PAR2-dependent phosphorylation of TRPV4 at the trigeminal nerve terminals contributes to tongue cancer pain

Crosstalk between calcium and reactive oxygen species signaling in cancer revisited

The homeostasis of cellular reactive oxygen species (ROS) and calcium (Ca2+) are intricately linked. ROS signaling and Ca2+ signaling are reciprocally regulated within cellular microdomains and are crucial for transcription, metabolism and cell function. Tumor cells often highjack ROS and Ca2+ signaling mechanisms to ensure optimal cell survival and tumor progression. Expression and regulation of Ca2+ channels and transporters at the plasma membrane, endoplasmic reticulum, mitochondria and other endomembranes are often altered in tumor cells, and this includes their regulation by ROS and reactive nitrogen species (RNS). Likewise, alterations in cellular Ca2+ levels influence the generation and scavenging of oxidants and thus can alter the redox homeostasis of the cell. This interplay can be either beneficial or detrimental to the cell depending on the localization, duration and levels of ROS and Ca2+ signals. At one end of the spectrum, Ca2+ and ROS/RNS can function as signaling modules while at the other end, lethal surges in these species are associated with cell death. Here, we highlight the interplay between Ca2+ and ROS in cancer progression, emphasize the impact of redox regulation on Ca2+ transport mechanisms, and describe how Ca2+ signaling pathways, in turn, can regulate the cellular redox environment.

TRPV4 activation in Schwann cells mediates mechanically induced pain of oral cancer

Introduction

Patients with oral cancer often experience intense functional pain due to mechanical stimulation at the cancer site. The role of mechanosensitive ion channels in oral cancer pain, such as TRPV4, is not fully understood.

Objectives

Our objective was to investigate the role of Schwann cell TRPV4 in oral cancer pain.

Methods

We examined the impact of TRPV4 inhibition on oral cancer pain in NU/J and C57BL/6J mice injected with human tongue cancer cell line (HSC-3) and mouse oral cancer cell line (MOC2) in the hind paw or tongue. Mechanical and heat sensitivity were assessed using the von Frey and Hargreaves tests, respectively. TRPV4 expression and functional activity in Schwann cells were analyzed using immunohistochemistry, qRT-PCR, Ca2+ imaging, and patch-clamp electrophysiology. The effect of TRPV4 activation on Schwann cell responses to mechanical stimulation was evaluated using a piezo stimulator. Conditioned media (CM) from TRPV4-activated Schwann cells were injected into the mouse paw to evaluate the contribution of TRPV4 in Schwann cells to mechanical hypersensitivity.

Results

TRPV4 inhibition reduced paw cancer mechanical nociception in mice dose-dependently without affecting heat sensitivity. TRPV4 inhibition also decreased facial nociception in tongue cancer mice. TRPV4 was expressed mainly on the plasma membrane of mouse Schwann cells and activation of TRPV4 induced Ca2+ responses and whole-cell membrane currents in human Schwann cells. Mechanoactivated currents in human Schwann cells were inhibited by the TRPV4 antagonist HC-067047. Schwann cell CM induced mechanical hypersensitivity in mice, which was blocked by pre-treatment with HC-067047.

Conclusion

TRPV4 activation plays a role in mediating mechanically induced pain of oral cancer.

TRPV4 Channel in Neurological Disease: from Molecular Mechanisms to Therapeutic Potential

Transient Receptor Potential Vanilloid 4 (TRPV4) is a non-selective cation channel with pivotal roles in various physiological processes, including osmosensitivity, mechanosensation, neuronal development, vascular tone regulation, and bone homeostasis in human bodies. Recent studies have made significant progress in understanding the structure and functional role of TRPV4, shedding light on its involvement in pathological processes, particularly in the realm of neurological diseases. Here, we aim to provide a comprehensive exploration of the multifaceted contributions of TRPV4 to neurological diseases, spanning its intricate molecular mechanisms to its potential as a target for therapeutic interventions. We delve into the structural and functional attributes of TRPV4, scrutinize its expression profile, and elucidate the possible mechanisms through which it participates in the pathogenesis of neurological disorders. Furthermore, we discussed recent years' progress in therapeutic strategies aimed at harnessing TRPV4 for the treatment of these diseases. These insights will provide a basis for understanding and designing modality-specific pharmacological agents to treat TRPV4-associated disorders.

