Phase I trial of the human immunodeficiency virus protease inhibitor nelfinavir and chemoradiation for locally advanced pancreatic cancer

Conformational diversity and protein-protein interfaces in drug repurposing in Ras signaling pathway

We focus on drug repurposing in the Ras signaling pathway, considering structural similarities of protein-protein interfaces. The interfaces formed by physically interacting proteins are found from PDB if available and via PRISM (PRotein Interaction by Structural Matching) otherwise. The structural coverage of these interactions has been increased from 21 to 92% using PRISM. Multiple conformations of each protein are used to include protein dynamics and diversity. Next, we find FDA-approved drugs bound to structurally similar protein-protein interfaces. The results suggest that HIV protease inhibitors tipranavir, indinavir, and saquinavir may bind to EGFR and ERBB3/HER3 interface. Tipranavir and indinavir may also bind to EGFR and ERBB2/HER2 interface. Additionally, a drug used in Alzheimer's disease can bind to RAF1 and BRAF interface. Hence, we propose a methodology to find drugs to be potentially used for cancer using a dataset of structurally similar protein-protein interface clusters rather than pockets in a systematic way.

Role of autophagy in tumor response to radiation: Implications for improving radiotherapy

Autophagy is an evolutionary conserved, lysosome-involved cellular process that facilitates the recycling of damaged macromolecules, cellular structures, and organelles, thereby generating precursors for macromolecular biosynthesis through the salvage pathway. It plays an important role in mediating biological responses toward various stress, including those caused by ionizing radiation at the cellular, tissue, and systemic levels thereby implying an instrumental role in shaping the tumor responses to radiotherapy. While a successful execution of autophagy appears to facilitate cell survival, abortive or interruptions in the completion of autophagy drive cell death in a context-dependent manner. Pre-clinical studies establishing its ubiquitous role in cells and tissues, and the systemic response to focal irradiation of tumors have prompted the initiation of clinical trials using pharmacologic modifiers of autophagy for enhancing the efficacy of radiotherapy. However, the outcome from the Phase I/II trials in many human malignancies has so far been equivocal. Such observations have not only precluded the advancement of these autophagy modifiers in the Phase III trial but have also raised concerns regarding their introduction as an adjuvant to radiotherapy. This warrants a thorough understanding of the biology of the cancer cells, including its spatio-temporal context, as well as its microenvironment all of which might be the crucial factors that determine the success of an autophagy modifier as an anticancer agent. This review captures the current understanding of the interplay between radiation induced autophagy and the biological responses to radiation damage as well as provides insight into the potentials and limitations of targeting autophagy for improving the radiotherapy of tumors.

Interactions between HIV protease inhibitor ritonavir and human DNA repair enzyme ALKBH2: a molecular dynamics simulation study

The human DNA repair enzyme AlkB homologue-2 (ALKBH2) repairs methyl adducts from genomic DNA. Overexpression of ALKBH2 has been implicated in both tumorigenesis and chemotherapy resistance in some cancers, including glioblastoma and renal cancer rendering it a potential therapeutic target and a diagnostic marker. However, no inhibitor is available against these important DNA repair proteins. Intending to repurpose a drug as an inhibitor of ALKBH2, we performed in silico evaluation of HIV protease inhibitors and identified Ritonavir as an ALKBH2-interacting molecule. Using molecular dynamics simulation, we elucidated the molecular details of Ritonavir-ALKBH2 interaction. The present work highlights that Ritonavir might be used to target the ALKBH2-mediated DNA alkylation repair.

Concurrent chemoradiation and brachytherapy alone or in combination with nelfinavir in locally advanced cervical cancer (NELCER): study protocol for a phase III trial

INTRODUCTION

In locally advanced cervical cancer, nodal, local and distant relapse continue to be significant patterns of relapse. Therefore, strategies to improve the efficacy of chemoradiation are desirable such as biological pathway modifiers and immunomodulating agents. This trial will investigate the impact of nelfinavir, a protease inhibitor that targets the protein kinase B (AKT) pathway on disease-free survival (DFS).

METHODS AND ANALYSIS

Radiosensitising effect of nelfinavir in locally advanced carcinoma of cervix is a single-centre, open-label, parallel-group, 1:1 randomised phase-III study. Patients aged over 18 years with a diagnosis of carcinoma cervix stage III are eligible for the study. After consenting, patients will undergo randomisation to chemoradiation and brachytherapy arm or nelfinavir with chemoradiation and brachytherapy arm. The primary aim of the study is to compare the difference in 3-year DFS between the two arms. Secondary aims are locoregional control, overall survival, toxicity and quality of life between the two arms. Pharmacokinetics of nelfinavir and its impact on tumour AKT, programmed cell death ligand 1, cluster of differentiation 4, cluster of differentiation 8 and natural killer 1.1 expression will be investigated. The overall sample size of 348 with 1 planned interim analysis achieves 80% power at a 0.05 significance level to detect a HR of 0.66 when the proportion surviving in the control arm is 0.65. The planned study duration is 8 years.

ETHICS AND DISSEMINATION

The trial is approved by the Institutional Ethics Committee-I of Tata Memorial Hospital, Mumbai (reference number: IEC/0317/1543/001) and will be monitored by the data safety monitoring committee. The study results will be disseminated via peer-reviewed scientific journals, and conference presentations. Study participants will be accrued after obtaining written informed consent from them. The confidentiality and privacy of study participants will be maintained.

TRIAL REGISTRATION NUMBER

The trial is registered with Clinical Trials Registry-India (CTRI/2017/08/009265) and ClinicalTrials.gov (NCT03256916).

Drug Repurposing, an Attractive Strategy in Pancreatic Cancer Treatment: Preclinical and Clinical Updates

Pancreatic cancer (PC) is one of the deadliest malignancies worldwide, since patients rarely display symptoms until an advanced and unresectable stage of the disease. Current chemotherapy options are unsatisfactory and there is an urgent need for more effective and less toxic drugs to improve the dismal PC therapy. Repurposing of non-oncology drugs in PC treatment represents a very promising therapeutic option and different compounds are currently being considered as candidates for repurposing in the treatment of this tumor. In this review, we provide an update on some of the most promising FDA-approved, non-oncology, repurposed drug candidates that show prominent clinical and preclinical data in pancreatic cancer. We also focus on proposed mechanisms of action and known molecular targets that they modulate in PC. Furthermore, we provide an explorative bioinformatic analysis, which suggests that some of the PC repurposed drug candidates have additional, unexplored, oncology-relevant targets. Finally, we discuss recent developments regarding the immunomodulatory role displayed by some of these drugs, which may expand their potential application in synergy with approved anticancer immunomodulatory agents that are mostly ineffective as single agents in PC.

The association between protease inhibitors and anal cancer outcomes in veterans living with HIV treated with definitive chemoradiation: a retrospective study

BACKGROUND

The incidence of anal squamous cell carcinoma has been increasing, particularly in people living with HIV (PLWH). There is concern that radiosensitizing drugs, such as protease inhibitors, commonly used in the management of HIV, may increase toxicities in patients undergoing chemoradiation. This study examines treatment outcomes and toxicities in PLWH managed with and without protease inhibitors who are receiving chemoradiation for anal cancer.

METHODS

Patient demographic, HIV management, and cancer treatment information were extracted from multiple Veterans Affairs databases. Patients were also manually chart reviewed. Among PLWH undergoing chemoradiation for anal carcinoma, therapy outcomes and toxicities were compared between those treated with and without protease inhibitors at time of cancer treatment. Statistical analysis was performed using chi-square, Cox regression analysis, and logistic regression.

RESULTS

A total of 219 PLWH taking anti-retroviral therapy undergoing chemoradiation for anal cancer were identified and included in the final analysis. The use of protease inhibitors was not associated with any survival outcome including colostomy-free survival, progression-free survival, or overall survival (all adjusted hazard ratio p-values> 0.05). Regarding toxicity, protease inhibitor use was not associated with an increased odds of hospitalizations or non-hematologic toxicities; however, protease inhibitor use was associated with increased hospitalizations for hematologic toxicities, including febrile neutropenia (p < 0.01).

