Role of mammalian target of rapamycin (mTOR) signalling in oncogenesis

The Role of mTOR in the Doxorubicin-Induced Cardiotoxicity: A Systematic Review

Doxorubicin (DOX) is a chemotherapy drug known to induce metabolic changes in the heart, leading to potential heart toxicity. These changes impact various cellular functions and pathways such as disrupting the mechanistic target of rapamycin (mTOR) signaling pathway. The study aimed to investigate the effect of DOX on the mTOR pathway through an in vivo systematic review. Databases were searched on September 11, 2023. We finally included 30 in vivo studies that examined the mTOR expression in cardiac tissue samples. The present study has shown that the PI3K/AKT/mTOR, the AMPK/mTOR, the p53/mTOR signaling, the mTOR/TFEB pathway, the p38 MAPK/mTOR, the sestrins/mTOR, and the KLF15/eNOS/mTORC1 signaling pathways play a crucial role in the development of DOX-induced cardiotoxicity. Inhibition or dysregulation of these pathways can lead to increased oxidative stress, apoptosis, and other adverse effects on the heart. Strategies that target and modulate the mTOR pathways, such as the use of mTOR inhibitors like rapamycin, have the potential to enhance the anticancer effects of DOX while also mitigating its cardiotoxic side effects.

Pharmacological modulation of PI3K/PTEN/Akt/mTOR/ERK signaling pathways in ischemic injury: a mechanistic perspective

Ischemia, also known as ischemia, relates to the reduced blood movement to a cells, muscle group, or organ in the body, culminating in an insufficient amount of oxygen required for cellular metabolism and the maintenance of tissue viability. There are different types of stroke (ischemic stroke, intracerebral hemorrhage, subarachnoid hemorrhage), and different causes of stroke (e.g., cardioembolic, atherothrombotic, lacunar ischemic strokes, aneurysmal subarachnoid hemorrhage). It also includes other disorders affecting the blood vessels in the brain (e.g., vascular malformations, unruptured aneurysms). Each of these conditions has different characteristics in terms of how common they are and how they are managed. Stroke is the primary and catastrophic clinical presentation of all cerebrovascular diseases. In this review we focused about the importance of PI3K/AKT signaling pathways which are important in the onset of ischemia-reperfusion (I/R) injury. In addition, mTOR, a target that is activated by the PI3K/Akt signaling pathway, is both required and capable of providing enough protection to the heart against harm caused by I/R. Moreover, the signaling pathways that involve PI3K/Akt/Erk/PTEN/mTOR play a crucial role in facilitating the proliferation and maintenance of neurons following an ischemic stroke. The current review summarizes the molecular mechanisms of various signaling pathways in ischemic diseases and suggests targeting its receptors as a preventive approach based on pre-clinical and clinical studies.

Distinct mRNA expression profiles and miRNA regulators of the PI3K/AKT/mTOR pathway in breast cancer: insights into tumor progression and therapeutic targets

Background

Breast cancer remains a leading cause of mortality among women, driven by the molecular complexity of its various subtypes. This study aimed to investigate the differential expression of genes and miRNAs involved in the PI3K/AKT/mTOR signaling pathway, a critical regulator of cancer progression.

Methods

We analyzed tumor tissues from five breast cancer subtypes-luminal A, luminal B HER2-negative, luminal B HER2-positive, HER2-positive, and triple-negative breast cancer (TNBC)-and compared them with non-cancerous tissues. Microarray and qRT-PCR techniques were employed to profile mRNAs and miRNAs, while bioinformatic tools predicted miRNA-mRNA interactions. Statistical analysis was performed with a statistical significance threshold (p) < 0.05.

Results

We identified several upregulated genes across all subtypes, with TNBC and HER2-positive cancers showing the most significant changes. Key genes such as COL1A1, COL4A1, PIK3CA, PIK3R1, and mTOR were found to be overexpressed, correlating with increased cancer aggressiveness. miRNA analysis revealed that miR-190a-3p, miR-4729, and miR-19a-3p potentially regulate these genes, influencing the PI3K/AKT/mTOR pathway. For instance, reduced expression of miR-190a-3p may contribute to the overexpression of PIK3CA and other pathway components, enhancing metastatic potential.

