The Role of GDF15 in Regulating the Canonical Pathways of the Tumor Microenvironment in Wild-Type p53 Ovarian Tumor and Its Response to Chemotherapy.
ABSTRACT: BACKGROUND:The standard treatment of ovarian cancer is surgery followed by a chemotherapeutic combination consisting of a platinum agent, such as cisplatin and a taxane-like paclitaxel. We previously observed that patients with ovarian cancer wild-type for p53 had a poorer survival rate than did those with p53 mutations. Thus, a better understanding of the molecular changes of epithelial ovarian cancer cells with wild-type p53 in response to treatment with cisplatin could reveal novel mechanisms of chemoresistance. METHODS:Gene expression profiling was performed on an ovarian cancer cell line A2780 with wild-type p53 treated with cisplatin. A gene encoding a secretory protein growth differentiation factor 15 (GDF15) was identified to be highly induced by cisplatin treatment in vitro. This was further validated in a panel of wild-type and mutant p53 ovarian cancer cell lines, as well as in mouse orthotopic models. The mouse tumor tissues were further analyzed by histology and RNA-seq. RESULTS:GDF15 was identified as one of the highly induced genes by cisplatin or carboplatin in ovarian cancer cell lines with wild-type p53. The wild-type p53-induced expression of GDF15 and GDF15-confered chemotherapy resistance was further demonstrated in vitro and in vivo. This study also discovered that GDF15-knockdown (GDF15-KD) tumors had less stromal component and had different repertoires of activated and inhibited canonical pathways in the stromal cell and cancer cell components from that of the control tumors after cisplatin treatment. CONCLUSIONS:GDF15 expression from the wild-type p53 cancer cells can modulate the canonical pathways in the tumor microenvironment in response to cisplatin, which is a possible mechanism of chemoresistance.
Project description:As a component of p53-dependent lncRNA (long non-coding RNA), PANDAR (the promoter of CDKN1A antisense DNA damage activated RNA) participates in the epigenetic regulation in human cancer. However, the involvement of PANDAR in cancer chemoresistance is unknown. In this study, we report that PANDAR serves as a negative regulator of cisplatin sensitivity in human ovarian cancer via PANDAR-SRFS2-p53 feedback regulation in nuclear. Our data showed that among the drugs commonly used in ovarian cancer therapy, cisplatin induces higher levels of PANDAR compared with doxorubicin and paclitaxel. We also proved that PANDAR exhibited higher expression in cisplatin-resistant ovarian cancer tissues and cells, compared with cisplatin-sensitive ones, and this expression pattern depends on wild-type p53 (wt-p53), not mutant-p53 (mt-p53). In vitro and in vivo, PANDAR overexpression improved cell survival rate and tumor growth in response to cisplatin, while depletion of PANDAR leads to a reduced tumor growth. Further investigation revealed that PANDAR-reduced cisplatin sensitivity was likely or partly due to the PANDAR-binding protein SFRS2 (arginine/serine-rich 2), a splicing factor with the ability to negative regulate p53 and its phosphorylation at Serine 15 (Ser15). This feedback regulation of PANDAR-SFRS2-p53 leads to a reduced transactivation of p53-related pro-apoptotic genes, such as PUMA (p53-upregulated modulator of apoptosis). In addition, in platinum-treated patients with relapsed ovarian cancer, resistant period was positively correlated with the expression of PANDAR and SFRS2, and inversely associated with expression of p53-Ser15 and PUMA in these clinical tissues. Last but not least, the role of PANDAR in chemoresistance was confirmed in patients with ovarian cancer. These findings reveal a novel regulatory maneuver of cancer cells in response to chemostress, and might shed light on overcoming cisplatin resistance in ovarian cancer.
