Identification of a protective haplogenotype within CAPN10 gene influencing colorectal cancer susceptibility

Changes in calpain-2 expression during glioblastoma progression predisposes tumor cells to temozolomide resistance by minimizing DNA damage and p53-dependent apoptosis

BACKGROUND

Glioblastoma multiforme (GBM) is characterized by an unfavorable prognosis for patients affected. During standard-of-care chemotherapy using temozolomide (TMZ), tumors acquire resistance thereby causing tumor recurrence. Thus, deciphering essential molecular pathways causing TMZ resistance are of high therapeutic relevance.

METHODS

Mass spectrometry based proteomics were used to study the GBM proteome. Immunohistochemistry staining of human GBM tissue for either calpain-1 or -2 was performed to locate expression of proteases. In vitro cell based assays were used to measure cell viability and survival of primary patient-derived GBM cells and established GBM cell lines after TMZ ± calpain inhibitor administration. shRNA expression knockdowns of either calpain-1 or calpain-2 were generated to study TMZ sensitivity of the specific subunits. The Comet assay and ɣH2AX signal measurements were performed in order to assess the DNA damage amount and recognition. Finally, quantitative real-time PCR of target proteins was applied to differentiate between transcriptional and post-translational regulation.

RESULTS

Calcium-dependent calpain proteases, in particular calpain-2, are more abundant in glioblastoma compared to normal brain and increased in patient-matched initial and recurrent glioblastomas. On the cellular level, pharmacological calpain inhibition increased the sensitivities of primary glioblastoma cells towards TMZ. A genetic knockdown of calpain-2 in U251 cells led to increased caspase-3 cleavage and sensitivity to neocarzinostatin, which rapidly induces DNA strand breakage. We hypothesize that calpain-2 causes desensitization of tumor cells against TMZ by preventing strong DNA damage and subsequent apoptosis via post-translational TP53 inhibition. Indeed, proteomic comparison of U251 control vs. U251 calpain-2 knockdown cells highlights perturbed levels of numerous proteins involved in DNA damage response and downstream pathways affecting TP53 and NF-κB signaling. TP53 showed increased protein abundance, but no transcriptional regulation.

CONCLUSION

TMZ-induced cell death in the presence of calpain-2 expression appears to favor DNA repair and promote cell survival. We conclude from our experiments that calpain-2 expression represents a proteomic mode that is associated with higher resistance via "priming" GBM cells to TMZ chemotherapy. Thus, calpain-2 could serve as a prognostic factor for GBM outcome.

Heterorhabditis and Photorhabdus Symbiosis: A Natural Mine of Bioactive Compounds

Phylum Nematoda is of great economic importance. It has been a focused area for various research activities in distinct domains across the globe. Among nematodes, there is a group called entomopathogenic nematodes, which has two families that live in symbiotic association with bacteria of genus Xenorhabdus and Photorhabdus, respectively. With the passing years, researchers have isolated a wide array of bioactive compounds from these symbiotically associated nematodes. In this article, we are encapsulating bioactive compounds isolated from members of the family Heterorhabditidae inhabiting Photorhabdus in its gut. Isolated bioactive compounds have shown a wide range of biological activity against deadly pathogens to both plants as well as animals. Some compounds exhibit lethal effects against fungi, bacteria, protozoan, insects, cancerous cell lines, neuroinflammation, etc., with great potency. The main aim of this article is to collect and analyze the importance of nematode and its associated bacteria, isolated secondary metabolites, and their biomedical potential, which can serve as potential leads for further drug discovery.

Calpain-calpastatin system and cancer progression

The calpain system is required by many important physiological processes, including the cell cycle, cytoskeleton remodelling, cellular proliferation, migration, cancer cell invasion, metastasis, survival, autophagy, apoptosis and signalling, as well as the pathogenesis of a wide range of disorders, in which it may function to promote tumorigenesis. Calpains are intracellular conserved calcium-activated neutral cysteine proteinases that are involved in mediating cancer progression via catalysing and regulating the proteolysis of their specific substrates, which are important signalling molecules during cancer progression. μ-calpain, m-calpain, and their specific inhibitor calpastatin are the three molecules originally identified as comprising the calpain system and they contain several crucial domains, specific motifs, and functional sites. A large amount of data supports the roles of the calpain-calpastatin system in cancer progression via regulation of cellular adhesion, proliferation, invasion, metastasis, and cellular survival and death, as well as inflammation and angiogenesis during tumorigenesis, implying that the inhibition of calpain activity may be a potential anti-cancer intervention strategy targeting cancer cell survival, invasion and chemotherapy resistance.

