Extracellular vesicles in oral squamous cell carcinoma: current progress and future prospect

Extracellular vesicles in the pathogenesis and future diagnostics of oral squamous cell carcinoma

Extracellular vesicles are a group of heterogeneous particles secreted during both physiological and pathological conditions which serve in intercellular communication and play a role in the development and progression of oral squamous cell carcinoma, the most common malignant tumor of the head and neck with a high mortality rate. Extensive research is being conducted in order to determine the precise role of extracellular vesicles in oncogenic processes and to explore the possible application of extracellular vesicles as early tumor biomarkers. In this review, we aimed to systematize observed roles extracellular vesicles might play in organizing of tumor microenvironment, tumor invasion and metastasis, as well as the impact of extracellular vesicles on immune dysregulation and development of resistance to chemotherapeutics. Additionally, we summarized findings involving the potential use of extracellular vesicles cargo proteins as early disease biomarkers.

Knockdown of circXPO1 inhibits the development of oral squamous cell carcinoma cells

BACKGROUND

Circular RNAs (circRNAs) have emerged as pivotal regulators of cellular processes in human malignancies, including oral squamous cell carcinoma (OSCC).

METHODS

Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to detect RNA expression levels of circXPO1, miR-524-5p and cyclin D1 (CCND1). Colony formation assay and 5-Ethynyl-2'-deoxyuridine (EdU) assay were performed to analyze cell proliferation, while transwell assay was carried out to investigate the cell migration and invasion. Cell apoptosis was assessed by flow cytometry. Protein expression analysis was implemented by Western blot assay. Additionally, lactate production and glucose consumption were investigated using a lactate assay kit and glucose assay kit, respectively. The in vivo tumorigenic potential of circXPO1 was evaluated using a xenograft mouse model assay.

RESULTS

Elevated levels of circXPO1 and CCND1, alongside reduced miR-524-5p expression were decreased in OSCC tissues and cells. Knockdown of circXPO1 in OSCC cells inhibited their proliferative, migratory and invasive capacities, as well as glycolysis, prompting apoptosis. Moreover, circXPO1 silencing hindered tumor growth in vivo. MiR-524-5p could be sequestered by circXPO1, and its inhibition could counteract the beneficial effects of circXPO1 knockdown on OSCC progression.

CONCLUSION

Knockdown of circXPO1 inhibited OSCC progression by up-regulating miR-524-5p and down-regulating CCND1 expression, which might provide potential targets for OSCC treatment.

Unlocking the Therapeutic Potential of Oral Cancer Stem Cell-Derived Exosomes

Oral cancer (OC) presents a significant global health burden with rising incidence rates. Despite advancements in diagnosis and treatments, the survival rate for OC patients, particularly those with advanced or recurrent disease, remains low at approximately 20%. This poor prognosis is often due to a small population of cancer stem cells (CSCs) that are capable of self-renewal and immune evasion, playing pivotal roles in proliferation, tumor initiation, progression, metastasis, and therapy resistance. Exosomes, which are nano-sized extracellular vesicles (EVs), have emerged as crucial mediators of cell-to-cell communication within the tumor microenvironment (TME). These vesicles carry diverse molecules such as DNA, RNA, proteins, lipids, and metabolites, influencing various cellular processes. Emerging evidence suggests that CSC-derived EVs significantly promote tumor progression and metastasis and maintain the balance between CSCs and non-CSCs, which is vital for intracellular communication within the TME of oral cancer. Recent reports indicate that oral cancer stem cell-derived EVs (OCSC-EVs) influence stemness, immune evasion, metastasis, angiogenesis, tumor reoccurrence, and drug resistance. Understanding OCSC-EVs could significantly improve oral cancer diagnosis, prognosis, and therapy. In this mini-review, we explore OCSC-derived exosomes in oral cancer, examining their potential as diagnostic and prognostic biomarkers that reflect CSC characteristics, and delve into their therapeutic implications, emphasizing their roles in tumor progression and therapy resistance. However, despite their promising potential, several challenges remain, including the need to standardize isolation and characterization methods and to elucidate exosome-mediated mechanisms. Thus, a comprehensive understanding of OCSC-EVs could pave the way for innovative therapeutic strategies that have the potential to improve clinical outcomes for OC patients.

