Jinjin Yu

Overexpression of long non-coding RNA HOTAIR leads to chemoresistance by activating the Wnt/β-catenin pathway in human ovarian cancer

Overexpression of HOTAIR (HOX antisense intergenic RNA) is significantly correlated with tumor progression and poor prognosis in human ovarian cancer. However, the underlying mechanisms are largely unknown. In the present study, we investigated the roles of HOTAIR in the initiation and chemoresistance of ovarian cancer. As our data show, HOTAIR overexpression promoted cell cycle progression (and thus cell proliferation) by activating the wnt/β-catenin signaling pathway. Likewise, knockdown of HOTAIR suppressed cell proliferation and arrested cell cycle at G1 phase via inhibition of wnt/β-catenin signaling. Moreover, the results of primary culture demonstrated that elevated HOTAIR expression correlated positively with chemoresistance in ovarian cancer. In vitro and in vivo, HOTAIR induced cellular resistance to cisplatin by activating the wnt/β-catenin pathway, which could be reversed by pre-treatment with the wnt/β-catenin inhibitor, XAV939. In conclusion, HOTAIR promotes the initiation and chemoresistance of ovarian cancer by activating wnt/β-catenin signaling, suggesting that HOTAIR might be a potent therapeutic target for ovarian cancer treatment.

A high level of circulating HOTAIR is associated with progression and poor prognosis of cervical cancer

We recently found that HOTAIR (HOX antisense intergenic RNA) promotes development and induces radioresistance in cervical cancer. In the present study, we investigated the circulating HOTAIR expression and determined its relationships with the clinicopathological parameters in cervical cancer. The sera samples were obtained from 118 pathological diagnosed cervical cancer patients and 100 normal age-matched women. The expression of HOTAIR was measured by quantitative real time PCR. Patients’ information were collected and analyzed by the SPSS 17.0 software. Compared with normal control, the expression of HOTAIR was significantly upregulated in the sera of cervical cancer patients (P < 0.0001). In addition, elevated HOTAIR was associated with advanced tumor stages (P < 0.0001), adenocarcinoma (P < 0.0001), lymphatic vascular space invasion (P = 0.0065), and lymphatic node metastasis (P = 0.0259). In addition, our follow-up data showed that high HOTAIR was notably correlated with tumor recurrence (P = 0.013) and short overall survival (P = 0.009). Circulating HOTAIR was commonly upregulated and a potent prognostic marker in cervical cancer.

RPRD1B promotes tumor growth by accelerating the cell cycle in endometrial cancer

RPRD1B, the regulation of nuclear pre-mRNA domain containing 1B gene, functions as a cell cycle manipulator and has been found overexpressed in a small panel of endometrial cancer types. In the present study, we investigated the roles of RPRD1B in endometrial cancer using various in vitro and in vivo experiments. According to our results, RPRD1B mRNA was significantly upregulated in endometrial cancer tissues (P=0.0012). RPRD1B overexpression was correlated with tumor stage (P=0.0004), histology type (P=0.0146) and depth of myometrial invasion (P=0.024). In vitro, RPRD1B promoted cellular proliferation (P=0.032 for MTT assay and P=0.018 for colony formation assay), and accelerated the cell cycle (P=0.007) by upregulating cyclin D1, CDK4 and CDK6, while knockdown of RPRD1B suppressed cellular proliferation (P=0.02 for MTT assay and P=0.031 for colony formation assay), and led to G1 phase arrest (P=0.025) through downregulating cyclin D1, CDK4 and CDK6. Consistently, in the nude mice model, RPRD1B overexpression significantly accelerated the tumor xenograft growth (P=0.0012), accompanied by elevated Ki-67 and cyclin D1. In addition, we demonstrated that downregulating RPRD1B could sensitize Ishikawa cells to Raloxifene (P=0.01). In summary, we demonstrated that RPRD1B was frequently overexpressed in human endometrial cancer. Both in vitro and in vivo, over-abundant RPRD1B could promote tumor growth and accelerate cellular cell cycle. In addition, knockdown of RPRD1B also increased cell sensitivity to Raloxifene, making RPRD1B a potent therapeutic target for endometrial cancer, particularly in patients with resistance to the selective ER modulators.

