盐霉素增加鼻咽癌CNE-2细胞放疗敏感性的实验研究

目的:探讨盐霉素（Sal）对鼻咽癌CNE-2细胞的放疗增敏作用及其可能的机制。方法:CCK8测定不同浓度盐霉素、不同剂量放疗及联合应用对CNE-2细胞增殖的抑制作用;平板克隆实验观察盐霉素联合放疗后细胞的克隆形成率;Hoechst33258染色观察细胞凋亡;流式细胞术检测细胞凋亡率及细胞周期的变化情况。结果:CCK8结果显示,盐霉素和放疗对鼻咽癌CNE-2细胞的生长有显著的抑制作用,呈浓度和剂量依赖性,且联合组抑制作用强于单纯药物组或放疗组。平板克隆实验显示盐霉素联合放疗后能显著降低细胞的克隆形成率;Hoechst33258染色显示盐霉素联合放疗治疗后细胞凋亡现象更明显;细胞流式术检测显示联合组较单纯药物组或放疗组凋亡率增加,盐霉素对放疗具有增敏作用。药物组和放疗组均能使G2/M期细胞比例增加,两者联合效果更明显。结论:盐霉素能增加人鼻咽癌CNE-2细胞的放疗敏感性,其作用机制可能与周期阻滞及其凋亡诱导相关。     

Salinomycin inhibits prostate cancer growth and migration via induction of oxidative stress

Background:

We have shown that a sodium ionophore monensin inhibits prostate cancer cell growth. A structurally related compound to monensin, salinomycin, was recently identified as a putative cancer stem cell inhibitor.

Methods:

The growth inhibitory potential of salinomycin was studied in a panel of prostate cells. To get insights into the mechanism of action, a variety of assays such as gene expression and steroid profiling were performed in salinomycin-exposed prostate cancer cells.

Results:

Salinomycin inhibited the growth of prostate cancer cells, but did not affect non-malignant prostate epithelial cells. Salinomycin impacted on prostate cancer stem cell functions as evidenced by reduced aldehyde dehydrogenase activity and the fraction of CD44⁺ cells. Moreover, salinomycin reduced the expression of MYC, AR and ERG, induced oxidative stress as well as inhibited nuclear factor-κB activity and cell migration. Furthermore, profiling steroid metabolites revealed increased levels of oxidative stress-inducing steroids 7-ketocholesterol and aldosterone and decreased levels of antioxidative steroids progesterone and pregnenolone in salinomycin-exposed prostate cancer cells.

Conclusion:

Our results indicate that salinomycin inhibits prostate cancer cell growth and migration by reducing the expression of key prostate cancer oncogenes, inducing oxidative stress, decreasing the antioxidative capacity and cancer stem cell fraction.     

Antiproliferative Activity of Polyether Antibiotic – Cinchona Alkaloid Conjugates Obtained via Click Chemistry

A series of eight new conjugates of salinomycin or monensin and Cinchona alkaloids were obtained by the Cu(I)‐catalysed 1,3‐dipolar Huisgen cycloaddition (click chemistry) of respective N‐propargyl amides of salinomycin or monensin with four different Cinchona alkaloid derived azides. In vitro antiproliferative activity of these conjugates evaluated against three cancer cell lines (LoVo, LoVo/DX, HepG2) showed that four of the compounds exhibited high antiproliferative activity (IC₅₀ below 3.00 μm ) and appeared to be less toxic and more selective against normal cells than two standard anticancer drugs.     

