Repurposing old drugs as new inhibitors of the ubiquitin-proteasome pathway for cancer treatment.

Traditional cancer treatments may lose efficacy following the emergence of novel mutations or the development of chemoradiotherapy resistance. Late diagnosis, high-cost of treatment, and the requirement of highly efficient infrastructure to dispense cancer therapies hinder the availability of adequate treatment in low-income and resource-limited settings. Repositioning approved drugs as cancer therapeutics may reduce the cost and timeline for novel drug development and expedite the availability of newer, efficacious options for patients in need. Nelfinavir is a human immunodeficiency virus (HIV) protease inhibitor that has been approved and is extensively used as an anti-infective agent to treat acquired immunodeficiency syndrome (AIDS). Yet nelfinavir has also shown anti-cancer effects in in vitro and in vivo studies. The anti-cancer mechanism of nelfinavir includes modulation of different cellular conditions, such as unfolded protein response, cell cycle, apoptosis, autophagy, the proteasome pathway, oxidative stress, the tumor microenvironment, and multidrug efflux pumps. Multiple clinical trials indicated tolerable and reversible toxicities during nelfinavir treatment in cancer patients, either as a monotherapy or in combination with chemo- or radiotherapy. Since orally available nelfinavir has been a safe drug of choice for both adult and pediatric HIV-infected patients for over two decades, exploiting its anti-cancer off-target effects will enable fast-tracking this newer option into the existing repertoire of cancer chemotherapeutics.

https://www.mdpi.com/2072-6694/12/11/3437/pdf

The Anti-Cancer Properties of the HIV Protease Inhibitor Nelfinavir.

Small-molecule drug repurposing to target DNA damage repair and response pathways

Nelfinavir (NFV), a FDA approved antiretroviral drug, has been reported to exhibit cancer cells growth inhibition and increased apoptosis. However, it requires a higher dose leading to toxicity, thus limiting its potential clinical translation. We aim to develop biodegradable (poly (lactic-co-glycolic acid)) PLGA nanoparticles of nelfinavir and determine their efficacy to treat non-small cell lung cancer (NSCLC). HIV protease inhibitor, NFV, was loaded into PLGA nanoparticles by double emulsion/solvent evaporation method; and nanoparticles were characterized for physicochemical characteristics including morphology and intracellular uptake. Their anti-cancer efficacy in NSCLC was assessed by in vitro assays including cytotoxicity, cellular migration, colony formation; and 3D spheroid culture mimicking in-vivo tumor microenvironment. Studies were also conducted to elucidate effects on molecular pathways including apoptosis, autophagy, and endoplasmic stress. NFV loaded PLGA nanoparticles (NPs) were found to have particle size: 191.1 ± 10.0 nm, zeta potential: −24.3 ± 0.9 mV, % drug loading: 2.5 ± 0.0%; and entrapment efficiency (EE): 30.1 ± 0.5%. NFV NP inhibited proliferation of NSCLC cells compared to NFV and exhibited significant IC50 reduction. From the caspase-dependent apoptosis assays and western blot studies (upregulation of ATF3), it was revealed that NFV NP significantly induced ER stress marker ATF3, cleaved PARP and further caused autophagy inhibition (LC3BII upregulation) leading to increased cellular death. In addition, NFV NP were found to be more efficacious in penetrating solid tumors in ex-vivo studies compared to plain NFV. Nelfinavir, a lead HIV protease inhibitor can be repositioned as a NSCLC therapeutic through nanoparticulate delivery. Given its ability to induce apoptosis and efficient tumor penetration capability, NFV loaded PLGA nanoparticulate systems provide a promising delivery system in NSCLC treatment.