Project description:The interplay between p53 and RAS signaling regulates cancer chemoresistance, but the detailed mechanism is unclear. In this study, we investigated the interactive effects of p53 and RAS on ovarian cancer cisplatin resistance to explore the potential therapeutic targets. Methods: An inducible p53 and RAS mutants active in either MAPK/ERK (S35 and E38) or PI3K/AKT (C40) or both (V12) were sequentially introduced into a p53-null ovarian cancer cell line-SKOV3. Comparative microarray analysis was performed using Gene Chip Prime View Human Gene Expression arrays (Affymetrix). In vitro assays of autophagy and apoptosis and in vivo animal experiments were performed by p53 induction and/or cisplatin treatment using the established cell lines. The correlation between HDAC4 and HIF-1α or CREBZF and the association of HDAC4, HIF-1α, CREBZF, ERK, AKT, and p53 mRNA levels with patient survival in 523 serous ovarian cancer cases from TCGA was assessed. Results: We show that p53 and RAS mutants differentially control cellular apoptosis and autophagy to inhibit or to promote chemoresistance through dysregulation of Bax, Bcl2, ATG3, and ATG12. ERK and AKT active RAS mutants are mutually suppressive to confer or to deprive cisplatin resistance. Further studies demonstrate that p53 induces HIF-1α degradation and HDAC4 cytoplasmic translocation and phosphorylation. S35, E38, and V12 but not C40 promote HDAC4 phosphorylation and its cytoplasmic translocation along with HIF-1α. Wild-type p53 expression in RAS mutant cells enhances HIF-1α turnover in ovarian and lung cancer cells. Autophagy and anti-apoptotic processes can be promoted by the overexpression and cytoplasmic translocation of HDAC4 and HIF1-α. Moreover, the phosphorylation and cytoplasmic translocation of HDAC4 activate the transcription factor CREBZF to promote ATG3 transcription. High HDAC4 or CREBZF expression predicted poor overall survival (OS) and/or progression-free survival (PFS) in ovarian cancer patients, whereas high HIF-1α expression was statistically correlated with poor or good OS depending on p53 status. Conclusion: HIF-1α and HDAC4 may mediate the interaction between p53 and RAS signaling to actively control ovarian cancer cisplatin resistance through dysregulation of apoptosis and autophagy. Targeting HDAC4, HIF-1α and CREBZF may be considered in treatment of ovarian cancer with p53 and RAS mutations.
Project description:Tumour cell-selective activation of apoptosis by recombinant human TNF-related apoptosis-inducing ligand (rhTRAIL) is enhanced through co-activation of p53 by chemotherapeutic drugs. The novel anticancer agent nutlin-3 provides a promising alternative for p53 activation by disrupting the interaction between p53 and its negative feedback regulator MDM2.We examined whether nutlin-3 enhances apoptosis induction by rhTRAIL and the DR5-selective TRAIL variant D269H/E195R in wild-type p53-expressing ovarian, colon and lung cancer cell lines and in an ex vivo model of human ovarian cancer.Nutlin-3 enhanced p53, p21, MDM2 and DR5 surface expression. Although nutlin-3 did not induce apoptosis, it preferentially enhanced D269H/E195R-induced apoptosis over rhTRAIL. Combination treatment potentiated the cleavage of caspases 8, 9, 3 and PARP. P53 and MDM2 siRNA experiments showed that this enhanced apoptotic effect was mediated by wild-type p53. Indeed, nutlin-3 did not enhance rhTRAIL-induced apoptosis in OVCAR-3 cells harbouring mutant p53. Addition of the chemotherapeutic drug cisplatin to the combination further increased p53 and DR5 levels and rhTRAIL- and D269H/E195R-induced apoptosis. As a proof of concept, we show that the combination of D269H/E195R, nutlin-3 and cisplatin induced massive apoptosis in ex vivo tissue slices of primary human ovarian cancers.Nutlin-3 is a potent enhancer of D269H/E195R-induced apoptosis in wild-type p53-expressing cancer cells. Addition of DNA-damaging agents such as cisplatin further enhances DR5-mediated apoptosis.
Project description:Epithelial ovarian cancer (EOC) is the leading cause of gynecological cancer death in the United States. Cisplatin is a DNA damaging agent initially effective against EOC but limited by resistance. P53 plays a critical role in cellular response to DNA damage and has been implicated in EOC response to platinum chemotherapy. In this study, we examined the role of p53 status in EOC response to a novel combination of cisplatin, sodium arsenite, and hyperthermia. Human EOC cells were treated with cisplatin ± 20?M sodium arsenite at 37°C or 39°C for 1 h. Sodium arsenite ± hyperthermia sensitized wild-type p53-expressing (A2780, A2780/CP70, OVCA 420, OVCA 429, and OVCA 433) EOC cells to cisplatin. Hyperthermia sensitized p53-null SKOV-3 and p53-mutant (OVCA 432 and OVCAR-3) cells to cisplatin. P53 small interfering RNA (siRNA) transfection abrogated sodium arsenite sensitization effect. XPC, a critical DNA damage recognition protein in global genome repair pathway, was induced by cisplatin only in wild-type p53-expressing cells. Cotreatment with sodium arsenite ± hyperthermia attenuated cisplatin-induced XPC in wild-type p53-expressing cells. XPC siRNA transfection sensitized wild-type p53-expressing cells to cisplatin, suggesting that sodium arsenite ± hyperthermia attenuation of XPC is a mechanism by which wild-type p53-expressing cells are sensitized to cisplatin. Hyperthermia ± sodium arsenite enhanced cellular and DNA accumulation of platinum in wild-type p53-expressing cells. Only hyperthermia enhanced platinum accumulation in p53-null cells. In conclusion, sodium arsenite ± hyperthermia sensitizes wild-type p53-expressing EOC cells to cisplatin by suppressing DNA repair protein XPC and increasing cellular and DNA platinum accumulation.
