Journal

Cancer Biology & Therapy

Papers (33)

LCP1 promotes ovarian cancer cell resistance to olaparib by activating the JAK2/STAT3 signalling pathway

Resistance to poly (ADP-ribose) polymerase (PARP) inhibitors (PARPis) remain a major challenge in ovarian cancer (OC) treatment. However, the underlying mechanism of PARPi resistance is still poorly characterized. Increasing evidence has proven that lymphocyte cytosolic protein 1 (LCP1) promotes tumor progression. The JAK2/STAT3 signaling pathway plays an important role in increasing tumor metastatic ability and chemoresistance in cancer by promoting epithelial - mesenchymal transition (EMT). We established an olaparib-resistant OC cell line and studied its toxicologic effects through cell survival, Transwell, colony formation, western blotting and flow cytometry assays. RNA sequencing and screening were then performed to identify genes associated with olaparib resistance. Lymphocyte cytosolic protein 1 (LCP1) was found to be overexpressed in olaparib-resistant OC cells. The inhibition of cell survival and promotion of cell apoptosis induced by olaparib in parental cells were significantly attenuated in olaparib-resistant cells. LCP1 was upregulated in olaparib-resistant cells compared with parental OC cells. Moreover, we found that the protein levels of JAK2/STAT3 signaling pathway components and EMT markers were increased in olaparib-resistant cells. Overexpression of LCP1 increased olaparib resistance in OC cells, and knockdown of LCP1 attenuated olaparib resistance. The changes in the protein levels of JAK2/STAT3 signaling pathway members and EMT markers between the cell types were similar to the changes in the levels of LCP1. These findings indicate that LCP1 expression may play an important role in the resistance of OC to olaparib by activating the JAK2/STAT3 signaling pathway and EMT. LCP1 could be a potential therapeutic target for patients with OC who are resistant to olaparib. Our study provides a new mechanism of olaparib resistance.

TOP2A modulates signaling via the AKT/mTOR pathway to promote ovarian cancer cell proliferation

Ovarian cancer (OC) is a form of gynecological malignancy that is associated with worse patient outcomes than any other cancer of the female reproductive tract. Topoisomerase II α (TOP2A) is commonly regarded as an oncogene that is associated with malignant disease progression in a variety of cancers, its mechanistic functions in OC have yet to be firmly established. We explored the role of TOP2A in OC through online databases, clinical samples, in vitro and in vivo experiments. And initial analyses of public databases revealed high OC-related TOP2A expression in patient samples that was related to poorer prognosis. This was confirmed by clinical samples in which TOP2A expression was elevated in OC relative to healthy tissue. Kaplan-Meier analyses further suggested that higher TOP2A expression levels were correlated with worse prognosis in OC patients. In vitro, TOP2A knockdown resulted in the inhibition of OC cell proliferation, with cells entering G1 phase arrest and undergoing consequent apoptotic death. In rescue assays, TOP2A was confirmed to regulate cell proliferation and cell cycle through AKT/mTOR pathway activity. Mouse model experiments further affirmed the key role that TOP2A plays as a driver of OC cell proliferation. These data provide strong evidence supporting TOP2A as an oncogenic mediator and prognostic biomarker related to OC progression and poor outcomes. At the mechanistic level, TOP2A can control tumor cell growth via AKT/mTOR pathway modulation. These preliminary results provide a foundation for future research seeking to explore the utility of TOP2A inhibitor-based combination treatment regimens in platinum-resistant recurrent OC patients.

The RNA-binding protein ELAVL1 promotes Beclin1-mediated cellular autophagy and thus endometrial cancer development by affecting LncRNA-neat stability

Our study aims to investigate the roles of embryonic lethal abnormal vision-like 1 (ELAVL1) and long non-coding RNA (LncRNA) NEAT1 in endometrial cancer (EC), focusing on their underlying molecular mechanisms.We obtained EC cell lines (HEC-1A, Ishikawa, RL95-2, HEC-1B, and AN3CA) from ATCC. We used siRNAs (si-ELAVL1#1 and si-ELAVL1#2) and overexpression RNAs (OE ELAVL1 and OE-NEAT1) for knockdown or overexpression of ELAVL1 and LncRNA NEAT1. We also employed 3-MA (5mM) or rapamycin (100µM) to inhibit or promote autophagy. Moreover, we conducted RNA immunoprecipitation (RIP) assays to confirm the interaction between LncRNA NEAT1 and ELAVL1. Cell Counting Kit-8 (CCK-8) and transwell assays were utilized to assess cell proliferation and migration. Additionally, we measured the expression of ELAVL1 and Beclin1 through Western blotting and RT-qPCR.ELAVL1 was found to be highly expressed in EC. Furthermore, ELAVL1 promoted the proliferation, invasion, and migration of EC cells through the regulation of Beclin1-related pathways. RIP assays revealed a direct interaction between LncRNA NEAT1 and ELAVL1, with ELAVL1 stabilizing LncRNA NEAT1 mRNA in EC cells. Additionally, we observed that ELAVL1 influenced EC cell proliferation, invasion, and migration through the regulation of LncRNA NEAT1-mediated regulation of Beclin1 expression. Moreover, in an animal study, we determined that ELAVL1 influenced endometrial cancer tumor growth through its interaction with LncRNA NEAT1, which mediated Beclin1 expression in vivo.In summary, our study showed that ELAVL1 regulated the malignant behavior of endometrial cancer cells through the modulation of LncRNA NEAT1-mediated regulation of Beclin1 expression.