Conclusion

Our findings suggest that the PI3K/AKT/mTOR pathway and its miRNA regulators play crucial roles in breast cancer progression, particularly in aggressive subtypes like TNBC. The identified miRNAs and mRNAs hold potential as biomarkers for diagnosis and treatment, but further validation in functional studies is required. This study provides a foundation for targeted therapies aimed at modulating this critical pathway to improve breast cancer outcomes.

Microarray Analysis of Visceral Adipose Tissue in Obese Women Reveals Common Crossroads Among Inflammation, Metabolism, Addictive Behaviors, and Cancer: AKT3 and MAPK1 Cross Point in Obesity

Background: Visceral adipose tissue (VAT) abnormalities are directly associated with obesity-associated disorders. The underlying mechanisms that confer increased pathological risk to VAT in obesity have not been fully described. Methods: A case-control study was conducted that included 10 women with obesity (36.80 ± 7.39 years, BMI ≥ 30 kg/m2) and 10 women of normal weight (32.70 ± 9.45 years, BMI < 24.9 kg/m2). RNA was extracted from greater omentum biopsies, and, using a DNA microarray, differential transcriptomic expression of VAT in women with obesity was evaluated taking as a reference that of women with normal weight. The differentially expressed genes (DEGs) were classified into functional biological processes and signaling pathways; moreover, the protein-protein interaction (PPI) networks were integrated for a deeper analysis of the pathways and genes involved in the central obesity-associated disorders. The expression of TNF-α, MAPK, and AKT proteins was also quantified in VAT. Results: The VAT of women with obesity had 3808 DEGs, mainly associated with the cellular process of inflammation and carbohydrates and lipid metabolism. Overexpressed genes were associated with inflammatory, metabolic, hormonal, neuroendocrine, carcinogenic, and infectious pathways. Cellular processes related to addictive behaviors were notable. MAPK and PI3K-AKT pathways were overexpressed, and Mapk1 and Akt3 genes were common crossing points among obesity-associated disorders' pathways. The increased expression of MAPK, AKT, and TNF proteins was confirmed in the VAT of women with obesity. Conclusion: VAT confers a complex and blended pathogenic transcriptomic profile in obese patients, where abnormal processes are mainly controlled by activating intracellular signaling pathways that exhibit a high degree of redundancy. Identifying shared cross points between those pathways could allow specific targeting treatments to exert a widespread effect over multiple pathogenic processes.

Targeting the RAS upstream and downstream signaling pathway for cancer treatment

Cancer often involves the overactivation of RAS/RAF/MEK/ERK (MAPK) and PI3K-Akt-mTOR pathways due to mutations in genes like RAS, RAF, PTEN, and PIK3CA. Various strategies are employed to address the overactivation of these pathways, among which targeted therapy emerges as a promising approach. Directly targeting specific proteins, leads to encouraging results in cancer treatment. For instance, RTK inhibitors such as imatinib and afatinib selectively target these receptors, hindering ligand binding and reducing signaling initiation. These inhibitors have shown potent efficacy against Non-Small Cell Lung Cancer. Other inhibitors, like lonafarnib targeting Farnesyltransferase and GGTI 2418 targeting geranylgeranyl Transferase, disrupt post-translational modifications of proteins. Additionally, inhibition of proteins like SOS, SH2 domain, and Ras demonstrate promising anti-tumor activity both in vivo and in vitro. Targeting downstream components with RAF inhibitors such as vemurafenib, dabrafenib, and sorafenib, along with MEK inhibitors like trametinib and binimetinib, has shown promising outcomes in treating cancers with BRAF-V600E mutations, including myeloma, colorectal, and thyroid cancers. Furthermore, inhibitors of PI3K (e.g., apitolisib, copanlisib), AKT (e.g., ipatasertib, perifosine), and mTOR (e.g., sirolimus, temsirolimus) exhibit promising efficacy against various cancers such as Invasive Breast Cancer, Lymphoma, Neoplasms, and Hematological malignancies. This review offers an overview of small molecule inhibitors targeting specific proteins within the RAS upstream and downstream signaling pathways in cancer.