HDAC inhibitors enhance the lethality of low dose salinomycin in parental and stem-like GBM cells

The present studies determined whether the antibiotic salinomycin interacted with HDAC inhibitors to kill primary human GBM cells. Regardless of PTEN, ERBB1, or p53 mutational status salinomycin interacted with HDAC inhibitors in a synergistic fashion to kill GBM cells. Inhibition of CD95/Caspase 8 or of CD95/RIP-1/AIF signaling suppressed killing by the drug combination. Salinomycin increased the levels of autophagosomes that correlated with increased p62 and LC3II levels; valproate co-treatment correlated with reduced LC3II and p62 expression, and increased caspase 3 cleavage. Molecular inhibition of autophagosome formation was protective against drug exposure. The drug combination enhanced eIF2α phosphorylation and decreased expression of MCL-1 and phosphorylation of mTOR and p70 S6K. Activation of p70 S6K or mTOR promoted cell survival in the face of combined drug exposure. Overexpression of BCL-XL or c-FLIP-s was protective. Collectively our data demonstrate that the lethality of low nanomolar concentrations of salinomycin are enhanced by HDAC inhibitors in GBM cells and that increased death receptor signaling together with reduced mitochondrial function are causal in the combinatorial drug necro-apoptotic killing effect.     

盐霉素纳米制剂的研究进展

盐霉素（salinomycin,SAL）作为一种抗生素,已广泛用于畜牧业,近年来研究人员发现该药对多种肿瘤及肿瘤干细胞具有较强的抑制作用,而且体内外研究及早期临床试验结果均表明SAL具有抗肿瘤多重耐药活性,有望成为一种新型的抗肿瘤药物。但是,SAL的水溶性较差,且有一定的毒副作用,为获得更好的治疗效果,SAL制剂学的研究得到药学界的广泛关注。本文对近年来SAL纳米制剂的研究进展进行综述。     

Combinatorial treatment of mammospheres with trastuzumab and salinomycin efficiently targets HER2-positive cancer cells and cancer stem cells

A major obstacle in the successful treatment of cancer is the occurrence of chemoresistance. Cancer cells surviving chemotherapy and giving rise to a recurrence of the tumor are termed cancer stem cells and can be identified by elevated levels of certain stem cell markers. Eradication of this cell population is a priority objective in cancer therapy. Here, we report elevated levels of stem cell markers in MCF-7 mammospheres. Likewise, an upregulation of HER2 and its differential expression within individual cells of mammospheres was observed. Sorting for HER2^high and HER2^low cells revealed an upregulation of stem cell markers NANOG, OCT4 and SOX2 in the HER2^low cell fraction. Accordingly, HER2^low cells also showed reduced proliferation, ductal-like outgrowths and an increased number of colonies in matrigel. Xenografts from subcutaneously injected HER2^low sorted cells exihibited earlier onset but slower growth of tumors and an increase in stem cell markers compared to tumors developed from the HER2^high fraction. Treatment of mammospheres with salinomycin reduced the expression of SOX2 indicating a selective targeting of cancer stem cells. Trastuzumab however, did not reduce the expression of SOX2 in mammospheres. Furthermore, a combinatorial treatment of mammospheres with trastuzumab and salinomycin was superior to single treatment with each drug. Thus, targeting HER2 expressing tumors with anti-HER2 therapies will not necessarily eliminate cancer stem cells and may lead to a more aggressive cancer cell phenotype. Our study demonstrates efficient killing of both HER2 positive cells and cancer stem cells, hence opening a possibility for a new combinatorial treatment strategy.     

盐霉素增强长春新碱诱导急性T淋巴细胞白血病Jurkat细胞株凋亡研究

目的:本文旨在研究长春新碱(vincristine,VCR)与盐霉素(salinomycin,Sal)联合作用对急性T淋巴细胞白血病jurkat细胞株增殖、凋亡的影响及其可能的机制。方法:CCK-8法检测细胞增殖情况;流式细胞术检测各实验组细胞凋亡率;Western blot检测凋亡相关蛋白BCL-2、caspase-3和caspase-8表达水平。结果:VCR、Sal单独及联合处理Jurkat细胞株均显示出明显的增殖抑制作用,两药联合使用的增殖抑制作用更显著(P0.05),具有协同作用。联合用药组BCL-2蛋白水平较VCR和Sal单独处理组明显减少,而caspase-3和caspase-8水平明显增高;VCR和Sal联合用药组细胞凋亡率较VCR和Sal单独处理组明显提高(P0.05)。结论:长春新碱联合盐霉素作用于Jurkat细胞具有协同抑制增殖及诱导凋亡的作用。