Inhibition of breast cancer growth via miR-7 suppressing ALDH1A3 activity concomitant with decreasing breast cancer stem cell subpopulation

Breast cancer patients with high expression of aldehyde dehydrogenases (ALDHs) cell population have higher tolerability to chemotherapy since the cells posses a characteristic of breast cancer stem cells (BCSCs) that are resistant to conventional chemotherapy. In this study, we found that the ALDH-positive cells were higher in CD44⁺CD24⁻ and CD44⁺CD24⁻ESA⁺BCSCs than that in both BT549 and MDA-MB-231 cell lines but microRNA-7 (miR-7) level was lower in CD44⁺CD24⁻ and CD44⁺CD24⁻ESA⁺BCSCs than that in MDA-MB-231 cells. Moreover, miR-7 overexpression in MDA-MB-231 cells decreased ALDH1A3 activity by miR-7 directly binding to the 3′-untranslated region of ALDH1A3; while the ALDH1A3 expression was downregulated in MDA-MB-231 cells, the expressions of CD44 and Epithelium Specific Antigen (ESA) were reduced along with decreasing the BCSC subpopulation. Significantly, enforced expression of miR-7 in CD44⁺CD24⁻ESA⁺BCSC markedly inhibited the BCSC-driven xenograft growth in mice by decreasing an expression of ALDH1A3. Collectively, the findings demonstrate the miR-7 inhibits breast cancer growth via suppressing ALDH1A3 activity concomitant with decreasing BCSC subpopulation. This approach may be considered for an investigation on clinical treatment of breast cancers.     

ALDH adenoid cystic carcinoma cells display cancer stem cell properties and are responsible for mediating metastasis

The cancer stem cell (CSC) theory has been proposed to explain the tumor heterogeneity and carcinogenesis process. Recent studies indicate that aldehyde dehydrogenase (ALDH) activity represents a promising CSC marker. Here, we aimed to determine whether human adenoid cystic carcinoma (AdCC) also follows CSC model by exploring the CSC properties of AdCC cells expressing high level of ALDH activity. Utilizing in-vivo series transplantation assays, we found ALDH^high AdCC cells were capable of self-renewal and of generating tumors that recapitulate the heterogeneity of the parental tumor. Utilizing in-vitro assay, we found only ALDH^high AdCC cells have tumorsphere-forming ability in anchorage-independent cultures. Finally, we showed ALDH^high AdCC cells possess highly invasive capability and are responsible for mediating metastasis. These findings suggest the existence of a developmental hierarchy within human AdCC and further elucidation of the unique survival mechanism of AdCC derived CSC population may provide novel therapeutic strategies to treat AdCC.     

肿瘤干细胞及其耐药机制

肿瘤干细胞是存在于造血系统肿瘤和一些实体瘤中具有干细胞特性的细胞。肿瘤干细胞假说认为,经药物治疗后肿瘤复发和转移与肿瘤干细胞残存有密切关系。其原因可能是肿瘤干细胞高表达ABC转运蛋白和Bcl-2抗凋亡蛋白,同时其本身又具有一些干细胞特性。对肿瘤干细胞耐药机制的研究,将有助于发现新的肿瘤治疗靶点和更好的抗癌策略。     

ALDH1蛋白表达与胶质瘤干细胞体外分化相关性的研究

目的探讨乙醛脱氢酶1（ALDH1）蛋白表达与胶质瘤干细胞体外分化相关性。 方法将原代培养的胶质瘤干细胞分为分化组与对照组,分化组细胞使用10%的胎牛血清诱导,对照组细胞继续在无血清环境中培养,通过免疫荧光细胞化学染色和Western blot观察两组细胞ALDH1蛋白的表达情况,分别使用Wilcoxon符号秩检验和配对样本t检验分析两组ALDH1阳性细胞率和相对蛋白含量的差异。 结果分化组细胞呈完全贴壁生长,异型性明显,对照组细胞呈团状聚集,形态较为均一。两组的ALDH1阳性细胞率分别为：分化组18.78%?±?6.03%,对照组81.23%±?3.19%;ALDH1相对蛋白含量分别为：分化组0.035±0.009,对照组0.390±0.108。两组的阳性细胞率和相对蛋白含量比较差异具有统计学意义（Z = -2.666,P = 0.008;t = -10.637,P = 0.000）。 结论本实验通过半定量研究进一步证实了在体外培养状态下,ALDH1主要存在于较为原始的肿瘤细胞中,分化后几乎不表达,提示ALDH1作为可能的胶质瘤干细胞标志物仍有进一步研究的价值。     

Aldehyde dehydrogenase activity selects for the holoclone phenotype in prostate cancer cells

