Study of PCDH10 gene expression in colorectal cancer
Date Issued
2008
Date
2008
Author(s)
Fu, Chao-Hua
Abstract
PCDH10 means protocadherin 10, a member of protocadherin family, which was a subgruop of cadherin superfamily. Protocadherin family members were predominantly expressed in the brain, and might play a role in neuron development or synapses connection. PCDH10 had two kinds of mRNA products, namely variant 1 and variant 2 respectively. PCDH10 variant 1 had been implied to be a tumor suppressor gene in multiple haematologic malignancies and nasopharyngeal carcinoma. However, there was no research about variant 2. o study if PCDH10 could be a tumor suppressor gene in colorectal carcinoma, the gene expression in peripheral blood mononuclear cells (PBMC), cell lines and colorectal cancer patients’ paired tissues were analyzed by RT-PCR. PCDH10 variant 1 mRNA was expressed in three of eight PBMC samples, and in HCT 116, HT 29 of the 12 colorectal cancer cell lines, and in MCF7, Hep3B, SK-Hep-1, PC-3, U-937 of the 8 other cancer cell lines. Human kidney embryonic cell HEK 293 and placenta tissues had expression, too. Except for high expression in MCF7 and HEK 293, the other cells had low gene expression level. In 23 paired colorectal patients’ tissues, PCDH10 variant 1 was more than 50% down regulated in 11 tumor tissues (47.83%) than the paired normal mucosa by semi-quantitative analysis.CDH10 variant 2 was expressed in MCF7, HEK 293 and placenta tissues but not PBMC or the other cell lines. PCDH10 variant 2 was only analyzed in six pairs of colorectal tissues and 1 paired pancreas cancer tissues. In the paired colorectal tissues, except for no expression in one paired tissue, PCDH10 variant 2 was expressed in four normal parts, and one tumor part. And in the paired pancreas cancer tissues, PCDH10 varaint 2 was expressed in tumor part. In addition, PCDH10 variant 2 was not expressed in 12 polyp tissues. CDH10 variant 1 was subsequent analyzed by real-time RT-PCR, and TATA box binding protein (TBP) as a internal control. PCDH10 variant 1 was down regulated in 15 of the 19 paired tissues (78.95%), and the tumor parts were more than 50% down regulated than the normal parts. In addition, in 1 pairs of benign tumors was significant down regulated, too. And 17 polyps were significant down regulated compared to normal mucosa tissues.orthern blot was performed and showed the existence of mRNA variants in MCF7 cell line. And then western blot was done to check protein expression in MCF7, HEK 293, placenta tissues and normal mucosa samples. HEK 293 transfected with PCDH10 variant 1 was a positive control. In northern blot, PCDH10 variant 2 from MCF7 had been proven existence. However, in western blot, except for the positive control, the protein existence had not been detected in other samples.he significant down regulation in gene expression assays of PCDH10 variant 1 suggests that PCDH10 variant 1 is a tumor suppressor gene of colorectal cancer. PCDH10 variant 2 trends to be detected in samples that have high expression of PCDH10 variant 1, so PCDH10 variant 2 may be a byproduct which results from transcription error. However, PCDH10 variant 2 also can be detected in the tumor part of one pair of colorectal tissues and the paired pancreas cancer tissues that have low PCDH10 variant 1 expression, so the regulation of the expression of PCDH10 variant 2 may involve other mechanisms.
Subjects
colorectal cancer
chromosome 4
tumor suppressor gene
gene expression assay
SDGs
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