GAS2-Calpain2 axis contributes to the growth of leukemic cells

Growth arrest specific 2 (GAS2) modulates cell cycle, apoptosis, and Calpain activity. GAS2-Calpain2 axis is required for the growth of BCR-ABL(+) hematopoietic cells and chronic myeloid leukemia cells. However, the expression of GAS2 in acute leukemia patients remains unclear and what role GAS2-Calpain2 axis plays in these leukemic cells is not known yet. In this study, GAS2 was found to have significantly higher expression in 16 various leukemic cell lines than in control cells. Using THP-1 cells (from acute myeloid leukemia patient, AML) and Jurkat cells (from acute lymphoid leukemia patient, ALL) as models, we found that GAS2 silence led to elevated Calpain activity, decreased cellular growth, and inhibition of colony-forming cell (CFC) production; and these effects could be rescued by GAS2 re-expression. Moreover, GAS2 silence prevented tumor formation of THP-1 cells in nude mice. In both THP-1 and Jurkat cells, GAS2 interacted with Calpain2 rather than Calpain1. The dominant negative form of GAS2 (GAS2DN, GAS2Δ171-313) had similar effects on leukemic cells through the activation of Calpain. Importantly, Calpain2 silence abolished the proliferation inhibition induced by GAS2 targeting. We also found that GAS2 was aberrantly expressed and Calpain activity was decreased in clinical isolates from acute leukemia patients. Taken together, our results demonstrated the deregulation of GAS2 in both AML and ALL and the requirement of GAS2-Calpain2 axis for the growth of leukemic cells, which will help to understand the molecular pathogenesis of hematological malignancies and possibly to develop novel approaches to treat these deadly diseases.

Calpain-10 SNP43 and SNP19 polymorphisms and colorectal cancer: a matched case-control study

OBJECTIVE

Insulin resistance (IR) is an established risk factor for colorectal cancer (CRC). Given that CRC and IR physiologically overlap and the calpain-10 gene (CAPN10) is a candidate for IR, we explored the association between CAPN10 and CRC risk.

METHODS

Blood samples of 400 case-control pairs were genotyped, and the lifestyle and dietary habits of these pairs were recorded and collected. Unconditional logistic regression (LR) was used to assess the effects of CAPN10 SNP43 and SNP19, and environmental factors. Both generalized multifactor dimensionality reduction (GMDR) and the classification and regression tree (CART) were used to test gene-environment interactions for CRC risk.

RESULTS

The GA+AA genotype of SNP43 and the Del/Ins+Ins/Ins genotype of SNP19 were marginally related to CRC risk (GA+AA: OR = 1.35, 95% CI = 0.92-1.99; Del/Ins+Ins/ Ins: OR = 1.31, 95% CI = 0.84-2.04). Notably, a high-order interaction was consistently identified by GMDR and CART analyses. In GMDR, the four-factor interaction model of SNP43, SNP19, red meat consumption, and smoked meat consumption was the best model, with a maximum cross-validation consistency of 10/10 and testing balance accuracy of 0.61 (P < 0.01). In LR, subjects with high red and smoked meat consumption and two risk genotypes had a 6.17-fold CRC risk (95% CI = 2.44-15.6) relative to that of subjects with low red and smoked meat consumption and null risk genotypes. In CART, individuals with high smoked and red meat consumption, SNP19 Del/Ins+Ins/Ins, and SNP43 GA+AA had higher CRC risk (OR = 4.56, 95%CI = 1.94-10.75) than those with low smoked and red meat consumption.

CONCLUSIONS

Though the single loci of CAPN10 SNP43 and SNP19 are not enough to significantly increase the CRC susceptibility, the combination of SNP43, SNP19, red meat consumption, and smoked meat consumption is associated with elevated risk.

