ABSTRACT
This study examined the synergetic effect of class IA Phosphoinositide 3-kinases catalytic subunit p110β knockdown in conjunction with oxaliplatin treatment on colon cancer cells.Down-regulation of p110β by siRA interference and oxaliplatin treatment were applied in colon cancer cell lines HT29,SW620 and HCT116.MTT assay was used to measure the inhibitory effect of p110 knockdown on the proliferation of colon cancer cell lines.SubG1 assay and Annexin-V FITC/PI double-labeling cytometry were applied to detect cell apoptosis.And cell cycle was evaluated by using PI staining and flow cytometry.The expression of caspase 3,cleaved PARP,p-Akt,T-Akt and p 110β was dctermined by western blotting.The results suggested that down-regulation of p110β expression by siRNA obviously reduced cell number via accumulation in G0-G1 phase of the cell cycle in the absence of notablely increased apoptosis in colon cancer cell lines HT29 and SW620 (S phase arrest in -HCT116).Moreover,inhibition of p110β expression increased oxaliplatin-induced cell apoptosis and cell cycle arrest in HT29,HCT116 and SW620 cell lines.In addition,increases of cleaved caspase-3 and cleaved PARP induced by oxaliplatin treatment were determined by immunoblotting in p110β knockdown group compared with normal control group and wild-type group.It is concluded that down-regulated expression of p110β could inhibit colon cancer cells proliferation and result in increased chemosensitivity of colorectal cancer cells to oxaliplatin through augmentation of oxaliplatin-induced cell apoptosis and cell cycle arrest.
ABSTRACT
DNA damage response (DDR) in different cell cycle starus of human peripheral blood lymphocytes (PBLs) and the role of H2AX in DDR were investigated.The PBLs were stimulated into cell cycle with phytohemagglutinin (PHA).The apoptotic ratio and the phosphorylation H2AX (S139)were flow cytometrically measured in resting and proliferating PBLs after treatment with camptothecin (CPT) or X-ray.The expressions of γH2AX,Bcl-2,caspase-3 and caspase-9 were detected by Western blotting.DDR in 293T cells was detected after H2AX was silenced by RNAi method.Our results showed that DNA double strand breaks (DSBs) were both induced in quiescent and proliferating PBLs after CPT or X-ray treatment.The phosphorylation of H2AX and apoptosis were more sensitive in proliferating PBLs compared with quiescent lymphocytes (P＜0.05).The expression levels of anti-apoptotic proteins Bcl-2 were reduced and cleaved caspase-3 and caspase-9 were increased.No significant changes were observed in CPT-induced apoptosis in 293T cells between H2AX knocking down group and controls.It was concluded that proliferating PBLs were more vulnerable to DNA damage compared to non-stimulated lymphocytes and had higher apoptosis rates.γH2AX may only serve as a marker of DNA damage but exert no effect on apoptosis regulation.
ABSTRACT
This study examined the role of regulated upon activation normal T cell expressed and secreted (RANTES) and its receptor C-C chemokine receptor type 5 (CCR5) in gastric cancer metastasis and the associated mechanism.The expression of RANTES and CCR5 was detected by using immunohistochemical staining and Western blotting in the gastric cancer tissues obtained from 60 gastric cancer patients with or without lymph node metastasis (n=30 in each).The results showed that the expression levels of RANTES and CCR5 were higher in gastric cancer with lymph node metastasis than in that without metastasis (P＜0.05).The expression levels of RANTES in 30 lymph nodes with cancerous invasion were higher than in 30 normal lymph nodes (P＜0.05).Chemotactic test revealed that the number of migrating gastric cancer cells (n=295.0±54.6) induced by the protein of cancer-invading lymph nodes was greater than that by the protein mixture from cancer-invading lymph nodes and RANTES antibody (n=42.5+11.6) (P＜0.05).RT-PCR showed that the expression levels of the main Th1 cytokines (IL-2,γ-IFN) were lower in gastric cancer with lymph node metastasis (2.22±0.90,3.26±1.15 respectively)than in that without metastasis (3.07±1.67,4.77±1.52 respectively) (P＜0.05),but the expression level of the main Th 2 cytokine (IL-10) was higher in gastric cancer with lymph nodes metastasis (6.06±2.04)than in that without metastasis (4.88±1.87) (P＜0.05).It was concluded that RANTES and its receptor CCR5 may contribute to gastric cancer metastasis through influencing the balance of Th1/Th2.RANTES and CCR5 may become a marker of gastric cancer metastasis.
ABSTRACT
Little is reported about the role of PTEN gene in the progression and prognosis of GISTs.This study examined the clinical implications of the tumor suppressor gene PTEN as a prognostic factor in the GISTs.Immunohistological staining and immunoblotting were employed to examine the PTEN protein expression,and its association with clinical measures.Clinicopathological features were reviewed by a retrospective examination of medical records.Reduced PTEN expression was significantly associated with tumor diameter,mitotic figure count,metastasis and pathological stage of tumor(P<0.05),and was not correlated with age,gender and tumor location(P>0.05).The 3-year survival rate of the patients with reduced PTEN expression was significantly lower than those with high PTEN expression(P<0.01).These results suggest that the expression of PTEN gene was significantly linked with the progression and metastasis of GISTs and it is an independent prognostic factor.
ABSTRACT
In order to examine the effect of GRIM 19 on colon cancer cell SW480, the recombinant adenovirus carrying GRIM19 gene was constructed and transfected into SW480 cells. GRIMI9 cDNA was amplified by PCR with the template pcxn2-GRlMl9 and cloned into the shuttle plasmid pAdTrack-CMV. The plasmid pAdTrack-CMV-GRIM19 was linearized by PmeI and homologously recombined with bone plasmid pAdEasy-1 in BJ5183, followed by identification by enzyme diges- tion. After transfection of linearized pAd-GRIM19 with PacI into HEK293 cells, Ad-GRIMI9 was obtained and amplified by 3 circles. SW480 cells were infected with Ad-GRIM19. The apoptosis rate was detected by flow cytometry. Agarose electrophoresis revealed the bands of recombinant plasmids identified by enzyme digestion were in the right range corresponding with expectation. Under the fluorescent microscopy, the package of Ad-GRIM19 in HEK293 cells and the expression of Ad-GRIM19 in SW480 cells were observed. The transfection of Ad-GRIM19 into SW480 cells in-creased the apoptosis rate of SW480 cells as compared with controls. It was concluded that Ad-GRIM19 was successfully constructed and the overexpression of GRIM19 in colon cancer cell lines could promote the apoptotic cell death.