Publications by authors named "Mark O'connor"

PARP inhibitors have attracted considerable interest in drug discovery due to the clinical success of first-generation agents such as olaparib, niraparib, rucaparib, and talazoparib. Their success lies in their ability to trap PARP to DNA; however, first-generation PARP inhibitors were not strictly optimized for trapping nor for selectivity among the PARP enzyme family. Previously we described the discovery of the second-generation PARP inhibitor AZD5305, a selective PARP1-DNA trapper.

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Background: Adavosertib is a first-in-class, selective small-molecule inhibitor of Wee1. Olaparib is an inhibitor of poly(ADP-ribose) polymerase (PARP). Preclinical data suggest that adavosertib enhances the antitumor effect of PARP inhibitors.

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Background: Poly (ADP-ribose) polymerase 1 and 2 (PARP1/2) inhibitors (PARPi) are targeted therapies approved for homologous recombination repair (HRR)-deficient breast, ovarian, pancreatic, and prostate cancers. Since inhibition of PARP1 is sufficient to cause synthetic lethality in tumors with homologous recombination deficiency (HRD), PARP1 selective inhibitors such as saruparib (AZD5305) are being developed. It is expected that selective PARP1 inhibition leads to a safer profile that facilitates its combination with other DNA damage repair inhibitors.

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Background: Addressing Patient Reported Outcomes (PROs) is essential for patient-centred care, shared decision making and improved health outcomes. Value-based health care systems in New South Wales (NSW) have a growing focus on collecting and using PROs that matter most to patients to improve their healthcare outcomes. Developing oral health patient reported outcomes measures (OH-PROM) is a first step towards value-based oral health care.

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Diffuse large B-cell lymphoma (DLBCL) is the most common malignancy that develops in patients with ataxia-telangiectasia, a cancer-predisposing inherited syndrome characterized by inactivating germline ATM mutations. ATM is also frequently mutated in sporadic DLBCL. To investigate lymphomagenic mechanisms and lymphoma-specific dependencies underlying defective ATM, we applied RNA sequencing and genome-scale loss-of-function clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 screens to systematically interrogate B-cell lymphomas arising in a novel murine model (Atm-/-nu-/-) with constitutional Atm loss, thymic aplasia but residual T-cell populations.

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Unlabelled: Oncology drug combinations can improve therapeutic responses and increase treatment options for patients. The number of possible combinations is vast and responses can be context-specific. Systematic screens can identify clinically relevant, actionable combinations in defined patient subtypes.

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Poly(ADP-ribose) polymerase (PARP) inhibitors (PARPi) represent the first medicines based on the targeting of the DNA damage response (DDR). PARPi have become standard of care for first-line maintenance treatment in ovarian cancer and have also been approved in other cancer indications including breast, pancreatic and prostate. Despite their efficacy, resistance to PARPi has been reported clinically and represents a growing patient population with unmet clinical need.

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Purpose: We evaluated the properties and activity of AZD9574, a blood-brain barrier (BBB) penetrant selective inhibitor of PARP1, and assessed its efficacy and safety alone and in combination with temozolomide (TMZ) in preclinical models.

Experimental Design: AZD9574 was interrogated in vitro for selectivity, PARylation inhibition, PARP-DNA trapping, the ability to cross the BBB, and the potential to inhibit cancer cell proliferation. In vivo efficacy was determined using subcutaneous as well as intracranial mouse xenograft models.

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Objective: People with diabetes mellitus, particularly those with limited access to longitudinal care, frequently present to the emergency department (ED). Continuous glucose monitoring (CGM) has been shown to improve outcomes in ambulatory settings, so we hypothesized that it would be beneficial if initiated upon ED discharge.

Methods: We randomized adults with diabetes who were seen in the ED for hypo- or hyperglycemia to either 14 days of flash CGM or care coordination alone.

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an epigenetic tumor suppressor, is the most common gene mutation in clear-cell ovarian cancers (CCOCs). CCOCs are often resistant to standard chemotherapy and lack effective therapies. We hypothesized that loss would increase CCOC cell dependency on chromatin remodeling and DNA repair pathways for survival.

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Novel therapeutic strategies that can effectively combine with immunotherapies are needed in the treatment of triple-negative breast cancer (TNBC). We demonstrate that combined PARP and WEE1 inhibition are synergistic in controlling tumour growth in BRCA1/2 wild-type TNBC preclinical models. The PARP inhibitor (PARPi) olaparib combined with the WEE1 inhibitor (WEE1i) adavosertib triggered increases in anti-tumour immune responses, including STING pathway activation.

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Background: This study assessed safety and feasibility of a novel extravascular implantable cardioverter defibrillator (ICD) lead when inserted anteriorly through a rib space and connected to various commercially available ICD pulse generators (PGs) placed in either a left mid-axillary or left pectoral pocket. Currently available or investigational, extravascular-ICDs include a subcutaneous or subxiphoid lead connected to customized extravascular-ICD PGs.

Methods: This novel extravascular-ICD (AtaCor Medical Inc, San Clemente, CA) employs a unique intercostal implant technique and is designed to function with commercial DF-4 ICD PGs.

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The PSMC3IP-MND1 heterodimer promotes meiotic D loop formation before DNA strand exchange. In genome-scale CRISPR-Cas9 mutagenesis and interference screens in mitotic cells, depletion of PSMC3IP or MND1 causes sensitivity to poly (ADP-Ribose) polymerase inhibitors (PARPi) used in cancer treatment. PSMC3IP or MND1 depletion also causes ionizing radiation sensitivity.