Anticancer potential of phytochemicals derived from mangrove plants: Comprehensive mechanistic insights

Cancer is a collection of illnesses characterized by aberrant cellular proliferation that can infiltrate or metastasize to distant anatomical sites, posing a notable threat to human well-being due to its substantial morbidity and death rates worldwide. The potential of plant-derived natural compounds as anticancer medicines has been assessed owing to their favorable attributes of few side effects and significant antitumor activity. Mangrove plants and their derived compounds have been scientifically shown to exhibit many significant beneficial biological activities, such as anti-inflammatory, immunomodulatory, antioxidant, neuroprotective, cardioprotective, and hepatoprotective properties. This study summarized mangrove plants and their derived compounds as potential anticancer agents, with an emphasis on the underlying molecular mechanisms. To explore this, we gathered data on the preclinical (in vivo and in vitro) anticancer effects of mangrove plants and their derived compounds from reputable literature spanning 2000 to 2023. We conducted thorough searches in various academic databases, including PubMed, ScienceDirect, Wiley Online, SpringerLink, Google Scholar, Scopus, and the Web of Science. The results demonstrated that mangrove plants and their derived compounds have promising anticancer properties in preclinical pharmacological test systems through various molecular mechanisms, including induction of oxidative stress and mitochondrial dysfunction, cytotoxicity, genotoxicity, cell cycle arrest, apoptosis, autophagy, antiproliferative, antimetastatic, and other miscellaneous actions. Upon thorough observation of the pertinent information, it is suggested that mangrove plants and their derived chemicals may serve as a potential lead in the development of novel drugs for cancer therapy.

Anticancer potential of Diospyrin and its analogues: An updated review

Cancer, characterized as one of the leading causes of death owing to its heterogeneity and complexity, hence poses a significant challenge to health care system across the globe. Current therapies for cancer curtailment are considered to have associated side effects, therefore discovery of novel alternative approaches is need of the time. In this context, natural products have attained an essential spot in the scientific community for the development of novel cancer treatments. Among others, Diospyrin, a bis-hydroxy-naphthoquinonoid, is a vital bioactive component present in various Diospyros and Euclea species. The bioactivity associated with Diospyrin's makes it a promising "lead molecule" for new chemotherapy. In this review, biosynthesis of Diospyrin and its analogues along with their anticancer activities has been discussed. Moreover, this review briefly discusses probable modes of action of Diospyrin and its analogues by targeting the molecular signal transduction pathways. This review also highlights the toxicological and clinical implications of diospyrin and its derivatives. Further pharmacological and pharmacogenetic studies are required to better understand the anticancer potential of Diospyrin and its analogues at the molecular and genetic levels.

Baculovirus-mediated endostatin and angiostatin activation of autophagy through the AMPK/AKT/mTOR pathway inhibits angiogenesis in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a highly vascularized carcinoma, and targeting its neovascularization represents an effective therapeutic approach. Our previous study demonstrated that the baculovirus-mediated endostatin and angiostatin fusion protein (BDS-hEA) effectively inhibits the angiogenesis of vascular endothelial cells and the growth of HCC tumors. However, the mechanism underlying its anti-angiogenic effect remains unclear. Increasing evidence suggests that autophagy has a significant impact on the function of vascular endothelial cells and response to cancer therapy. Hence, the objective of this research was to investigate the correlation between BDS-hEA-induced angiogenesis inhibition and autophagy, along with potential regulatory mechanisms. Our results demonstrated that BDS-hEA induced autophagy in EA.hy926 cells, as evidenced by the increasing number of autophagosomes and reactive oxygen species, accompanied by an upregulation of Beclin-1, LC3-II/LC3-I, and p62 protein expression. Suppression of autophagy using 3-methyladenine attenuated the functions of BDS-hEA-induced EA.hy926 cells, including the viability, proliferation, invasion, migration, and angiogenesis. Moreover, BDS-hEA induced autophagy by downregulating the expression of CD31, VEGF, and VEGFR2, as well as phosphorylated protein kinase B (p-AKT) and phosphorylated mammalian target of rapamycin (p-mTOR), while concurrently upregulating phosphorylated AMP-activated protein kinase (p-AMPK). The in vivo results further indicated that inhibition of autophagy by chloroquine significantly impeded the ability of BDS-hEA to suppress HCC tumor growth in mice. Mechanistically, BDS-hEA prominently facilitated autophagic apoptosis in tumor tissues and decreased the levels of ki67, CD31, VEGF, MMP-9, p-AKT, and p-mTOR while simultaneously enhancing the p-AMPK expression. In conclusion, our findings suggest that BDS-hEA induces autophagy as a cytotoxic response by modulating the AMPK/AKT/mTOR signaling pathway, thereby exerting anti-angiogenic effects against HCC.

