NF-kappaB and Hsp70 are involved in the phospholipase Cgamma1 signaling pathway in colorectal cancer cells

Co-Stimulation of AGEs and LPS Induces Inflammatory Mediators through PLCγ1/JNK/NF-κB Pathway in MC3T3-E1 Cells

Advanced glycation end-products (AGEs) are increased under hyperglycemia in vivo and are associated with the onset of diabetes. According to previous studies, AGEs exacerbate inflammatory diseases. However, the mechanism by which AGEs aggravate osteoblast inflammation remains unknown. Therefore, the aim of this study was to determine the effects of AGEs on the production of inflammatory mediators in MC3T3-E1 cells and the underlying molecular mechanisms. Co-stimulation with AGEs and lipopolysaccharide (LPS) was found to increase the mRNA and protein levels of cyclooxygenase 2 (COX2), interleukin-1α (IL-1α), S100 calcium-binding protein A9 (S100A9), and the production of prostaglandin E2 (PGE2) compared to no stimulation (untreated control) or individual stimulation with LPS or AGEs. In contrast, the phospholipase C (PLC) inhibitor, U73122, inhibited these stimulatory effects. Co-stimulation with AGEs and LPS also increased the nuclear translocation of nuclear factor-kappa B (NF-κB) compared to no stimulation (untreated control) or individual stimulation with LPS or AGE. However, this increase was inhibited by U73122. Co-stimulation with AGEs and LPS-induced phosphorylated phospholipase Cγ1 (p-PLCγ1) and phosphorylated c-Jun N-terminal kinase (p-JNK) expression compared to no stimulation or individual stimulation with LPS or AGEs. U73122 inhibited the effects induced by co-stimulation. siPLCγ1 did not increase the expression of p-JNK and the translocation of NF-κB. Overall, co-stimulation with AGEs and LPS may promote inflammation mediators in MC3T3-E1 cells by activating the nuclear translocation of NF-κB via PLCγ1-JNK activation.

Role of PLCγ1 in the modulation of cell migration and cell invasion in glioblastoma

Phosphoinositide-specific phospholipases C (PLCs) are a class of enzymes involved in several cell activities, such as cell cycle regulation, proliferation, differentiation and cytoskeletal dynamics. Among these enzymes, PLCγ1 is one of the most expressed PLCs in the brain, contributing to a complex network in the developing nervous system. Several studies have shown that PLCγ1 signaling imbalance is linked to several brain disorders, including glioblastoma, the most aggressive brain tumor in adults. Indeed, it has been demonstrated a link between PLCγ1 inhibition and the arrest of glioma cell motility of fetal rat brain aggregates and the impairment of cell invasion abilities following its down-regulation. This study aims to determine the pathological influence of PLCγ1 in glioblastoma, through a translational study which combines in silico data, data from glioblastoma patients' samples and data on engineered cell lines. We found out that PLCγ1 gene expression correlates with the pathological grade of gliomas, and it is higher in fifty patients' glioblastoma tissue samples compared to twenty healthy controls. Moreover, it was demonstrated that PLCγ1 silencing in U87-MG leads to a reduction in cell migration and invasion abilities. The opposite trend was observed following PLCγ1 overexpression, suggesting an interesting possible involvement of PLCγ1 in gliomas' aggressiveness.

Recent advances in understanding the molecular role of phosphoinositide-specific phospholipase C gamma 1 as an emerging onco-driver and novel therapeutic target in human carcinogenesis

Phosphoinositide metabolism is crucial intracellular signaling system that regulates a plethora of biological functions including mitogenesis, cell proliferation and division. Phospholipase C gamma 1 (PLCγ1) which belongs to phosphoinositide-specific phospholipase C (PLC) family, is activated by many extracellular stimuli including hormones, neurotransmitters, growth factors and modulates several cellular and physiological functions necessary for tumorigenesis such as cell survival, migration, invasion and angiogenesis by generating inositol 1,4,5-triphosphate (IP3) and diacylglycerol (DAG) via hydrolysis of phosphatidylinositol 4,5-biphosphate (PIP2). Cancer remains as a leading cause of global mortality and aberrant expression and regulation of PLCγ1 is linked to a plethora of deadly human cancers including carcinomas of the breast, lung, pancreas, stomach, prostate and ovary. Although PLCγ1 cross-talks with many onco-drivers and signaling circuits including PI3K, AKT, HIF1-α and RAF/MEK/ERK cascade, its precise role in carcinogenesis is not completely understood. This review comprehensively discussed the status quo of this ubiquitously expressed phospholipase as a tumor driver and highlighted its significance as a novel therapeutic target in cancer. Furthermore, we have highlighted the significance of somatic driver mutations in PLCG1 gene and molecular roles of PLCγ1 in several major human cancers, a knowledgebase that can be utilized to develop novel, isoform-specific small molecule inhibitors of PLCγ1.