CONCLUSION

The use of protease inhibitors during chemoradiation for anal carcinoma was not associated with any clinical outcome or increase in non-hematologic toxicity. Their use was associated with increased hospitalizations for hematologic toxicities. Further prospective research is needed to evaluate the safety and efficacy of protease inhibitors for patients undergoing chemoradiation.

Phase 1 trial of nelfinavir added to standard cisplatin chemotherapy with concurrent pelvic radiation for locally advanced cervical cancer

BACKGROUND

Nelfinavir (NFV), an HIV-1 protease inhibitor, has been shown to sensitize cancer cells to chemoradiation (CRT). The objectives of this phase 1 trial were to evaluate safety and identify the recommended phase 2 dose of NFV added to concurrent CRT for locally advanced cervical cancer.

METHODS

Two dose levels of NFV were evaluated: 875 mg orally twice daily (dose level 1 [DL1]) and 1250 mg twice daily (DL2). NFV was initiated 7 days before CRT and continued through CRT completion. Toxicity, radiographic responses, and pathologic responses were evaluated. Serial tumor biopsies (baseline, after NFV monotherapy, on NFV + CRT, and posttreatment) were evaluated by immunohistochemistry, NanoString, and reverse-phase-protein-array analyses.

RESULTS

NFV sensitized cervical cancer cells to radiation, increasing apoptosis and tumor suppression in vivo. Patients (n = 13) with International Federation of Gynecology and Obstetrics stage IIA through IVA squamous cell cervical carcinoma were enrolled, including 7 patients at DL1 and 6 patients at DL2. At DL1, expansion to 6 patients was required after a patient developed a dose-limiting toxicity, whereas no dose-limiting toxicities occurred at DL2. Therefore, DL2 was established as the recommended phase 2 dose. All patients at DL2 completed CRT, and 1 of 6 experienced grade 3 or 4 anemia, nausea, and diarrhea. One recurrence was noted at DL2, with disease outside the radiation field. Ten of 11 evaluable patients remained without evidence of disease at a median follow-up of 50 months. NFV significantly decreased phosphorylated Akt levels in tumors. Cell cycle and cancer pathways also were reduced by NFV and CRT.

CONCLUSIONS

NFV with CRT is well tolerated. The response rate is promising compared with historic controls in this patient population and warrants further investigation.

Drug Repurposing Opportunities in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is considered one of the deadliest tumors worldwide. The diagnosis is often possible only in the latter stages of the disease, with patients already presenting an advanced or metastatic tumor. It is also one of the cancers with poorest prognosis, presenting a five-year survival rate of around 5%. Treatment of PDAC is still a major challenge, with cytotoxic chemotherapy remaining the basis of systemic therapy. However, no major advances have been made recently, and therapeutic options are limited and highly toxic. Thus, novel therapeutic options are urgently needed. Drug repurposing is a strategy for the development of novel treatments using approved or investigational drugs outside the scope of the original clinical indication. Since repurposed drugs have already completed several stages of the drug development process, a broad range of data is already available. Thus, when compared with de novo drug development, drug repurposing is time-efficient, inexpensive and has less risk of failure in future clinical trials. Several repurposing candidates have been investigated in the past years for the treatment of PDAC, as single agents or in combination with conventional chemotherapy. This review gives an overview of the main drugs that have been investigated as repurposing candidates, for the potential treatment of PDAC, in preclinical studies and clinical trials.

The Anti-Cancer Properties of the HIV Protease Inhibitor Nelfinavir

Simple Summary

To this day, cancer remains a medical challenge despite the development of cutting-edge diagnostic methods and therapeutics. Thus, there is a continual demand for improved therapeutic options for managing cancer patients. However, novel drug development requires decade-long time commitment and financial investments. Repurposing approved and market-available drugs for cancer therapy is a way to reduce cost and the timeframe for developing new therapies. Nelfinavir is an anti-infective agent that has extensively been used to treat acquired immunodeficiency syndrome (AIDS) in adult and pediatric patients. In addition to its anti-infective properties, nelfinavir has demonstrated potent off-target anti-cancer effects, suggesting that it could be a suitable candidate for drug repurposing for cancer. In this review, we systematically compiled the therapeutic benefits of nelfinavir against cancer as a single drug or in combination with chemoradiotherapy, and outlined the possible underlying mechanistic pathways contributing to the anti-cancer effects.

Abstract

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.

HIV-1, HAART and cancer: A complex relationship

HIV infected people are at higher risk of developing cancer, although it is globally diminished in the era of highly active antiretroviral treatment (HAART). Recently, antioncogenic properties of some HAART drugs were discovered. We discuss the role of HAART in the prevention and improvement of treatment outcomes of cancers in HIV-infected people. We describe different trends in HAART-cancer relationships: cancer-predisposing as well as cancer-preventing. We cover the roles of particular drug regimens in cancer prevention. We also describe the causes of cancer treatment with HAART drugs in HIV-negative people, including ongoing clinical studies that may directly point to a possible independent anti-oncogenic activity of HAART drugs. We conclude that despite potent antioncogenic activities of every class of HAART drugs reported in preclinical models, the evidence to date indicates that their independent clinical impact in HIV-infected people is limited. Improved cancer prevention strategies besides HAART are needed to reduce HIV-cancer-related mortality.

Drug rechanneling: A novel paradigm for cancer treatment

Cancer continues to be one of the leading contributors towards global disease burden. According to NIH, cancer incidence rate per year will increase to 23.6 million by 2030. Even though cancer continues to be a major proportion of the disease burden worldwide, it has the lowest clinical trial success rate amongst other diseases. Hence, there is an unmet need for novel, affordable and effective anti-neoplastic medications. As a result, a growing interest has sparkled amongst researchers towards drug repurposing. Drug repurposing follows the principle of polypharmacology, which states, "any drug with multiple targets or off targets can present several modes of action". Drug repurposing also known as drug rechanneling, or drug repositioning is an economic and reliable approach that identifies new disease treatment of already approved drugs. Repurposing guarantees expedited access of drugs to the patients as these drugs are already FDA approved and their safety and toxicity profile is completely established. Epidemiological studies have identified the decreased occurrence of oncological or non-oncological conditions in patients undergoing treatment with FDA approved drugs. Data from multiple experimental studies and clinical observations have depicted that several non-neoplastic drugs have potential anticancer activity. In this review, we have summarized the potential anti-cancer effects of anti-psychotic, anti-malarial, anti-viral and anti-emetic drugs with a brief overview on their mechanism and pathways in different cancer types. This review highlights promising evidences for the repurposing of drugs in oncology.

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

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.

Targeting AKT/PKB to improve treatment outcomes for solid tumors

The serine/threonine kinase AKT, also known as protein kinase B (PKB), is the major substrate to phosphoinositide 3-kinase (PI3K) and consists of three paralogs: AKT1 (PKBα), AKT2 (PKBβ) and AKT3 (PKBγ). The PI3K/AKT pathway is normally activated by binding of ligands to membrane-bound receptor tyrosine kinases (RTKs) as well as downstream to G-protein coupled receptors and integrin-linked kinase. Through multiple downstream substrates, activated AKT controls a wide variety of cellular functions including cell proliferation, survival, metabolism, and angiogenesis in both normal and malignant cells. In human cancers, the PI3K/AKT pathway is most frequently hyperactivated due to mutations and/or overexpression of upstream components. Aberrant expression of RTKs, gain of function mutations in PIK3CA, RAS, PDPK1, and AKT itself, as well as loss of function mutation in AKT phosphatases are genetic lesions that confer hyperactivation of AKT. Activated AKT stimulates DNA repair, e.g. double strand break repair after radiotherapy. Likewise, AKT attenuates chemotherapy-induced apoptosis. These observations suggest that a crucial link exists between AKT and DNA damage. Thus, AKT could be a major predictive marker of conventional cancer therapy, molecularly targeted therapy, and immunotherapy for solid tumors. In this review, we summarize the current understanding by which activated AKT mediates resistance to cancer treatment modalities, i.e. radiotherapy, chemotherapy, and RTK targeted therapy. Next, the effect of AKT on response of tumor cells to RTK targeted strategies will be discussed. Finally, we will provide a brief summary on the clinical trials of AKT inhibitors in combination with radiochemotherapy, RTK targeted therapy, and immunotherapy.