Hypoxia-associated autophagy flux dysregulation in human cancers

A general feature of cancer is hypoxia, determined as low oxygen levels. Low oxygen levels may cause cells to alter in ways that contribute to tumor growth and resistance to treatment. Hypoxia leads to variations in cancer cell metabolism, angiogenesis and metastasis. Furthermore, a hypoxic tumor microenvironment might induce immunosuppression. Moreover, hypoxia has the potential to impact cellular processes, such as autophagy. Autophagy refers to the catabolic process by which damaged organelles and toxic macromolecules are broken down. The abnormal activation of autophagy has been extensively recorded in human tumors and it serves as a regulator of cell growth, spread to other parts of the body, and resistance to treatment. There is a correlation between hypoxia and autophagy in human malignancies. Hypoxia can regulate the activity of AMPK, mTOR, Beclin-1, and ATGs to govern autophagy in human malignancies. Furthermore, HIF-1α, serving as an indicator of low oxygen levels, controls the process of autophagy. Hypoxia-induced autophagy has a crucial role in regulating the growth, spread, and resistance to treatment in human malignancies. Hypoxia-induced regulation of autophagy can impact other mechanisms of cell death, such as apoptosis. Chemoresistance and radioresistance have become significant challenges in recent years. Hypoxia-mediated autophagy plays a crucial role in determining the response to these therapeutic treatments.

The potential role of circular RNAs -regulated PI3K signaling in non-small cell lung cancer: Molecular insights and clinical perspective

Non-small cell lung cancer (NSCLC), accounting for more than 80% of all cases, is the predominant form of lung cancer and the leading cause of cancer-related deaths worldwide. Significant progress has been made in diagnostic techniques, surgical interventions, chemotherapy protocols, and targeted therapies at the molecular level, leading to enhanced treatment outcomes in patients with NSCLC. Extensive evidence supports the use of circular RNAs (circRNAs), a specific category of naturally occurring non-coding small RNAs (ncRNAs), for the diagnosis, monitoring of treatment efficacy, and assessment of survival in NSCLC. CircRNAs have been identified to play significant roles in various aspects of cancer formation, either as tumor suppressors or tumor promoters, contributing to cancer development through several signaling pathways, including the phosphoinositide 3-kinases (PI3Ks) pathway. This pathway is well-established because of its regulatory role in essential cellular processes. CircRNAs regulate the PI3K/AKT pathway by targeting diverse cellular elements. This review aims to provide insight into the involvement of several circRNAs linked to the PI3K/AKT pathway in NSCLC.

In vivo evaluation of mebendazole and Ran GTPase inhibition in breast cancer model system

Aim: To investigate the therapeutic potential of mebendazole (MBZ)-loaded nanostructured lipid carriers (NLCs). Methodology: NLC-MBZ was prepared and characterized to evaluate the in vitro and in vivo anticancer effects and the inhibitory effect on RanGTP and its potential as an antimetastatic treatment in vivo. Results: NLC-MBZ exhibited a size and charge of 155 ± 20 nm and -27 ± 0.5 mV, respectively, with 90.7% encapsulation. Free MBZ and NLC-MBZ had a 50% inhibitory concentration of 610 and 305 nM, respectively, against MDA-MB-231 cell lines. NLC-MBZ decreased tumor size, suppressed tumor lung metastases, and lowered the expression of CDC25A, SKP2, RbX1 and Cullin1 while boosting the Rb proteins. Conclusion: NLC-MBZ displayed antiangiogenic potential and resulted in a reduced rate of lung metastasis in vivo.

Dual-loaded liposomal carriers to combat chemotherapeutic resistance in breast cancer

INTRODUCTION

The resistance to chemotherapy is a significant hurdle in breast cancer treatment, prompting the exploration of innovative strategies. This review discusses the potential of dual-loaded liposomal carriers to combat chemoresistance and improve outcomes for breast cancer patients.

