Effects of combining rapamycin and resveratrol on apoptosis and growth of TSC2-deficient xenograft tumors

Structure based interaction and molecular dynamics studies of cysteine protease Cathepsin B against curcumin and resveratrol

The lysosomal cysteine peptidase Cathepsin B is identified as a pivotal contributor to cancer development. In the pursuit of discovering less toxic inhibitors for Cathepsin B, various organic compounds have undergone thorough investigation and are being studied at the moment in clinical studies for cancer treatment. Notably, curcumin and resveratrol emerge as prominent candidates. However, the precise molecular mechanism underlying the inhibition of Cathepsin B by these compounds remains elusive. To address this gap, we conducted molecular docking and dynamics studies to unravel the interaction dynamics between Cathepsin B and phytochemicals such as curcumin and resveratrol. Remarkably, Molecular docking studies revealed that curcumin and resveratrol exhibit high binding affinities 7.599 and 6.103 kcal/mol, respectively, positioning them as promising inhibitors for Cathepsin B. Further insights from 150 ns of molecular dynamics simulations, incorporating structural analyses encompassing RMSF, RMSD, Rg, SASA, and H-bond analysis, indicate the superior stability of curcumin compared to resveratrol. Additionally, we assessed their drug-likeness properties using the PreADMET web server, and the MM/BPSA method facilitated the calculation of binding energies for the complexes. On targeting Cathepsin B, this research promises to contribute to the development of drugs that inhibit the progression of cancer.

Repurposing Nitazoxanide for Potential Treatment of Rare Disease Lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is a rare genetic lung disease. Unfortunately, treatment with the mTORC1 inhibitor Rapamycin only slows disease progression, and incomplete responses are common. Thus, there remains an urgent need to identify new targets for the development of curative LAM treatments. Nitazoxanide (NTZ) is an orally bioavailable antiprotozoal small molecule drug approved for the treatment of diarrhea caused by Giardia lamblia or Cryptosporidium parvum in children and adults, with a demonstrated mTORC1 inhibitory effect in several human cell lines. NTZ's excellent safety profile characterized by its more than 20 years of clinical use makes it a promising candidate for repurposing. Our rationale for this study was to further investigate NTZ's effect using in vitro and in vivo LAM models and to elucidate the underlying molecular mechanism beyond mTORC1 inhibition. For this purpose, we investigated cell proliferation, cell viability, and changes in protein phosphorylation and expression in primary human cell cultures derived from LAM lung samples before translating our results into a syngeneic mouse model utilizing Tsc2-null cells. NTZ reduced cell growth for all tested cell lines at a dose of about 30 µM. Lower doses than that had no effect on cell viability, but doses above 45 µM lowered the viability by about 10 to 15% compared to control. Interestingly, our western blot revealed no inhibition of mTORC1 and only a mild effect on active ß-Catenin. Instead, NTZ had a pronounced effect on reducing pAkt. In the mouse model, prophylactic NTZ treatment via the intraperitoneal and oral routes had some effects on reducing lung lesions and improving body weight retention, but the results remain inconclusive.

The effect of resveratrol, curcumin and quercetin combination on immuno-suppression of tumor microenvironment for breast tumor-bearing mice

Resveratrol, curcumin, and quercetin are the secondary metabolites from medicinal food homology plants, that have been proven their potency in cancer treatment. However, the antitumor effect of a single component is weak. So, herein, we designed an antitumor compound named RCQ composed of resveratrol, curcumin, and quercetin. This study examined the effect on tumorigenesis and development of 4T1 breast cancer-bearing mice following administering RCQ by intragastric administration. RCQ increased the recruitment of T cells and reduced the accumulation of neutrophils and macrophages in the tumor microenvironment. Meanwhile, RCQ suppressed the development of tumor-infiltrating lymphocytes into immunosuppressive cell subpopulations, including CD4+ T cells to T helper Type 2 type (Th2), tumor-associated neutrophils (TANs) to the N2 TANs, and tumor-associated macrophages (TAMs) cells to M2 TAMs. RCQ reversed the predominance of immunosuppressive infiltrating cells in the tumor microenvironment and tipped the immune balance toward an immune activation state. In vitro the study showed that RCQ significantly increased reactive oxygen species (ROS), reduce mitochondrial membrane potentials in cancer cells, and modulate pro-apoptotic Bcl-2 family members. In conclusion, RCQ can promote the ROS apoptosis mechanism of tumor cells and alleviate immunosuppression of the tumor microenvironment to enhance the anti-tumor effect.

