Breviscapine reverses doxorubicin resistance in breast cancer and its related mechanisms.

BACKGROUND: Based on the effect of breviscapine (BRE) on reversing drug resistance of human breast cancer cell line MCF-7/doxorubicin (Dox), the mechanism was preliminarily explored. METHODS: The methyl thiazolyl tetrazolium (MTT) method was introduced to detect inhibitory effect of Dox alone or in combination with BRE on MCF-7 (M) and MCF-7/Dox (MD) cells, and the inhibitory concentration (IC50 ) was obtained. Cell apoptosis and Dox concentration was assessed by flow cytometry. The drug resistance multiple and reversal fold were calculated. Western blot was performed to evaluate the expression of Bcl-2, Bax, EGFR, p-EGFR, P-gp, caspase-3, and cleaved-caspase-3 protein in cells. The efflux of Rho-123 was measured by flow cytometry and fluorescence microscopy. RESULTS: The IC50 of Dox on MD and M cells was 16.67 and 0.71 µg/mL, respectively, with a drug resistance ratio of 23.48 times. The IC50 of Dox combined with BRE on MD cells was 5.62 µg/mL, with a reversal ratio of 2.97 times. BRE greatly enhanced Dox-induced apoptosis of MD cells. Bax and cleaved-caspase-3 (proapoptotic protein) expression were obviously increased, while Bcl-2 (antiapoptotic protein) expression was significantly decreased after BRE treatment. BRE inhibited EGFR activation and P-gp expression. BRE increased the intracellular accumulation of Dox in MD cells by P-gp. CONCLUSION: BRE could increase the MD sensitivity to Dox via increasing Bax and cleaved-caspase-3 expression and inhibiting Bcl-2 expression, thereby promoting cell apoptosis. BRE reversed Dox resistance of MD cells by increasing Dox intracellular accumulation through inhibiting P-gp expression via EGFR.

Significance of immunogenic cell death-related genes in prognosis prediction and immune microenvironment landscape of patients with cutaneous melanoma.

Cutaneous melanoma (CM) is one of the most life-threatening tumors. Although targeted therapies and immune checkpoint inhibitors have significantly improved patient outcomes over the past decades, they still have their efficacy limitations. Immunogenic cell death (ICD) induces regulated cell death through immunogenic signal secretion and exposure. Accumulated evidence suggests that the ICD process is an effective target for the treatment of a variety of tumor types, including CM. However, the research on ICD in CM is far from complete, and its clinical value has not been widely concerned. By analyzing the Cancer Genome Atlas (TCGA) database, we constructed a new risk model based on 4 ICD-related genes and validated its ability to predict the prognosis of CM patients. In addition, we comprehensively analyzed the tumor microenvironment (TME) of CM patients and showed a significant immunosuppressive TME in the high-risk group compared with the low-risk group. By Immunophenoscore (IPS), we further explored the correlation between the model and immunotherapy response. The data of Genomics of Drug Sensitivity in Cancer (GDSC) database were further extracted to analyze drug sensitivity and evaluate its correlation with the established risk model. In the end, differential expressed genes (DEGs) were analyzed by Gene Set Variation Analysis (GSVA) to preliminarily explore the possible signaling pathways related to the prognosis of ICD and CM. The results of this study provide new perspectives and insights for individualized and accurate treatment strategies for CM patients.

Differential effects of recombinant human endostatin treatment on differentiated and undifferentiated blood vessels in Lewis lung cancer.

In the present study, we evaluated the effects of recombinant human (rh-)endostatin treatment on differentiated and undifferentiated tumor vasculature in Lewis lung cancer for the first time. Lewis lung carcinoma models were established. The animals were treated daily with varying doses of rh-endostatin or physiological saline for 14 days. Intravital microscopy was performed following treatment. The expression of CD31 and CD34 was determined by immunohistochemical staining, and microvessel density (MVD) was determined. Rh-endostatin treatment significantly decreased the tumor volume compared with the control group. Rh-endostatin treatment normalized the architecture of the vascular network. CD31+ cells decreased following rh-endostatin treatment, whereas CD34+ cells were unaffected by the treatment. Accordingly, the MVD value of CD31+ cells in rh-endostatin treatment groups significantly decreased (P<0.01), and the MVD value of CD34+ cells in the rh-endostatin treatment groups did not decrease. Undifferentiated tumor blood vessels were significantly inhibited by rh-endostatin treatment. In conclusion, the normalization of the tumor vasculature by endostatin may be related to the differential effects of endostatin on differentiated and undifferentiated blood vessels.

Developing an effective therapeutic by delivery of synthetic microRNA-520e in lung cancer treatment.

MicroRNAs (miRNAs) can function as tumor suppressors and might provide an efficient strategy for annihilating cancer. Specific miRNAs can be reintroduced into tumor cells to complement the loss of tumor suppression activities. The "miRNA replacement therapy" is based on the concept that the reintroduction of miRNAs depleted in cancer cells reactivates cellular pathways that lead to therapeutic responses. Here, we report the development of miRNA delivery formulation using synthesized miR-520e. This formulation proved to be effective either locally or systematically. MiR-520e accumulation becomes evident in tumor cells and then exerts anti-proliferative function. Meanwhile, intravenous delivery of formulated miR-520e does not induce any deregulation in cytokine levels and liver enzymes. Taken together, our results shed new lights on the concept that systematic delivery of synthetic mimics for tumor suppressor miR-520e and provide potential implications for miRNA therapy in clinic.

