Apigenin suppresses the low oxaliplatin-induced epithelial-mesenchymal transition in oral squamous cell carcinoma cells via LINC00857.

Background: Apigenin is a natural flavonoid compound with proven antitumor activity. However, its precise underlying pharmacological mechanism remains unclear. Oxaliplatin (OXA) is commonly utilized for cancer treatment as a platinum-based chemotherapy drug. However, the utilization of low-dose OXA carries the risk of inducing epithelial-mesenchymal transition (EMT) in cancer cells and promoting tumor metastasis, thereby giving rise to potential side effects. The purpose of this study is to investigate the synergistic inhibitory effect of apigenin and OXA and its potential mechanism. Methods: HSC-3 cells of oral squamous carcinoma cells (OSCCs) were divided into control, apigenin-treated and co-treated groups. A wound healing assay was conducted to assess alterations in cellular motility and migration, an invasion assay was performed to assess invasiveness, and a three-dimensional culture assay was employed to evaluate angiogenic capacity. Cultured cells were utilized for total DNA extraction, followed by reverse transcription. Relative RNA levels were obtained, and quantitative polymerase chain reaction (qPCR) analysis was conducted to assess the efficiency of LINC00857 expression. Results: The administration of a low dose of OXA promoted the migratory, invasive, and angiogenic capabilities of HSC-3 cells, while also regulating EMT-associated molecular markers to facilitate the process of EMT. The inhibitory impact on OSCC proliferation was enhanced by the synergistic effect of apigenin and OXA. Furthermore, the tumor-promoting effects induced by low-dose OXA were notably suppressed through LINC00857. Conclusions: Evidence from this study indicates that apigenin can effectively suppress the metastasis of OSCC cancer cells induced by low-dose OXA through inhibiting the level of LINC00857, suggesting a promising therapeutic strategy.

Pathogenetic model of survivin-dependent molecular signalling pathways in tumorigenesis of oral cancer and precursor lesions.

Background: p53 tumour suppressor gene limits unchecked cellular growth in response to DNA damage, by causing G1 arrest and the activation of apoptosis. Inhibitors of apoptosis include survivin which acts by inhibition of caspases. Survivin has a significant role as a cell cycle modulator and is only minimally present in mature tissues. Aberrant expression of p53 and survivin has been evaluated in various carcinomas. Thus, the objective of this research was to elucidate the co-expression of p53 and survivin in tissue samples of Oral Potentially Malignant Disorders (OPMDs) and Oral Squamous Cell Carcinoma (OSCCs). Method: Thirty tissue samples of OPMDs and 30 tissue samples of OSCCs taken from department archives were used in the study. Expression of p53 and survivin was analyzed in the study groups by the help of immunohistochemistry. Also, co-expression of both the markers was evaluated. Results: The expression of p53 and survivin in the oral epithelium of patients with OSCCs was significantly higher than that in patients with OPMDs (P value ≤0.05). Conclusion: Our results provide insights into the altered survivin and p53 co-expression with significant immunoexpression within the study groups. Therefore, survivin and p53 could be better markers for identifying cell proliferation and apoptotic pathway. Also, malignant transformation rate of OPMD increases with increased expression of these markers.

Latifolin, a Natural Flavonoid, Isolated from the Heartwood of Dalbergia odorifera Induces Bioactivities through Apoptosis, Autophagy, and Necroptosis in Human Oral Squamous Cell Carcinoma.

Oral squamous cell carcinoma (OSCC) is the most common malignant neoplasm with frequent metastasis and high mortality in the oral cavity. Plant-derived natural compounds are actively progressing as a trend for cancer treatment. Latifolin (Latif), is a natural flavonoid isolated from the heartwood of Dalbergia odorifera T. Chen (D. odorifera) has been known to have beneficial effects on anti-aging, anti-carcinogenic, anti-inflammatory, and cardio-protective activities. However, the anti-cancer effects of Latif are unknown in OSCC. Herein, as a result of analysis in terms of the aggressive features of OSCCs, we found that Latif significantly inhibited the cell proliferation of human YD-8 and YD-10B OSCCs, and caused the anti-metastatic activities by effectively blocking cell migration, invasion, and adhesion via the inactivation of focal adhesion kinase (FAK)/non-receptor tyrosine kinase (Src). Moreover, we found that Latif induced apoptotic cell death to suppress the cell survival and proliferation of YD-10B OSCCs by targeting PI3K/AKT/mTOR/p70S6K signaling. Finally, we analyzed in terms of autophagy and necroptosis, which are other mechanisms of programmed cell death and survival compared to apoptosis in YD-10B OSCCs. We found that Latif suppressed autophagic-related proteins and autophagosome formation, and also Latif inhibited necroptosis by dephosphorylating necroptosis-regulatory proteins (RIP1, RIP3, and MLKL). Given these findings, our results provided new evidence for Latif's biological effect and mechanism in YD-10B OSCCs, suggesting that Latif may be a new candidate for patients with OSCCs.

