The discovery of interleukin-2 (IL-2) changed the molecular understanding of how the immune system is controlled. IL-2 is a pleiotropic cytokine, and dissecting the signaling pathways that allow IL-2 ...to control the differentiation and homeostasis of both pro- and anti-inflammatory T cells is fundamental to determining the molecular details of immune regulation. The IL-2 receptor couples to JAK tyrosine kinases and activates the STAT5 transcription factors. However, IL-2 does much more than control transcriptional programs; it is a key regulator of T cell metabolic programs. The development of global phosphoproteomic approaches has expanded the understanding of IL-2 signaling further, revealing the diversity of phosphoproteins that may be influenced by IL-2 in T cells. However, it is increasingly clear that within each T cell subset, IL-2 will signal within a framework of other signal transduction networks that together will shape the transcriptional and metabolic programs that determine T cell fate.
Cholesterol/sphingolipid-rich membrane domains, known as lipid rafts or membrane rafts, play a critical role in the compartmentalization of signaling pathways. Physical segregation of proteins in ...lipid rafts may modulate the accessibility of proteins to regulatory or effector molecules. Thus, lipid rafts serve as sorting platforms and hubs for signal transduction proteins. Cancer cells contain higher levels of intracellular cholesterol and lipid rafts than their normal non-tumorigenic counterparts. Many signal transduction processes involved in cancer development (insulin-like growth factor system and phosphatidylinositol 3-kinase-AKT) and metastasis cluster of differentiation (CD)44 are dependent on or modulated by lipid rafts. Additional proteins playing an important role in several malignant cancers (e.g., transmembrane glycoprotein mucin 1) are also being detected in association with lipid rafts, suggesting a major role of lipid rafts in tumor progression. Conversely, lipid rafts also serve as scaffolds for the recruitment and clustering of Fas/CD95 death receptors and downstream signaling molecules leading to cell death-promoting raft platforms. The partition of death receptors and downstream signaling molecules in aggregated lipid rafts has led to the formation of the so-called cluster of apoptotic signaling molecule-enriched rafts, or CASMER, which leads to apoptosis amplification and can be pharmacologically modulated. These death-promoting rafts can be viewed as a linchpin from which apoptotic signals are launched. In this review, we discuss the involvement of lipid rafts in major signaling processes in cancer cells, including cell survival, cell death, and metastasis, and we consider the potential of lipid raft modulation as a promising target in cancer therapy.
Chronic myeloid leukemia (CML), a myeloproliferative hematopoietic cancer, is caused by a genetic translocation between chromosomes 9 and 22. This translocation produces a small Philadelphia ...chromosome, which contains the
Bcr-Abl
oncogene. The
Bcr-Abl
oncogene encodes the BCR-ABL protein, upregulates various signaling pathways (JAK-STAT, MAPK/ERK, and PI3K/Akt/mTOR), and out of which the specifically highly active pathway is the PI3K/Akt/mTOR pathway. Among early treatments for CML, tyrosine kinase inhibitors (TKIs) were found to be the most effective, but drug resistance against kinase inhibitors led to the discovery of novel alternative therapies. At this point, the PI3K/Akt/mTOR pathway components became new targets due to stimulation of this pathway in TKIs-resistant CML patients. The current review article deals with reviewing the scientific literature on the PI3K/Akt/mTOR pathway inhibitors listed in the National Cancer Institute (NCI) drug dictionary and proved effective against multiple cancers. And out of those enlisted inhibitors, the US FDA has also approved some PI3K inhibitors (Idelalisib, Copanlisib, and Duvelisib) and mTOR inhibitors (Everolimus, Sirolimus, and Temsirolimus) for cancer therapy. So far, several inhibitors have been tested, and further investigations are still ongoing. Even in Imatinib, Nilotinib, and Ponatinib-resistant CML cells, a dual PI3K/mTOR inhibitor, BEZ235, showed antiproliferative activity. Therefore, by considering the literature data of these reviews and further examining some of the reported inhibitors, which proved effective against the PI3K/Akt/mTOR signaling pathway in multiple cancers, may improve the therapeutic approaches towards TKI-resistant CML cells where the respective signaling pathway gets upregulated.
Phosphatidylinositol 3-kinases (PI3Ks) are important therapeutic targets for the treatment of cancer, thrombosis, and inflammatory and immune diseases. The four highly homologous Class I isoforms, ...PI3K, PI3K, PI3K and PI3K have unique, non-redundant physiological roles and as such, isoform selectivity has been a key consideration driving inhibitor design and development. In this review, we discuss the structural biology of PI3Ks and how our growing knowledge of structure has influenced the medicinal chemistry of PI3K inhibitors. We present an analysis of the available structure-selectivity-activity relationship data to highlight key insights into how the various regions of the PI3K binding site influence isoform selectivity. The picture that emerges is one that is far from simple and emphasizes the complex nature of protein-inhibitor binding, involving protein flexibility, energetics, water networks and interactions with non-conserved residues.
