circRNA MYO1C对肺癌细胞自噬和肿瘤干细胞分化的影响

目的 探讨环状RNA(circRNA)MYO1C对非小细胞肺癌(NSCLC)细胞自噬和肿瘤干细胞(Cancer stem cells,CSCs)分化的影响。方法 通过RT-qPCR检测正常肺上皮细胞和NSCLC A549细胞中circRNA MYO1C水平。将A549分为对照组、NC组和siMYO1C组,通过转染si-circRNA MYO1C质粒干扰circRNA MYO1C。用CCK-8法和Transwell实验检测细胞生长活力和迁移能力。通过Western blot检测CSCs分化标志蛋白(OCT4、SOX2和NANOG)以及自噬标志蛋白(P62和IC3II/LC3I)的表达水平。结果 相对正常肺上皮细胞,circRNA MYO1C在A549细胞中表达明显上调(0.99±0.06 vs. 4.87±0.88,P=0.002)。与NC组比较,siMYO1C组细胞中circRNA MYO1C水平、细胞活力、迁移、OCT4、SOX2、NANOG和IC3II/LC3I蛋白水平显著降低,而P62蛋白水平显著升高(P＜0.001)。结论 下调circRNA MYO1C能够抑制NSLCLC细胞的CSCs分化和自噬相关蛋白表达,并抑制肺癌细胞迁移。     

4EGI-1 targets breast cancer stem cells by selective inhibition of translation that persists in CSC maintenance,proliferation and metastasis

Cancer death is a leading cause of global mortality. An estimated 14.1 million new cancer cases and 8.2 million cancer deaths occurred worldwide in 2012 alone. Cancer stem cells (CSCs) within tumors are essential for tumor metastasis and reoccurrence, the key factors of cancer lethality. Here we report that 4EGI-1, an inhibitor of the interaction between translation initiation factors eIF4E1 and eIF4G1 effectively inhibits breast CSCs through selectively reducing translation persistent in breast CSCs. Translation initiation factor eIF4E1 is significantly enhanced in breast CSCs in comparison to non-CSC breast cancer cells. 4EGI-1 presents increased cytotoxicity to breast CSCs compared to non-CSC breast cancer cells. 4EGI-1 promotes breast CSC differentiation and represses breast CSC induced tube-like structure formation of human umbilical vein endothelial cells (HUVECs). 4EGI-1 isomers suppress breast CSC tumorangiogenesis and tumor growth in vivo. In addition, 4EGI-1 decreases proliferation in and induces apoptosis into breast CSC tumor cells. Furthermore, 4EGI-1 selectively inhibits translation of mRNAs encoding NANOG, OCT4, CXCR4, c-MYC and VEGF in breast CSC tumors. Our study demonstrated that 4EGI-1 targets breast CSCs through selective inhibition of translation critical for breast CSCs, suggesting that selective translation initiation interference might be an avenue targeting CSCs within tumors.     

Ectopic Expression of miR-147 Inhibits Stem Cell Marker and Epithelial–Mesenchymal Transition (EMT)-Related Protein Expression in Colon Cancer Cells

Colon cancer is one of the most common cancers in the world. Epithelial-to-mesenchymal transition (EMT) is a crucial step in tumor progression and is also involved in the acquisition of stem cell-like properties. Some miRNAs have been shown to function as either tumor suppressors or oncogenes in colon cancer. Here we investigated the role of miR-147 in the regulation of the stem cell-like traits of colon cancer cells. We observed that miR-147 was downregulated in several colon cancer cell lines, and overexpressed miR-147 decreased the expression of cancer stem cell (CSC) markers OCT4, SOX2, and NANOG in the colon cancer cell lines HCT116 and SW480. Overexpressed miR-147 inhibited EMT by increasing the expression of epithelial markers E-cadherin and -catenin while decreasing the expression of mesenchymal markers fibronectin and vimentin. Moreover, activation of EMT by TGF- 1 treatment significantly counteracted the inhibitive effect of miR-147 on the expression of CSC markers OCT4, SOX2, and NANOG, supporting the idea that overexpressing miR-147 inhibited stem cell-like traits by suppressing EMT in colon cancer. In addition, we found that overexpressed miR-147 downregulated the expression of -catenin, c-myc, and survivin, which were related to the Wnt/ -catenin pathway. Moreover, treatment of miR-147 mimic-transfected cells with the Wnt/ -catenin pathway activator LiCl attenuated the inhibitive effect of the miR-147 mimic on the EMT and stem cell-like traits of colon cancer cells, indicating that ectopic expression of miR-147 inhibited stem cell-like traits in colon cancer cells by suppressing EMT via the Wnt/ -catenin pathway. In summary, our present study highlighted the crucial role of miR-147 in the inhibition of the stem cell-like traits of colon cancer cells and indicated that miR-147 could be a promising therapeutic target for colon cancer treatment.     