Over-expression of platelet-derived growth factor-D promotes tumor growth and invasion in endometrial cancer.

The platelet-derived growth factor-D (PDGF-D) was demonstrated to be able to promote tumor growth and invasion in human malignancies. However, little is known about its roles in endometrial cancer. In the present study, we investigated the expression and functions of PDGF-D in human endometrial cancer. Alterations of PDGF-D mRNA and protein were determined by real time PCR, western blot and immunohistochemical staining. Up-regulation of PDGF-D was achieved by stably transfecting the pcDNA3-PDGF-D plasmids into ECC-1 cells; and knockdown of PDGF-D was achieved by transient transfection with siRNA-PDGF-D into Ishikawa cells. The MTT assay, colony formation assay and Transwell assay were used to detect the effects of PDGF-D on cellular proliferation and invasion. The xenograft assay was used to investigate the functions of PDGF-D in vivo. Compared to normal endometrium, more than 50% cancer samples showed over-expression of PDGF-D (p < 0.001), and high level of PDGF-D was correlated with late stage (p = 0.003), deep myometrium invasion (p < 0.001) and lympha vascular space invasion (p = 0.006). In vitro, over-expressing PDGF-D in ECC-1 cells significantly accelerated tumor growth and promoted cellular invasion by increasing the level of MMP2 and MMP9; while silencing PDGF-D in Ishikawa cells impaired cell proliferation and inhibited the invasion, through suppressing the expression of MMP2 and MMP9. Moreover, we also demonstrated that over-expressed PDGF-D could induce EMT and knockdown of PDGF-D blocked the EMT transition. Consistently, in xenografts assay, PDGF-D over-expression significantly promoted tumor growth and tumor weights. We demonstrated that PDGF-D was commonly over-expressed in endometrial cancer, which was associated with late stage deep myometrium invasion and lympha vascular space invasion. Both in vitro and in vivo experiments showed PDGF-D could promote tumor growth and invasion through up-regulating MMP2/9 and inducing EMT. Thus, we propose targeting PDGF-D to be a potent strategy for endometrial cancer treatment.

TESTIN was commonly hypermethylated and involved in the epithelial-mesenchymal transition of endometrial cancer.

We previously reported frequent loss of TESTIN in human endometrial carcinoma, which significantly suppressed tumor proliferation and invasion. Herein, we further explored the mechanisms underlying TESTIN loss and its roles in the epithelial‐mesenchymal transition (EMT, a key step for tumor spreading). Methylation‐specific PCR was performed to investigate the promoter status of TESTIN in a panel of endometrial cancer and normal endometrium tissues. The expression of TESTIN mRNA was determined by real‐time PCR. Up‐ and down‐regulation of TESTIN were achieved by transient transfection with pcDNA3.1‐TESTIN and shRNA‐TESTIN plasmids, respectively. The EMT alterations were observed under the optical microscope and EMT‐related markers were detected by real‐time PCR and western blot. Compared to the control (3.6%), TESTIN was hypermethylated in 43.7% endometrial cancer tissues (p < 0.001). Moreover, TESTIN hypermethylation was significantly correlated with advanced tumor stage, deep myometrial invasion and lymphatic node metastasis. In vitro, the demethylating agent dramatically restored the expression of TESTIN. In addition, up‐regulation of TESTIN significantly suppressed the EMT procedure; whereas down‐regulation of TESTIN enhanced EMT. In conclusion, we demonstrated that loss of TESTIN was mainly caused by hypermethylation, which might be a potent prognostic marker. Furthermore, we proved that TESTIN significantly suppressed the EMT procedure, proposing restoration of TESTIN to be a novel therapeutic strategy for endometrial carcinoma.

Frequent Loss of NISCH Promotes Tumor Proliferation and Invasion in Ovarian Cancer via Inhibiting the FAK Signal Pathway.

NISCH encodes the imidazoline receptor Nischarin and is a known tumor suppressor in many human malignancies; however, its roles in ovarian cancer are still largely unknown. Here, we aim to investigate the biologic functions of NISCH in ovarian cancer. We found that NISCH was significantly downregulated, which correlated considerably with advanced tumor stage, poor differentiation, lymph node metastasis, and the serous/mucinous subtypes in a panel of ovarian cancer tissues. Moreover, NISCH gene silencing was mainly the product of promoter hypermethylation, which could be reversed by treatment with 5-aza-dC. In vitro, NISCH overexpression suppressed cell proliferation and colony formation by hindering cell-cycle progression, whereas the opposite was observed in NISCH knockdown counterparts. In vivo, abundant NISCH expression hindered the growth of HO8910 xenografts, whereas NISCH knockdown accelerated the growth of SKOV3 xenografts. In addition, NISCH significantly attenuated cell invasion by inhibiting the phosphorylation of FAK and ERK, which could be neutralized by PF-562271 (a FAK/Pyk2 inhibitor). Accordingly, NISCH knockdown xenografts exhibited increased peritoneal/pelvic metastases that were not present in counterparts treated with PF-562271. Furthermore, NISCH expression in primary ovarian cancer cells predicted a cellular resistance to PF-562271. In conclusion, we showed that NISCH was frequently silenced by promoter hypermethylation in human ovarian cancer. NISCH manipulated cellular proliferation and invasion by arresting cell cycle and inhibiting the FAK signal. Our findings revealed the biologic functions of NISCH in ovarian cancer, and might be useful for treating patients with aberrant expression of NISCH. Mol Cancer Ther; 14(5); 1202–12. ©2015 AACR.

Restoration of microRNA‑218 increases cellular chemosensitivity to cervical cancer by inhibiting cell‑cycle progression.

We previously reported frequent loss of microRNA‑218 (miR‑218) in human cervical cancer, which was associated with tumor progression and poor prognosis. In this study, we investigated whether restoration of the miR‑218 level is a valid strategy for the treatment of cervical cancer. The expression of miR‑218 in cervical cancer samples and cell lines was quantified by reverse transcription TaqMan quantitative (RT‑q)PCR. Overexpression of miR‑218 was achieved by both transient and stable transfection, using a miR‑218 mimic and a miR‑218‑expressing plasmid, respectively. Alterations in cellular proliferation and cell‑cycle progression were measured by the MTT assay and flow cytometry analysis. Nude mice bearing SiHa xenografts were used to investigate the functions of miR‑218 and carboplatin on tumor growth and weight. The expression of cycle‑related proteins was detected by western blotting and immunohistochemical staining. In vitro, miR‑218 significantly inhibited cellular growth in all four cell lines tested (P=0.021 for CaSki, P=0.009 for HeLa, P=0.016 for SiHa, and P=0.029 for C33A). Overexpression of miR‑218 induced G1 phase arrest and reduced expression of cyclin D1 and CDK4. In vivo, restoration of miR‑218 notably inhibited tumor growth and decreased tumor weight. In primary cultured samples, tumors with high levels of miR‑218 were more sensitive to carboplatin (R2=0.3319, P=0.0026); consistently, miR‑218 overexpression suppressed tumor growth, induced cell‑cycle arrest, and reduced the cyclin D1 level. Based on these and previous results, we conclude that restoration of the miR‑218 level inhibits the growth of cervical cancer cells both in vitro and in vivo; furthermore, overexpression of miR‑218 sensitizes cervical cancer cells to carboplatin. Our findings suggest a novel therapy for cervical cancer based on miR‑218, especially in patients with reduced levels of miR‑218.

