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Epithelial ovarian cancer has the highest mortality rate of all malignant ovarian cancer types. Great progress has been made in the treatment of ovarian cancer in recent years. However, drug resistance has led to a low level of 5-year survival rate of epithelial ovarian cancer, and the molecular mechanism of which remains unknown. The aim of the present study was to identify the role of redox status in the cisplatin (CDDP) resistance of ovarian cancer. CDDP-resistant SK-OV3 (SK-OV3/cddp) cells were prepared and their reactive oxygen species and glutathione levels were investigated. The effects of hydrogen peroxide on the CDDP sensitivity of the SK-OV3/cddp cells and their expression levels of the redox-associated protein growth arrest and DNA damage 45a (GADD45α) were also investigated. In addition, the impact of GADD45α overexpression on cell viability was evaluated in vitro and in vivo, and the levels of Ser-139 phosphorylated H2A histone family member X (γ-H2AX), which is associated with DNA damage, were detected. The results suggested that redox status affected the drug resistance of the ovarian cancer cells by increasing the expression of GADD45α. The overexpression of GADD45α reversed the CDDP resistance of the SK-OV3/cddp cells and increased the level of γ-H2AX. In conclusion, GADD45α alleviated the CDDP resistance of SK-OV3/cddp cells via the induction of redox-mediated DNA damage.

Colorectal cancer (CRC) is the third most common cancer worldwide and its treatment remains a challenge. Effective control of cell survival and proliferation is critical in the prevention of oncogenesis and successful treatment of cancer. Long non-coding RNAs (lncRNAs) have emerged as primary regulators of carcinogenesis. Growth arrest specific 5 (GAS5), a lncRNA, is known to be aberrantly expressed in several types of cancer, however, the role of GAS5 in CRC remains unclear. In the present study, GAS5 mRNA expression was measured in CRC and adjacent normal mucosa tissue samples from 53 patients using reverse transcription-quantitative polymerase chain reaction analysis, in addition to seven CRC cell lines. GAS5 mRNA expression was observed to be markedly downregulated in human CRC tissues and cell lines. Decreased GAS5 expression was associated with an increase in tumor diameter [odds ratio (OR), 0.176 (95% CI, 0.053–0.586); P=0.003] and later tumor-node-metastasis stage [OR, 0.261 (95% CI, 0.083–0.819); P=0.019]. Patients with decreased GAS5 expression exhibited decreased overall survival rates compared with patients with increased GAS5 expression (P=0.015). The Cox proportional hazards model demonstrated that downregulated GAS5 expression was an independent prognostic factor for CRC (hazard ratio, 0.236; 95% confidence interval, 0.067–0.827; P=0.024). Functional assays demonstrated that overexpression of GAS5 inhibited cell proliferation and survival, and induced G0/G1 cell cycle arrest and apoptosis; however, knockdown of GAS5 expression enhanced cell proliferation, and reduced G0/G1 arrest and apoptosis. In conclusion, the results of the present study suggest that GAS5 is essential in the control of apoptosis and cell growth in CRC. Therefore, GAS5 may represent a novel prognostic and diagnostic marker of CRC, in addition to being a potential therapeutic target.

Hepatic transcatheter arterial chemoembolization (TACE), a minimally invasive procedure to block the blood supply of tumors and release of cytotoxic agents, is preferentially applied to patients with hepatocellular carcinoma (HCC) who are not able to receive radical treatments. However, the long-term effects of TACE are unsatisfactory, as the microenvironment following procedure stimulates tumor angiogenesis, which promotes recurrence and metastasis of residual tumors. Tumor associated macrophages (TAMs) have been revealed to stimulate tumor growth and angiogenesis associated with poor prognosis in HCC. The present study focused on the changes in TAMs following TACE, and explored the effects of TACE in combination with the TAM inhibitor zoledronic acid (ZA) in rat HCC models. Orthotropic HCC rats were divided into three groups: Sham TACE, TACE alone and TACE combined with ZA treatment. At 7 or 14 days following TACE, tumor growth was evaluated by magnetic resonance imaging (MRI). Infiltration of TAMs was assessed by histological analysis and flow cytometry. Tumor angiogenesis was measured as the mean vessel density, and initial slope was calculated from dynamic contrast enhancement MRI. Local and systemic levels of vascular endothelial growth factor (VEGF) were determined by western blotting or an ELISA, respectively. The results revealed that TACE inhibited tumor growth at 7 days following the procedure, but this inhibition was attenuated at 14 days following the procedure compared with the sham TACE control. If combined with ZA treatment, TACE exhibited a stable inhibition effect on tumor growth until the end of observation. Investigation of the underlying mechanisms demonstrated that TACE combined with ZA treatment inhibited infiltration of F4/80 positive TAMs and tumor angiogenesis compared with the TACE alone group at 14 days following the procedure. Additionally, the combination treatment significantly inhibited secretion of VEGF in the present models. In conclusion, ZA treatment enhanced the effects of TACE through inhibiting TAM infiltration and tumor angiogenesis in rat HCC models.

[This retracts the article DOI: 10.3892/ol.2018.7769.]., (Copyright: © Jiang et al.)

[This corrects the article DOI: 10.3892/ol.2018.7764.]., (Copyright: © Zhu et al.)