Macroautophagy (autophagy) is a lysosomal degradation pathway for the breakdown of intracellular proteins and organelles.
Although constitutive autophagy is a homeostatic mechanism for intracellular ...recycling and metabolic regulation, autophagy
is also stress responsive, in which it is important for the removal of damaged proteins and organelles. Autophagy thereby
confers stress tolerance, limits damage, and sustains viability under adverse conditions. Autophagy is a tumor-suppression
mechanism, yet it enables tumor cell survival in stress. Reconciling how loss of a prosurvival function can promote tumorigenesis,
emerging evidence suggests that preservation of cellular fitness by autophagy may be key to tumor suppression. As autophagy
is such a fundamental process, establishing how the functional status of autophagy influences tumorigenesis and treatment
response is important. This is especially critical as many current cancer therapeutics activate autophagy. Therefore, efforts
to understand and modulate the autophagy pathway will provide new approaches to cancer therapy and prevention. (Clin Cancer
Res 2009;15(17):5308â16)
Rapid repurposing of drugs for COVID-19 Guy, R Kiplin; DiPaola, Robert S; Romanelli, Frank ...
Science (American Association for the Advancement of Science),
05/2020, Letnik:
368, Številka:
6493
Journal Article
Recenzirano
Odprti dostop
The emergence of a new coronaviral respiratory disease calls for repurposing existing drugs
In late fall 2019, a novel acute respiratory disease, called coronavirus disease 2019 (COVID-19) emerged in ...Wuhan, China. COVID-19 is caused by severe acute respiratory syndrome–coronavirus 2 (SARS-CoV-2) (
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,
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). COVID-19 has been declared a pandemic by the World Health Organization and continues to spread across the globe. Most patients recover within 1 to 3 weeks. However, a small proportion (∼5%) develop severe illness that can progress to acute respiratory distress syndrome (ARDS), which can lead to death. Currently, only supportive care is available; patients would greatly benefit from the availability of direct therapeutic approaches. One approach to identifying therapeutics is to repurpose approved drugs developed for other uses, which takes advantage of existing detailed information on human pharmacology and toxicology to enable rapid clinical trials and regulatory review.
In this trial, the addition of six cycles of docetaxel to androgen-deprivation therapy resulted in longer median progression-free and overall survival than that with ADT alone in patients with ...metastatic prostate cancer.
Regressions of metastatic prostate cancer were first documented in the 1940s and were achieved with surgical castration; subsequently, androgen-deprivation therapy (ADT) became the mainstay of therapy.
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Attempts to improve the efficacy or decrease the treatment burden of ADT have included the use of antiandrogens alone, intermittent dosing of ADT, and the use of an antiandrogen combined with medical or surgical castration.
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–
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A meta-analysis revealed an increase in survival of 3 percentage points at 5 years with concurrent use of a nonsteroidal antiandrogen at the time of initiation of ADT.
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However, resistance to ADT occurs in most patients, with the . . .
Purpose Docetaxel added to androgen-deprivation therapy (ADT) significantly increases the longevity of some patients with metastatic hormone-sensitive prostate cancer. Herein, we present the outcomes ...of the CHAARTED (Chemohormonal Therapy Versus Androgen Ablation Randomized Trial for Extensive Disease in Prostate Cancer) trial with more mature follow-up and focus on tumor volume. Patients and Methods In this phase III study, 790 patients with metastatic hormone-sensitive prostate cancer were equally randomly assigned to receive either ADT in combination with docetaxel 75 mg/m
for up to six cycles or ADT alone. The primary end point of the study was overall survival (OS). Additional analyses of the prospectively defined low- and high-volume disease subgroups were performed. High-volume disease was defined as presence of visceral metastases and/or ≥ four bone metastases with at least one outside of the vertebral column and pelvis. Results At a median follow-up of 53.7 months, the median OS was 57.6 months for the chemohormonal therapy arm versus 47.2 months for ADT alone (hazard ratio HR, 0.72; 95% CI, 0.59 to 0.89; P = .0018). For patients with high-volume disease (n = 513), the median OS was 51.2 months with chemohormonal therapy versus 34.4 months with ADT alone (HR, 0.63; 95% CI, 0.50 to 0.79; P < .001). For those with low-volume disease (n = 277), no OS benefit was observed (HR, 1.04; 95% CI, 0.70 to 1.55; P = .86). Conclusion The clinical benefit from chemohormonal therapy in prolonging OS was confirmed for patients with high-volume disease; however, for patients with low-volume disease, no OS benefit was discerned.
