Gambogic acid improves non-small cell lung cancer progression by inhibition of mTOR signaling pathway.

Gambogic acid (GA) has been shown to inhibit cancer cell proliferation, induce apoptosis, and enhance reactive oxygen species accumulation. However, whether GA could improve multidrug resistance through modulating autophagy has never been explored. We demonstrated that the combination of GA and cisplatin (CDDP) resulted in a stronger growth inhibition effect on A549 and NCI-H460 cells using the MTT assay. Furthermore, treatment with GA significantly increased autophagy in these cells. More importantly, GA-induced cell death could be largely abolished by 3-methyladenine (3-MA) or chloroquine (CQ) treatment, suggesting that GA-induced cell death was dependent on autophagy. Western blot analysis showed that GA treatment suppressed the activation of Akt, mTOR, and S6. In addition, using a GA and rapamycin combination induced more cell death compared to either GA or rapamycin alone. In summary, GA may have utility as an adjunct therapy for non-small cell lung cancer (NSCLC) patients through autophagy-dependent cell death, even when cancer cells have developed resistance to apoptosis.

Retinoblastoma binding protein 2 (RBP2) promotes HIF-1α-VEGF-induced angiogenesis of non-small cell lung cancer via the Akt pathway.

BACKGROUND: Pathological angiogenesis plays an essential role in tumor aggressiveness and leads to unfavorable prognosis. The aim of this study is to detect the potential role of Retinoblastoma binding protein 2 (RBP2) in the tumor angiogenesis of non-small cell lung cancer (NSCLC). METHODS: Immunohistochemical staining was used to detect the expression of RBP2, hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF) and CD34. Two pairs of siRNA sequences and pcDNA3-HA-RBP2 were used to down-regulate and up-regulate RBP2 expression in H1975 and SK-MES-1 cells. An endothelial cell tube formation assay, VEGF enzyme-linked immunosorbent assay, real-time PCR and western blotting were performed to detect the potential mechanisms mediated by RBP2 in tumor angiogenesis. RESULTS: Of the 102 stage I NSCLC specimens analyzed, high RBP2 protein expression is closely associated with tumor size (P = 0.030), high HIF-1α expression (P = 0.028), high VEGF expression (P = 0.048), increased tumor angiogenesis (P = 0.033) and poor prognosis (P = 0.037); high MVD was associated with high HIF-1α expression (P = 0.034), high VEGF expression (P = 0.001) and poor prognosis (P = 0.040). Multivariate analysis indicated that RBP2 had an independent influence on the survival of patients with stage I NSCLC (P = 0.044). By modulating the expression of RBP2, our findings suggested that RBP2 protein depletion decreased HUVECs tube formation by down-regulating VEGF in a conditioned medium. RBP2 stimulated the up-regulation of VEGF, which was dependent on HIF-1α, and activated the HIF-1α via phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway. Moreover, VEGF increased the activation of Akt regulated by RBP2. CONCLUSIONS: The RBP2 protein may stimulate HIF-1α expression via the activation of the PI3K/Akt signaling pathway under normoxia and then stimulate VEGF expression. These findings indicate that RBP2 may play a critical role in tumor angiogenesis and serve as an attractive therapeutic target against tumor aggressiveness for early-stage NSCLC patients.

A systematic review of risk factors for brain metastases and value of prophylactic cranial irradiation in non-small cell lung cancer.

BACKGROUND: The incidence of brain metastases (BM) varies in patients with non-small cell lung cancer (NSCLC), calls into question the value of prophylactic cranial irradiation (PCI). It is possible that clinicopathologic characteristics are associated with the development of BM, but these have yet to be identified in detail. Thus, we conducted the present meta-analysis on risk factors for BM and the value of PCI in patients with NSCLC. METHODS: Eligible data were extracted and the risk factors for BM and the value of PCI in patients with NSCLC were analyzed by calculating the pooled odds ratio (OR). Heterogeneity was detected using Q and I-squared statistics, and publication bias was tested by funnel plots and Egger's test. RESULTS: Six randomized controlled trials with a focus on the value of PCI and 13 eligible studies with a focus on risk factors for BM were included. PCI significantly reduced the incidence of BM in patients with NSCLC (p=0.000, pooled OR=0.34, 95% confidence interval = 0.37-0.59). Compared with non-squamous cell carcinoma, squamous cell carcinoma was associated with a low incidence of BM in patients with NSCLC (p=0.000, pooled OR=0.47, 95% confidence interval =0.34- 0.65). The funnel plot and Egger's test suggested that there was no publication bias in the current meta-analysis. CONCLUSIONS: This meta-analysis provides statistical evidence that compared with non-squamous cell carcinoma, squamous cell carcinoma can be used as a predictor for BM in patients with NSCLC, and PCI might reduce the incidence of BM in patients with NSCLC, but does not provide a survival benefit.

Lysosomal membrane protein TMEM192 deficiency triggers crosstalk between autophagy and apoptosis in HepG2 hepatoma cells.

