Effect of an online educational module incorporating real-time feedback on accuracy of polyp sizing in trainees: a randomized controlled trial

BACKGROUND

Although polyp size dictates surveillance intervals, endoscopists often estimate polyp size inaccurately. We hypothesized that an intervention providing didactic instruction and real-time feedback could significantly improve polyp size classification.

METHODS

We conducted a multicenter randomized controlled trial to evaluate the impact of different components of an online educational module on polyp sizing. Participants were randomized to control (no video, no feedback), video only, feedback only, or video + feedback. The primary outcome was accuracy of polyp size classification into clinically relevant categories (diminutive [1-5mm], small [6-9mm], large [≥10mm]). Secondary outcomes included accuracy of exact polyp size (inmm), learning curves, and directionality of inaccuracy (over- vs. underestimation).

RESULTS

36 trainees from five training programs provided 1360 polyp size assessments. The feedback only (80.1%, P=0.01) and video + feedback (78.9%, P=0.02) groups had higher accuracy of polyp size classification compared with controls (71.6%). There was no significant difference in accuracy between the video only group (74.4%) and controls (P=0.42). Groups receiving feedback had higher accuracy of exact polyp size (inmm) and higher peak learning curves. Polyps were more likely to be overestimated than underestimated, and 29.3% of size inaccuracies impacted recommended surveillance intervals.

CONCLUSIONS

Our online educational module significantly improved polyp size classification. Real-time feedback appeared to be a critical component in improving accuracy. This scalable and no-cost educational module could significantly decrease under- and overutilization of colonoscopy, improving patient outcomes while increasing colonoscopy access.

Characterizing the Impact of Race and Redlining on Receipt of Guideline-Compliant Locoregional Therapy among Older Women with Breast Cancer

PURPOSE/OBJECTIVE(S)

Breast cancer (BC) is one of few malignancies in which improved locoregional control has been shown to improve overall survival. Contemporary redlining, or mortgage lending bias on the basis of home location, is a form of structural racism which has been demonstrated to impact BC survival in older patients. Self-reported race has been thought to serve as a surrogate for interpersonal racism and has similarly been shown to have associations with survival, redlining, and access to care. We aim to examine the relationship between race, redlining, and the receipt of guideline compliant locoregional therapy (LRT) in older women with BC.

MATERIALS/METHODS

Women aged 66-90 years with an initial Stage I-III BC diagnosis in 2010-2017 and known metropolitan statistical area (MSA) were identified in SEER-Medicare. Redlining was estimated using Home Mortgage Disclosure Act data (2010-2017). Guideline compliant LRT was assessed based on whether patients underwent surgery (lumpectomy or mastectomy), and if surgery was performed, whether they received adjuvant radiation treatment per the National Quality Forum and National Comprehensive Cancer Network guidelines in effect during the study period. A multiple logistic regression model was fitted to estimate ORs for the relationship between redlining and receipt of guideline compliant LRT, accounting for covariates (age, race/ethnicity, comorbidities, dual enrollment, tumor stage, hormone receptor status, census region, and year of diagnosis). Cluster bootstrap at the MSA-level was used to obtain P-values and confidence intervals.

RESULTS

The cohort included 64,987 women: 31% aged 66-70, 82% Non-Hispanic (NH) White, 7.4% NH Black, 24% with 2+ comorbidities, 12% with dual Medicaid/Medicare enrollment, 60% stage I, 31% stage II, and 77% HR+/HER2-. Overall, 6.4% did not undergo surgery; 84% received guideline compliant LRT. Women in the highest redlining areas had 81% guideline compliant LRT compared to 84-85% in the least, low and moderate redlined areas (p<0.001). However, model results revealed that contemporary redlining was not a predictor of guideline compliant LRT. NH Black women were less likely than NH White women to receive guideline-compliant LRT (OR 0.77, 95% CI 0.71-0.84, p<0.001). No significant differences were noted between NH White and NH Asian or Hispanic women.