Nephrotoxicity is one of the most serious health consequences of cadmium (Cd) toxic exposure. Cd was associated with nephrotoxicity through different mechanisms including apoptosis, inflammation, and ...oxidative stress. This study investigated the effects of glimepiride on renal inflammatory reactions and oxidative stress in response to Cd in mice animal model, pointing to the possible role of JNK/NF-кB and PI3K/AKT signaling.
Four groups of animals were created; the control group, the glimepiride group (4 mg/kg; i.p.), CdCl2 nephrotoxic group (6.5 mg/kg; i.p.), and the CdCl2/glimepiride group. On the other hand, molecular docking studies were used to investigate the affinity of glimepiride towards JNK, AKT, and PI3K targets.
The CdCl2 group's serum creatinine and urea levels were found to have a significant increase when compared to the normal group. High expression of 8-OHDG, JNK, AKT, and NGAL was also detected in the CdCl2 group. In addition, coagulative necrosis of the renal tubules and increased immunostaining of NF-κB and PI3K. Furthermore, glimepiride significantly decreased the serum creatinine and urea level and alleviated the degenerative and necrotic changes within the renal tubules. Moreover, the renal NGAL and JNK were suppressed, and oxidants/antioxidants hemostasis was observed.
The available data show that glimepiride is an attractive strategy for improving the nephrotoxicity associated with CdCl2 through inhibition of JNK/NF-κB, PI3K/AKT inflammatory pathways. From the abovementioned results, glimepiride treatment might be a potential therapeutic approach to treat renal tissue against severe acute renal damage induced by the toxic effects of CdCl2.
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Despite development of novel agents targeting oncogenic pathways, matching targeted therapies to the genetic status of individual tumors is proving to be a daunting task for clinicians. To improve ...the clinical efficacy and to reduce the toxic side effects of treatments, a deep characterization of genetic alterations in different tumors is required. The mutational profile often evidences a gain of function or hyperactivity of phosphoinositide 3-kinases (PI3Ks) in tumors. These enzymes are activated downstream tyrosine kinase receptors (RTKs) and/or G proteins coupled receptors (GPCRs) and, via AKT, are able to induce mammalian target of rapamycin (mTOR) stimulation. Here, we elucidate the impact of class I (p110α, β, γ, and δ) catalytic subunit mutations on AKT-mediated cellular processes that control crucial mechanisms in tumor development. Moreover, the interrelation of PI3K signaling with mTOR, ERK, and RAS pathways will be discussed, exploiting the potential benefits of PI3K signaling inhibitors in clinical use.
Lectin galactoside-binding soluble 3-binding protein (LGALS3BP) is associated with cancer metastasis and is a promising prognostic marker in neoplasms. In hepatocellular carcinoma (HCC), the ...prognostic impact and pro-metastatic function of LGALS3BP remain unclear. This study evaluated the endogenous LGALS3BP expression in HCC tissue and its association with prognosis. LGALS3BP protein levels were significantly elevated in clinical HCC tissues and cell lines. Increased LGALS3BP expression was closely associated with disease progression in HCC patients, and they also exhibited an unfavorable prognosis. Furthermore, the knockdown of LGALS3BP inhibited the growth, migration, and invasion of HCC cells in vitro. In mice xenografts, silencing LGALS3BP significantly inhibited tumor cell growth in vivo. Mechanically, upon LGALS3BP depletion, the tumor-suppressive function was dependent on inactivating Phosphatidylinositol 3-kinase (PI3K)/V-akt murine thymoma viral oncogene homolog (AKT) signaling pathway. Collectively, these findings suggest that LGALS3BP employs a pro-tumorigenic function in HCC and may be a promising HCC prognostic marker.
•LGALS3BP is dramatically elevated in clinical hepatocellular carcinoma (HCC) tissues as well as cell lines.•Higher LGALS3BP expression causes to an unfavorable prognosis.•Knockdown of LGALS3BP suppresses HCC cell growth in vitro and in vitro.•LGALS3BP exerts a pro-tumorigenic function in HCC via regulating PI3K/AKT signaling.
