Abstract
Recent sequencing studies of head and neck squamous cell carcinomas (HNSCCs) have identified the phosphatidylinositol 3-kinase (PI3K) pathway as the most frequently mutated, oncogenic ...pathway in this cancer type. Despite the frequency of activating mutations or amplification in PIK3CA (the gene encoding the catalytic subunit of PI3K), targeted inhibitors of PI3K have shown limited clinical efficacy as monotherapies. To identify factors that might predict sensitivity and resistance to PI3K inhibitors, we tested a panel of more than 20 patient-derived HNSCC cell lines and observed varying sensitivity to PI3K inhibitors. While all cell lines were much more sensitive than fibroblasts to these drugs, responses varied widely; for pan-PI3K inhibitor BKM120, IC50 values ranged from 0.4 to 7.4 uM across the OSCC cell line panel. Responses to BKM120 not correlate with genetic or phenotypic features, including: PIK3CA mutation status copy number, RNA expression, p110a protein levels, and AKT phosphorylation at baseline and after inhibitor treatment.
In order to characterize potential mechanisms of PI3K inhibitor resistance in HNSCC, we have also developed and optimized an unbiased, high-throughput screening approach. We have used this assay to test ~1400 inhibitors as monotherapies and in combination with PI3K inhibitors HS-173 and BKM120 in several HNSCC models. Our initial screening data suggested that the combination of PI3K inhibitor and EGFR/HER2 inhibitor afatinib is synergistic in a subset of cell lines. After testing this combination in additional models, we identified some cell lines that were responsive to the combination of HS-173 and afatinib, but not HS-173 and either EGFR inhibitor gefitinib or HER2 inhibitor CP-724714. In Detroit 562 cells, combination treatment with 0.25 uM HS-173 and 2.5 uM afatinib resulted in 35% more trypan positive cells than either drug alone. This also induced significantly more trypan positivity than combinations of 0.25 uM HS-173 with 5 uM gefitinib or 5 uM CP-724714. Likewise, the same HS-173 + afatinib treatment resulted in 35% or greater increases in Annexin V positivity compared to gefitinib and CP-724714 combinations. Western blot analysis demonstrated that these doses of gefitinib, CP-724714 and afatinib all inhibited target after 20 minute treatment in this cell line.
Future studies will also examine additional factors that may predict PI3K inhibitor responses and will seek to better understand promising combination treatments and advance them for effective use in HNSCC patients.
Citation Format: Nicole Lynn Michmerhuizen, Chloe Matovina, Elizabeth Leonard, Micah Harris, Caitlin Heenan, Gabrielle Herbst, Susan K. Foltin, Aditi Kulkarni, Thomas E. Carey, Carol R. Bradford, Hui Jiang, Chad Brenner. Small molecule profiling uncovers the landscape uncovers the landscape of combinational PI3K inhibitor responses in HNSCC abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3940.
Abstract
Recent head and neck squamous cell carcinoma (HNSCC) sequencing studies have identified the phosphatidylinositol 3-kinase (PI3K) pathway as the most frequently mutated, oncogenic pathway in ...this cancer type. Despite frequent activating mutation or amplification in PIK3CA (the gene encoding the catalytic subunit of PI3K), targeted PI3K inhibitors have shown limited clinical efficacy as monotherapies. To identify factors that might predict sensitivity and resistance to PI3K inhibitors, we tested a panel of more than 40 patient-derived HNSCC cell lines and observed varying sensitivity to PI3K inhibitors. While all cell lines were much more sensitive than fibroblasts to these drugs, responses varied widely; for pan-PI3K inhibitor BKM120, IC50 values ranged from 0.2 to 4.2 μM across the OSCC cell line panel. Responses to BKM120 do not correlate with PIK3CA mutation status copy number, RNA expression, p110α protein levels, and AKT phosphorylation at baseline and after inhibitor treatment, among other genetic or phenotypic features.
