Targeting of FSP1 regulates iron homeostasis in drug-tolerant persister head and neck cancer cells via lipid-metabolism-driven ferroptosis.

BACKGROUND: Research has demonstrated that some tumor cells can transform into drug-tolerant persisters (DTPs), which serve as a reservoir for the recurrence of the disease. The persister state in cancer cells arises due to temporary molecular reprogramming, and exploring the genetic composition and microenvironment during the development of head and neck squamous cell carcinoma (HNSCC) can enhance our comprehension of the types of cell death that HNSCC, thus identifying potential targets for innovative therapies. This project investigated lipid-metabolism-driven ferroptosis and its role in drug resistance and DTP generation in HNSCC. METHODS: High levels of FSP1 were discovered in the tissues of patients who experienced relapse after cisplatin treatment. RNA sequencing indicated that a series of genes related to lipid metabolism were also highly expressed in tissues from these patients. Consistent results were obtained in primary DTP cells isolated from patients who experienced relapse. The Cancer Genome Atlas database confirmed this finding. This revealed that the activation of drug resistance in cancer cells is influenced by FSP1, intracellular iron homeostasis, and lipid metabolism. The regulatory roles of ferroptosis suppressor protein 1 (FSP1) in HNSCC metabolic regulation were investigated. RESULTS: We generated human oral squamous cell carcinoma DTP cells (HNSCC cell line) to cisplatin and observed higher expression of FSP1 and lipid-metabolism-related targets in vitro. The shFSP1 blockade attenuated HNSCC-DTP cell stemness and downregulated tumor invasion and the metastatic rate. We found that cisplatin induced FSP1/ACSL4 axis expression in HNSC-DTPC cells. Finally, we evaluated the HNSCC CSC-inhibitory functions of iFSP1 (a metabolic drug and ferroptosis inducer) used for neo-adjuvant chemotherapy; this was achieved by inducing ferroptosis in a patient-derived xenograft mouse model. CONCLUSIONS: The present findings elucidate the link between iron homeostasis, ferroptosis, and cancer metabolism in HNSCC-DTP generation and acquisition of chemoresistance. The findings may serve as a suitable model for cancer treatment testing and prediction of precision treatment outcomes. In conclusion, this study provides clinically oriented platforms for evaluating metabolism-modulating drugs (FSP1 inhibitors) and new drug candidates of drug resistance and ferroptotic biomarkers.

Ovatodiolide suppresses nasopharyngeal cancer by targeting stem cell-like population, inducing apoptosis, inhibiting EMT and dysregulating JAK/STAT signaling pathway.

BACKGROUND: Treatment for metastatic nasopharyngeal carcinoma (NPC) is challenging. Till now, a truly effective chemotherapy regimen for NPC has not yet been identified. These clinical observations prompted us to investigate a potential drug as alternative option for treating. PURPOSE: This study evaluated the inhibitory effects of Ovatodiolide (Ova), on tumorigenic and cancer stem cell characteristics of NPC cells. METHODS: Two NPC cell lines (NPC-BM1 and NPC-BM2) were used to examine the anticancer effects of Ova and the molecular mechanism underlying these activities by using sulforhodamine B cytotoxicity assay, western blot, immunofluorescence, migration, colony and tumorsphere formation assays. RESULTS: Ova significantly inhibited the viability of BM1 and BM2 cells, downregulated Bcl-xL and Puma, and upregulated Bax/Bad expression levels. Ova dose-dependent suppressed migratory/invasive potential of NPC cells, and reduced ability to form colonies. Ova-induced apoptosis correlated with increased Bax/Bcl-xL ratio while NPC motility and colony formation inhibition were associated with reduced expression of p-FAK, p-PXN, F-actin, and Slug proteins and increased E-cadherin. Furthermore, ova inhibited NPC tumorsphere formation, associated with decreased SOX2, OCT4 and JAK-STAT signaling pathway. Ova also attenuated NPC stem cell tumorigenicity, inhibited tumor growth, and enhanced the sensitivity of NPC cells to cisplatin treatment, in vivo. CONCLUSIONS: Our results demonstrated the anticancer efficacy of Ova in NPC and its potential as a putative inhibitor of JAK2 and STAT3, which are essential in tumorigenesis of NPC. Further development of Ova is encouraged.

Investigation of ovatodiolide, a macrocyclic diterpenoid, as a potential inhibitor of oral cancer stem-like cells properties via the inhibition of the JAK2/STAT3/JARID1B signal circuit.

BACKGROUND: The cancer stem cells (CSCs) have been shown to play key roles in the oral cancer initiation, distant metastasis, the development of chemoresistance and recurrence after treatment. Therefore, the inhibition of oral CSCs has been the target for therapeutic development. PURPOSE: In this study, we investigated the anti-CSCs potential of Ovatodiolide (Ova), a diterpenoid isolate of Anisomeles indica, in vitro and in vivo. METHODS: Oral CSCs were treated with Ova, and the expression of pluripotency factors Oct4, Sox-2, and Nanog were evaluated by western blot. Effect of Ova on self-renewal capacity and clonogenicity were assessed with the sphere formation and clonogenic assay in CSCs model derived from oral cancer cell. The effect of Ova was also investigated in a mouse xenograft model obtained by injecting nude mice with oral CSCs cells. RESULTS: We demonstrated that Ova significantly and dose-dependently suppressed oral cancer cell viability and colony formation; Ova markedly inhibited the ALDH1 activities and reduced the CD44high/ALDHrich cell sub-population. Additionally, Ova suppressed orosphere formation by down-regulating CD133, Klf4, Oct4A, Nanog and JARID1B expression. Furthermore, Ova-mediated anti-cancer effects were associated with the dose-dependent reduction in the expression levels of STAT3, p-STAT3, pJAK2, pAKT and pERK1/2 protein. Moreover, Ova synergistically enhanced the anticancer effect of cisplatin against the SAS, FaDu, HSC-3 and TW2.6 orospheres. Ova significantly attenuated the tumor-initiating potential of orosphere in mouse xegnograft model. CONCLUSION: These results demonstrate that Ova effectively suppressed oral tumorigenesis and stemness properties via JAK2/STAT3 signaling. Ova may be considered for future clinical usage.