Macroautophagy (autophagy hereafter) degrades and recycles proteins and organelles to support metabolism and survival in starvation. Oncogenic Ras up-regulates autophagy, and Ras-transformed cell ...lines require autophagy for mitochondrial function, stress survival, and engrafted tumor growth. Here, the essential autophagy gene autophagy-related-7 (atg7) was deleted concurrently with K-ras(G12D) activation in mouse models for non-small-cell lung cancer (NSCLC). atg7-deficient tumors accumulated dysfunctional mitochondria and prematurely induced p53 and proliferative arrest, which reduced tumor burden that was partly relieved by p53 deletion. atg7 loss altered tumor fate from adenomas and carcinomas to oncocytomas-rare, predominantly benign tumors characterized by the accumulation of defective mitochondria. Surprisingly, lipid accumulation occurred in atg7-deficient tumors only when p53 was deleted. atg7- and p53-deficient tumor-derived cell lines (TDCLs) had compromised starvation survival and formed lipidic cysts instead of tumors, suggesting defective utilization of lipid stores. atg7 deficiency reduced fatty acid oxidation (FAO) and increased sensitivity to FAO inhibition, indicating that with p53 loss, Ras-driven tumors require autophagy for mitochondrial function and lipid catabolism. Thus, autophagy is required for carcinoma fate, and autophagy defects may be a molecular basis for the occurrence of oncocytomas. Moreover, cancers require autophagy for distinct roles in metabolism that are oncogene- and tumor suppressor gene-specific.
Summary Background Renal-cell carcinoma is highly vascular, and proliferates primarily through dysregulation of the vascular endothelial growth factor (VEGF) pathway. We tested sunitinib and ...sorafenib, two oral anti-angiogenic agents that are effective in advanced renal-cell carcinoma, in patients with resected local disease at high risk for recurrence. Methods In this double-blind, placebo-controlled, randomised, phase 3 trial, we enrolled patients at 226 study centres in the USA and Canada. Eligible patients had pathological stage high-grade T1b or greater with completely resected non-metastatic renal-cell carcinoma and adequate cardiac, renal, and hepatic function. Patients were stratified by recurrence risk, histology, Eastern Cooperative Oncology Group (ECOG) performance status, and surgical approach, and computerised double-blind randomisation was done centrally with permuted blocks. Patients were randomly assigned (1:1:1) to receive 54 weeks of sunitinib 50 mg per day orally throughout the first 4 weeks of each 6 week cycle, sorafenib 400 mg twice per day orally throughout each cycle, or placebo. Placebo could be sunitinib placebo given continuously for 4 weeks of every 6 week cycle or sorafenib placebo given twice per day throughout the study. The primary objective was to compare disease-free survival between each experimental group and placebo in the intention-to-treat population. All treated patients with at least one follow-up assessment were included in the safety analysis. This trial is registered with ClinicalTrials.gov , number NCT00326898. Findings Between April 24, 2006, and Sept 1, 2010, 1943 patients from the National Clinical Trials Network were randomly assigned to sunitinib (n=647), sorafenib (n=649), or placebo (n=647). Following high rates of toxicity-related discontinuation after 1323 patients had enrolled (treatment discontinued by 193 44% of 438 patients on sunitinib, 199 45% of 441 patients on sorafenib), the starting dose of each drug was reduced and then individually titrated up to the original full doses. On Oct 16, 2014, because of low conditional power for the primary endpoint, the ECOG-ACRIN Data Safety Monitoring Committee recommended that blinded follow-up cease and the results be released. The primary analysis showed no significant differences in disease-free survival. Median disease-free survival was 5·8 years (IQR 1·6–8·2) for sunitinib (hazard ratio HR 1·02, 97·5% CI 0·85–1·23, p=0·8038), 6·1 years (IQR 1·7–not estimable NE) for sorafenib (HR 0·97, 97·5% CI 0·80–1·17, p=0·7184), and 6·6 years (IQR 1·5–NE) for placebo. The most common grade 3 or worse adverse events were hypertension (105 17% patients on sunitinib and 102 16% patients on sorafenib), hand-foot syndrome (94 15% patients on sunitinib and 208 33% patients on sorafenib), rash (15 2% patients on sunitinib and 95 15% patients on sorafenib), and fatigue (110 17% patients on sunitinib and 44 7% patients on sorafenib). There were five deaths related to treatment or occurring within 30 days of the end of treatment; one patient receiving sorafenib died from infectious colitis while on treatment and four patients receiving sunitinib died, with one death due to each of neurological sequelae, sequelae of gastric perforation, pulmonary embolus, and disease progression. Revised dosing still resulted in high toxicity. Interpretation Adjuvant treatment with the VEGF receptor tyrosine kinase inhibitors sorafenib or sunitinib showed no survival benefit relative to placebo in a definitive phase 3 study. Furthermore, substantial treatment discontinuation occurred because of excessive toxicity, despite dose reductions. These results provide a strong rationale against the use of these drugs for high-risk kidney cancer in the adjuvant setting and suggest that the biology of cancer recurrence might be independent of angiogenesis. Funding US National Cancer Institute and ECOG-ACRIN Cancer Research Group, Pfizer, and Bayer.
