Metformin Combined with 4SC-202 Inhibited the Migration and Invasion of OSCC via STAT3/TWIST1

Effect and mechanism of resveratrol on ferroptosis mediated by p53/SLC7A11 in oral squamous cell carcinoma

OBJECTIVE

Resveratrol (Res) is a natural phytoestrogen with antitumor activity. This study sought to investigate the role of Res in ferroptosis in oral squamous cell carcinoma (OSCC).

METHODS

Normal human oral keratinocyte (HOK)/oral OSCC (CAL-27/SCC-9) cell lines were treated with different doses of Res. Res toxicity was determined by MTT assay, with half maximal inhibitory concentration values of Res on CAL-27 and SCC-9 cells calculated. Cell viability/colony formation efficiency/migration/invasion/cycle were assessed by CCK-8/colony formation assay/transwell assay/flow cytometry. The expression of p53 protein in the nucleus and cytoplasm, glutathione peroxidase 4 (GPX4) expression, and SLC7A11 messenger RNA (mRNA) and protein expression levels were determined by Western blot and RT-qPCR. Fe2+ content, reactive oxygen species (ROS) level, reduced glutathione (GSH), and lactate dehydrogenase (LDH) release were assessed.

RESULTS

Medium- to low-dose Res had no toxic effect on HOK cells, while high-dose Res markedly reduced HOK cell viability. Res significantly suppressed the viability of OSCC cells (CAL-27 and SCC-9). Res inhibited OSCC cell colony formation/migration/invasion, and induced G1 phase arrest. Res caused the translocation of p53 protein to the nucleus, obviously increased Fe2+ content, ROS level and LDH release, decreased GSH content and GPX4 protein expression, and induced ferroptosis. Down-regulation of p53 partially reversed the inhibitory effects of Res on CAL-27 cell malignant behaviors. Res inhibited SLC7A11 transcription by promoting p53 entry into the nucleus. SLC7A11 overexpression negated the the regulatory effects of p53 knockout on the role of Res in OSCC cell malignant behaviors and ferroptosis.

CONCLUSION

Res accelerated ferroptosis and inhibited malignant behaviors in OSCC cells by regulating p53/SLC7A11.

Targeting histone deacetylases in head and neck squamous cell carcinoma: molecular mechanisms and therapeutic targets

The onerous health and economic burden associated with head and neck squamous cell carcinoma (HNSCC) is a global predicament. Despite the advent of novel surgical techniques and therapeutic protocols, there is an incessant need for efficacious diagnostic and therapeutic targets to monitor the invasion, metastasis and recurrence of HNSCC due to its substantial morbidity and mortality. The differential expression patterns of histone deacetylases (HDACs), a group of enzymes responsible for modifying histones and regulating gene expression, have been demonstrated in neoplastic tissues. However, there is limited knowledge regarding the role of HDACs in HNSCC. Consequently, this review aims to summarize the existing research findings and explore the potential association between HDACs and HNSCC, offering fresh perspectives on therapeutic approaches targeting HDACs that could potentially enhance the efficacy of HNSCC treatment. Additionally, the Cancer Genome Atlas (TCGA) dataset, CPTAC, HPA, OmicShare, GeneMANIA and STRING databases are utilized to provide supplementary evidence on the differential expression of HDACs, their prognostic significance and predicting functions in HNSCC patients.

The mechanisms of action of metformin on head and neck cancer in the pre-clinical setting: a scoping review

This scoping review identifies the mechanistic pathways of metformin when used to treat head and neck cancer cells, in the pre-clinical setting. Understanding the underlying mechanisms will inform future experimental designs exploring metformin as a potential adjuvant for head and neck cancer. This scoping review was conducted according to the Joanna-Briggs Institute framework. A structured search identified 1288 studies, of which 52 studies fulfilled the eligibility screen. The studies are presented in themes addressing hallmarks of cancer. Most of the studies demonstrated encouraging anti-proliferative effects in vitro and reduced tumor weight and volume in animal models. However, a few studies have cautioned the use of metformin which supported cancer cell growth under certain conditions.