CONCLUSION

In this population-based cohort of older women with breast cancer, NH Black race, even after adjusting for several important clinical and demographic factors, was associated with a lower likelihood of receiving guideline-compliant LRT. This finding demonstrates the profound impact of interpersonal racism on receipt of cancer-directed therapies. Though contemporary redlining did not significantly impact guideline-compliant LRT, further work is needed to identify systematic factors explaining known associations between contemporary redlining and BC survival.

Optimizing Endoscopy Procedure Documentation Improves Guideline-Adherent Care in Upper Gastrointestinal Bleeding

BACKGROUND AND AIMS

Upper GI bleeding (UGIB) is a common indication for inpatient esophagogastroduodenoscopy (EGD). Guideline adherence improves post-EGD care, including appropriate medication dosing/duration and follow-up procedures that reduce UGIB-related morbidity. We aimed to optimize and standardize post-EGD documentation to improve process and clinical outcomes in UGIB-related care.

METHODS

We performed a prospective quality improvement study of inpatient UGIB endoscopies at an academic tertiary referral center during 6/2019-7/2021. Guidelines were used to develop etiology/severity-specific electronic health record note templates. Participants (39 faculty/15 trainees) completed 10-min training in template content/use. We collected pre/post-intervention process data on "Minimal Standard Report" (MSR) documentation including patient disposition, diet, and medications. We also recorded documentation of re-bleed precautions and follow-up procedures. Study outcomes included guideline-based medication prescriptions, ordering of follow-up EGD, and post-discharge re-bleeding. Pre/post-intervention analysis was performed using chi-square tests.

RESULTS

From a pre-intervention baseline of 199 patients to 459 patients post-intervention, compliance improved with inpatient PPI (53.4-77.9%, p < 0.001) and discharge PPI (31.3-61.0%, p < 0.001) prescriptions. There was improvement in MSR completion (28.6-42.5%, p < 0.001). Compliance improved with octreotide prescriptions (75.0-93.6%, p = 0.002) and follow-up EGD order (61.3-87.1%, p < 0.001). There was no change in post-discharge re-bleeding. 82.6% of cases used templates.

CONCLUSIONS

Our project leveraged endoscopy software to standardize documentation, resulting in improved clinical care behavior and efficiency. Our intervention required low burden of maintenance, and sustainability with high utilization over 9 months. Similar endoscopy templates can be applied to other health systems and procedures to improve care.

Trends in the Incidence of Early-Onset Colorectal Adenocarcinoma Among Black and White US Residents Aged 40 to 49 Years, 2000-2017

IMPORTANCE

Early-onset colorectal cancer incidence rates are rising faster in White individuals than Black individuals. However, prior National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) racial stratification analyses used smaller SEER 13 databases, combined patients under age 50 years, did not stratify by sex, and did not focus on adenocarcinoma histologic subtypes (screening target).

OBJECTIVE

To perform a race- and sex-stratified adenocarcinoma incidence rate analysis in individuals aged 40 to 49 years using larger SEER 18 databases with expanded race data to better understand the colorectal cancer burden in those at or approaching screening age.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study used 2000 to 2017 SEER 18 annual age-adjusted colorectal cancer incidence rates stratified by anatomic subsite (colon or rectum), adenocarcinoma histology, race (non-Hispanic Black or non-Hispanic White), and sex for individuals aged 40 to 49 years, and yearly annual percent change (APC) incidence rates were calculated. Annual rate ratios (ARRs) between subgroups were determined. Statistical analysis was performed from January to March 2021.

MAIN OUTCOMES AND MEASUREMENTS

Early-onset colorectal cancer incidence rates, APCs, and ARRs.