Identification of the targeted therapeutic potential of doxycycline for a subset of gastric cancer patients

The identification of new drugs for the targeted therapy of gastric cancer remains an important need. The RAS/RAF/MEK/ERK/ELK1 signaling cascade is activated in many cancers, including gastric cancer. To identify the targetable inhibitors of the ERK/MAPK pathway, we performed a repurposing screening of a panel of antimicrobial agents in gastric cancer cells using an ERK/MAPK-driven firefly luciferase reporter assay. Multiple antibiotics were identified to inhibit ERK-mediated transcriptional activity. Among them, doxycycline showed high inhibition of ERK/MAPK-regulated transcriptional activity and the levels of ERK proteins. Doxycycline was further identified to inhibit the proliferation and the colony- and spheroid-forming potential of gastric cancer cells. By in vitro signaling pathway and genome-wide expression profiling analyses, doxycycline was identified to inhibit signaling pathways and transcriptional activities regulated by ER, Myc, E2F1, Wnt, SMAD2/3/4, Notch, and OCT4. Doxycycline was also found to activate p53-, ATF6-, NRF1/2-, and MTF1-mediated transcription and inhibit the transcription of histones, proteasomal genes, fibroblast growth factor, and other oncogenic factors. These observations show the multitargeting and targeted therapeutic features of doxycycline for a subset of gastric tumors.

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

The ubiquitin-proteasome system (UPS) plays a central role in the degradation of cellular proteins. Targeting protein degradation has been validated as an effective strategy for cancer therapy since 2003. Several components of the UPS have been validated as potential anticancer targets, including 20S proteasomes, 19S proteasome-associated deubiquitinases (DUBs) and ubiquitin ligases (E3s). 20S proteasome inhibitors (such as bortezomib/BTZ and carfilzomib/CFZ) have been approved by the U.S. Food and Drug Administration (FDA) for the treatment of multiple myeloma (MM) and some other liquid tumors. Although survival of MM patients has been improved by the introduction of BTZ-based therapies, these clinical 20S proteasome inhibitors have several limitations, including emergence of resistance in MM patients, neuro-toxicities, and little efficacy in solid tumors. One of strategies to improve the current status of cancer treatment is to repurpose old drugs with UPS-inhibitory properties as new anticancer agents. Old drug reposition represents an attractive drug discovery approach compared to the traditional de novo drug discovery process which is time-consuming and costly. In this review, we summarize status of repurposed inhibitors of various UPS components, including 20S proteasomes, 19S-associated DUBs, and ubiquitin ligase E3s. The original and new mechanisms of action, molecular targets, and potential anticancer activities of these repurposed UPS inhibitors are reviewed, and their new uses including combinational therapies for cancer treatment are discussed.

Lymphocyte-sparing effect of stereotactic body radiation therapy compared to conventional fractionated radiation therapy in patients with locally advanced pancreatic cancer

BACKGROUND

Conventionally fractionated (CF) radiation therapy (RT) has been associated with lymphopenia, leading to compromised overall survival (OS) in cancer patients. It currently remains unknown if stereotactic body (SB) RT induces lymphopenia to the same degree. The aim of this study is to determine if SBRT with either chemotherapy (CMT) (Fluorouracil (5FU) or capecitabine) or Nelfinavir (NFV) to pancreatic adenocarcinoma induces lymphopenia to the same degree as CFRT with 5FU or capecitabine and how any associated difference affects patient survival outcomes.

METHODS

Medical records of pancreatic adenocarcinoma patients treated with induction CMT followed by RT with concurrent CMT or NFV were reviewed. Patients with total lymphocyte counts (TLCs) available both prior to and following initiation of RT were included. Three groups were identified: CFRT/CMT, SBRT/CMT, and SBRT/NFV. Median delivered RT doses for CFRT and SBRT were 50.4 Gy in 1.8 Gy fractions and 35 Gy in 7 Gy fractions, respectively. TLCs from day 0 (the first day of RT) to 40 were recorded and analyzed using the Kruskal-Wallis test with p-values adjusted with Bonferroni's method. Linear regressions were utilized to estimate the slope of TLCs as it changes with time and survival analysis was performed via Kaplan-Meier plots.

RESULTS

One hundred patients were identified (28 CFRT/CMT, 27 SBRT/CMT, 45 SBRT/NFV). Median pre-RT TLCs were not different among groups. Median lowest TLCs were significantly lower (p <  0.0001) and median TLCs reduction over time were significantly greater (p <  0.0001) in the CFRT group than SBRT groups. There was no difference in lowest TLCs or TLCs reduction over time between SBRT groups. Across all groups, the median time to lowest TLCs was similar. Survival analysis revealed no significant difference in median OS between SBRT and CFRT groups. However, in patients with surgery, Median OS for patients with SBRT/CMT was significantly higher than in those with SBRT/NFV (p = 0.03).

CONCLUSIONS

Compared to CFRT, SBRT is associated with less lymphopenia. Further study of the effect of radiation technique on immune status is warranted.

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

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.

Buparlisib with thoracic radiotherapy and its effect on tumour hypoxia: A phase I study in patients with advanced non-small cell lung carcinoma

BACKGROUND

Pre-clinically, phosphoinositide 3-kinase (PI3K) inhibition radiosensitises tumours by increasing intrinsic radiosensitivity and by reducing tumour hypoxia. We assessed whether buparlisib, a class 1 PI3K inhibitor, can be safely combined with radiotherapy in patients with non-small cell lung carcinoma (NSCLC) and investigated its effect on tumour hypoxia.

METHODS

This was a 3 + 3 dose escalation and dose expansion phase I trial in patients with advanced NSCLC. Buparlisib dose levels were 50 mg, 80 mg and 100 mg once daily orally for 2 weeks, with palliative thoracic radiotherapy (20 Gy in 5 fractions) delivered during week 2. Tumour hypoxic volume (HV) was measured using 18F-fluoromisonidazole positron-emission tomography-computed tomography at baseline and following 1 week of buparlisib.

RESULTS

Twenty-one patients were recruited with 9 patients evaluable for maximum tolerated dose (MTD) analysis. No dose-limiting toxicity was reported; therefore, 100 mg was declared the MTD, and 10 patients received this dose in the expansion phase. Ninety-four percent of treatment-related adverse events were ≤grade 2 with fatigue (67%), nausea (24%) and decreased appetite (19%) most common per patient. One serious adverse event (grade 3 hypoalbuminaemia) was possibly related to buparlisib. No unexpected radiotherapy toxicity was reported. Ten (67%) of 15 patients evaluable for imaging analysis were responders with 20% median reduction in HV at the MTD.

CONCLUSION

This is the first clinical trial to combine a PI3K inhibitor with radiotherapy in NSCLC and investigate the effects of PI3K inhibition on tumour hypoxia. This combination was well tolerated and PI3K inhibition reduced hypoxia, warranting investigation into whether this novel class of radiosensitisers can improve radiotherapy outcomes.

Study protocol: a multi-centre randomised study of induction chemotherapy followed by capecitabine ± nelfinavir with high- or standard-dose radiotherapy for locally advanced pancreatic cancer (SCALOP-2)

BACKGROUND

Induction chemotherapy followed by chemoradiation is a treatment option for patients with locally advanced pancreatic cancer (LAPC). However, overall survival is comparable to chemotherapy alone and local progression occurs in nearly half of all patients, suggesting chemoradiation strategies should be optimised. SCALOP-2 is a randomised phase II trial testing the role of radiotherapy dose escalation and/or the addition of the radiosensitiser nelfinavir, following induction chemotherapy of gemcitabine and nab-paclitaxel (GEMABX). A safety run-in phase (stage 1) established the nelfinavir dose to administer with chemoradiation in the randomised phase (stage 2).