Research Progress of Metformin in the Treatment of Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is one of the most common malignancies and has a high mortality, posing a great threat to both human physical and mental health. With the advancement of scientific research, a variety of cancer therapies have been used for OSCC treatment. However, the prognosis of OSCC shows no significant improvement. Metformin has been recognized as the first-line drug for the treatment of diabetes, and recent studies have shown that metformin has a remarkable suppressive effect on tumor progression. Metformin can not only affect the energy metabolism of tumor cells but also play an antitumor role by modulating the tumor microenvironment and cancer stem cells. In this review, the molecular mechanism of metformin and its anticancer mechanism in OSCC are summarized. In addition, this article summarizes the side effects of metformin and the future prospects of its application in the treatment of OSCC.

Oral Cavity Squamous Cell Carcinoma: An Update of the Pharmacological Treatment

Oral cavity squamous cell carcinoma (OCSCC) represents a serious health and socio-economic problem in different geographical areas of the world. It is characterized by a high rate of mortality, recurrence and metastasis. Despite the therapeutic strategies implemented for its management and resolution, currently the survival estimate for locally advanced disease is about 50%. The available therapeutic options comprise surgery and pharmacological treatment. Recently, an increased emphasis has been placed on the drugs that might be of benefit in this life-threatening disease. Therefore, the aim of this present review was to offer a general survey of the current available pharmacological treatment for OCSCC. The PubMed database was used to retrieve the papers using "OCSCC" as the search terms. We limited our search to the last 5 years to give a more updated and recent picture of the state of the art, including preclinical and clinical investigations. We found that 77 out of 201 papers were on the surgical treatment of OCSCC, 43 out of 201 focused on the radiotherapy and 81 out of 201 underwent evaluation for the aim of our review. We excluded the case reports, editorial letters, observational studies and papers written in languages other than English. A total of 12 articles were included in the final review. Our results showed that nanotechnologies use to enhance the efficacy of anticancer drugs such as: cisplatin, paclitaxel, cetuximab, EGFR antagonists, MEK1/2 and immune check inhibitors combination could have promising anti-cancer activity. However, the paucity of available data on drugs suggests the urgent need to improve the pharmacological armamentarium for OCSCC treatment.

STAT3 as a therapeutic target in the metformin-related treatment

Signal transducers and activators of transcription 3 (STAT3) signaling plays an important role in mediating tumor progression, inflammation, cardiovascular disease, and other pathological processes.In recent years, STAT3 as a therapeutic target has received extensive attention. It is well known that metformin can play the role of hypoglycemia by activating AMP-activated protein kinase (AMPK) through inhibition of mitochondrial ATP production.However, AMPK is not required for metformin activity.Although the application of STAT3 as a therapeutic target of metformin is still in the initial research stage, the importance of STAT3 in the mechanism of metformin is gradually being recognizedand further studies are needed to demonstrate the important role of the STAT3 regulatory network in the regulation of diseases by metformin. Here, we reviewed in detail that metformin inhibits the progression of various diseases like tumors, autoimmune diseases and hormone-related diseases by regulating multiple signaling pathways such as JAK/STAT3 and mTOR/STAT3 signaling centered on STAT3. We also summarized recent advances of STAT3 inhibitors combined with metformin in the treatment of diseases.We emphasized that STAT3 signaling, as an AMPK-independent signaling pathway, may be an important target for metformin in clinical therapy.

Metformin inhibits oral squamous cell carcinoma progression through regulating RNA alternative splicing

AIMS

Oral squamous cell carcinoma (OSCC) is considered as the sixth most common cancer worldwide characterized by high invasiveness, high metastasis rate and high mortality. It is urgent to explore novel therapeutic strategies to overcome this feature. Metformin is currently a strong candidate anti-tumor drug in multiple cancers. However, whether metformin could inhibit cancer progression by regulating RNA alternative splicing remains largely unknown.

MAIN METHODS

Cell proliferation and growth ability of CAL-27 and UM-SCC6 were analyzed by CCK8 and colony formation assays. Cell migration was judged by wound healing assay. Mechanistically, RNA-seq was applied to systematically identify genes that are regulated by metformin. The expression of metformin-regulated genes was determined by real-time quantitative PCR (RT-qPCR). Metformin-regulated alternative splicing events were confirmed by RT-PCR.

