Natural product triptolide induces GSDME-mediated pyroptosis in head and neck cancer through suppressing mitochondrial hexokinase-ΙΙ

Abstract

Background Pyroptosis is a lytic cell death form executed by gasdermins family proteins. Induction of tumor pyroptosis promotes anti-tumor immunity and is a potential cancer treatment strategy. Triptolide (TPL) is a natural product isolated from the traditional Chinese herb which possesses potent anti-tumor activity in human cancers. However, its role in pyroptosis remains to be elucidated. Methods Cell survival was measured by colony formation assay. Cell apoptosis was determined by Annexin V assay. Pyroptosis was evaluated by morphological features and release of interleukin 1β and lactate dehydrogenase A (LDHA). Immunofluorescence staining was employed to measure subcellular localization of proteins. Tumorigenicity was assessed by a xenograft tumor model. Expression levels of mRNAs or proteins were determined by qPCR or western blot assay, respectively. Results Triptolide eliminates head and neck cancer cells through inducing gasdermin E (GSDME) mediated pyroptosis. Silencing GSDME attenuates the cytotoxicity of TPL against cancer cells. TPL treatment suppresses expression of c-myc and mitochondrial hexokinase II (HK-II) in cancer cells, leading to activation of the BAD/BAX-caspase 3 cascade and cleavage of GSDME by active caspase 3. Silencing HK-II sensitizes cancer cells to TPL induced pyroptosis, whereas enforced expression of HK-II prevents TPL induced pyroptosis. Mechanistically, HK-II prevents mitochondrial translocation of BAD, BAX proteins and activation of caspase 3, thus attenuating cleavage of GSDME and pyroptosis upon TPL treatment. Furthermore, TPL treatment suppresses NRF2/SLC7A11 (also known as xCT) axis and induces reactive oxygen species (ROS) accumulation, regardless of the status of GSDME. Combination of TPL with erastin, an inhibitor of SLC7A11, exerts robust synergistic effect in suppression of tumor survival in vitro and in a nude mice model. Conclusions This study not only provides a new paradigm of TPL in cancer therapy, but also highlights a crucial role of mitochondrial HK-II in linking glucose metabolism with pyroptosis.

Long non‑coding RNA nuclear paraspeckle assembly transcript 1 regulates ionizing radiation‑induced pyroptosis via microRNA‑448/gasdermin E in colorectal cancer cells

“…1A ). Flow cytometry analysis revealed that IR dose-dependently increased the percentage of dead cells (double positive for 7-AAD and Annexin V, which provides an approximate quantitative estimate of pyroptotic cells) ( 36 ) at 48 h post-irradiation (P<0.05) ( Fig. 1B ).…”

Development of a prognostic pyroptosis-related gene signature for head and neck squamous cell carcinoma patient

“…Pyroptosis-related gene (PRG) signatures can offer insight into prognostic outcomes across a range of cancer types [ 23 , 24 ]. Treatment with TPL can activate GSDME-mediated pyroptosis by inhibiting the expression of HK-II in the mitochondria in HNSCC [ 25 ]. Although PRGs have been shown to have the prognostic value when predicting HNSCC patient outcomes [ 26 ], PRG-mediated immune infiltration and the aberrant changes in the biological behavior of cancer cells remain poorly understood.…”

Signature Construction and Molecular Subtype Identification Based on Pyroptosis-Related Genes for Better Prediction of Prognosis in Hepatocellular Carcinoma

“…Recent studies have identified pyroptosis as a new form of programmed cell death, which plays an essential role in tumor development and treatment mechanisms [ 8 ]. Pyroptosis has been found to play a crucial role in various cancers, such as non-small-cell lung cancer and head and neck cancer [ 34 , 35 ]. Currently, the pyroptosis-related prognostic signature has been constructed in ovarian cancer and gastric cancer, with an excellent prognostic potential [ 36 , 37 ].…”