METHODS

Patients with locally advanced, inoperable, non-metastatic pancreatic adenocarcinoma receive three cycles of induction GEMABX chemotherapy prior to radiological assessment. Those with stable/responding disease are eligible for further trial treatment. In Stage 1, participants received one further cycle of GEMABX followed by capecitabine-chemoradiation with escalating doses of nelfinavir in a rolling-six design. Stage 2 aims to register 262 and randomise 170 patients with responding/stable disease to one of five arms: capecitabine with high- (arms C + D) or standard-dose (arms A + B) radiotherapy with (arms A + C) or without (arms B + D) nelfinavir, or three more cycles of GEMABX (arm E). Participants allocated to the chemoradiation arms receive another cycle of GEMABX before chemoradiation begins. Co-primary outcomes are 12-month overall survival (radiotherapy dose-escalation question) and progression-free survival (nelfinavir question). Secondary outcomes include toxicity, quality of life, disease response rate, resection rate, treatment compliance, and CA19-9 response. SCALOP-2 incorporates a detailed radiotherapy quality assurance programme.

DISCUSSION

SCALOP-2 aims to optimise chemoradiation in LAPC and incorporates a modern induction regimen.

TRIAL REGISTRATION

Eudract No: 2013-004968-56; ClinicalTrials.gov : NCT02024009.

Targeting DNA Double-Strand Break Repair Pathways to Improve Radiotherapy Response

More than half of cancer patients receive radiotherapy as a part of their cancer treatment. DNA double-strand breaks (DSBs) are considered as the most lethal form of DNA damage and a primary cause of cell death and are induced by ionizing radiation (IR) during radiotherapy. Many malignant cells carry multiple genetic and epigenetic aberrations that may interfere with essential DSB repair pathways. Additionally, exposure to IR induces the activation of a multicomponent signal transduction network known as DNA damage response (DDR). DDR initiates cell cycle checkpoints and induces DSB repair in the nucleus by non-homologous end joining (NHEJ) or homologous recombination (HR). The canonical DSB repair pathways function in both normal and tumor cells. Thus, normal-tissue toxicity may limit the targeting of the components of these two pathways as a therapeutic approach in combination with radiotherapy. The DSB repair pathways are also stimulated through cytoplasmic signaling pathways. These signaling cascades are often upregulated in tumor cells harboring mutations or the overexpression of certain cellular oncogenes, e.g., receptor tyrosine kinases, PIK3CA and RAS. Targeting such cytoplasmic signaling pathways seems to be a more specific approach to blocking DSB repair in tumor cells. In this review, a brief overview of cytoplasmic signaling pathways that have been reported to stimulate DSB repair is provided. The state of the art of targeting these pathways will be discussed. A greater understanding of the underlying signaling pathways involved in DSB repair may provide valuable insights that will help to design new strategies to improve treatment outcomes in combination with radiotherapy.

Phase I trial of concurrent stereotactic body radiotherapy and nelfinavir for locally advanced borderline or unresectable pancreatic adenocarcinoma

INTRODUCTION

The HIV protease inhibitor nelfinavir (NFV) displays notable radiosensitizing effects. There have been no studies evaluating combined stereotactic body radiotherapy (SBRT) and NFV for borderline/unresectable pancreatic cancer. The primary objective of this phase I trial (NCT01068327) was to determine the maximum tolerated SBRT/NFV dose, and secondarily evaluate outcomes.

METHODS

Following initial imaging, pathologic confirmation, and staging laparoscopy, subjects initially received three 3-week cycles of gemcitabine/leucovorin/fluorouracil; patients without radiologic progression received 5-fraction SBRT/NFV. Dose escalation was as follows: (1) 25 Gy/625 mg BID ×3wks; (2) 25 Gy/1250 mg BID ×3wks; (3) 30 Gy/1250 mg BID ×3wks; (4) 35 Gy/1250 mg BID ×3wks; (5) 35 Gy/1250 mg BID ×5wks; and (6) 40 Gy/1250 mg BID ×5wks. Pancreaticoduodenectomy was performed thereafter if resectable; if not, gemcitabine/leucovorin/fluorouracil was administered.

RESULTS

Forty-six patients enrolled (10/2008-5/2013); 39 received protocol-directed therapy. Sixteen (41%) experienced any grade ≥2 event during and 1 month after SBRT. Four grade 3 and both grade 4 events occurred in a single patient at the initial dose level. 40 Gy/1250 mg BID ×5wks was the maximum tolerated dose. Five patients had late gastrointestinal bleeding (n = 2 superior mesenteric artery pseudo-aneurysm, n = 1 disease progression, n = 1 lower GI tract, n = 1 unknown location). The median overall survival was 14.4 months. Six (15%) patients recurred locally; median local failure-free survival was not reached. The median distant failure-free survival was 11 months, and median all failure-free survival was 10 months.

CONCLUSIONS

Concurrent SBRT (40 Gy)/NFV (1250 mg BID) for locally advanced pancreatic cancer is feasible and safe, although careful attention to treatment planning parameters is recommended to reduce the incidence of late gastrointestinal bleeding.

Effects of repurposed drug candidates nitroxoline and nelfinavir as single agents or in combination with erlotinib in pancreatic cancer cells

Background

Pancreatic cancer (PC) is the fourth most common cause of cancer death. Combination therapies with classical chemotherapeutic agents improved treatment of advanced PC at the cost of a relevant toxicity, but the 5-year survival rate remains below 5%. Consequently, new therapeutic options for this disease are urgently needed. In this study, we explored the effect of two repurposed drug candidates nelfinavir and nitroxoline, approved for non-anticancer human use, in PC cell lines. Nelfinavir and nitroxoline were tested as single agents, or in combinations with or without erlotinib, a targeted drug approved for PC treatment.

Methods

The effects of the drugs on the viability of AsPC-1, Capan-2 and BxPC-3 PC cell lines were assessed by MTT. The impact of the treatments on cell cycle distribution and apoptosis was analyzed by flow cytometry. The effects of treatments on proteins relevant in cell cycle regulation and apoptosis were evaluated by western blot. Self-renewal capacity of PC cell lines after drug treatments was assessed using a clonogenic assay.

Results

When used as single agents, nelfinavir and nitroxoline decreased viability, affected cell cycle and reduced the expression of relevant cell cycle proteins. The effects on apoptosis were variable among PC cell lines. Moreover, these agents drastically impaired clonogenic activity of the three PC cell lines. Combinations of nelfinavir and nitroxoline, with or without erlotinib, resulted in dose- and cell-dependent synergistic effects on cell viability. These effects were paralleled by cell cycle alterations and more consistent apoptosis induction as compared to single agents. Treatments with drug combinations induced drastic impairment of clonogenic activity in the three cell lines.

Conclusions

This study shows that two non-antitumor drugs, nelfinavir and nitroxoline, as single agents or in combination have antitumor effects that appear comparable, or in some case more pronounced than those of erlotinib in three PC cell lines. Our results support repurposing of these approved drugs as single agents or in combination for PC treatment.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0904-2) contains supplementary material, which is available to authorized users.

[Radiotherapy for HIV-infected patients]

Since the advent of highly active antiretroviral therapy, cancer incidence is still 2 to 3-fold higher in patients infected by human immunodeficiency virus (HIV) than in the general population, with an increased incidence of malignancies not associated with acquired immunodeficiency syndrome (AIDS). HIV-infected patients cancer treatment does not differ from that in the general population. However, the management of those patients have some particularities due to preexisting comorbid conditions, including metabolic, cardiovascular, renal or hepatic complications and the risk for potential drug - drug interactions in HIV-infected patients. In this review, we described efficacy and tolerance of radiotherapy with or without chemotherapy in this frail population treated for cancer. Utilization of modern radiotherapy techniques such as intensity-modulated radiotherapy may improve the treatment tolerance.