Resistance to anti-HER2 therapy associated with the TSC2 nonsynonymous variant c.4349 C > G (p.Pro1450Arg) is reversed by CDK4/6 inhibitor in HER2-positive breast cancer

HER2-positive breast cancer patients carrying the germline TSC2 nonsynonymous variant c.4349 C > G (p.Pro1450Arg) are resistant to anti-HER2 therapy. Multi-predictor in silico analysis reveals that this variant is deleterious. We explore the potential mechanism of this TSC2 variant and investigate methods for overcoming anti-HER2 resistance. TSC2 c.4349 C > G reverses the inhibitory effect on mTOR and downstream signaling by increasing TSC2 phosphorylation at Thr1462 and confers significant lapatinib resistance in vitro and in vivo. The combination of lapatinib and the CDK4/6 inhibitor palbociclib inhibits cyclin D1/CDK4/Rb alternative pathway and TSC2 phosphorylation, thereby partially attenuating mTOR activity and inducing TSC2-mutant cell blockage at G1/G0. In in vitro and xenograft models, palbociclib+lapatinib shows higher anti-tumor activity than monotherapy and overcomes the resistance of the TSC2 c.4349 C > G-related variant to anti-HER2 therapy. We reveal a new mechanism of resistance to anti-HER2 therapy and provide a strategy to increase the efficiency of anti-HER2 therapy in HER2-positive breast cancer.

Safety and Efficacy of Combined Resveratrol and Sirolimus in Lymphangioleiomyomatosis

BACKGROUND

A critical need exists to develop remission-inducing therapies for lymphangioleiomyomatosis.

RESEARCH QUESTION

Is the addition of resveratrol safe and more efficacious than sirolimus alone in patients with lymphangioleiomyomatosis?

STUDY DESIGN AND METHODS

We conducted a phase 2, dose-escalating, open-label trial of resveratrol in patients with lymphangioleiomyomatosis receiving a stable regimen of sirolimus. Resveratrol was started at 250 mg/d and escalated every 8 weeks to maximum dose of 1,000 mg/d over 24 weeks. The primary outcome was ≥ 42% decline in serum vascular endothelial growth factor D (VEGF-D) levels on combined therapy compared with baseline VEGF-D levels on sirolimus. Secondary objectives included an assessment of the safety profile and the effect on lung function and health-related quality of life (HRQOL). Longitudinal change in outcome measures was assessed using linear mixed models. Adverse effects were tabulated using the National Cancer Institute's Common Terminology Criteria for Adverse Events version 4.

RESULTS

Twenty-five patients with lymphangioleiomyomatosis with a median age of 51 years were enrolled. Pulmonary function parameters at study inclusion were: FEV1: median absolute, 1.72 L; 64% predicted; FVC: median absolute, 2.99 L; 96% predicted; and diffusing capacity of the lungs for carbon monoxide: median absolute, 14.68 mL/mm Hg/min; 37% predicted. The median serum VEGF-D value at baseline was 617 pg/mL. Patients entered the study with a median sirolimus dose of 2 mg/d with median trough level of 6.3 ng/mL. Despite some GI side effects, the addition of resveratrol was well tolerated. Although the primary outcome was not met, a statistically significant reduction in serum VEGF-D levels and improvement in HRQOL during the study was found.

INTERPRETATION

The addition of resveratrol was safe and well tolerated in patients with lymphangioleiomyomatosis taking sirolimus and was associated with modest improvement in HRQOL. Larger controlled trials of this combination might be warranted to assess definitively the usefulness of resveratrol as an additive therapy in lymphangioleiomyomatosis.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT03253913; URL: www.

