ABSTRACT
OBJECTIVE@#To study the inhibitory effect of HDAC6 on proliferation of human leukemia KG1α and to explore its mechanism by ERK signaling pathways.@*METHODS@#.The siRNA interference technology was used to inhibit the HDAC6 gene expression; the expression of HDAC6 and prateins of ERK signal pathway was detected by Western blot; the cell proliferation ability was detected by colony forming experiment and trypan blue staining; cell cycle was detected by FCM; and the expression of Ki67 was detected by immunofluorescence.@*RESULTS@#Western blot showed that HDAC6 expression was up-regulated in leukemia cell lines in comparison with the healthy volunteers and bone marrow stromal cells (P＜0.05). Knockdown of HDAC6 significantly inhibited the proliferation and colony formation ability of leukemia cells, promoted cell arrest at G/G phase. The Western blot and immunefluorescence showed that knockdown of HDAC6 suppressed the expression level of Ki67, CDK4, Cyclin D1 and enhanced the expression level of p16, p21, p-ERK (P＜0.05).@*CONCLUSION@#Knockdown of HDAC6 significantly inhibits the proliferation, arrest the cell cycle at G/G phase, and its mechanism probably relates with the activation of ERK signaling pathway.
ABSTRACT
Objective Programmed death-ligand 1 (PD-L1) is essential in the immune escape of colorectal cancer (CRC) cells. In this study, we investigated the disease-free survival (DFS) and overall survival (OS) of CRC patients receiving capecitabine-based adjuvant chemotherapy after RO resection. Methods This retrospective study included 265 CRC patients treated by RO resection and postoperative capecitabine-based adjuvant chemotherapy in Zhengzhou People′s Hospital between January 1, 2010 and December 12, 2017. We analyzed the clinical data, performed genotyping of the genetic variants and determined the expression of PD-L1 mRNA in the CRC tissue. We also analyzed the correlation between the genetic polymorphisms and other baseline characteristics by chi-square test, the expression of PD-L1 mRNA in different genotypes by non-parametric test, and the prognosis using the Kaplan-Meier method, followed by multivariate Cox regression analysis for adjustment. Results The median DFS and OS of the 265 CRC patients were 4.6 and 6.5 years, respectively. Three single nucleotide polymorphisms of the PD-L1 gene, 901T>C, -1813G>C and -1457T>A, were identified in the NCBI database with the minor allele frequency >10% in the Chinese population, of which, only 901T>C was of clinical significance in the outcome analysis. 901T>C was located in the intron region of the PD-L1 gene, with the genotypes of TT in 185 cases (69.81%), TC in 72 (27.17%) and CC in 8 (3.02%). The minor allele frequency was 0.17 and the distribution frequencies of all the three genotypes conformed to the Hardy-Weinberg equilibrium (P = 0.758). The median DFS was significantly longer in the CRC patients with the TT genotype than in those with the TC or CC genotype (4.8 vs 3.5 years, P = 0.001), and so was the median OS (6.7 vs 4.7 years, P < 0.001). The adjustment of OS by multivariate Cox regression analysis showed that the TC and CC genotypes were an independent factor for OS (OR = 1.89, P = 0.006). The analysis of 89 of the CRC tissue specimens revealed a markedly higher expression of PD-L1 mRNA in the patients with the TC or CC genotype than in those with the TT genotype (P < 0.001). Conclusion The 901T>C polymorphism of the PD-L1 gene may influence the clinical outcomes of the CRC patients receiving capecitabine-based adjuvant chemotherapy by mediating the expression of PD-L1 mRNA.
ABSTRACT
OBJECTIVE@#To study the promoting-apoptosis effect of HDAC6 on the human leukemia cells and its mechanism.@*METHODS@#The siRNA interference technology was used to inhibit the expression of HDAC6 gene, the RT-PCR and Western blot were used to detect the expression of HDAC6 and related signal pathway proteins respectively, the flow cytometry and Hoechest staining were used to detect the apoptosis and morphology changes of K562 cells.@*RESULTS@#Compared with the periphal blood monocyte and bone marrow stromal cells of healthy volunteers, the expression level of HDAC6 in leukemia cell lines was up-regulated significantly(P<0.05); the flow cytometry and Hoechest staining showed that after interference of HDAC6 gene, the apoptosis of K562 cells increased, moreover the cell morphology was changed; the Western blot detection showed that the interfering HDAC6 increased BAX/BCL-2 ratio and cleaved caspase 3 expression, and activated the MAPK, ATK, ERK signaling pathway.@*CONCLUSION@#The interferance of HDAC6 can promote the K562 cell apoptosis, its mechanism may relate with activation of MAPK signaling pathway.