scholarly journals The Bumpy Road towards mTOR Inhibition in Glioblastoma: Quo Vadis?

Biomedicines ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 1809
Author(s):  
Kostas A. Papavassiliou ◽  
Athanasios G. Papavassiliou
Keyword(s):  
Clinical Trials ◽  
First Generation ◽  
Treatment Options ◽  
Mtor Inhibitors ◽  
Mtor Inhibition ◽  
Mechanistic Target Of Rapamycin ◽  
Downstream Effects ◽  
Heterogeneous Nature ◽  
Quo Vadis ◽  
Clinical Potential

Glioblastoma multiforme (GBM), a grade IV astrocytoma, is a lethal brain tumor with a poor prognosis. Despite recent advances in the molecular biology of GBM, neuro-oncologists have very limited treatment options available to improve the survival of GBM patients. A prominent signaling pathway implicated in GBM pathogenesis is that of the mechanistic target of rapamycin (mTOR). Attempts to target the mTOR pathway with first-generation mTOR inhibitors appeared promising in the preclinical stage; however, results have been disappointing in clinical trials, owing to the heterogeneous nature of GBM, escape mechanisms against treatment, the blood–brain barrier, drug-related toxicities, and the imperfect design of clinical trials, among others. The development of next-generation mTOR inhibitors and their current evaluation in clinical trials have sparked new hope to realize the clinical potential of mTOR inhibitors in GBM. Meanwhile, studies are continuously furthering our understanding of mTOR signaling dysregulation, its downstream effects, and interplay with other signaling pathways in GBM tumors. Therefore, it remains to be seen whether targeting mTOR in GBM will eventually prove to be fruitful or futile.

scholarly journals Deficiency in the Treatment Description of mTOR Inhibitor Resistance in Medulloblastoma, a Systematic Review

2021 ◽  
Vol 23 (1) ◽  
pp. 464
Author(s):  
Hajar Alammar ◽  
Rayan Nassani ◽  
Mana M. Alshehri ◽  
Alaa A. Aljohani ◽  
Bahauddeen M. Alrfaei
Keyword(s):  
Systematic Review ◽  
Clinical Trials ◽  
First Generation ◽  
Treatment Options ◽  
Pediatric Brain Tumor ◽  
Mtor Inhibitors ◽  
Malignant Cell ◽  
Phase I Clinical Trials ◽  
Inhibitor Resistance ◽  
Pediatric Brain

Medulloblastoma is a common fatal pediatric brain tumor. More treatment options are required to prolong survival and decrease disability. mTOR proteins play an essential role in the disease pathogenesis, and are an essential target for therapy. Three generations of mTOR inhibitors have been developed and are clinically used for immunosuppression and chemotherapy for multiple cancers. Only a few mTOR inhibitors have been investigated for the treatment of medulloblastoma and other pediatric tumors. The first-generation mTOR, sirolimus, temsirolimus, and everolimus, went through phase I clinical trials. The second-generation mTOR, AZD8055 and sapanisertib, suppressed medulloblastoma cell growth; however, limited studies have investigated possible resistance pathways. No clinical trials have been found to treat medulloblastoma using third-generation mTOR inhibitors. This systematic review highlights the mechanisms of resistance of mTOR inhibitors in medulloblastoma and includes IDO1, T cells, Mnk2, and eIF4E, as they prolong malignant cell survival. The findings promote the importance of combination therapy in medulloblastoma due to its highly resistant nature.

Abnormal mTOR Activation in Autism

2018 ◽  
Vol 41 (1) ◽  
pp. 1-23 ◽  
Author(s):  
Kellen D. Winden ◽  
Darius Ebrahimi-Fakhari ◽  
Mustafa Sahin
Keyword(s):  
Autism Spectrum Disorder ◽  
Clinical Trials ◽  
Mtor Inhibitors ◽  
Autism Spectrum ◽  
Energy Availability ◽  
Molecular Processes ◽  
Neurodevelopmental Outcomes ◽  
Mechanistic Target Of Rapamycin ◽  
Neuronal Processes ◽  
Growth Abnormalities

