1.53) for women with AG genotype for the SNP rs17759659 and 1.82 (95% CI: 1.21–2.73) for women with the GG genotype for the SNP rs7243091. No interaction between these two SNPs and established non-genetic risk factors of endometrial cancer was noticed.

Conclusion

Genetic polymorphisms in the BCL2 gene may be associated with the risk of endometrial cancer in Chinese women.

Caspase functions in cell death and disease

Caspases are a family of endoproteases that provide critical links in cell regulatory networks controlling inflammation and cell death. The activation of these enzymes is tightly controlled by their production as inactive zymogens that gain catalytic activity following signaling events promoting their aggregation into dimers or macromolecular complexes. Activation of apoptotic caspases results in inactivation or activation of substrates, and the generation of a cascade of signaling events permitting the controlled demolition of cellular components. Activation of inflammatory caspases results in the production of active proinflammatory cytokines and the promotion of innate immune responses to various internal and external insults. Dysregulation of caspases underlies human diseases including cancer and inflammatory disorders, and major efforts to design better therapies for these diseases seek to understand how these enzymes work and how they can be controlled.

Potentially functional polymorphisms in the CASP7 gene contribute to gastric adenocarcinoma susceptibility in an eastern Chinese population

BACKGROUND

Caspase 7 (CASP7) is an important regulator and executioner in the apoptosis pathway and plays a crucial role in cancer development and progression. However, few studies have evaluated associations between functional single nucleotide polymorphisms (SNPs) in the 3' untranslational region (UTR) of CASP7 and risk of gastric cancer.

METHODS

In a case-control study of 1117 patients with gastric cancer and 1146 cancer-free controls with frequency matching on age and sex, we genotyped four potentially functional SNPs (rs4353229T>C, rs10787498T>G, rs1127687G>A and rs12247479G>A) located in the microRNA binding sites of the CASP7 3' UTR by using Taqman assays and evaluated their associations with risk of gastric cancer by using logistic regression analyses as well as multifactorial dimension reduction (MDR) analysis.

RESULTS

In the single-locus analysis, only the CASP7 rs4353229 TT genotype was associated with 0.83-fold decreased risk (95% confidence interval [CI] = 0.70-0.98) of gastric cancer under a recessive model, compared with the CT/CC genotypes. In the combined analysis of all four SNPs, we found that the risk of gastric cancer decreased by 19% in those carrying any of the risk genotypes (adjusted odds ratio = 0.81, 95% CI = 0.68-0.96), compared with those carrying zero risk genotypes, and this risk was more evident in subgroups of younger age (<59 years), females, non-smokers, non-drinkers and patients with non-gastric cardia adenocarcinoma. Further MDR analysis suggested some evidence of interactions between the combined genotypes and other risk factors for gastric cancer.

CONCLUSIONS

Potentially functional CASP7 variants may contribute to risk of gastric cancer. Larger studies with different ethnic populations are warranted to validate our findings.

Association of CASP7 polymorphisms and survival of patients with non-small cell lung cancer with platinum-based chemotherapy treatment

BACKGROUND

CASP7 plays a crucial role in cancer development and chemotherapy efficacy. We, therefore, explored whether single nucleotide polymorphisms (SNPs) of the CASP7 gene can modulate outcomes of patients with advanced non-small cell lung cancer (NSCLC) treated with first-line platinum-based chemotherapy.

METHODS

We systematically genotyped 17 SNPs of CASP7 first in a discovery set of 279 patients with advanced NSCLC treated with platinum-based chemotherapy and then replicated the results in an independent set of 384 patients, in whom we evaluated associations with overall survival (OS) and progress-free survival (PFS) by Kaplan-Meier analysis and Cox hazards regression analysis.