RESULTS

In this study, a total of 46 728 colorectal cancer cases were identified in 45 429 patients aged 40 to 49 years from 2000 to 2017. Among the 45 429 patients included in this study, 6480 (14.2%) were Black and 27 426 (60.4%) were White; the mean (SD) age was 45.5 (2.8) years. Among White individuals aged 40 to 49 years, colorectal adenocarcinoma incidence rates increased from 19.6 per 100 000 person-years in 2000 to 25.2 per 100 000 person-years in 2017 (APC, 1.6; 95% CI, 1.3 to 1.9). Among Black individuals aged 40 to 49 years, colorectal adenocarcinoma incidence rates were not significantly changed (26.4 per 100 000 person-years in 2000 and 25.8 per 100 000 person-years in 2017 [APC, -0.03; 95% CI, -0.5 to 0.5]). There were no significant differences in ARRs of absolute colorectal incidence rates between White and Black individuals from 2014 to 2017. Rectal-only absolute adenocarcinoma incidence rates in Black and White individuals remained similar from 2000 to 2008 but significantly diverged in 2009. As of 2017, rectal absolute incidence rates were 39% higher among White individuals than among Black individuals with increasing APC (APC, 2.2; 95% CI, 1.6 to 2.8) whereas rectal adenocarcinoma incidence rates among Black individuals were decreasing, although the APC was not statistically significant (APC, -1.4; 95% CI, -2.6 to 0.1). Absolute colonic adenocarcinoma incidence rates remained higher in Black individuals. The study subgroups with the largest divergence in APCs were rectal adenocarcinoma in White vs Black women (APC of 2.2 [95% CI, 1.6 to 2.8] vs APC of -1.7 [95% CI, -3.6 to 0.3], respectively).

CONCLUSIONS AND RELEVANCE

This study found that colorectal adenocarcinoma incidence rates in people aged 40 to 49 years were increasing among White individuals but stabilized among Black individuals with absolute incidence rates becoming equivalent. Absolute rectal adenocarcinoma incidence rates were 39% lower in Black individuals with a widening disparity in rectal cancer between White and Black women. Possible contributors include introduction of a screening threshold of age 45 years in Black individuals in 2008. Although the average-risk screening age has now shifted to age 45 years in all racial groups, these data can help motivate real-world implementation of guidelines to maximize screening rates that have historically been suboptimal in younger individuals.

A pilot study investigating the in vitro efficacy of sucralfate against common veterinary cutaneous pathogens

OBJECTIVE

To determine whether Cicalfate® (Avene), a commercially available skin cream, or its active ingredient - sucralfate - demonstrate in vitro antimicrobial effect against common veterinary cutaneous pathogens.

MATERIALS AND METHODS

Prospective study assessing in vitro susceptibility of standardised and clinical strains of common veterinary cutaneous pathogens to titrated concentrations of sucralfate in either saline solution (range 0∙2 to 200 mg/mL) or in Cicalfate® restorative cream solubilised in DMSO (range 0∙002 to 1 mg/mL). Minimum inhibitory concentrations were determined by broth dilution in accordance with Clinical and Laboratory Standards Institute guidelines.

RESULTS

Both solutions demonstrated in vitro inhibitory effects against strains of Proteus mirabilis, Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus pseudintermedius, Escherichia coli and Enterococcus faecalis. Minimum inhibitory concentration ranges for susceptible bacteria tested in Cicalfate® solution and sucralfate solution were 0∙06 to 0∙25 mg/mL and 25 to 50 mg/mL, respectively. Sucralfate solution did not demonstrate antimicrobial effects against laboratory strains of S. aureus and E. faecalis and neither solution demonstrated antimicrobial effects against the clinical strain of P. aeruginosa. For organisms inhibited by sucralfate, Cicalfate® solution inhibited growth at lower sucralfate concentrations than sucralfate solution.

CLINICAL SIGNIFICANCE

The results of this pilot study suggest that Cicalfate® and sucralfate demonstrate in vitro antibacterial activity. Further in vitro and clinical studies are warranted to confirm these observations and determine their clinical utility in the treatment of superficial pyoderma.

