SIRT1 promotes the progression and chemoresistance of colorectal cancer through the p53/miR-101/KPNA3 axis.

INTRODUCTION: Sirtuin 1 (SIRT1) is a key modulator in several types of cancer, including colorectal cancer (CRC). Here, we probed into the molecular mechanism of SIRT1 regulating the development and chemoresistance of CRC. METHODS: Differentially expressed genes related to the growth, metastasis and chemoresistance of CRC were identified by bioinformatics analysis. The expression of SIRT1 in clinical tissues from CRC patients and CRC cell lines was detected by RT-qPCR. Interactions among SIRT1, p53, miR-101 and KPNA3 were analyzed. The effect of SIRT1 on the cell viability, migration, invasion, epithelial-mesenchymal transformation and chemoresistance to 5-FU was evaluated using loss-function investigations in CRC cells. Finally, a xenograft model of CRC and a metastasis model were constructed for further exploration of the roles of SIRT1 in vivo. RESULTS: SIRT1 was elevated in CRC tissues and cell lines. SIRT1 decreased p53 via deacetylation, and consequently downregulated the expression of miR-101 while increasing that of the miR-101 target gene KPNA3. By this mechanism, SIRT1 enhanced the proliferation, migration, invasion, epithelial-mesenchymal transformation, and resistance to 5-FU of CRC cells. In addition, in vivo data also showed that SIRT1 promoted the growth, metastasis and chemoresistance to 5-FU of CRC cells via regulation of the p53/miR-101/KPNA3 axis. CONCLUSIONS: In conclusion, SIRT1 can function as an oncogene in CRC by accelerating the growth, metastasis and chemoresistance to 5-FU of CRC cells through the p53/miR-101/KPNA3 axis.

[Study on polymorphisms of CYP3A5 gene and their clinical role].

OBJECTIVE: To investigate the polymorphisms of CYP3A5 gene in Chinese population and the association between CYP3A5 genotypes and their clinical functions. METHODS: CYP3A5 gene varisances were detected in 180 samples using denaturing high-performance liquid chromatography(DHPLC), and CsA concentrations in 12 of 180 samples from hemopoietic stem cell transplant recipients were monitored by a commercial fluorescence polarization immunoassay. The data were analyzed by a statistical software. RESULTS: In the 180 samples, there was only one allelic variant CYP3A5*3 with a frequency of 76.1% (274/360), and there were three CYP3A5 genotypes, namely CYP3A5*1/*1, CYP3A5*1/*3 and CYP3A5*3/*3 with frequencies of 5.6%, 36.7% and 57.8% respectively. Also, there were significant differences in CsA concentrations, including standardized trough concentrations C(0) and two-hour peak concentrations C(2), between CYP3A5 CYP3A5*1/*1 and CYP3A5*1/*3 found in 12 hemopoietic stem cell transplant recipients, and both C(0) and C(2) in CYP3A5*1/*1 were lower than those in CYP3A5*1/*3. CONCLUSION: CYP3A5*3 is the primary allelic variant in Chinese population. CYP3A5 genotypes are closely associated with blood CsA concentrations in hemopoietic stem cell transplant recipients, and CYP3A5*1/*1 requires a larger CsA dose to maintain the same blood concentration than does CYP3A5*1/*1. CYP3A5 genotyping by DHPLC may predict recipients' phenotype and CsA dose requirement.

[Expression and clonal proliferation of TCR Vbeta subfamilies of peripheral T-cells in acute myeloid leukemia patients].

This study was purposed to investigate the expression and clonal proliferation of receptor (TCR) Vbeta subfamilies of the T-cells in acute leukemic patients at different disease status (onset, complete remission or relapse) and to analyze the influence of the leukemic cell load on anti-leukemic effect of peripheral T-lymphocytes of the patients. Gene sequences of peripheral TCR Vbeta 24 families from 11 leukemic patients and 3 normal donors were expanded by RT-PCR. Genescan technique was applied to evaluate clonal expression of the TCRVbeta subfamilies, clonal characteristics of the CDR3 from peripheral blood of AML patients at different disease status. The application, clonal proliferation, cellular complexity of T-cells, and the variation of immunotypes of T-cells were compared. The results indicated that the lower and partial distribution of TCR Vbeta subfamily was found in all 11 patients when firstly diagnosed; the expression of TCR Vbeta subfamilies after induction in vitro increased; obvious elevation of TCR Vbeta subfamilies was observed in patients at complete remission although expression level was still lower than normal, whereas the significant descent of TCR Vbeta subfamilies was detected in 4 relapsed patients. Only 1 - 2 clonal proliferation of TCR Vbeta subfamilies existed in 9 out of 11 patients at initial diagnosis which increased at remission. The status of clonal proliferation of Vbeta subfamily T-cells continued regardless of any different disease status in most patients. There was an obvious decrease of CDR3 complexity at initial diagnosis or relapse, while CDR3 complexity would be partially improved at remission. It is concluded that the restrict distribution and expression of TCR Vbeta subfamilies were found in AML patients. Clonal proliferation of T-cells Vbeta subfamily continuously exists regardless of any different disease status in most patients. Some Vbeta subfamilies sustain clonal proliferation at different disease status. Some clonal proliferations of Vbeta subfamilies are associated with the effects of leukemic cells, CDR3 complexity obviously decreases under disease status which can be partially improved at remission.