Characterization of intracellular Ca 2+ mobilization in gefitinib-resistant oral squamous carcinoma cells HSC-3 and -4

• Published in: International journal of oral biology Vol. 46; no. 4; pp. 176 - 183
• Main Authors: Kim, Mi Seong, Kim, Min Seuk
• Format: Journal Article
• Language: Korean
• Published: 2021
• Subjects: Squamous cell carcinoma of head and neck; Gefitinib; Drug resistance; Calcium channel
• ISSN: 1226-7155; 2287-6618

Oral squamous cell carcinoma (OSCC) metastasis is characterized by distant metastasis and local recurrence. Combined chemotherapy with cisplatin and 5-fluorouracil is routinely used to treat patients with OSCC, and the combined use of gefitinib with cytotoxic drugs has been reported to enhance the sensitivity of cancer cells in vitro. However, the development of drug resistance because of prolonged chemotherapy is inevitable, leading to a poor prognosis. Therefore, understanding alterations in signaling pathways and gene expression is crucial for overcoming the development of drug resistance. However, the altered characterization of Ca2+ signaling in drug-resistant OSCC cells remains unclear. In this study, we investigated alterations in intracellular Ca2+ ([Ca2+]i) mobilization upon the development of gefitinib resistance in human tongue squamous carcinoma cell line (HSC)-3 and HSC-4 using ratiometric analysis. This study demonstrated the presence of altered epidermal growth factor- and purinergic agonist-mediated [Ca2+]i mobilization in gefitinib-resistant OSCC cells. Moreover, Ca2+ content in the endoplasmic reticulum, store-operated calcium entry, and lysosomal Ca2+ release through the transient receptor potential mucolipin 1, were confirmed to be significantly reduced upon the development of apoptosis resistance. Consistent with [Ca2+]i mobilization, we identified modified expression levels of Ca2+ signaling-related genes in gefitinib-resistant cells. Taken together, we propose that the regulation of [Ca2+]i mobilization and related gene expression can be a new strategy to overcome drug resistance in patients with cancer.