Common capillary malformations are red vascular skin lesions, most commonly associated with somatic activating GNAQ or GNA11 mutations. We focused on capillary malformations lacking such a mutation ...to identify previously unreported genetic causes. We used targeted next-generation sequencing on 82 lesions. Bioinformatic analysis allowed the identification of 9 somatic pathogenic variants in PIK3R1 and PIK3CA, encoding for the regulatory and catalytic subunits of phosphoinositide 3-kinase, respectively. Recharacterization of these lesions unraveled a common phenotype: a pale capillary malformation associated with visible dilated veins. Primary endothelial cells from 2 PIK3R1-mutated lesions were isolated, and PI3k-Akt-mTOR and RAS–RAF–MAPK signaling were assessed by western blot. This unveiled an abnormal increase in Akt phosphorylation, effectively reduced by PI3K pathway inhibitors, such as mTOR, Akt, and PIK3CA inhibitors. The effects of mutant PIK3R1 were further studied using zebrafish embryos. Endothelium-specific expression of PIK3R1 mutants resulted in abnormal development of the posterior capillary–venous plexus. In summary, capillary malformation associated with visible dilated veins emerges as a clinical entity associated with somatic pathogenic variants in PIK3R1 or PIK3CA (nonhotspot). Our findings suggest that the activated Akt signaling can be effectively reversed by PI3K pathway inhibitors. In addition, the proposed zebrafish model holds promise as a valuable tool for future drug screening aimed at developing patient-tailored treatments.
Diabetes is a disorder of glucose metabolism, and over 90% are type 2 diabetes. Diabetic cardiomyopathy (DCM) is one of the type 2 diabetes complications, usually accompanied by changes in myocardial ...structure and function, together with cardiomyocyte apoptosis. Our study investigated the effect of curcumin on regulating oxidative stress (OS) and apoptosis in DCM. In vivo, diabetes was induced in an experimental rat model by streptozoticin (STZ) together with high‐glucose and high‐fat (HG/HF) diet feeding. In vitro, H9c2 cardiomyocytes were cultured with high‐glucose and saturated free fatty acid palmitate. Curcumin was orally or directly administered to rats or cells, respectively. Streptozoticin ‐induced diabetic rats showed metabolism abnormalities and elevated markers of OS (superoxide dismutase SOD, malondialdehyde MDA, gp91phox, Cyt‐Cyto C), enhanced cell apoptosis (Bax/Bcl‐2, Cleaved caspase‐3, TUNEL‐positive cells), together with reduced Akt phosphorylation and increased Foxo1 acetylation. Curcumin attenuated the myocardial dysfunction, OS and apoptosis in the heart of diabetic rats. Curcumin treatment also enhanced phosphorylation of Akt and inhibited acetylation of Foxo1. These results strongly suggest that apoptosis was increased in the heart of diabetic rats, and curcumin played a role in diabetic cardiomyopathy treatment by modulating the Sirt1‐Foxo1 and PI3K‐Akt pathways.
This study explores the effect of COL1A2, COL6A3, and THBS2 gene silencing on proliferation, migration, invasion, and apoptosis of gastric cancer cells through the PI3K‐Akt signaling pathway. The ...gastric cancer microarray expression data (GSE19826, GSE79973, and GSE65801) was analyzed. Gastric cancer tissues and corresponding adjacent normal tissues were extracted from patients. Positive expression rate of PI3K, Akt, and p‐Akt was measured with immunohistochemistry. Two cell lines, BGC‐823 and SGC‐7901, were transfected and cells were grouped into blank, negative control, COL1A2‐shRNA, COL6A3‐shRNA, and THBS2‐shRNA groups. Expressions of COL1A2, COL6A3, and THBS2 in gastric cancer cells transfected with corresponding silencing sequences were evaluated by RT‐qPCR and Western blot. MTT assay, Transwell, and cell scratch tests were conducted to evaluate cell proliferation, invasion, and migration capacity, respectively. Flow cytometry was used to evaluate cell cycle distribution and apoptosis. The positive expression of PI3K, Akt, and p‐Akt was higher in gastric cancer tissues compared with adjacent normal tissues, and the mRNA expression of COL1A2, COL6A3, and THBS2 was increased in gastric cancer tissues. Akt, p‐Akt, and PI3K expression drastically decreased in cells transfected with COL1A2, COL6A3, and THBS2 silencing sequences. Cells transfected with COL1A2, COL6A3, and THBS2 silencing sequences exhibited promoted apoptosis but inhibited proliferation, migration, and invasion. This study demonstrates that COL1A2, COL6A3, and THBS2 gene silencing inhibits gastric cancer cell proliferation, migration, and invasion while promoting apoptosis through the PI3K‐Akt signaling pathway.
COL1A2, COL6A3, and THBS2 gene silencing inhibits gastric cancer cell proliferation, migration, and invasion while promoting apoptosis through the PI3K‐Akt signaling pathway.
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