The mechanistic target of rapamycin (mTOR) is an important signaling hub that integrates environmental information regarding energy availability and stimulates anabolic molecular processes and cell growth. Abnormalities in this pathway have been identified in several syndromes in which autism spectrum disorder (ASD) is highly prevalent. Several studies have investigated mTOR signaling in developmental and neuronal processes that, when dysregulated, could contribute to the development of ASD. Although many potential mechanisms still remain to be fully understood, these associations are of great interest because of the clinical availability of mTOR inhibitors. Clinical trials evaluating the efficacy of mTOR inhibitors to improve neurodevelopmental outcomes have been initiated.

scholarly journals mTOR Inhibition Overcomes RSK3-mediated Resistance to BET Inhibitors in Small Cell Lung Cancer

2021 ◽  
Author(s):  
Anju Kumari ◽  
Lisa Gesumaria ◽  
Yan-Jin Liu ◽  
V Keith Hughitt ◽  
Xiaohu Zhang ◽  
...  
Keyword(s):  
Cell Lines ◽  
Drug Combination ◽  
Treatment Options ◽  
Mtor Inhibitors ◽  
Signaling Cascade ◽  
Antitumor Effects ◽  
Mtor Inhibition ◽  
Bet Inhibitors

Purpose: SCLC is a recalcitrant malignancy with limited treatment options. BET inhibitors have shown promising preclinical activity in SCLC, but their broad sensitivity spectrum limits their clinical prospects in this malignancy. Drug combination could be a solution. Experimental design: We performed high-throughput drug combination screens in SCLC cell lines to identify potential therapeutics synergizing with BET inhibitors. Validation was performed in SCLC cell lines and patient-derived xenograft models. Genome-wide RNA sequencing of xenograft tumors was performed to determine the mechanism underlying the synergy of the drug combination. Results: Inhibitors of the PI-3K-AKT-mTOR pathway were the top candidates from the screens. Among the therapeutics targeting this pathway, mTOR inhibitors showed the highest degree of synergy with BET inhibitors in vitro. Furthermore, the combination of these two classes of drugs showed superior antitumor efficacy and tolerability in vivo. Using both in vitro and in vivo SCLC models, we demonstrate that BET inhibitors activate the intrinsic apoptotic cascade, and mTOR inhibitors further enhance these apoptotic effects. Mechanistically, BET inhibitors activate the TSC2-mTOR-p70S6K1 signaling cascade by upregulating RSK3, an upstream kinase of TSC2. Activation of p70S6K1 leads to BAD phosphorylation and cell survival. mTOR inhibition blocks this survival signaling cascade and potentiates the antitumor effects of BET inhibitors. Conclusions: Our results demonstrate that RSK3 upregulation is a novel resistance mechanism of BET inhibitors in SCLC, and mTOR inhibition can overcome this resistance and enhance apoptosis. These findings provide a rationale to evaluate the combination of mTOR and BET inhibitors in patients with SCLC.

scholarly journals mTOR Inhibition: From Aging to Autism and Beyond

Scientifica ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-17 ◽  
Author(s):  
Matt Kaeberlein
Keyword(s):  
Mtor Inhibitors ◽  
Cellular Level ◽  
Mtor Signaling ◽  
Target Of Rapamycin ◽  
Mtor Inhibition ◽  
Pharmacological Modulation ◽  
Related Disease ◽  
Mechanistic Target Of Rapamycin ◽  
Age Related ◽  
Growing Body

The mechanistic target of rapamycin (mTOR) is a highly conserved protein that regulates growth and proliferation in response to environmental and hormonal cues. Broadly speaking, organisms are constantly faced with the challenge of interpreting their environment and making a decision between “grow or do not grow.” mTOR is a major component of the network that makes this decision at the cellular level and, to some extent, the tissue and organismal level as well. Although overly simplistic, this framework can be useful when considering the myriad functions ascribed to mTOR and the pleiotropic phenotypes associated with genetic or pharmacological modulation of mTOR signaling. In this review, I will consider mTOR function in this context and attempt to summarize and interpret the growing body of literature demonstrating interesting and varied effects of mTOR inhibitors. These include robust effects on a multitude of age-related parameters and pathologies, as well as several other processes not obviously linked to aging or age-related disease.

scholarly journals Sirolimus and Other Mechanistic Target of Rapamycin Inhibitors Directly Activate Latent Pathogenic Human Polyomavirus Replication

