Promotion of Lung Cancer Metastasis by SIRT2-Mediated Extracellular Protein Deacetylation.

Acetylation of extracellular proteins has been observed in many independent studies where particular attention has been given to the dynamic change of the microenvironmental protein post-translational modifications. While extracellular proteins can be acetylated within the cells prior to their micro-environmental distribution, their deacetylation in a tumor microenvironment remains elusive. Here it is described that multiple acetyl-vWA domain-carrying proteins including integrin ß3 (ITGB3) and collagen 6A (COL6A) are deacetylated by Sirtuin family member SIRT2 in extracellular space. SIRT2 is secreted by macrophages following toll-like receptor (TLR) family member TLR4 or TLR2 activation. TLR-activated SIRT2 undergoes autophagosome translocation. TNF receptor associated factor 6 (TRAF6)-mediated autophagy flux in response to TLR2/4 activation can then pump SIRT2 into the microenvironment to function as extracellular SIRT2 (eSIRT2). In the extracellular space, eSIRT2 deacetylates ITGB3 on aK416 involved in cell attachment and migration, leading to a promotion of cancer cell metastasis. In lung cancer patients, significantly increased serum eSIRT2 level correlates with dramatically decreased ITGB3-K416 acetylation in cancer cells. Thus, the extracellular space is a subcellular organelle-like arena where eSIRT2 promotes cancer cell metastasis via catalyzing extracellular protein deacetylation.

Increasing the frequency of CIK cells adoptive immunotherapy may decrease risk of death in gastric cancer patients.

AIM: to analyze the correlation between cytokine-induced killer (cik) cells adoptive immunotherapy and cancer-related death in gastric cancer patients. methods: One hundred and fifty-six gastric cancer patients after operation at the Third Affiliated Hospital of Soochow University were enrolled in this study. Their clinical data including demographic characteristics, operation time, tumor size, pathological type and staging, tumor metastasis, outcome of chemotherapy or CIK cells adoptive immunotherapy, survival time or time of death were collected with a standard structured questionnaire. Kaplan-Meier method was used to estimate the median survival time, and the 2- and 5- year survival rates. Hazard risk (HR) and 95% confidence interval (95% CI) of CIK cells adoptive immunotherapy for gastric cancer were calculated using the two-stage time-dependent covariates Cox model. RESULTS: the survival time of gastric cancer patients was longer after CIK cells adoptive immunotherapy than after chemotherapy (χ(2) = 10.907, P = 0.001). The median survival time of gastric cancer patients was also longer after CIK cells adoptive immunotherapy than after chemotherapy (49 mo vs 27 mo, P < 0.05). The 2- and 5-year survival rates of gastric cancer patients were significantly higher after CIK cells adoptive immunotherapy than after chemotherapy (73.5% vs 52.6%, 40.4% vs 23.9%, P < 0.05). A significant difference was observed in the survival curve for patients who received CIK cells adoptive immunotherapy (0, 1-10, 11-25, and over 25 frequencies) (χ(2) = 14.534, P = 0.002). The frequencies of CIK cells adoptive immunotherapy were significantly related with the decreasing risk of death in gastric cancer patients after adjustment for sex and age of the patients, tumor stage and relapse (HR = 0.54, 95% CI: 0.36-0.80) when the first stage Cox model was used to define the subjects who remained alive beyond 36 mo as survivors. However, no correlation was observed between the frequencies of death in CIK cells adoptive immunotherapy and the risk of gastric cancer patients (HR = 1.09, 95% CI: 0.63-0.89) when the second stage Cox model was used to define the subjects who survived for more than 36 mo as survivors. CONCLUSION: the survival time of the gastric cancer patients treated with chemotherapy combined with CIK cells adoptive immunotherapy is significantly longer than that of the patients treated with chemotherapy alone and increasing the frequency of CIK cells adoptive immunotherapy seems to benefit patients more.

[In vitro and in vivo inhibitory effect of Ad-ING4 gene on proliferation of human prostate cancer PC-3 cells].

BACKGROUND AND OBJECTIVE: Adenovirus vector has been widely used in tumor gene therapy. ING4 is a member of growth inhibiting factors and a potent anti-tumor gene which could induce apoptosis of many tumor cells. This study was to investigate the inhibitory effects of adenovirus-mediated ING4 (Ad-ING4) gene on the proliferation of human prostate cancer PC-3 cells in vitro and in vivo, and to explore its mechanisms. METHODS: Ad-ING4 was obtained by virus-amplification technique. After transfection of purified Ad-ING4 into PC-3 cells, the expression of ING4 was detected by reverse transcription-polymerase chain reaction(RT-PCR); the influence of Ad-ING4 transfection on cell proliferation was evaluated using MTT assay. Cell apoptosis was assessed using Hoechst33258 staining and flow cytometry. RT-PCR was performed to detect the mRNA levels of the transcription of apoptosis-related genes such as bcl-2, bax, p53, and caspase-3. Athymic nude mice bearing PC-3 tumors were intratumorally injected with Ad-ING4 (100 microL, 1x10(9) pfu/mL). Tumor growth was recorded. All nude mice were killed at the end of the experiment to observe the growth of xenografts. The expressions of Bcl-2, Bax, Caspase-3, and CD34 proteins in tumor tissues were detected by immunohistochemistry. RESULTS: Human ING4 gene was successfully transcribed in PC-3 cells and induced apoptosis by up-regulating p53, bax, caspase-3 expression and down-regulating bcl-2 expression. Inhibition of cell proliferation was significant in PC-3 cells. Tumor growth was significantly inhibited in the Ad-ING4 group as compared with that in the Ad-GFP group and the PBS group (P<0.05). The weight inhibitory rate was 37.0% in the Ad-ING4 group. The expressions of Bax and Caspase-3 were up-regulated, and the expressions of Bcl-2 and CD34 were down-regulated in the Ad-GFP group. CONCLUSIONS: Adenovirus-mediated ING4 gene exhibits anti-tumor ability in human prostate cancer PC-3 cells in vitro and in vivo, and induces apoptosis. This may be related to the up-regulations of p53, bax, Caspase-3 and down-regulation of bcl-2.