HIV Infection and Survival Among Women With Cervical Cancer

Purpose Cervical cancer is the leading cause of cancer death among the 20 million women with HIV worldwide. We sought to determine whether HIV infection affected survival in women with invasive cervical cancer. Patients and Methods We enrolled sequential patients with cervical cancer in Botswana from 2010 to 2015. Standard treatment included external beam radiation and brachytherapy with concurrent cisplatin chemotherapy. The effect of HIV on survival was estimated by using an inverse probability weighted marginal Cox model. Results A total of 348 women with cervical cancer were enrolled, including 231 (66.4%) with HIV and 96 (27.6%) without HIV. The majority (189 [81.8%]) of women with HIV received antiretroviral therapy before cancer diagnosis. The median CD4 cell count for women with HIV was 397 (interquartile range, 264 to 555). After a median follow-up of 19.7 months, 117 (50.7%) women with HIV and 40 (41.7%) without HIV died. One death was attributed to HIV and the remaining to cancer. Three-year survival for the women with HIV was 35% (95% CI, 27% to 44%) and 48% (95% CI, 35% to 60%) for those without HIV. In an adjusted analysis, HIV infection significantly increased the risk for death among all women (hazard ratio, 1.95; 95% CI, 1.20 to 3.17) and in the subset that received guideline-concordant curative treatment (hazard ratio, 2.63; 95% CI, 1.05 to 6.55). The adverse effect of HIV on survival was greater for women with a more-limited stage cancer ( P = .035), those treated with curative intent ( P = .003), and those with a lower CD4 cell count ( P = .036). Advanced stage and poor treatment completion contributed to high mortality overall. Conclusion In the context of good access to and use of antiretroviral treatment in Botswana, HIV infection significantly decreases cervical cancer survival.

Biological determinants of radioresistance and their remediation in pancreatic cancer

Despite recent advances in radiotherapy, a majority of patients diagnosed with pancreatic cancer (PC) do not achieve objective responses due to the existence of intrinsic and acquired radioresistance. Identification of molecular mechanisms that compromise the efficacy of radiation therapy and targeting these pathways is paramount for improving radiation response in PC patients. In this review, we have summarized molecular mechanisms associated with the radio-resistant phenotype of PC. Briefly, we discuss the reversible and irreversible biological consequences of radiotherapy, such as DNA damage and DNA repair, mechanisms of cancer cell survival and radiation-induced apoptosis following radiotherapy. We further describe various small molecule inhibitors and molecular targeting agents currently being tested in preclinical and clinical studies as potential radiosensitizers for PC. Notably, we draw attention towards the confounding effects of cancer stem cells, immune system, and the tumor microenvironment in the context of PC radioresistance and radiosensitization. Finally, we discuss the need for examining selective radioprotectors in light of the emerging evidence on radiation toxicity to non-target tissue associated with PC radiotherapy.

Targeting the AKT pathway: Repositioning HIV protease inhibitors as radiosensitizers

Cellular resistance in tumour cells to different therapeutic approaches has been a limiting factor in the curative treatment of cancer. Resistance to therapeutic radiation is a common phenomenon which significantly reduces treatment options and impacts survival. One of the mechanisms of acquiring resistance to ionizing radiation is the overexpression or activation of various oncogenes like the EGFR (epidermal growth factor receptor), RAS (rat sarcoma) oncogene or loss of PTEN (phosphatase and tensin homologue) which in turn activates the phosphatidyl inositol 3-kinase/protein kinase B (PI3-K)/AKT pathway responsible for radiation resistance in various tumours. Blocking the pathway enhances the radiation response both in vitro and in vivo. Due to the differential activation of this pathway (constitutively activated in tumour cells and not in the normal host cells), it is an excellent candidate target for molecular targeted therapy to enhance radiation sensitivity. In this regard, HIV protease inhibitors (HPIs) known to interfere with PI3-K/AKT signaling in tumour cells, have been shown to sensitize various tumour cells to radiation both in vitro and in vivo. As a result, HPIs are now being investigated as possible radiosensitizers along with various chemotherapeutic drugs. This review describes the mechanisms by which PI3-K/AKT pathway causes radioresistance and the role of HIV protease inhibitors especially nelfinavir as a potential candidate drug to target the AKT pathway for overcoming radioresistance and its use in various clinical trials for different malignancies.

The HIV protease inhibitor, nelfinavir, as a novel therapeutic approach for the treatment of refractory pediatric leukemia

PURPOSE

Refractory pediatric leukemia remains one of the leading causes of death in children. Intensification of current chemotherapy regimens to improve the outcome in these children is often limited by the effects of drug resistance and cumulative toxicity. Hence, the search for newer agents and novel therapeutic approaches are urgently needed to formulate the next-generation early-phase clinical trials for these patients.

MATERIALS AND METHODS

A comprehensive library of antimicrobials, including eight HIV protease inhibitors (nelfinavir [NFV], saquinavir, indinavir, ritonavir, amprenavir, atazanavir, lopinavir, and darunavir), was tested against a panel of pediatric leukemia cells by in vitro growth inhibition studies. Detailed target modulation studies were carried out by Western blot analyses. In addition, drug synergy experiments with conventional and novel antitumor agents were completed to identify effective treatment regimens for future clinical trials.

RESULTS

Several of the HIV protease inhibitors showed cytotoxicity at physiologically relevant concentrations (half-maximal inhibitory concentration values ranging from 1-24 µM). In particular, NFV was found to exhibit the most potent antileukemic properties across all cell lines tested. Mechanistic studies show that NFV leads to the induction of autophagy and apoptosis possibly through the induction of endoplasmic reticulum stress. Furthermore, interference with cell signaling pathways, including Akt and mTOR, was also noted. Finally, drug combination studies have identified agents with potential for synergy with NFV in its antileukemic activity. These include JQ1 (BET inhibitor), AT101 (Bcl-2 family inhibitor), and sunitinib (TK inhibitor).

CONCLUSION

Here, we show data demonstrating the potential of a previously unexplored group of drugs to address an unmet therapeutic need in pediatric oncology. The data presented provide preclinical supportive evidence and rationale for future studies of these agents for refractory leukemia in children.

Quantification of renal function following stereotactic body radiotherapy for pancreatic cancer: secondary dosimetric analysis of a prospective clinical trial

BACKGROUND

This is the first known study examining renal function following stereotactic body radiotherapy (SBRT) for pancreatic head adenocarcinoma.

METHODS

Thirty-eight borderline-resectable/unresectable patients, part of an ongoing prospective trial, underwent 3 cycles of gemcitabine/5-fluorouracil followed by SBRT (5 daily fractions of 5/6/7/8 Gy) and concurrent nelfinavir. Thereafter, in resectable cases, surgery was performed within 4-8 weeks. The last available pre-SBRT creatinine was recorded, along with the highest post-SBRT value. Glomerular filtration rate (GFR) was calculated by the commonly-utilized Modification of Diet in Renal Disease formula. GFR decline was defined as the post-SBRT nadir GFR minus the pre-SBRT GFR. Correlations with the V5-V30, and mean/maximum kidney doses was performed. Statistics included Pearson correlation, Mann-Whitney, and Fisher's exact tests.

RESULTS

The median total kidney volume was 355 cm³. Median dosimetric values were as follows: V5 (209 cm³), V10 (103 cm³), V15 (9 cm³), V20 (0 cm³), V25 (0 cm³); and mean (6.7 Gy) & maximum kidney dose (18.3 Gy). Median GFR change was -23 (range, -105 to 25) mL/min/1.73 cm². Of all dosimetric parameters, only V5 was significantly associated with changes in GFR (Pearson r = -0.40, p = 0.012). In patients with V5 < 210 cm³, median GFR change was -11.8 mL/min/1.73 cm², as compared with -37.1 mL/min/1.73 cm² change in those with V5 ≥ 210 cm³ (p = 0.02). A GFR change < -23 mL/min/1.73 cm² was observed in 6/20 (30%) patients with V5 < 210 cm³, versus 15/18 (83%) of those with V5 ≥ 210 cm³. Patients with V5 ≥ 210 cm³ were over ten times as likely to have GFR change < -23 mL/min/1.73 cm² (p = 0.003). Using linear regression, GFR change ≈ -0.1748 × V5(cm³) + 8.63.

CONCLUSIONS

In the first known analysis of renal function after pancreatic SBRT, evaluating patients on a prospective study, V5 ≥ 210 cm³ was associated with a post-SBRT GFR decline of >23 mL/min/1.73 cm². If V5 is kept <210 cm³, median GFR decline was only 11.8 mL/min/1.73 cm². Further validation is needed to ascertain definite dose-volume parameters and examine late renal decline.

