Over-expression of miR-3584-5p Represses Nav1.8 Channel Aggravating Neuropathic Pain caused by Chronic Constriction Injury.

Nav1.8, a tetrodotoxin-resistant voltage-gated sodium channels (VGSCs) subtype encoded by SCN10A, which plays an important role in the production and transmission of peripheral neuropathic pain signals. Studies have shown that VGSCs may be key targets of MicroRNAs (miRNAs) in the regulation of neuropathic pain. In our study, bioinformatics analysis showed that the targeting relationship between miR-3584-5p and Nav1.8 was the most closely. The purpose of this study was to investigate the roles of miR-3584-5p and Nav1.8 in neuropathic pain. The effects of miR-3584-5p on chronic constriction injury (CCI)-induced neuropathic pain in rats was investigated by intrathecal injection of miR-3584-5p agomir (an agonist, 20 µM, 15 µL) or antagomir (an antagonist, 20 µM, 15 µL). The results showed that over-expression of miR-3584-5p aggravated neuronal injury by hematoxylin-eosin (H&E) staining and mechanical/thermal hypersensitivity in CCI rats. MiR-3584-5p indirectly inhibited the expression of Nav1.8 by up-regulating the expression of key proteins in the ERK5/CREB signaling pathway, and also inhibited the current density of the Nav1.8 channel, changed its channel dynamics characteristic, thereby accelerating the transmission of pain signals, and further aggravating pain. Similarly, in PC12 and SH-SY5Y cell cultures, miR-3584-5p increased the level of reactive oxygen species (ROS) and inhibited mitochondrial membrane potential (Δψm) in the mitochondrial pathway, decreased the ratio of apoptosis-related factor Bcl-2/Bax, and thus promoted neuronal apoptosis. In brief, over-expression of miR-3584-5p aggravates neuropathic pain by directly inhibiting the current density of Nav1.8 channel and altering its channel dynamics, or indirectly inhibiting Nav1.8 expression through ERK5/CREB pathway, and promoting apoptosis through mitochondrial pathway.

Effect of Apatinib Plus Pegylated Liposomal Doxorubicin vs Pegylated Liposomal Doxorubicin Alone on Platinum-Resistant Recurrent Ovarian Cancer: The APPROVE Randomized Clinical Trial.

Importance: There are substantial unmet therapeutic needs in patients with platinum-resistant recurrent ovarian cancer (PROC), and novel therapeutic strategies should be explored. Objective: To evaluate the efficacy and safety of treatment with apatinib (a vascular endothelial growth factor receptor 2 tyrosine kinase inhibitor) plus pegylated liposomal doxorubicin (PLD) for PROC. Design, Setting, and Participants: The APPROVE trial was performed as an open-label, randomized clinical trial at 11 hospitals in China between March 22, 2018, and November 16, 2020. Patients with histologically confirmed ovarian cancer who had experienced disease progression during or within 6 months of discontinuing any prior line of treatment with platinum-based chemotherapy were eligible. This primary analysis was based on data that were current as of January 28, 2021. Interventions: Patients received PLD alone (40 mg/m2, intravenously, every 4 weeks, for up to 6 cycles) or PLD plus apatinib (250 mg, orally, daily). Main Outcomes and Measures: The primary end point was progression-free survival (PFS) by Response Evaluation Criteria in Solid Tumours (RECIST), version 1.1, in the intent-to-treat population. Results: In total, 152 female patients were randomized, with 78 (51.3%) in the apatinib plus PLD group (median age, 54 years; range, 22-76 years) and 74 (48.7%) in the PLD group (median age, 56 years; range, 33-72 years). The median follow-up duration was 8.7 months (IQR, 4.7-14.1 months). The median PFS was 5.8 months (95% CI, 3.8-8.8) for treatment with apatinib plus PLD vs 3.3 months (95% CI, 2.1-3.8) for PLD (hazard ratio, 0.44; 95% CI, 0.28-0.71; P < .001). The median overall survival was 23.0 months (95% CI, 18.9 to not reached) with treatment with apatinib plus PLD vs 14.4 months (95% CI, 12.1-23.4) with PLD (hazard ratio, 0.66; 95% CI, 0.40-1.09). The most frequent grade 3 or higher treatment-emergent adverse events were decreased neutrophil counts (11 [14.9%] in the apatinib plus PLD group vs 6 [8.3%] in the PLD group), hypertension (6 [8.1%] vs none), and decreased white blood cell count (5 [6.8%] vs 3 [4.2%]). Two patients receiving treatment with apatinib plus PLD experienced grade 2 fistulas. Conclusions and Relevance: This randomized clinical trial found that treatment with apatinib plus PLD showed promising efficacy and manageable toxic effects in patients with PROC and may be a new alternative treatment option in this setting. Trial Registration: Clinicaltrials.gov Identifier: NCT04348032.

Positive shift of Nav1.8 current inactivation curve in injured neurons causes neuropathic pain following chronic constriction injury.

Neuropathic pain is a global medical concern, characterized by spontaneous pain, heat hyperalgesia and mechanical allodynia. The condition has been associated with alterations in the voltage­gated sodium channels, Nav1.8 and Nav1.9, in nociceptive neurons termed nociceptors. However, an explanation for the contribution of these channels to the phenotype observed in neuropathic pain remains to be elucidated. The changes induced by chronic constriction injury (CCI) to Nav1.8 and Nav1.9 mRNA and protein levels, as well as electrical currents in injured and contralateral non­injured dorsal root ganglion (DRG) neurons are described in the present study. A marked downregulation was observed for each Nav isoform transcript and protein expressed in injured neurons with the exception of the Nav1.9 protein, which exhibited no change, while in contralateral non­injured neurons, the levels of protein and mRNA remained unchanged. Nav isoform functional analysis was then performed in L(4­6) DRG neurons 14 days after CCI. The Nav1.8 current density was markedly decreased in injured DRG neurons following CCI. The voltage­dependent activation of the Nav1.8 channel in these neurons was shifted to depolarized potentials by 5.3 mV, while it was shifted to hyperpolarized potentials by 10 mV for inactivation. The electrophysiological function of Nav1.9 was not affected by CCI. The present study demonstrated that ectopic discharge following CCI, which was likely induced by a positive shift in the Nav1.8 current inactivation curve in injured neurons, enhanced the excitability of the neurons by facilitating tetrodotoxin­resistant sodium channels into the fast inactivation state and did not occur as a result of a compensatory redistribution in the contralateral uninjured neurons.