Oncogene GAEC1 regulates CAPN10 expression which predicts survival in esophageal squamous cell carcinoma

AIM: To identify the downstream regulated genes of GAEC1 oncogene in esophageal squamous cell carcinoma and their clinicopathological significance.

METHODS: The anti-proliferative effect of knocking down the expression of GAEC1 oncogene was studied by using the RNA interference (RNAi) approach through transfecting the GAEC1-overexpressed esophageal carcinoma cell line KYSE150 with the pSilencer vector cloned with a GAEC1-targeted sequence, followed by MTS cell proliferation assay and cell cycle analysis using flow cytometry. RNA was then extracted from the parental, pSilencer-GAEC1-targeted sequence transfected and pSilencer negative control vector transfected KYSE150 cells for further analysis of different patterns in gene expression. Genes differentially expressed with suppressed GAEC1 expression were then determined using Human Genome U133 Plus 2.0 cDNA microarray analysis by comparing with the parental cells and normalized with the pSilencer negative control vector transfected cells. The most prominently regulated genes were then studied by immunohistochemical staining using tissue microarrays to determine their clinicopathological correlations in esophageal squamous cell carcinoma by statistical analyses.

RESULTS: The RNAi approach of knocking down gene expression showed the effective suppression of GAEC1 expression in esophageal squamous cell carcinoma cell line KYSE150 that resulted in the inhibition of cell proliferation and increase of apoptotic population. cDNA microarray analysis for identifying differentially expressed genes detected the greatest levels of downregulation of calpain 10 (CAPN10) and upregulation of trinucleotide repeat containing 6C (TNRC6C) transcripts when GAEC1 expression was suppressed. At the tissue level, the high level expression of calpain 10 protein was significantly associated with longer patient survival (month) of esophageal squamous cell carcinoma compared to the patients with low level of calpain 10 expression (37.73 ± 16.33 vs 12.62 ± 12.44, P = 0.032). No significant correction was observed among the TNRC6C protein expression level and the clinocopathologcial features of esophageal squamous cell carcinoma.

CONCLUSION: GAEC1 regulates the expression of CAPN10 and TNRC6C downstream. Calpain 10 expression is a potential prognostic marker in patients with esophageal squamous cell carcinoma.

The calpain/calpastatin system has opposing roles in growth and metastatic dissemination of melanoma

Conventional calpains are ubiquitous cysteine proteases whose activity is promoted by calcium signaling and specifically limited by calpastatin. Calpain expression has been shown to be increased in human malignant cells, but the contribution of the calpain/calpastatin system in tumorigenesis remains unclear. It may play an important role in tumor cells themselves (cell growth, migration, and a contrario cell death) and/or in tumor niche (tissue infiltration by immune cells, neo-angiogenesis). In this study, we have used a mouse model of melanoma as a tool to gain further understanding of the role of calpains in tumor progression. To determine the respective importance of each target, we overexpressed calpastatin in tumor and/or host in isolation. Our data demonstrate that calpain inhibition in both tumor and host blunts tumor growth, while paradoxically increasing metastatic dissemination to regional lymph nodes. Specifically, calpain inhibition in melanoma cells limits tumor growth in vitro and in vivo but increases dissemination by amplifying cell resistance to apoptosis and accelerating migration process. Meanwhile, calpain inhibition restricted to host cells blunts tumor infiltration by immune cells and angiogenesis required for antitumor immunity, allowing tumor cells to escape tumor niche and disseminate. The development of highly specific calpain inhibitors with potential medical applications in cancer should take into account the opposing roles of the calpain/calpastatin system in initial tumor growth and subsequent metastatic dissemination.

Calpain 10 gene and laryngeal cancer: a survival analysis

BACKGROUND

Laryngeal carcinoma is a common upper respiratory tract cancer with different environmental and genetic factors involved in its development. Calpains are Ca2+-dependent cysteine proteases that modulate cellular function. A novel association between calpain 10 (CAPN10) haplotypes and laryngeal cancer has been found recently. Therefore, the goal of this study was to analyze the contribution of CAPN10 alleles to laryngeal cancer survival.

