Modulating sensitivity to drug-induced apoptosis: the future for chemotherapy?

Drug resistance is a fundamental problem in the treatment of most common human cancers. Our understanding of the cellular mechanisms underlying death and survival has allowed the development of rational approaches to overcoming drug resistance. The mitogen activated protein kinase family of protein serine/threonine kinases has been implicated in this complex web of signalling, with some members acting to enhance death and other members to prevent it. A recent publication by MacKeigan et al is the first to demonstrate an enhancement of drug-induced cell death by simultaneous blockade of MEK-mediated survival signalling, and offers the potential for targeted adjuvant therapy as a means of overcoming drug resistance

PARC:a phase I/II study evaluating the safety and activity of pegylated recombinant human arginase BCT-100 in relapsed/refractory cancers of children and young adults

Background: The survival for many children with relapsed/refractory cancers remains poor despite advances in therapies. Arginine metabolism plays a key role in the pathophysiology of a number of pediatric cancers. We report the first in child study of a recombinant human arginase, BCT-100, in children with relapsed/refractory hematological, solid or CNS cancers.Procedure: PARC was a single arm, Phase I/II, international, open label study. BCT-100 was given intravenously over one hour at weekly intervals. The Phase I section utilized a modified 3 + 3 design where escalation/de-escalation was based on both the safety profile and the complete depletion of arginine (defined as adequate arginine depletion; AAD <8μM arginine in the blood after 4 doses of BCT-100). The Phase II section was designed to further evaluate the clinical activity of BCT-100 at the pediatric RP2D determined in the Phase I section, by recruitment of patients with pediatric cancers into 4 individual groups. A primary evaluation of response was conducted at eight weeks with patients continuing to receive treatment until disease progression or unacceptable toxicity.Results: 49 children were recruited globally. The Phase I cohort of the trial established the Recommended Phase II Dose of 1600U/kg iv weekly in children, matching that of adults. BCT-100 was very well tolerated. No responses defined as a CR, CRi or PR were seen in any cohort within the defined 8 week primary evaluation period. However a number of these relapsed/refractory patients experienced prolonged radiological SD.Conclusion: Arginine depletion is a clinically safe and achievable strategy in children with cancer. The RP2D of BCT-100 in children with relapsed/refractory cancers is established at 1600U/kg intravenously weekly and can lead to sustained disease stability in this hard to treat population.Clinical trial registration: EudraCT, 2017-002762-44; ISRCTN, 21727048; and ClinicalTrials.gov, NCT03455140

Factors associated with recurrence and survival length following relapse in patients with neuroblastoma

Background: Despite therapeutic advances, survival following relapse for neuroblastoma patients remains poor. We investigated clinical and biological factors associated with length of progression-free and overall survival following relapse in UK neuroblastoma patients. Methods: All cases of relapsed neuroblastoma, diagnosed during 1990-2010, were identified from four Paediatric Oncology principal treatment centres. Kaplan-Meier and Cox regression analyses were used to calculate post-relapse overall survival (PROS), post-relapse progression-free survival (PRPFS) between relapse and further progression, and to investigate influencing factors. Results: One hundred eighty-nine cases were identified from case notes, 159 (84.0%) high risk and 17 (9.0%), unresectable, MYCN non-amplified (non-MNA) intermediate risk (IR). For high-risk patients diagnosed >2000, median PROS was 8.4 months (interquartile range (IQR)=3.0-17.4) and median PRPFS was 4.7 months (IQR=2.1-7.1). For IR, unresectable non-MNA patients, median PROS was 11.8 months (IQR 9.0-51.6) and 5-year PROS was 24% (95% CI 7-45%). MYCN amplified (MNA) disease and bone marrow metastases at diagnosis were independently associated with worse PROS for high-risk cases. Eighty percent of high-risk relapses occurred within 2 years of diagnosis compared with 50% of unresectable non-MNA IR disease. Conclusions: Patients with relapsed HR neuroblastomas should be treatment stratified according to MYCN status and PRPFS should be the primary endpoint in early phase clinical trials. The failure to salvage the majority of IR neuroblastoma is concerning, supporting investigation of intensification of upfront treatment regimens in this group to determine whether their use would diminish likelihood of relapse

Increasing frailty is associated with higher prevalence and reduced recognition of delirium in older hospitalised inpatients: results of a multi-centre study