2020 ◽  
Author(s):  
Jennifer Alvarez Orellana ◽  
Hyun Jin Kwun ◽  
Sara Artusi ◽  
Yuan Chang ◽  
Patrick S Moore
Keyword(s):  
Dna Replication ◽  
Jc Virus ◽  
Mtor Inhibitors ◽  
Bk Virus ◽  
Target Of Rapamycin ◽  
Human Polyomavirus ◽  
Merkel Cell ◽  
Mtor Inhibition ◽  
Mechanistic Target Of Rapamycin ◽  
Transplant Patients

Abstract Background Human polyomaviruses can reactivate in transplant patients, causing nephropathy, progressive multifocal leukoencephalopathy, Merkel cell carcinoma, pruritic, rash or trichodysplasia spinulosa. Sirolimus and related mechanistic target of rapamycin (mTOR) inhibitors are transplant immunosuppressants. It is unknown if they directly reactivate polyomavirus replication from latency beyond their general effects on immunosuppression. Methods In vitro expression and turnover of large T (LT) proteins from BK virus, JC virus (JCV), Merkel cell polyomavirus (MCV), human polyomavirus 7 (HPyV7), and trichodysplasia spinulosa polyomavirus (TSV) after drug treatment were determined by immunoblotting, proximity ligation, replicon DNA replication, and whole virus immunofluorescence assays. Results mTOR inhibition increased LT protein expression for all 5 pathogenic polyomaviruses tested. This correlated with LT stabilization, decrease in the S-phase kinase-associated protein 2 (Skp2) E3 ligase targeting these LT proteins for degradation, and increase in virus replication for JCV, MCV, TSV, and HPyV7. Treatment with sirolimus, but not the calcineurin inhibitor tacrolimus, at levels routinely achieved in patients, resulted in a dose-dependent increase in viral DNA replication for BKV, MCV, and HPyV7. Conclusions mTOR inhibitors, at therapeutic levels, directly activate polyomavirus replication through a Skp2-dependent mechanism, revealing a proteostatic latency mechanism common to polyomaviruses. Modifying existing drug regimens for transplant patients with polyomavirus-associated diseases may reduce symptomatic polyomavirus replication while maintaining allograft-sparing immunosuppression.

scholarly journals Radiosensitising Cancer Using Phosphatidylinositol-3-Kinase (PI3K), Protein Kinase B (AKT) or Mammalian Target of Rapamycin (mTOR) Inhibitors

Cancers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1278 ◽  
Author(s):  
Kasun Wanigasooriya ◽  
Robert Tyler ◽  
Joao D. Barros-Silva ◽  
Yashashwi Sinha ◽  
Tariq Ismail ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Head And Neck ◽  
Cancer Cells ◽  
Mtor Inhibitors ◽  
Mtor Pathway ◽  
Current Evidence ◽  
Mtor Inhibition ◽  
Ample Evidence

Radiotherapy is routinely used as a neoadjuvant, adjuvant or palliative treatment in various cancers. There is significant variation in clinical response to radiotherapy with or without traditional chemotherapy. Patients with a good response to radiotherapy demonstrate better clinical outcomes universally across different cancers. The PI3K/AKT/mTOR pathway upregulation has been linked to radiotherapy resistance. We reviewed the current literature exploring the role of inhibiting targets along this pathway, in enhancing radiotherapy response. We identified several studies using in vitro cancer cell lines, in vivo tumour xenografts and a few Phase I/II clinical trials. Most of the current evidence in this area comes from glioblastoma multiforme, non-small cell lung cancer, head and neck cancer, colorectal cancer, and prostate cancer. The biological basis for radiosensitivity following pathway inhibition was through inhibited DNA double strand break repair, inhibited cell proliferation, enhanced apoptosis and autophagy as well as tumour microenvironment changes. Dual PI3K/mTOR inhibition consistently demonstrated radiosensitisation of all types of cancer cells. Single pathway component inhibitors and other inhibitor combinations yielded variable outcomes especially within early clinical trials. There is ample evidence from preclinical studies to suggest that direct pharmacological inhibition of the PI3K/AKT/mTOR pathway components can radiosensitise different types of cancer cells. We recommend that future in vitro and in vivo research in this field should focus on dual PI3K/mTOR inhibitors. Early clinical trials are needed to assess the feasibility and efficacy of these dual inhibitors in combination with radiotherapy in brain, lung, head and neck, breast, prostate and rectal cancer patients.