Inhibition of MMP-9 expression by ritonavir or saquinavir is associated with inactivation of the AKT/Fra-1 pathway in cervical intraepithelial neoplasia cells

A reduced incidence and decreased clinical progression of uterine cervical intraepithelial neoplasia (CIN) has been observed in women infected with human immunodeficiency virus (HIV) treated with HIV-protease inhibitors (PIs). The HIV-PIs saquinavir (SQV) and ritonavir (RTV) have been demonstrated to efficiently inhibit invasion of human primary CIN cells by downregulating the expression of matrix metalloproteinase (MMP)-9. The present study further investigated the molecular mechanisms underlying the activity of SQV and RTV in CIN. The results of the present study indicate that the treatment of human primary CIN cells with SQV or RTV directly impairs events leading to MMP-9 expression, including the phosphorylation of AKT and the nuclear localisation of the Fos-related antigen transcription factor. In addition, neither SQV nor RTV affected the expression of human papilloma virus proteins, such as E6 or E7. In view of the important role that the AKT/Fra-1/MMP-9 signalling pathway serves in CIN progression to invasive cervical carcinoma, these data further support the use of HIV-PIs in the treatment of CIN in women infected with HIV and women who are not infected with HIV. Furthermore, the present study identified a molecular mechanism underlying the anti-invasive effects of SQV/RTV, providing useful information for the development of SQV/RTV derivatives, which may be employed as novel anticancer drugs.

Nelfinavir inhibits proliferation and induces DNA damage in thyroid cancer cells

The HIV protease inhibitor Nelfinavir (NFV) inhibits PI3K/AKT and MAPK/ERK signaling pathways, emerging targets in thyroid cancers. We examined the effects of NFV on cancer cells that derived from follicular (FTC), papillary (PTC) and anaplastic (ATC) thyroid cancers. NFV (1-20 µM) was tested in FTC133, BCPAP and SW1736 cell lines. The effects of NFV on cell proliferation were determined in vitro using real-time microscopy and by flow cytometry. DNA damage, apoptotic cell death and expression of molecular markers of epithelial-mesenchymal transition (EMT) were determined by Western blot and real-time PCR. Real-time imaging demonstrated that NFV (10 µM) increased the time required for the cell passage through the phases of cell cycle and induced DNA fragmentation. Growth inhibitory effects of NFV were associated with the accumulation of cells in G0/G1 phase, downregulation of cyclin D1 and cyclin-dependent kinase 4 (CDK4). NFV also induced the expression of γH2AX and p53BP1 indicating DNA damage. Treatment with NFV (20 µM) resulted in caspase-3 cleavage in all examined cells. NFV (20 µM) decreased the levels of total and p-AKT in PTEN-deficient FTC133 cells. NFV had no significant effects on total ERK and p-ERK in BRAF-positive BCPAP and SW1736 cells. NFV had no effects on the expression of EMT markers (Twist, Vimentin, E- and N-Cadherin), but inhibited the migration and decreased the abilities of thyroid cancer cells to survive in non-adherent conditions. We conclude that NFV inhibits proliferation and induces DNA damage in thyroid cancer cell lines. Our in vitro data suggest that NFV has a potential to become a new thyroid cancer therapeutic agent.

HIV-protease inhibitors for the treatment of cancer: Repositioning HIV protease inhibitors while developing more potent NO-hybridized derivatives?

The possible use of HIV protease inhibitors (HIV-PI) as new therapeutic option for the treatment of cancer primarily originated from their success in treating HIV-related Kaposi's sarcoma (KS). While these findings were initially attributed to immune reconstitution and better control of oncogenic viral infections, the number of reports on solid tumors, KS, lymphoma, fibrosarcoma, multiple myeloma and prostate cancer suggest other mechanisms for the anti-neoplastic activity of PIs. However, a major drawback for the possible adoption of HIV-PIs in the therapy of cancer relies on their relatively weak anticancer potency and important side effects. This has propelled several groups to generate derivatives of HIV-PIs for anticancer use, through modifications such as attachment of different moieties, ligands and transporters, including saquinavir-loaded folic acid conjugated nanoparticles and nitric oxide (NO) derivatives of HIV-PIs. In this article, we discuss the current preclinical and clinical evidences for the potential use of HIV-PIs, and of novel derivatives, such as saquinavir-NO in the treatment of cancer.

Dosimetric parameters correlate with duodenal histopathologic damage after stereotactic body radiotherapy for pancreatic cancer: Secondary analysis of a prospective clinical trial

PURPOSE

Prospectively assess relationships between dosimetric parameters and histopathologic/clinical duodenal toxicities in patients on a phase I trial for pancreatic cancer.

METHODS

Forty-six borderline resectable/unresectable patients were enrolled on a prospective trial testing neoadjuvant gemcitabine/5-fluorouracil followed by SBRT (5 daily fractions of 5-8Gy) and concurrent nelfinavir. Post-SBRT surgery was performed in 13 resectable patients, which constituted the patient population herein. Pathologic duodenal damage was assessed using predetermined criteria: 1, no/minimal; 2, moderate; and 3, marked damage. Clinical toxicities were assessed per the Clinical Terminology Criteria for Adverse Events (CTCAE). Duodenal dosimetric parameters included V5-V40 and mean/maximum doses. Spearman correlation and linear regression evaluated associations between dosimetric parameters and clinical/pathologic duodenal toxicity.

RESULTS

The median duodenal mean and maximum doses were 20 and 37Gy. Median duodenal V5-V40 were 64, 62, 52, 39, 27, 14, 5 and 0cc, respectively. The median duodenal damage score was 2 (four 1, eight 2, and one 3). Higher duodenal damage scores correlated with higher duodenal mean doses (r=0.75, p=0.003), V35 (r=0.61, p=0.03), V30 (r=0.67, p=0.01), V25 (r=0.68, p=0.01), V20 (r=0.56, p=0.05), and the planning target volume (PTV) mean (r=0.59, p=0.03) and maximum (r=0.61, p=0.03) doses. Clinical toxicities did not correlate with dosimetric parameters or duodenal pathologic damage.

CONCLUSIONS

Duodenal histologic damage correlates with mean duodenal dose, V20-V35, and PTV mean/maximum doses.

The HIV protease and PI3K/Akt inhibitor nelfinavir does not improve the curative effect of fractionated irradiation in PC-3 prostate cancer in vitro and in vivo

Background

Radiotherapy has a high curative potential in localized prostate cancer, however, there are still patients with locally advanced tumours who face a considerable risk of recurrence. Radiosensitization using molecular targeted drugs could help to optimize treatment for this high-risk group. The PI3K/Akt pathway is overexpressed in many prostate cancers and is correlated to radioresistance. Nelfinavir, an HIV protease inhibitor (HPI), was found to block this pathway and to radiosensitize cancer cells of different origin. This is the first study examining the effect of nelfinavir in combination with irradiation on prostate cancer cell survival in vitro as well as on growth time and local tumour control in vivo.

Methods

The in vitro effect of nelfinavir on radioresponse of PC-3 was tested by colony formation assay with 10 μM nelfinavir. In vivo, the effect of nelfinavir alone and in combination with irradiation was tested in nude mice carrying PC-3 xenografts. For evaluating tumour growth time, mice were treated with 80 mg nelfinavir/kg body weight, daily at 5 days per week over 6 weeks. Simultaneous irradiation with 30 fractions and total doses between 30 and 120 Gy was applied to calculate local tumour control for day 180 after treatment.

Results

Nelfinavir inhibited Akt phosphorylation at Ser473 and showed a minor but significant effect on clonogenic cell survival in vitro with slightly higher cell survival rates after combined treatment. The treatment of PC-3 xenografts with nelfinavir alone led to no significant increase of tumour growth time and no improvement of local tumour control.

Conclusions

Despite promising growth delay effects of nelfinavir in other tumour models and first clinical applications of this drug as anti-cancer agent, PC-3 prostate cancer cells express no or only minor sensitivity to nelfinavir treatment alone and no radiosensitizing effect in vitro or in vivo.