Purpose: Delirium is a neuropsychiatric disorder delineated by an acute change in cognition, attention, and consciousness. It is common, particularly in older adults, but poorly recognised. Frailty is the accumulation of deficits conferring an increased risk of adverse outcomes. We set out to determine how severity of frailty, as measured using the CFS, affected delirium rates, and recognition in hospitalised older people in the United Kingdom. Methods: Adults over 65 years were included in an observational multi-centre audit across UK hospitals, two prospective rounds, and one retrospective note review. Clinical Frailty Scale (CFS), delirium status, and 30-day outcomes were recorded. Results: The overall prevalence of delirium was 16.3% (483). Patients with delirium were more frail than patients without delirium (median CFS 6 vs 4). The risk of delirium was greater with increasing frailty [OR 2.9 (1.8–4.6) in CFS 4 vs 1–3; OR 12.4 (6.2–24.5) in CFS 8 vs 1–3]. Higher CFS was associated with reduced recognition of delirium (OR of 0.7 (0.3–1.9) in CFS 4 compared to 0.2 (0.1–0.7) in CFS 8). These risks were both independent of age and dementia. Conclusion: We have demonstrated an incremental increase in risk of delirium with increasing frailty. This has important clinical implications, suggesting that frailty may provide a more nuanced measure of vulnerability to delirium and poor outcomes. However, the most frail patients are least likely to have their delirium diagnosed and there is a significant lack of research into the underlying pathophysiology of both of these common geriatric syndromes

Bioengineering approaches to study multidrug resistance in tumor cells

The ability of cancer cells to become resistant to chemotherapeutic agents is a major challenge for the treatment of malignant tumors. Several strategies have emerged to attempt to inhibit chemoresistance, but the fact remains that resistance is a problem for every effective anticancer drug. The first part of this review will focus on the mechanisms of chemoresistance. It is important to understand the environmental cues, transport limitations and the cellular signaling pathways associated with chemoresistance before we can hope to effectively combat it. The second part of this review focuses on the work that needs to be done moving forward. Specifically, this section focuses on the necessity of translational research and interdisciplinary directives. It is critical that the expertise of oncologists, biologists, and engineers be brought together to attempt to tackle the problem. This discussion is from an engineering perspective, as the dialogue between engineers and other cancer researchers is the most challenging due to non-overlapping background knowledge. Chemoresistance is a complex and devastating process, meaning that we urgently need sophisticated methods to study the process of how cells become resistant

Hypoxia-Induced Cytotoxic Drug Resistance in Osteosarcoma Is Independent of HIF-1Alpha

Survival rates from childhood cancer have improved dramatically in the last 40 years, such that over 80% of children are now cured. However in certain subgroups, including metastatic osteosarcoma, survival has remained stubbornly poor, despite dose intensive multi-agent chemotherapy regimens, and new therapeutic approaches are needed. Hypoxia is common in adult solid tumours and is associated with treatment resistance and poorer outcome. Hypoxia induces chemotherapy resistance in paediatric tumours including neuroblastoma, rhabdomyosarcoma and Ewing’s sarcoma, in vitro, and this drug resistance is dependent on the oxygen-regulated transcription factor hypoxia inducible factor-1 (HIF-1). In this study the effects of hypoxia on the response of the osteosarcoma cell lines 791T, HOS and U2OS to the clinically relevant cytotoxics cisplatin, doxorubicin and etoposide were evaluated. Significant hypoxia-induced resistance to all three agents was seen in all three cell lines and hypoxia significantly reduced drug-induced apoptosis. Hypoxia also attenuated drug-induced activation of p53 in the p53 wild-type U2OS osteosarcoma cells. Drug resistance was not induced by HIF-1α stabilisation in normoxia by cobalt chloride nor reversed by the suppression of HIF-1α in hypoxia by shRNAi, siRNA, dominant negative HIF or inhibition with the small molecule NSC-134754, strongly suggesting that hypoxia-induced drug resistance in osteosarcoma cells is independent of HIF-1α. Inhibition of the phosphoinositide 3-kinase (PI3K) pathway using the inhibitor PI-103 did not reverse hypoxia-induced drug resistance, suggesting the hypoxic activation of Akt in osteosarcoma cells does not play a significant role in hypoxia-induced drug resistance. Targeting hypoxia is an exciting prospect to improve current anti-cancer therapy and combat drug resistance. Significant hypoxia-induced drug resistance in osteosarcoma cells highlights the potential importance of hypoxia as a target to reverse drug resistance in paediatric osteosarcoma. The novel finding of HIF-1α independent drug resistance suggests however other hypoxia related targets may be more relevant in paediatric osteosarcoma