A novel dopamine receptor D2 antagonist (ONC206) potentiates the effects of olaparib in endometrial cancer

Poly ADP-ribose polymerase (PARP) inhibitors are effective therapies for cancer patients with homologous recombination (HR) deficient tumors. The imipridone ONC206 is an orally bioavailable dopamine receptor D2 antagonist and mitochondrial protease ClpP agonist that has anti-tumorigenic effects in endometrial cancer via induction of apoptosis, activation of the integrated stress response and modulation of PI3K/AKT signaling. Both PARP inhibitors and imipridones are being evaluated in endometrial cancer clinical trials but have yet to be explored in combination. In this manuscript, we evaluated the effects of the PARP inhibitor olaparib in combination with ONC206 in human endometrioid endometrial cancer cell lines and in a genetically engineered mouse model of endometrial cancer. Our results showed that simultaneous exposure of endometrial cancer cells to olaparib and ONC206 resulted in synergistic anti-proliferative effects and increased cellular stress and apoptosis in both cell lines, compared to either drug alone. The combination treatment also decreased expression of the anti-apoptotic protein Bcl-2 and reduced phosphorylation of AKT and S6, with greater effects compared to either drug alone. In the transgenic model of endometrial cancer, the combination of olaparib and ONC206 resulted in a more significant reduction in tumor weight in obese and lean mice compared to ONC206 alone or olaparib alone, together with a considerably decreased Ki-67 and enhanced H2AX expression in obese and lean mice. These results suggest that this novel dual therapy may be worthy of further exploration in clinical trials.

circ_C20orf11 enhances DDP resistance by inhibiting miR-527/YWHAZ through the promotion of extracellular vesicle-mediated macrophage M2 polarization in ovarian cancer

Ovarian cancer is a fatal gynecologic tumor, and conventional treatment is mainly limited by chemoresistance. The mechanism contributing to chemoresistance in ovarian cancer has yet to be established. This study aimed to investigate the specific role of circ_C20orf11 in regulating chemoresistance to cisplatin (DDP)in ovarian cancer. We first established two DDP-resistant ovarian cancer cell lines. Then, we identified the effect of circ_C20orf11 on specific cellular characteristics (proliferation, apoptosis, DDP resistance) via a series of experiments. The binding sites between circ_C20orf11 and miR-527 and between miR-527 and YWHAZ were predicted using a bioinformatics tool and confirmed with a dual-luciferase reporter assay. Furthermore, extracellular vesicles (EVs) derived from DDP-resistant cell lines were identified, and the effect of EVs on macrophage polarization was examined. circ_C20orf11 was upregulated in ovarian cancer. Increased circ_C20orf11 expression enhanced DDP resistance and cell proliferation and reduced cell apoptosis in DDP-resistant cell lines after DDP treatment by sponging miR-527 and promoting YWHAZ expression. In addition, we found that DDP-resistant cell-derived EVs can induce macrophage M2 polarization, whereas silencing of circ_C20orf11 inhibited EV-induced macrophage M2 polarization. Consistent with these results, silencing of circ_C20orf11 enhanced sensitivity to DDP in vivo. Importantly, we proved that circ_C20orf11 expression was upregulated in EVs extracted from the serum of DDP-resistant patients. Our study demonstrated that silencing circ_C20orf11 sensitizes ovarian cancer to DDP by promoting miR-527/YWHAZ signaling and EV-mediated macrophage M2 polarization.

Circular RNA hsa_circ_0003204 promotes cervical cancer cell proliferation, migration, and invasion by regulating MAPK pathway

Cervical cancer (CC) is the second most common malignancy in women worldwide. The mechanism underlying CC development remains unclear. Recently, Circular RNAs (circRNAs)have attracted attention because of its role in tumorigenesis. To investigate circRNAsin CC, RNA sequencing was employed to characterize circRNA expression profile between CC tissues and matched adjacent normal tissues. The expression of hsa_circ_0003204 was examined in CC tissues and cell lines by real-time PCR. Migration assay and invasion assay were used to verify the effect of hsa_circ_0003204 on migration and invasion ability in CC cell lines. Tumor formation assay in nude mice was used to analyze the effect of hsa_circ_0003204 on the tumorigenicity of CC cell lines in vitro. Western blotting analyzes were performed to investigate the role of hsa_circ_0003204 in the regulation of MAPK signaling activation. We found that circRNA hsa_circ_0003204 was significantly upregulated in CC tissues. The function and potential molecular mechanisms of hsa_circ_0003204 were also investigated in vitro and in vivo. Hsa_circ_0003204 knockdown reduced cell growth, migration, and invasion but promoted cells apoptosis. However, the over-expression of hsa_circ_0003204 had the opposite effect. The MAPK pathway was different in hsa_circ_0003204 over-expression or down-expression cells, compared to parental cells. In addition, over-expression of hsa_circ_0003204 significantly increased tumor volume and tumor weight in vivo.Taken together, results indicated hsa_circ_0003204 may serve as a potential therapeutic target for patients with CC.