KEY FINDINGS

We demonstrated that metformin could significantly inhibit the proliferation and migration of oral squamous cell carcinoma cells. Mechanistically, in addition to transcriptional regulation, metformin induces a wide range of alternative splicing alteration, including genes involved in centrosome, cellular response to DNA damage stimulus, GTPase binding, histone modification, catalytic activity, regulation of cell cycle process and ATPase complex. Notably, metformin specifically modulates the splicing of NUBP2, a component of the cytosolic iron-sulfur (Fe/S) protein assembly (CIA). Briefly, metformin favors the production of NUBP2-L, the long splicing isoform of NUBP2, thereby inhibiting cancer cell proliferation.

SIGNIFICANCE

Our findings provide mechanistic insights of metformin on RNA alternative splicing regulation, thus to offer a potential novel route for metformin to inhibit cancer progression.

Relationship of biglycan and decorin expression with clinicopathological features and prognosis in patients with oral squamous cell carcinoma

OBJECTIVE

This study focused on investigating relation between biglycan (BGN) and decorin (DCN) expression and prognostic outcome for oral squamous cell carcinoma (OSCC) cases.

MATERIAL AND METHODS

BGN and DCN mRNA and protein expression was detected by qRT-PCR and Western-blotting (WB) assays from 31 OSCC samples as well as healthy samples. This work harvested 101 paraffin-embedded OSCC together with 30 healthy samples, and conducted immunohistochemical (IHC) staining for assessing pathological changes. Association of DCN with BGN within OSCC was explored by Spearman's analysis. Survival rate was explored by Kaplan-Meier (KM) approach. Multivariate analysis was conducted by Cox regression.

RESULTS

WB and qRT-PCR results showed BGN up-regulation (p < 0.001, p < 0.0001) whereas DCN down-regulation (p < 0.0001, p < 0.0001) with fresh OSCC tissues; the expression of BGN and DCN associated with the OSCC histopathological grade. IHC results suggested elevated BGN level (p < 0.0001) whereas DCN down-regulation (p < 0.0001) with paraffin embedded OSCC tissues. The expression of BGN and DCN associated with histopathologic grades and tumor stage of OSCC. The result of Spearman's analysis demonstrated significant association between the expression of BGN and DCN in OSCC. Survival analysis revealed that patients with higher BGN/lower DCN level showed poor overall survival (OS) as well as tumor-specific survival (TSS). Multivariate analysis proved that BGN and DCN independently predicted the prognosis of OS and TSS.

CONCLUSION

BGN and DCN expression levels can be adopted for predicting OSCC prognostic outcome.

Inflammation and Invasion in Oral Squamous Cell Carcinoma Cells Exposed to Electronic Cigarette Vapor Extract

Electronic cigarettes (eCig) represent a new avenue of tobacco exposure that involves heating oil-based liquids and the delivery of aerosolized flavors with or without nicotine, yet little is known about their overall health impact. The oral cavity is an anatomic gateway for exposure that can be compromised by activating myriad of signaling networks. Oral squamous cell carcinoma (OSSC) is a common malignancy affecting 30,000 people in the United States each year. Our objective was to determine the impact of eCig and nicotine on gingival OSSC invasion and their secretion of pro-inflammatory molecules. Gingiva-derived Ca9-22 cells and tongue-derived Cal27 cells were exposed to eCig vapor extract (EVE) generated from Red Hot or Green Apple (Apple) flavored eCig solution +/- nicotine for 6 hours. Isolation of protein lysates and collection conditioned media was done after treatment. Real-time cellular invasion was assessed using a RTCA DP instrument. Protein expression was determined using western blot. Compared to controls, we observed: elevated NF-kB, TNF-α, ERK, JNK, MMP-13 and cell invasion by Ca9-22 treated with Apple EVE; increased TNF-α and JNK by Ca9-22 treated with Red Hot EVE; and increased TNF-α and JNK by Cal27 cells treated with both Apple and Red Hot EVE. We conclude that eCig flavoring and nicotine orchestrated differential cell invasion and inflammatory effects. This study provides an important initial step in dissecting mechanisms of cancerous invasion and molecular avenues employed by OSCC.

LncRNA LINC01303 Promotes the Progression of Oral Squamous Cell Carcinomas via the miR-429/ZEB1/EMT Axis

Objectives

The aim of this research was to uncover the biological role and mechanisms of LINC01303 in oral squamous cell carcinoma (OSCC).