Abstract 1940: Thymine DNA glycosylase (TDG) as a novel target for melanoma

Melanoma is an aggressive neoplasm with increasing incidence that bears the infamous distinction of being a recalcitrant cancer, i.e. a cancer with poor prognosis, lacking progress in diagnosis and treatment. In addition to conventional therapy, melanoma treatment is currently based on targeting the BRAF/MEK/ERK signal transduction pathway and immune checkpoints; however, advanced therapeutic approaches based on novel targets are urgently needed. We reasoned that the base excision repair enzyme Thymine DNA Glycosylase (TDG) could be such a target for its dual role in safeguarding genome stability and in effecting active DNA demethylation downstream the Ten-Eleven Translocation (TET) dioxygenases. TDG knockdown in melanoma cell lines causes cell cycle arrest, senescence and death by mitotic alterations, and impairs xenograft formation. Importantly, untransformed melanocytes are not affected by TDG knockdown, and adult mice with conditional knockout of TDG are viable. Candidate TDG inhibitors, identified through a high-throughput screen, reduced viability and clonogenic capacity of melanoma cell lines. Candidate TDG inhibitors increased cellular levels of 5-carboxylcytosine, the last intermediate in DNA demethylation, which is specifically removed by TDG, indicating successful targeting. These findings suggest that TDG may provide critical functions in cancer cells, but not in normal cells, that make it a highly suitable anti-melanoma drug target. By potentially disrupting both DNA repair and the epigenetic state, targeting TDG may represent a completely new approach to melanoma therapy.

Citation Format: Rossella Tricarico, Pietro Mancuso, Vikram Bhattacharjee, Laura Cosentino, Emmanuelle Nicolas, Margret Einarson, Neil Beeharry, Karthik Devarajan, Rich Katz, Dorjbal G. Dorjsuren, Anton Simeonov, Yuwaraj Kadariya, Guillaume Davidson, Joseph R. Testa, Irwin Davidson, Lionel Larue, Robert W. Sobol, Timothy Yen, Alfonso Bellacosa. Thymine DNA glycosylase (TDG) as a novel target for melanoma [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 1940.

Clinical implications of gastrointestinal symptoms in systemic amyloidosis

BACKGROUND

Gastrointestinal (GI) symptoms in systemic amyloidosis patients are poorly characterized. This purpose of this study is to define the epidemiology and clinical implications of such symptoms.

METHODS

This was a retrospective cohort study of 583 amyloid patients seen at a tertiary referral center. Of 96 symptomatic patients, 82 received endoscopic biopsies, subsequently grouped into those with histologic evidence of GI amyloid (biopsy proven) vs without (biopsy absent).

KEY RESULTS

16.8% of patients had GI symptoms, and had more abnormal NT-proBNP, cardiac ejection fraction, serum albumin, and alkaline phosphatase (P < .01). Of those who received endoscopy, the sites of highest diagnostic yield were stomach, duodenum and colon. The most common symptom was abdominal pain, nausea, or vomiting (50.0%). Of the symptomatic patients, only 37 (45%) had biopsy proven GI amyloid. Biopsy proven patients more often had cardiac involvement (P < .005), and more often received hematologic therapy or transplant (P = .01). Biopsy absent patients had more frequent neurologic involvement (P = .17). Biopsy status had no significant correlation with other indicators of amyloid burden, GI symptoms or management.

CONCLUSIONS & INFERENCES

Nearly one in six amyloid patients have GI symptoms, and half do not have GI amyloid. The type of symptom does not predict endoscopic findings. Most biopsy absent patients are not managed as a functional disorder despite no alternative etiology. Gastroenterologists may have an increased role to play in the care of systemic amyloidosis beyond performing endoscopies, such as evaluating cardiac amyloid patients for concurrent GI amyloid.

