Cisplatin resistance remains a major therapeutic barrier in head and neck squamous cell carcinoma (HNSCC). One mechanism contributing to chemoresistance is enhanced drug efflux mediated by ATP-binding cassette (ABC) transporters, which lower intracellular drug accumulation. Bitter taste receptor 10 (TAS2R10, also called T2R10) has been implicated in regulation of ABC transporters in other contexts. The source study tested whether T2R10 activation or altered expression influences cisplatin sensitivity in HNSCC models and whether modulation of TAS2R10 affects expression of chemoresistance-associated transporters, particularly ABCG2.
The authors frame TAS2R10 as a potential regulator of transporter-mediated chemoresistance and examine both pharmacologic activation (with caffeine) and genetic manipulation of TAS2R10 to probe relationships with transporter expression and cisplatin responsiveness.
The investigators exposed multiple HNSCC cell lines to the T2R10 agonist caffeine at 100 or 200 μM, to cisplatin, or to combinations of caffeine and cisplatin. Cell viability following treatment was assessed using crystal violet assays. This provided a functional readout of whether caffeine exposure influenced cisplatin-associated cytotoxicity across different cell lines.
In parallel, the study evaluated TAS2R10 promoter activity using a promoter-driven mCherry reporter and measured TAS2R10 expression by RT-qPCR following caffeine exposure. ABC transporter expression after caffeine treatment and following genetic perturbation of TAS2R10 (knockdown or overexpression) was measured to connect receptor modulation with transporter gene expression.
Caffeine exposure increased TAS2R10 promoter activity as detected with the mCherry reporter and led to higher TAS2R10 mRNA levels by RT-qPCR. The authors therefore report that pharmacologic activation with caffeine is associated with transcriptional upregulation of TAS2R10 in the models tested.
Concomitant with increased TAS2R10 expression after caffeine treatment, expression of the transporter ABCG2 decreased. The source links these expression changes temporally to caffeine exposure, suggesting a pathway by which T2R10 activation may influence transporter levels.
To evaluate causality, the study performed genetic manipulations of TAS2R10. Knockdown of TAS2R10 (TAS2R10 gene silencing) resulted in increased expression of ABCG2 and ABCF1. Conversely, forced overexpression of TAS2R10 reduced expression of ABCG2 and ABCC1.
These reciprocal changes support a model in which TAS2R10 expression negatively regulates certain ABC transporters associated with chemoresistance, most notably ABCG2 in the reported experiments.
Caffeine enhanced cisplatin-associated reductions in viability in a cell line– and concentration-dependent manner. The strongest enhancement was observed in the UM-SCC47 cell line. FaDu cells showed a significant enhancement only at 200 μM caffeine, while RPMI 2650 exhibited minimal response to caffeine plus cisplatin.
Baseline TAS2R10 expression varied across cell lines; RPMI 2650 and FaDu had lower baseline TAS2R10 expression. Notably, RPMI 2650 cells did not show caffeine-enhanced cisplatin sensitivity, which the authors relate to their low baseline TAS2R10 expression. These results indicate that the impact of T2R10 activation on cisplatin sensitivity is context dependent and may require sufficient baseline expression or inducibility of TAS2R10.
The investigators used The Cancer Genome Atlas (TCGA) data accessed via GEPIA2 to explore clinical associations. High tumor TAS2R10 expression was associated with improved disease-free survival (log-rank p = 0.0071; hazard ratio = 0.61). There was no significant association reported between TAS2R10 expression and overall survival in the analysis presented.
This correlative finding in TCGA complements the mechanistic cell line data, suggesting that higher TAS2R10 expression in tumors may relate to reduced recurrence risk, though causality and clinical applicability were not established in the source report.
Implications: The data support a model in selected preclinical HNSCC models where activation or increased expression of TAS2R10 reduces expression of chemoresistance-associated transporters, particularly ABCG2, and enhances sensitivity to cisplatin. If validated and extended, modulation of T2R10 or downstream pathways could represent a strategy to overcome transporter-mediated chemoresistance.
Limitations reported or evident from the source: the work is preclinical and conducted in cell lines; experimental details beyond those summarized (for example, full concentration–response curves, in vivo validation, or broader profiling of transporter activity) were not reported in the source text. The article is a preprint and has not undergone peer review. The association with TCGA disease-free survival is correlative and does not prove causation.
Next steps that follow from the reported data (not claimed outcomes): validation in additional models, mechanistic dissection of the signaling linking T2R10 to ABC transporter regulation, assessment of transporter function (not only expression), and in vivo studies to determine whether TAS2R10 modulation alters cisplatin response in tumor models would be appropriate. Clinical translation would require much more evidence, including safety and feasibility of any proposed T2R10-targeting approach.
Overall, the source study presents preclinical evidence that TAS2R10 activation or expression correlates with lower ABCG2 expression and enhanced cisplatin sensitivity in selected HNSCC cell lines, and that higher tumor TAS2R10 expression is associated with improved disease-free survival in TCGA analyses. These findings are hypothesis-generating and require further validation.