Antibodies that target the immune checkpoint receptor programmed cell death protein 1 (PD-1) have resulted in prolonged and beneficial responses toward a variety of human cancers. However, anti-PD-1 ...therapy in some patients provides no benefit and/or results in adverse side effects. The factors that determine whether patients will be drug sensitive or resistant are not fully understood; therefore, genomic assessment of exceptional responders can provide important insight into patient response. Here, we identified a patient with endometrial cancer who had an exceptional response to the anti-PD-1 antibody pembrolizumab. Clinical grade targeted genomic profiling of a pretreatment tumor sample from this individual identified a mutation in DNA polymerase epsilon (POLE) that associated with an ultramutator phenotype. Analysis of The Cancer Genome Atlas (TCGA) revealed that the presence of POLE mutation associates with high mutational burden and elevated expression of several immune checkpoint genes. Together, these data suggest that cancers harboring POLE mutations are good candidates for immune checkpoint inhibitor therapy.
Autophagy is a catabolic pathway used by cells to support metabolism in response to starvation and to clear damaged proteins and organelles in response to stress. We report here that expression of a ...H-ras(V12) or K-ras(V12) oncogene up-regulates basal autophagy, which is required for tumor cell survival in starvation and in tumorigenesis. In Ras-expressing cells, defective autophagosome formation or cargo delivery causes accumulation of abnormal mitochondria and reduced oxygen consumption. Autophagy defects also lead to tricarboxylic acid (TCA) cycle metabolite and energy depletion in starvation. As mitochondria sustain viability of Ras-expressing cells in starvation, autophagy is required to maintain the pool of functional mitochondria necessary to support growth of Ras-driven tumors. Human cancer cell lines bearing activating mutations in Ras commonly have high levels of basal autophagy, and, in a subset of these, down-regulating the expression of essential autophagy proteins impaired cell growth. As cancers with Ras mutations have a poor prognosis, this "autophagy addiction" suggests that targeting autophagy and mitochondrial metabolism are valuable new approaches to treat these aggressive cancers.
During tumorigenesis, normal growth mechanisms are deregulated and safeguards that eliminate abnormal cells by apoptosis are disabled. Tumor cells must also increase nutrient uptake and angiogenesis ...to support the upregulation of metabolism necessary for unrestricted growth. In addition, they have to rely on inefficient energy production by glycolysis. This glycolytic state can result from mutations that promote cell proliferation, the hypoxic tumor microenvironment and perhaps mitochondrial malfunction. Moreover, the very signals that enable unrestricted cell proliferation inhibit autophagy, which normally sustains cells during nutrient limitation. In tumors, inactivation of the autophagy pathway may enhance necrosis and inflammation and promote genomic instability, which can further enhance tumor growth. Thus, tumor cells cannot adapt efficiently to metabolic stress and could be induced to die by metabolic catastrophe, in which high energy demand is contrasted by insufficient energy production. Efforts to exploit this unique metabolic state clinically previously focused mainly on detecting tissue displaying increased glycolytic metabolism. The challenge now is to induce metabolic catastrophe therapeutically as an approach to killing the unkillable cells.
Autophagy is an evolutionarily conserved, intracellular self-defense mechanism in which organelles and proteins are sequestered into autophagic vesicles that are subsequently degraded through fusion ...with lysosomes. Cells, thereby, prevent the toxic accumulation of damaged or unnecessary components, but also recycle these components to sustain metabolic homoeostasis. Heightened autophagy is a mechanism of resistance for cancer cells faced with metabolic and therapeutic stress, revealing opportunities for exploitation as a therapeutic target in cancer. We summarize recent developments in the field of autophagy and cancer and build upon the results presented at the Cancer Therapy Evaluation Program (CTEP) Early Drug Development meeting in March 2010. Herein, we describe our current understanding of the core components of the autophagy machinery and the functional relevance of autophagy within the tumor microenvironment, and we outline how this knowledge has informed preclinical investigations combining the autophagy inhibitor hydroxychloroquine (HCQ) with chemotherapy, targeted therapy, and immunotherapy. Finally, we describe ongoing clinical trials involving HCQ as a first generation autophagy inhibitor, as well as strategies for the development of novel, more potent, and specific inhibitors of autophagy.
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