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Background The incidence of thyroid cancer, a most common tumor in the endocrine system, has increased in recent years. A growing number of studies have focused on the molecular mechanisms of thyroid cancer subtypes, aiming to identify effective therapeutic targets. Endocytosis is of vital significance in the malignant development of tumors, although its involvement in thyroid cancer has been rarely reported. Methods HIP1R expressions in thyroid cancer from the TCGA database were analyzed by UALCAN software. Thyroid epithelial and cancer cell lines were cultured in vitro. Western blotting and quantitative PCR were used to analyze protein and mRNA levels, respectively. Cell viability was measured by CCK-8 assay. Immunofluorescence staining indicated protein distribution in cell. Co-immunoprecipitation was used to study protein–protein interaction. Immunohistochemical staining was used to analyze protein expression in clinical tissues. Differences between groups were compared using the two-tailed Student’s t test, and those among three or more groups were compared by one-way or two-way ANOVA. Results In the present study, HIP1R (Huntingtin Interacting Protein 1 Related) was found upregulated in thyroid cancer tissues and cell lines compared with that in the controls, while knockdown of HIP1R significantly inhibited the proliferation of thyroid cancer cells. Since HIP1R is essential for the clathrin-dependent endocytic process, we thereafter explored the effect of HIP1R on the endocytosis of thyroid cancer cells. Interestingly, knockdown of HIP1R significantly reduced the number of clathrin-coated pits (CCPs) in thyroid cancer cells. In addition, the interaction between HIP1R and PTEN (phosphatase and tensin homolog) was identified in thyroid cancer cells. Knockdown of HIP1R downregulated intracellular PTEN in thyroid cancer cells, but upregulated membrane-binding PTEN. Notably, flurbiprofen, a commonly used analgesic, significantly inhibited the proliferation of thyroid cancer cells and interfered with the interaction between HIP1R and PTEN, thereby enhancing the binding of PTEN to cell membrane. However, the proliferation inhibitory effect of flurbiprofen was attenuated when knocking down HIP1R or PTEN. Conclusions Upregulated HIP1R in thyroid cancer cells promotes cell proliferation and mediates the endocytosis of PTEN. Flurbiprofen may exert an anti-tumor effect on thyroid cancer by blocking the interaction between HIP1R and PTEN.

MicroRNA (miR)-199a-5p expression is downregulated in a variety of malignancies, including non-small cell lung cancer (NSCLC), and its low expression is associated with a poor prognosis. However, to the best of our knowledge, the mechanism underlying miR-199a-5p downregulation in NSCLC and its target effectors remain to be elucidated. The present study revealed the downregulation of miR-199a-5p expression in NSCLC tissues and cell lines compared with in para-carcinoma tissues and a lung epithelial cell line. Further experiments indicated that the methylation levels of the miR-199a promoter were markedly higher in NSCLC tissues compared with in para-carcinoma tissues. The DNA methyltransferase inhibitor 5-Aza-2'-deoxycytidine markedly increased the expression levels of miR-199a-5p in NSCLC cells. Furthermore, it was identified that miR-199a-5p mimics transfection decreased the expression levels of A-kinase anchoring protein 1 (AKAP1) at both the mRNA and protein levels by targeting the 3' untranslated region of AKAP1 mRNA. The in vitro experiments demonstrated that miR-199a-5p overexpression inhibited the proliferation and tumorigenicity of NSCLC cells, whereas overexpression of AKAP1 partially recovered the malignant phenotypes, suggesting that AKAP1 may be a downstream effector targeted by miR-199a-5p. Collectively, the present findings indicated that miR-199a-5p may be a novel regulator of AKAP1, and that miR-199a-5p may be a potential tumor suppressor in NSCLC.

The present study aimed to investigate the potential role of microRNA‑448 (miR‑448) in isoflurane-induced learning and memory impairment in rats. Sprague‑Dawley rats were used for the construction of isoflurane‑treated models. The Morris water maze test was used to evaluate the effects of isoflurane on rats regarding the following para-meters: Swimming speed, escape latency and time in original quadrant. Influences of isoflurane on neuron apoptosis and miR‑448 expression in rat hippocampus tissue were analyzed by flow cytometry and reverse transcription‑quantitative polymerase chain reaction, respectively. Furthermore, the effects of miR‑448 on the expression of cell apoptosis‑associated proteins were investigated by flow cytometry. The results demonstrated that isoflurane treatment induced higher escape latency and lower time spent in original quadrant compared with the control rats. In addition, isoflurane treatment induced neuron apoptosis and miR‑448 was highly expressed in the hippocampal tissue of isoflurane‑treated rats. Furthermore, Bcl‑x was significantly downregulated while caspase‑3 expression was upregulated by an miR‑448 inhibitor. Combined the results of the current study indicate that miR‑448 knockdown may have pivotal roles in improving isoflurane-induced learning and memory impairment via suppressing neuron apoptosis.

Cisplatin-based therapy is one of the most important chemotherapy treatments for cancers. However, its efficacy is greatly limited by drug resistance and undesirable side effects. Therefore, it is of great importance to develop effective chemosensitization agents to cisplatin. In the present study, we demonstrated the strategy to use shikonin, a natural product from the root of Lithospermum erythrorhizon, as a synergistic agent of cisplatin and elucidated their action mechanisms. The combination of shikonin and cisplatin exhibited synergistic anticancer efficacy and achieved greater selectivity between cancer cells and normal cells. By inducing intracellular oxidative stress, shikonin potentiated cisplatin-induced DNA damage, followed by increased activation of mitochondrial pathway. In addition, inhibition of ROS reversed the apoptosis induced by shikonin and cisplatin, and recovered the depletion of mitochondrial membrane potential, which revealed the vital role of ROS in the synergism. Moreover, HCT116 xenograft tumor growth in nude mice was more effectively inhibited by combined treatment with shikonin and cisplatin. Our findings suggest that the strategy to apply shikonin as a synergistic agent to cisplatin could be a highly efficient way to achieve anticancer synergism by inducing intracellular oxidative stress. Shikonin may be a promising candidate as a chemosensitizer to cisplatin-based therapy for cancer treatments.

Inhibitor of DNA binding/differentiation 2 (Id2) belongs to a helix-loop-helix family of proteins. Recent studies have showed that Id2 plays a pivotal role in neuronal survival and neuroprotection. However, under neuropathic pain conditions, the role of Id2 is still unclear. In this study, we investigated the effect of Id2 on neuropathic pain in a rat chronic constriction injury (CCI) model. Our results demonstrated that Id2 was upregulated in the dorsal root ganglion (DRG) in a CCI rat in a time-dependent manner. Intrathecal short-hairpin RNA (shRNA)-Id2 attenuates mechanical allodynia and thermal hyperalgesia in CCI rats, and inhibits the expression of TNF-α and IL-1β in the DRG in CCI rats. Furthermore, knockdown of Id2 reduces the expression of NF-κB p65 in the DRG of CCI rats. Taken together, our findings suggest that knockdown of Id2 may alleviate neuropathic pain by inhibiting the NF-κB activation to inhibit the production of pro-inflammatory mediators. Therefore, Id2 may provide an important target of neuropathic pain treatment.