Bortezomib-induced Neuropathic Pain Research Articles

Targeting metabolic pathways alleviates bortezomib-induced neuropathic pain without compromising anticancer efficacy in a sex-specific manner.

Chemotherapy-induced peripheral neuropathy (CIPN) is a debilitating side effect of cancer treatment that significantly impacts patients' quality of life. This study investigated the effects of targeting metabolic pathways on bortezomib-induced neuropathic pain and tumor growth using a Lewis lung carcinoma (LLC) mouse model, while exploring potential sex differences. Male and female C57BL/6J mice were implanted with LLC cells and treated with bortezomib alone or in combination with metformin, dichloroacetate (DCA), or oxamate. Tactile allodynia was assessed using von Frey filaments. Tumor volume and weight were measured to evaluate tumor growth. Metformin, DCA, and oxamate effectively attenuated bortezomib-induced neuropathic pain without compromising the anticancer efficacy of bortezomib in both male and female mice. The LLC model exhibited a paraneoplastic neuropathy-like phenotype. Significant sex differences were observed, with male mice exhibiting larger tumors compared to females. Oxamate was more effective in alleviating allodynia in males, while metformin and DCA showed greater efficacy in reducing tumor growth in females. Targeting metabolic pathways can alleviate CIPN without interfering with bortezomib's anticancer effects. The LLC model may serve as a tool for studying paraneoplastic neuropathy. Sex differences in tumor growth and response to metabolic interventions highlight the importance of considering sex as a biological variable in preclinical and clinical studies investigating cancer biology, CIPN, and potential therapeutic interventions.

Genetic Risk Factors for Bortezomib-induced Neuropathic Pain in an Asian Population: A Genome-wide Association Study in South Korea

Bortezomib-induced neuropathic pain (BINP) poses a challenge in multiple myeloma (MM) treatment. Genetic factors play a key role in BINP susceptibility, but research has predominantly focused on Caucasian populations. This research explored novel genetic risk loci and pathways associated with BINP development in Korean MM patients while evaluating the reproducibility of variants from Caucasians. Clinical data and buffy coat samples from 185 MM patients on bortezomib were collected. The cohort was split into discovery and validation cohorts through random stratification of clinical risk factors for BINP. Genome-wide association study was performed on the discovery cohort (n = 74) with Infinium Global Screening Array-24 v3.0 BeadChip (654,027 single nucleotide polymorphism [SNPs]). Relevant biological pathways were identified using the pathway scoring algorithm. The top 20 SNPs were validated in the validation cohort (n = 111). Previously reported SNPs were validated in the entire cohort (n = 185). Pathway analysis of the genome-wide association study results identified 31 relevant pathways, including immune systems and endosomal vacuolar pathways. Among the top 20 SNPs from the discovery cohort, 16 were replicated, which included intronic variants in ASIC2 and SMOC2, recently implicated in nociception, as well as intergenic variants or long noncoding RNAs. None of the 17 previously reported SNPs remained significant in our cohort (rs2274578, P = .085). This study represents the first investigation of novel genetic loci and biological pathways associated with BINP occurrence. Our findings, in conjunction with existing Caucasian studies, expand the understanding of personalized risk prediction and disease mechanisms. PerspectiveThis article is the first to explore novel genetic loci and pathways linked to BINP in Korean MM patients, offering novel insights beyond the existing research focused on Caucasian populations into personalized risk assessment and therapeutic strategies of BINP.

MiR-672-5p-Mediated Upregulation of REEP6 in Spinal Dorsal Horn Participates in Bortezomib-Induced Neuropathic Pain in Rats.