The poly (ADP-ribose) polymerase inhibitor rucaparib suppresses proliferation and serves as an effective radiosensitizer in cervical cancer

SummaryObjectives Our goal was to investigate the effects of rucaparib on the proliferation of cervical cancer cells and sensitivity to radiotherapy. Methods We used the human cervical cancer cell lines Hela and Siha and evaluated their viability and activity using various methods. Cellular proliferation was assessed by CCK-8 and clonogenic assays after treatment with rucaparib. Cell cycle analysis was performed using propidium iodide staining. Western immunoblotting analysis was used to detect the expression of cyclin D1 and CDK4. Immunofluorescence staining assay was performed to detect the expression of the DNA injury marker ץ-H2AX after treatment with rucaparib and radiotherapy. Animal experiments were also performed to evaluate tumor size after treatment with rucaparib. Immunohistochemistry was performed to analyze the expression of Ki-67. Results Rucaparib suppressed proliferation, induced G2/M phase arrest, and reduced the expression of cyclin D1 and CDK4 in cervical cancer cells. When rucaparib was combined with radiotherapy in cervical cancer cells, clone formation decreased significantly and G2/M phase arrest was accentuated. The expression of the DNA-damage marker ץ-H2AX was increased significantly, and rucaparib suppressed tumor growth in vivo. Conclusions Rucaparib exerts significant anti-proliferative effects and can serve as an effective radiosensitizer in cervical cancer, suggesting its candidacy in cervical cancer treatment and worthiness for further investigation.

The overexpression of PXN promotes tumor progression and leads to radioresistance in cervical cancer

AIM We aim to investigate the functions of PXN in cervical cancer. MATERIALS & METHODS PXN protein was investigated by immunohistochemistry in a panel of cervical cancer. A series of in vitro and in vivo assays were used to explore the efficacy of PXN. RESULTS PXN was significantly upregulated in cervical cancer, which associated with tumor stage, poor differentiation, lymphovascular space invasion and lymphatic metastasis. Knockdown of PXN notably impaired cellular growth and colony formation by suppressing Bcl-2 and inducing marked apoptosis. Moreover, PXN led to resistance to radiation, and downregulation of PXN resensitized C33A cells to radiation. CONCLUSION PXN was frequently upregulated and acted as an oncogene via regulating Bcl-2 in cervical cancer, which supports PXN as a potent therapeutic target.

Buformin suppresses proliferation and invasion via AMPK/S6 pathway in cervical cancer and synergizes with paclitaxel

ABSTRACT Buformin is an old anti-diabetic agent and manifests potent anti-tumor activities in several malignancies. In the present study, we aimed to explore the functions of buformin in human cervical cancer. As our data shown, buformin exhibited significant anti-proliferative effects in a dose-dependent manner in 4 cervical cancer cell lines. Compared to the control, buformin notably suppressed colony formation and increased ROS production in C33A, Hcc94 and SiHa cells. Flow cytometric analysis showed that buformin induced marked cell cycle arrest but only resulted in mild apoptosis. The invasion of C33A and SiHa cells sharply declined with buformin treatment. Consistently, western blotting showed that buformin activated AMPK and suppressed S6, cyclin D1, CDK4, and MMP9. Moreover, we found that buformin enhanced glucose uptake and LDH activity, increased lactate level, while decreased ATP production in cervical cancer cells. In addition, low doses of buformin synergized with routine chemotherapeutic drugs (such as paclitaxel, cisplatin, and 5-FU) to achieve more significant anti-tumor effects. In vivo, a single use of buformin exerted moderate anti-tumor effects, and the combination with buformin and paclitaxel exhibited even greater suppressive effects. Buformin also consistently showed synergistic effects with paclitaxel in treating primary cultures of cervical cancer cells. Take together, we are the first to demonstrate that buformin suppresses cellular proliferation and invasion through the AMPK/S6 signaling pathway, which arrests cell cycle and inhibits cellular invasion. Buformin also could synergize with routine chemotherapies, producing much more powerful anti-tumor effects. With these findings, we strongly support buformin as a potent choice for treating cervical cancer, especially in combination with routine chemotherapy.