CD38 gene polymorphism rs1130169 contribution to the increased gene expression and risk of colorectal cancer (pilot study)

BACKGROUND

Genetic variations in immune signaling genes may have regulatory effect on phenotypic heterogeneity of immune cells and immune functions, hence promoting tumor growth.

PURPOSE

We compared the frequencies of potentially functional CD38 gene single nucleotide polymorphisms rs1130169 (T > C) in 86 healthy controls and 90 colorectal cancer (CRC) cases to assess their association with cancer risk and CD38 gene expression.

RESULTS

The association between allele C rs1130169 and CRC risk was observed. Allele C was also significantly correlated with an increased CD38 mRNA level and CD38 positive cell percentages in peripheral blood of healthy controls that could be a possible explanation for CRC risk in C allele carriers. In peripheral blood of CRC patients CD38 mRNA and serum soluble CD38 protein levels significantly differed from those in healthy controls. Calculation of the CD38 full-length and with the third exon deletion mRNA ratio in corresponding samples showed that the mRNA isoform ratio was significantly higher in CRC cases than in controls. It suggests that alternative splicing regulates elevation of CD38 full-length mRNA level in peripheral blood of CRC patients. We also have observed higher expression levels of CD38 full-length mRNA in peripheral blood of CRC patients with lymph node metastases compared to patients without metastases.

CONCLUSION

This study indicated biological significance of rs1130169 variations that can alter differences in CRC risk by regulating CD38 gene expression.

[The correlation of expression of MUC1, ICAM1, IL32, FcyR3A and FoxP3 in tumor niduses of patients with breast cancer]

The hypo-glycated mucin I (MUC I) frequently is redundantly expressed in cells of breast carcinoma that is considered as an unfavorable prognostic marker for patients with breast cancer. The purpose of study is to evaluate in tumor areas of patients with breast cancer the interrelationships between expression of MUC I and genes participating in implementation of immune reactions. The technique of polymerase chain reaction with reverse transcription in real-time was applied to investigate expression of genes of MUC I, Fas, ICAMI, FcyR3A, FcyR3B, FoxP3, IL2Ra, IL32 and TNF in tumor areas of 40 patients with breast cancer. The level of mRNA of each of analyzed genes was evaluated relatively to three genes of household. The rate of detection of mRNA MUC I amounted to 80%, mRNA Fas - 95%, mRNA ICAM I - 97.5%, mRNA FcyR3A - 95%, mRNA FcyR3B - 32.5%, mRNA FoxP3 - 85%, mRNA IL2Ra - 87.5%, mRNA IL32 - 75%, mRNA TNF - 95%. The direct correlation was established between levels of mRNA MUC I, ICAM I, IL32, FcyR3A and FoxP3. The most strong relationship was registered between levels of expression of genes MUC I and IL32 (r-0.72; p=0.0001). In comparison with MUC I negative breast carcinoma, MUC I positive breast carcinoma characterized by higher level of mRNA of pro-inflammatory cytokines IL32 and ЕТА, molecules of adhesion ICAM I and molecular marker of T-regulative cells FoxP3. The given profile of expression of genes in tumors of patients with breast cancer demonstrates relationship of expression of MUC I with inflammation and its modulation by T-regulative cells. The effect of expression of analyzed genes on phenotype of cancer cells and course of disease are discussed.

[DR3/LARD mRNA spliced variants' frequency at colorectal cancer]

There are a lot of "death receptor" DR3/LARD mRNA variants that are formed during the alternative splicing. Membrane and soluble forms of the receptor are encoded with various types of the DR3/LARD mRNA and perform different functions. Using RT-PCR, the DR3/LARD mRNA spliced variants' frequency was measured in colon cancer patients' samples and cancer cell lines. In samples under investigation, four forms of the DR3/LARD mRNA were found with various frequencies. Two of them encoded the membrane receptors (LARD la mRNA and DR3beta mRNA) and other two expressed the soluble molecules (LARD 3 mRNA and soluble DR3beta mRNA). In blood of healthy volunteers 11 combinations (spectrums) of the DR3/LARD mRNA forms were revealed, and the "full" spectrum including all four variants of DR3/LARD mRNA dominated. In blood of colon cancer patients and tumour tissue samples, 6 DR3/LARD mRNA spectrums were found. The diversity of the DR3/LARD mRNA spectrums was decreased in colon cancer patients because of the frequency reduction of soluble DR3beta mRNA. Reduction of a variety of spectrums in cells of the patients was caused by decrease in occurrence of mRNA of the soluble DR3beta form. In samples of the tumor centers the spectrum with absence only mRNA of the soluble DR3beta form dominated. In blood of patients two spectrums prevailed: "full" range and presented mRNA LARD la and mRNA LARD 3. Only these two spectrums of mRNA DR3/LARD were also found in the tumor cell lines. Distinctions in occurrence of spectrums of DR3/LARD mRNA at healthy volunteers and colon cancer patients can define a different susceptibility of immunocompetent and tumor cells for apoptosis signals.

[Heterogeneous expression of CD38 gene in tumor tissue in patients with colorectal cancer]

The CD38 gene codes a membrane protein which takes part in cell adhesion and catalyzes the formation of cyclic ADP-ribose. Using RT-PCR method we tested the presence of full-size and alternative forms of mRNA CD38 in samples of tumor tissue of patients with colorectal cancer and in tumor cell lines. It was shown that there are the cells in the tumor tissue which expressed CD38 gene. In tumor tissue of patients the alternative form of mRNA CD38 was detected less frequently than full-size form. Cells of lines Colo-205, T-84, HCT15 and HCT116 contained mRNA CD38, in cells of lines Caco-2 and SW-620 mRNA CD38 was absent. In cells of tumor tissue on the first stage of colorectal cancer CD38 gene was expressed in 100% of cases. On the second, third and fourth stages of the disease gene expression was observed less often. The frequency of mRNA CD38 detection not depend on tumor localization, tumor grade and presence of metastases. Using method of restriction analysis CpG methylation was detected in binding sites of transcription factor Sp1 and receptor of retinoic acid (RARE) in all tested samples of tumor tissue independently of the presence or absence of mRNA CD38. The obtained data suggest that in the tumor cells of patients with colorectal cancer the expression of the CD38 gene is heterogeneous.