Evidence shows that miRNAs are deeply involved in nervous system diseases, but whether miRNAs contribute to the bortezomib (BTZ)-induced neuropathic pain remains unclear. We aimed to investigate whether miRNAs contribute to bortezomib (BTZ)-induced neuropathic pain and explore the related downstream cascades. The level of miRNAs in the spinal dorsal horn was explored using miRNA microarray and PCR. MiR-672-5p was significantly downregulated in dorsal horn neurons in the rats with BTZ treatment. Intrathecal injection of miR-672-5p agomir blunted the increase of the amplitude and frequency of sEPSCs in dorsal horn neurons and mechanical allodynia induced by BTZ. In addition, the knockdown of miR-672-5p by intrathecal injection of antagomir increased the amplitude and frequency of sEPSCs in dorsal horn neurons and decreased the mechanical withdrawal threshold in naïve rats. Furthermore, silico analysis and the data from subsequent assays indicated that REEP6, a potential miR-672-5p-regulating molecule, was increased in the spinal dorsal horn of rats with BTZ-induced neuropathic pain. Blocking REEP6 alleviated the mechanical pain behavior induced by BTZ, whereas overexpressing REEP6 induced pain hypersensitivity in naïve rats. Importantly, we further found that miR-672-5p was expressed in the REEP6-positive cells, and overexpression or knockdown of miR-672-5p reversely regulated the REEP6 expression. Bioinformatics analysis and double-luciferase reporter assay showed the existence of interaction sites between REEP6 mRNA and miR-672-5p. Overall, our study demonstrated that miR-672-5p directly regulated the expression of REEP6, which participated in the neuronal hyperexcitability in the spinal dorsal horn and neuropathic pain following BTZ treatment. This signaling pathway may potentially serve as a novel therapeutic avenue for chemotherapeutic-induced mechanical hypersensitivity.

Metformin Relieves Bortezomib-Induced Neuropathic Pain by Regulating AMPKa2-Mediated Autophagy in the Spinal Dorsal Horn.

Chemotherapy-induced neuropathic pain is a major clinical problem with limited treatment options. Here, we show that metformin relieves bortezomib (BTZ)-evoked induction and maintenance of neuropathic pain by preventing the reduction in the expression of Beclin-1, an autophagy marker, in the spinal dorsal horn. Application of rapamycin or 3-methyladenine, autophagy inducer and inhibitor, respectively, affected the mechanical allodynia differently. Co-application of 3-methyladenine and metformin partially inhibited the effect of metformin in recovering Beclin-1 expression and in reducing the pain behavior in rats subjected to BTZ treatment. BTZ treatment also reduced the expression of AMPKa2 in the dorsal horn, which was recovered by metformin treatment. Overexpression of AMPKa2 attenuated the BTZ-evoked reduction in Beclin-1 expression and mechanical allodynia, whereas intrathecal injection of AMPKa2 siRNA decreased the Beclin-1 expression and induced mechanical allodynia in naive rats. Moreover, BTZ treatment increased the GATA3 expression in the dorsal horn, and GATA3 siRNA attenuated the AMPKa2 downregulation and mechanical allodynia induced by BTZ. Chromatin immunoprecipitation further showed that BTZ induced an increased recruitment of GATA3 to multiple sites in the AMPKa2 promoter region. Furthermore, decreased acetylation and increased methylation of histone H3 in the AMPKa2 promoter in the spinal dorsal horn was detected after BTZ treatment. Our findings suggest that metformin may regulate AMPKa2-mediated autophagy in the dorsal horn and alleviate the behavioral hypersensitivity induced by BTZ.

The Actions and Mechanisms of P2X7R and p38 MAPK Activation in Mediating Bortezomib-Induced Neuropathic Pain.