METHODS

Patients were recruited from southern Spain. Genotypes were determined using pyrosequencing technology. We analyzed CAPN10 UCSNP-44, UCSNP-43, UCSNP-19, and UCSNP-63 allelic distributions in 199 patients with unrelated laryngeal cancer. Survival curves were calculated from the date of the intervention to the date of death. Multivariate analyses were done using the Cox proportional risk model.

RESULTS

UCSNP-19, UCSNP-43, and UCSNP-44 were unrelated to survival in both univariate and multivariate analyses. However, for UCSNP-63 genotype 12 a significant relationship was observed in multivariate analysis (hazard ratio [HR] = 2.73; 95% confidence interval [CI], 1.21-6.20).

CONCLUSION

CAPN10 UCSNP-63 genotype 12 seems to be related with a worse prognosis in laryngeal cancer.

The calpain system and cancer

The calpains are a conserved family of cysteine proteinases that catalyse the controlled proteolysis of many specific substrates. Calpain activity is implicated in several fundamental physiological processes, including cytoskeletal remodelling, cellular signalling, apoptosis and cell survival. Calpain expression is altered during tumorigenesis, and the proteolysis of numerous substrates, such as inhibitors of nuclear factor-κB (IκB), focal adhesion proteins (including, focal adhesion kinase and talin) and proto-oncogenes (for example, MYC), has been implicated in tumour pathogenesis. Recent evidence indicates that the increased expression of certain family members might influence the response to cancer therapies, providing justification for the development of novel calpain inhibitors.

Genetics of childhood-onset inflammatory bowel disease

Nearly a third of inflammatory bowel disease (IBD) patients present in childhood or adolescence, with epidemiological and natural history studies clearly demonstrating a rising incidence in this population. Although early-onset disease has a distinct phenotype, such as more extensive disease at onset and rapid progression, two recent genome-wide association studies (GWAS) carried out exclusively in this age group have demonstrated marked genetic similarities to adult disease. Although these parallels exist, this review will focus on the novel regions associated with early-onset IBD susceptibility identified by these early-onset GWAS. These new loci reaffirm the dysregulated pathways previously implicated in adult IBD pathogenesis and provide further insight into the pathophysiology of intestinal inflammation. The newly identified loci and expression data suggest mutations in genes encoding IL-27, which is involved in Th17 effector cell physiology; MTMR3, which we demonstrate is an essential component of autophagy; and CAPN10, which is necessary in regulating endoplasmic reticulum stress. In addition, the roles of PSMG1, TNFRSF6B, ZMIZ1 and SMAD3 are also discussed in relation to abnormal protein degradation and the secondary immune response. It is clear that with increasing technology our understanding of IBD pathogenesis is deepening at the genomic level and that the use of early patient selection coupled with ongoing work on therapeutic targets will lead to improved disease-modifying treatments in the near future.

TGFB1 509 C/T polymorphism and colorectal cancer risk: a meta-analysis

Transforming growth factor β (TGF-β) is a cytokine. The TGF-β signaling pathway plays an important role in controlling cell proliferation and differentiation involved in colorectal carcinogenesis. In mammalian cells, TGFB1 is the most abundant subtype of TGF-β. The 509 C/T polymorphism in TGFB1 has been implicated in colorectal cancer risk. However, published data remain conflicting. To derive a more precise estimation of the relationship, a meta-analysis of 994 cases and 2,335 controls from five published case-control studies was performed. Overall, significantly increased colorectal cancer risks were found for CC versus TT (OR=1.62; 95% CI: 1.30-2.02; Pheterogeneity=0.118), TC+CC versus TT (OR=1.30; 95% CI: 1.08-1.58; Pheterogeneity=0.259) and CC versus TC+TT (OR=1.48; 95% CI: 1.26-1.75; Pheterogeneity=0.244). In the subgroup analysis by ethnicity, significantly increased risks were also found among Asians for CC versus TT (OR=1.77; 95% CI: 1.40-2.24; Pheterogeneity=0.519), TC+CC versus TT (OR=1.38; 95% CI: 1.13-1.68; Pheterogeneity=0.679) and CC versus TC+TT (OR=1.58; 95% CI: 1.31-1.89; Pheterogeneity=0.340). However, no significant associations were found among Europeans for all genetic models. This meta-analysis showed that TGFB1 509 C allele is a risk factor for developing colorectal cancer in Asians.