Materials and Methods

Real-time quantitative PCR (qRT-PCR) was used to determine LINC01303 expression in OSCC tissues. Subcellular distribution of LINC01303 was examined by nuclear/cytoplasmic RNA fractionation and FISH experiments. The role of LINC01303 in the growth of TSCCA and SCC-25 was examined by CCK-8 assay, colony formation, transwell invasion assay in vitro, and xenograft tumor experiment in vivo. Dual-luciferase reporter assay was used to verify the interaction between LINC01303 and miR-429. RNA pull‐down assay was used to discover miR-429‐interacted protein, which was further examined by qRT-PCR, western blot, and rescue experiments.

Results

LINC01303 expression was higher in OSCC tissues compared with adjacent nontumor tissues. LINC01303 was found to be localized in the cytoplasm of OSCC cells. Knockdown of LINC01303 inhibited OSCC cell proliferation and invasion, whereas increasing the expression of LINC01303 showed the opposite effects. Furthermore, LINC01303 served as a miR-429 “sponge” and positively regulated ZEB1 expression. Moreover, LINC01303 promoted OSCC through miR-429/ZEB1 axis both in vivo and in vitro.

Conclusions

LINC01303 plays an oncogenic role in OSCC and is a promising biomarker for OSCC patients.

METTL3 Intensifies the Progress of Oral Squamous Cell Carcinoma via Modulating the m6A Amount of PRMT5 and PD-L1

N6-Methyladenosine (m6A) modification is one of the commonest chemical modifications in eukaryotic mRNAs, which has essential effects on mRNA translation, splicing, and stability. Currently, there is a rising concern on the regulatory role of m6A in tumorigenesis. As a known component in the m6A methyltransferase complex, METTL3 (methyltransferase-like 3) plays an essential role in m6A methylation. Till now, the functions of METTL3 in oral squamous cell carcinoma (OSCC) and its relative mechanism remain to be explored. In this research, through the GEPIA database, we found that high METTL3 expression has a correlation with poor prognosis of squamous cell carcinoma of head and neck. qRT-PCR displayed that METTL3 was highly expressed in OSCC cells. Functionally, METTL3 knockdown reduced the invasion, migration, and proliferation competence of OSCC cells and attenuated the activation of CD8+ T cells. In contrast, METTL3 overexpression resulted in opposite results. GEPIA, UALCAN, and SRAMP databases, PCR, western blot, and m6A RNA methylation assay confirmed the m6A modification of PRMT5 and PD-L1 mediated by METTL3. In conclusion, our results displayed that METTL3 intensified the metastasis and proliferation of OSCC by modulating the m6A amounts of PRMT5 and PD-L1, suggesting that METTL3 may be a therapeutic target for OSCC patients.

Overexpression of T-type calcium channel Cav3.1 in oral squamous cell carcinoma: association with proliferation and anti-apoptotic activity

Cav3.1, a subfamily of T-type calcium channel, is overexpressed in various human cancers and exerts important functions in tumor progression. This study is to identify the expression pattern and clinical significance of Cav3.1 in oral squamous cell carcinoma (OSCC). Firstly, the expression levels of Cav3.1 in oral mucosa (OM), dysplasia and oral squamous cell carcinoma (OSCC) were determined and compared by real-time quantitative PCR and Western blot analysis. After that, human tissue microarrays, containing 29 OM, 23 dysplasia and 122 primary OSCC samples, were applied to investigate the expression levels of Cav3.1, proliferation markers [Ki-67, proliferating cell nuclear antigen (PCNA)] and cellular anti-apoptosis markers [B cell lymphoma 2 (Bcl-2)] by immunohistochemistry and digital pathology analysis. In addition, we determined the function of Cav3.1 using knockdown assays of Cav3.1 in vitro. The results demonstrated that the mRNA and protein expression of Cav3.1 were significantly higher in OSCC specimens, and Cav3.1 expression in primary OSCCs was correlated with tumor size and pathological grade. Statistical analysis of immunohistochemical staining showed that Cav3.1 was closely correlated with Ki-67, PCNA and Bcl-2. Functional studies showed that the knockdown of Cav3.1 in OSCC cell lines using RNA interference influenced cell proliferation and apoptosis in vitro. Taken together, these findings suggested that Cav3.1 is overexpressed in OSCC tissues, also associated with proliferative and anti-apoptotic activity in oral squamous cell carcinoma.