Therapeutic Potential of BMX-001 for Preventing Chemotherapy-Induced Peripheral Neuropathic Pain

Abstract

Background/Objectives: Chemotherapy-induced neuropathic pain (CINP) represents a critical challenge in oncology, emerging as a common and debilitating side effect of widely used chemotherapeutic agents, such as paclitaxel (PTX). Current therapeutic interventions and preventive strategies for CINP are largely insufficient, as they fail to address the underlying peripheral nerve damage, highlighting an urgent need for the development of new drugs. This study aimed to investigate the dual-function effects on normal cell protection and tumor suppression of BMX-001, a redox-active manganese metalloporphyrin that has demonstrated antioxidant and anti-inflammatory properties, which offers potential in protecting central nervous system tissues and treating CINP. Methods: This study assessed BMX-001's different roles in protecting normal cells while acting as a pro-oxidant and pro-inflammatory molecule in cancer cells in vitro. We also evaluated its neuroprotective effect in preclinical PTX-induced CINP models in vivo. Results: Our results showed significant reductions in mechanical and cold allodynia, decreased pro-inflammatory cytokine levels, and restored antioxidant capacity in peripheral nerves and dorsal root ganglia (DRGs) following BMX-001 treatment. Conclusions: Overall, our study highlights the therapeutic potential of BMX-001 to mitigate CINP and enhance anticancer efficiency. Its dual-selective mechanism supports the future clinical investigation of BMX-001 as a novel adjunct to chemotherapeutic regimens.

Keywords: BMX-001; neuropathy; paclitaxel; reactive oxygen species; satellite glial cells.

Figure 1

Schematic of the in vitro and in vivo experimental designs. (A) For in vitro experiments, SGCs and MDA-MB-231 cells were seeded in 96-well plates and cultured overnight in DMEM with 10% FBS and 1% P/S. The cells were treated with PTX and BMX-001 for 24 h and collected for the following CCK-8 test, H2DCFDA ROS staining, qPCR, and antioxidant enzyme activity assays. (B) For the in vivo experiment, female C57BL/6 mice were randomly assigned to one of 4 groups in vivo: Sham, PTX, BMX-001, or PTX + BMX-001. Intraperitoneal injections of 8 mg/kg PTX per dose or vehicle solution (ethanol, Cremophor EL, and saline) were given on Days 1, 3, 5, and 7. Subcutaneous injections of 0.5 mg/kg per dose of BMX-001 or PBS were given on Days 1, 3, 5, and 7 and twice a week before the end point at 21 days. Behavioral testing of mice was evaluated using a von Frey filament assay for mechanical allodynia, an acetone drop test for cold allodynia, and a hot plate test for thermal hyperalgesia on the timepoints indicated.

Figure 2

BMX-001 reduced the total ROS elevated by PTX in SGCs but increased ROS in MDA-MB-231 cells in vitro. (A,B) SGCs were cultured with PTX or BMX in various titrations for 24 h before evaluation of the cell viability by a CCK-8 test (n = 4–7). (C,D) Total ROS levels in SGCs and MDA-MB-231 cells in the Control group, PTX group, PTX with 0.25 μM BMX-001 group, or PTX with 0.5 μM BMX-001 group for 24 h (n = 6). (E) H2DCFDA fluorescence staining in SGCs after being treated with medium, 0.5 µM BMX-001, 1 µM PTX, or 1 µM PTX + 0.5 µM BMX-001 for 24 h (Scale bar = 100 μm, all figures share same scale bar). (F) H2DCFDA fluorescence staining in MDA-MB-231 after being treated with medium, 0.25 µM BMX-001, 0.5 µM PTX, or 0.5 µM PTX + 0.25 µM BMX-001 for 24 h (Scale bar = 200 μm, all panels share same scale bar). * p < 0.05, ** p < 0.01, *** p < 0.001 compared to 0 µM PTX or 0 µM BMX-001.

Figure 3

BMX-001 regulated inflammation and antioxidants differently in SGCs and MDA-MB-231. (A) Gene expressions of TNF-alpha and Nrf2 in SGCs recorded by qPCR (n = 4). (B) Gene expressions of TNF-alpha and NF-kB in MDA-MB-231 recorded by qPCR (n = 4). * p < 0.05, ** p < 0.01, *** p < 0.001, ns: no significant difference.

Figure 4

BMX-001 regulated antioxidant enzyme activity differently in SGCs and MDA-MB-231. SOD (A), catalase (B), and GPx (C) enzyme activity in SGCs and MDA-MB-231 cells after the PTX and BMX-001 treatments (SGCs treatments: 1 μM PTX, 0.5 μM BMX-001; MDA-MB-231 treatments: 0.5 μM PTX, 0.25 μM BMX-001) (n = 6). * p < 0.05, ** p < 0.01, *** p < 0.001 compared with the Control group, ns: no significant difference.

Figure 5

BMX-001 alleviated mechanical and thermal allodynia in a mouse model of CINP. (A–C) Behavioral test results of the in vivo CINP model mice described in Figure 1B measured by a von Frey test, acetone drop test, and hot plate test (n = 7). PTX: 8 mg/kg per dose (32 mg/kg for accumulated four doses in one week); BMX-001: 0.5 mg/kg per dose (4 mg/kg for accumulated eight doses in three weeks); PTX + BMX: PTX and BMX treatments combined. Statistical significance for Control vs. PTX Control vs. BMX-001, and Control vs. PTX + BMX-001: * p < 0.05, *** p <0.001, ns: no significant difference; PTX vs. PTX + BMX-001: & p < 0.05, && p < 0.01, &&& p < 0.001.

Figure 6

BMX-001 ameliorated inflammation, ROS, and hyposensitivity in peripheral nerves of mice with CINP. (A–C) Immunostaining results of TRPV1, IBA-1, and TNF-alpha in the isolated mouse DRGs from the in vivo study mice (Scale bar = 100 μm, all panels share the same scale bar). (D) Quantification of the fluorescent signal intensity of the TRPV1 in (A), positive area of IBA-1 in (B), and fluorescent signal intensity of TNF-alpha in (C) (n = 6). (E) Gene expressions of TNF-alpha, IL-6, Nrf2, and TRPV1 in the isolated mouse DRGs from the in vivo study mice recorded by qPCR (n = 4). * p < 0.05, ** p < 0.01, *** p < 0.001, ns: no significant difference compared with Sham group.

Figure 7

BMX-001’s potential roles in PTX-induced CINP and its differential effects on normal cells versus MDA-MB-231 cancer cells. In CINP, PTX induces the expression of pro-inflammatory cytokines, like IL-6 and TNF-α, in SGCs and TRPV1 sensitization in DRG through ROS accumulation, leading to glial activation, recruitment of immune cells, neuronal damage, and thus hypersensitization. In normal cells, like SGCs and neuronal cells, BMX-001 reduces the total ROS level and TNF-α expression through quick scavenging superoxide, upregulation of Nrf2, and enhanced activity of catalase, which protect the DRG neurons from PTX-induced CINP. Meanwhile, in cancer cells like MDA-MB-231, BMX-001 enhances excess oxidative stress by promoting H₂O₂ accumulation, which leads to inefficient ROS and H₂O₂ clearance because of the exhausted antioxidant enzymes, like MnSOD, catalase, and GPx, and thus the enhanced cell death and stimulated immune cell recruitment.