CLINICALTRIALS

gov.

The paradox of autophagy in Tuberous Sclerosis Complex

Tuberous sclerosis complex (TSC) is an autosomal dominant genetic disorder caused by germline mutations in TSC1 or TSC2 genes, which leads to the hyperactivation of the mTORC1 pathway, an important negative regulator of autophagy. This leads to the development of hamartomas in multiple organs. The variability in symptoms presents a challenge for the development of completely effective treatments for TSC. One option is the treatment with mTORC1 inhibitors, which are targeted to block cell growth and restore autophagy. However, the therapeutic effect of rapamycin seems to be more efficient in the early stages of hamartoma development, an effect that seems to be associated with the paradoxical role of autophagy in tumor establishment. Under normal conditions, autophagy is directly inhibited by mTORC1. In situations of bioenergetics stress, mTORC1 releases the Ulk1 complex and initiates the autophagy process. In this way, autophagy promotes the survival of established tumors by supplying metabolic precursors during nutrient deprivation; paradoxically, excessive autophagy has been associated with cell death in some situations. In spite of its paradoxical role, autophagy is an alternative therapeutic strategy that could be explored in TSC. This review compiles the findings related to autophagy and the new therapeutic strategies targeting this pathway in TSC.

Fanconi anemia and mTOR pathways functionally interact during stalled replication fork recovery

We have previously demonstrated that Fanconi anemia (FA) proteins work in concert with other FA and non-FA proteins to mediate stalled replication fork restart. Previous studies suggest a connection between the FA protein FANCD2 and the non-FA protein mechanistic target of rapamycin (mTOR). A recent study showed that mTOR is involved in actin-dependent DNA replication fork restart, suggesting possible roles in the FA DNA repair pathway. In this study, we demonstrate that during replication stress mTOR interacts and cooperates with FANCD2 to provide cellular stability, mediate stalled replication fork restart, and prevent nucleolytic degradation of the nascent DNA strands. Taken together, this study unravels a novel functional cross-talk between two important mechanisms: mTOR and FA DNA repair pathways that ensure genomic stability.

Resveratrol attenuates stimulated T-cell activation and proliferation: potential therapy against cellular rejection in organ transplantation

BACKGROUND

Pharmaceuticals to inhibit mammalian target of rapamycin (mTOR) protein, which plays an integral role in T cell survival and function, have been used to prevent complications associated with organ transplantation. Although studies have individually shown that resveratrol can inhibit mTOR and that inhibiting mTOR leads to attenuated immune function, no studies to date have examined these two functions conjointly under one study. Therefore, we hypothesize that resveratrol will decrease mTOR activation and expression as well as attenuate stimulated T cell activation and proliferation in peripheral blood mononuclear cells (PBMC).

METHODS AND MATERIALS

Human PBMC were isolated and cultured. The cells were pre-treated with resveratrol (50 μM) overnight (18 hrs) before stimulation. The cells were collected for subsequent biochemical analysis after 1, 3, and 5 days. Additionally, the cells were stained with proliferation dye and cultured for 24 hours in PMA/Ionomycin with resveratrol for flow cytometry analysis.

RESULTS

Resveratrol treated stimulated PBMCs displayed a significant decrease in activated phosphorylation of mTOR at days 1, 3, and 5 (P < 0.0329). Markers of T cell activation, tumour necrosis factor-alpha (TNF-α) and interferon-gamma (INF-γ), were also significantly reduced along with T cell proliferation following stimulated PBMC resveratrol treatment when compared to vehicle-treated controls (P < 0.01).

CONCLUSION

Taken together, our data suggest that resveratrol can decrease the immune response of stimulated T-cells and inhibit the expression and activation of mTOR mediated cellular signalling under the same study setting. Therefore, resveratrol proposes a possible adjunctive therapy option for patients undergoing organ transplantation.

