Ovarian cancer stem cell: A potential therapeutic target for overcoming multidrug resistance

The cancer stem cell (CSC) model encompasses an advantageous paradigm that in recent decades provides a better elucidation for many important biological aspects of cancer initiation, progression, metastasis, and, more important, development of multidrug resistance (MDR). Such several other hematological malignancies and solid tumors and the identification and isolation of ovarian cancer stem cells (OV-CSCs) show that ovarian cancer also follows this hierarchical model. Gaining a better insight into CSC-mediated resistance holds promise for improving current ovarian cancer therapies and prolonging the survival of recurrent ovarian cancer patients in the future. Therefore, in this review, we will discuss some important mechanisms by which CSCs can escape chemotherapy, and then review the recent and growing body of evidence that supports the contribution of CSCs to MDR in ovarian cancer.     

曲古霉素A诱导人膀胱癌细胞周期阻滞和凋亡的研究

目的:探讨组蛋白去乙酰化酶抑制剂曲古霉素A(TSA)对人膀胱癌T24细胞周期和凋亡的影响。方法:以不同剂量TSA(0.1μM,0.3μM和1μM)处理T24细胞。采用MTT法检测细胞存活率,AnnexinV-PI染色检测细胞凋亡,流式细胞仪检测caspase-3活性,Western blot法检测P21蛋白表达。结果:TSA剂量依赖性降低膀胱癌细胞存活率,促进细胞凋亡,表现为AnnexinV阳性细胞明显增多,同时活化的caspase-3水平增高。TSA还可通过诱导膀胱癌细胞周期阻滞于G2/M期抑制细胞生长,且呈剂量依赖性。结论:TSA通过促进caspase-3激活诱导膀胱癌细胞凋亡,同时诱导细胞阻滞于G2/M期。     

Ovarian cancer is associated with changes in glycosylation in both acute-phase proteins and IgG

Ovarian cancer is the fourth most common cancer in women in the Western world. In a pilot scale study, we highlight changes in the total serum glycome of patients with advanced ovarian cancer that might shed insight into disease pathogenesis. These changes include increases in levels of core fucosylated, agalactosyl biantennary glycans (FA2) and sialyl Lewis x (SLe(x)). To investigate further which proteins contribute to these alterations, we developed technology to analyze simultaneously the glycosylation of protein glycoforms contained in single spots excised from a 2D gel (<1 ng protein). The acute-phase proteins, haptoglobin, alpha1-acid glycoprotein, and alpha1-antichymotrypsin from patients contained elevated levels of subsets of glycoforms containing SLe(x). We also established that IgG heavy chains from patients contained twice the level of FA2 compared with healthy controls. Serum CA125 is the only biomarker that is used routinely, and there is a need for complementary markers that will improve both sensitivity and specificity. There was some preliminary indication that combinations of changes in the serum glycome might improve the separation of ovarian cancer and benign tumors; however, a larger study using data receiver operating characteristic curves will be required to draw any firm conclusions.     

Proteomics profile changes in cisplatin-treated human ovarian cancer cell strain

To compare the alterations in proteomes between cisplatin-treated and -untreated human ovarian cancer SKOV3 cells, and to explore the feasibility of proteomics in research about antitumor mechanisms of agents, SKOV3 cells were exposed to cisplatin (6 ώg/mL) for 6 h. Then, the cells were collected and solubilized and global proteins were extracted by lysis buffer; two-dimensional electrophoresis was conducted with the IPG readystrips as carriers; the gels were stained with Coomassie blue and alterations between gels were compared by PDQuest. Eventually, 11 spots with significant differences were selected and excised and the proteins were identified by PMF and MS/MS analysis. The results revealed that exposure to cisplatin could notably increase expressions of some proteins, such as tropomyosin family, actin family, triosephosphate isomerase family, and HSP60, etc.; while expressions of some other proteins decreased, such as enolase family, etc. Those proteins were involved in cellular energy metabolism, transformation, apoptosis and morphologic maintenance, which suggested that alterations of those physiological processes might be involved in anti-tumor mechanism of cisplatin.     