干细胞标志物在卵巢癌SKOV3细胞侧群细胞中的表达

目的：检测干细胞相关标志物在卵巢癌SKOV3细胞系侧群（side population,SP）细胞和非侧群（Non-SP）细胞中的表达差异,确定卵巢癌干细胞特异性标志物。 方法： Hoechst 33342染色检测SKOV3细胞中SP细胞的比例,流式细胞术检测SKOV3细胞的SP和Non-SP细胞中干细胞标志物CD133、CD117、CD44、ABCG2、ALDH1 的表达情况,荧光定量PCR检测SP和Non-SP细胞中 ABCG2、ALDH2、NANOG、OCT4、SOX2、CD133、CD117 mRNA的表达水平。 结果： SKOV3细胞中SP细胞比例为(1.56±0.35)%。 ALDH1、ABCG2在SP细胞中表达率分别为（87.3±5.76）%、（29.48±4.43）%,在Non-SP的表达率分别为（5.32±0.47）%、（3.01±1.69）%,差异有统计学意义（ P <0.01）;CD44在这两种细胞亚群中的表达率均高于99%（ P >005）;CD133、CD117在这两种细胞亚群中均不表达。 ALDH1、ABCG2、 NANOG、OCT4和SOX2 mRNA在SP细胞中的表达分别是Non-SP细胞的21.03倍（ P =0.001）、3.14倍（ P =0.001）、23.94倍（ P =0.001）、10.73倍（ P =0.009）和21.46倍( P =0001), CD133、CD117 mRNA在两种细胞亚群中均不表达。 结论： 人卵巢癌细胞株SKOV3中存在SP细胞亚群, ALDH1、ABCG2和NANOG、OCT4、SOX2 mRNA可能是卵巢癌干细胞标志物,为诊断及治疗卵巢癌提供了潜在的靶点。     

QKI impairs self-renewal and tumorigenicity of oral cancer cells via repression of SOX2

Cancer stem cells (CSCs) may contribute to tumor initiation, distant metastasis and chemo-resistance. One of RNA-binding proteins, Quaking (QKI), was reported to be a tumor suppressor. Here we showed that reduced QKI levels were observed in many human oral cancer samples. Moreover further reduction of QKI expression in CSCs was detected compared with non-CSCs in oral cancer cell lines. Overexpressing QKI in oral cancer cells significantly reduced CSC sphere formation and stem cell-associated genes. In tumor implanting nude mice model, QKI significantly impeded tumor initiation rates, tumor sizes and lung metastasis rates. As a contrast, knocking down QKI enhanced the above effects. Among the putative CSC target genes, SOX2 expression was negatively affected by QKI, mechanism study revealed that QKI may directly regulate SOX2 expression via specific binding with its 3′UTR in a cis element-dependent way. Loss of SOX2 even completely reversed the sphere forming ability in QKI knockdown cell line. Taken together, these data demonstrated that SOX2 is an important CSC regulator in oral cancer. QKI is a novel CSC inhibitor and impaired multiple oral CSC properties via partial repression of SOX2. Therefore, reduced expression of QKI may provide a novel diagnostic marker for oral cancer.     

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.     

SOX2在胰腺癌干细胞干性和化疗耐药中的作用及机制研究

[目的]探究性别决定相关基因簇2(SOX2)对胰腺癌干细胞干性与化疗耐药性的影响及影响机制。[方法]将培养至指数生长期胰腺癌干细胞随机分为SOX2抑制组、空白对照组与SOX2组,其中SOX2抑制组细胞与SOX2组细胞分别给予SOX2基因敲除与SOX2基因高表达处理,检测各组细胞SOX2 mRNA、八聚体结合转录因子4(OCT4)mRNA与谷胱甘肽过氧化物酶3(GPX3)mRNA表达水平;观察各组细胞增殖、侵袭及各组细胞对顺铂的耐药程度及在不同浓度顺铂处理下的凋亡情况。[结果] SOX2组细胞SOX2 mRNA与OCT4 mRNA表达水平明显高于SOX2抑制组与空白对照组细胞(P均=0.001);SOX2抑制组细胞增殖率与侵袭率明显低于空白对照组与SOX组(P<0.001);空白对照组细胞增殖率与侵袭率明显低于SOX2组(P<0.001);SOX2组细胞SOX2顺铂半数抑制浓度明显高于SOX2抑制组与空白对照组细胞(P<0.001);各浓度顺铂处理下的SOX2组细胞凋亡率均明显小于SOX2抑制组与空白对照组(P<0.001);SOX2组细胞GPX3 mRNA表达水平明显高于SOX2抑制组与空白对照组细胞(P<0.001)。[结论] SOX2能促进OCT4与GPX3表达,上调胰腺癌干细胞干性与化疗耐药性。     

Evaluation of the Effect of Orlistatorlistat on Expression of OCT4, Nanog,SOX2, and KLF4 Genes in Colorectal Cancer SW40 Cell Line

