High-Throughput Screening Identifies Idasanutlin as a Resensitizing Drug for Venetoclax-Resistant Neuroblastoma Cells

Venetoclax Use in Paediatric Haemato-Oncology Centres in Poland: A 2022 Survey

Venetoclax, the best established BH3-mimetic, is a practice-changing proapoptotic drug in blood cancers in adults. In paediatrics the data are fewer but exciting results were recently presented in relapsed or refractory leukaemias demonstrating significant clinical activity. Importantly, the in-terventions could be potentially molecularly guided as vulnerabilities to BH3-mimetics were re-ported. Currently venetoclax is not incorporated into paediatric treatment schedules in Poland but it has been already used in patients that failed conventional therapy in Polish paediatric haemato-oncology departments. The aim of the study was to gather clinical data and correlates of all paediatric patients treated so far with venetoclax in Poland. We set out to gather this experience to help choose the right clinical context for the drug and stimulate further research. The questionnaire regarding the use of venetoclax was sent to all 18 Polish paediatric haemato-oncology centres. The data as available in November 2022 were gathered and analysed for the diagnoses, triggers for the intervention, treatment schedules, outcomes and molecular associations. We received response from 11 centres, 5 of which administered venetoclax to their patients. Clinical benefit, in most cases consistent with hematologic complete remission (CR), was reported in 5 patients out of ten, whereas 5 patient did not show clinical benefit from the intervention. Importantly, patients with CR included subtypes expected to show venetoclax vulnerability, such as poor-prognosis ALL with TCF::HLF fusion. We believe BH3-mimetics have clinical activity in children and should be available to pae-diatric haemato-oncology practitioners in well-selected applications.

Preclinical In Vitro Investigation of MDM2 Inhibition in Combination with Antiangiogenic Therapy for Breast Cancer Treatment

Background: Combining antiangiogenic drugs with other chemotherapeutic drugs has been found to produce superior therapeutic outcomes and prevent drug resistance in a variety of cancers. Methods: Experimental assays such as the MTT assay, flow cytometry, western blotting, and qPCR have been used to evaluate the efficacy of combination therapy. Results: When compared to controls and monotherapies, the combination treatment of axitinib and idasanutlin demonstrated a substantial decrease in cell viability at lower doses, a significant decrease in migration, and a shift toward early and late apoptosis. This study examined major apoptotic, metastatic, and angiogenic factors, including MDM2, p21, BCL-2, BCL-XL, and MMP9, which have showed differential expressions at the protein and mRNA levels after combination. Axitinib and idasanutlin decreased tumorigenesis and migration in vitro in the MCF-7 cell line when compared to other chemotherapeutic medications. The suggested mechanisms of the antitumorigenic effect of the combination therapy may depend on its capacity to promote the production of apoptotic markers and reduce antiapoptotic markers. Conclusions: Treatments with axitinib and idasanutlin demonstrated effective therapeutic targeting of the primary angiogenic growth factor and, consequently, the pro-metastatic arbitrators. This will not only eliminate cancer cells but also stop other malignant processes and ultimately reduce the metastatic cascade.

MEK inhibition causes BIM stabilization and increased sensitivity to BCL-2 family member inhibitors in RAS-MAPK-mutated neuroblastoma

Introduction

Mutations affecting the RAS-MAPK pathway occur frequently in relapsed neuroblastoma tumors and are associated with response to MEK inhibition in vitro. However, these inhibitors alone do not lead to tumor regression in vivo, indicating the need for combination therapy.

Methods and results

Via high-throughput combination screening, we identified that the MEK inhibitor trametinib can be combined with BCL-2 family member inhibitors, to efficiently inhibit growth of neuroblastoma cell lines with RAS-MAPK mutations. Suppressing the RAS-MAPK pathway with trametinib led to an increase in pro-apoptotic BIM, resulting in more BIM binding to anti-apoptotic BCL-2 family members. By favoring the formation of these complexes, trametinib treatment enhances sensitivity to compounds targeting anti-apoptotic BCL-2 family members. In vitro validation studies confirmed that this sensitizing effect is dependent on an active RAS-MAPK pathway. In vivo combination of trametinib with BCL-2 inhibitors led to tumor inhibition in NRAS-mutant and NF1-deleted xenografts.

Conclusion

Together, these results show that combining MEK inhibition with BCL-2 family member inhibition could potentially improve therapeutic outcomes for RAS-MAPK-mutated neuroblastoma patients.

Data-driven approaches to advance research and clinical care for pediatric cancer

Pediatric cancer is a rare disease with a distinct etiology and mutational landscape compared with adult cancer. Multi-omics profiling of retrospective and prospective cohorts coupled with innovative computational analysis have been instrumental in uncovering mechanisms of tumorigenesis and drug resistance that are now informing pediatric cancer clinical therapy. In this review we present the major data resources of pediatric cancer and actionable insights into pediatric cancer etiology stemming from the identification of oncogenic gene fusions, mutational signature analysis, systems biology, cancer predisposition and survivorship studies - that have led to improved clinical diagnosis, discovery of new drug-targets, pharmacological therapy, and screening for genetic predisposition. Ultimately, integration of large-scale omics datasets generated through international collaboration is required to maximize the power of data-driven approaches to advance pediatric cancer research informing clinical therapy.