Falcarindiol Stimulates Apoptotic and Autophagic Cell Death to Attenuate Cell Proliferation, Cell Division, and Metastasis through the PI3K/AKT/mTOR/p70S6K Pathway in Human Oral Squamous Cell Carcinomas.

Human oral squamous cell carcinomas (OSCCs) have high cancer mortality and a 5-year survival rate lower than that of most other carcinomas. New therapeutic strategies are required for the treatment and prevention against OSCCs. An approach to cancer therapy using plant-derived natural compounds has been actively in progress as a trend. Falcarindiol (FALC), or its isolated form Ostericum koreanum Kitagawa (O. koreanum), is present in many food and dietary plants, especially in carrots, and this compound has a variety of beneficial effects. However, biological activity of FALC has not been reported in OSCCs yet. This study aimed to demonstrate the antitumor effects of FALC against OSCCs, YD-10B cells. In this study, FALC was selected as a result of screening for compounds isolated from various natural products in YD-10B cells. FALC suppressed cell growth, and FALC-induced apoptotic cell death was mainly accompanied by the dephosphorylation of PI3K, AKT, mTOR, and p70S6K. The apoptotic cell death was also associated with autophagy as evidenced by the expression of Beclin-1, the conversion of LC3-II, and the formation of autophagosome. FALC-induced autophagy was accompanied by MAPKs including ERK1/2 and p38. Furthermore, FALC caused the antimetastatic effects by inhibiting the migration and invasion of YD-10B cells. Taken together, the findings suggest the potential value of FALC as a novel candidate for therapeutic strategy against OSCCs.

Exosomes-carrying Epstein-Barr virus-encoded small RNA-1 induces indoleamine 2, 3-dioxygenase expression in tumor-infiltrating macrophages of oral squamous-cell carcinomas and suppresses T-cell activity by activating RIG-I/IL-6/TNF-α pathway.

OBJECTIVES: Although exosomes carrying Epstein-Barr virus-encoded small RNA-1 (EBER-1) are involved in the immunosuppressive tumor microenvironments of EBV-associated head and neck carcinomas, the effects of EBER-1-associated exosomes on tumor-infiltrating macrophages are poorly understood. MATERIALS AND METHODS: The association between EBV infection and expression of indoleamine 2,3-dioxygenase (IDO) was assessed in 165 paraffin-embedded oral squamous cell carcinoma (OSCC) tissue samples. Using in vitro techniques, we investigated whether stimulation of the RIG-I/IL-6/TNF-α pathway by exosomes carrying EBER-1 is critical for IDO induction in macrophages. We performed a thymidine incorporation and a cell cytolytic assay to test for up-regulated IDO in macrophages that can block the proliferation and function of effector T cells. RESULTS: Some infiltrated macrophages expressed levels of IDO higher than OSCC cells which was significantly associated with presence of EBV. The production of IDO, tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) in human monocyte-derived macrophages (MDMs) was induced by EBV-associated exosomes in vitro. Mechanistically, the retinoic acid-inducible gene I (RIG-I) pathway in MDMs was stimulated by EBV-encoded small RNA-1 (EBER-1) whereas the inhibition of these pathways by BX-795 almost abolished the production of these two cytokines and IDO induction. Also, the EBER-1-activated IDO in MDMs suppressed the proliferation of T lymphocytes and diminished the cytolytic activity of CD8+ T cells. CONCLUSION: Exosomes carrying EBER-1 could induce IDO expression in MDMs, considerably aided by an IL-6 and TNF-α-dependent mechanism via the RIG-I signaling pathway, which might create an immunosuppressive microenvironment affecting T-cell immune responses.

CD147 promotes glucose metabolism, invasion and metastasis via PI3K/AKT pathway in oral squamous cell carcinomas.

BACKGROUND: The incidence of oral cancers, especially that of oral squamous cell carcinoma (OSCC), has increased significantly in the last few decades. Aggressive tumor progression and metastasis are the key factors responsible for the high mortality rate associated with OSCC. CD147 is known to play a key role in tumor metastasis and is associated with poor prognosis in oral cancer. It is also a crucial regulator of glucose metabolism in cancer cells. The aim of this study was to determine the effect of CD147 on OSCC invasiveness, metastasis and glucose metabolism, as well as the underlying mechanism. METHODS: CD147 was knocked down in the human OSCC lines SCC-25 and CAL-27, and both the wild-type and knockdown cells were then stably transfected with PI3K cDNA. Glucose metabolism and in vitro migration of the OSCC cells were respectively analyzed by glucose uptake and lactate secretion assays, and transwell assay. RESULTS: Knocking down CD147 in the OSCC cells significantly reduced their migration, and decreased glucose metabolism. The inhibitory effects of blocking CD147 were reversed upon PI3K overexpression. CONCLUSIONS: CD147 mediates its oncogenic effects via the PI3K/AKT pathway, and is a potential prognostic factor and therapeutic target for OSCC.

Role of Chemiluminescence examination as non-invasive diagnostic tool in early detection of Leukoplakia.