Possible Novel Therapeutic Targets in Lymphangioleiomyomatosis Treatment

Lymphangioleiomyomatosis (LAM) is a rare systemic neoplastic disease that exclusively happens in women. Studies focusing on LAM and tuberous sclerosis complex (TSC) have made great progress in understanding the pathogenesis and searching for treatment. The inactive mutation of TSC1 or TSC2 is found in patients with LAM to activate the crucial mammalian target of rapamycin (mTOR) signaling pathway and result in enhanced cell proliferation and migration. However, it does not explain every step of tumorigenesis in LAM. Because cessation of rapamycin would break the stabilization of lung function or improved quality of life and lead to disease recurrent, continued studies on the pathogenesis of LAM are necessary to identify novel targets and new treatment. Researchers have found several aberrant regulations that affect the mTOR pathway such as its upstream or downstream molecules and compensatory pathways in LAM. Some therapeutic targets have been under study in clinical trials. New methods like genome-wide association studies have located a novel gene related to LAM. Herein, we review the current knowledge regarding pathogenesis and treatment of LAM and summarize novel targets of therapeutic potential recently.

A Brief Review of Nutraceutical Ingredients in Gastrointestinal Disorders: Evidence and Suggestions

The dietary effect on gut health has long been recognized through the empirical practice of soothing gastric discomfort with certain types of food, and recently the correlation between specific diets with lower incidences of several gastrointestinal diseases has been revealed. Ingredients from those considered beneficial foods have been isolated and studied, and some of them have already been put into the supplement market. In this review, we focus on latest studies of these food-derived ingredients for their proposed preventive and therapeutic roles in gastrointestinal disorders, with the attempt of drawing evidence-based suggestions on consuming these products.

Functional interaction between Fanconi anemia and mTOR pathways during stalled replication fork recovery.. [DOI: 10.1101/2020.01.16.899211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

We have previously demonstrated that Fanconi Anemia (FA) proteins work in concert with other FA and non-FA proteins to mediate stalled replication fork restart. Previous studies suggest a connection between FA protein FANCD2 and a non-FA protein mechanistic target of rapamycin (mTOR). A recent study showed that mTOR is involved in actin-dependent DNA replication fork restart, suggesting possible roles in FA DNA repair pathway. In this study, we demonstrate that during replication stress mTOR interacts and cooperates with FANCD2 to provide cellular stability, mediates stalled replication fork restart and prevents nucleolytic degradation of the nascent DNA strands. Taken together, this study unravels a novel functional cross-talk between two important mechanisms: mTOR and FA DNA repair pathways that ensure genomic stability.

Autophagy in Human Health and Disease: Novel Therapeutic Opportunities

SIGNIFICANCE

In eukaryotes, autophagy represents a highly evolutionary conserved process, through which macromolecules and cytoplasmic material are degraded into lysosomes and recycled for biosynthetic or energetic purposes. Dysfunction of the autophagic process has been associated with the onset and development of many human chronic pathologies, such as cardiovascular, metabolic, and neurodegenerative diseases as well as cancer. Recent Advances: Currently, comprehensive research is being carried out to discover new therapeutic agents that are able to modulate the autophagic process in vivo. Recent evidence has shown that a large number of natural bioactive compounds are involved in the regulation of autophagy by modulating several transcriptional factors and signaling pathways.

CRITICAL ISSUES

Critical issues that deserve particular attention are the inadequate understanding of the complex role of autophagy in disease pathogenesis, the limited availability of therapeutic drugs, and the lack of clinical trials. In this context, the effects that natural bioactive compounds exert on autophagic modulation should be clearly highlighted, since they depend on the type and stage of the pathological conditions of diseases.