RESULTS

In both discovery and validation sets as well as in the pooled analysis, heterozygotes of CASP7 rs2227310 and rs4353229 as well as rs12415607 variant allele were strongly associated with a better OS of NSCLC (in the pooled sample: adjusted hazard ratio [HR], 0.73; 95% CI = 0.59-0.90; P = .003; HR, 0.72; 95% CI = 0.59-0.89; P = .002; and HR, 0.76; 95% CI = 0.62-0.94; P = .009; respectively). In stratified analyses of the pooled data set, treated with paclitaxel, individuals carrying variant allele of rs2227310, rs4353229, and rs12415607 had significantly improved OS (HR, 0.60; 95% CI = 0.41-0.87; P = .008; HR, 0.58; 95% CI = 0.39-0.84; P = .004; and HR, 0.61; 95% CI = 0.42-0.89; P = .010; respectively).

CONCLUSIONS

This study provides evidence that genetic variations of CASP7 may modulate OS and PFS of patients with advanced NSCLC treated with platinum-based chemotherapy.

A functional variant at the miR-885-5p binding site of CASP3 confers risk of both index and second primary malignancies in patients with head and neck cancer

Caspases are important regulators and executioners in the apoptosis pathways and play crucial roles in carcinogenesis. We tested the hypothesis that functional variants of CASP genes are associated with risk of squamous cell carcinoma of the head and neck (SCCHN) and second primary malignancy (SPM). We genotyped 7 selected, potentially functional single nucleotide polymorphisms (SNPs) located in the microRNA binding sites of the 3' untranslational region (UTR; 2 in CASP3, 1 in CASP6, and 4 in CASP7) and evaluated their associations first with risk of SCCHN in 1066 patients with SCCHN and 1074 cancer-free control subjects and then with SPM in 846 patients in the same non-Hispanic white study population. We found that compared with the CASP3 TT genotype of rs1049253, the variant TC/CC genotypes were associated with significantly increased risk of SCCHN (adjusted odds ratio=1.29 and 95% confidence interval=1.07-1.56) and SPM (adjusted hazard ratio=1.79 and 95% CI=1.02-3.16) and worse SPM-free survival (log-rank P = 0.020), but no associations were found for the other 6 SNPs. We then performed additional experiments to seek functional relevance of the rs1049253 SNP. First, the luciferase activity and miR-885-5p mimic transfection tests suggested that CASP3 was the target of miR-885-5p and that rs1049253T>C resulted in altered regulation of the CASP3 expression. Second, the rs1049253 CC genotype was associated with reduced levels of CASP3 mRNA in peripheral blood mononuclear cells from 118 SCCHN patients and 103 cancer-free control subjects and lower levels of CASP3 protein expression in 11 head and neck cancer cell lines, compared with the TT genotype. Taken together, our data suggest that the miR-885-5p binding site rs1049253T>C SNP in the 3'-UTR of CASP3 modulates CASP3 expression at both mRNA and protein levels and thus contributes to SCCHN susceptibility.

Interactions between genetic polymorphisms in the apoptotic pathway and environmental factors on esophageal adenocarcinoma risk

How genetic variations in apoptosis pathway interact with environmental factors to contribute to esophageal adenocarcinoma (EA) risk has not been comprehensively investigated. We conducted a case-only analysis in 335 Caucasian EA patients that were genotyped for 242 single nucleotide polymorphisms (SNPs) in 43 apoptotic genes. Gene-environment interactions were assessed using a two-step approach. First, random forest algorithm was used to screen for the potential interacting markers. Next, we used case-only logistic regression model to estimate the effects of gene-environment interactions on EA risk. Four SNPs (PERP rs648802; PIK3CA rs4855094, rs7644468 and TNFRSF1A rs4149579) had significant interaction with gastroesophageal reflux disease (GERD). The presence of variant alleles in TP53BP1 rs560191, CASP7 rs7907519 or BCL2 rs12454712 enhanced the risk of smoking by 2.08-2.58 times [interaction odds ratio (ORi)=2.08-2.58, adjusted P-value (Padj)=0.02-0.04]. Compared with patients carrying ≤1 risk genotype, the risk of GERD on EA was increased in persons with two (ORi=1.89, Padj=0.016) or ≥3 (ORi=4.30, Padj<0.0001) risk genotypes. Compared with cases with ≤1 risk genotype, smoking-associated EA risk increased by 3.15 times when ≥2 risk genotypes were present (ORi=3.15, Padj<0.0001). In conclusion, interactions among apoptotic SNPs and GERD or smoking play an important role in EA development.

