Quercetin-targeted AKT1 regulates the Raf/MEK/ERK signaling pathway to protect against doxorubicin-induced nephropathy in mice

BACKGROUND

Doxorubicin is an anthracycline antitumor agent commonly used in clinical practice, which has some nephrotoxicity and is often used to establish mouse models of kidney injury for basic medical research. This study will investigate the protective effect of quercetin on renal function in doxorubicin-induced nephropathy mice.

METHODS

C57BL/6 mice were divided into control, model, and quercetin low-, and high-dose groups. Serum and urine were collected to analyze markers of kidney function. H&E staining was used to detect pathological changes in renal tissues. Transmission electron microscopy was performed to observe the ultrastructural changes in renal tissues. Immunohistochemistry was performed to detect the changes of Ang II. RT-qPCR was performed to detect the changes of cytokines. ELISA was used to detect changes in serum inflammatory factors. Molecular docking was performed to verify the targeting relationship between quercetin and AKT1. Western blot was performed to detect Bax, Bcl-2, Cyt-c, AKT1, Raf, MEK, and ERK proteins.

RESULTS

Quercetin could induce the recovery of kidney function in kidney-injured mice; H&E results showed that kidney tissue damage and tissue fibrosis were reduced in kidney-injured mice under quercetin. The mitochondrial swollen structure was destroyed by doxorubicin, while the mitochondrial structure was restored under quercetin. The levels of abnormal apoptotic proteins Bax and Bcl-2 were regulated to normal by quercetin. The high expression of Ang II caused by doxorubicin was down-regulated by quercetin. Abnormal inflammatory factors caused by doxorubicin were reversed by quercetin. Western blot experiments showed that quercetin regulated the protein levels of AKT1 and Raf/MEK/ERK and inhibited the detrimental effects of doxorubicin.

CONCLUSION

Quercetin may mitigate doxorubicin-induced kidney injury in mice by regulating renal cell inflammatory factors and Raf/MEK/ERK signaling pathway through AKT1 to promote recovery of renal function.

Effect of electroacupuncture on urodynamics and Raf/MEK/ERK signaling pathway in spinal cord tissue of rats with detrusor hyperreflexia after suprasacral spinal cord injury

OBJECTIVES

To observe the effect of electroacupuncture (EA) on urodynamics and Raf/MEK/ERK signaling pathway in spine cord tissue of rats after suprasacral spinal cord injury (SSCI), so as to explore its possible mechanism in improving bladder function in rats with detrusor hyperreflexia after SSCI.

METHODS

Female SD rats were randomly divided into blank, sham operation, model, EA and EA+PD98059 groups, with 12 rats in each group. Thorax (T) 10 spinal cord transection was performed by surgery. Rats in the EA group were given EA (10 Hz/50 Hz, 20 min) at "Ciliao" (BL32), "Zhongji" (CV3), "Sanyinjiao" (SP6) and "Dazhui" (GV14) once daily for 7 d. Rats of the EA+PD98059 group received intraperitoneal injection of PD98059 (5 mg/kg) 2 h before EA intervention. The urodyna-mics was used to measure the base pressure, leak point pressure, maximum pressure, maximum capacity and comp-liance of bladder, and the morphology of bladder detrusor tissue was observed with HE staining. The TUNEL staining was used to detect the cell apoptosis of the spinal cord tissue. The expression levels of exchange protein directly activated by cAMP 2 (Epac2), Rap, phosphorylated rapidly accelerated fibrosarcoma (p-Raf), phosphorylated mitogen-activated extracellular signal-regulated kinase (p-MEK), phosphorylated extracellular signal regulated kinase 1 and 2 (p-ERK1/2), B-cell lymphoma-2 (Bcl-2), and Bcl-2 associated X protein (Bax) were determined by Western blot.

RESULTS

Compared with the sham operation group, the base pressure, leak point pressure and maximum pressure of bladder were significantly increased (P<0.01), the maximum bladder capacity and bladder compliance were decreased (P<0.01), the cell apoptosis rate of spinal cord tissue was increased (P<0.01), and the expression levels of Epac2, Rap, p-Raf, p-MEK, p-ERK1/2, and Bcl-2 protein in spinal cord tissue were decreased (P<0.01), while the expression level of Bax protein was increased (P<0.01) in the model group. After the treatment and compared with the model group, the base pressure, leak point pressure and maximum pressure of bladder, the cell apoptosis rate of spinal cord tissue, the expression level of Bax protein were decreased (P<0.05) in the EA group, while the maximum bladder capacity and bladder compliance, the expression levels of Epac2, Rap, p-Raf, p-MEK, p-ERK1/2, and Bcl-2 protein in spinal cord tissue were all increased (P<0.05, P<0.01). In comparison with the EA group, the base pressure, leak point pressure and maximum pressure of bladder, the cell apoptosis rate, the expression level of Bax protein were significantly increased (P<0.05), whereas the maximum bladder capacity, bladder compliance, and the expression levels of p-MEK, p-ERK1/2, and Bcl-2 protein were decreased (P<0.05) in the EA+PD98059 group. Results of HE staining showed disordered transitional epithelial cells and destroyed lamina propria in bladder detrusor tissue, with the infiltration of monocytes in the model group, which was obviously milder in both EA and EA+PD98059 groups, especially in the EA group.

