Exploiting BRAF mutations in the therapeutic approach towards oral and maxillofacial tumors

Oral and maxillofacial tumors pose a significant clinical challenge due to their tendency to recur, despite advancements in surgical removal techniques. The jaw's intricate structure further complicates treatments and affects patient quality of life. Consequently, emphasis has shifted towards pharmacological interventions, to potentially reduce invasive surgical procedures. One promising approach targets BRAF mutations, specifically the common V600E mutation. BRAF, a critical protein kinase, regulates cell growth and differentiation via the RAS-RAF-MEK-ERK-MAP kinase pathway. A specific nucleotide change at position 1799, swapping Thymine (T) for Adenine (A), results in the V600E mutation, causing unchecked cell growth. This mutation is common in certain oral and maxillofacial tumors like ameloblastoma. A recent neoadjuvant therapy targeting BRAF, involving the use of dabrafenib and trametinib, has showcased a promising, safe, and effective strategy for organ preservation in the treatment of mandibular ameloblastoma. This convergence of molecular insights and targeted therapies holds the key to managing BRAF-mutated oral and maxillofacial tumors effectively, promising improved patient outcomes.

Clinical Significance and Roles in Angiogenesis of Circulating Microparticles in Oral Cancer

Our recent study established the increased circulating microparticles (MPs) and their procoagulant activity in oral squamous cell carcinoma (OSCC). In the present study, we further evaluated different phenotypes of circulating MPs in OSCC patients and explored their clinical significance and effects on angiogenesis (a critical event in tumor progression). To conduct the study, circulating MPs in 45 OSCC patients and 18 healthy volunteers were characterized and quantified by transmission electron microscopy and flow cytometry. Correlations between circulating MPs and clinicopathologic data, microvessel density, and proangiogenic factor levels in patients with OSCC were analyzed by immunohistochemistry and Spearman rank correlation test. Additionally, the in vitro studies were performed with use of human umbilical vein endothelial cells. Our results showed that the levels of circulating MPs as well as the subsets of platelet-derived, endothelium-derived, and pan-leukocyte MPs in stages III to IV OSCC were significantly higher than stages I to II and healthy subjects. Moreover, these increased circulating MPs were significantly correlated with tumor size, TNM stages, microvessel density, and expression levels of vascular endothelial growth factor (VEGF) and matrix metallopeptidase 9 (MMP9) in OSCC patients. The in vitro studies revealed that circulating MPs isolated from OSCC patients could be effectively taken up by human umbilical vein endothelial cells and could promote the proliferation, migration, invasion, and tube formation of recipient endothelial cells, accompanied by increased expression of proangiogenic factors. In summary, circulating MPs play important roles in angiogenesis and local tumor progression of OSCC. Our results shed new light on the progression of OSCC and might be helpful to explore novel treatment strategies targeting tumor angiogenesis.

Elevated Level of Circulating Platelet-derived Microparticles in Oral Cancer

Numerous studies have demonstrated that circulating microparticles (MPs) play important roles in a variety of diseases (e.g., atherosclerosis, hypertension, and diabetes), but the association between circulating MPs and oral squamous cell carcinoma (OSCC) remains largely unknown. In the present study, the circulating platelet-derived MPs (PMPs) in 63 patients with OSCC, 22 patients with infected keratocystic odontogenic tumor, and 31 healthy volunteers were characterized and quantified by flow cytometric analysis. The coagulation function of patients with OSCC was correspondingly evaluated. Meanwhile, the inflammation-related cytokines were detected in plasma by enzyme-linked immunosorbent assay and in tumor tissues by immunohistochemistry. Our results showed that the plasma level of circulating PMPs was significantly higher in OSCC patients compared with healthy volunteers and patients with infected keratocystic odontogenic tumor, and they showed positive correlation with the increased level of fibrinogen. Moreover, the coagulation time was significantly shorter after the MPs were added to the MP-free plasma. Most important, the levels of interleukin 6 and tumor necrosis factor α in plasma and tumor tissues were significantly increased in OSCC patients, which were closely correlated with the elevated level of circulating PMPs. In summary, this study suggests that the elevated level of circulating PMPs, showing close correlation with the secretion of inflammation-related factors, may contribute to the increased procoagulant activity in patients with OSCC.