Circular RNA (circRNA) is a novel subclass of noncoding-RNA molecules that participate in development and progression of a variety of human diseases via sponging microRNAs (miRNAs). Until now, the contributions of circRNAs in chemoresistance of hepatocellular carcinoma (HCC) remain largely unknown.In the present study, we aimed to investigate the role of circRNA in cisplatin resistance of HCC. We investigated the expression of circRNAs in 5 paired cisplatin-sensitive and cisplatin-resistant HCC tissues by microarray analysis. The qRT-PCR analysis was to investigate the expression pattern of circARNT2 in HCC patient tissues and cell lines. Then, the effects of circARNT2 on cisplatin resistance, cell proliferation, and apoptosis were assessed in HCC in vitro and in vivo. cir-cARNT2 was significantly upregulated in HCC tissues and cell lines. Overexpression of circARNT2 in HCC was significantly correlated with aggressive characteristics and served as an independent risk factor for overall survival in patients with HCC. In vitro experiments showed that knockdown of cir-cARNT2 inhibited cell proliferation and enhances the cisplatin sensitivity of HCC cells. Furthermore, circARNT2 facilitates HCC progression in vivo. We demonstrated that circARNT2 acts as a sponge for miR-155-5p and verified that PDK1 is a novel target of miR-155-5p. In summary, our study demonstrated that circARNT2 modulates cisplatin resistance through miR-155-5p/PDK1 pathway. Our findings indicated that cir-cARNT2 may serve as a promising therapeutic target for overcoming cisplatin resistance for HCC.

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Glioblastoma has been identified as the most common and aggressive primary brain tumor in adults. Recently, it has been found that cisplatin (DDP) treatment is a common chemotherapeutic method for GBM patients. circ_PTN (ID number: hsa_circ_0003949) is a newly found circular (circRNA) which has been proved to be highly expressed in GBM cells, while its role in GBM remains unclear. Therefore, our study focused on investigating the role of circ_PTN in the DDP resistance of GBM cells. The expression of circ_PTN in DDP-sensitive and DDP-resistant GBM cells was detected in our assay. Functional experiments were utilized to unveil the effects of circ_PTN on the DDP resistance of GBM cells. Moreover, mechanism assays were conducted to confirm the mechanism of how circ_PTN affected the DDP resistance of GBM cells. According to the results, we found that circ_PTN promoted the DDP resistance of GBM cells through activation of the PI3K/AKT pathway. Moreover, circ_PTN silencing inhibited the DDP resistance of GBM tumors in vivo . To conclude, our study unveiled the influence of circ_PTN on the DDP resistance of GBM cells, which might provide a therapeutic target for GBM treatment via DDP.

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Accurately and quickly differentiating true progression from pseudoprogression in glioma patients is still a challenge. This study aims to explore if dynamic susceptibility contrast- (DSC-) MRI can improve the evaluation of glioma progression. We enrolled 65 glioma patients with suspected gadolinium-enhancing lesion. Longitudinal MRI follow-up (mean 590 days, range: 210–2670 days) or re-operation (n = 3) was used to confirm true progression (n = 51) and pseudoprogression (n = 14). We assessed the diagnostic performance of each MRI variable and the different combinations. Our results showed that the relative cerebral blood volume (rCBV) in the true progression group (1.094, 95%CI: 1.135–1.636) was significantly higher than that of the pseudoprogression group (0.541 ± 0.154) p < 0.001 . Among the 18 patients who had serial DSC-MRI, the rCBV of the progression group (0.480, 95%CI: 0.173–0.810) differed significantly from pseudoprogression (-0.083, 95%CI: −1.138–0.620) group p = 0.015 . With an rCBV threshold of 0.743, the sensitivity and specificity for discriminating true progression from pseudoprogression were 76.5% and 92.9%, respectively. The Cho/Cr and Cho/NAA ratios of the true progression group (2.520, 95%CI: 2.331–2.773; 2.414 ± 0.665, respectively) were higher than those of the pseudoprogression group (1.719 ± 0.664; 1.499 ± 0.500, respectively) ( p = 0.001 , p < 0.001 , respectively). The areas under ROC curve (AUCs) of enhancement pattern, MRS, and DSC-MRI for the differentiation were 0.782, 0.881, and 0.912, respectively. Interestingly, when combined enhancement pattern, MRS, and DSC-MRI variables, the AUC was 0.965 and achieved sensitivity 90.2% and specificity 100.0%. Our results suggest that DSC-MRI can significantly improve the diagnostic performance for identifying glioma progression. DSC-MRI combined with conventional MRI may promptly distinguish true gliomas progression from pseudoprogression when the suspected gadolinium-enhancing lesion was found, without the need for a long-term follow-up.