CONCLUSIONS

EA can improve the bladder function in detrusor hyperreflexia rats after SSCI, which may be related to its effect in up-regulating Epac2 and Rap, activating the Raf-MEK-ERK pathway, and reducing the cell apoptosis of spinal cord tissue.

Preclinical evaluation of Mito-LND, a targeting mitochondrial metabolism inhibitor, for glioblastoma treatment

BACKGROUND

Glioblastoma (GBM) is a brain tumor with the highest level of malignancy and the worst prognosis in the central nervous system. Mitochondrial metabolism plays a vital role in the occurrence and development of cancer, which provides critical substances to support tumor anabolism. Mito-LND is a novel small-molecule inhibitor that can selectively inhibit the energy metabolism of tumor cells. However, the therapeutic effect of Mito-LND on GBM remains unclear.

METHODS

The present study evaluated the inhibitory effect of Mito-LND on the growth of GBM cells and elucidated its potential mechanism.

RESULTS

The results showed that Mito-LND could inhibit the survival, proliferation and colony formation of GBM cells. Moreover, Mito-LND induced cell cycle arrest and apoptosis. Mechanistically, Mito-LND inhibited the activity of mitochondrial respiratory chain complex I and reduced mitochondrial membrane potential, thus promoting ROS generation. Importantly, Mito-LND could inhibit the malignant proliferation of GBM by blocking the Raf/MEK/ERK signaling pathway. In vivo experiments showed that Mito-LND inhibited the growth of GBM xenografts in mice and significantly prolonged the survival time of tumor-bearing mice.

CONCLUSION

Taken together, the current findings support that targeting mitochondrial metabolism may be as a potential and promising strategy for GBM therapy, which will lay the theoretical foundation for further clinical trials on Mito-LND in the future.

Long non‑coding RNA BANCR promotes proliferation, invasion and migration in esophageal squamous cell carcinoma cells via the Raf/MEK/ERK signaling pathway

Esophageal squamous cell carcinoma (ESCC) is a major histological type of esophageal cancer, identified as a leading cause of tumor-associated death worldwide. In addition, long non-coding RNA (lncRNA) BRAF-activated non-coding RNA (BANCR) expression is increased in the plasma of patients with ESCC, which can be reversed by tumor resection. Thus, the aim of the present study was to investigate the underlying mechanism of BANCR in ESCC progression. The relative mRNA expression of BANCR was determined via reverse transcription-quantitative PCR. The cell behaviors of Eca-109 cells were detected using Cell Counting Kit-8, colony formation, wound healing and Transwell chamber assays. Finally, the expression levels of proteins involved in the Raf/MEK/ERK signaling pathway and cell metastasis were analyzed with western blotting. The results revealed that lncRNA BANCR was highly expressed in ESCC cells compared with in normal esophageal cells. BANCR overexpression enhanced proliferation, migration and invasion of ESCC cells, and BANCR silencing exerted opposite effects. Moreover, BANCR overexpression induced activation of the Raf/MEK/ERK signaling pathway in ESCC cells. Notably, U0126, a specific MEK inhibitor, decreased MEK and ERK expression, and blocked the promotive effects of BANCR overexpression on the proliferation, migration and invasion of ESCC cells. Overall, lncRNA BANCR facilitated the proliferation, migration and invasion of ESCC cells via the Raf/MEK/ERK signaling pathway. Thus, lncRNA BANCR may be a promising target for inhibiting ESCC growth and metastasis.

SOX9 was involved in TKIs resistance in renal cell carcinoma via Raf/MEK/ERK signaling pathway

Renal cell carcinoma (RCC) is common genitourinary malignancy in human, 30-40% of patients with RCC would be diagnosed with metastatic RCC (mRCC). Even in the era of targeted therapy, patients with mRCC would inevitably progress due to drug resistance. Herein, exploration of the mechanisms of resistance is noteworthy to study. In the present study, we firstly reported the expression profile of SOX9 in renal carcinoma cells and tissues, and found that its expression was significantly associated with Fuhrman grading. Dual luciferase analysis confirmed that Raf/MEK/ERK pathway could directly be regulated by SOX9, and sequential experiments demonstrated that, renal carcinoma cells could sensitize to Sorafenib/Sunitinib through Raf/MEK/ERK signaling pathway inhibition regulated by SOX9 down-regulation. In a small cases with mRCC treated with Sorafenib/Sunitinib (n=38), comparative analysis showed that patients with SOX9 (-) had much better therapeutic response to TKIs than those with SOX9 (+) (PD: 9.1% vs. 56.2%, P=0.002, DCR: 90.9% vs. 43.8%, P=0.002). Based on these findings, we concluded that, SOX9 was firstly described to be highly expressed in renal cell carcinoma, and its expression was involved in TKIs drug resistance through activation of Raf/MEK/ERK pathway. In vitro, patients with SOX9 (-) was related to better response to TKIs treatment than those with SOX9 (+). SOX9 could be expected to be a promising biomarker predicting TKIs response and even expected to be another novel target in the treatment of mRCC.