Abstract P5-16-09: Overall survival of patients with non-metastatic triple negative breast cancer who received neoadjuvant vs adjuvant chemotherapy: Cohort analysis of National cancer data base (NCDB) 2010 - 2011

Background: One of the benefits of neoadjuvant approach to the treatment of breast cancer is early microscopic disease control, which should translate to improved survival. However, clinical trials have not yet shown a survival benefit for neoadjuvant approach in even high risk patients, such as triple negative cases. Few studies have been performed outside of clinical trials.

Purpose: The objective of our study was to compare the overall survival of Stage I-III triple negative breast cancer patients who received neoadjuvant vs adjuvant chemotherapy within the NCDB, a prospectively collected, large, nationwide, hospital-based cancer outcomes database which contains information for more than 1,500 Commission on Cancer-accredited cancer programs in the U.S.

Patient and Method: We identified a cohort of women, aged &gt; 18 year-old at diagnosis, with clinical stage I-III triple negative breast cancer diagnosed in 2010-2011, who received either neoadjuvant chemotherapy only or adjuvant chemotherapy only. Patients with incomplete or missing vital status, receptors status and treatment information were excluded. Demographic (age at diagnosis, race, ethnicity, comorbidities, insurance, median income, urbanicity), tumor (clinical stage, histology, grade) and treatment (breast surgery, surgical margin, radiation) factors were examined. Stabilized inverse proportion weights were developed and assigned to balance the neoadjuvant and adjuvant groups on all demographic, tumor and treatment covariates. Unadjusted and adjusted overall survival was calculated using the Kaplan-Meier method and compared using the log-rank test.

Results: Among the 15,483 women with triple negative breast cancer, 4,335 (28%) received neoadjuvant chemotherapy and 11,148 (72%) received adjuvant chemotherapy. Most of the demographic, tumor and treatment factors were similarly distributed among neoadjuvant and adjuvant groups except age at diagnosis and clinical stage. Compared to patients received adjuvant chemotherapy, patients received neoadjuvant chemotherapy were more likely to be younger (45% vs. 31% &lt; 50 year-old, p&lt;0.0001) and have a higher clinical stage (35% vs. 6% stage III, p&lt;0.0001). The unadjusted 4-year overall survival of patients received neoadjuvant vs adjuvant approach was 75.8% (95% CI 74.4%-77.4%) and 87.5% (95% CI 87.1%-87.9%), respectively. After adjusting for demographic, tumor and treatment factors, the 4-year overall survival of patients received neoadjuvant vs adjuvant approach was 81.9% (95% CI 79.5%-84.3%) and 85.3% (95% CI 85.2%-85.4%), respectively.

Conclusion: In this NCDB study, the overall survival of triple negative breast cancer patients received neoadjuvant chemotherapy was inferior to those received adjuvant chemotherapy, even after adjusting for demographic, tumor and treatment factors. However, information regarding the chemotherapy regimen used and whether a full course of chemotherapy was delivered (2 factors that affect disease response and outcome) was not available. Patient and tumor factors at the time of disease presentation that are important in determining which triple negative patients will benefit from neoadjuvant approach remain to be defined.

Citation Format: Cheng YC, Smith E, Yen T. Overall survival of patients with non-metastatic triple negative breast cancer who received neoadjuvant vs adjuvant chemotherapy: Cohort analysis of National cancer data base (NCDB) 2010 - 2011 [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P5-16-09.

Proteomic profiling of patient-derived glioblastoma xenografts identifies a subset with activated EGFR: implications for drug development

