Nesting chinstrap penguins accrue large quantities of sleep through seconds-long microsleeps

Microsleeps, the seconds-long interruptions of wakefulness by eye closure and sleep-related brain activity, are dangerous when driving and might be too short to provide the restorative functions of sleep. If microsleeps do fulfill sleep functions, then animals faced with a continuous need for vigilance might resort to this sleep strategy. We investigated electroencephalographically defined sleep in wild chinstrap penguins, at sea and while nesting in Antarctica, constantly exposed to an egg predator and aggression from other penguins. The penguins nodded off >10,000 times per day, engaging in bouts of bihemispheric and unihemispheric slow-wave sleep lasting on average only 4 seconds, but resulting in the accumulation of >11 hours of sleep for each hemisphere. The investment in microsleeps by successfully breeding penguins suggests that the benefits of sleep can accrue incrementally.

Abstract 2153: Cyclin E1 protein overexpression sensitizes ovarian cancer cells to ZN-c3, a novel, selective and oral bioavailable inhibitor of Wee1

CCNE1 gene amplification is associated with overexpression of Cyclin E1 protein and is an important oncogenic driver. CCNE1 amplification is common in high grade serous ovarian carcinomas (HGSOC) and is associated with platinum resistance and poor patient outcomes. Importantly, Cyclin E1 overexpression can also occur in the absence of gene amplification in ovarian cancer. Overexpression of Cyclin E1 increases CDK2 activity and accelerates entry into S phase of cell cycle, resulting in replication stress and rendering cells more dependent on DNA repair. WEE1 participates in the DNA damage response by controlling essential checkpoints of the cell cycle, preventing cells from entering mitosis and allowing for DNA repair before cell cycle progression. Thus, we hypothesize that ovarian cancers overexpressing Cyclin E1, either via CCNE1 gene amplification or through other independent mechanisms, are more sensitive to WEE1 inhibition. Here, we tested this hypothesis in a range of preclinical cancer models using azenosertib, a novel, selective, and orally bioavailable WEE1 inhibitor currently in clinical development. Ovarian cancer cell lines overexpressing Cyclin E1 protein (Cyclin E1high) were more sensitive to azenosertib than ovarian cancer cell lines with lower levels of Cyclin E1 protein (Cyclin E1low) inducing significant cytotoxic effects (GRmax < -0.5). In Cyclin E1low ovarian cancer cell lines, overexpression of Cyclin E1 increased sensitivity to azenosertib. In contrast, silencing of CDK2 in Cyclin E1high cells reduced sensitivity to azenosertib. In vivo, higher levels of baseline expression of Cyclin E1 in tumor cells were associated with better response to azenosertib, with tumor growth inhibition (TGI) ranging from 51.5% in a Cyclin E1low SKOV3 model to 88% in a Cyclin E1high OVCAR3 model. Azenosertib synergized with chemotherapy agents in multiple ovarian cancer models. In vitro, we report that Cyclin E1high cancer cells were more sensitive to the combination of azenosertib and chemotherapeutics than Cyclin E1low cancer cells. In vivo, the synergy between azenosertib and paclitaxel was stronger in Cyclin E1high OVCAR3 model (46% reduction of initial tumor volume/104% TGI) than Cyclin E1low A2780 model (85% TGI). Taken together, these data suggest that Cyclin E1 overexpression via gene amplification or independent mechanisms sensitize ovarian cancer cells to azenosertib alone or in combination with chemotherapy. This observation supports the use of Cyclin E1 expression to enrich for azenosertib responders in ovarian cancer and possibly other tumor types. Two subsets of Cyclin E1-driven platinum resistant ovarian cancer patients, as defined by gene amplification or protein overexpression, are being enrolled in an azenosertib monotherapy trial.

Citation Format: Jianhui Ma, Wen Liu, Heekyung Chung, Hooman Izadi, Petrus DeJong, Olivier Harismendy, Jia li, Fernando Doñate, Ahmed Samatar, Mark Lackner, Laure Escoubet, Kevin Bunker, Daehwan Kim, Nathan Jameson, Tugba Yildiran Ozmen, Kangjin Jeong, Dong Zhang, Wen-An Pan, Gordon Mills. Cyclin E1 protein overexpression sensitizes ovarian cancer cells to ZN-c3, a novel, selective and oral bioavailable inhibitor of Wee1 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2153.

Cluster Analysis of DSC MRI, Dynamic Contrast-Enhanced MRI, and DWI Parameters Associated with Prognosis in Patients with Glioblastoma after Removal of the Contrast-Enhancing Component: A Preliminary Study

BACKGROUND AND PURPOSE

No report has been published on the use of DSC MR imaging, DCE MR imaging, and DWI parameters in combination to create a prognostic prediction model in glioblastoma patients. The aim of this study was to develop a machine learning-based model to find preoperative multiparametric MR imaging parameters associated with prognosis in patients with glioblastoma. Normalized CBV, volume transfer constant, and ADC of the nonenhancing T2 high-signal-intensity lesions were evaluated using K-means clustering.

