Mutational analysis of caspase-14 gene in common carcinomas

Expression of caspase 14 and filaggrin in oral squamous carcinoma

Caspase 14 is one of the latter discovered members of the caspase enzyme family and, although sharing sequence homologies with the other caspases, it is not involved in apoptosis. Together with its co-factor filaggrin, it plays an important role in skin barrier formation. It is already known that caspase 14 proteins are reduced during neoplastic dedifferentiation in cervical intraepithelial neoplasms and in invasive cervical carcinomas. Oral squamous carcinoma tissues have not been systematically evaluated for caspase 14 expression yet. Formalin-fixed and paraffin-embedded samples from oral squamous carcinomas (n = 36 tumours from 34 patients), metastases (n = 15) and controls (leukoplakia, n = 10) were analysed by immunohistochemistry. In carcinomas, human papilloma virus (HPV) infection was tested by PCR. Here we demonstrate that, in oral epithelia, caspase 14 is expressed mainly by cells of the intermediate and superficial cell layers while filaggrin is expressed only in keratinising foci in leukoplakia. Caspase 14 and filaggrin are co-localised. In invasive oral carcinomas, reduced expression of caspase 14 was detectable in 47 % of tumours but was not associated with keratinisation, tumour differentiation or HPV infection. Filaggrin was detectable in a subfraction of tumours (56 %) and was restricted to keratinising areas of the carcinomas. In summary, in contrast to cervical carcinomas, partial loss of caspase 14 is not associated with dedifferentiation in neoplastic lesions of the oral mucosa or HPV infection.

Mutational analysis of CASP10 gene in colon, breast, lung and hepatocellular carcinomas

AIMS

Evasion of apoptosis is a feature of cancer cells. As a mechanism of apoptosis inactivation in cancer cells, somatic mutations of pro-apoptotic genes have been reported in many cancers. Caspase-10 is an initiation-phase caspase, and somatic mutation of CASP10 that encodes caspase-10 has been found in non-Hodgkin's lymphoma and gastric carcinoma.

METHODS

The aim of this study was to explore whether CASP10 gene is somatically mutated in colon, breast, lung, and hepatocellular carcinomas. We analysed the entire coding region and all splice sites of CASP10 in 47 colon, 47 breast, 47 lung, and 47 hepatocellular carcinomas by a single-strand conformation polymorphism (SSCP) assay.

RESULTS

We found two CASP10 mutations in the colon cancers (2/47; 4.3%), but none in breast, lung or hepatocellular carcinomas. One mutation [c.41A > C (p.Lys14Thr)] was a missense mutation, while the other was a substitution mutation in a splice site (c.684 + 4G > A). The colon cancer with the CASP10 missense mutation harboured additional CASP gene mutations (CASP3, 7 and 8).

CONCLUSION

Our data indicate that somatic mutation of CASP10 is rare in colon, breast, lung, and hepatocellular carcinomas. However, the data also suggest that CASP10 mutation might contribute to the pathogenesis of some colon carcinomas together with other CASP gene mutations.

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

Caspase-3, caspase-7, and caspase-8 are important caspases in the apoptosis pathway and play an important role in the development and progression of cancer. We examined the association between genetic variants in the caspase-3, caspase-7, and caspase-8 genes and risk for endometrial cancer among Chinese women. Genotypes for 1,028 women with endometrial cancer and 1,003 healthy controls were determined with the Affymetrix MegAllele Targeted Genotyping System and Molecular Inversion Probe method. Of 35 selected single-nucleotide polymorphisms, four in the caspase-7 gene were in high linkage disequilibrium (rs11593766, rs3124740, rs11196445, and rs11196418) and associated with the risk for endometrial cancer. The AA genotype of rs11196418 [odds ratio, 0.36; 95% confidence interval (95% CI), 0.14-0.94] and the G allele of rs11593766 were associated with reduced risk (odds ratio of 0.75 and 95% CI of 0.59-0.96 for carriers of one G allele; odds ratio of 0.70 and 95% CI of 0.24-2.03 for carriers of two G alleles). The AA genotype of rs11196445 (odds ratio, 1.74; 95% CI, 0.99-3.05), the CC genotype of rs3124740 (odds ratio, 1.36; 95% CI, 1.06-1.75), and the GG genotype of rs10787498 in the caspase-7 gene (odds ratio, 1.90; 95% CI, 1.16-3.11) were associated with increased risk compared with homozygotes of the major alleles. The gene-disease association seemed to be more pronounced among premenopausal women, although tests for multiplicative interaction between genes and menopausal status failed to reach statistical significance. The GG genotype of rs2705901 in the caspase-3 gene was significantly associated with increased cancer risk compared with the CC genotype (odds ratio, 2.25; 95% CI, 1.03-4.95). No association was observed between polymorphisms of the caspase-8 gene and risk for endometrial cancer. These findings suggest that genetic variants in caspase-3 and caspase-7 may play a role in endometrial cancer susceptibility.

Mutational analysis of CASP1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and 14 genes in gastrointestinal stromal tumors

Deregulation of apoptosis is one of the hallmarks of cancer, and inactivation of cancer cell apoptosis has been reported in many cancers. Caspases, the main executioners during apoptosis and inflammation, have been reported to harbor inactivating mutations in several cancers. The aim of this study was to explore whether CASP1 to 10 and 14 genes that encode caspase 1 to 10 and 14 are somatically mutated in gastrointestinal stromal tumor. We analyzed the entire coding region and all splice sites of all 11 human CASP genes for the detection of somatic mutations in 22 gastrointestinal stromal tumors by a single strand conformation polymorphism assay. We found a recurrent CASP4 mutation (c.1093C>G [p.L365V]) in 4 gastrointestinal stromal tumors, but there were no mutations in the other 10 CASPs. The CASP4 mutation was a missense mutation and was predicted to substitute amino acids in the small protease subunit of caspase 4. Overall, the gastrointestinal stromal tumor tissues harbored a CASP mutation in 18.2% (4/22). Our data indicate that somatic mutation of the CASP4 gene is common in gastrointestinal stromal tumor and suggest a possibility that CASP4 mutation might lead to alteration of apoptotic or inflammatory function and contribute to the pathogenesis of some gastrointestinal stromal tumors.

Caspase-14 reveals its secrets

Caspase-14 is a unique member of the evolutionarily conserved family of cysteinyl aspartate-specific proteinases, which are mainly involved in inflammation and apoptosis. However, recent evidence also implicates these proteases in proliferation and differentiation. Although most caspases are ubiquitously expressed, caspase-14 expression is confined mainly to cornifying epithelia, such as the skin. Moreover, caspase-14 activation correlates with cornification, indicating that it plays a role in terminal keratinocyte differentiation. The determination of in vitro conditions for caspase-14 activity paved the way to identifying its substrates. The recent development of caspase-14-deficient mice underscored its importance in the correct degradation of (pro)filaggrin and in the formation of the epidermal barrier that protects against dehydration and UVB radiation. Here, we review the current knowledge on caspase-14 in skin homeostasis and disease.