scholarly journals Characteristics and Treatment Challenges of Non-Clear Cell Renal Cell Carcinoma

Cancers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 3807
Author(s):  
Pierangela Sepe ◽  
Arianna Ottini ◽  
Chiara Carlotta Pircher ◽  
Andrea Franza ◽  
Melanie Claps ◽  
...  
Keyword(s):  
Renal Cell ◽  
Kinase Inhibitors ◽  
Clear Cell ◽  
Case Reports ◽  
Treatment Options ◽  
Single Agent ◽  
Growth Factor Receptor ◽  
Mtor Inhibitors ◽  
Cell Renal Cell Carcinoma ◽  
Clear Cell Rcc

Non-clear cell renal cell carcinomas (RCC) comprise several rare and poorly described diseases, often characterized by bad prognosis and with no standard treatments available. The gap in their clinical management is linked to the poor molecular characterization in handling the treatment of non clear-cell RCC with untailored therapies. Due to their rarity, non-clear RCC are in fact under-represented in prospective randomized trials. Thus, treatment choices are based on extrapolating results from clear cell RCC trials, retrospective data, or case reports. Over the last two decades, various options have been considered as the mainstay for the treatment of metastatic RCC (mRCC), including angiogenesis inhibitors, vascular endothelial growth factor receptor inhibitors, other tyrosine kinase inhibitors (TKIs), as well as MET inhibitors and mammalian targeting of rapamycin (mTOR) inhibitors. More recently, the therapeutic armamentarium has been enriched with immunotherapy, alone or in combination with targeted agents that have been shown to significantly improve outcomes of mRCC patients, if compared to TKI single-agent. It has been widely proven that non-clear cell RCC is a morphologically and clinically distinct entity from its clear cell counterpart but more knowledge about its biology is certainly needed. Histology-specific collaborative trials are in fact now emerging to investigate different treatments for non-clear cell RCC. This review summarizes pathogenetic mechanisms of non-clear cell RCC, the evolution of treatment paradigms over the last few decades, with a focus on immunotherapy-based trials, and future potential treatment options.

scholarly journals Therapeutic clinical trials to combat COVID-19 pandemic in India: analysis from trial registry

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Angelika Batta ◽  
Raj Khirasaria ◽  
Vinod Kapoor ◽  
Deepansh Varshney
Keyword(s):  
Clinical Trials ◽  
De Novo ◽  
Treatment Options ◽  
Drug Repurposing ◽  
Trial Registry ◽  
Therapeutic Treatment ◽  
Clinical Trial Registry ◽  
Clear Cut ◽  
Therapeutic Trials ◽  
Microsoft Office

AbstractObjectivesWith the emergence of Novel corona virus, hunt for finding a preventive and therapeutic treatment options has already begun at a rapid pace with faster clinical development programs. The present study was carried out to give an insight of therapeutic interventional trials registered under clinical trial registry of India (CTRI) for COVID-19 pandemic.MethodsAll trials registered under CTRI were evaluated using keyword “COVID” from its inception till 9th June 2020. Out of which, therapeutic interventional studies were chosen for further analysis. Following information was collected for each trial: type of therapeutic intervention (preventive/therapeutic), treatment given, no. of centers (single center/multicentric), type of institution (government/private), study design (randomized/single-blinded/double-blinded) and sponsors (Government/private). Microsoft Office Excel 2007 was used for tabulation and analysis.ResultsThe search yielded total of 205 trials, out of which, 127 (62%) trials were interventional trials. Out of these, 71 (56%) were AYUSH interventions, 36 (28.3%) tested drugs, 9 (7%) tested a nondrug intervention, rest were nutraceuticals and vaccines. About 66 (56%) were therapeutic trials. Majority were single-centered trials, i.e. 87 (73.7%). Trials were government funded in 57 (48.3%) studies. Majority were randomized controlled trials, i.e. 67 (56.8%). AYUSH preparations included AYUSH-64, Arsenic Album, SamshamaniVati etc.ConclusionsThe number of therapeutic interventional clinical trials was fair in India. A clear-cut need exists for an increase in both quantity and quality of clinical trials for COVID-19. Drug repurposing approach in all systems of medicine can facilitate prompt clinical decisions at lower costs than de novo drug development.