MATERIALS AND METHODS

A total of 142 patients with glioblastoma who underwent preoperative MR imaging and total resection were included in this retrospective study. From the normalized CBV, volume transfer constant, and ADC maps, the parametric data were sorted using the K-means clustering method. Patients were divided into training and test sets (ratio, 1:1), and the optimal number of clusters was determined using receiver operating characteristic analysis. Kaplan-Meier survival analysis and log-rank tests were performed to identify potential parametric predictors. A multivariate Cox proportional hazard model was conducted to adjust for clinical predictors.

RESULTS

The nonenhancing T2 high-signal-intensity lesions were divided into 6 clusters. The cluster (class 4) with the relatively low normalized CBV and volume transfer constant value and the lowest ADC values was most associated with predicting glioblastoma prognosis. The optimal cutoff of the class 4 volume fraction of nonenhancing T2 high-signal-intensity lesions predicting 1-year progression-free survival was 9.70%, below which the cutoff was associated with longer progression-free survival. Two Kaplan-Meier curves based on the cutoff value showed a statistically significant difference (P = .037). When we adjusted for all clinical predictors, the cluster with the relatively low normalized CBV and volume transfer constant values and the lowest ADC value was an independent prognostic marker (hazard ratio, 3.04; P = .048). The multivariate Cox proportional hazard model showed a concordance index of 0.699 for progression-free survival.

CONCLUSIONS

Our model showed that nonenhancing T2 high-signal-intensity lesions with the relatively low normalized CBV, low volume transfer constant values, and the lowest ADC values could serve as useful prognostic imaging markers for predicting survival outcomes in patients with glioblastoma.

Paid Sick Leave and Sickness Benefits for employees’ economic and job security: A Scoping Review

 

In health emergencies, such as in the COVID-19 pandemic, the need to expand or introduce the Paid sick leave(PSL) and Sickness benefits(SB) increases. They are key components of the universal health coverage(UHC) and active labor market policies(ALMPs) that enable workers to take care of their health and guarantee return-to-work after recovery. This study examines effects those policies in achieving economic stability and job security of covered workers through a scoping review. Studies were selected using the search terms ‘paid sick leave', ‘sickness benefits', ‘paid sick day', and ‘earned sick leave’ in PubMed and Web of Science. Our search conducted on 6th April 2021 yielded 1,030 articles, of which 22 articles were included in the review. All articles were analyzed by the 4 sub-groups(employees, families, employers, and government) and we investigated indicators of socio-economic impacts on their lives. Articles are largely PSL(90.9%)-focused. PSL guarantees not only workers’ job security by securing employment agreement, but also their income security by promising part of wages enough to afford healthcare and living expenses during the medical treatment and recovery. Additionally, PSL attenuates employers’ financial risk, as it reduces presenteeism while increasing the return-to-work rate. Moreover, PSL and SB reduce the total healthcare and social security expenditures of the government. To sum up, PSL and SB guarantee health and labor rights by ensuring income and job security to employees while assuring financial stability to both employers, and the government. However, as the previous studies paid less attention on the equity of these impacts at the system levels, future research should more focus on the dimension.

Key messages

• PSL and SB guarantee health and labour rights by ensuring income and job security for employees, while assuring financial stability for both employers and the government.

• The previous studies that examined the effects of PSL and SB paid less attention on the equity of ensuring income and employment security, therefore future studies should focus more on this dimension.

The paid sick leave and sickness benefits for universal health coverage: a scoping review

Background

The countries with paid sick leave (PSL) and sickness benefits (SB) mostly provide the benefit coverage to specific categories of workers, which results in health inequalities among employees in COVID-19. The PSL and SB are key factors to achieve universal health coverage (UHC) in that they protect access to healthcare and improve population health. This study attempted to investigate whether the policies helped achieve the UHC when they were expanded.

Methods

This review followed the scoping review protocol of PRISMA-ScR. On April 6, 2021, we extracted the literature using the keywords ‘paid sick leave', ‘sickness benefits', ‘paid sick day', and ‘earned sick leave’ from PubMed and Web of Science and added two studies through hand-search. All articles were written in English. We did not limit the publication date.

Results

Forty-four selected studies were based in four single countries and the European Union. Most of the studies were published after 2010 (84.1%) and were conducted as cross-sectional (72.7%) studies. Not only workers who use PSL and SB but also children whose parents use PSL and SB increased their use of healthcare services and getting flu shots. Also, using PSL and SB decreased their unmet healthcare needs and emergency use. The various health status factors, such as infectious disease incidence, mortality, and presenteeism, also decreased.

Conclusions

The provisions of PSL and SB offer individual and public health benefits by allowing employees and their families to use healthcare services. Group of employees, we can expect similar public health impacts on newly covered groups, thus contributing to achieving the UHC. Since more than 90% of articles are published from the United States, future studies need to evaluate the outcomes of health effects in various European or Asian countries.