Nanoparticles for radiooncology: Mission, vision, challenges

Cancer is one of the leading non-communicable diseases with highest mortality rates worldwide. About half of all cancer patients receive radiation treatment in the course of their disease. However, treatment outcome and curative potential of radiotherapy is often impeded by genetically and/or environmentally driven mechanisms of tumor radioresistance and normal tissue radiotoxicity. While nanomedicine-based tools for imaging, dosimetry and treatment are potential keys to the improvement of therapeutic efficacy and reducing side effects, radiotherapy is an established technique to eradicate the tumor cells. In order to progress the introduction of nanoparticles in radiooncology, due to the highly interdisciplinary nature, expertise in chemistry, radiobiology and translational research is needed. In this report recent insights and promising policies to design nanotechnology-based therapeutics for tumor radiosensitization will be discussed. An attempt is made to cover the entire field from preclinical development to clinical studies. Hence, this report illustrates (1) the radio- and tumor-biological rationales for combining nanostructures with radiotherapy, (2) tumor-site targeting strategies and mechanisms of cellular uptake, (3) biological response hypotheses for new nanomaterials of interest, and (4) challenges to translate the research findings into clinical trials.

The interplay between cell signalling and the mevalonate pathway in cancer

The mevalonate (MVA) pathway is an essential metabolic pathway that uses acetyl-CoA to produce sterols and isoprenoids that are integral to tumour growth and progression. In recent years, many oncogenic signalling pathways have been shown to increase the activity and/or the expression of MVA pathway enzymes. This Review summarizes recent advances and discusses unique opportunities for immediately targeting this metabolic vulnerability in cancer with agents that have been approved for other therapeutic uses, such as the statin family of drugs, to improve outcomes for cancer patients.

Pharmacological eEF2K activation promotes cell death and inhibits cancer progression

Activation of the elongation factor 2 kinase (eEF2K) leads to the phosphorylation and inhibition of the elongation factor eEF2, reducing mRNA translation rates. Emerging evidence indicates that the regulation of factors involved in protein synthesis may be critical for controlling diverse biological processes including cancer progression. Here we show that inhibitors of the HIV aspartyl protease (HIV-PIs), nelfinavir in particular, trigger a robust activation of eEF2K leading to the phosphorylation of eEF2. Beyond its anti-viral effects, nelfinavir has antitumoral activity and promotes cell death. We show that nelfinavir-resistant cells specifically evade eEF2 inhibition. Decreased cell viability induced by nelfinavir is impaired in cells lacking eEF2K. Moreover, nelfinavir-mediated anti-tumoral activity is severely compromised in eEF2K-deficient engrafted tumors in vivo Our findings imply that exacerbated activation of eEF2K is detrimental for tumor survival and describe a mechanism explaining the anti-tumoral properties of HIV-PIs.

Targeted agents in GI radiotherapy: Clinical efficacy and side effects

Approximately 50% of all patients with cancer receive radiotherapy (RT) at some point during their treatment. Despite the advent of modern imaging and advances in planning and delivering highly-conformal and precise RT, further dose escalation to improve clinical outcome is often limited by the potential side-effects to adjacent tissues. Addition of chemotherapy to radiotherapy (CRT) has led to significant clinical improvements in many gastrointestinal malignancies but at the expense of increased toxicity as most chemotherapy drugs lack specificity. Targeted agents modulate specific biological pathways and can potentially enhance RT efficacy. However, so far, the majority of clinical studies incorporating targeted agents into RT and CRT have produced disappointing results in gastrointestinal malignancies. Also, we lack validated biomarkers and methods for monitoring and predicting the efficacy of these agents when combined with RT/CRT. In the present article, we will review the most important targeted therapies, and examine the efficacy and toxicity of these agents when combined with RT/CRT in gastrointestinal malignancies. The shortcomings as well as future challenges and perspectives for the successful use of these compounds with RT/CRT in future trials will also be outlined.

Redox Homeostasis and Cellular Antioxidant Systems: Crucial Players in Cancer Growth and Therapy

Reactive oxygen species (ROS) and their products are components of cell signaling pathways and play important roles in cellular physiology and pathophysiology. Under physiological conditions, cells control ROS levels by the use of scavenging systems such as superoxide dismutases, peroxiredoxins, and glutathione that balance ROS generation and elimination. Under oxidative stress conditions, excessive ROS can damage cellular proteins, lipids, and DNA, leading to cell damage that may contribute to carcinogenesis. Several studies have shown that cancer cells display an adaptive response to oxidative stress by increasing expression of antioxidant enzymes and molecules. As a double-edged sword, ROS influence signaling pathways determining beneficial or detrimental outcomes in cancer therapy. In this review, we address the role of redox homeostasis in cancer growth and therapy and examine the current literature regarding the redox regulatory systems that become upregulated in cancer and their role in promoting tumor progression and resistance to chemotherapy.

Is nelfinavir exposure associated with cancer incidence in HIV-positive individuals?

OBJECTIVE

Nelfinavir exhibits potent anticancer properties against a range of tumours. However, in 2006/2007, nelfinavir supplies were accidently contaminated with a carcinogen. This analysis investigated the association between nelfinavir use and cancer risk in HIV-positive persons.

DESIGN

Observational cohort study.

METHODS

D:A:D study data was analysed using Poisson regression models to examine associations between cancer incidence and cumulative nelfinavir exposure, current nelfinavir exposure, and exposure to nelfinavir between 1 July 2006-30 June 2007.

RESULTS

A total of 42 006 individuals (50% white, 73% male) contributed 303 005 person-years of follow-up between 1 January 2004 and 1 February 2014. At study enrolment, median age was 40 [interquartile range (IQR) 33-46] years and 8305 individuals had a history of nelfinavir use [median duration 1.7 (IQR 0.7-3.4) years]. During follow-up, nelfinavir was used by 2476 individuals for a median of 1.7 (IQR 0.7-3.8) years; 1063 were exposed to nelfinavir between 1 July 2006 and 30 June 2007. Overall, 2279 cancers were diagnosed at a rate of 0.75 [95% confidence interval (95% CI) 0.72-0.78] per 100 person-years. Neither greater cumulative exposure to nelfinavir [adjusted risk ratio (aRR) 0.93 for every additional 5 years, 95% CI 0.82-1.06, P = 0.26] nor current use of nelfinavir (aRR 0.98 vs other protease inhibitor use, 95% CI 0.68-1.41, P = 0.92) were associated with cancer risk. The adjusted risk of cancer for participants exposed to nelfinavir between 1 July 2006 and 30 June 2007 compared to those receiving other treatment over this period was 1.07 (95% CI 0.78-1.46, P = 0.68).

CONCLUSION

Nelfinavir use was not associated with a lower cancer incidence than other protease inhibitor regimens. As of February 2014, exposure to the 2006/2007 contamination of nelfinavir does not appear to be associated with increased cancer incidence.

Nelfinavir is effective against human cervical cancer cells in vivo: a potential treatment modality in resource-limited settings

Objective

The standard treatment for cervical cancer in developed countries includes surgery and chemoradiation, with standard of care lagging in developing countries. Even in the former case, treatment frequently yields recalcitrant tumors and women succumb to disease. Here we examine the impact of nelfinavir, an off-patent viral protease inhibitor, which has shown promise as an antineoplastic agent.

Methods

We evaluated the morphological and proliferative effects of the autophagy-stressing drug nelfinavir in normal and cisplatin-resistant cervical cancer cells. Immunofluorescent validation of autophagy markers was performed and the impact of nelfinavir in an in vivo model of tumor growth was determined.

Results

Nelfinavir exhibits cytotoxicity against both cisplatin-sensitive and -resistant ME-180 human cervical cancer cells in vitro and in vivo. Immunoblotting and immunofluorescence showed an expression of the autophagy marker LC3-II in response to nelfinavir treatment.

Conclusion

Nelfinavir, now available as an inexpensive generic orally dosed agent (Nelvir), is cytotoxic against cervical cancer cells. It acts by burdening the autophagy pathway to impair tumor cell survival and a modest induction of apoptosis. While further studies are needed to elucidate the optimal method of application of nelfinavir, it may represent an appealing global option for the treatment of cervical cancer.

