The potential of the PARP-1 inhibitor, AGO14699, in human cancers defective in homologous recombination DNA repair

PhD ThesisThe aims of this study were to undertake the first comprehensive in vitro, in vivo and clinical investigation into the effects of the PARP-1 inhibitor, AG014699, in human cancers defective in homologous recombination (HR) DNA double strand break (DSB) repair. HR deficient cells were 9-fold more sensitive to AG014699 than HR proficient cells (mean LC50 = 3.26 μM vs. 29.68; P 95% and induced DNA DSBs in all 11 cell lines studied. Evidence of HR (by Rad51 foci) was observed only in cells with functional BRCA1/2. A prolonged schedule of AG014699 (10 mg/kg daily for five days of a seven-day cycle for six cycles) more effectively delayed the growth of BRCA2 mutated xenografts than a ten day AG014699 schedule (tumour growth delay (TGD) = 27.5 vs. 12.5 days; P = 0.02). AG014699 significantly delayed UACC3199 tumour growth compared to untreated controls (mean time to relative tumour volume 5 = 35.8 vs. 25.2 days; P = 0.05); confirming in vitro findings that BRCA1 methylated cancer cells are sensitive to PARP inhibition. Clinical trial data from 38 patients demonstrated that AG014699 is non-toxic and efficacious with a clinical benefit rate of 34%. Higher baseline PARP-1 activity was associated with response to AG014699. The major findings of these studies are: the confirmation of the selective cytotoxicity of PARP inhibitors in BRCA mutated cancers; the results in UACC3199 cells which suggest that cancers with other HR defects could benefit from single agent PARP inhibitors, and finally the concept that length of exposure to (not just degree of) PARP inhibition is important for single agent anti-tumour activity. Furthermore, these data have formed the basis for a major amendment to the clinical trial; the result of which is eagerly awaited.Cancer Research U

Does the Tripartite Influence Model of Body Image and Eating Pathology Function Similarly Across Racial/Ethnic Groups of White, Black, Latina, and Asian Women?

The tripartite influence model suggests that appearance pressures from family, peers, and the media contribute to thin-ideal internalization, which leads to increased body dissatisfaction and subsequent eating disorder pathology. The tripartite influence model was initially developed and tested among primarily White samples, and emerging research suggests racial/ethnic differences in mean levels of particular model constructs. Consequently, the model\u27s appropriateness for understanding eating disorder risk in racial/ethnic minorities warrants investigation to determine its usefulness in explicating eating disorder risk in diverse populations. Participants in the current study were White (n = 1167), Black (n = 212), Latina (n = 203), and Asian (n = 176) women from five geographically disparate college campuses in the United States. Participants completed the Sociocultural Attitudes Towards Appearance Questionnaire-4, the Multidimensional Body-Self Relations Questionnaire - Appearance Evaluation Subscale, and the Eating Disorder Examination-Questionnaire. Analysis of variance was used to compare mean levels of each construct across racial/ethnic groups. Multigroup structural equation modeling was used to assess the appropriateness of the tripartite influence model for each racial/ethnic group, and to examine differences in the strength of the model pathways across groups. There were significant mean level differences across groups for most model constructs. However, results indicated similar model fit across racial/ethnic groups, with few differences in the strength of model pathways. Findings suggest that although some groups report lower levels of proposed risk factors, the sociocultural risk processes for eating pathology identified through the tripartite influence model are similar across racial/ethnic groups of young adult women. Such information can be used to inform culturally-sensitive interventions

A phase I pharmacokinetic and pharmacodynamic study of the oral mitogen-activated protein kinase kinase (MEK) inhibitor, WX-554, in patients with advanced solid tumours

Purpose: We performed a multi-centre phase I study to assess the safety, pharmacokinetics (PK) and pharmacodynamics (PD) of the orally available small molecule mitogen-activated protein kinase kinase (MEK) 1/2 inhibitor, WX-554, and to determine the optimal biological dose for subsequent trials. Experimental design: Patients with treatment-refractory, advanced solid tumours, with adequate performance status and organ function were recruited to a dose-escalation study in a standard 3 + 3 design. The starting dose was 25 mg orally once weekly with toxicity, PK and PD guided dose-escalation with potential to explore alternative schedules. Results: Forty-one patients with advanced solid tumours refractory to standard therapies and with adequate organ function were recruited in eight cohorts up to doses of 150 mg once weekly and 75 mg twice weekly. No dose-limiting toxicities were observed during the study, and a maximum tolerated dose (MTD) was not established. The highest dose cohorts demonstrated sustained inhibition of extracellular signal-regulated kinase (ERK) phosphorylation in peripheral blood mononuclear cells following ex-vivo phorbol 12-myristate 13-acetate stimulation. There was a decrease of 70 ± 26% in mean phosphorylated (p)ERK in C1 day 8 tumour biopsies when compared with pre-treatment tumour levels in the 75 mg twice a week cohort. Prolonged stable disease (>6 months) was seen in two patients, one with cervical cancer and one with ampullary carcinoma. Conclusions: WX-554 was well tolerated, and an optimal biological dose was established for further investigation in either a once or twice weekly regimens. The recommended phase 2 dose is 75 mg twice weekly