Key messages

• The provision of PSL and SB positively affects employees and their families by allowing them to use healthcare services.

• The expansion of PSL and SB contributes to the UHC by guaranteeing indirect medical costs that enable universal access to essential healthcare services.

A Sick Benefit Scheme Reduces Unmet Healthcare Needs: An Natural Experiment in Seoul

 

South Korea experiences four times more unmet healthcare needs than OECD countries (11.6% and 2.6% respectively). Unmet healthcare needs are caused by the double burden of direct and indirect costs including income loss, and OECD countries operate a sickness benefit scheme to resolve sudden loss of pay. Seoul introduced the first sickness benefit system, Seoul-Type Paid Sick Leave Support (hereinafter Seoul Sick Leave), for self-employed national healthcare insurance subscribers to reduce the rate of unmet healthcare needs. By comparing the amount of increasing medical expenses between the beneficiary and non-beneficiary before (2018) and after (2019-2020) the introduction of the system, the study was intended to confirm the reduced unmet healthcare needs. This study used data from the National Health Information Database (NHID) and the difference in differences (DID) analytic framework. 96 and 121 patients were included in benefit and non-benefit cohorts, respectively. As a result, the beneficiary group’s expenses were smaller than those of the non-beneficiary group (coef.=-1.24, p = 0.026). However, the beneficiary group had a greater amount of increase in hospitalization expenses before and after the introduction than the non-beneficiary group did (coef.=1.66, p = 0.005). Our finding showed that the Seoul Sick Leave helped the precarious workers as they were able to use inpatient services when they needed. If it is to be scaled up to the national level, it should be applied all people to enhance universal health insurance in Korea.

Key messages

• Identified the effectiveness of the first sickness benefit system as it helped the precarious workers as they were able to use inpatient services when they needed.

• By financially supporting them, the Seoul Sick Leave support can achieve health promotion through early detection and treatment.

Inequalities in adverse birth outcomes and survival in early childhood: birth cohort in South Korea

Background

Adverse birth outcomes (ABOs) are considered the most common factor of deaths in early childhood. Inequalities in child mortality occur due to interactions between intrinsic and socio-environmental factors related to socioeconomic disadvantage. There are, however, few studies investigating the impact of ABOs on mortality in terms of parental SEP.

Methods

Using the Under-5 Infant Birth-Death Cohort Data in Korea, a pooled retrospective birth cohort of all children born in 2012-2014 was built (N = 1,356,584). We analyzed neonatal, post-neonatal, and childhood mortality by ABOs and with the interaction of parental SEP using the Cox proportional hazard regression model for survival analyses. We further stratified the analysis both by parental SEP and child age. Multiple logistic regression was performed to confirm the social inequalities in ABO itself.

Results

After adjusting for covariates, children born with ABOs presented higher risk of mortality for all periods. For post-neonatal period, lower maternal education showed significant interaction effect with LBW (HR = 0.57; 95% CI = [0.39-0.85]), PTB (HR = 0.53; 95% CI = [0.33-0.86]), LBW & PTB ([HR = 0.67; 95% CI = [0.54-0.83]) while lower paternal education (HR = 0.67; 95% CI = [0.54-0.82]) and maternal unemployment (HR = 0.80; 95% CI = [0.63-0.99]) showed significance for babies with LBW & PTB. However, stratification analyses suggested that the impact of ABOs on mortality was greater for children born to lower parental SEP in neonatal period. Meanwhile apparent social inequalities in ABOs were suggested from regression analyses.

Conclusions

We confirmed social inequalities in the incidence of ABOs as well as mortalities from ABOs. However, the difference in mortality between babies with and without ABOs was greater for advantaged children. Policies to reduce the mortality of children with ABOs as well as those of healthy children among socioeconomically disadvantaged families are required.

Key messages

• Social inequalities in mortality from ABOs were apparent especially in the neonatal period while the incidence of ABOs itself was greater among children from disadvantaged families.

• Disadvantaged children are more likely to die not only from ABOs but also from other socio-environmental determinants, especially in the post-neonatal period than their counterparts.

Myocardial extracellular space expansion is related to burden of premature ventricular contractions in patients with hypertrophic cardiomyopathy without non-sustained ventricular tachycardia

Funding Acknowledgements

Type of funding sources: None.

Background

Current guidelines suggest the presence of non-sustained ventricular tachycardia (NSVT) as a risk factor of sudden cardiac death in patients with hypertrophic cardiomyopathy (HCM). However, high burden of premature ventricular contraction (PVC) may reflect myocardial fibrosis although the absence of NSVT.

Purpose

We investigated the association between PVC burden and myocardial extracellular space expansion in HCM patients without NSVT.

Methods

Of the 212 patients prospectively enrolled to the HCM registry of genetics, 84 patients were evaluated with both cardiac magnetic resonance and 24hr holter. Among them, 71 patients (58 males, mean age: 71 ± 13 years) have not been diagnosed with NSVT.

Results

Patients with NSVT (n = 13) showed more impaired LA functional indices and higher myocardial fibrosis burden compared with patients without NSVT (n = 71). Among patients who have not been diagnosed with NSVT, patients with late gadolinium enhancement (LGE, n = 46) had a higher total beats (109 ± 332 vs. 7 ± 13 beats per a day, p = 0.003) and burden (0.114 ± 0.225 vs. 0.008 ± 0.014 %, p = 0.003) of PVC during 24-hour compared with patients without LGE (n = 25). %LGE was correlated with total beats of PVC (r = 0.358, p = 0.002) and PVC burden (r = 0.377, p = 0.001). ECV also correlated with total beats of PVC (r = 0.387, p = 0.001) and PVC burden (r = 0.401, p = 0.001). The optimal cutoff value for PVC number was 45 (37.0% of sensitivity and 100% of specificity) with 0.733 of the area under the ROC curve (p < 0.001). Pathogenic or likely pathogenic sarcomere mutation was higher in NSVT group than no NSVT group (p < 0.05), and had a higher tendency in higher PVC burden group (0.05 < p < 0.1) than lower PVC burden group.

Conclusions

Total beats and burden of PVC are significantly related to increase in myocardial fibrosis in HCM patients without NSVT.

Abstract Figure. Mechanism of ventricular arrhythmia

Abstract 6401: SM08502, a novel, small-molecule CDC-like kinase (CLK) inhibitor, demonstrates strong antitumor effects and Wnt and cyclin D-CDK4/6-RB pathway inhibition in hormone-receptor-positive (HR+) breast cancer models

Dysregulation of the cyclin D-CDK4/6-RB signaling axis is implicated in HR+ breast cancer (BC). While CDK4/6 inhibitors such as palbociclib (Palbo) have shown efficacy in this cancer type, overcoming resistance to these agents is an unmet need for patients. SM08502 has demonstrated strong antitumor activity in several preclinical cancer models and has been shown to inhibit the Wnt pathway via disruption of alternative splicing. We examined SM08502 activity in preclinical models of CDK4/6 inhibitor-sensitive and -resistant HR+, HER2-negative (HER2-) BC. In vitro, SM08502 inhibited serine/arginine-rich splicing factor 6 (SRSF6) phosphorylation and suppressed Wnt-related gene and protein expression (e.g., DVL2, LRP5, TCF7L2) in MCF7 and T47D cells (HR+, HER2-). To test SM08502 activity on CDK4/6 inhibitor-resistant HR+, HER2- BC, we generated Palbo-resistant (Palbo-R) T47D cells. Resistance was confirmed by reduced RB and ER-α expression and increased cyclin E1 expression in Palbo-R vs. parental cells. RB phosphorylation was not inhibited upon Palbo (1 μM) treatment in Palbo-R vs. parental cells. SM08502 impaired parental (EC50=0.22 µM) and Palbo-R (EC50=0.41 µM) T47D cell proliferation, while CDK4/6 inhibitors (Palbo, abemaciclib, ribociclib) were only effective on parental cells. Compared to DMSO, SM08502 induced apoptosis in parental and Palbo-R cells as measured by caspase 3/7 activation, PARP cleavage, and MCL-1 expression. Compared to DMSO and CDK4/6 inhibitors, SM08502 (1 μM) inhibited RB phosphorylation and expression of ER-α, AR, and cyclins D1 and E in parental and Palbo-R cells, demonstrating potent activity against CDK4/6 pathway activation. In vivo antitumor effects and tolerability of oral SM08502 (25mg/kg QD) alone or combined with fulvestrant (F) ± Palbo in a CDK4/6 inhibitor-sensitive model were assessed in mice bearing orthotopic MCF7 xenografts (n=8/group). Compared to vehicle, SM08502 induced greater tumor growth inhibition (TGI) than F (75 mg/kg BIW) or Palbo (50 mg/kg QD) (70% [P<0.001], 43% [P=0.34], 48% [P=0.16], respectively). SM08502 plus F or Palbo and triplet combination induced strong TGI (75%, 78%, 86%, respectively, P<0.001) and tumor regression (6/8, 7/7, 8/8, respectively). SM08502 was reduced to 12.5 mg/kg at D12 in the triplet due to poor tolerability. In 2 patient-derived xenograft models of HR+ BC, strong TGI was observed with SM08502 (92% [P<0.001] and 71% [P<0.05]) vs. vehicle. Mean bodyweight loss from baseline (tolerability assessment) was <15% in all groups over all study periods. Together, these data suggest that SM08502 has potential antitumor activity in HR+ BC and may provide clinical benefit as a single agent or combined with standard therapy. A Phase 1 study of SM08502 in subjects with advanced solid tumors is ongoing (NCT03355066).

Citation Format: Heekyung Chung, Lauren Sitts, Chu-Chiao Wu, Brian Eastman, Chi Ching Mak, Sunil KC, Josh Stewart, Carine Bossard, Timothy J. Phalen, Steven Cha. SM08502, a novel, small-molecule CDC-like kinase (CLK) inhibitor, demonstrates strong antitumor effects and Wnt and cyclin D-CDK4/6-RB pathway inhibition in hormone-receptor-positive (HR+) breast cancer models [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 6401.

Abstract 3521: Transcriptome analysis of TCGA prostate cancer samples identifies an association of poorer survival and aggressive disease biology with CDC-like kinase (CLK) expression and spliceosome regulation

In prostate cancer, alternative splicing of mRNA and spliceosome activity are implicated in several areas of disease pathogenesis. This is exemplified by the strong association of androgen receptor splice variants with treatment resistance and poor clinical outcome in castration-resistant disease. Therefore, pharmacologic targeting of spliceosome-regulating proteins such as CLKs and serine/arginine-rich splicing factors (SRSFs) represents a novel treatment approach for prostate cancer. To evaluate the therapeutic potential of inhibiting CLK activity in prostate cancer, the association between splicing-related gene expression and survival was investigated in The Cancer Genome Atlas Prostate Adenocarcinoma (TCGA-PRAD) data collection (N=495). Survival analysis of RNA-seq data assessed 17,879 genes to measure their association with progression-free interval (PFI). Using transcript per million as the metric for normalized gene expression, age-adjusted Cox proportional hazards regression models were performed for each gene (R v3.6.0, coxph v2.43-3). A total of 3,145 genes significantly correlated with worse prognosis (P-adj<0.10, Cox coefficient >0). CLK1 (P-adj=0.0218, HR=1.5939), CLK2 (P-adj=0.001298, HR=2.1393), and SRSF2 (P-adj=0.00167, HR=3.2917) were found to be positively associated with poorer PFI, ranking 1202, 400, and 437, respectively. Reactome pathway analysis of the significant gene set showed that mRNA splicing and processing accounted for 5 of the 19 pathways that were strongly associated with poorer PFI. An additional pathway analysis (GSEA v.3.0, MSigDB v6.2) of tumors categorized by PTEN status to assess relationship with disease severity showed that mRNA splicing (P-adj=0.0243, NES=1.7714) was enriched in PTEN-null vs. PTEN-wt tumors. Other pathways of interest, including Wnt signaling (P-adj=0.0187, NES=1.846), cell cycle (P-adj=0.0124, NES=1.974), chromatin remodeling (P-adj=0.0135, NES=1.901), DNA damage repair (P-adj=0.013974, NES=1.8934), and PTEN regulation (P-adj=0.0230, NES=1.7861), were also enriched in PTEN-null tumors. Lastly, a survival analysis within all TCGA-PRAD patients showed that low CLK1 (P=0.03) and CLK2 (P=0.0004) expression, individually, were associated with a better prognosis vs. their high-expressing counterparts. Analysis of CLK3 and CLK4 expression did not reach statistical significance. Collectively, these findings revealed an association of spliceosome activity and CLK1/2 expression with aggressive disease biology in prostate cancer. A Phase 1 study of SM08502, a novel, small-molecule pan-CLK inhibitor, in subjects with advanced solid tumors is ongoing (NCT03355066). This analysis nominates prostate cancer as a tumor type worth further exploring for the clinical activity of SM08502.

Citation Format: Shawn Cho, Atish D. Choudhury, Catherine Fleener, Long Do, Carine Bossard, Heekyung Chung, Timothy J. Phalen, Steven Cha. Transcriptome analysis of TCGA prostate cancer samples identifies an association of poorer survival and aggressive disease biology with CDC-like kinase (CLK) expression and spliceosome regulation [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 3521.

Development of comparable algorithms to measure primary care indicators using administrative health data across three Canadian provinces

INTRODUCTION

Performance measurement has been recognized as key to transforming primary care (PC). Yet, performance reporting in PC lags behind even though high-performing PC is foundational to an effective and efficient health care system.

OBJECTIVES

We used administrative data from three Canadian provinces, British Columbia, Ontario and Nova Scotia, to: 1) identify and develop a core set of PC performance indicators using administrative data and 2) examine their ability to capture PC performance.

METHODS

Administrative data used included Physician Billings, Discharge Abstract Database, the National Ambulatory Care and Reporting System database, Census and Vital Statistics. Indicators were compiled based on a literature review of PC indicators previously developed with administrative data available in Canada (n=158). We engaged in iterative discussions to assess data conformity, completeness, and plausibility of results in all jurisdictions. Challenges to creating comparable algorithms were examined through content analysis and research team discussions, which included clinicians, analysts, and health services researchers familiar with PC.

RESULTS

Our final list included 21 PC performance indicators pertaining to 1) technical care (n=4), 2) continuity of care (n=6), and 3) health services utilization (n=11). Establishing comparable algorithms across provinces was possible though time intensive. A major challenge was inconsistent data elements. Ease of data access, and a deep understanding of the data and practice context, was essential for selecting the most appropriate data elements.

CONCLUSIONS

This project is unique in creating algorithms to measure PC performance across provinces. It was essential to balance internal validity of the indicators within a province and external validity across provinces. The intuitive desire of having the exact same coding across provinces was infeasible due to lack of standardized PC data. Rather, a context-tailored definition was developed for each jurisdiction. This work serves as an example for developing comparable PC performance indicators across different provincial/territorial jurisdictions.

Abstract A09: SM08502, a novel, small-molecule CDC-like kinase (CLK) inhibitor, demonstrates strong inhibition of the Wnt signaling pathway and antitumor effects in diverse ovarian cancer models

Aberrant activation of the Wnt signaling pathway is observed in ovarian cancer (OC) and is associated with chemoresistance, immune evasion, and poor prognosis. SM08502 is a novel, oral, small-molecule pan-CLK inhibitor that has been shown to potently inhibit the Wnt signaling pathway in preclinical colorectal cancer models. The purpose of these studies was to test the in vitro and in vivo activity of SM08502 in preclinical models of OC. The effect of SM08502 on cell viability was tested in 10 OC cell lines of various histotypes, including high-grade serous (HGS), serous, endometrioid, clear-cell, and teratocarcinoma lines in vitro. Cell proliferation was impaired in all cell lines by SM08502 regardless of histotype and mutation profile (average EC50=0.123 μM [0.034 – 0.275]). Relative to DMSO, SM08502 (1 μM) also potently inhibited Wnt-related gene expression (TCF7, DVL2, LRP5, and ERBB2), which correlated with inhibition of protein expression in HGSOC, endometrioid, and teratocarcinoma cell lines. Additionally, in cell lines derived from these histotypes, SM08502 strongly inhibited cyclin E1 gene and protein expression, the amplification/overexpression of which has been associated with treatment resistance and poor overall survival in HGSOC. In vivo antitumor effects and tolerability of oral SM08502 (6.25, 12.5 and 25 mg/kg QD for 15-22 days) were assessed in mice bearing OVCAR-3 (HGSOC; TP53mut), PA-1 (teratocarcinoma; N-Ras mut), and TOV-112D (endometrioid; CTNNB1mut) xenografts (n=5 mice per group). In OVCAR-3 xenografts, significant tumor growth inhibition (TGI) vs. vehicle occurred in mice treated with SM08502 12.5 mg/kg (66%, p<0.01) and 25 mg/kg (89%, p<0.001). SM08502 25 mg/kg also induced tumor regression in all mice. Similarly, in PA-1 xenografts, SM08502 induced TGI of 64% (p<0.01) at 12.5 mg/kg and 93% (p<0.01) with 4/5 tumors regressing at 25 mg/kg. SM08502 at 25 mg/kg also induced TGI of 64% (p<0.01) in TOV-112D xenografts. In addition, SM08502 (25 mg/kg QD) was assessed in 5 patient-derived xenograft (PDX) models of metastatic OC with double-hit TP53 and BRCA1/2 mutations (Crown Biosciences). Inhibition of tumor growth was observed in all tested PDXs (average TGI=61% [47-73], p<0.001). SM08502 was well tolerated in all xenograft models tested based on body weight measurements. In summary, SM08502 potently inhibited cell proliferation and expression of Wnt-related genes and cyclin E1 in OC cell lines. SM08502 also demonstrated strong in vivo antitumor effects, including tumor regressions, in different subtypes of OC xenografts and PDX models. These data suggest that SM08502 may provide clinical benefit for OC patients regardless of histotype, BRCA mutation status, or cyclin E1 expression. A phase 1 study assessing safety, tolerability, and pharmacokinetics of SM08502 in advanced solid tumors is ongoing (NCT03355066).

Citation Format: Heekyung Chung, Lauren Sitts, Emily Creger, Erica Liao, Brian Eastman, Chi-Ching Mak, K.C. Sunil, Betty Tam, Gail Bucci, Josh Stewart, Carine Bossard, Timothy Phalen, Steven Cha. SM08502, a novel, small-molecule CDC-like kinase (CLK) inhibitor, demonstrates strong inhibition of the Wnt signaling pathway and antitumor effects in diverse ovarian cancer models [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 A09.

Abstract P3-13-01: SM08502, a novel, small-molecule CDC-like kinase (CLK) inhibitor, demonstrates strong inhibition of the Wnt signaling pathway and antitumor effects as monotherapy and in combination with chemotherapy in triple-negative breast cancer (TNBC) models

Aberrant activation of the Wnt signaling pathway is associated with tumorigenesis, relapse/chemoresistance, and distance metastasis in TNBC. SM08502 is a novel, oral, small-molecule pan-CLK inhibitor that has been shown to potently inhibit the Wnt signaling pathway in several preclinical cancer models. The purpose of these studies was to examine the antitumor activity of SM08502 as monotherapy and in combination with standard chemotherapy in preclinical models of TNBC. The effect of SM08502 on cell proliferation was tested 13 BC cell lines, 7 of which were TNBC derived. Cell proliferation was strongly impaired by SM08502 across all lines (average EC50=0.170 µM [0.055-0.510]). SM08502 demonstrated similar potency between HR+ and TNBC cell lines with average EC50 values of 0.202 µM (0.058-0.510) and 0.142 µM (0.055-0.240), respectively. Relative to DMSO, SM08502 (1 μM) potently inhibited Wnt pathway-related gene and protein expression (TCF7, DVL2, LRP5, and ERBB2) in TNBC cell lines. Notably, SM08502 showed little inhibitory effect on cell proliferation in normal breast cells (Hs578Bst) compared with their paired TNBC cells (Hs578T) with an EC50 of 1.517 μM and 0.080 μM, respectively. Wnt pathway-related proteins were also overexpressed in Hs578T cells relative to Hs578Bst, and SM08502 (1 µM) strongly reduced their expression. In vivo antitumor effects and tolerability of oral SM08502 (25 mg/kg QD for 20 days) were assessed in mice bearing orthotopically implanted, luciferase-expressing, TNBC (MDA-MB231)-derived xenografts (n=5 mice per group). Significant tumor growth inhibition (TGI) vs. vehicle occurred in mice treated with SM08502 (80%, p<0.01). Metastasis was assessed by ex vivo imaging utilizing luciferase activity in bilateral lungs collected at study end. Luminescence was observed in 9/10 lungs from the vehicle-treated mice. In the SM08502-treated mice, only 3/10 lungs had measurable luminescence, suggesting that SM08502 reduced lung metastasis of TNBC tumors in this model. Additionally, SM08502 (12.5 and 25 mg/kg QD), gemcitabine (G)/Nab-paclitaxel (Nab-P) (75/30 mg/kg Q7D i.p.), and SM08502 combined with G/Nab-P were tested in MDA-MB231 xenografts. SM08502 (12.5 and 25 mg/kg) and G/Nab-P alone induced strong TGI vs. vehicle (81, 86, and 91%, respectively; p<0.0001), although no tumor regressions occurred. SM08502 (12.5 and 25 mg/kg) in combination with G/Nab-P achieved improved TGI (93% and 95%, respectively; p<0.0001 vs. vehicle) and induced tumor regression in 30% (3/10) and 60% (6/10) of mice, respectively. SM08502 (25 mg/kg QD) was also assessed in 4 patient-derived xenograft (PDX) models of TNBC (Crown Biosciences). Inhibition of tumor growth was observed in all tested PDX models (average TGI=69% [60-81], p<0.01 vs. vehicle). SM08502 was well tolerated in all tested xenograft models based on body weight measurements. In summary, SM08502 potently inhibited cell proliferation and expression of Wnt pathway-related genes in TNBC cell lines. SM08502 demonstrated strong in vivo antitumor effects in TNBC xenografts and PDX models and appeared to suppress lung metastasis. Additionally, SM08502 induced tumor regression in combination with G/Nab-P in TNBC xenografts, whereas G/Nab-P alone did not. These data suggest that SM08502 as a single agent or combined with standard chemotherapy has the potential to provide clinical benefit in TNBC. A Phase 1 study assessing safety, tolerability, and pharmacokinetics of SM08502 in subjects with advanced solid tumors is ongoing (NCT03355066).

Citation Format: Heekyung Chung, Lauren Sitts, Emily Creger, John Duc Nguyen, Brian Eastman, Chi-Ching Mak, Sunil KC, Betty Tam, Carine Bossard, Timothy Phalen, Steven Cha. SM08502, a novel, small-molecule CDC-like kinase (CLK) inhibitor, demonstrates strong inhibition of the Wnt signaling pathway and antitumor effects as monotherapy and in combination with chemotherapy in triple-negative breast cancer (TNBC) models [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P3-13-01.

The CLK inhibitor SM08502 induces anti-tumor activity and reduces Wnt pathway gene expression in gastrointestinal cancer models

The Wnt/β-catenin signaling pathway is aberrantly activated in colorectal (CRC) and many other cancers, and novel strategies for effectively targeting it may be needed due to its complexity. In this report, SM08502, a novel small molecule in clinical development for the treatment of solid tumors, was shown to reduce Wnt pathway signaling and gene expression through potent inhibition of CDC-like kinase (CLK) activity. SM08502 inhibited serine and arginine rich splicing factor (SRSF) phosphorylation and disrupted spliceosome activity, which was associated with inhibition of Wnt pathway-related gene and protein expression. Additionally, SM08502 induced the generation of splicing variants of Wnt pathway genes, suggesting that its mechanism for inhibition of gene expression includes effects on alternative splicing. Orally administered SM08502 significantly inhibited growth of gastrointestinal tumors and decreased SRSF phosphorylation and Wnt pathway gene expression in xenograft mouse models. These data implicate CLKs in the regulation of Wnt signaling and represent a novel strategy for inhibiting Wnt pathway gene expression in cancers. SM08502 is a first-in-class CLK inhibitor being investigated in a Phase 1 clinical trial for subjects with advanced solid tumors (NCT03355066).

Effects of SM08502, a novel, oral small-molecule inhibitor of Wnt pathway signaling, on gene expression and antitumor activity in colorectal cancer (CRC) models

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Background: Aberrant activation of Wnt signaling contributing to tumorigenesis is most commonly associated with CRC (90% harbor Wnt pathway mutations). SM08502, a novel, oral Wnt signaling pathway inhibitor, was evaluated in preclinical CRC models. Methods: In vitro Wnt signaling: assessed using TOPflash β-catenin/TCF reporter assay in SW480 human CRC cells. In vitro Wnt pathway gene expression: measured by qRT-PCR in SW480 and Wnt3a-stimulated cells (HEK-293T, IEC-6), and with the Nanostring Wnt pathway array (180 genes) across a panel of 16 CRC cell lines. In vitro cell proliferation: 17 CRC cell lines were used to test cell viability following treatment. In vivo antitumor activity: Oral SM08502 was tested in CRC mouse xenografts (SW480, HCT 116) and a PDX model over 20-21 days (QD, QOD). 24-hr pharmacodynamic (PD) analysis of Wnt pathway gene expression was done in SW480 tumor explants from mice following one 25 mg/kg dose. Results: SM08502 inhibited Wnt pathway signaling (EC50 = 46 nM) in SW480 cells. Wnt pathway gene expression was inhibited by SM08502 (0.3-3 µM) in Wnt3a-stimulated cells ( AXIN2, LEF1) and SW480 ( AXIN2, CTNNB1, LEF1, MYC, TCF7, TCF7L2) at 24 hrs ( P < .05 vs. vehicle) . Corresponding effects on protein expression were confirmed for all genes except CTNNB1, suggesting SM08502 acted independently of β-catenin. Nanostring array screening identified inhibition of LRP5, DVL2, BTRC, and ERBB2 by SM08502. Cell proliferation was inhibited in all 17 lines (avg. EC50 = 177 nM). In vivo, SM08502 was well tolerated and induced dose-dependent antitumor effects in xenografts and PDX models. Tumor growth inhibition for 25 mg/kg QD (max dose) was 83%, 56%, and 70% in SW480, HCT 116, and PDX, respectively. PD analysis showed significant inhibition ( P< .05 vs. vehicle) of TCF7, MYC, LRP5, DVL2, and BTRC expression 8 hrs post treatment. Conclusions: In preclinical CRC models, SM08502 was a potent inhibitor of Wnt pathway signaling and gene expression. It showed strong antitumor activity in human tumor models with activating Wnt pathway mutations. The safety, tolerability, and PK of SM08502 are being evaluated in an ongoing phase 1 study (NCT03355066).

Absolute percentage of biopsied tissue positive for Gleason pattern 4 disease (APP4) appears predictive of disease control after high dose rate brachytherapy and external beam radiotherapy in intermediate risk prostate cancer

BACKGROUND AND PURPOSE

To identify if, in intermediate risk prostate cancer (IR-PCa), the absolute percentage of biopsied tissue positive for pattern 4 disease (APP4) may be a predictor of outcome.

MATERIALS AND METHODS

411 patients with IR-PCa were retrospectively reviewed. APP4 was calculated based on biopsy reports. Multivariable competing risk analysis was then performed on optimized APP4 cutpoints to predict for biochemical failure (BF), androgen deprivation use for BF (ADT-BF) and development of metastases (MD).

RESULTS

Median follow-up for the cohort was 5.2 (Inter Quartile Range: 2.9-6.6) years. Median baseline PSA was 7.3 (5.3-9.8) ng/mL. 234 (56.9%) patients had T1 and 177 (43.1%) had T2 disease. Median APP4 was 2.00 (0.75-7.50)%. 38 (9.3%) patients experienced BF. The optimal cutpoint of APP4 for BF was >3.3% with an area under the curve (AUC) of 0.66. 17 (4.1%) received ADT-BF. The ADT-BF cutpoint was >6.6% with an AUC of 0.72. Eight (2.0%) developed MD. The MD cutpoint was >17.5% with an AUC of 0.86. Using APP4 >3.3 vs ≤ 3.3, log-transformed baseline PSA ln(PSA) (HR 2.5, 1.1-6.1; p = 0.037) and APP4 (HR 2.3, 1.1-4.7; p = 0.031) predicted for BF. Using APP4 >6.6 vs ≤ 6.6, ln(PSA) (HR 4.2, 1.4-12.4; p = 0.010) and APP4 (HR 3.7, 1.4-10.0; p = 0.009) were predictive of ADT-BF. APP4 >17.5 vs ≤ 17.5 alone was predictive of MD (HR 25.7, 4.9-135.3; p < 0.001).

CONCLUSION

APP4 cutpoints of >3.3%, >6.6% and >17.5% were strongly associated with increased risk of BF, ADT-BF and developing MD respectively. These findings may inform future practice when treating IR-PCa but require external validation.