PLCγ1: Potential arbitrator of cancer progression

Phospholipase C (PLC) is an essential mediator of cellular signaling. PLC regulates multiple cellular processes by generating bioactive molecules such as inositol-1,4,5-triphosphate (IP₃) and diacylglycerol (DAG). These products propagate and regulate cellular signaling via calcium (Ca²⁺) mobilization and activation of protein kinase C (PKC), other kinases, and ion channels. PLCγ1, one of the primary subtypes of PLC, is directly activated by membrane receptors, including receptor tyrosine kinases (RTKs), and adhesion receptors such as integrin. PLCγ1 mediates signaling through direct interactions with other signaling molecules via SH domains, as well as its lipase activity. PLCγ1 is frequently enriched and mutated in various cancers, and is involved in the processes of tumorigenesis, including proliferation, migration, and invasion. Although many studies have suggested that PLCγ functions in cell mobility rather than proliferation in cancer, questions remain as to whether PLCγ regulates mitogenesis and whether PLCγ promotes or inhibits proliferation. Moreover, how PLCγ regulates cancer-associated cellular processes and the interplay among other proteins involved in cancer progression have yet to be fully elucidated. In this review, we discuss the current understanding of the role of PLCγ1 in cancer mobility and proliferation.

Sesamin manifests chemopreventive effects through the suppression of NF-kappa B-regulated cell survival, proliferation, invasion, and angiogenic gene products

Agents that are safe, affordable, and efficacious are urgently needed for the prevention of chronic diseases such as cancer. Sesamin, a lipid-soluble lignan, is one such agent that belongs to a class of phytoestrogens, isolated from sesame (Sesamum indicum), and has been linked with prevention of hyperlipidemia, hypertension, and carcinogenesis through an unknown mechanism. Because the transcription factor NF-kappaB has been associated with inflammation, carcinogenesis, tumor cell survival, proliferation, invasion, and angiogenesis of cancer, we postulated that sesamin might mediate its effect through the modulation of the NF-kappaB pathway. We found that sesamin inhibited the proliferation of a wide variety of tumor cells including leukemia, multiple myeloma, and cancers of the colon, prostate, breast, pancreas, and lung. Sesamin also potentiated tumor necrosis factor-alpha-induced apoptosis and this correlated with the suppression of gene products linked to cell survival (e.g., Bcl-2 and survivin), proliferation (e.g., cyclin D1), inflammation (e.g., cyclooxygenase-2), invasion (e.g., matrix metalloproteinase-9, intercellular adhesion molecule 1), and angiogenesis (e.g., vascular endothelial growth factor). Sesamin downregulated constitutive and inducible NF-kappaB activation induced by various inflammatory stimuli and carcinogens, and inhibited the degradation of IkappaBalpha, the inhibitor of NF-kappaB, through the suppression of phosphorylation of IkappaBalpha and inhibition of activation of IkappaBalpha protein kinase, thus resulting in the suppression of p65 phosphorylation and nuclear translocation, and NF-kappaB-mediated reporter gene transcription. The inhibition of IkappaBalpha protein kinase activation was found to be mediated through the inhibition of TAK1 kinase. Overall, our results showed that sesamin may have potential against cancer and other chronic diseases through the suppression of a pathway linked to the NF-kappaB signaling.

Molecular mechanisms of psychostimulant-induced structural plasticity

Drug addiction is characterized by persistent behavioral and cellular plasticity throughout the brain's reward regions. Among the many neuroadaptations that occur following repeated drug administration are alterations in cell morphology including changes in dendritic spines. While this phenomenon has been well documented, the underlying molecular mechanisms are poorly understood. Here, within the context of drug abuse, we review and integrate several of the established pathways known to regulate synaptic remodeling, and discuss the contributions of neurotrophic and dopamine signaling in mediating this structural plasticity. Finally, we discuss how such upstream mechanisms could regulate actin dynamics, the common endpoint involved in structural remodeling in neurons.

Cardenolide-induced lysosomal membrane permeabilization demonstrates therapeutic benefits in experimental human non-small cell lung cancers

Non-small cell lung cancers (NSCLCs) are the leading cause of cancer deaths in most developed countries. Targeting heat shock protein 70 (Hsp70) expression and function, together with the induction of lysosomal membrane permeabilization (LMP), could overcome the multiple anti-cell death mechanisms evidenced in NSCLCs that are responsible for the failure of currently used chemotherapeutic drugs. Because cardenolides bind to the sodium pump, they affect multiple signaling pathways and thus have a number of marked effects on tumor cell behavior. The aim of the present study was to characterize in vitro and in vivo the antitumor effects of a new cardenolide (UNBS1450) on experimental human NSCLCs. UNBS1450 is a potent source of in vivo antitumor activity in the case of paclitaxel-and oxaliplatin-resistant subcutaneous human NCI-H727 and orthotopic A549 xenografts in nude mice. In vitro UNBS1450-mediated antitumor activity results from the induction of nonapoptotic cell death. UNBS1450 mediates the decrease of Hsp70 at both mRNA and protein levels, and this is at least partly due to UNBS1450-induced downregulation of NFAT5/TonEBP (a factor responsible for the transcriptional control of Hsp70). These effects were paralleled by the induction of LMP, as evidenced by acridine orange staining and immunofluorescence analysis for cathepsin B accumulation.