Food Insecurity During the First Year of COVID-19: Employment and Sociodemographic Factors Among Participants in the CHASING COVID Cohort Study

Objective: While much has been reported about the impact of the COVID-19 pandemic on food insecurity, longitudinal data and the variability experienced by people working in various industries are limited. This study aims to further characterize people experiencing food insecurity during the pandemic in terms of employment, sociodemographic characteristics, and degree of food insecurity. Methods: The study sample consisted of people enrolled in the Communities, Households and SARS-CoV-2 Epidemiology (CHASING) COVID Cohort Study from visit 1 (April–July 2020) through visit 7 (May–June 2021). We created weights to account for participants with incomplete or missing data. We used descriptive statistics and logistic regression models to determine employment and sociodemographic correlates of food insecurity. We also examined patterns of food insecurity and use of food support programs. Results: Of 6740 participants, 39.6% (n = 2670) were food insecure. Non-Hispanic Black and Hispanic (vs non-Hispanic White) participants, participants in households with children (vs no children), and participants with lower (vs higher) income and education levels had higher odds of food insecurity. By industry, people employed in construction, leisure and hospitality, and trade, transportation, and utilities industries had the highest prevalence of both food insecurity and income loss. Among participants reporting food insecurity, 42.0% (1122 of 2670) were persistently food insecure (≥4 consecutive visits) and 43.9% (1172 of 2670) did not use any food support programs. Conclusions: The pandemic resulted in widespread food insecurity in our cohort, much of which was persistent. In addition to addressing sociodemographic disparities, future policies should focus on the needs of those working in industries vulnerable to economic disruption and ensure those experiencing food insecurity can access food support programs for which they are eligible

Race, ethnicity, community-level socioeconomic factors, and risk of COVID-19 in the United States and the United Kingdom

BACKGROUND: There is limited prior investigation of the combined influence of personal and community-level socioeconomic factors on racial/ethnic disparities in individual risk of coronavirus disease 2019 (COVID-19). METHODS: We performed a cross-sectional analysis nested within a prospective cohort of 2,102,364 participants from March 29, 2020 in the United States (US) and March 24, 2020 in the United Kingdom (UK) through December 02, 2020 via the COVID Symptom Study smartphone application. We examined the contribution of community-level deprivation using the Neighborhood Deprivation Index (NDI) and the Index of Multiple Deprivation (IMD) to observe racial/ethnic disparities in COVID-19 incidence. ClinicalTrials.gov registration: NCT04331509. FINDINGS: Compared with non-Hispanic White participants, the risk for a positive COVID-19 test was increased in the US for non-Hispanic Black (multivariable-adjusted odds ratio [OR], 1.32; 95% confidence interval [CI], 1.18–1.47) and Hispanic participants (OR, 1.42; 95% CI, 1.33–1.52) and in the UK for Black (OR, 1.17; 95% CI, 1.02–1.34), South Asian (OR, 1.39; 95% CI, 1.30–1.49), and Middle Eastern participants (OR, 1.38; 95% CI, 1.18–1.61). This elevated risk was associated with living in more deprived communities according to the NDI/IMD. After accounting for downstream mediators of COVID-19 risk, community-level deprivation still mediated 16.6% and 7.7% of the excess risk in Black compared to White participants in the US and the UK, respectively. INTERPRETATION: Our results illustrate the critical role of social determinants of health in the disproportionate COVID-19 risk experienced by racial and ethnic minorities. FUNDING: Please refer to the Funding section at the end of the article

