Mechanism Study Of Formononetin In The Treatment Of Oxaliplatin-induced Peripheral Neuropathy

Oxaliplatin(OHP),a platinum-based chemotherapeutic agent,is used as the standard of care treatment for metastatic colorectal cancer.However,Oxaliplatin-induced peripheral neuropathy(OIPN)severely affects the chemotherapy regimen and quality of survival of patients with tumors.More than 80%of patients with colorectal cancer who receive an oxaliplatin-associated chemotherapy regimen have induced lesions that damage the peripheral nerve,with the impairment potentially being permanent.Current drugs for the treatment of OIPN have problems of significant toxic side effects and insignificant clinical efficacy,while drugs under development that have also achieved efficacy in animal trials have not achieved the expected efficacy in large-scale clinical trials.Effective treatment options for OIPN are still lacking in the clinic.OIPN often presents with numbness,pain or abnormal sensation in the limbs,weakness,tingling,etc.,which is particularly consistent with the description of "blood paralysis" in Chinese medicine.Huangqi Guizhi decoction is the counterpart of the treatment of blood paralysis in the<golden chamber synopsis>.Scholars have found that Huangqi Guizhi decoction can reduce the incidence of oxytocin neurotoxicity,and they have tentatively elucidated the mechanism of action of the formula on chemotherapy-induced peripheral neurotoxicity associated with oxidative stress modulating factor Nrf2 and pain ion channel protein.In the present study,it was found that the main active ingredient of Huangqi Guizhi decoction,formononetin(FN),effectively activated the Nrf2-ARE signaling pathway and reversed oxaliplatin-induced neurotoxicity.RNA interference experiments revealed that formononetin protects against OIPN directly through activation of the Nrf2 pathway.Further expression profile sequencing showed that formononetin exerts its protective effect via the Nrf2 downstream-oxaliplatin metabolism enzyme Gstp1.We also demonstrated that formononetin does not influence the chemotherapeutic function of oxaliplatin,as Nrf2 exhibits a different drug metabolic enzyme activation state downstream in colorectal cell lines than that in neurons.Following synthesis of Bio-FN to screen the target binding proteins,we found that formononetin selectively bound His129 and Lys131 in the BTB domain of Keapl protein,whereas modification in the B ring of formononetin might destroy the binding interaction with Keap1.In vivo experiments revealed that FN-induced activation of the Nrf2 signaling pathway alleviated the nociceptive sensations in mice.Together,our findings highlight a new binding mechanism between Keapl and isoflavones for activation of the Nrf2 system,and suggest that pharmacological or therapeutic activation of the Nrf2-Gstp1 axis may serve as an effective strategy to prevent or attenuate the progression of OIPN.Innovative outcome obtained in this study:1.Formononetin protects against oxaliplatin-induced peripheral neuropathy.2.Formononetin exerts its protective effects via the Nrf2-GSTpi pathway.3.Formononetin selectively retains oxaliplatin cytotoxicity by triggering different Nrf2 downstream activation states in neurons vs.colorectal cancer cells.4.Formononetin selectively binds His129 and Lys131 in the Keapl BTB domain.5.B but not A ring modification may impede Nrf2 activation by Formononetin?...