In order to characterize potential mechanisms of PI3K inhibitor resistance in HNSCC, we have also developed and optimized an unbiased, high-throughput screening approach. We have used this assay to test ~1400 inhibitors as monotherapies and in combination with PI3K inhibitors HS-173 and BKM120 in ten HNSCC models. Our initial screening data suggested that combinations of PI3K inhibitors and ALK inhibitors are among the most synergistic in a subset of cell lines. We have evaluated the effects of these drug combinations on apoptosis, cell cycle, and downstream signaling in several in vitro HNSCC models, observing synergy in response to FDA-approved agents PI3K inhibitor pictilisib and ALK inhibitor brigatinib in various systems using a range of techniques. We next plan to expand these analyses to organoid and xenograft models to evaluate their effects in more clinically relevant settings.
Future studies will also examine additional factors that may predict PI3K inhibitor responses and will seek to better understand promising combination treatments and advance them for effective use in HNSCC patients.
Citation Format: Nicole Lynn Michmerhuizen, Elizabeth Leonard, Caitlin Heenan, Vivek Nair, Chloe Matovina, Micah Harris, Gabrielle Herbst, Daniel Kim, Amanda Bachand, Jingyi Zhai, Susan K. Foltin, Aditi Kulkarni, Thomas E. Carey, Carol R. Bradford, Hui Jiang, John C. Brenner. Discovery of synergistic PI3K inhibitor combination therapies using high throughput approaches in HNSCC abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 322.
Chemical stabilization of microbial-derived products such as extracellular enzymes (EE) onto mineral surfaces has gained attention as a possibly important mechanism leading to the persistence of soil ...organic carbon (SOC). While the controls on EE activities and their stabilization in the surface soil are reasonably well-understood, how these activities change with soil depth and possibly diverge from those at the soil surface due to distinct physical, chemical, and biotic conditions remains unclear. We assessed EE activity to a depth of 1 m (10 cm increments) in 19 soil profiles across the Critical Zone Observatory Network, which represents a wide range of climates, soil orders, and vegetation types. For all EEs, activities per mass of soil correlated positively with microbial biomass (MB) and SOC, and all three of these variables decreased logarithmically with depth (p < 0.05). Across all sites, over half of the potential EE activities per mass soil consistently occurred below 20 cm for all measured EEs. Activities per unit MB or SOC were substantially higher at depth (soils below 20 cm accounted for 80% of whole-profile EE activity), suggesting an accumulation of stabilized (i.e., mineral sorbed) EEs in subsoil horizons. The pronounced enzyme stabilization in subsurface horizons was corroborated by mixed-effects models that showed a significant, positive relationship between clay concentration and MB-normalized EE activities in the subsoil. Furthermore, the negative relationships between soil C, N, and P and C-, N-, and P-acquiring EEs found in the surface soil decoupled below 20 cm, which could have also been caused by EE stabilization. This finding suggests that EEs may not reflect soil nutrient availabilities deeper in the soil profile. Taken together, our results suggest that deeper soil horizons hold a significant reservoir of EEs, and that the controls of subsoil EEs differ from their surface soil counterparts.
Tobacco smoke is an established carcinogen, but the association between tobacco smoking and cancer risk in BRCA mutation carriers is not clear. The aim of this study was to evaluate prospectively the ...association between tobacco smoking and cancer incidence in a cohort of BRCA1 and BRCA2 mutation carriers. The study population consisted of unaffected BRCA mutation carriers. Information on lifestyle including smoking histories, reproductive factors, and past medical histories was obtained through questionnaires. Incident cancers were updated biennially via follow‐up questionnaires. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using time‐dependent Cox regression models. There were 700 incident cancers diagnosed over 26,711 person‐years of follow‐up. The most frequent cancers seen in BRCA mutation carriers were breast (n = 428; 61%) and ovarian (n = 109; 15%) cancer. Compared to nonsmokers, (ever) smoking was associated with a modest increased risk of all cancers combined (HR = 1.17; 95%CI 1.01–1.37). Women in the highest group of total pack‐years (4.3–9.8) had an increased risk of developing any cancer (HR = 1.27; 95%CI 1.04–1.56), breast cancer (HR = 1.33, 95%CI 1.02–1.75), and ovarian cancer (HR = 1.68; 95%CI 1.06–2.67) compared to never smokers. The associations between tobacco smoking and cancer did not differ by BRCA mutation type or by age at diagnosis. This prospective study suggests that tobacco smoking is associated with a modest increase in the risks of breast and ovarian cancer among women with BRCA1 or BRCA2 mutation.
What's new?
Women who smoke are at increased risk of breast cancer. The degree to which smoking heightens risk in women with inherited BRCA1 or BRCA2 mutations, which are associated with high lifetime cancer risk, however, is unclear. This analysis of women with BRCA‐associated cancers implicates tobacco smoking as a significant risk factor, particularly for breast and ovarian cancers. Cancer risk was increased 31% for current smokers and 17% for ever smokers. BRCA mutation type and age at diagnosis had no impact on the associations. The findings are relevant to the care and counseling of BRCA mutation carriers.
Chemical stabilization of microbial-derived products such as extracellular enzymes (EE) onto mineral surfaces has gained attention as a possibly important mechanism leading to the persistence of soil ...organic carbon (SOC). While the controls on EE activities and their stabilization in the surface soil are reasonably well-understood, how these activities change with soil depth and possibly diverge from those at the soil surface due to distinct physical, chemical, and biotic conditions remains unclear. We assessed EE activity to a depth of 1 m (10 cm increments) in 19 soil profiles across the Critical Zone Observatory Network, which represents a wide range of climates, soil orders, and vegetation types. For all EEs, activities per mass of soil correlated positively with microbial biomass (MB) and SOC, and all three of these variables decreased logarithmically with depth (p < 0.05). Across all sites, over half of the potential EE activities per mass soil consistently occurred below 20 cm for all measured EEs. Activities per unit MB or SOC were substantially higher at depth (soils below 20 cm accounted for 80% of whole-profile EE activity), suggesting an accumulation of stabilized (i.e., mineral sorbed) EEs in subsoil horizons. The pronounced enzyme stabilization in subsurface horizons was corroborated by mixed-effects models that showed a significant, positive relationship between clay concentration and MB-normalized EE activities in the subsoil. Furthermore, the negative relationships between soil C, N, and P and C-, N-, and P-acquiring EEs found in the surface soil decoupled below 20 cm, which could have also been caused by EE stabilization. This finding suggests that EEs may not reflect soil nutrient availabilities deeper in the soil profile. Taken together, our results suggest that deeper soil horizons hold a significant reservoir of EEs, and that the controls of subsoil EEs differ from their surface soil counterparts.
Although evidence suggests that larger body size in early life confers lifelong protection from developing breast cancer, few studies have investigated the relationship between body size and breast ...cancer risk among BRCA mutation carriers. Therefore, we conducted a prospective evaluation of body size and the risk of breast cancer among BRCA mutation carriers.
Current height and body mass index (BMI) at age 18 were determined from baseline questionnaires. Current BMI and weight change since age 18 were calculated from updated biennial follow-up questionnaires. Cox proportional hazards models were used to estimate the hazard ratio (HR) and 95% confidence interval (CI).
Among 3734 BRCA mutation carriers, there were 338 incident breast cancers over a mean follow-up of 5.5 years. There was no association between height, current BMI or weight change and breast cancer risk. Women with BMI at age 18 ≥22.1 kg/m2 had a decreased risk of developing post-menopausal breast cancer compared with women with a BMI at age 18 between 18.8 and 20.3 kg/m2 (HR 0.49; 95% CI 0.30-0.82; P = 0.006). BMI at age 18 was not associated with risk of pre-menopausal breast cancer.
There was no observed association between height, current BMI and weight change and risk of breast cancer. The inverse relationship between greater BMI at age 18 and post-menopausal breast cancer further supports a role of early rather than current or adulthood exposures for BRCA-associated breast cancer development. Future studies with longer follow-up and additional measures of adiposity are necessary to confirm these findings.
IMPORTANCE: Cancer screening deficits during the first year of the COVID-19 pandemic were found to persist into 2021. Cancer-related deaths over the next decade are projected to increase if these ...deficits are not addressed. OBJECTIVE: To assess whether participation in a nationwide quality improvement (QI) collaborative, Return-to-Screening, was associated with restoration of cancer screening. DESIGN, SETTING, AND PARTICIPANTS: Accredited cancer programs electively enrolled in this QI study. Project-specific targets were established on the basis of differences in mean monthly screening test volumes (MTVs) between representative prepandemic (September 2019 and January 2020) and pandemic (September 2020 and January 2021) periods to restore prepandemic volumes and achieve a minimum of 10% increase in MTV. Local QI teams implemented evidence-based screening interventions from June to November 2021 (intervention period), iteratively adjusting interventions according to their MTVs and target. Interrupted time series analyses was used to identify the intervention effect. Data analysis was performed from January to April 2022. EXPOSURES: Collaborative QI support included provision of a Return-to-Screening plan-do-study-act protocol, evidence-based screening interventions, QI education, programmatic coordination, and calculation of screening deficits and targets. MAIN OUTCOMES AND MEASURES: The primary outcome was the proportion of QI projects reaching target MTV and counterfactual differences in the aggregate number of screening tests across time periods. RESULTS: Of 859 cancer screening QI projects (452 for breast cancer, 134 for colorectal cancer, 244 for lung cancer, and 29 for cervical cancer) conducted by 786 accredited cancer programs, 676 projects (79%) reached their target MTV. There were no hospital characteristics associated with increased likelihood of reaching target MTV except for disease site (lung vs breast, odds ratio, 2.8; 95% CI, 1.7 to 4.7). During the preintervention period (April to May 2021), there was a decrease in the mean MTV (slope, −13.1 tests per month; 95% CI, −23.1 to −3.2 tests per month). Interventions were associated with a significant immediate (slope, 101.0 tests per month; 95% CI, 49.1 to 153.0 tests per month) and sustained (slope, 36.3 tests per month; 95% CI, 5.3 to 67.3 tests per month) increase in MTVs relative to the preintervention trends. Additional screening tests were performed during the intervention period compared with the prepandemic period (170 748 tests), the pandemic period (210 450 tests), and the preintervention period (722 427 tests). CONCLUSIONS AND RELEVANCE: In this QI study, participation in a national Return-to-Screening collaborative with a multifaceted QI intervention was associated with improvements in cancer screening. Future collaborative QI endeavors leveraging accreditation infrastructure may help address other gaps in cancer care.
BACKGROUND Lifestyle interventions produce short-term improvements in glycemia and cardiovascular disease (CVD) risk factors in individuals with type 2 diabetes mellitus, but no long-term data are ...available. We examined the effects of lifestyle intervention on changes in weight, fitness, and CVD risk factors during a 4-year study. METHODS The Look AHEAD (Action for Health in Diabetes) trial is a multicenter randomized clinical trial comparing the effects of an intensive lifestyle intervention (ILI) and diabetes support and education (DSE; the control group) on the incidence of major CVD events in 5145 overweight or obese individuals (59.5% female; mean age, 58.7 years) with type 2 diabetes mellitus. More than 93% of participants provided outcomes data at each annual assessment. RESULTS Averaged across 4 years, ILI participants had a greater percentage of weight loss than DSE participants (−6.15% vs −0.88%; P < .001) and greater improvements in treadmill fitness (12.74% vs 1.96%; P < .001), hemoglobin A1c level (−0.36% vs −0.09%; P < .001), systolic (−5.33 vs −2.97 mm Hg; P < .001) and diastolic (−2.92 vs −2.48 mm Hg; P = .01) blood pressure, and levels of high-density lipoprotein cholesterol (3.67 vs 1.97 mg/dL; P < .001) and triglycerides (−25.56 vs −19.75 mg/dL; P < .001). Reductions in low-density lipoprotein cholesterol levels were greater in DSE than ILI participants (−11.27 vs −12.84 mg/dL; P = .009) owing to greater use of medications to lower lipid levels in the DSE group. At 4 years, ILI participants maintained greater improvements than DSE participants in weight, fitness, hemoglobin A1c levels, systolic blood pressure, and high-density lipoprotein cholesterol levels. CONCLUSIONS Intensive lifestyle intervention can produce sustained weight loss and improvements in fitness, glycemic control, and CVD risk factors in individuals with type 2 diabetes. Whether these differences in risk factors translate to reduction in CVD events will ultimately be addressed by the Look AHEAD trial. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00017953Arch Intern Med. 2010;170(17):1566-1575-->
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