Project description:Ovarian cancer is the fifth leading cause of cancer-related female deaths. Due to serious side effects, relapse and resistance to standard chemotherapy, better and more targeted approaches are required. Mutation of the TP53 gene accounts for 50% of all human cancers. In the remaining malignancies, non-genotoxic activation of wild-type p53 by small molecule inhibition of the MDM2-p53 binding interaction is a promising therapeutic strategy. Proof of concept was established with the cis-imidazoline Nutlin-3, leading to the development of RG7388 and other compounds currently in early phase clinical trials. This preclinical study evaluated the effect of Nutlin-3 and RG7388 as single agents and in combination with cisplatin in a panel of ovarian cancer cell lines. Median-drug-effect analysis showed Nutlin-3 or RG7388 combination with cisplatin was additive to, or synergistic in a p53-dependent manner, resulting in increased p53 activation, cell cycle arrest and apoptosis, associated with increased p21WAF1 protein and/or caspase-3/7 activity compared to cisplatin alone. Although MDM2 inhibition activated the expression of p53-dependent DNA repair genes, the growth inhibitory and pro-apoptotic effects of p53 dominated the response. These data indicate that combination treatment with MDM2 inhibitors and cisplatin has synergistic potential for the treatment of ovarian cancer, dependent on cell genotype.
Project description:Cisplatin-based combination chemotherapy regimen is a reasonable alternative to cystectomy in advanced/metastatic bladder cancer, but acquisition of cisplatin resistance is common in patients with bladder cancer. Previous studies showed that loss of homeodomain-interacting protein kinase-2 (HIPK2) contributes to cell proliferation and tumorigenesis. However, the role of HIPK2 in regulating chemoresistance of cancer cell is not fully understood. In the present study, we found that HIPK2 mRNA and protein levels are significantly decreased in cisplatin-resistant bladder cancer cell in vivo and in vitro. Downregulation of HIPK2 increases the cell viability in a dose- and time-dependent manner during cisplatin treatment, whereas overexpression of HIPK2 reduces the cell viability. HIPK2 overexpression partially overcomes cisplatin resistance in RT4-CisR cell. Furthermore, we showed that Wip1 (wild-type p53-induced phosphatase 1) expression is upregulated in RT4-CisR cell compared with RT4 cell, and HIPK2 negatively regulates Wip1 expression in bladder cancer cell. HIPK2 and Wip1 expression is also negatively correlated after cisplatin-based combination chemotherapy in vivo. Finally, we demonstrated that overexpression of HIPK2 sensitizes chemoresistant bladder cancer cell to cisplatin by regulating Wip1 expression.These data suggest that HIPK2/Wip1 signaling represents a novel pathway regulating chemoresistance, thus offering a new target for chemotherapy of bladder cancer.
Project description:Little is known about the mechanisms that underlie Brca1-associated ovarian tumorigenesis, mainly due to the lack of an appropriate experimental model. We developed genetically defined primary mouse ovarian surface epithelial (OSE) cell lines in which the loss of functional Brca1 and p53 recapitulates the events that are thought to occur in early ovarian cancer development in patients with Brca1 mutations. This system allows for the introduction of additional oncogenes that are thought to cooperate with the loss of Brca1 and p53 to induce tumorigenesis. We showed that Myc is sufficient to induce transformation of ovarian cells that are deficient for both Brca1 and p53 but not sufficient for the transformation of cells that are deficient for either Brca1 or p53. The transformed Brca1-deficient OSE cells display an increased number of centrosomes, acquire complex chromosome aberrations, and lack Rad51 nuclear foci in the presence of DNA-damaging agents, such as mitomycin C and cisplatin. Immunocompetent mice injected with transformed OSE cells develop tumors that resemble human metastatic serous ovarian carcinoma, the most common type of ovarian cancer in women. Consistent with the reported platinum chemosensitivity in patients with Brca1-associated ovarian cancer, the Brca1-deficient OSE cells have increased sensitivity to the DNA-damaging agent cisplatin, whereas sensitivity to the microtubule poison paclitaxel is similar between Brca1 wild-type and Brca1-deficient cells. The Brca1 wild-type and Brca1-deficient mouse ovarian tumors and cell lines provide a new experimental system for the evaluation of therapies that target the Brca1 pathway.
