Alteration of tumor suppressor BMP5 in sporadic colorectal cancer: a genomic and transcriptomic profiling based study

Sporadic colorectal cancer (CRC) develops through distinct molecular events. Loss of 18q chromosome is a conspicuous event in the progression of adenoma to carcinoma. There is limited information regarding the molecular effectors of this event. Earlier, we had reported ATP8B1 as a novel gene associated with CRC. ATP8B1 belongs to the family of P-type ATPases (P4 ATPase) that primarily function to facilitate the translocation of phospholipids. In this study, we attempt to implicate ATP8B1 gene located on chromosome 18q as a tumor suppressor gene. We studied indigenous patient data and confirmed the reduced expression of ATP8B1 in tumor samples. CRC cell lines were engineered with reduced and enhanced levels of ATP8B1 which provided a tool to study its role on cancer progression. Forced reduction of ATP8B1 expression either by CRISPR/Cas9 or shRNA was associated with increased growth and proliferation of CRC cell line - HT29. In contrast, overexpression of ATP8B1 resulted in reduced growth and proliferation of SW480 cell line. We generated a network of genes that are downstream of ATP8B1. Further, we provide predicted effect of modulation of ATP8B1 levels on this network and possible effect on fatty acid metabolism related genes. These results provide evidence in support of ATP8B1 being a tumor suppressor that may affect fatty acid metabolism in CRC.

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Microsatellite Instability and Loss of Heterozygosity of Tumor Suppressor Genes in Bosnian Patients with Sporadic Colorectal Cancer

Bosnian Journal of Basic Medical Sciences ◽

10.17305/bjbms.2008.2883 ◽

2008 ◽

Vol 8 (4) ◽

pp. 313-321

Author(s):

Vesna Hadžiavdić ◽

Nada Pavlović-Čalić ◽

Izet Eminović

Keyword(s):

Colorectal Cancer ◽

Tumor Suppressor ◽

Microsatellite Instability ◽

Tumor Suppressor Genes ◽

Genetic Alterations ◽

Sporadic Colorectal Cancer ◽

Tumor Type ◽

Suppressor Genes ◽

Amsterdam Criteria ◽

Surrounding Healthy Tissue

Considering its frequency, high mortality rate as well as many etiological mysteries colorectal cancer is a challenge to contemporary science. In our study we analyzed RER + and RER - phenotypes and their relations with clinical-pathological characteristics of sporadic colorectal cancers. We also analyzed genetic alterations of tumor suppressor genes as well as their relation with microsatellite instability. The study was based on 54 tumor samples and 54 samples of the surrounding healthy tissue of patients with colorectal cancer. According to Amsterdam Criteria and Bethesda Criteria 35/54 or 64,81% belonged in the group of sporadic colorectal cancer. Mononucleotide marker Bat 25 showed instability in 48,57%; Bat 26 in 45,71% and Bat 40 in 29/35 82,86% of tumor samples. Considering dinucleotide markers, TP 53 showed instability in 54,29% and DS123 in 37,14% of tumor samples. Genetic alterations in tumor suppressor genes were found in tumor tissue: NM 23 in 54,29% samples, p53 in 51,43%, APC in 51,43%, DCC2 in 34,29%, RB1 in 22, 86% and DCC 1 in 28,57%. Our studies confirmed that genetic instability had an important role in the development of tumor type. Our results showed that mononucleotide marker Bat 40 might be used for an easy and fast screening procedure in Bosnian population, because it exhibited high percent of microsatellite instability and was in relation with RER+ phenotype. This investigation showed that different genetic alterations may occur during cancer development in each individual patient’s tumor. These changes result in MMR inactivation, which causes RER+ phenotype. Our results suggest a connection between alteration in some tumor suppressor genes and MSI phenotype of sporadic colorectal cancer in Bosnian population.

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