Perspectives of Health Care Providers on Peer Support for Adolescents with Cancer in Pediatrics

Health care providers (HCPs) play a key role in psychosocial care of adolescents with cancer (AWC) and present a unique perspective. This prospective study included a brief survey followed by an interview, seeking to understand HCPs' viewpoints on peer support needs of AWC. Participants were 10 multidisciplinary HCPs with 5-30 years of experience. Three key themes found were: observations made and relationships with AWC; challenges to providing support; and potential peer support interventions. HCPs want to provide peer support resources but lack adequate information. Next steps: interventions should include information dissemination to all HCPs caring for AWC.

Peer Support Perspectives of Parents of Adolescents with Cancer in Pediatrics

Parents of adolescents with cancer (AWC) provide critical support throughout the cancer journey and could offer key insights into support needs. This prospective study aimed to obtain parent perspectives on peer support needs of AWC. Ten individual parents (9 mothers and 1 father) completed a survey and a semistructured interview. Four themes were identified: cancer journey challenges; emotions, reactions, and coping; personal support preferences; and AWC's support needs. Parents recognized that AWC require various support, but lacked insight into their specific peer support desires. Next step interventions should focus on peer support for AWC, while also incorporating peer support for parents.

Abstract 1431: ADO contributes to tumour initiating phenotypes

2-aminoethanethiol dioxygenase (ADO) is a thiol dioxygenase that plays a role in both metabolism and protein stability. ADO directly metabolizes cysteamine to produce hypotaurine and taurine in mammals. ADO has also been recently identified to promote oxygen dependent stability of a subset of substrates involved in the N-degron pathway in mammals (IL32, RGS4 and RGS5). The ability of ADO to target protein stability of signaling molecules suggests that it may have the potential to transduce rapid responses to hypoxia and affect tumour initiation and progression phenotypes. Here, we have successfully knocked down and knocked out ADO using two independent siRNAs and clustered regularly interspaced short palindromic repeats associated protein 9 (CRISPR-Cas9) system, respectively. We have assessed proliferation and migration through the Incucyte® ZOOM system by imaging cell confluency over time. Survival was assessed through a clonogenic assay. siRNA mediated knockdown of ADO in cervical (HeLa and SiHa), pancreatic (Panc1 and Capan2) and liver (SNU499 and Huh6) cancer cell lines drastically reduced proliferation, survival, and migration in normoxia. These results were also replicated in hypoxia (0.2% O2) across all 6 cell lines. Out of the 6 cell lines, the liver cancer cell lines were most drastically affected by the knockdown of ADO. This phenotype was replicated in the ADO KO cell lines. Taken together, these data suggest that expression of ADO may contribute to phenotypes that induce aggressive tumour phenotypes by targeting the stability of specific proteins and altering cellular metabolism in mammals.

Citation Format: Sandy Che-Eun Serena Lee, Andrea Hye An Pyo, Marianne Koritzinsky. ADO contributes to tumour initiating phenotypes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1431.

Abstract 3559: Protein secretion rates of VEGF and CA9 in normoxia and hypoxia

Tumor hypoxia results in poor patient outcome due to treatment resistance as well as biological changes that stimulate angiogenesis, vasculogenesis, migration, invasion and immune suppression. These hypoxia-induced adverse biological changes are often mediated by membrane bound or secreted proteins through transcriptional and translational upregulation. Thus, understanding the regulation of how secreted proteins in hypoxia can therefore reveal novel therapeutic targets. Proteins that traverse through the secretory pathway form disulfide bonds in the endoplasmic reticulum (ER). Recent data from our lab have demonstrated that disulfide bond formation remains incomplete in ER cargo proteins like LDLR and Flu-HA in the absence of oxygen. To address whether hypoxia-induced proteins were likewise impaired, radioactive pulse chase assays were performed to measure disulfide bond formation and secretion capacity under both normoxic and hypoxic conditions. Here, we demonstrate that both hypoxia induced proteins carbonic anhydrase 9 (CA9) and vascular endothelial growth factor (VEGF) complete disulfide bond formation and are secreted with equal kinetics under hypoxia and normoxia. These proteins hence have a superior ability to be expressed in the absence of oxygen. Additionally, in a global in silico analysis of all proteins that traverse through the ER, we discovered that hypoxia-induced proteins on average contain fewer free cysteines and shorter-range disulfide bonds in comparison to other proteins. These traits may contribute to their superior ability to form correct disulfide bonds in hypoxia. These data show that the ability of proteins to form native disulfide bonds in hypoxia varies widely which can ultimately contribute to their expression in the extracellular space.

Citation Format: Sandy Che-Eun Serena Lee, Fiana Levitin, Stephanie Hulme, Ryan Rumantir, Jenna Sykes, Marianne Koritzinsky. Protein secretion rates of VEGF and CA9 in normoxia and hypoxia [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3559.