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    The Victorian Comprehensive Cancer Centre lung cancer clinical audit: collecting the UK National Lung Cancer Audit data from hospitals in Australia
    Mileshkin, L ; Dunn, C ; Cross, H ; Duffy, M ; Shaw, M ; Antippa, P ; Mitchell, P ; Akhurst, T ; Conron, M ; Moore, M ; Philip, J ; Bartlett, J ; Emery, J ; Zambello, B (WILEY, 2019-08)
    BACKGROUND: Clinical audit may improve practice in cancer service provision. The UK National Lung Cancer Audit (NLCA) collects data for all new cases of thoracic cancers. AIM: To collect similar data for our Victorian patients from six hospitals within the Victorian Comprehensive Cancer Centre and associated Western and Central Melbourne Integrated Cancer Service. METHODS: We conducted a retrospective audit of all newly diagnosed patients with lung cancer and mesothelioma in 2013 across the six Victorian Comprehensive Cancer Centre/Western and Central Melbourne Integrated Cancer Service hospitals. The objectives were to adapt the NLCA data set for use in the Australian context, to analyse the findings using descriptive statistics and to determine feasibility of implementing a routine, ongoing audit similar to that in the UK. Individual data items were adapted from the NLCA by an expert steering committee. Data were collated from the Victorian Cancer Registry, Victorian Admitted Episodes Dataset and individual hospital databases. Individual medical records were audited for missing data. RESULTS: Eight hundred and forty-five patients were diagnosed across the sites in 2013. Most were aged 65-80 (55%) and were male (62%). Most had non-small-cell lung cancer (81%) with 9% diagnosed with small cell lung cancer and 2% with mesothelioma. Data completeness varied significantly between fields. For those with higher levels of completeness, headline indicators of clinical care were comparable with NLCA data. The Victorian population seem to lack access to specialist lung cancer nurse services. CONCLUSION: Lung cancer care at participating hospitals appeared to be comparable with the UK in 2013. In future, prospective data collection should be harmonised across sites and correlated with survival outcomes. One area of concern was a lack of documented access to specialist nursing services.
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    Inhibition of RNA polymerase I transcription activates targeted DNA damage response and enhances the efficacy of PARP inhibitors in high-grade serous ovarian cancer.
    Sanij, E ; Hannan, K ; Xuan, J ; Yan, S ; Ahern, JA ; Trigos, AS ; Brajanovski, N ; Son, J ; Chan, KT ; Kondrashova, O ; Lieschke, E ; Wakefield, MJ ; Ellis, S ; Cullinane, C ; Poortinga, G ; Khanna, KK ; Mileshkin, L ; McArthur, GA ; Soong, J ; Berns, EM ; Hannan, RD ; Scott, CL ; Sheppard, KE ; Pearson, RB (AMER ASSOC CANCER RESEARCH, 2020-07)
    Abstract Introduction: PARP inhibitors (PARPi) have revolutionized disease management of patients with homologous recombination (HR) DNA repair-deficient high-grade serous ovarian cancer (HGSOC). However, acquired resistance to PARPi is a major challenge in the clinic. The specific inhibitor of RNA polymerase I (Pol I) transcription of ribosomal RNA genes (rDNA) has demonstrated single-agent antitumor activity in p53 wild-type and p53-mutant hematologic malignancies (first-in-human trial, dose escalation study of CX-5461 at Peter MacCallum Cancer Centre) (Khot et al., Cancer Discov 2019). CX-5461 has also been reported to exhibit synthetic lethality with BRCA1/2 deficiency through stabilization of G-quadruplex DNA (GQ) structures. Here, we investigate the efficacy of CX-5461 in treating HGSOC. Experimental Design: The mechanisms by which CX-5461 induces DNA damage response (DDR) and displays synthetic lethality in HR-deficient HGSOC cells are explored. We present in vivo data of mice bearing two functionally and genomically profiled HGSOC-patient-derived xenograft (PDX)s treated with CX-5461 and olaparib, alone and in combination. We also investigate CX-5461-sensitivity gene expression signatures in primary and relapsed HGSOC. Results: Utilizing ovarian cancer cell lines, we demonstrate that sensitivity to CX-5461 is associated with “BRCA1 mutation” and “MYC targets” gene expression signatures. In addition, sensitivity to CX-5461 is associated with high basal rates of Pol I transcription. Importantly, we demonstrate a novel mechanism for CX-5461 synthetic lethal interaction with HR deficiency mediated through the induction of replication stress at rDNA repeats. Our data reveal CX-5461-mediated DDR in HR-deficient cells does not involve stabilization of GQ structures as previously proposed. On the contrary, we show definitively that CX-5461 inhibits Pol I recruitment leading to rDNA chromatin defects including stabilization of R-loops, single-stranded DNA, and replication stress at the rDNA. Mechanistically, we demonstrate CX-5461 leads to replication-dependent DNA damage involving MRE11-dependent degradation of replication forks. Importantly, CX-5461 has a different sensitivity spectrum to olaparib and cooperates with PARPi in exacerbating replication stress, leading to enhanced therapeutic efficacy in HR-deficient HGSOC-PDX in vivo compared to single-agent treatment of both drugs. Further, CX-5461 exhibits single-agent efficacy in olaparib-resistant HGSOC-PDX overcoming PARPi-resistance mechanisms involving fork protection. Importantly, we identify CX-5461-sensitivity gene expression signatures in primary and relapsed HGSOC. Conclusions: CX-5461 is a promising therapy alone and in combination therapy with PARPi in HR-deficient HGSOC. CX-5461 also has exciting potential as a treatment option for patients with relapsed HGSOC tumors that have high MYC activity and poor clinical outcome; these patients currently have very limited effective treatment options. This abstract is also being presented as Poster A71. Citation Format: Elaine Sanij, Katherine Hannan, Jiachen Xuan, Shunfei Yan, Jessica A. Ahern, Anna S. Trigos, Natalie Brajanovski, Jinbae Son, Keefe T. Chan, Olga Kondrashova, Elizabeth Lieschke, Matthew J. Wakefield, Sarah Ellis, Carleen Cullinane, Gretchen Poortinga, Kum Kum Khanna, Linda Mileshkin, Grant A. McArthur, John Soong, Els M. Berns, Ross D. Hannan, Clare L. Scott, Karen E. Sheppard, Richard B. Pearson. Inhibition of RNA polymerase I transcription activates targeted DNA damage response and enhances the efficacy of PARP inhibitors in high-grade serous ovarian cancer [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr PR13.