A Large-scale genetic association study of esophageal adenocarcinoma risk

The incidence of esophageal adenocarcinoma (EA) has been increasing rapidly, particularly among white males, over the past few decades in the USA. However, the etiology of EA and the striking male predominance is not fully explained by known risk factors. To identify susceptible genes for EA risk, we conducted a pathway-based candidate gene association study on 335 Caucasian EA cases and 319 Caucasian controls. A total of 1330 single-nucleotide polymorphisms (SNPs) selected from 354 genes were analyzed using an Illumina GoldenGate assay. The genotyped common SNPs include missense and exonic SNPs, SNPs within untranslated regions and 2 kb 5' of the gene, and tagSNPs for genes with little functional information available. Logistic regression adjusted for potential confounders was used to assess the genetic effect of each SNP on EA risk. We also tested gene-gender interactions using the likelihood ratio tests. We found that the genetic variants in the apoptosis pathway were significantly associated with EA risk after correcting for multiple comparisons. SNPs of rs3127075 in Caspase-7 (CASP7) and rs4661636 in Caspase-9 (CASP9) genes that play a critical role in apoptosis were found to be associated with an increased risk of EA. A protective effect of SNP rs572483 in the progesterone receptor (PGR) gene was observed among women carrying the variant G allele [adjusted odds ratio (OR) = 0.19; 95% confidence interval (CI) = 0.08-0.46] but was not observed among men (adjusted OR = 1.38; 95% CI = 0.95-2.00). In conclusion, this study suggests that the genetic variants of CASP7 and CASP9 in the apoptosis pathway may be important predictive markers for EA susceptibility and that PGR in the sex hormone signaling pathway may be associated with the gender differences in EA risk.

CASP8 polymorphisms contribute to cancer susceptibility: evidence from a meta-analysis of 23 publications with 55 individual studies

Several potentially functional polymorphisms of CASP8 encoding an apoptotic enzyme, caspase 8, have been implicated in cancer risk, but individually published studies showed inconclusive results. We performed a meta-analysis of 23 publications with a total of 55 174 cancer cases and 59 336 controls from 55 individual studies. We summarized the data on the associations between three studied CASP8 polymorphisms (G>C D302H, -652 6N del and Ex14-271A>T) and cancer risk and performed subgroup analysis by ethnicity, cancer type, study design and etiology. We found that D302H CC and CG variant genotypes were associated with significantly reduced overall risk of cancers using conservative random genetic models [homozygote comparison: odds ratios (OR) = 0.79; 95% confidence interval (CI): 0.69-0.92; dominant comparison: OR = 0.93, 95% CI: 0.89-0.98; recessive comparison: OR = 0.81, 95% CI: 0.71-0.93). In further stratified analyses, the reduced cancer risk remained for subgroups of Caucasians, breast or estrogen-related cancers, and hospital- or population-based studies, except for an elevated risk for brain tumors. Similarly, the -652 6N del polymorphism was also associated with significantly reduced overall risk of cancers (homozygote comparison: OR = 0.84, 95% CI: 0.75-0.94; dominant comparison: OR = 0.88, 95% CI: 0.81-0.96; recessive comparison: OR = 0.90, 95% CI: 0.82-0.99) and all subgroups analyzed. However, the Ex14-271A>T polymorphism did not appear to have an effect on cancer risk. These results suggest that CASP8 D302H and -652 6N del polymorphisms are potential biomarkers for cancer risk.