Association of CHRNA5-A3-B4 variation with esophageal squamous cell carcinoma risk and smoking behaviors in a Chinese population.

BACKGROUND: CHRNA5-A3-B4, the gene cluster encoding nicotinic acetylcholine receptor subunits, is associated with lung cancer risk and smoking behaviors in people of European descent. Because cigarette smoking is also a major risk factor for esophageal squamous cell carcinoma (ESCC), we investigated the associations between variants in CHRNA5-A3-B4 and ESCC risk, as well as smoking behaviors, in a Chinese population. METHODS: A case-control study of 866 ESCC patients and 952 healthy controls was performed to study the association of polymorphisms (rs667282 and rs3743073) in CHRNA5-A3-B4 with cancer risk using logistic regression models. The relationships between CHRNA5-A3-B4 polymorphisms and smoking behaviors that can be quantified by cigarettes smoked per day (CPD) and pack-years of smoking were separately estimated with Kruskal-Wallis tests among all 840 smokers. RESULTS: CHRNA5-A3-B4 rs667282 TT/TG genotypes were associated with significantly increased risk of ESCC [adjusted odds ratio (OR) = 1.32, 95% confidence interval (CI) = 1.03 - 1.69, P = 0.029]. The increased ESCC risk was even higher among younger subjects (≤60 years) (OR = 1.44, 95% CI = 1.04 - 1.98, P = 0.024). These effects were not found in another polymorphism rs3743073. No evident association between the two polymorphisms and smoking behaviors was observed. CONCLUSIONS: These results support the hypothesis that CHRNA5-A3-B4 is a susceptibility gene cluster for ESCC. The relationship between CHRNA5-A3-B4 and smoking behaviors in a Chinese population needs further investigation.

NVP-BEZ235, dual phosphatidylinositol 3-kinase/mammalian target of rapamycin inhibitor, prominently enhances radiosensitivity of prostate cancer cell line PC-3.

BACKGROUND: Aberrant activation of phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway may account for development of radioadaptation and is not rare in prostate cancer. Neither PI3K nor mTOR blockade could completely inhibit the pathway owing to paradoxical feedback, so we anticipate dual PI3K/mTOR blockade by NVP-BEZ235 to radiosensitize prostate cancer cells. METHODS: We investigated into the radiosensitizing effect of NVP-BEZ235 on PC-3 cells, which are devoid of androgen receptors. Clonogenic survival and MTT assays were performed, and to pursue underlying cellular changes flow cytometric analysis of cell cycle and apoptosis as well as western blot were carried out. RESULTS: Exposure to NVP-BEZ235 and irradiation caused a greater degree of survival inhibition than ionizing radiation (IR) or BEZ235 alone. Dual PI3K/mTOR blockade along with IR induced a G2/M arrest and enhanced proapoptotic effect. NVP-BEZ235 radiosensitized PC-3 cells through counteracting constitutive as well as IR-triggered activation of Akt/mTOR signaling. CONCLUSIONS: Our study demonstrated that the dual PI3K/mTOR inhibitor NVP-BEZ235 prominently improved the radiosensitivity of PC-3 cells. It sensitized tumor cells to irradiation via interruption of cell cycle progression and augmentation of cell apoptosis, which was due to its constraint on constitutive and IR-elicited PI3K/Akt/mTOR signaling activation.

Is susceptibility locus for lung cancer in the 15q25 nicotinic acetylcholine receptor gene cluster CHRNA5-A3-B4 associated with risk of gastric cancer?

An association between common variants in the 15q25 nicotinic acetylcholine receptor (nAChR) gene cluster CHRNA5-A3-B4 (responsible for encoding nAChR subunits) and lung cancer risk has recently been reported in both Caucasian and Chinese population. Cigarette smoking is one of the major risk factors for both lung and gastric cancer. Moreover, nAChR plays an important role in cigarette smoke-related lung carcinogenesis as well as gastric cancer. Nevertheless, no study has evaluated the association between CHRNA5-A3-B4 gene cluster variants (rs667282 and rs3743073, two variants modifying lung cancer risk) and risk of gastric cancer. We genotyped these two single nucleotide polymorphisms(SNPs) and analyzed their associations with risk of gastric cancer in a case-control study of 637 gastric cancer patients and 855 healthy individuals matched by age and sex in a Chinese Han population. The differences in genotype distribution of the two SNPs (rs667282, rs3743073) between the cases and controls were not statistically significant (p = 0.468 and p = 0.495, respectively). Overall, we did not observe a significant association of each genotype of the two SNPs with risk of gastric cancer (TT/CT vs. CC: adjusted OR = 1.12,95 % CI = 0.86-1.45; p = 0.401 for rs667282 and GG/TG vs. TT: adjusted OR = 1.13,95 % CI = 0.90-1.43; p = 0.300 for rs3743073).The results of our study indicated that these two SNPs at the 15q25 locus did not modify gastric cancer risk and the reported risk SNP at 15q25 may be specific to lung cancer. Additional larger studies are needed to further confirm our findings.