FUTURE DIRECTIONS

Research efforts should now focus on understanding the survival-supporting and death-promoting roles of autophagy, how natural compounds interact exactly with the autophagic targets so as to induce or inhibit autophagy and on the evaluation of their pharmacological effects in a more in-depth and mechanistic way. In addition, clinical studies on autophagy-inducing natural products are strongly encouraged, also to highlight some fundamental aspects, such as the dose, the duration, and the possible synergistic action of these compounds with conventional therapy.

mTOR Signaling and Neural Stem Cells: The Tuberous Sclerosis Complex Model

The mechanistic target of rapamycin (mTOR), a serine-threonine kinase, plays a pivotal role in regulating cell growth and proliferation. Notably, a great deal of evidence indicates that mTOR signaling is also crucial in controlling proliferation and differentiation of several stem cell compartments. Consequently, dysregulation of the mTOR pathway is often associated with a variety of disease, such as cancer and metabolic and genetic disorders. For instance, hyperactivation of mTORC1 in neural stem cells (NSCs) is associated with the insurgence of neurological manifestation characterizing tuberous sclerosis complex (TSC). In this review, we survey the recent contributions of TSC physiopathology studies to understand the role of mTOR signaling in both neurogenesis and tumorigenesis and discuss how these new insights can contribute to developing new therapeutic strategies for neurological diseases and cancer.

Comprehensive review on the antimicrobial potency of the plant polyphenol Resveratrol

Treatment of some infectious diseases are becoming more complicated because of increasing drug resistance rate and lack of proper antibiotics. Because of the rapid increase in drug-resistance trend, there is an urgent need for alternative microbicides to control infectious diseases. Resveratrol (RSV) is a small plant polyphenol that is naturally produced and distributed in 72 particular families of plants. The usage of natural derivatives such as RSV, have become popular among researchers for curing acute and chronic diseases. The purpose of the preset study was to comprehensively review and survey the antimicrobial potency of RSV. The present study demonstrates RSV as a natural antimicrobial agent.

The therapeutic potential of resveratrol: a review of clinical trials

Resveratrol is a nutraceutical with several therapeutic effects. It has been shown to mimic effects of caloric restriction, exert anti-inflammatory and anti-oxidative effects, and affect the initiation and progression of many diseases through several mechanisms. While there is a wealth of in vitro and in vivo evidence that resveratrol could be a promising therapeutic agent, clinical trials must confirm its potential. In this work, we reviewed the current clinical data available regarding the pharmacological action of resveratrol. Most of the clinical trials of resveratrol have focused on cancer, neurological disorders, cardiovascular diseases, diabetes, non-alcoholic fatty liver disease (NAFLD), and obesity. We found that for neurological disorders, cardiovascular diseases, and diabetes, the current clinical trials show that resveratrol was well tolerated and beneficially influenced disease biomarkers. However resveratrol had ambiguous and sometimes even detrimental effects in certain types of cancers and in NAFLD. In most of the clinical trials, the major obstacle presented was resveratrol’s poor bioavailability. Thus, this work provides useful considerations for the planning and design of future pre-clinical and clinical research on resveratrol.

Recent Advances and Challenges of mTOR Inhibitors Use in the Treatment of Patients with Tuberous Sclerosis Complex

Tuberous sclerosis complex (TSC) is a genetic condition characterized by the presence of benign, noninvasive, and tumor-like lesions called hamartomas that can affect multiple organ systems and are responsible for the clinical features of the disease. In the majority of cases, TSC results from mutations in the TSC1 and TSC2 genes, leading to the overactivation of the mammalian target of rapamycin (mTOR) signalling pathway, which controls several cell functions, including cell growth, proliferation, and survival. The establishment of a connection between TSC and mTOR led to the clinical use of drugs known as mTOR inhibitors (like rapamycin, also known as sirolimus and everolimus), which are becoming an increasingly interesting tool in the management of TSC-associated features, such as subependymal giant cell astrocytomas, renal angiomyolipomas, and also epilepsy. However, the intrinsic characteristics of these drugs and their systemic effects in such a heterogeneous condition pose many challenges in clinical practice, so that some questions remain unanswered. This article provides an overview of the pharmacological aspects of mTOR inhibitors about the clinical trials leading to their approval in TSC-related conditions and exposes current challenges and future directions associated with this promising therapeutic line.