Background and Objective: Orlistat drug is one of the most criticalanti-obesity drugs that widely used around the world. The aim of this study was evaluation the effect of orlistat on the expression of OCT4, Nanog, SOX2, and KLF4 genes in the colorectal cancer SW40 cell line. Materials and Methods: SW40 cell line was cultured in DMEM medium contained orlistat for 24h, and cell viability was assessed by MTT assay. The fold changes of expression of OCT4, NANOG, KLF4, and SOX2 at mRNA level against β-actin were determined by real-timePCR. Two-sample t-test and one-way ANOVA were used to compare the mean of expression of different genes in different groups and different concentrations; a significant level of 0.05 was considered in all tests. Results: Our results showed a significant difference in cell viability, when different doses of Orlistat were used for 24 hour. concentrations of 25 and 100 μM reduce significantly the expression of OCT4 (p <0.05) and SOX2 (p <0.05) in the treated group in comparison to control (p <0.05). Also, the mRNA expression of KLF4 and Nanog was reduced significantly after treatment of SW40 cell lines was performed with 100 μM doses of Orlistat (p <0.05). Conclusion: It appears that after further studies in animal and human phases, orlistat can be used for the treatment of Colorectal Cancer.     

Prognostication of OCT4 isoform expression in prostate cancer

Cancer stem cells (CSCs) refer to a subset of tumor cells that self-renew and affect tumor heterogeneity. This model has attracted considerable interest in recent years due to its implications in the prognosis and clinical management of cancer because CSCs mediate the occurrence, growth, and recurrence of tumors. OCT4 is central to embryonic stem cell self-renewal and differentiation into specific lineages and encodes two chief isoforms that are generated by alternative splicing—OCT4A and OCT4B. Their function in prostate cancer (PCa) is unknown. The prognostic function of OCT4 isoforms in PCa samples was examined by immunohistochemistry (IHC) and sensitivity and specificity of the antibodies used were evaluated by molecular biology techniques. Biochemical and pathological data and specimens from 193 patients with PCa were evaluated retrospectively. IHC, western blot, immunofluorescence, and automated image analysis were also performed. IHC was performed on a tissue microarray, and western blot and immunofluorescence were performed using the PCa cell line DU-145. IHC expression of OCT4 isoforms correlated with biochemical and pathological parameters, particularly biochemical recurrence-free survival (BCRFS). Patients with higher levels of OCT4B had lower Gleason scores and decreased likelihood of experiencing biochemical recurrence (BR). OCT4A⁺ OCT4B^? patients had the shortest BCRFS, and positivity for OCT4B expression was an independent prognostic factor for BCRFS in the multivariate analysis. We conclude that the expression of OCT4B is a strong marker of good prognosis, and its presence is associated with a decreased likelihood of BR. Thus, OCT4B might represent a powerful clinical prognostic biomarker for PCa patients.     

Prognostic significance of NANOG and KLF4 for breast cancer

Background

Some of the induced pluripotent stem cell (iPS cell)-inducing factors have been reported to be expressed in breast cancer. The aim of the present study was to examine the relationship between the expression of iPS cell-inducing factors and the prognosis of breast cancer patients.

Methods

In 100 breast cancer patients, the expression of c-MYC, KLF4, NANOG, OCT4, and SOX2 was determined by immunohistochemistry using a tissue microarray analysis.

Results

Patients with strong expression of NANOG had significantly lower disease-free survival (DFS) and overall survival rates than those with weak expression of NANOG (P = 0.004 and 0.033, respectively). In contrast, patients with strong expression of KLF4 had better DFS (P = 0.014).

Conclusions

Strong expression of NANOG is an indicator of a poor prognosis for breast cancer patients, whereas KLF4 is a favorable prognostic indicator. Our results suggest that NANOG stimulates the growth and metastasis of breast cancer cells, whereas KLF4 inhibits these processes.     

The SOX17/miR-371-5p/SOX2 axis inhibits EMT,stem cell properties and metastasis in colorectal cancer

Cancer stem cells (CSCs) and EMT-type cells, which share molecular characteristics with CSCs, have been believed to play critical roles in tumor metastasis. Although much progress has been garnered in elucidating the molecular pathways that trigger EMT, stemness and metastasis, a number of key mechanistic gaps remain elusive. In the study, miR-371-5p was obviously down-regulated in primary CRC tissues compared with matched adjacent normal mucosa and correlated significantly with differentiation, tumor size, lymphatic and liver metastases. MiR-371-5p could attenuate proliferation, invasion in vitro and metastasis in vivo in CRC cells. It also suppressed EMT by regulating Wnt/β-catenin signaling and strongly decreased the CRC stemness phenotypes. Moreover, demethylation of SOX17 induced miR-371-5p expression and consequently suppressed its direct target SOX2 in CRC cells. MiR-371-5p was necessary for SOX17 mediated cancer-related traits and SOX2 was a functional target of miR-371-5p. A positive relationship between SOX17 and miR-371-5p expression and a negative one between miR-371-5p and SOX2 expression were observed in CRC cell lines and tissues. In conclusion, we identified miR-371-5p as an important “oncosuppressor” in CRC progression and elucidated a novel mechanism of the SOX17/miR-371-5p/SOX2 axis in the regulation of EMT, stemness and metastasis, which may be a potential therapeutic target.