The proteasome inhibitor bortezomib (BTZ) is a potent first-line anticancer drug for multiple myeloma; nonetheless, it induced peripheral neuropathy. It has been suggested that many cytokines may play a role in mediating neuropathic pain, but the underlying molecular mechanism is not fully understood. Recent studies have shown that neuropathic pain is closely related to the purinergic ligand-gated ion channel 7 receptor (P2X7R), one of the P2X receptors, which is richly expressed in glial cells. P2X7-p38 pathway is correlated with microglia- and satellite glial cell- (SGC-) mediated neuropathic pain. However, the association of P2X7R and p38MAPK in mediating BTZ-induced neuropathic pain remains unclear. In this study, the relationship between P2X7R activation and p38 phosphorylation in the dorsal root ganglion (DRG) and spinal dorsal horn (SDH) in the development and maintenance of BTZ-induced neuropathic pain was elucidated. The results showed that BTZ increased mechanical thresholds in rats, accompanied with upregulation of P2X7R expression and p38MAPK phosphorylation, indicating that P2X7R and p38MAPK are key molecules in the development and maintenance of BTZ-induced neuropathic pain. Inhibiting p38MAPK phosphorylation with SB203580 resulted in downregulation of P2X7R expression levels. Inhibition of P2X7R with Brilliant Blue G (BBG) reversed neuropathic pain might decrease through the expression of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and IL-6 via inhibiting p38MAPK phosphorylation. The P2X7R/p38MAPK signaling pathway in SGCs of DRG and microglia of SDH might be a potential pharmacological target behind this mechanism as an opportunity to relieve BTZ-induced neuropathic pain.

Sexually dimorphic therapeutic response in bortezomib-induced neuropathic pain reveals altered pain physiology in female rodents.

Chemotherapy-induced neuropathic pain (CINP) in both sexes compromises many current chemotherapeutics and lacks an FDA-approved therapy. We recently identified the sphingosine-1-phosphate receptor subtype 1 (S1PR1) and A3 adenosine receptor subtype (A3AR) as novel targets for therapeutic intervention. Our work in male rodents using paclitaxel, oxaliplatin, and bortezomib showed robust inhibition of CINP with either S1PR1 antagonists or A3AR agonists. The S1PR1 functional antagonist FTY720 (Gilenya) is FDA-approved for treating multiple sclerosis, and selective A3AR agonists are in advanced clinical trials for cancer and inflammatory disorders, underscoring the need for their expedited trials in patients with CINP as chemotherapy adjuncts. Our findings reveal that S1PR1 antagonists and A3AR agonists mitigate paclitaxel and oxaliplatin CINP in female and male rodents, but failed to block or reverse bortezomib-induced neuropathic pain (BINP) in females. Although numerous mechanisms likely underlie these differences, we focused on receptor levels. We found that BINP in male rats, but not in female rats, was associated with increased expression of A3AR in the spinal cord dorsal horn, whereas S1PR1 levels were similar in both sexes. Thus, alternative mechanisms beyond receptor expression may account for sex differences in response to S1PR1 antagonists. Morphine and duloxetine, both clinical analgesics, reversed BINP in female mice, demonstrating that the lack of response is specific to S1PR1 and A3AR agents. Our findings suggest that A3AR- and S1PR1-based therapies are not viable approaches in preventing and treating BINP in females and should inform future clinical trials of these drugs as adjuncts to chemotherapy.

Bortezomib and metformin opposingly regulate the expression of hypoxia-inducible factor alpha and the consequent development of chemotherapy-induced painful peripheral neuropathy.

Chemotherapy-induced painful peripheral neuropathy is a significant clinical problem that is associated with widely used chemotherapeutics. Unfortunately, the molecular mechanisms by which chemotherapy-induced painful peripheral neuropathy develops have remained elusive. The proteasome inhibitor, bortezomib, has been shown to induce aerobic glycolysis in sensory neurons. This altered metabolic phenotype leads to the extrusion of metabolites which sensitize primary afferents and cause pain. Hypoxia-inducible factor alpha is a transcription factor that is known to reprogram cellular metabolism. Furthermore, hypoxia-inducible factor 1 alpha protein is constantly synthesized and undergoes proteasomal degradation in normal conditions. However, metabolic stress or hypoxia stabilizes the expression of hypoxia-inducible factor 1 alpha leading to the transcription of genes that reprogram cellular metabolism. This study demonstrates that treatment of mice with bortezomib stabilizes the expression of hypoxia-inducible factor 1 alpha. Moreover, knockdown of hypoxia-inducible factor 1 alpha, inhibition of hypoxia-inducible factor 1 alpha binding to its response element, or limiting its translation by using metformin prevent the development of bortezomib-induced neuropathic pain. Strikingly, the blockade of hypoxia-inducible factor 1 alpha expression does not attenuate mechanical allodynia in mice with existing bortezomib-induced neuropathic pain. These results establish the stabilization of hypoxia-inducible factor 1 alpha expression as the molecular mechanism by which bortezomib initiates chemotherapy-induced painful peripheral neuropathy. Crucially, these findings reveal that the initiation and maintenance of bortezomib-induced neuropathic pain are regulated by distinct mechanisms.