Tisotumab vedotin in previously treated recurrent or metastatic cervical cancer

Purpose: Tissue factor (TF) is a potential target in cervical cancer as it is frequently highly expressed and associated with poor prognosis. Tisotumab vedotin, a first-in-class investigational antibody-drug conjugate targeting TF, has demonstrated encouraging activity in solid tumors. Here we report data from the cervical cancer cohort of innovaTV 201 phase 1/2 study (NCT02001623). Experimental Design: Patients with recurrent or metastatic cervical cancer received tisotumab vedotin 2.0 mg/kg every 3 weeks until progressive disease, unacceptable toxicity, or consent withdrawal. The primary objective was safety and tolerability. Secondary objectives included antitumor activity. Results: Of the 55 patients, 51% had received ≥2 prior lines of treatment in the recurrent or metastatic setting; 67% had prior bevacizumab+doublet chemotherapy. 51% of patients had squamous cell carcinoma. The most common grade 3/4 treatment-emergent adverse events (AEs) were anemia (11%), fatigue (9%), and vomiting (7%). No grade 5 treatment-related AEs occurred. Investigator-assessed confirmed objective response rate (ORR) was 24% (95% confidence interval [CI]: 13%−37%). Median duration of response (DOR) was 4.2 months (range: 1.0+−9.7); four patients responded for >8 months. The 6-month progression-free survival (PFS) rate was 29% (95% CI: 17%−43%). Independent review outcomes were comparable, with confirmed ORR of 22% (95% CI: 12%−35%), median DOR of 6.0 months (range: 1.0+−9.7), and 6-month PFS rate of 40% (95% CI: 24%−55%). TF expression was confirmed in most patients; no significant association with response was observed. Conclusions: Tisotumab vedotin demonstrated a manageable safety profile and encouraging antitumor activity in patients with previously treated recurrent or metastatic cervical cancer

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Tipping Growth Inhibition into Apoptosis by Combining Treatment with MDM2 and WIP1 Inhibitors in p53^WT Uterine Leiomyosarcoma

As there is no optimal therapeutic strategy defined for women with advanced or recurrent uLMS, there is an urgent need for the discovery of novel, targeted approaches. One such area of interest is the pharmacological inhibition of the MDM2-p53 interaction with small-molecular-weight MDM2 inhibitors. Growth inhibition and cytotoxic assays were used to evaluate uLMS cell line responses to MDM2 inhibitors as single agents and in combination, qRT-PCR to assess transcriptional changes and Caspase-Glo 3/7 assay to detect apoptosis. RG7388 and HDM201 are potent, selective antagonists of the MDM2-p53 interaction that can effectively stabilise and activate p53 in a dose-dependent manner. GSK2830371, a potent and selective WIP1 phosphatase inhibitor, was shown to significantly potentiate the growth inhibitory effects of RG7388 and HDM201, and significantly increase the mRNA expression of p53 transcriptional target genes in a p53WT cell line at a concentration that has no growth inhibitory effects as a single agent. RG7388, HDM201 and GSK2830371 failed to induce apoptosis as single agents; however, a combination treatment tipped cells into apoptosis from senescence. These data present the possibility of MDM2 and WIP1 inhibitor combinations as a potential treatment option for p53WT uLMS patients that warrants further investigation

Targeting the ATR-CHK1 Axis in Cancer Therapy

Targeting the DNA damage response (DDR) is a new therapeutic approach in cancer that shows great promise for tumour selectivity. Key components of the DDR are the ataxia telangiectasia mutated and Rad3 related (ATR) and checkpoint kinase 1 (CHK1) kinases. This review article describes the role of ATR and its major downstream target, CHK1, in the DDR and why cancer cells are particularly reliant on the ATR-CHK1 pathway, providing the rationale for targeting these kinases, and validation of this hypothesis by genetic manipulation. The recent development of specific inhibitors and preclinical data using these inhibitors not only as chemosensitisers and radiosensitisers but also as single agents to exploit specific pathologies of tumour cells is described. These potent and specific inhibitors have now entered clinical trial and early results are presented

The Role of ATR Inhibitors in Ovarian Cancer: Investigating Predictive Biomarkers of Response

Ataxia telangiectasia and Rad-3 related kinase (ATR) signals DNA lesions and replication stress (RS) to the S and G2/M checkpoints and DNA repair pathways making it a promising target to exploit the dysregulated DNA damage response in cancer. ATR inhibitors (ATRi) are under clinical investigation as monotherapy and in combination with other anticancer agents. Molecular determinants of sensitivity to ATRi are common in ovarian cancer, suggesting the therapeutic potential of ATRi. We investigated the cytotoxicity of the ATRi, VE-821, in a panel of human ovarian cancer cell lines. High grade serous (HGS) cell lines were significantly more sensitive to VE-821 than non-HGS (p ≤ 0.0001) but previously identified determinants of sensitivity (TP53, ATM and BRCA1) were not predictive. Only low RAD51 (p = 0.041), TopBP1 (p = 0.026) and APOBEC3B (p = 0.015) protein expression were associated with increased VE-821 sensitivity. HGS cells had increased levels of RS (pRPASer4/8 and γH2AX nuclear immunofluorescence), and elevated RS predicted sensitivity to VE-821 independently of the cell line subtype. These data suggest that functional assessment of RS biomarkers may be a better predictive biomarker of ATRi response than any single aberrant gene in ovarian cancer and potentially other cancers.Medicine, Faculty ofNon UBCMedicine, Department ofObstetrics and Gynaecology, Department ofReviewedFacultyResearche