Background & Aims
Cancer ranks as the second leading global cause of death1. Breast cancer sees over 2.3 million new cases annually1,2. Advances in oncological therapies result in prolonged survival, yet many breast cancer survivors contend with sequelae, predominantly pain1. Pain adversely impacts the patient’s quality of life and may prompt premature treatment cessation1. Aromatase inhibitors (AI) are most used for hormone receptor-positive breast cancer2, 3. Anastrozole, the predominant used AI (64%), induces musculoskeletal pain in 30–60% of users. In some cases, patients exhibit diffuse (22%), mixed (11%), or neuropathic (9%) pain4,5. Mechanisms involved in AI-induced painful symptoms are not fully understood. Because the TRPV4 is a non-selective cationic channel activated by hypo-osmolarity, mechanical stimulus, and innocuous warm temperatures (27–35 °C) and is involved in pathological pain6,7 we investigated the role of TRPV4 in anastrozole-induced musculoskeletal pain in mice.
Methods
Anastrozole (0.2 mg/kg) or vehicle was administered orally (p.o.) in male C57BL/6 mice. Mechanical allodynia (von Frey test) and muscle strength (Grip test) were evaluated before (baseline) and at 2 h after its administration (time 0, baseline 2). The TRPV4 antagonist (HC067047; 10 mg/kg, intraperitoneal, i.p.) was administered 2 h after anastrozole. The von Frey and grip test were evaluated 0.5 h up to 3 h after treatments. Sub-nociceptive doses of TRPV4 agonists [4?-PDD (3 nmol/paw) or hypotonic solution (20 µL/paw)] were injected by intraplantar (i.pl.; 20 µL/paw) route in previously anastrozole-treated mice. Von Frey and grip test were evaluated from 0.5 to 5 h after injections. Other animal groups received HC067047 2 h after anastrozole, and after 0.25 h, the same animals were treated with sub-nociceptive doses of their agonists, 4?-PDD or hypotonic solution by i.pl. route. After 1 h of agonist injections, the von Frey and grip test were performed.
Results
Mice treated with anastrozole developed mechanical allodynia and loss of muscle strength. The TRPV4 antagonist HC067047 reduced the anastrozole-induced mechanical allodynia and muscle strength loss from 0.5 to 2 h after its administration. The intraplantar (i.pl.) injection of TRPV4 agonists, hypotonic solution or 4?-PDD enhanced the mechanical allodynia (from 0.5 to 2 h) and muscle strength loss (from 0.5 to 3 h) in anastrozole-treated mice. HC067047 administered 0.25 h before the 4?-PDD reduced the mechanical allodynia (from 0.5 h to 1 h) and muscle strength loss (from 0.5 h up to 3 h) of anastrozole-treated mice. HC067047 administered 0.25 h before the hypotonic solution, reduced the mechanical allodynia and muscle strength loss in animals treated with anastrozole at 1 hour after agonist administration.
Conclusions
AIs are the main endocrine treatment for postmenopausal women diagnosed with hormone receptor-positive breast cancer. However, they cause musculoskeletal pain, leading to non-adherence or discontinuation of therapy2,3,4. Efforts have been made to understand the mechanisms involved in painful symptoms related to AI use to manage them better. In this study, the intraplantar injection of TRPV4 agonists, 4?-PDD or hypotonic solution, enhanced the mechanical allodynia and loss of muscle strength caused by anastrozole in mice. The pre-treatment with TRPV4 antagonist HC067047 attenuated the mechanical allodynia and muscle strength loss induced by TRPV4 agonists in previously anastrozole-treated mice. We used TRPV4 antagonists and agonists to show that mice’s anastrozole-induced musculoskeletal pain is TRPV4 channel-dependent. Thus, the TRPV4 channels act as sensors of extracellular and intracellular changes6,7, making them potential therapeutic targets for treating pathological pain.
References
1. Sung H, Ferlay J, Siegel RL et al (2021) Global Cancer Statistics 2020: GLOBOCAN estimates of incidence and Mortality Worldwide for 36 cancers in 185 countries. CA Cancer J Clin 71:209–249. https://doi.org/10.3322/caac.21660
2. Waks AG, Winer EP (2019) Breast Cancer Treatment. JAMA 321:288. https://doi.org/10.1001/jama.2018.19323
3. Tenti S, Correale P, Cheleschi S et al (2020) Aromatase Inhibitors Induced Musculoskeletal Disorders: current knowledge on clinical and molecular aspects. Int J Mol
4. Laroche F, Coste J, Medkour T et al (2014) Classification of and risk factors for Estrogen Deprivation Pain Syndromes related to aromatase inhibitor treatments in women with breast Cancer: a prospective Multicenter Cohort Study. J Pain 15:293–303. https://doi.org/10.1016/j.jpain.2013.11.004
5. Crew KD, Greenlee H, Capodice J et al (2007) Prevalence of joint symptoms in Postmenopausal Women taking aromatase inhibitors for early-stage breast Cancer. J Clin Oncol 25:3877–3883.https://doi.org/10.1200/JCO.2007.10.7573
6. Kumar H, Lee SH, Kim KT et al (2018) TRPV4: a Sensor for Homeostasis and pathological events in the CNS. Mol Neurobiol 55:8695–8708. https://doi.org/10.1007/s12035-018-0998-8
7. Grace MS, Bonvini SJ, Belvisi MG, McIntyre P (2017) Modulation of the TRPV4 ion channel as a therapeutic target for disease. Pharmacol Ther 177:9–22. https://doi.org/10.1016/j.pharmthera.2017.02.019
Presenting Author
João Pedro de Vargas Lopes
Poster Authors
João Pedro de Vargas Lopes
Federal University of Santa Maria
Lead Author
Maria Fialho
Federal University of Santa Maria, Santa Maria, RS, Brazil
Lead Author
Evelyne Silva Brum
PhD
Federal University of Santa Maria
Lead Author
Gabriela Becker
Federal University of Santa Maria
Lead Author
Sara Marchesan Oliveira
PhD
Federal University of Santa Maria
Lead Author
Topics
- Models: Musculoskeletal