Proteomics profile changes in cisplatin-treated human ovarian cancer cell strain

Ovarian cancer is an important gynecological tumor, with the third highest morbidity rate and highest mor-tality rate in gynecological cancers, of which the 5-year survival rate remains at only 19%―38.7%[1]. Tumors occurring in ovary can hardly be diagnosed in the early stages for the dormant start, and approxi-mately 70% patients cannot get the final diagnosis until the advanced stages. Surgical operation and post-operational chemotherapy based on cisplatin have become the primary treatment …     

Targeting stromal cell sialylation reverses T cell-mediated immunosuppression in the tumor microenvironment

1. Download : Download high-res image (271KB)
2. Download : Download full-size image

     

Advances in ovarian cancer screening: health and medicine for women: a multidisciplinary, evidence-based review of mid-life health concerns

Early detection is imperative for improving survival from ovarian cancer, the leading cause of death from gynecological cancer in the United States. At the Health and Medicine for Women continuing medical education (CME) conference at Yale in September 2010, Dr. Gil Mor, a researcher in the Department of OB/GYN at Yale, presented recent advances on the pathophysiology of ovarian cancer. These advances, and particularly our growing understanding of cancer stem cells, may help overcome the limitations of current ovarian cancer detection and treatment methods.     

Effect of essential fatty acids on circulating T cell subsets in patients with colorectal cancer

The effect of essential fatty acids (EFA), given orally as dietary supplements, on the responsiveness in vitro of peripheral blood lymphocytes (PBL), to the mitogen concanavalin A have been studied in 10 patients with localized and 14 patients with advanced colorectal cancer. The degree of lymphocyte activation was assessed by measuring the amount of tritiated [³H]thymidine incorporated into newly synthesised lymphocyte DNA. The results were expressed as stimulation indices. T cell responses to concanavalin A stimulation showed a significant reduction of stimulation indices following EFA supplementation, in both the localized (P=0.026) and advanced (P=0.016) tumour groups, when compared with pretreatment activity in vitro. Mixing experiments, using EFA-supplemented and non-EFA-supplemented lymphocytes with concanavalin A, suggest no enhancement of T suppressor cell activity. Cell surface marker analysis (fluorescence-activated cell sorting for CD phenotyping) revealed a reduction of absolute numbers of CD4⁺ and CD8⁺ lymphocytes following EFA supplementation. The stimulation indices returned to presupplementation values 3 months following cessation of EFA intake. There was no significant change of these indices in the control (no EFA supplementation) advanced tumour group tested. This study suggests that EFA supplementation in patients with colorectal cancer selectively reduces circulating PBL. and T cell subset (including suppressor cells) numbers and/or activity. Such effects may have an important outcome in patients with malignant disease.This work was supported by grants from the Grampian Health Broad, the Royal College of Surgeons of Edinburgh, and Scottish Hospital Endownment Research Trust     

New insights into CD4+ T cell abnormalities in systemic sclerosis

Systemic sclerosis (SSc) is an autoimmune connective tissue disease that is characterized by vasculopathy and excessive deposition of extracellular matrix, which causes fibrosis of the skin and internal organs and eventually leads to multiorgan dysfunction. Studies have shown that CD4⁺ T cell activation is a key factor in the pathogenesis of scleroderma because activated T cells can release various cytokines, resulting in inflammation, microvascular damage and fibrosis. T helper cell 17 (Th17) and regulatory T (Treg) cell activities are a hallmark SSc, as Th17-type cytokines can induce both inflammation and fibrosis. More recently, several studies have reported new T cell subsets, including Th9 and Th22 cells, along with their respective cytokines in the peripheral blood, serum and skin lesions of individuals with SSc. Herein, we review recent data on various CD4⁺ T helper cell subsets in SSc, and discuss potential roles of these cells in promoting inflammation and fibrosis.     