Recent advances in minimally invasive biomarkers of OSCC: from generalized to personalized approach

Oral cancer is the 6th most common type of cancer worldwide, and oral squamous cell carcinoma (OSCC) accounts for >90% of oral cancers. It is a major health problem, particularly in low- and middle-income countries (LMICs), due to both its high incidence and significant mortality and morbidity. Despite being a global burden, and even with the significant advancement in the management of OSCC, the overall outcome of the disease is still abysmal. With the advent of time, advanced diagnostic and treatment approaches have come into practice, but the burden of the disease has not improved significantly. Major reasons attributed to the poor outcome are delay in diagnosis, locoregional recurrence and resistance to the currently available treatment regimen. In this review, we have highlighted the existing challenges in the diagnosis and have emphasized the advancements in minimally invasive biomarkers. Additionally, the importance of collaborative multidimensional approaches involving clinicians and researchers has been discussed, as well as the need to redefine and establish better utility and management of existing diagnostic and treatment protocols along with the minimally invasive/non-invasive biomarkers.

Exosomes: A Cutting-Edge Theranostics Tool for Oral Cancer

Exosomes are a subpopulation of extracellular vesicles (EVs) secreted by cells. In cancer, they are key cellular messengers during cancer development and progression. Tumor-derived exosomes (TEXs) promote cancer progression. In oral cancer, the major complication is oral squamous cell carcinoma (OSCC). Exosomes show strong participation in several OSCC-related activities such as uncontrolled cell growth, immune suppression, angiogenesis, metastasis, and drug and therapeutic resistance. It is also a potential biomarker source for oral cancer. Some therapeutic exosome sources such as stem cells, plants (it is more effective compared to others), and engineered exosomes reduce oral cancer development. This therapeutic approach is effective because of its specificity, biocompatibility, and cell-free therapy (it reduced side effects in cancer treatment). This article highlights exosome-based theranostics signatures in oral cancer, clinical trials, challenges of exosome-based oral cancer research, and future improvements. In the future, exosomes may become an effective and affordable solution for oral cancer.

Cancer-associated fibroblast-derived extracellular vesicles promote lymph node metastases in oral cavity squamous cell carcinoma by encapsulating ITGB1 and BMI1

BACKGROUND

Extracellular vesicles (EVs) have been revealed to facilitate the development of oral squamous cavity cell carcinoma (OCSCC), while its supporting role in lymph node metastases is under continuous investigation. This study aimed to examine the function of cancer-associated fibroblasts (CAF)-derived EVs (CAF-EVs) during lymph node metastasis in OCSCC and the mechanisms.

METHODS

CAF were isolated from OCSCC tissues of patients, and CAF-EVs were extracted and identified. EdU, colony formation, wound healing, and Transwell assays were performed. The OCSCC cells before and after CAF-EVs treatment were injected into mice to probe the effects of CAF-EVs on tumor growth and lymph node metastasis, respectively. The effect of CAF-EVs treatment on transcriptome changes in OCSCC cells was analyzed. Clinical data of patients with OCSCC were analyzed to determine the prognostic significance of the selected genes. Finally, loss-of-function assays were conducted to corroborate the involvement of polycomb complex protein BMI-1 (BMI1) and integrin beta1 (ITGB1).

RESULTS

CAF-EVs promoted the malignant behavior of OCSCC cells and accelerated tumor growth and lymph node metastasis in mice. CAF-EVs significantly increased the expression of BMI1 and ITGB1, and the expression of BMI1 and ITGB1 was negatively correlated with the overall survival and relapse-free survival of OCSCC patients. Knockdown of BMI1 or ITGB1 in OCSCC cells abated the promoting effects of CAF-EVs in vitro and in vivo.

CONCLUSION

CAF-EVs elicited the metastasis-promoting properties in OCSCC by elevating BMI1 and ITGB1, suggesting that BMI1 and ITGB1 could be potential biomarkers and therapeutic targets for OCSCC.