AREAS COVERED

This review discusses breast cancer chemotherapy resistance and dual-loaded liposomal carriers. Drug efflux pumps, DNA repair pathways, and signaling alterations are discussed as chemoresistance mechanisms. Liposomes can encapsulate several medicines and cargo kinds, according to the review. It examines how these carriers improve medication delivery, cancer cell targeting, and tumor microenvironment regulation. Also examined are dual-loaded liposomal carrier improvement challenges and techniques.

EXPERT OPINION

The use of dual-loaded liposomal carriers represents a promising and innovative strategy in the battle against chemotherapy resistance in breast cancer. This article has explored the various mechanisms of chemoresistance in breast cancer, emphasizing the potential of dual-loaded liposomal carriers to overcome these challenges. These carriers offer versatility, enabling the encapsulation and precise targeting of multiple drugs with different modes of action, a crucial advantage when dealing with the complexity of breast cancer treatment.

Multifaceted role of mTOR (mammalian target of rapamycin) signaling pathway in human health and disease

The mammalian target of rapamycin (mTOR) is a protein kinase that controls cellular metabolism, catabolism, immune responses, autophagy, survival, proliferation, and migration, to maintain cellular homeostasis. The mTOR signaling cascade consists of two distinct multi-subunit complexes named mTOR complex 1/2 (mTORC1/2). mTOR catalyzes the phosphorylation of several critical proteins like AKT, protein kinase C, insulin growth factor receptor (IGF-1R), 4E binding protein 1 (4E-BP1), ribosomal protein S6 kinase (S6K), transcription factor EB (TFEB), sterol-responsive element-binding proteins (SREBPs), Lipin-1, and Unc-51-like autophagy-activating kinases. mTOR signaling plays a central role in regulating translation, lipid synthesis, nucleotide synthesis, biogenesis of lysosomes, nutrient sensing, and growth factor signaling. The emerging pieces of evidence have revealed that the constitutive activation of the mTOR pathway due to mutations/amplification/deletion in either mTOR and its complexes (mTORC1 and mTORC2) or upstream targets is responsible for aging, neurological diseases, and human malignancies. Here, we provide the detailed structure of mTOR, its complexes, and the comprehensive role of upstream regulators, as well as downstream effectors of mTOR signaling cascades in the metabolism, biogenesis of biomolecules, immune responses, and autophagy. Additionally, we summarize the potential of long noncoding RNAs (lncRNAs) as an important modulator of mTOR signaling. Importantly, we have highlighted the potential of mTOR signaling in aging, neurological disorders, human cancers, cancer stem cells, and drug resistance. Here, we discuss the developments for the therapeutic targeting of mTOR signaling with improved anticancer efficacy for the benefit of cancer patients in clinics.

Pharmacological effects and mechanisms of paeonol on antitumor and prevention of side effects of cancer therapy

Cancer represents one of the leading causes of mortality worldwide. Conventional clinical treatments include radiation therapy, chemotherapy, immunotherapy, and targeted therapy. However, these treatments have inherent limitations, such as multidrug resistance and the induction of short- and long-term multiple organ damage, ultimately leading to a significant decrease in cancer survivors' quality of life and life expectancy. Paeonol, a nature active compound derived from the root bark of the medicinal plant Paeonia suffruticosa, exhibits various pharmacological activities. Extensive research has demonstrated that paeonol exhibits substantial anticancer effects in various cancer, both in vitro and in vivo. Its underlying mechanisms involve the induction of apoptosis, the inhibition of cell proliferation, invasion and migration, angiogenesis, cell cycle arrest, autophagy, regulating tumor immunity and enhanced radiosensitivity, as well as the modulation of multiple signaling pathways, such as the PI3K/AKT and NF-κB signaling pathways. Additionally, paeonol can prevent adverse effects on the heart, liver, and kidneys induced by anticancer therapy. Despite numerous studies exploring paeonol's therapeutic potential in cancer, no specific reviews have been conducted. Therefore, this review provides a systematic summary and analysis of paeonol's anticancer effects, prevention of side effects, and the underlying mechanisms involved. This review aims to establish a theoretical basis for the adjunctive strategy of paeonol in cancer treatment, ultimately improving the survival rate and enhancing the quality of life for cancer patients.