Aromatase inhibitors evoke periorbital allodynia in mice via calcitonin gene-related peptide and its receptors in Schwann cells

Submitted: 24 March 2024
Accepted: 20 May 2024
Published: 18 June 2024
Abstract Views: 356
PDF: 145
Publisher's note
All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.


Background: Treatment with the currently recommended aromatase inhibitors (AIs) for adjuvant endocrine treatment of estrogen receptorpositive breast cancer is associated with debilitating musculoskeletal pain symptoms (AIMS) and headache. Recent evidence suggests that the proalgesic channel transient receptor potential ankyrin 1 (TRPA1) is implicated in AIMS. Here, we investigated the cellular and molecular mechanisms, including TRPA1, implicated in periorbital mechanical allodynia (PMA), a surrogate of headache-like pain, evoked by AIs in mice.
Methods: C57BL6/J mice were treated with intragastric letrozole (0.05-0.5 mg/kg), exemestane (1-5 mg/kg) or anastrozole (0.02-0.2 mg/kg) and were evaluated by applying von Frey filaments to the periorbital region over the rostral portion of the eye. Some mice were pretreated (subcutaneous in the periorbital area) with receptor, channel, or enzyme inhibitors. PMA was also investigated in mice with selective silencing of Trpa1 and receptor activity modifying protein 1 [Ramp1, the component of calcitonin gene related peptide (CGRP) receptor required for its functioning] in Schwann cells (Plp-Cre+-Trpa1fl/fl and Plp-Cre+-Ramp1fl/fl mice, respectively) or trigeminal neurons (Adv-Cre+- Trpa1fl/fl and Adv- Cre+- Ramp1fl/fl mice, respectively).
Results: Letrozole dose-dependently produced PMA that was attenuated by a TRPA1 antagonist (A967079) or a CGRP receptor antagonist (olcegepant), whereas indomethacin was ineffective. Selective silencing of Trpa1 in both Schwann cells and trigeminal neurons reduced letrozole- evoked PMA. Silencing of Ramp1 in Schwann cells, but not in trigeminal neurons, attenuated PMA. Inhibition of the intracellular pathway known to promote PMA by CGRP action in Schwann cells, including adenylyl cyclase (SQ-22536), nitric oxide synthase (L-NG-Nitro arginine methyl ester), and oxidative stress (N-tert-butyl-a-phenylnitrone) inhibitors reduced letrozole-evoked PMA. PMA evoked by exemestane (1, 5, 10 mg/kg i.g.) or anastrozole (0.02, 0.1, 0.2 mg/kg i.g.) Was also markedly reduced in mice with selective silencing of TRPA1 in Schwann cells and nociceptors.
Conclusions: Data indicate that letrozole, targeting TRPA1 in peptidergic nerve terminals, releases CGRP that engages its receptor in adjacent Schwann cells to trigger a complex intracellular pathway that results in TRPA1 activation and the ensuing ROS release to sustain PMA. Should these mechanisms be present in patients, their inhibition may ameliorate cephalic mechanical allodynia associated with aromatase inhibitors-induced headaches.



PlumX Metrics


Download data is not yet available.