GATA3-dependent epigenetic upregulation of CCL21 is involved in the development of neuropathic pain induced by bortezomib.

The incidence of bortezomib-induced neuropathic pain hampers the progress of therapy for neoplasia and also negatively affects the quality of life of patients. However, the molecular mechanism underlying bortezomib-induced neuropathic pain remains unknown. In this study, we found that the application of bortezomib significantly increased the expression of GATA-binding protein 3 (GATA3) in the spinal dorsal horn, and intrathecal administration of GATA3 siRNA attenuated mechanical allodynia. Furthermore, chromatin immunoprecipitation sequencing showed that bortezomib treatment induced the redistribution of GATA3 to transcriptional relevant regions. Notably, combined with the results of mRNA microarray, we found that C–C motif chemokine ligand 21 (CCL21) had an increased GATA3 binding and upregulated mRNA expression in the dorsal horn after bortezomib treatment. Next, we found that bortezomib treatment induced CCL21 upregulation in the spinal neurons, which was significantly reduced upon GATA3 silencing. Blockade of CCL21 using the neutralizing antibody or special siRNA ameliorated mechanical allodynia induced by bortezomib. In addition, bortezomib treatment increased the acetylation of histone H3 and the interaction between GATA3 and CREB-binding protein. GATA3 siRNA suppressed the CCL21 upregulation by decreasing the acetylation of histone H3. Together, these results suggested that activation of GATA3 mediated the epigenetic upregulation of CCL21 in dorsal horn neurons, which contributed to the bortezomib-induced neuropathic pain.

Dysregulation of sphingolipid metabolism contributes to bortezomib-induced neuropathic pain.

The development of chemotherapy-induced painful peripheral neuropathy is a major dose-limiting side effect of many chemotherapeutics, including bortezomib, but the mechanisms remain poorly understood. We now report that bortezomib causes the dysregulation of de novo sphingolipid metabolism in the spinal cord dorsal horn to increase the levels of sphingosine-1-phosphate (S1P) receptor 1 (S1PR1) ligands, S1P and dihydro-S1P. Accordingly, genetic and pharmacological disruption of S1PR1 with multiple S1PR1 antagonists, including FTY720, blocked and reversed neuropathic pain. Mice with astrocyte-specific alterations of S1pr1 did not develop neuropathic pain and lost their ability to respond to S1PR1 inhibition, strongly implicating astrocytes as a primary cellular substrate for S1PR1 activity. At the molecular level, S1PR1 engaged astrocyte-driven neuroinflammation and altered glutamatergic homeostasis, processes blocked by S1PR1 antagonism. Our findings establish S1PR1 as a target for therapeutic intervention and provide insight into cellular and molecular pathways. As FTY720 also shows promising anticancer potential and is FDA approved, rapid clinical translation of our findings is anticipated.

Clinical, electrophysiological, and cutaneous innervation changes in patients with bortezomib-induced peripheral neuropathy reveal insight into mechanisms of neuropathic pain.

Bortezomib is a mainstay of therapy for multiple myeloma, frequently complicated by painful neuropathy. The objective of this study was to describe clinical, electrophysiological, and pathological changes of bortezomib-induced peripheral neuropathy (BiPN) in detail and to correlate pathological changes with pain descriptors. Clinical data, nerve conduction studies, and lower leg skin biopsies were collected from 22 BiPN patients. Skin sections were immunostained using anti-protein gene product 9.5 (PGP9.5) and calcitonin gene-related peptide (CGRP) antibodies. Cumulative bortezomib dose and clinical assessment scales indicated light-moderate sensory neuropathy. Pain intensity >4 (numerical rating scale) was present in 77% of the patients. Median pain intensity and overall McGill Pain Questionnaire (MPQ) sum scores indicated moderate to severe neuropathic pain. Sural nerve sensory nerve action potentials were abnormal in 86%, while intraepidermal nerve fiber densities of PGP9.5 and CGRP were not significantly different from healthy controls. However, subepidermal nerve fiber density (SENFD) of PGP9.5 was significantly decreased and the axonal swelling ratio, a predictor of neuropathy, and upper dermis nerve fiber density (UDNFD) of PGP9.5, presumably representing sprouting of parasympathetic fibers, were significantly increased in BiPN patients. Finally, significant correlations between UDNFD of PGP9.5 versus the evaluative Pain Rating Index (PRI) and number of words count (NWC) of the MPQ, and significant inverse correlations between SENFD/UDNFD of CGRP versus the sensory-discriminative MPQ PRI/NWC were found. BiPN is a sensory neuropathy, in which neuropathic pain is the most striking clinical finding. Bortezomib-induced neuropathic pain may be driven by sprouting of parasympathetic fibers in the upper dermis and impaired regeneration of CGRP fibers in the subepidermal layer.

Blocking TRPA1 and TNF-α Signal Improves Bortezomib-Induced Neuropathic Pain

Background/Aims: Bortezomib (BTZ) is largely used as a chemotherapeutic agent for the treatment of multiple myeloma. However, one of the significant limiting complications of BTZ is painful peripheral neuropathy during BTZ therapy. The purpose of this study was to examine the underlying mechanisms leading to neuropathic pain induced by BTZ. Methods: ELISA and western blot analysis were used to examine the levels of tumor necrosis factor alpha (TNF-α) and its receptor, transient receptor potential ankyrin 1 (TRPA1) and intracellular p38-MAPK and JNK signal in the lumbar dorsal root ganglion. Behavioral test was performed to determine mechanical pain and cold sensitivity in a rat model. Results: Systemic injection of BTZ significantly increased mechanical pain and cold sensitivity as compared with control animals (P< 0.05 vs. control rats). Our data also showed that protein expression of TRPA1 was upregulated in the dorsal root ganglion of BTZ rats and blocking TRPA1 attenuated mechanical pain and cold sensitivity in control rats and BTZ rats (P< 0.05 vs. vehicle control). Notably, the inhibitory effect of blocking TRPA1 on mechanical pain and cold sensitivity was smaller in BTZ rats than that in control rats. In addition, a blockade of TNF-α attenuated intracellular p38-MAPK and JNK signal in the dorsal root ganglion. This also decreased TRPA1 expression and alleviated mechanical hyperalgesia and cold hypersensitivity in BTZ rats. Conclusion: We revealed specific signaling pathways leading to neuropathic pain induced by chemotherapeutic BTZ. The data also suggest that blocking TRPA1 and tumor necrosis factor alpha is beneficial to alleviate neuropathic pain during BTZ intervention.

(337) Bortezomib-induced neuropathic pain is blocked and reversed by blocking the S1P/S1PR1 axis

Bortezomib-induced peripheral neuropathy (BIPN) is a major dose-limiting factor for bortezomib, which is used to treat multiple myeloma. BIPN, often accompanied by chronic neuropathic pain, can last for months to years after treatment cessation, decreasing the patient’s quality of life; there are currently no effective treatments. Our lab has recently shown that the spingosine-1-phosphate (S1P) to S1PR1 pathway is important in the initiation and maintenance of BIPN, through peripheral and central mechanisms.