Aldehyde dehydrogenase 1 (ALDH) activity is considered to be a marker of cancer stem cells (CSCs) in many tumour models, since these cells are more proliferative and tumourigenic than ALDH^Lo cells in experimental models. However it is unclear whether all CSC-like cells are within the ALDH^Hi population, or whether all ALDH^Hi cells are highly proliferative and tumourigenic. The ability to establish a stem cell hierarchy in vitro, whereby sub-populations of cells have differing proliferative and differentiation capacities, is an alternate indication of the presence of stem cell-like populations within cell lines. In this study, we have examined the interaction between ALDH status and the ability to establish a stem cell hierarchy in PC3 prostate cancer cells. We demonstrate that PC3 cells contain a stem cell hierarchy, and isolation of ALDH^Hi cells enriches for the most primitive holoclone population, however holoclone formation is not restricted to ALDH^Hi cells. In addition, we show that ALDH activity undergoes phenotypic plasticity, since the ALDH^Lo population can develop ALDH^Hi populations comparable to parental cells within 2 weeks in culture. Furthermore, we show that the majority of ALDH^Hi cells are found within the least primitive paraclone population, which is circumvented by culturing PC3 cells as spheroids in defined medium favouring stem cell characteristics. Although ALDH^Hi status enriches for holoclone formation, this activity may be mediated by a minority of ALDH^Hi cells.     

Aldehyde dehydrogenase 1 is a putative marker for cancer stem cells in head and neck squamous cancer

Aldehyde dehydrogenase 1 (ALDH1) has been considered to be a marker for cancer stem cells. However, the role of ALDH1 in head and neck squamous cell carcinoma (HNSCC) has yet to be determined. In this study, we isolated ALDH1-positive cells from HNSCC patients and showed that these HNSCC-ALDH1⁺ cells displayed radioresistance and represented a reservoir for generating tumors. Based on microarray findings, the results of Western blotting and immunofluorescent assays further confirmed that ALDH1⁺-lineage cells showed evidence of having epithelial-mesenchymal transition (EMT) shifting and endogenously co-expressed Snail. Furthermore, the knockdown of Snail expression significantly decreased the expression of ALDH1, inhibited cancer stem-like properties, and blocked the tumorigenic abilities of CD44⁺CD24⁻ALDH1⁺ cells. Finally, in a xenotransplanted tumorigenicity study, we confirmed that the treatment effect of chemoradiotherapy for ALDH1⁺ could be improved by Snail siRNA. In summary, it is likely that ALDH1 is a specific marker for the cancer stem-like cells of HNSCC.     

A proteomic kinetic analysis of IGROV1 ovarian carcinoma cell line response to cisplatin treatment

Ovarian cancer is one of the leading causes of mortality by gynecological cancer. Despite good response to surgery and initial chemotherapy, essentially based on cisplatin (cis-diamino-dichloro-platinum(II) (CDDP)) compounds, frequent recurrences with chemoresistance acquisition are responsible for poor prognosis. Several mechanisms have been described as implicated in CDDP resistance, however they are not sufficient to exhaustively account for this resistance emergence. We applied a proteomic approach based on 2-DE coupled with MS (MALDI-TOF/TOF) to identify proteins associated with chemoresistance induced by CDDP. A kinetic analysis of IGROV1 cell behavior following treatment with CDDP and subsequent statistical analysis revealed time and/or concentration-dependent modifications in protein expression. We evidenced events such as decreased amino-acid and nucleotide synthesis potentially associated with cell cycle blockade, and variations that may be related to resistance acquisition, such as possible enhanced glycolysis and increased proliferating potential. Moreover, overexpressions of aldehyde dehydrogenase 1 and both cytokeratins 8 and 18 were consistent with our previous findings, demonstrating that expression of these proteins was increased in cisplatin-resistant IGROV1-R10 as compared to IGROV1 parental cells. Identification of such proteins could allow improved understanding of the mechanisms leading to cell death or survival and, thus, to the acquisition of chemoresistance.     

Presence and role of stem cells in ovarian cancer

Ovarian cancer is the deadliest gynecological malignancy. It is typically diagnosed at advanced stages of the disease, with metastatic sites disseminated widely within the abdominal cavity. Ovarian cancer treatment is challenging due to high disease recurrence and further complicated pursuant to acquired chemoresistance. Cancer stem cell(CSC) theory proposes that both tumor development and progression are driven by undifferentiated stem cells capable of self-renewal and tumor-initiation. The most recent evidence revealed that CSCs in terms of ovarian cancer are not only responsible for primary tumor growth, metastasis and relapse of disease, but also for the development of chemoresistance. As the elimination of this cell population is critical for increasing treatment success, a deeper understanding of ovarian CSCs pathobiology, including epithelial-mesenchymal transition, signaling pathways and tumor microenvironment, is needed. Finally, before introducing new therapeutic agents for ovarian cancer, targeting CSCs, accurate identification of different ovarian stem cell subpopulations, including the very small embryoniclike stem cells suggested as progenitors, is necessary. To these ends, reliable markers of ovarian CSCs should be identified. In this review, we present the current knowledge and a critical discussion concerning ovarian CSCs and their clinical role.     

Inhibition of PARP1 activity enhances chemotherapeutic efficiency in cisplatin-resistant gastric cancer cells

Cisplatin (DDP) is the first line chemotherapeutic drug for several cancers, including gastric cancer (GC). Unfortunately, the rapid development of drug resistance remains a significant challenge for the clinical application of cisplatin. There is an urgent need to develop new strategies to overcome DDP resistance for cancer treatment. In this study, four types of human GC cells have been divided into naturally sensitive or naturally resistant categories according to their responses to cisplatin. PARP1 activity (poly (ADP-ribose), PAR) was found to be greatly increased in cisplatin-resistant GC cells. PARP1 inhibitors significantly enhanced cisplatin-induced DNA damage and apoptosis in the resistant GC cells via the inhibition of PAR. Mechanistically, PARP1 inhibitors suppress DNA-PKcs stability and reduce the capability of DNA double-strand break (DSB) repair via the NHEJ pathway. This was also verified in BGC823/DDP GC cells with acquired cisplatin resistance. In conclusion, we identified that PARP1 is a useful interceptive target in cisplatin-resistant GC cells. Our data provide a promising therapeutic strategy against cisplatin resistance in GC cells that has potential translational significance.     

Role of the Akt/mTOR survival pathway in cisplatin resistance in ovarian cancer cells

The mechanism of cisplatin resistance in cancer cells is not fully understood. Here, we show that the Akt/mTOR survival pathway plays an important role in cisplatin resistance in human ovarian cancer cells. Specifically, we found that cisplatin treatment activates the Akt/mTOR survival pathway and that inhibition of this pathway by the PI3 K inhibitor LY294002 or knockdown of Akt sensitizes ovarian cancer cells to cisplatin. Furthermore, we generated cisplatin-resistant cells and found that resistant cells express a higher level of activated Akt as compared to their cisplatin sensitive counterparts. Importantly, inhibition of Akt or mTOR sensitized resistant cells to cisplatin-induced apoptosis. Taken together, our data indicate that activation of the Akt/mTOR pathway prevents cisplatin-induced apoptosis, leading to cisplatin resistance. Therefore, our study suggests that cisplatin resistance can be overcome by targeting the Akt/mTOR survival pathway in human ovarian cancer cells.     

The expression levels of the translational factors eEF1A 1/2 correlate with cell growth but not apoptosis in hepatocellular carcinoma cell lines with different differentiation grade

Despite the involvement of the elongation factors eEF1A (eEF1A1 and eEF1A2) in the development of different cancers no information is available on their possible contribution to the biology of hepatocellular carcinoma (HCC). We investigated the expression of both forms of eEF1A in HepG2 and JHH6 cell lines considered to be a good in vitro model of HCC at different stage of differentiation. Our data indicate that the mRNA amount of eEF1A1 is increased in both cell lines as compared to normal liver tissue, but eEF1A2 mRNA level is markedly increased only in JHH6. Moreover, the less differentiated cell line JHH6 displays higher EEF1A1 and EEF1A2 mRNAs levels and an higher nuclear-enriched/cytoplasm ratio of EEF1A protein compared to the better differentiated HepG2 cell line. Over-expression depends only partially on gene amplification. The more abundant mRNA levels and the higher nuclear-enriched/cytoplasm ratio of eEF1A in JHH6 neither correlate with apoptosis resistance nor with proliferation rate in sub-confluent cells. However, in confluent cells, a clear tendency to maintain JHH6 into the cell cycle was observed. In conclusion, we document the increased mRNA levels of EEF1A genes in HCC cell lines compared to normal liver. Additionally, we show the increased nuclear-enriched/cytoplasmic protein ratio of eEF1A and the marked raise of the expression of both eEF1A forms in JHH6 compared to HepG2, suggesting the possibility that eEF1A forms might become a relevant markers related to HCC tumor phenotype.     