A positive feedback loop of SRSF9/USP22/ZEB1 promotes the progression of ovarian cancer

Ovarian cancer (OC) is recognized as the most lethal type of gynecological malignancy, making treatment options challenging. Discovering novel therapeutic targets will benefit OC patients. This study aimed to reveal the mechanism by which SRSF9 regulates OC progression. Cell proliferation was determined via CCK-8 assays, whereas cell migration and invasion were monitored via Transwell assays. Western blotting and qPCR assays were used to detect protein and mRNA alterations. RNA pull-down, RNA immunoprecipitation (RIP), and actinomycin D experiments were performed to investigate the relationships between SRSF9 and USP22. Co-IP was used to validate the interaction between USP22 and ZEB1. Chromatin immunoprecipitation (ChIP) and dual-luciferase reporter assays were used to verify the regulatory effect of ZEB1 on the transcription of SRSF9. Subcutaneous xenograft models were established to evaluate the impact of SRSF9 on tumor development. Knockdown of SRSF9 significantly suppressed the proliferation, invasion, migration, tumorigenicity, and epithelial‒mesenchymal transition (EMT) of OC cells. SRSF9 can bind to USP22 mRNA, increasing its stability. Moreover, the overexpression of USP22 reversed the impact of SRSF9 silencing on malignant phenotypes. USP22 can mediate the deubiquitination of ZEB1, thereby enhancing the progression of OC. Furthermore, ZEB1 upregulated SRSF9 expression through transcriptional activation, thus establishing a positive feedback loop. SRSF9 enhanced the malignant characteristics of OC through a positive feedback loop of SRSF9/USP22/ZEB1. This functional circuit may help in the development of novel therapeutic approaches for treating OC.

The therapeutic potential of exosomal miR-22 for cervical cancer radiotherapy

Cervical cancer is the fourth-most prevalent malignancy in women. For advanced cervical cancer, radiotherapy is a major treatment. Micro RNAs (miRNAs) are small, noncoding RNAs that negatively regulate the target gene expression posttranscriptionally. miR-22 is frequently downregulated in various cancers including cervical cancer, and is associated with a poor prognosis in cervical cancer. Exosomes are small endosomally secreted vesicles that carry components such as proteins, messenger RNA (mRNA), DNA and miRNA. We investigated whether or not exosomes can efficiently deliver miR-22 to recipient cervical cancer cells and affect the gene expression in the cells, as well as assessed the role of exosomal miR-22 in radiosensitivity. Exosomes containing high levels of miR-22 were extracted by ultracentrifugation and then characterized by Western blotting, a nanoparticle tracking analysis and electron microscopy. The high presence of miR-22 in the exosome was confirmed by real-time polymerase chain reaction. After the administration of the collected exosomal miR-22 to SKG-II and C4-I cervical cancer cells, the level of miR-22 in the cells was significantly increased, indicating the absorption of the exosomal miR-22. When miR-22 encapsulated in exosomes was administered to the SKG-II cells, the level of c-Myc binding protein (MYCBP) and human telomerase reverse transcriptase (hTERT) was significantly decreased in correlation with increased radiosensitivity determined by a clonogenic assay. Taken together, these results suggest that the administration of exosomal miR-22 may be a novel drug delivery system for cervical cancer radiotherapy.

Exosomal taurine up-regulated 1 promotes angiogenesis and endothelial cell proliferation in cervical cancer

Emerging evidence had highlighted that exosomes could mediate cell-cell communication in human cancerous development via transferring the various molecular cargos, including long non-coding RNA (lncRNA). Taurine up-regulated 1 (TUG1) was previously reported as an oncogenic lncRNA in cervical cancer (CC) via facilitating cell proliferation and other vital biological behaviors. Nevertheless, the presence of TUG1 in exosomes and the functional regulation of exosomal TUG1 in CC are still elusive. The current study aimed at the communication between CC cell lines and endothelial cell-mediated by exosomes, as well as the roles of exosomes derived from CC cells and exosomal TUG1 in affecting angiogenesis. Initially, it was found that TUG1 expression was upregulated in both CC cells and their secreted exosomes. TUG1 was transferred from CC cells to recipient human umbilical vein endothelial cells (HUVECs) in the exosomes way. Interestingly, TUG1 depletion impaired the exosomes-mediated proangiogenic potential of HUVECs by modulating certain key angiogenesis-related genes. In addition, exosomal TUG1 contributed to HUVECs proliferation through suppressing caspase-3 activity and impacting apoptosis-related proteins. Collectively, we identified a new exosomes-mediated molecular mechanism by which CC cells transferred TUG1 via exosomes to recipient HUVECs, thus promoting angiogenesis, providing a promising target for early diagnosis of CC.

Publisher

Informa UK Limited

ISSN

1538-4047