Mutations in LRRK2 cause autosomal dominant Parkinson's disease (PD). LRRK2 encodes a multi-domain protein containing GTPase and kinase domains, and putative protein–protein interaction domains. Familial PD mutations alter the GTPase and kinase activity of LRRK2 in vitro. LRRK2 is suggested to regulate a number of cellular pathways although the underlying mechanisms are poorly understood. To explore such mechanisms, it has proved informative to identify LRRK2-interacting proteins, some of which serve as LRRK2 kinase substrates. Here, we identify common interactions of LRRK2 with members of the dynamin GTPase superfamily. LRRK2 interacts with dynamin 1–3 that mediate membrane scission in clathrin-mediated endocytosis and with dynamin-related proteins that mediate mitochondrial fission (Drp1) and fusion (mitofusins and OPA1). LRRK2 partially co-localizes with endosomal dynamin-1 or with mitofusins and OPA1 at mitochondrial membranes. The subcellular distribution and oligomeric complexes of dynamin GTPases are not altered by modulating LRRK2 in mouse brain, whereas mature OPA1 levels are reduced in G2019S PD brains. LRRK2 enhances mitofusin-1 GTP binding, whereas dynamin-1 and OPA1 serve as modest substrates of LRRK2-mediated phosphorylation in vitro. While dynamin GTPase orthologs are not required for LRRK2-induced toxicity in yeast, LRRK2 functionally interacts with dynamin-1 and mitofusin-1 in cultured neurons. LRRK2 attenuates neurite shortening induced by dynamin-1 by reducing its levels, whereas LRRK2 rescues impaired neurite outgrowth induced by mitofusin-1 potentially by reversing excessive mitochondrial fusion. Our study elucidates novel functional interactions of LRRK2 with dynamin-superfamily GTPases that implicate LRRK2 in the regulation of membrane dynamics important for endocytosis and mitochondrial morphology.

Agents that chemically modify DNA form a backbone of many cancer treatments. A key problem for DNA modifying agents is lack of specificity. To address this issue, we designed novel molecular scaffolds, termed An-Hq and An-Hq2, which are activated by a hallmark of some cancers: elevated concentrations of reactive oxygen species. Elevated reactive oxygen species are linked to oncogenesis and is found to increase in several aggressive cancers. The agents are quinones that, upon oxidation, form highly electrophilic species. In vitro studies identified the mode of addition to DNA. The aniline portion of An-Hq serves to enhance nucleophilic addition to the ethyl phenyl ether instead of forming common Michael additions. Structural characterization showed the agents add to 2′-deoxyguanosine at the N2,N3-positions. The product formed is a bulky hydroxy-N2,3-benzetheno-2′-deoxyguanosine adduct. In addition, the oxidatively activated agents added to 2′-deoxyadenosine and 2′-deoxycytidine, but not thymidine or 2′-deoxyinosine. These findings are confirmed by primer extension analysis of a 392 base pair DNA. The full-length primer extension product was reduced by 69.0 ± 0.6% upon oxidative activation of An-Hq2 compared to controls. Little sequence dependence was observed with 76% of guanine, adenine, and cytosine residues showing an increase in extension stops between two and four fold above controls. Benzetheno-nucleobase addition to double stranded DNA was confirmed by LC/MS of a self-complementary oligonucletide. Experiments were carried out to confirm in vivo DNA damage. Because of the lesion identified in vitro, we reasoned that nucleotide excision repair should be involved in reversing the effects of these oxidatively activated agents and enhance toxicity in Drosophila melanogaster. Using an RNAi based approach, Ercc1 was silenced and survival monitored after injection of an agent. As expected, bulky cross-linking DNA modifying agents, cisplatin and chlorambucil, showed statistically significant enhanced toxicity in Drosophila with silenced Ercc1. In addition, 5-fluorouracil, which does not produce bulky lesions, showed no selective toxicity. An-Hq and An-Hq2 showed statistically significant toxicity in Drosophila with silenced Ercc1. Examination of cytotoxicity shows renal carcinoma cell lines as a target of these agents with a median IC50 of 1.8 μM. Taken together, this data shows that the designed oxidatively-activated agents form distinct, bulky DNA modifications that prove difficult for cancer cells possessing an elevated reactive oxygen species phenotype to overcome. The modification produced is relatively unique among anticancer agents.

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Background: Māori, Indigenous peoples of New Zealand (NZ) are twice as likely to die after a diagnosis of cancer compared to non-Māori. Cancer pathways are not designed for Māori health gain and are not pandemic resilient. Māori receive delayed poorer quality treatment and those with comorbidities are undertreated [1]. Existing inequities from time of referral to cancer services through to treatment were exacerbated by the COVID-19 response in Aotearoa NZ. Coordination of care is crucial for Māori patients and whānau (family), but poorly developed along this early part of the cancer pathway. In addition, care quality is not well monitored, and the current pathway is vulnerable to changes created by pandemic conditions. Aims: This study seeks to co-design, implement and evaluate a holistic cultural and clinical cancer service that is patient and whānau centred; the Whānau Hauora Integrated Response Initiative (WHIRI) programme. This comprehensive, pandemic resilient, racism-free, hauora (wellbeing) enhancing and responsive model of care will be designed for the early part of the secondary care cancer pathway. Design and Method: The WHIRI programme includes navigation, a holistic whānau/family hauora assessment tool, proactive management by a team of clinicians and a team responsible for making systems changes. WHIRI was launched mid-pandemic (early 2020) for kaumātua (elderly Māori) with long-term conditions and ran for 3 months. During COVID we found that WHIRI had the potential to change hospital systems and improve experiences for patients and whānau. WHIRI ensures the provision of best-practice timely treatment for Māori patients and could make large gains in closing the survival gap between Māori and non-Māori in the short- to medium-term, leading to reductions in Māori cancer deaths. We plan to redesign WHIRI into a cancer programme that functions effectively in all COVID levels using qualitative Kaupapa Māori methodology. Key to this methodology is partnerships with patients, whānau, cancer clinicians, Māori navigators and The Cancer Control Agency New Zealand. We will present our methods and co-design model of cancer care. We will outline the potential to expand the model nationally with reach from primary care all the way through to palliative care. It will also provide a platform for future research to measure the impact of WHIRI on cancer and whānau care. 1. Hill S, Sarfati D, Blakely T, Robson B, Purdie G, Chen J, et al. Survival disparities in Indigenous and non-Indigenous New Zealanders with colon cancer: the role of patient comorbidity, treatment and health service Citation Format: Nina Scott, Myra Ruka, Amy R. Jones. Cancer WHIRI research: Improving the early cancer pathway for indigenous NZ peoples [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 5278.