The role of NLRP3 inflammasome in 5-fluorouracil resistance of oral squamous cell carcinoma

Abstract

Background5-Fluorouracil (5-FU) is a widely used drug for the therapy of cancer. However, the chemoresistance of tumor cells to 5-FU usually limits its clinical effectiveness. In this study, we explored the role of NLRP3 inflammasome in 5-FU resistance of oral squamous cell carcinoma (OSCC).MethodsThe mRNA and protein expression levels of NLRP3, Caspase1 and IL-1β in resected OSCC specimens or cell lines were measured respectively by quantitative real time-PCR (qRT-PCR) and western blot. NLRP3 and Ki-67 expression in paraffin-embedded OSCC tissues was determined by immunohistochemistry. The correlation between 5-FU treatment and the expression and activation of NLRP3 inflammasome was further examined by evaluating NLRP3 and IL-1β expression in OSCC cell lines without or with NLRP3 knocked down. Cell viabilities of OSCC cells were determined by the MTT assay. Apoptosis and intracellular reactive oxygen species (ROS) of OSCC cells induced by 5-FU were measured by the flow cytometer. The carcinogen-induced tongue squamous carcinoma mice model was established by continuous oral administration of 4-nitroquinoline 1-oxide in wild-type BALB/c, Nlrp3 −/− and Caspase1 −/− mice. Tumor incidence were observed and tumor area were evaluated.ResultsIn the clinical analysis, expression and activation of NLRP3 inflammasome was clearly increased in OSCC tissues of patients who received 5-FU-based chemotherapy. Multivariate Cox regression analysis revealed that this high expression was significantly correlated with tumor stage and differentiation, and was associated with poor prognosis. Moreover, 5-FU treatment increased expression and activation of NLRP3 inflammasome in OSCC cells in a cell culture system and xenograft mouse model. Silencing of NLRP3 expression significantly inhibited OSCC cell proliferation and enhanced 5-FU-induced apoptosis of OSCC cells. Further investigation showed that intracellular ROS induced by 5-FU promoted the expression and activation of NLRP3 inflammasome and increased the production of interleukin (IL)-1β, which then mediated the chemoresistance. With the carcinogen-induced OSCC model, we found less and later tumor incidence in Nlrp3 −/− and Caspase1 −/− mice than wild-type mice. And greater decrease of tumor area was observed in the gene deficient mice treated with 5-FU.ConclusionsOur findings suggest that NLRP3 inflammasome promoted 5-FU resistance of OSCC both in vitro and in vivo, and targeting the ROS/NLRP3 inflammasome/IL-1β signaling pathway may help 5-FU-based adjuvant chemotherapy of OSCC.

MicroRNA‐22 suppresses cell proliferation, migration and invasion in oral squamous cell carcinoma by targeting NLRP3

“…Recently, Zhang et al () reported that miR‐22 could be considered as both a predictor of 5‐FU sensitivity for personalized treatment and a therapeutic target for colorectal cancer (Zhang et al, ). As we previously revealed that the high expression and activation of NLRP3 inflammasome mediated the chemoresistance of OSCC cells to 5‐FU‐based therapy (Feng et al, ), we speculated that it was probably due to the downregulated expression of miR‐22.…”

Mouse Tumor-Bearing Models as Preclinical Study Platforms for Oral Squamous Cell Carcinoma

“…As the tumor model closest to the actual conditions of the human body, the PDX model can provide personalized drug guidance for a single patient and realize precision therapy for a tumor. In the field of OSCC research, xenograft OSCC mouse models are used for screening drugs(137)(138)(139) and studying drug resistance, such as cisplatin (9, 140), 5-fluorouracil(141), and cetuximab(142).…”

Zymosan Promotes Proliferation, Candida albicans Adhesion and IL-1β Production of Oral Squamous Cell Carcinoma In Vitro

“…It is interesting to nd that OSCC cells could secrete pro-in ammatory cytokines (such as IL-1β) and be in uenced by microbiota or their cell components, which indicates a more complex interaction between cancer cells, immune cells and microbiota in tumour microenvironment. Another report from our lab revealed that NLRP3 in ammasomeactivated IL-1β promoted 5-FU resistance in OSCC both in vitro and in vivo [29], and combining these data, it can be inferred that the presence of C. albicans in oral cancer may in uence the effect of chemotherapy by inducing IL-1β production, which was also a potential target for treating oral cancer.…”