Project description:Chemoresistance to anti-cancer drugs substantially reduces survival in epithelial ovarian cancer. In this study, we showed that chemoresistance to cisplatin and paclitaxel induced the epithelial-mesenchymal transition (EMT) and a stem cell phenotype in ovarian cancer cells. Chemoresistance was associated with the downregulation of epithelial markers and the upregulation of mesenchymal markers, EMT-related transcription factors, and cancer stem cell markers, which enhanced invasion and sphere formation ability. Overexpression of FOXM1 increased cisplatin-resistance and sphere formation in cisplatin-sensitive and low FOXM1-expressing ovarian cancer cells. Conversely, depletion of FOXM1 via RNA interference reduced cisplatin resistance and sphere formation in cisplatin-resistant and high FOXM1-expressing cells. Overexpression of FOXM1 also increased the expression, nuclear accumulation, and activity of ?-CATENIN in chemoresistant cells, whereas downregulation of FOXM1 suppressed these events. The combination of cisplatin and the FOXM1 inhibitor thiostrepton inhibited the expression of stem cell markers in chemoresistant cells and subcutaneous ovarian tumor growth in mouse xenografts. In an analysis of 106 ovarian cancer patients, high FOXM1 levels in tumors were associated with cancer progression and short progression-free intervals. Collectively, our findings highlight the importance of FOXM1 in chemoresistance and suggest that FOXM1 inhibitors may be useful for treatment of ovarian cancer.
Project description:BACKGROUND:High-grade serous ovarian cancer (HGSOC) is the most lethal of all gynecological malignancies. Patients often suffer from chemoresistance. Several studies have reported that Fn14 could regulate migration, invasion, and angiogenesis in cancer cells. However, its functional role in chemoresistance of HGSOC is still unknown. METHODS:The expression of Fn14 in tissue specimens was detected by IHC. CCK-8 assay was performed to determine changes in cell viability. Apoptosis was measured by flow cytometry. The potential molecular mechanism of Fn14-regulated cisplatin resistance in HGSOC was investigated using qRT-PCR, western blotting, and Co-IP assays. The role of Fn14 in HGSOC was also investigated in a xenograft mouse model. RESULTS:In this study, we found that Fn14 was significantly downregulated in patients with cisplatin resistance. Patients with low Fn14 expression were associated with shorter progression-free survival and overall survival. Overexpression of Fn14 suppressed cisplatin resistance in OVCAR-3 cells, whereas knockdown of Fn14 did not affect cisplatin resistance in SKOV-3 cells. Interestingly, Fn14 could exert anti-chemoresistance effect only in OVCAR-3 cells harboring a p53-R248Q mutation, but not in SKOV-3 cells with a p53-null mutation. We isolated and identified primary cells from two patients with the p53-R248Q mutation from HGSOC patients and the anti-chemoresistance effect of Fn14 was observed in both primary cells. Mechanistic studies demonstrated that overexpression of Fn14 could reduce the formation of a Mdm2-p53-R248Q-Hsp90 complex by downregulating Hsp90 expression, indicating that degradation of p53-R248Q was accelerated via Mdm2-mediated ubiquitin-proteasomal pathway. CONCLUSION:Our findings demonstrate for the first time that Fn14 overcomes cisplatin resistance through modulation of the degradation of p53-R248Q and restoration of Fn14 expression might be a novel strategy for the treatment of HGSOC.
Project description:Previous studies have shown aberrant expression of miR-214 in human malignancy. Elevated miR-214 is associated with chemoresistance and metastasis. In this study, we identified miR-214 regulation of ovarian cancer stem cell (OCSC) properties by targeting p53/Nanog axis. Enforcing expression of miR-214 increases, whereas knockdown of miR-214 decreases, OCSC population and self-renewal as well as the Nanog level preferentially in wild-type p53 cell lines. Furthermore, we found that p53 is directly repressed by miR-214 and that miR-214 regulates Nanog through p53. Expression of p53 abrogated miR-214-induced OCSC properties. These data suggest the critical role of miR-214 in OCSC via regulation of the p53-Nanog axis and miR-214 as a therapeutic target for ovarian cancer.