scholarly journals Variation in treatment preferences of pulmonary exacerbations among Australian and New Zealand cystic fibrosis physicians

2021 ◽  
Vol 8 (1) ◽  
pp. e000956
Author(s):  
Grace Currie ◽  
Anna Tai ◽  
Tom Snelling ◽  
André Schultz
Keyword(s):  
Cystic Fibrosis ◽  
Clinical Trials ◽  
New Zealand ◽  
Treatment Options ◽  
Early Response ◽  
Treatment Preferences ◽  
Dornase Alfa ◽  
Clinical Scenarios ◽  
Professional Opinion ◽  
Pulmonary Exacerbations

BackgroundDespite advances in cystic fibrosis (CF) management and survival, the optimal treatment of pulmonary exacerbations remains unclear. Understanding the variability in treatment approaches among physicians might help prioritise clinical uncertainties to address through clinical trials.MethodsPhysicians from Australia and New Zealand who care for people with CF were invited to participate in a web survey of treatment preferences for CF pulmonary exacerbations. Six typical clinical scenarios were presented; three to paediatric and another three to adult physicians. For each scenario, physicians were asked to choose treatment options and provide reasons for their choices.ResultsForty-nine CF physicians (31 paediatric and 18 adult medicine) participated; more than half reported 10+ years of experience. There was considerable variation in primary antibiotic selection; none was preferred by more than half of respondents in any scenario. For secondary antibiotic therapy, respondents consistently preferred intravenous tobramycin and a third antibiotic was rarely prescribed, except in one scenario describing an adult patient. Hypertonic saline nebulisation and twice daily chest physiotherapy was preferred in most scenarios while dornase alfa use was more variable. Most CF physicians (>80%) preferred to change therapy if there was no early response. Professional opinion was the most common reason for antibiotic choice.ConclusionsVariation exists among CF physicians in their preferred choice of primary antibiotic and use of dornase alfa. These preferences are driven by professional opinion, possibly reflecting a lack of evidence to base policy recommendations. Evidence from high-quality clinical trials is needed to inform physician decision making.

scholarly journals Co-Clinical Trials: An Innovative Drug Development Platform for Cholangiocarcinoma

2021 ◽  
Vol 14 (1) ◽  
pp. 51
Author(s):  
Brinda Balasubramanian ◽  
Simran Venkatraman ◽  
Kyaw Zwar Myint ◽  
Tavan Janvilisri ◽  
Kanokpan Wongprasert ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Targeted Therapy ◽  
Drug Development ◽  
Surgical Resection ◽  
Treatment Options ◽  
Standard Of Care ◽  
Time Data ◽  
Current Standard ◽  
Innovative Drug ◽  
Curative Intent

Cholangiocarcinoma (CCA), a group of malignancies that originate from the biliary tract, is associated with a high mortality rate and a concerning increase in worldwide incidence. In Thailand, where the incidence of CCA is the highest, the socioeconomic burden is severe. Yet, treatment options are limited, with surgical resection being the only form of treatment with curative intent. The current standard-of-care remains adjuvant and palliative chemotherapy which is ineffective in most patients. The overall survival rate is dismal, even after surgical resection and the tumor heterogeneity further complicates treatment. Together, this makes CCA a significant burden in Southeast Asia. For effective management of CCA, treatment must be tailored to each patient, individually, for which an assortment of targeted therapies must be available. Despite the increasing numbers of clinical studies in CCA, targeted therapy drugs rarely get approved for clinical use. In this review, we discuss the shortcomings of the conventional clinical trial process and propose the implementation of a novel concept, co-clinical trials to expedite drug development for CCA patients. In co-clinical trials, the preclinical studies and clinical trials are conducted simultaneously, thus enabling real-time data integration to accurately stratify and customize treatment for patients, individually. Hence, co-clinical trials are expected to improve the outcomes of clinical trials and consequently, encourage the approval of targeted therapy drugs. The increased availability of targeted therapy drugs for treatment is expected to facilitate the application of precision medicine in CCA.

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