KDM2A对人卵巢癌顺铂耐药细胞株A2780增殖和凋亡的影响及机制研究

目的:探讨赖氨酸脱甲基酶2A(Lysine-specific demethylase 2A,KDM2A)对顺铂(cisplatin,DDP)耐药的人卵巢癌细胞A2780细胞增殖和凋亡的影响及其可能作用机制。方法:通过构建慢病毒载体转染A2780/DDP,分为A2780、A2780/DDP、A2780/DDP/KDM2A(转染KDM2A)、A2780/DDP/Jagged1(转染Jagged1)以及A2780/DDP/NC(转染病毒载体)组。采用Western blot检测3组KDM2A、Jagged1、Bcl2和BAX蛋白表达,CCK8和平板克隆形成实验检测细胞对顺铂的敏感性,流式细胞术检测细胞凋亡情况。结果:A2780/DDP细胞KDM2A和Jagged1的蛋白表达水平均显著高于A2780细胞(P0.05),且A2780/DDP/KDM2A细胞中KDM2A和Jagged1的蛋白表达均低于A2780/DDP以及阴性对照组A2780/DDP/NC(P0.05);A2780/DDP/Jagged1细胞的Jagged1蛋白表达低于A2780/DDP以及A2780/DDP/NC(P0.05),而其KDM2A蛋白的表达比较差异无统计学意义(P0.05)。不同浓度DDP处理的A2780/DDP/KDM2A细胞的生长抑制率均显著高于A2780/DDP/NC和A2780/DDP细胞(P0.05),A2780/DDP/KDM2A细胞克隆形成数量亦明显高于A2780/DDP/NC和A2780/DDP细胞(P0.05)。A2780/DDP/KDM2A细胞凋亡率为(25.84±3.27)%,明显高于A2780/DDP细胞[(14.29±1.96)%](P0.05)和A2780/DDP/NC细胞[(12.46±2.15)%](P0.05)。A2780/DDP/KDM2A细胞中Bcl-2蛋白表达明显低于A2780/DDP细胞(P0.05),而A2780/DDP/KDM2A细胞Bax的表达水平却高于A2780/DDP细胞(P0.05)。结论:KDM2A可能通过上调Jagged1的表达,促进人卵巢癌细胞A2780的增殖并抑制其凋亡,进而降低人卵巢癌耐药细胞A2780的顺铂敏感性。     

HE4、ALDH1、CD44在卵巢良恶性肿瘤鉴别诊断中的检测效能观察

摘要 目的：观察人附睾蛋白4（HE4）、乙醛脱氢酶1（ALDH1）、黏附分子CD44在卵巢良恶性肿瘤鉴别诊断中的检测效能。方法：选取2020年1月~2022年5月我院收治的100例卵巢癌患者、100例卵巢良性肿瘤患者,分为纳入恶性组与良性组,另外选取同期体检的100例健康女性作为对照组。比较三组患者血清中HE4、ALDH1及组织中CD44的表达情况,并采用受试者工作特征（ROC）曲线分析其对卵巢良恶性肿瘤的鉴别诊断价值。结果：恶性组患者的HE4、ALDH1水平及CD44阳性表达率均高于良性组与对照组（P＜0.05）,良性组患者的HE4、ALDH1水平及CD44阳性表达率高于对照组（P＜0.05）。与临床分期为Ⅰ~Ⅱ期、未发生淋巴转移患者比较,临床分期为Ⅲ~Ⅳ期、发生淋巴转移的卵巢癌患者HE4、ALDH1水平及CD44阳性表达率更高（P＜0.05）,Spesrman相关性分析结果显示,HE4、ALDH1水平及CD44阳性表达率均与卵巢癌患者临床分期、淋巴转移成正相关（P＜0.05）。ROC特征曲线结果显示,HE4、ALDH1、CD44鉴别卵巢良恶性肿瘤的曲线下面积（AUC）分别为0.837、0.768及0.610,采用3项指标联合（并联）鉴别卵巢良恶性肿瘤的AUC及敏感度均高于单一指标诊断（P＜0.05）。结论：卵巢恶性肿瘤患者血清中HE4、ALDH1及组织中CD44均呈现高表达,且表达水平与卵巢癌患者临床分期、淋巴转移密切相关,HE4、ALDH1联合CD44检测对卵巢良恶性肿瘤具有较高的的鉴别诊断价值。     

Ion channels and transporters in the development of drug resistance in cancer cells

Multi-drug resistance (MDR) to chemotherapy is the major challenge in the treatment of cancer. MDR can develop by numerous mechanisms including decreased drug uptake, increased drug efflux and the failure to undergo drug-induced apoptosis. Evasion of drug-induced apoptosis through modulation of ion transporters is the main focus of this paper and we demonstrate how pro-apoptotic ion channels are downregulated, while anti-apoptotic ion transporters are upregulated in MDR. We also discuss whether upregulation of ion transport proteins that are important for proliferation contribute to MDR. Finally, we discuss the possibility that the development of MDR involves sequential and localized upregulation of ion channels involved in proliferation and migration and a concomitant global and persistent downregulation of ion channels involved in apoptosis.