The development of drugs to inhibit glioblastoma (GBM) growth requires reliable pre-clinical models. To date, proteomic level validation of widely used patient-derived glioblastoma xenografts (PDGX) has not been performed. In the present study, we characterized 20 PDGX models according to subtype classification based on The Cancer Genome Atlas criteria, TP53, PTEN, IDH 1/2, and TERT promoter genetic analysis, EGFR amplification status, and examined their proteomic profiles against those of their parent tumors. The 20 PDGXs belonged to three of four The Cancer Genome Atlas subtypes: eight classical, eight mesenchymal, and four proneural; none neural. Amplification of EGFR gene was observed in 9 of 20 xenografts, and of these, 3 harbored the EGFRvIII mutation. We then performed proteomic profiling of PDGX, analyzing expression/activity of several proteins including EGFR. Levels of EGFR phosphorylated at Y1068 vary considerably between PDGX samples, and this pattern was also seen in primary GBM. Partitioning of 20 PDGX into high (n = 5) and low (n = 15) groups identified a panel of proteins associated with high EGFR activity. Thus, PDGX with high EGFR activity represent an excellent pre-clinical model to develop therapies for a subset of GBM patients whose tumors are characterized by high EGFR activity. Further, the proteins found to be associated with high EGFR activity can be monitored to assess the effectiveness of targeting EGFR. The development of drugs to inhibit glioblastoma (GBM) growth requires reliable pre-clinical models. We validated proteomic profiles using patient-derived glioblastoma xenografts (PDGX), characterizing 20 PDGX models according to subtype classification based on The Cancer Genome Atlas (TCGA) criteria, TP53, PTEN, IDH 1/2, and TERT promoter genetic analysis, EGFR amplification status, and examined their proteomic profiles against those of their parent tumors. Proteins found to be associated with high EGFR activity represent potential biomarkers for GBM monitoring.

Delirium after cardiac surgery: have we overlooked obstructive sleep apnea?

Obstructive sleep apnea is common in patients with cardiovascular disease. It is well known that cardiac surgery is a risk factor for delirium. Researchers have shown that obstructive sleep apnea is an independent risk factor for the occurrence of delirium. In this manuscript we speculate on how obstructive sleep apnea may increase the risk of delirium in patients with cardiac surgery. If this is found to be confirmed, we would have another target through which we can decrease the risk of delirium in this population.

Abstract 628: A novel chemoresistance mechanism: HuR post-trancriptionally regulates WEE1, the mitotic inhibitor, upon DNA damage in pancreatic adenocarcinoma cells

Introduction: We explored HuR's (an RNA binding protein) significance in the DNA damage response (DDR) in pancreatic ductal adenocarcinoma (PDA) cells.

Experimental Procedures: We treated PDA cells with DNA damaging agent's mitomycin C (MMC), oxaliplatin, cisplatin, carboplatin, gemcitabine and a PARP inhibitor (ABT-888). HuR subcellular localization was assessed by immunoblotting. Additionally, we measured γH2AX foci, a marker of DNA damage, by immunofluorescence. Drug sensitivity assays were performed in isogenic PDA cells that differed in HuR expression (siRNA oligos against HuR, cDNAs encoding HuR for overexpression, and appropriate controls). A BrdU/PI pulse chase experiment monitored the cell cycle progression after treating cells with low (150nM) and high (1μM) doses of MMC. Ribonucleoprotein-immunoprecipitation (RIP) assays were used to isolate mRNAs bound to HuR to identify HuR targets in the DDR.

Results: Enhanced-HuR cytoplasmic protein expression was observed in PDA cells exposed to all DNA damaging agents. Under high doses of certain DNA damaging agents (e.g., MMC) HuR was cleaved in a caspase-dependent manner. To assess HuR's role in the DDR, isogenic PDA cells lines manipulated with HuR levels were treated with MMC (150nM) for 2 hrs. γH2AX foci assay revealed a 3-fold increase in foci number with MMC treatment in the HuR depleted cells, as compared to the control cells, suggesting that DNA repair was delayed in the absence of HuR. Cell cycle analyses demonstrated that HuR-depleted PDA cells progressed through the G2/M checkpoint and into mitosis upon MMC treatment. A combinatorial approach with RIP-sequencing and an siRNA library screen for genes resistant to DNA damaging agents was performed, and WEE1, a mitotic inhibitor kinase, was identified as a novel HuR target. A separate RIP-qPCR experiment validated WEE1 as an HuR binder with 56-fold more expression upon MMC stress, compared to an IgG control-IP. WEE1 protein expression and Cdk1 (a target of the WEE1 kinase and G2/M phase regulator) phosphorylation was reduced in HuR depleted cells, validating HuR as an upstream post-transcriptional regulator of WEE1 and an indirect inhibitor of the cdk1-cyclin complex in the face of DNA damage.