Mourning Dr. Alfred G. Knudson: the two-hit hypothesis, tumor suppressor genes, and the tuberous sclerosis complex

On July 10, 2016, Alfred G. Knudson, Jr., MD, PhD, a leader in cancer research, died at the age of 93 years. We deeply mourn his loss. Knudson's two-hit hypothesis, published in 1971, has been fundamental for understanding tumor suppressor genes and familial tumor-predisposing syndromes. To understand the molecular mechanism of two-hit-initiated tumorigenesis, Knudson used an animal model of a dominantly inherited tumor, the Eker rat. From the molecular identification of Tsc2 germline mutations, the Eker rat became a model for tuberous sclerosis complex (TSC), a familial tumor-predisposing syndrome. Animal models, including the fly, have greatly contributed to TSC research. Because the product of the TSC2/Tsc2 gene (tuberin) together with hamartin, the product of another TSC gene (TSC1/Tsc1), suppresses mammalian/mechanistic target of rapamycin complex 1 (mTORC1), rapalogs have been used as therapeutic drugs for TSC. Although significant activity of these drugs has been reported, there are still problems such as recurrence of residual tumors and adverse effects. Recent studies indicate that there are mTORC1-independent signaling pathways downstream of hamartin/tuberin, which may represent new therapeutic targets. The establishment of cellular models, such as pluripotent stem cells with TSC2/Tsc2 gene mutations, will facilitate the understanding of new aspects of TSC pathogenesis and the development of novel treatment options. In this review, we look back at the history of Knudson and animal models of TSC and introduce recent progress in TSC research.

mTOR inhibitors in urinary bladder cancer

Despite the great scientific advances that have been made in cancer treatment, there is still much to do, particularly with regard to urinary bladder cancer. Some of the drugs used in urinary bladder cancer treatment have been in use for more than 30 years and show reduced effectiveness and high recurrence rates. There have been several attempts to find new and more effective drugs, to be used alone or in combination with the drugs already in use, in order to overcome this situation.The biologically important mammalian target of rapamycin (mTOR) pathway is altered in cancer and mTOR inhibitors have raised many expectations as potentially important anticancer drugs. In this article, the authors will review the mTOR pathway and present their experiences of the use of some mTOR inhibitors, sirolimus, everolimus and temsirolimus, in isolation and in conjunction with non-mTOR inhibitors cisplatin and gemcitabine, on urinary bladder tumour cell lines. The non-muscle-invasive cell line, 5637, is the only one that exhibits a small alteration in the mTOR and AKT phosphorylation after rapalogs exposure. Also, there was a small inhibition of cell proliferation. With gemcitabine plus everolimus or temsirolimus, the results were encouraging as a more effective response was noticed with both combinations, especially in the 5637 and T24 cell lines. Cisplatin associated with everolimus or temsirolimus also gave promising results, as an antiproliferative effect was observed when the drugs were associated, in particular on the 5637 and HT1376 cell lines. Everolimus or temsirolimus in conjunction with gemcitabine or cisplatin could have an important role to play in urinary bladder cancer treatment, depending on the tumour grading.

Resveratrol as a novel treatment for diseases with mTOR pathway hyperactivation

The mechanistic target of rapamycin complex 1 (mTORC1) signaling pathway is hyperactivated in a variety of cancers and tumor syndromes. Therefore, mTORC1 inhibitors are being actively investigated for treatment of neoplasms. The concern with the monotherapy use of mTORC1 inhibitors, such as rapamycin, is that they cause upregulation of autophagy, a cell survival mechanism, and suppress the negative feedback loop to the oncogene Akt. In turn, Akt promotes cell survival, causing the therapy to be partially effective, but relapse occurs upon cessation of treatment. In this review, we describe the current literature on resveratrol as well as our work, which uses rapamycin in combination with resveratrol. We found that this combination treatment efficiently blocked upregulation of autophagy and restored inhibition of Akt in different cancer and tumor models. Interestingly, the combination of rapamycin and resveratrol selectively promoted apoptosis of cells with mTOR pathway hyperactivation. Moreover, this combination prevented tumor growth and lung metastasis when tested in mouse models. Finally, mass spectrometry-based identification of cellular targets of resveratrol provided mechanistic insight into the mode of action of resveratrol. The addition of resveratrol to rapamycin treatment may be a promising option for selective and targeted therapy for diseases with mTORC1 hyperactivation.