Calcium channels as therapeutic targets in head and neck squamous cell carcinoma: current evidence and clinical trials

Head and neck squamous cell carcinoma (HNSCC) originates from the mucosal epithelium of the oral cavity, pharynx, and larynx, and is marked by high rates of recurrence and metastasis. Calcium signaling is associated with the progression of HNSCC and the development of drug resistance. Changes in calcium ion flow can trigger severe pathophysiological processes, including malignant transformation, tumor proliferation, epithelial-mesenchymal transition, and apoptosis evasion. Calcium channels regulate and facilitate these processes. Remodeling of calcium signaling has become one of the most prevalent adaptive mechanisms in cancer cells. Preclinical and clinical evidence indicates that alterations in calcium signaling are crucial for the progression of HNSCC. This review examines the role of calcium channels in HNSCC development and evaluates current clinical trials targeting these channels to assess the feasibility of calcium signaling-based therapies for HNSCC.

Targeting TRPV4 Channels for Cancer Pain Relief

Despite the unique and complex nature of cancer pain, the activation of different ion channels can be related to the initiation and maintenance of pain. The transient receptor potential vanilloid 4 (TRPV4) is a cation channel broadly expressed in sensory afferent neurons. This channel is activated by multiple stimuli to mediate pain perception associated with inflammatory and neuropathic pain. Here, we focused on summarizing the role of TRPV4 in cancer etiology and cancer-induced pain mechanisms. Many studies revealed that the administration of a TRPV4 antagonist and TRPV4 knockdown diminishes nociception in chemotherapy-induced peripheral neuropathy (CIPN). Although the evidence on TRPV4 channels' involvement in cancer pain is scarce, the expression of these receptors was reportedly enhanced in cancer-induced bone pain (CIBP), perineural, and orofacial cancer models following the inoculation of tumor cells to the bone marrow cavity, sciatic nerve, and tongue, respectively. Effective pain management is a continuous problem for patients diagnosed with cancer, and current guidelines fail to address a mechanism-based treatment. Therefore, examining new molecules with potential antinociceptive properties targeting TRPV4 modulation would be interesting. Identifying such agents could lead to the development of treatment strategies with improved pain-relieving effects and fewer adverse effects than the currently available analgesics.

A Comprehensive Review on the Regulatory Action of TRP Channels: A Potential Therapeutic Target for Nociceptive Pain

The transient receptor potential (TRP) superfamily of ion channels in humans comprises voltage-gated, non-selective cation channels expressed both in excitable as well as non-excitable cells. Four TRP channel subunits associate to create functional homo- or heterotetramers that allow the influx of calcium, sodium, and/or potassium. These channels are highly abundant in the brain and kidney and are important mediators of diverse biological functions including thermosensation, vascular tone, flow sensing in the kidney and irritant stimuli sensing. Inherited or acquired dysfunction of TRP channels influences cellular functions and signaling pathways resulting in multifaceted disorders affecting skeletal, renal, cardiovascular, and nervous systems. Studies have demonstrated the involvement of these channels in the generation and transduction of pain. Based on the multifaceted role orchestrated by these TRP channels, modulation of the activity of these channels presents an important strategy to influence cellular function by regulating intracellular calcium levels as well as membrane excitability. Therefore, there has been a remarkable pharmaceutical inclination toward TRP channels as therapeutic interventions. Several candidate drugs influencing the activity of these channels are already in the clinical trials pipeline. The present review encompasses the current understanding of TRP channels and TRP modulators in pain and pain management.