Translation of Targeted Radiation Sensitizers into Clinical Trials

Over the past century, technologic advances have promoted the evolution of radiation therapy into a precise treatment modality allowing for the maximal administration of dose to tumors while sparing normal tissues. Coinciding with this technological maturation, systemic therapies have been combined with radiation in an effort to improve tumor control. Conventional cytotoxic agents have improved survival in several tumor types but cause increased toxicity due to effects on normal tissues. An increased understanding of tumor biology and the radiation response has led to the nomination of several pathways whose targeted inhibition has the potential to radiosensitize tumor cells with lesser effects on normal tissues. These pathways include those regulating the cell cycle, DNA damage repair, and mitogenic signaling. Few drugs targeting these pathways are in clinical practice, although many are in clinical trials. This review will describe the rationale for combining agents targeting these pathways with radiation, provide an overview of the current landscape in the clinical pipeline and attempt to outline the future steps.

The radiosensitizing effects of Nelfinavir on pancreatic cancer with and without pancreatic stellate cells

AIMS

We have previously shown in a phase I trial that nelfinavir (NFV) is safe with chemoradiation in PDAC with good signs for efficacy. Reverse translationally, we aimed to test the influence of PSCs on nelfinavir mediated radiosensitization to PDAC preclinically, because PDAC is very rich in desmoplasia and PSCs are known to mediate radioresistance.

METHODS

In a direct co-culture model of several PDAC cell lines with PSC we performed clonogenic assays +/- nelfinavir. This was repeated exposing cells to hypoxic conditions. In xenograft PDAC tumors we tested radiation +/- nelfinavir +/- PSC.

RESULTS

NFV sensitized both, PDAC only and PDAC cocultured with PSC (PDAC: Panc-1, MiaPaCa-2, PSN-1). In Panc-1 and PSN-1 this effect was larger +PSC compared to -PSC. Human pancreatic stellate cells (hPSC) were also sensitized by NFV which reduced p-FAK levels in hPSC, an effect that we previously found to sensitize specifically PDAC/PSC coculture. Contrarily, LY294002 reduced p-Akt in PSC (hPSC and LTC-14) but had no impact on PSC radiation survival. In vitro, nelfinavir sensitized Panc-1 and PSN-1 under normoxic and hypoxic conditions. In PSN-1 xenografts, +PSC led to faster tumor regrowth after radiation vs -PSC. The regrowth delay effect of nelfinavir after radiation was dramatically larger +PSC vs -PSC (time to reach 250mm(3) 183% vs 22%).

CONCLUSION

NFV mediated radiosensitization in PDAC with stroma is partly mediated by p-FAK inhibition (Chen et al., 2013). In vitro, NFV sensitizes both normoxic and hypoxic PDAC +/- PSC to a roughly similar extent. The dramatic increased effect of xenograft regrowth inhibition by nelfinavir in tumors with PSC is attributed to vascular normalization (Brunner et al., 2014) rather than direct modification of hypoxia as shown by the tumor regrowth after gemcitabine with NFV.

ARCII: A phase II trial of the HIV protease inhibitor Nelfinavir in combination with chemoradiation for locally advanced inoperable pancreatic cancer

BACKGROUND AND PURPOSE

Nelfinavir can enhance intrinsic radiosensitivity, reduce hypoxia and improve vascularity. We conducted a phase II trial combining nelfinavir with chemoradiotherapy (CRT) for locally advanced inoperable pancreatic cancer (LAPC).

MATERIALS AND METHODS

Radiotherapy (50.4Gy/28 fractions; boost to 59.4Gy/33 fractions) was administered with weekly gemcitabine and cisplatin. Nelfinavir started 3-10days before and was continued during CRT. The primary end-point was 1-year overall survival (OS). Secondary end-points included histological downstaging, radiological response, 1-year progression free survival (PFS), overall survival (OS) and treatment toxicity. An imaging sub-study (n=6) evaluated hypoxia ((18)F-Fluoromisonidazole-PET) and perfusion (perfusion CT) during induction nelfinavir.

RESULTS

The study closed after recruiting 23 patients, due to non-availability of Nelfinavir in Europe. The 1-year OS was 73.4% (90% CI: 54.5-85.5%) and median OS was 17.4months (90% CI: 12.8-18.8). The 1-year PFS was 21.8% (90% CI: 8.9-38.3%) and median PFS was 5.5months (90% CI: 4.1-8.3). All patients experienced Grade 3/4 toxicity, but many were asymptomatic laboratory abnormalities. Four of 6 patients on the imaging sub-study demonstrated reduced hypoxia and increased perfusion post-nelfinavir.

CONCLUSIONS

CRT combined with nelfinavir showed acceptable toxicity and promising survival in pancreatic cancer.

Clinical Trial of Oral Nelfinavir before and during Radiation Therapy for Advanced Rectal Cancer

PURPOSE

Nelfinavir, a PI3K pathway inhibitor, is a radiosensitizer that increases tumor blood flow in preclinical models. We conducted an early-phase study to demonstrate the safety of nelfinavir combined with hypofractionated radiotherapy (RT) and to develop biomarkers of tumor perfusion and radiosensitization for this combinatorial approach.

EXPERIMENTAL DESIGN

Ten patients with T3-4 N0-2 M1 rectal cancer received 7 days of oral nelfinavir (1,250 mg b.i.d.) and a further 7 days of nelfinavir during pelvic RT (25 Gy/5 fractions/7 days). Perfusion CT (p-CT) and DCE-MRI scans were performed pretreatment, after 7 days of nelfinavir and prior to the last fraction of RT. Biopsies taken pretreatment and 7 days after the last fraction of RT were analyzed for tumor cell density (TCD).

RESULTS

There were 3 drug-related grade 3 adverse events: diarrhea, rash, and lymphopenia. On DCE-MRI, there was a mean 42% increase in medianKtrans, and a corresponding median 30% increase in mean blood flow on p-CT during RT in combination with nelfinavir. Median TCD decreased from 24.3% at baseline to 9.2% in biopsies taken 7 days after RT (P= 0.01). Overall, 5 of 9 evaluable patients exhibited good tumor regression on MRI assessed by tumor regression grade (mrTRG).

CONCLUSIONS

This is the first study to evaluate nelfinavir in combination with RT without concurrent chemotherapy. It has shown that nelfinavir-RT is well tolerated and is associated with increased blood flow to rectal tumors. The efficacy of nelfinavir-RT versus RT alone merits clinical evaluation, including measurement of tumor blood flow.

Treatment with the HIV protease inhibitor nelfinavir triggers the unfolded protein response and may overcome proteasome inhibitor resistance of multiple myeloma in combination with bortezomib: a phase I trial (SAKK 65/08)

Downregulation of the unfolded protein response mediates proteasome inhibitor resistance in multiple myeloma. The Human Immunodeficieny Virus protease inhibitor nelfinavir activates the unfolded protein response in vitro. We determined dose-limiting toxicity and recommended dose for phase II of nelfinavir in combination with the proteasome inhibitor bortezomib. Twelve patients with advanced hematologic malignancies were treated with nelfinavir (2500-5000 mg/day p.o., days 1-14, 3+3 dose escalation) and bortezomib (1.3 mg/m(2), days 1, 4, 8, 11; 21-day cycles). A run in phase with nelfinavir monotherapy allowed pharmakokinetic/pharmakodynamic assessment of nelfinavir in the presence or absence of concomittant bortezomib. End points included dose-limiting toxicity, activation of the unfolded protein response, proteasome activity, toxicity and response to trial treatment. Nelfinavir 2×2500 mg was the recommended phase II dose identified. Nelfinavir alone significantly up-regulated expression of proteins related to the unfolded protein response in peripheral blood mononuclear cells and inhibited proteasome activity. Of 10 evaluable patients in the dose escalation cohort, 3 achieved a partial response, 4 stable disease for 2 cycles or more, while 3 had progressive disease as best response. In an exploratory extension cohort with 6 relapsed, bortezomib-refractory, lenalidomide-resistant myeloma patients treated at the recommended phase II dose, 3 reached a partial response, 2 a minor response, and one progressive disease. The combination of nelfinavir with bortezomib is safe and shows promising activity in advanced, bortezomib-refractory multiple myeloma. Induction of the unfolded protein response by nelfinavir may overcome the biological features of proteasome inhibitor resistance. (clinicaltrials.gov identifier: 01164709).