Anti-oncogenic PTEN induces ovarian cancer cell senescence by targeting P21

Deletion and mutation of phosphatase and tensin homolog deleted on chromosome10 (PTEN) are closely associated with the occurrence of tumors. Tumor suppressor gene PTEN mutation plays an important role in the pathogenesis of ovarian cancer. However, it has been unclear whether it can regulate the senescence of ovarian cancer cells. We speculated that PTEN might inhibit the occurrence and development of ovarian cancer by promoting the expression of P21. We found that the expression of TRIM39 in human ovarian cancer was significantly diminished. In SKOV3 cells treated with naringin, the expression of TRIM39, which binds P21 and inhibits P21 degradation, was significantly elevated. Real-time polymerase chain reaction (PCR), Western blot, and immunofluorescence were used to detected the expression of PTEN, p21, and TRIM39, β-galactosidase Staining was used to detect cell senescence, Ki67 staining was used to observe cell proliferation, Trim39 interference or overexpression assay was used to detect its function. We speculated that PTEN might promote SKOV3 cell senescence by increasing TRIM39 expression and decreasing P21 degradation. Furthermore, by interfering with TRIM39 in SKOV3 cells, we found that the expression of P21 was downregulated, and the number of senescent SKOV3 cells decreased. With overexpression of TRIM39 in SKOV3 cells, the expression of P21 was upregulated, and the number of senescent SKOV3 cells increased. When naringin, a PTEN agonist, was added to SKOV3 cells in which TRIM39 protein was interfered with, the expression of P21 was significantly lower than that in the control group, and the number of senescent ovarian cancer cells was significantly diminished. Our results indicated that PTEN maintained the stability of P21 and decreased the degradation of P21 by increasing TRIM39 expression, thus promoting the senescence of SKOV3 cells, and PTEN maintained the stability of p21 and promoted the aging of SKOV3 cells might be a novel therapeutic target for ovarian cancer.     

Dynamic and adaptive cancer stem cell population admixture in colorectal neoplasia

1. Download : Download high-res image (197KB)
2. Download : Download full-size image

     

Using ABCG2-molecule-expressing side population cells to identify cancer stem-like cells in a human ovarian cell line

CSCs (cancer stem cells) are a small subset of cells within a tumour that possesses the characteristics of stem cells and are considered to be responsible for resistance to chemoradiation. Identification of CSCs through stem cell characteristics might have relevant clinical implications. In this study, SP (side population ) cells were sorted from a human ovarian cancer cell line by FACS to determine whether cancer stem cell-like SP cells were present. A very small fraction of SP cells (2.6%) was detected in A2780 cells. SP cells possessed the following characteristics: highly proliferative activity, marked ability for self-renewal in soft agar and culture medium, high expression of ABCG2, drug resistance to vinblastine in vitro, and strong tumourigenic potential in Balb/c nude mice. It is concluded that there exists in the A2780 cell line a small number of SP cells with high expression of ABCG2. The cells have the characteristics of cancer stem-like cells, and identification and cloning of such human SP cells can help in improving therapeutic approaches to ovarian cancer in patients.     

Microenvironment mesenchymal cells protect ovarian cancer cell lines from apoptosis by inhibiting XIAP inactivation

Epithelial ovarian carcinoma is characterized by high frequency of recurrence (70% of patients) and carboplatin resistance acquisition. Carcinoma-associated mesenchymal stem cells (CA-MSC) have been shown to induce ovarian cancer chemoresistance through trogocytosis. Here we examined CA-MSC properties to protect ovarian cancer cells from carboplatin-induced apoptosis. Apoptosis was determined by Propidium Iodide and Annexin-V-FITC labelling and poly-ADP-ribose polymerase cleavage analysis. We showed a significant increase of inhibitory concentration 50 and a 30% decrease of carboplatin-induced apoptosis in ovarian cancer cells incubated in the presence of CA-MSC-conditioned medium (CM). A molecular analysis of apoptosis signalling pathway in response to carboplatin revealed that the presence of CA-MSC CM induced a 30% decrease of effector caspases-3 and -7 activation and proteolysis activity. CA-MSC secretions promoted Akt and X-linked inhibitor of apoptosis protein (XIAP; caspase inhibitor from inhibitor of apoptosis protein (IAP) family) phosphorylation. XIAP depletion by siRNA strategy permitted to restore apoptosis in ovarian cancer cells stimulated by CA-MSC CM. The factors secreted by CA-MSC are able to confer chemoresistance to carboplatin in ovarian cancer cells through the inhibition of effector caspases activation and apoptosis blockade. Activation of the phosphatidylinositol 3-kinase (PI3K)/Akt signalling pathway and the phosphorylation of its downstream target XIAP underlined the implication of this signalling pathway in ovarian cancer chemoresistance. This study reveals the potentialities of targeting XIAP in ovarian cancer therapy.     

TLR4-dependent effects of ISAg treatment on conventional T cell polarization in vivo

We recently demonstrated that the polysaccharide component of the Korean medicinal herb Angelica gigas (immuno-stimulatory fraction of A. gigas; ISAg) induces anticancer effects in mice by activating natural killer (NK) and natural killer T (NKT) cells. However, it is unclear whether the use of ISAg in vivo can affect the differentiation of conventional T cells. Here, we investigated the effects of ISAg on the activation of conventional CD4⁺ and CD8⁺ T cells. We found that the administration of ISAg induced the polarization of CD4⁺ T cells toward the acquisition of the Th1 phenotype in vivo. Additionally, in mice treated with ISAg, CD8⁺ T cells produced more IFNγ than in control mice treated with PBS. Moreover, treatment with ISAg activated CD4⁺ and CD8⁺ T cells as well as NK and NKT cells, resulting in the secretion of Th1-type cytokines in a toll-like receptor 4 (TLR4)-dependent manner, implying that TLR4 is critical for an optimal Th1 response. Interestingly, ISAg treatment increased the number of Foxp3⁺ Treg cells, but not of Th2 cells, compared to control mice treated with PBS, indicating that ISAg possesses an immunomodulatory capacity that can control adaptive immune responses. Taken together, our results indicate that ISAg possesses a Th1-enhancing activity that could be used to treat Th2-mediated allergic immune diseases such as atopic dermatitis.     

L-asparaginase inhibits invasive and angiogenic activity and induces autophagy in ovarian cancer

Recent work identified L‐asparaginase (L‐ASP) as a putative therapeutic target for ovarian cancer. We suggest that L‐ASP, a dysregulator of glycosylation, would interrupt the local microenvironment, affecting the ovarian cancer cell—endothelial cell interaction and thus angiogenesis without cytotoxic effects. Ovarian cancer cell lines and human microvascular endothelial cells (HMVEC) were exposed to L‐ASP at physiologically attainable concentrations and subjected to analyses of endothelial tube formation, invasion, adhesion and the assessment of sialylated proteins involved in matrix‐associated and heterotypic cell adhesion. Marked reduction in HMVEC tube formation in vitro, HMVEC and ovarian cancer cell invasion, and heterotypic cell‐cell and cell‐matrix adhesion was observed (P < 0.05–0.0001). These effects were associated with reduced binding to ß1integrin, activation of FAK, and cell surface sialyl Lewis^X (sLe^x) expression. No reduction in HMVEC E‐selectin expression was seen consistent with the unidirectional inhibitory actions observed. L‐ASP concentrations were non‐toxic to either ovarian cancer or HMVEC lines in the time frame of the assays. However, early changes of autophagy were observed in both cell types with induction of ATG12, beclin‐1, and cleavage of LC‐3, indicating cell injury did occur. These data and the known mechanism of action of L‐ASP on glycosylation of nascent proteins suggest that L‐ASP reduces of ovarian cancer dissemination and progression through modification of its microenvironment. The reduction of ovarian cancer cell surface sLe^x inhibits interaction with HMVEC and thus HMVEC differentiation into tubes, inhibits interaction with the local matrix reducing invasive behaviour, and causes cell injury initiating autophagy in tumour and vascular cells.     

Ovarian Stem Cells (OSCs) from the Cryopreserved Ovarian Cortex: A Potential for Neo-Oogenesis in Women with Cancer-Treatment Related Infertility: A Case Report and a Review of Literature