Inhibition of chemotherapy‐induced neuropathic pain with S1P receptor modulators

Chemotherapy‐induced peripheral neuropathy (CIPN), accompanied by chronic neuropathic pain, is the major dose‐limiting toxicity of numerous antitumor agents. We now show that paclitaxel‐induced neuropathic pain is associated with increased sphingosine 1‐phosphate (S1P) formation in spinal cord acting through S1P1 receptor‐mediated NF‐κB and MAPKs activation and proinflammatory cytokine release. Inhibition of spinal cord S1P‐to‐S1PR1 signaling with the S1PR1 antagonist, W146, or FTY720, a FDA‐approved functional S1PR1 antagonist for treating multiple sclerosis, attenuated neuroinflammation and neuropathic pain. The effects of FTY720 occurred at non‐immunosuppressive doses without interfering with antitumor actions and extend to oxaliplatin and bortezomib‐induced neuropathic pain. Our findings identify the key role of the S1P‐to‐ S1PR1 pathway in CIPN and provide a first mechanistic insight into the S1P‐mediated biochemical pathways; establishing a pharmacological basis for S1PR modulators as chemotherapeutic adjuncts to block CIPN. Supported by Saint Louis University President Research Funds, Saint Louis University Cancer Center, Lymphoma and Leukemia Society Translational Research Grant.

Review Bortezomib-induced painful neuropathy in patients with multiple myeloma

Neurotoxicity towards the peripheral nervous system which appears clinically in the form of painful neuropathy is an essential dose-limiting factor during the treatment of multiple myeloma. In this review article different forms of this painful neuropathy are presented together with currently available diagnostic tools which are usually applied to confirm the diagnosis. Also, the most often used neurological scales estimating neurological deficit are presented. Special attention is paid to the management of the reversibility of bortezomib-induced neuropathic pain.

Controlled-release oxycodone for the treatment of bortezomib-induced neuropathic pain in patients with multiple myeloma

Bortezomib, a proteasome inhibitor drug very effective against multiple myeloma, may induce the so-called bortezomib-induced peripheral neuropathy (BIPN), hardly manageable with common analgesic drugs. This study assessed the effectiveness of controlled-release (CR) oral oxycodone in controlling pain and its interference on daily functions of patients with hematologic malignancies affected by BIPN. Forty-six patients (median age, 62 years) affected by myeloma and lymphoma, complaining of BIPN-related pain of moderate-to-severe intensity and unresponsive to previous analgesic treatments, were treated with CR oxycodone. The intensity of continuous and brief pain (BP) along with interference of pain with the common daily dimensions of feeling and function were evaluated by using an 11-point numerical rating scale (NRS); a global patient evaluation of efficacy was also performed. The daily average dose of CR oxycodone administered was 28.46 mg (range, 20-80 mg). The pain intensity decreased from a mean NRS value of 7.6 at baseline to 1.3 on day 14. The frequency of BP was reduced from 61 to 47% of patients and its intensity from 7.4 to 3.1 NRS score. A similar trend to decreasing values was observed for all the daily life functions. Slight- or mild-intensity side effects were observed in 23 patients (51%). At the end of the study, 75% of patients found the treatment effective or very effective. CR oxycodone for relief of BIPN-related pain was effective and well tolerated. The pain control significantly improved also the quality of the daily life functions, which are usually compromised in these suffering patients.

Abstract 3725: Bortezomib-induced neuropathic pain: Evaluation of anti nociceptive effect of a new analgesic compound