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Unlabelled: PARP inhibitors (PARPi) are currently indicated for the treatment of ovarian, breast, pancreatic, and prostate cancers harboring mutations in the tumor suppressor genes or . In the case of ovarian and prostate cancers, their classification as homologous recombination repair (HRR) deficient (HRD) or mutated also makes PARPi an available treatment option beyond or mutational status. However, identification of the most relevant genetic alterations driving the HRD phenotype has proven difficult and recent data have shown that other genetic alterations not affecting HRR are also capable of driving PARPi responses.

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Purpose: We hypothesized that inhibition and trapping of PARP1 alone would be sufficient to achieve antitumor activity. In particular, we aimed to achieve selectivity over PARP2, which has been shown to play a role in the survival of hematopoietic/stem progenitor cells in animal models. We developed AZD5305 with the aim of achieving improved clinical efficacy and wider therapeutic window.

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Article Synopsis
  • PARP inhibitors (PARPi) are effective for treating HRR-deficient tumors but face resistance; combining them with WEE1 inhibitors (WEE1i) can enhance antitumor effects by increasing replication stress.
  • Research shows different resistance mechanisms for PARPi, with WEE1i and ATR inhibitors (ATRi) providing distinct strategies to overcome these challenges in breast and ovarian cancer models.
  • Targeting replication stress may help treat even tumors that aren't HRR-deficient, with ongoing clinical trials testing PARPi alongside WEE1i and ATRi to improve outcomes.
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Background: Type 2 diabetes (T2D) is a worldwide scourge caused by both genetic and environmental risk factors that disproportionately afflicts communities of color. Leveraging existing large-scale genome-wide association studies (GWAS), polygenic risk scores (PRS) have shown promise to complement established clinical risk factors and intervention paradigms, and improve early diagnosis and prevention of T2D. However, to date, T2D PRS have been most widely developed and validated in individuals of European descent.

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Article Synopsis
  • PARP inhibitors, like olaparib, cause cell death in cancer cells with BRCA1/2 mutations by leading to DNA damage, which can also trigger an immune response against tumors.
  • When olaparib is combined with immune checkpoint blockade (ICB), it showed enhanced and longer-lasting anti-tumor effects compared to using either treatment alone in a specific mouse model.
  • The combination therapy not only boosted the number of active immune cells but also activated important immune signaling pathways, and these findings were supported by results from human patient samples, indicating a promising direction for enhancing cancer treatment strategies.
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Unlabelled: PARP inhibitors (PARPi) are approved drugs for platinum-sensitive, high-grade serous ovarian cancer (HGSOC) and for breast, prostate, and pancreatic cancers (PaC) harboring genetic alterations impairing homologous recombination repair (HRR). Detection of nuclear RAD51 foci in tumor cells is a marker of HRR functionality, and we previously established a test to detect RAD51 nuclear foci. Here, we aimed to validate the RAD51 score cut off and compare the performance of this test to other HRR deficiency (HRD) detection methods.

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Unlabelled: AZD6738 (ceralasertib) is a potent and selective orally bioavailable inhibitor of ataxia telangiectasia and Rad3-related (ATR) kinase. ATR is activated in response to stalled DNA replication forks to promote G2-M cell-cycle checkpoints and fork restart. Here, we found AZD6738 modulated CHK1 phosphorylation and induced ATM-dependent signaling (pRAD50) and the DNA damage marker γH2AX.

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Poly(ADP-ribose) polymerase (PARP) inhibitors have transformed the therapeutic landscape for advanced ovarian cancer and expanded treatment options for other tumor types, including breast, pancreas, and prostate cancer. Yet, despite the success of PARP inhibitors in our current therapeutic armamentarium, not all patients benefit because of primary resistance, whereas different acquired resistance mechanisms can lead to disease progression on therapy. In addition, the toxicity profile of PARP inhibitors, primarily myelosuppression, has led to adverse events in a proportion of patients as monotherapy, and has limited the use of PARP inhibitors for certain rational combination strategies, such as chemotherapy and targeted therapy regimens.

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Article Synopsis
  • Traditional GWAS typically focus on additive allelic effects, which may overlook important recessive gene variants related to complex traits like type 2 diabetes.
  • This study conducted the largest GWAS meta-analysis using a recessive model, including over 33,000 diabetes cases and nearly 280,000 controls, identifying 51 associated loci—five of which were previously undetected.
  • Notably, one low-frequency variant significantly increased diabetes risk in homozygous carriers and was linked to changes in cholesterol levels and triglycerides, highlighting the importance of using recessive models in genetic research.
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Poly-ADP-ribose-polymerase (PARP) inhibitors have achieved regulatory approval in oncology for homologous recombination repair deficient tumors including BRCA mutation. However, some have failed in combination with first-line chemotherapies, usually due to overlapping hematological toxicities. Currently approved PARP inhibitors lack selectivity for PARP1 over PARP2 and some other 16 PARP family members, and we hypothesized that this could contribute to toxicity.

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Microphysiological in vitro systems are platforms for preclinical evaluation of drug effects and significant advances have been made in recent years. However, existing microfluidic devices are not yet able to deliver compounds to cell models in a way that reproduces the real physiological drug exposure. Here, we introduce a novel tumour-on-chip microfluidic system that mimics the pharmacokinetic profile of compounds on 3D tumour spheroids to evaluate their response to the treatments.

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