Cancer treatment related infertility (CTRI) affects more than one third of young women undergoing anti-cancer protocols, inducing a premature exhaustion of the ovarian reserve. In addition to ovarian suppression by GnRHa, oocyte and cortex cryopreservation has gained interest in patients with estrogen-sensitive tumors for whom the hormonal burst to prompt the multiple follicular growth could provide a further pro-life tumor pulsing. On the other hand, cortex reimplantation implies a few drawbacks due to the unknown consistency of the follicles to be reimplanted or the risk of reintroducing malignant cells. The capability of ovarian stem cells (OCSs) from fresh ovarian cortex fragments to differentiate in vitro to mature oocytes provides a tool to overcome these drawbacks. In fact, since ovarian cortex sampling and cryopreservation is practicable before gonadotoxic treatments, the recruitment of OSCs from defrosted fragments could provide a novel opportunity to verify their suitability to be expanded in vitro as oocyte like cells (OLCs). Here, we describe in very preliminary experiments the consistency of an OSC population from a single cryopreserved ovarian cortex after thawing as well as both their viability and their suitability to be further explored in their property to differentiate in OLCs, thus reinforcing interest in stemness studies in the treatment of female CTRI.     

Progesterone induces apoptosis in TRAIL-resistant ovarian cancer cells by circumventing c-FLIPL overexpression

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) holds great potential as an anticancer drug, since it induces selective cell death in cancer cells but not in normal ones. However, cancer cells often acquire resistance to TRAIL, which hinders its clinical efficacy. We previously demonstrated that progesterone triggers apoptosis in human ovarian cancer (OCa) cells. In the present study, we evaluated the prospect of utilizing progestins in combination with TRAIL to enhance cell death in TRAIL-sensitive (OVCA 420, OVCA 429, and OVCA 433) and -resistant (OVCA 432) OCa cell lines. TRAIL sensitivity (60-80% cell kill) bore no correlation with expression of the TRAIL receptors (DR4, DR5) or their decoys (DcR1 and DcR2), but was associated with activation of caspase-8 and -3, and downregulation of the long isoform of FLICE-like inhibitory protein (c-FLIP(L)), an anti-apoptosis mediator. Small interfering RNA-mediated knockdown of c-FLIP(L) expression restored TRAIL sensitivity in OVCA 432 cells. Induction of c-FLIP(L) overexpression increased TRAIL resistance in TRAIL-sensitive lines. Thus, persistent high level of c-FLIP(L) expression likely mediates TRAIL resistance in OCa cells. Treatment of OCa cells with progesterone enhanced TRAIL-induced cell death (>85%), but only in TRAIL-sensitive cell lines. Combined treatment with two progestins was superior to single progestin treatment, with progesterone plus medroxyprogesterone acetate (MPA) achieving over 85% cell kill in both TRAIL-sensitive and -resistant OCa cell lines. Significantly, unlike TRAIL, progestin-induced cell death did not involve c-FLIP(L) downregulation. Hence, combined progestin regimens, with or without TRAIL, may serve as an effective therapy for OCa by circumventing the anti-apoptotic action of c-FLIP(L).     

Zinc Finger E-Box Binding Homeobox 2 as a Prognostic Biomarker in Various Cancers and Its Correlation with Infiltrating Immune Cells in Ovarian Cancer

This study investigated the expression of zinc finger E-box binding homeobox 2 (ZEB2), its prognostic significance in various cancers, and the correlation between ZEB2 and infiltrating immune cells and ZEB2-related proteins in ovarian cancer (OV). The Gene Expression Profiling Interactive Analysis tool was used to analyze RNA sequencing data and cancer survival rates, based on normal and tumor tissue data available in The Cancer Genome Atlas (TCGA) database. The Kaplan–Meier plotter and PrognoScan databases were used to analyze the prognostic value of ZEB2 in OV (n = 1144). The Tumor Immune Estimation Resource was used to investigate the correlation between ZEB2 and infiltrating immune cells in various cancers, including OV. High ZEB2 expression was associated with a poorer prognosis in OV. In OV, ZEB2 is positively correlated with CD8+T cells, neutrophils, macrophages, and dendritic cell invasion; and ZEB2 is negatively correlated with tumor-infiltrating B cells. The STRING database was used to investigate the correlations with ZEB2-related proteins. The results reveal that ZEB2 was positively correlated with SMAD1 and SMAD2 in OV. Our findings may serve as a potential prognostic biomarker, and provide novel insights into the tumor immunology in OV. Thus, ZEB2 may be a potential diagnostic and therapeutic target in OV.