As constituents of lysosomes, lysosomal membrane proteins play important roles in lysosome-related autophagy and apoptosis. In a recent proteomic study of lysosomal proteins, we identified transmembrane protein 192 (TMEM192) as a novel lysosomal membrane protein candidate. Using specific anti-TMEM192 antibody and lysosomal markers, the lysosomal localization of TMEM192 was determined by immunofluorescence. TMEM192 shows a wide expression pattern in mouse tissues. Interestingly, TMEM192 was found to be highly expressed in tumor cell lines, while it was not expressed or was detected at low levels in normal cell lines. By knockdown of TMEM192 expression using specific siRNAs, we found that TMEM192-deficient HepG2 hepatoma cells show growth inhibition and increased apoptosis. Autophagy was shown to be activated through detection of LC3II expression. Increased apoptosis was inhibited by blocking the expression of the key autophagy gene Atg7 in TMEM192-deficient HepG2 cells. The results suggest that TMEM192 is important for tumor cell growth and proliferation. TMEM192 deficiency can induce autophagy in tumor cells, and can further activate apoptosis by the mitochondrial pathway through autophagy. TMEM192 promotion of autophagy may be a new route for tumor therapy.

[Improvement of carbon tetrachloride drug-induced liver injury model in vitro].

OBJECTIVE: To establish an ideal CCl4 drug-induced liver injury model in vitro. METHOD: Traditional method and improved method were adopted for preparing CCl4 injury liquid and drug-induced human liver HepG2 cell injury. Cell morphological change was observed under a bright-field microscope. The level of alanine aminotransferase (ALT) in supernatant was detected by biochemical method. 4-Methyl-tetrazolium (MTT) chromatometry was adopted for determining cell activity. RESULT: The improved method showed better CCl4-induced injury effect than the traditional method. With the increase in the concentration of CCl4 injury liquid, the ALT level significantly increased, whereas the cell activity notably decreased. Particularly, 70% CCl4 injury liquid use for 4 hours could achieve the best injury effect. CONCLUSION: The improved method could be used to establish an ideal CCl4 drug-induced liver injury model in vitro, which can lay foundation for further in vitro studies.

Effects of rhubarb extract on radiation induced lung toxicity via decreasing transforming growth factor-beta-1 and interleukin-6 in lung cancer patients treated with radiotherapy.

BACKGROUND: Radiation induced lung toxicity (RILT) is the main adverse effect in the radiation therapy of lung cancer. However, the optimal management of RILT has not been defined. In this paper, we investigated the effects of rhubarb extract on RILT, pulmonary function (PF), transforming growth factor-beta-1 (TGF-beta1), and interleukin-6 (IL-6) in lung cancer patients treated with radiotherapy. PATIENTS AND METHODS: We conducted a randomized, double-blind, placebo-controlled trial. Eighty consecutive patients were randomly enrolled into two groups: trial group and control group. The trial group received three-dimensional conformal radiation therapy (3D-CRT) plus rhubarb (at a dose of 20 mg kg(-1) once a day) for 6 weeks. The control group received 3D-CRT plus a placebo containing starch for 6 weeks. Plasma TGF-beta1 and serum IL-6 were measured in all patients before, every 2 weeks during, and at 6 weeks after the completion of the treatment. RILT and PF were evaluated at 6 weeks and 6 months after the end of the treatment, respectively. The differences of TGF-beta1, IL-6, RILT, and PF between the two groups were analysed. RESULTS: The incidence of RILT in the trial group was significantly lower than that in the control group at 6 weeks and 6 months after treatment (32.4% versus 56.7% at week 6, and 27.0% versus 52.8% at month 6, both P<0.05). The plasma TGF-beta1 levels in the trial group were significantly lower than that in the control group during and after the treatment (P<0.05 or 0.01, respectively). The serum IL-6 levels in the trial group were significantly lower than that in the control group during the treatment (all P<0.01). The forced vital capacity (FVC), forced expiratory volume at 1s (FEV1) at 6 weeks and the diffusion capacity for carbon monoxide (DLCO) at 6 months in the trial group were significantly improved compared to the control group (P<0.05 or 0.01, respectively). CONCLUSIONS: The rhubarb extract significantly attenuated RILT and improved PF, probably by decreasing the level of TGF-beta1 and IL-6. These results may be of value for the prophylaxis of RILT, but the exact mechanisms underlying these prophylactic effects remain to be further explored.

[Accuracy and precision of X-ray radiosurgery treatment for tumors in eyeball].

BACKGROUND & OBJECTIVE: Localization error in X-ray radiosurgery for tumors in eyeball was common due to the rotation of eyeball. The accuracy and precision of X-ray radiosurgery was studied by fixing the eyeball with micro-vacuo-certo-contacting ophthalmophanto (MVCCOP) to reduce the error in this article. METHODS: CT localization accuracy of X-ray radiosurgery system was measured using special markers in skull phantom. The eyeballs were fixed using MVCCOP, which was designed by the authors, and then the eyeball fixation accuracy and target localization accuracy were measured by comparing the CT localization coordinates and verification coordinates of corresponding points. RESULTS: The mean error of CT localization of BRW head-ring was 0.65 mm and maximum error was 1.09 mm. The mean error of fixation of eyeball using MVCCOP was 0.84 mm and maximal error was 1.17 mm. The accuracy of tumor localization in eyeball was 0.87 mm averagely and 1.19 mm maximally. The mean error of SRS200 was 0.22 mm and maximum error was 0.32 mm. The total error was 1.40 mm and 95 percentile confidence error was 2.12 mm. CONCLUSION: The accuracy and precision of X-ray radiosurgery using MVCCOP has come up to the standard of quality control of stereotactic radiosurgery. This localization method can reduce the localization errors in radiosurgery caused by the rotation of eyeball.