OBJECTIVES: To assess the efficacy of Chemiluminescent light (Vizilite plus) in enhancing visualization and its ability to highlight Leukoplakia lesion. MATERIAL AND METHODS: This was a cross-sectional study done on 40 study subjects. Subjects were inducted into the study irrespective of age and sex based on the specific inclusion and exclusion criteria. The lesion parameters like the location of the lesion, the shape of lesion, the size, the extent, borders and the presence or absence of any adjacent satellite lesions were assessed under Incandescent light followed by Toluidine blue and Vizilite plus examinations. Histopathological examination results were considered as the gold standard and TBLU and CHEM outcomes were compared to them. RESULTS: Vizilite plus examination method was most effective in assessing the size, borders and shape of the lesions followed by Toluidine blue and Incandescent light examinations. Toluidine blue and Vizilite plus examination methods demonstrated the sensitivity of 100% and specificity of 97.3%. They also demonstrated PPV of 100% and NPV of 75% with reliable accuracy of 97.5%. CONCLUSION: Chemiluminescent light is a stepping stone and has the potential to revolutionize the diagnostic protocol for patients with potentially premalignant lesions. The device can be used as a general oral mucosal examination system and may in particular improve the visualization of potentially premalignant lesions.

Super-charged NK cells inhibit growth and progression of stem-like/poorly differentiated oral tumors in vivo in humanized BLT mice; effect on tumor differentiation and response to chemotherapeutic drugs.

Therapeutic role of NK cells in solid tumors was challenged previously even though their role in hematological malignancies has clearly been established. Furthermore, functions and numbers of NK cells are greatly suppressed in oral cancer patients necessitating effective future NK immunotherapeutic strategies to aid in the control of disease. The humanized-BLT (hu-BLT) mice were used to implant stem-like/undifferentiated oral tumors to study the role of super-charged NK cells with and without feeding with AJ2 probiotic bacteria. Implanted CSC/undifferentiated tumors resected from NK-injected mice exhibited differentiated phenotype, grew slowly, and did not cause weight loss, whereas those from tumor-bearing mice without NK-injection remained relatively more stem-like/poorly-differentiated, grew faster, and caused significant weight loss. Moreover, in vitro NK-differentiated tumors were sensitive to chemotherapeutic drugs, and when implanted in the oral-cavity grew no or very small tumors in mice. When NK-mediated differentiation of tumors was blocked by IFN-γ and TNF-α antibodies before implantation, tumors grew rapidly, remained stem-like/poorly-differentiated and became resistant to chemotherapeutic drugs. Loss of NK cytotoxicity and decreased IFN-γ secretion in tumor-bearing mice in PBMCs, splenocytes, bone marrow derived immune cells and enriched NK cells was restored by the injection of super-charged NK cells with or without feeding with AJ2. Much greater infiltration of CD45+ and T cells were observed in tumors resected from the mice, along with the restored secretion of IFN-γ from purified T cells from splenocytes in NK-injected tumor-bearing mice fed with AJ2 probiotic bacteria. Thus, super-charged NK cells prevent tumor growth by restoring effector function resulting in differentiation of CSCs/undifferentiated-tumors in hu-BLT mice.

Induction of Split Anergy Conditions Natural Killer Cells to Promote Differentiation of Stem Cells through Cell-Cell Contact and Secreted Factors.

In this paper, we provide evidence that anergized NK cells through secreted factors and direct cell-cell contact have the ability to induce differentiation of healthy dental pulp stem cells and stem cell of apical papillae as well as transformed oral squamous cancer stem cell (OSCSC) and Mia-Paca-2, poorly differentiated stem-like pancreatic tumors, resulting in their resistance to NK cell-mediated cytotoxicity. Induction of NK cell resistance and differentiation in the stem cells correlated with the increased expression of CD54, B7H1, and MHC class I, and mediated by the combination of membrane-bound or secreted IFN-γ and TNF-α from the NK cells since antibodies to both cytokines and not each one alone were able to inhibit differentiation or resistance to NK cells. Similarly, antibodies to both TNF-α and IFN-γ were required to prevent NK-mediated inhibition of cell growth, and restored the numbers of the stem cells to the levels obtained when stem cells were cultured in the absence of anergized NK cells. Interestingly, the effect of anti-IFN-γ antibody in the absence of anti-TNF-α antibody was more dominant for the prevention of increase in surface receptor expression since its addition abrogated the increase in CD54, B7H1, and MHC class I surface expression. Antibodies to CD54 or LFA-1 was unable to inhibit differentiation whereas antibodies to MHC class I but not B7H1 increased cytotoxicity of well-differentiated oral squamous carcinoma cells as well as OSCSCs differentiated by the IL-2 + anti-CD16 mAb-treated NK cells whereas it inhibited the cytotoxicity of NK cells against OSCSCs. Thus, NK cells may inhibit the progression of cancer by killing and/or differentiation of cancer stem cells, which severely halt cancer growth, invasion, and metastasis.