Nanotechnology Based Repositioning of an Anti-Viral Drug for Non-Small Cell Lung Cancer (NSCLC)

Therapeutic strategies combining radiation therapy with novel agents have become an area of intense research focus in oncology and are actively being investigated for a wide range of solid tumors. The mechanism of action of these systemic agents can be stratified into three general categories: (1) enhancement or alteration of the immune system; (2) disruption of DNA damage response mechanisms; and (3) impediment of cellular signaling pathways involving growth, angiogenesis, and hypoxia. Pre-clinical data suggest that radiation therapy has immunogenic qualities and may optimize response to immuno-oncology therapies by priming the immune system, whereas other novel systemic agents can enhance radiosensitivity through augmentation of genomic instability and alteration of central signaling pathways related to growth and survival. Gynecologic cancers in particular have the potential for synergistic response to combination approaches incorporating radiation therapy and novel systemic therapies. Several clinical trials have been proposed to elucidate the efficacy and safety of such approaches. Here we discuss the mechanisms of novel therapies and the rationale for these combination strategies, reviewing the relevant pre-clinical and clinical data. We explore their optimal use with respect to indications, interactions, and potential synergy in combination with radiation therapy and review ongoing trials and active areas of investigation.

https://ijgc.bmj.com/content/ijgc/30/4/409.full.pdf

Combining novel agents with radiotherapy for gynecologic malignancies: beyond the era of cisplatin

Importance Local failure after chemoradiotherapy (CT-RT) significantly contributes to mortality in patients with locally advanced non–small cell lung cancer (LA-NSCLC). One approach to improve local control is through targeted radiosensitization of the tumor. Objective To evaluate the dose-limiting toxic effects, maximally tolerated dose, and recommended phase 2 dose of the protease inhibitor nelfinavir mesylate, administered concurrently with CT-RT in patients with LA-NSCLC, and, in the phase 2 portion of the study, to estimate the objective response rate, local and distant failure rates, and overall survival. Design, Setting, and Participants This prospective, open-label, single-group, single-institution phase 1/2 trial tested the oral protease inhibitor nelfinavir in combination with concurrent CT-RT in 35 patients aged 18 to 89 years with biopsy-confirmed unresectable stage IIIA/IIIB LA-NSCLC and a minimum Karnofsky performance status from June 29, 2007, to February 22, 2012, with an analysis date of May 9, 2017. Median follow-up for all patients was 6.8 years, with a minimum 5 years of follow-up for all survivors. Interventions Oral nelfinavir mesylate, 625 mg, twice daily or 1250 mg, twice daily was administered for 7 to 14 days before and during concurrent CT-RT. Main Outcomes and Measures Graded toxic effects, overall survival, local failure, distant failure, objective response rate, and progression-free survival as measured by Response Evaluation Criteria in Solid Tumors, version 1.1. Results Thirty-five patients (16 women and 19 men; median age, 60 years [range, 39-79 years]) enrolled and met protocol-specified criteria for adherence, with 5 at a dose of 625 mg twice daily and 30 at a dose of 1250 mg twice daily. No dose-limiting toxic effects were observed. No grade 4 or higher nonhematologic toxic effects were observed. Thirty-three of the 35 patients had evaluable posttreatment computed tomographic scans, with an objective response rate of 94% (31 of 33; 95% CI, 86%-100%). The cumulative incidence of local failure was 39% (95% CI, 30.5%-47.5%). Median progression-free survival was 11.7 months (95% CI, 6.2-17.1 months). Median overall survival for all patients was 41.1 months (95% CI, 19.0-63.1 months); the 5-year mean (SE) overall survival rate was 37.1% (8.2%). Conclusions and Relevance This study suggests that nelfinavir administered with concurrent CT-RT is associated with acceptable toxic effects and a promising objective response rate, local failure, progression-free survival, and overall survival in unresectable LA-NSCLC. These data suggest that nelfinavir may enhance the efficacy of standard CT-RT in this disease. Additional testing in the randomized phase 3 setting should be conducted to establish the improvement associated with nelfinavir with concurrent CT-RT. Trial Registration ClinicalTrials.gov identifier:NCT00589056

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Clinical Outcomes of the HIV Protease Inhibitor Nelfinavir With Concurrent Chemoradiotherapy for Unresectable Stage IIIA/IIIB Non–Small Cell Lung Cancer: A Phase 1/2 Trial

Corey J. Langer

Papers

Clinical Outcomes of the HIV Protease Inhibitor Nelfinavir With Concurrent Chemoradiotherapy for Unresectable Stage IIIA/IIIB Non–Small Cell Lung Cancer: A Phase 1/2 Trial