Abstract Bortezomib (Btz) is a highly effective and widely used antineoplastic drug for the treatment of many tumors, primarily multiple myeloma. Despite its effectiveness, the use of this proteasome inhibitor is limited by its toxicity. Among Btz side effects, peripheral neurotoxicity is a major and clinically relevant problem. In fact, since the earliest Phase I and Phase II studies, sensory peripheral neuropathy emerged as a dose-limiting side effect. Moreover, a significant proportion of Btz-treated patients developed severe neuropathic pain. The treatment of Btz-induced neuropathic pain is extremely difficult with the currently available drugs and still remains a major challenge for oncologists and neurologists. Aim of this study was to demonstrate if the new analgesic compound CR4056 could reverse the neuropathic pain induced by a chronic treatment with Btz in the rat. The anti-nociceptive and dose-dependent effect of CR4056 was assessed in a well-established experimental rat model in which Btz was administered to Wistar rats (0.20 mg/kg three times/week for 8 weeks) followed by treatment with CR4056 (6, 20 or 60 mg/kg daily p.o.) or buprenorphine administered 28,8 µg/kg/day p.o. for 2 weeks. Body weight change, hematological and histopathological parameters, nerve conduction velocity (NCV) and sensory behavioral tests were evaluated during the experiment. No remarkable effect of Btz administration or of any dose of CR4056 was observed in the hematological parameters and blood chemistry. After 8 weeks of treatment, Btz induced a severe reduction in NCV; this impairment was not reversed by CR4056 or by buprenorphine. The behavioral assessment showed a significant mechanical allodynia in rats treated with Btz for 8 weeks (delta vs. controls −6 g). Buprenorphine significantly reduced Btz-induced allodynia during the fist day by about 63%. However, this effect was lost during the following days of treatment (i.e 20% reduction on the 3rd day). The mid and high dose of CR4056 (20 and 60 mg/kg) showed a significant (i.e &amp;gt; 80 %) reduction of allodynia till the 3rd day of administration, afterwards a slight reduction in efficacy was recorded. On the contrary, the oral daily administration of 6 mg/kg CR4056 persistently counteracted Btz-induced allodynia, showing an even complete reversion after 2 weeks of treatment. The present study gives evidence for a relevant and persistent anti-allodynic effect of CR4056, suggesting a role for CR4056 in the management of neuropathic pain in patients treated with Btz. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3725.

Bortezomib-induced painful neuropathy in rats: A behavioral, neurophysiological and pathological study in rats

Bortezomib is a proteasome inhibitor showing strong antitumor activity against many tumors, primarily multiple myeloma. Bortezomib-induced neuropathic pain is the main side effect and the dose-limiting factor of the drug in clinical practice. In order to obtain a pre-clinical model to reproduce the characteristic pain symptoms in bortezomib-treated patients, we developed an animal model of bortezomib-induced nociceptive sensory neuropathy. In this study, bortezomib (0.15 or 0.20 mg/kg) was administered to Wistar rats three times/week for 8 weeks, followed by a 4 week follow-up period. At the end of the treatment period a significant decrease in weight gain was observed in the treated groups vs. controls, and hematological and histopathological parameters were evaluated. After the treatment period, both doses of bortezomib induced a severe reduction in nerve conduction velocity and demonstrated a dose-cumulative effect of the drug. The sensory behavioral assessment showed the onset of mechanical allodynia, while no effect on thermal perception was observed. Sciatic nerves and dorsal root ganglia (DRG) were collected at the end of the 8-week treatment and at the end of the follow-up period. The pathological examination revealed a dose-dependent axonopathy of the unmyelinated fibers in nerves of treated animals. No pathological alteration in most of DRG satellite cells and neurons was observed. Therefore, this animal model may be useful for studying the neurotoxicity and pain onset mechanisms related to bortezomib treatment.

From Bench to Bedside: A Case of Rapid Reversal of Bortezomib-Induced Neuropathic Pain by the TRPM8 Activator, Menthol

From Bench to Bedside: A Case of Rapid Reversal of Bortezomib-Induced Neuropathic Pain by the TRPM8 Activator, Menthol

Quantitative Sensory Findings in Patients With Bortezomib-Induced Pain

Bortezomib (PS-341) is a newly developed proteosome inhibitor that shows extremely promising antineoplastic effects against a variety of neoplasias. Neuropathic pain is emerging as a major complication of bortezomib. Although clinical reports have appeared in the literature describing the general symptoms of bortezomib chemoneuropathy, specific quantitative sensory data that detail the sensory deficits that might yield insight to the primary afferent dysfunction contributing to this pain is lacking. In this report, it is shown that patients with bortezomib-induced neuropathic pain have significantly elevated touch detection threshold and slotted peg board time, impaired sharpness detection, and elevated thresholds for the detection of skin warming and heat pain. Patients also had increased reports of cold pain. These data indicate that bortezomib-induced neuropathy is associated with deficits in Abeta, Adelta, and C caliber primary afferent fibers. This work demonstrates that pain induced by the chemotherapy drug bortezomib is accompanied by dysfunction in all fiber types in sensory nerves. Impaired Abeta and C sensory function also extends into areas of skin that are not perceived as affected by pain.