Gibson L, Lawrence D, Dawson C, Bliss J. Aromatase inhibitors for treatment of advanced breast cancer in postmenopausal women. Cochrane Database Syst Rev. 2009;2009(4):CD003370.
Crew KD, Greenlee H, Capodice J, Raptis G, Brafman L, Fuentes D, et al. Prevalence of joint symptoms in postmenopausal women taking aromatase inhibitors for early-stage breast cancer. J Clin Oncol. 2007;25(25):3877-83. DOI:
Connor C, Attai D. Adjuvant endocrine therapy for the surgeon: options, side effects, and their management. Ann Surg Oncol. 2013;20(10):3188-93. DOI:
Laroche F, Coste J, Medkour T, Cottu PH, Pierga JY, Lotz JP, et al. 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. 2014;15(3):293-303. DOI:
Bhattacharya MR, Bautista DM, Wu K, Haeberle H, Lumpkin EA, Julius D. Radial stretch reveals distinct populations of mechanosensitive mammalian somatosensory neurons. Proc Natl Acad Sci U S A. 2008;105(50):20015-20. DOI:
Palmieri C, Stein RC, Liu X, Hudson E, Nicholas H, Sasano H, et al. IRIS study: a phase II study of the steroid sulfatase inhibitor Irosustat when added to an aromatase inhibitor in ER-positive breast cancer patients. Breast Cancer Res Treat. 2017;165(2):343-53. DOI:
Mao JJ, Chung A, Benton A, Hill S, Ungar L, Leonard CE, et al. Online discussion of drug side effects and discontinuation among breast cancer survivors. Pharmacoepidemiol Drug Saf. 2013;22(3):256-62. DOI:
Din OS, Dodwell D, Wakefield RJ, Coleman RE. Aromatase inhibitor-induced arthralgia in early breast cancer: what do we know and how can we find out more? Breast Cancer Res Treat. 2010;120(3):525-38. DOI:
Nabholtz JM. Long-term safety of aromatase inhibitors in the treatment of breast cancer. Ther Clin Risk Manag. 2008;4(1):189-204. DOI:
Fusi C, Materazzi S, Benemei S, Coppi E, Trevisan G, Marone IM, et al. Steroidal and non-steroidal third-generation aromatase inhibitors induce pain-like symptoms via TRPA1. Nat Commun. 2014;5:5736. DOI:
De Logu F, Tonello R, Materazzi S, Nassini R, Fusi C, Coppi E, et al. TRPA1 Mediates Aromatase Inhibitor-Evoked Pain by the Aromatase Substrate Androstenedione. Cancer Res. 2016;76(23):7024-35. DOI:
Liu H, Talalay P. Relevance of anti-inflammatory and antioxidant activities of exemestane and synergism with sulforaphane for disease prevention. Proc Natl Acad Sci U S A. 2013;110(47):19065-70. DOI:
Brône B, Peeters PJ, Marrannes R, Mercken M, Nuydens R, Meert T, et al. Tear gasses CN, CR, and CS are potent activators of the human TRPA1 receptor. Toxicol Appl Pharmacol. 2008;231(2):150-6. DOI:
De Logu F, Nassini R, Hegron A, Landini L, Jensen DD, Latorre R, et al. Schwann cell endosome CGRP signals elicit periorbital mechanical allodynia in mice. Nat Commun. 2022;13(1):646. DOI:
De Logu F, Nassini R, Materazzi S, Carvalho Goncalves M, Nosi D, Rossi Degl'Innocenti D, et al. Schwann cell TRPA1 mediates neuroinflammation that sustains macrophage-dependent neuropathic pain in mice. Nat Commun. 2017;8(1):1887. DOI:
Edvinsson L, Haanes KA, Warfvinge K, Krause DN. CGRP as the target of new migraine therapies - successful translation from bench to clinic. Nat Rev Neurol. 2018;14(6):338-50. DOI:
Ashina H. Migraine. N Engl J Med 2020;383:10. DOI:
De Logu F, Marini M, Landini L, Souza Monteiro de Araujo D, Bartalucci N, Trevisan G, et al. Peripheral Nerve Resident Macrophages and Schwann Cells Mediate Cancer-induced Pain. Cancer Res. 2021.
Landini L, Marini M, Souza Monteiro de Araujo D, Romitelli A, Montini M, Albanese V, et al. Schwann cell insulin-like growth factor receptor type-1 mediates metastatic bone cancer pain in mice. Brain Behav Immun. 2023;110:348-64. DOI:
Oballa RM, Truchon JF, Bayly CI, Chauret N, Day S, Crane S, et al. A generally applicable method for assessing the electrophilicity and reactivity of diverse nitrile-containing compounds. Bioorg Med Chem Lett. 2007;17(4):998-1002. DOI:
. Headache Classification Committee of the International Headache Society (IHS) The International Classification of Headache Disorders, 3rd edition. Cephalalgia. 2018;38(1):1-211.
Lipton RB, Bigal ME, Ashina S, Burstein R, Silberstein S, Reed ML, et al. Cutaneous allodynia in the migraine population. Ann Neurol. 2008;63(2):148-58. DOI:
Burstein R, Yarnitsky D, Goor-Aryeh I, Ransil BJ, Bajwa ZH. An association between migraine and cutaneous allodynia. Annals of Neurology. 2000;47(5):614-24. DOI:<614::AID-ANA9>3.0.CO;2-N
De Logu F, De Pra SD, de David Antoniazzi CT, Kudsi SQ, Ferro PR, Landini L, et al. Macrophages and Schwann cell TRPA1 mediate chronic allodynia in a mouse model of complex regional pain syndrome type I. Brain Behav Immun. 2020;88:535-46. DOI:
De Logu F, Landini L, Janal MN, Li Puma S, De Cesaris F, Geppetti P, et al. Migraine-provoking substances evoke periorbital allodynia in mice. J Headache Pain. 2019;20(1):18. DOI:
De Logu F, Li Puma S, Landini L, Portelli F, Innocenti A, de Araujo DSM, et al. Schwann cells expressing nociceptive channel TRPA1 orchestrate ethanol-evoked neuropathic pain in mice. J Clin Invest. 2019;129(12):5424-41. DOI:
Guan Z, Kuhn JA, Wang X, Colquitt B, Solorzano C, Vaman S, et al. Injured sensory neuron-derived CSF1 induces microglial proliferation and DAP12-dependent pain. Nat Neurosci. 2016;19(1):94-101. DOI:
Zurborg S, Piszczek A, Martinez C, Hublitz P, Al Banchaabouchi M, Moreira P, et al. Generation and characterization of an Advillin-Cre driver mouse line. Mol Pain. 2011;7(66):66. DOI:
Faul F, Erdfelder E, Lang AG, Buchner A. G*Power 3: a flexible statistical power analysis program for the social, behavioral, and biomedical sciences. Behav Res Methods. 2007;39(2):175-91. DOI:
Kilkenny C, Browne WJ, Cuthill IC, Emerson M, Altman DG. Improving bioscience research reporting: the ARRIVE guidelines for reporting animal research. PLoS Biol. 2010;8(6):e1000412.
Zimmermann M. Ethical guidelines for investigations of experimental pain in conscious animals. Pain. 1983;16(2):109-10. DOI:
Harriott AM, Strother LC, Vila-Pueyo M, Holland PR. Animal models of migraine and experimental techniques used to examine trigeminal sensory processing. J Headache Pain. 2019;20(1):91. DOI:
Chaplan SR, Bach FW, Pogrel JW, Chung JM, Yaksh TL. Quantitative assessment of tactile allodynia in the rat paw. J Neurosci Methods. 1994;53(1):55-63. DOI:

How to Cite

Marini M, Souza Monteiro de Araujo D, Chieca M, Bellantoni E, de Siena G, Mastricci A, Scuffi I, Tesi M, Pensieri P, Nassini R, De Logu F, Landini L. Aromatase inhibitors evoke periorbital allodynia in mice via calcitonin gene-related peptide and its receptors in Schwann cells. Confinia Cephalal [Internet]. 2024 Jun. 18 [cited 2024 Jul. 25];34(1). Available from: