PAR-2 promotes cell proliferation, migration, and invasion through activating PI3K/AKT signaling pathway in oral squamous cell carcinoma

Linagliptin's impact on lymphatic barrier and lymphangiogenesis in oral cancer with high glucose

OBJECTIVES

Uncertainties remain regarding the effect of elevated glucose levels on lymphatic metastasis of cancer cells. Our study elucidated the mechanisms linking high glucose to lymphangiogenesis and lymphatic barrier-related factors and investigated the protective role of linagliptin against lymphatic barrier dysfunction.

MATERIALS AND METHODS

A CAL-27-LEC co-culture system was established. Sodium fluorescein permeability assay observed lymphatic endothelial cell permeability. Western blotting and RT-qPCR detected protein and mRNA expression under different conditions, respectively. CCK-8, scratch wound healing, and transwell assays revealed cell migration and proliferation. Tube formation experiment tested capacity for endothelial tube formation. Immunohistochemical staining analyzed tissue sections from 43 oral cancer individuals with/without diabetes.

RESULTS

In high-glucose co-culture system, we observed increased lymphatic barrier permeability and decreased expression of ZO-1 and occludin, two tight-junction proteins; conversely, the expression of PAR2, a high permeability-related protein, was increased. Following linagliptin treatment, the expression levels of VEGF-C, VEGFR-3, and PAR2 decreased, while those of ZO-1 and occludin increased. Considerably higher levels of LYVE-1 expression in individuals with diabetes than in those without diabetes.

CONCLUSIONS

By ameliorating the high glucose-induced disruption of the lymphatic endothelial barrier, linagliptin may reduce lymphangiogenesis and exhibit an inhibitory effect on lymphatic metastasis in oral cancer patients with diabetes.

Rivaroxaban attenuates neutrophil maturation in the bone marrow niche

Pharmacological inhibition of factor Xa by rivaroxaban has been shown to mediate cardioprotection and is frequently used in patients with, e.g., atrial fibrillation. Rivaroxaban's anti-inflammatory actions are well known, but the underlying mechanisms are still incompletely understood. To date, no study has focused on the effects of rivaroxaban on the bone marrow (BM), despite growing evidence that the BM and its activation are of major importance in the development/progression of cardiovascular disease. Thus, we examined the impact of rivaroxaban on BM composition under homeostatic conditions and in response to a major cardiovascular event. Rivaroxaban treatment of mice for 7 days markedly diminished mature leukocytes in the BM. While apoptosis of BM-derived mature myeloid leukocytes was unaffected, lineage-negative BM cells exhibited a differentiation arrest at the level of granulocyte-monocyte progenitors, specifically affecting neutrophil maturation via downregulation of the transcription factors Spi1 and Csfr1. To assess whether this persists also in situations of increased leukocyte demand, mice were subjected to cardiac ischemia/reperfusion injury (I/R): 7 d pretreatment with rivaroxaban led to reduced cardiac inflammation 72 h after I/R and lowered circulating leukocyte numbers. However, BM myelopoiesis showed a rescue of the leukocyte differentiation arrest, indicating that rivaroxaban's inhibitory effects are restricted to homeostatic conditions and are mainly abolished during emergency hematopoiesis. In translation, ST-elevation MI patients treated with rivaroxaban also exhibited reduced circulating leukocyte numbers. In conclusion, we demonstrate that rivaroxaban attenuates neutrophil maturation in the BM, which may offer a therapeutic option to limit overshooting of the immune response after I/R.

Role of PI3K/AKT pathway in squamous cell carcinoma with an especial focus on head and neck cancers

PI3K/AKT pathway is an important pathway in the carcinogenesis since it has central impacts in the regulation of metabolic pathways, cell proliferation and survival, gene expression and protein synthesis. This pathway has been reported to be dysregulated in several types of cancers. In the current review, we summarize the role of this signaling pathway in squamous cell carcinomas (SCCs) originated from different parts of body cervix, oral cavity, head and neck and skin. The data presented in the current review shows the impact of dysregulation of PI3K/AKT pathway in survival of patients with SCC. Moreover, targeted therapies against this pathway have been found to be effective in reduction of tumor burden both in animal models and clinical settings. Finally, a number of molecules that regulate PI3K/AKT pathway can be used as diagnostic markers for different types of SCCs.

miR-186-5p inhibits the progression of oral squamous cell carcinoma by targeting ITGA6 to impair the activity of the PI3K/AKT pathway

BACKGROUND

microRNAs (miRNAs) are pivotal regulators of multiple biological processes. miR-186-5p functions as a tumor suppressor in a variety of cancers and promotes the malignant proliferation of oral squamous cell carcinoma (OSCC). This study aimed to clarify the role and regulatory mechanism of miR-186-5p in OSCC.

METHODS

The levels of miR-186-5p and integrin subunit alpha 6 (ITGA6) were investigated in clinical specimens and OSCC cell lines by reverse transcription-quantitative polymerase chain reaction. The effects of miR-186-5p and ITGA6 on the cell migration, proliferation, and phosphatidylinositol 3-kinase (PI3K)/serine-threonine kinase (AKT) pathway activity were evaluated by transwell assay, cell counting kit 8 assay, and western blotting, respectively. A xenograft model was used to analyze the effect of miR-186-5p on tumor growth. Bioinformatic analyses were conducted to identify the putative targets of miR-186-5p in OSCC.

RESULTS

Decreased miR-186-5p expression levels were observed in OSCC tumor tissues and cell lines. The overexpression of miR-186-5p suppressed the proliferation and migration of OSCC cells, and weakened the phosphorylation of PI3K and AKT. Moreover, the overexpression of miR-186-5p in xenograft tumor models impedes tumor growth. miR-186-5p is bound to ITGA6 and negatively related to ITGA6 expression in tumor tissues. The forced expression of ITGA6 promoted OSCC cell proliferation and migration and enhanced the phosphorylation levels of PI3K and AKT, while additional miR-186-5p enrichment partly abolished these effects.

CONCLUSION

miR-186-5p binds to ITGA6 to impair the activity of the PI3K/AKT signaling pathway, thereby blocking the development of OSCC. This study provides insight to understand the pathogenesis of OSCC.

Therapeutic Perspectives for the Perioperative Period in Oral Squamous Cell Carcinoma (OSCC)

The perioperative period is the relatively short window of time, usually measured in days or weeks, around the surgical procedure. Despite its short duration, this time period is of great importance for cancer patients. From a biological point of view, the perioperative period is complex. Synchronous with primary tumor removal, surgery has local and distant consequences, including systemic and local inflammation, coagulation and sympathetic activation. Furthermore, the patients often present comorbidities and receive several medical prescriptions (hypnotics, pain killers, anti-emetics, hemostatics, inotropes, antibiotics). Because of the complex nature of the perioperative period, it is often difficult to predict the oncological outcome of tumor resection. Here, we review the biological consequences of surgery of Oral Squamous Cell Carcinoma (OSCC), the most frequent form of primary head and neck tumors. We briefly address the specificities and the challenges of the surgical care of these tumors and highlight the biological and clinical studies that offer insight into the perioperative period. The recent trials examining neoadjuvant immunotherapy for OSCC illustrate the therapeutic opportunities offered by the perioperative period.

Oral Versus Gastrointestinal Mucosal Immune Niches in Homeostasis and Allostasis

Different body systems (epidermis, respiratory tract, cornea, oral cavity, and gastrointestinal tract) are in continuous direct contact with innocuous and/or potentially harmful external agents, exhibiting dynamic and highly selective interaction throughout the epithelia, which function as both a physical and chemical protective barrier. Resident immune cells in the epithelia are constantly challenged and must distinguish among antigens that must be either tolerated or those to which a response must be mounted for. When such a decision begins to take place in lymphoid foci and/or mucosa-associated lymphoid tissues, the epithelia network of immune surveillance actively dominates both oral and gastrointestinal compartments, which are thought to operate in the same immune continuum. However, anatomical variations clearly differentiate immune processes in both the mouth and gastrointestinal tract that demonstrate a wide array of independent immune responses. From single vs. multiple epithelia cell layers, widespread cell-to-cell junction types, microbial-associated recognition receptors, dendritic cell function as well as related signaling, the objective of this review is to specifically contrast the current knowledge of oral versus gut immune niches in the context of epithelia/lymphoid foci/MALT local immunity and systemic output. Related differences in 1) anatomy 2) cell-to-cell communication 3) antigen capture/processing/presentation 4) signaling in regulatory vs. proinflammatory responses and 5) systemic output consequences and its relations to disease pathogenesis are discussed.

Deciphering the Role of the Coagulation Cascade and Autophagy in Cancer-Related Thrombosis and Metastasis

Thrombotic complications are the second leading cause of death among oncology patients worldwide. Enhanced thrombogenesis has multiple origins and may result from a deregulation of megakaryocyte platelet production in the bone marrow, the synthesis of coagulation factors in the liver, and coagulation factor signaling upon cancer and the tumor microenvironment (TME). While a hypercoagulable state has been attributed to factors such as thrombocytosis, enhanced platelet aggregation and Tissue Factor (TF) expression on cancer cells, further reports have suggested that coagulation factors can enhance metastasis through increased endothelial-cancer cell adhesion and enhanced endothelial cell activation. Autophagy is highly associated with cancer survival as a double-edged sword, as can both inhibit and promote cancer progression. In this review, we shall dissect the crosstalk between the coagulation cascade and autophagic pathway and its possible role in metastasis and cancer-associated thrombosis formation. The signaling of the coagulation cascade through the autophagic pathway within the hematopoietic stem cells, the endothelial cell and the cancer cell are discussed. Relevant to the coagulation cascade, we also examine the role of autophagy-related pathways in cancer treatment. In this review, we aim to bring to light possible new areas of cancer investigation and elucidate strategies for future therapeutic intervention.

Proteinase-activated receptor 2 promotes 3T3-L1 preadipocyte differentiation through activation of the PI3K/AKT signalling pathway and MAT2A gene expression

The present study aimed to investigate the function and mechanisms of PAR2 in preadipocyte differentiation. This study found that the expression level of PAR2 was increased during 3T3-L1 mouse preadipocyte differentiation towards adipocytes. In addition, PAR2 overexpression significantly stimulated the expression of adipogenic proteins including ACC1, PPARγ, and SREBF1. Moreover, PAR2 overexpression increased the content of triglyceride (TG) in 3T3-L1 preadipocytes. Knockdown of PAR2 suppressed 3T3-L1 preadipocyte differentiation and adipogenesis. Mechanistically, PAR2 promoted 3T3-L1 preadipocyte differentiation and TG production through activation of the PI3K/AKT signalling pathway and MAT2A gene expression. The research sheds light on the adipogenic effects of PAR2 and its underlying mechanisms. Thus, PAR2 may have therapeutic significance for obesity.

Downregulation of PER2 Promotes Tumor Progression by Enhancing Glycolysis via the Phosphatidylinositol 3-Kinase/Protein Kinase B Pathway in Oral Squamous Cell Carcinoma

PURPOSE

PER2 gene expression is downregulated in oral squamous cell carcinoma (OSCC) and may have a pivotal role in tumor suppression. However, the biological function and mechanism of action of PER2 in OSCC remain unclear. In this study, the biological functions and anticancer mechanisms of PER2 in OSCC were investigated.

MATERIALS AND METHODS

Both stably overexpressed and silenced PER2 OSCC cells were established as an experimental group; empty vector lentivirus and scramble short hairpin RNA lentivirus transfected-cells, as negative control groups; and untreated OSCC cells, as a blank group. Cell proliferation, apoptosis, and glycolysis potential assays were conducted. In addition, the expression of phosphatidylinositol 3-kinase (PI3K), protein kinase B (AKT), phosphorylation of protein kinase B, hexokinase 2 (HK2), pyruvate kinase M (PKM2), and lactate dehydrogenase A (LDHA) was quantified by real-time quantitative polymerase chain reaction and Western blotting. Rescue experiments were performed by the addition of AKT activators in the overexpressed cell line and by the addition of glycolysis inhibitor in the silenced cell line. These findings were verified in vivo using stably transfected OSCC cells overexpressing PER2 implanted in nude mice.

RESULTS

PER2 overexpression significantly inhibited OSCC cell proliferation and glycolysis, promoted cell apoptosis, and reduced the expression of PI3K, phosphorylation of protein kinase B, HK2, PKM2, and LDHA. The converse was observed in PER2-silenced OSCC cells. After the addition of AKT activator to cultures of PER2-overexpressed OSCC cells, reduced glucose uptake, lactic acid production, and cell proliferation, combined with increased apoptosis, were substantially reversed. In addition, after the addition of HK2 inhibitor to PER2-silenced OSCC cells to inhibit glycolysis, the reduction in apoptosis and increased proliferation were significantly countermanded. Tumorigenesis experiments in vivo also confirmed that PER2 overexpression suppressed OSCC growth and decreased the expression of HK2, PKM2, and LDHA.

CONCLUSIONS

PER2 heightened glycolysis via the PI3K/AKT pathway, heightened cell proliferation and inhibited apoptosis via glycolysis, thereby promoting the development of OSCC.