Conclusions: We demonstrate that HuR-deficiency allows PDA cells to enter the cell cycle more efficiently upon DNA damage. This event is dependent on HuR's regulation of WEE1 leading to activation of the CDK1-cyclin complex. These data support a model where HuR is integral to the G2/M checkpoint, forcing a cell cycle recovery response which is critical for PDA cells to avoid DNA damage. Therefore, HuR promotes survival of PDA cells through its acute activation of the DDR pathway. Disruption of HuR's molecular interaction with WEE1 represents a therapeutic opportunity to enhance clinically utilized chemotherapeutic DNA damaging agents for PDA.

Citation Format: Shruti Lal, Richard A. Burkhart, Zoe Norris, Neil Beeharry, Vikram Bhattacharjee, Isidore Rigoutsos, Timothy Yen, Charles J. Yeo, Jordan M. Winter, Jonathan R. Brody. A novel chemoresistance mechanism: HuR post-trancriptionally regulates WEE1, the mitotic inhibitor, upon DNA damage in pancreatic adenocarcinoma cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 628. doi:10.1158/1538-7445.AM2013-628

Abstract 5373: Sensitizing pancreatic cancer cells to gemcitabine by inhibition of Chk1 and neutralization of anti-apoptotic Bcl-2 family members

In response to various DNA damaging insults, cells initiate a complex cascade of signaling pathways that arrest the cell cycle in order to facilitate repair. A critical protein in this process is Checkpoint kinase 1 (Chk1). Many chemotherapeutic agents target DNA, and thereby activate Chk1, in order to elicit cell death. Chk1 activation may contribute to drug resistance by providing an opportunity for cancer cells to remain arrested until the drug has been metabolized. Thus, inducing DNA damage and then inhibiting Chk1 is expected to force cells to resume the cell cycle inappropriately. Numerous studies have shown that combinatorial drug-treatment strategies using conventional chemotherapy and Chk1 inhibitors lead to increased cytotoxicity as compared to drug treatment alone. However, the interplay between cell cycle arrest, checkpoint inhibition and induction of cell death remains poorly understood. Here we characterize the response of various pancreatic cancer cell lines to gemcitabine, the standard chemotherapeutic option, along with Chk1 inhibitors. Using live-cell video microscopy, we identified two distinct responses: in one subset of cell lines, addition of various Chk1 inhibitors to gemcitabine arrested cells caused cells to prematurely enter mitosis where they either completed mitosis or died in mitosis. In contrast, a separate set of cell lines treated with gemcitabine and Chk1 inhibitors did not prematurely enter mitosis but instead died in interphase. These findings suggest a link between induction of DNA damage, checkpoint override and induction of cell death.

To establish a link between checkpoint abrogation using Chk1 inhibitors and induction of cell death, we utilized small molecule inhibitors that neutralize the effect anti-apoptotic Bcl-2 family members. Reports have demonstrated a correlation between anti-apoptotic protein levels and resistance to chemotherapeutic drugs. We hypothesized that attenuating the function of these critical cell survival proteins may potentiate cell death. Pancreatic cell lines treated with gemcitabine caused a cell cycle arrest but did not die during over 72h of observation. We tested whether gemcitabine-treated cells would be sensitized to the BH3 mimetic ABT-737. Using viability and apoptosis assays, we observed that gemcitabine, UCN-01 or ABT-737 alone had negligible effect on cell viability. However, co-treatment of BXPC3 cells with gemcitabine and ABT-737 led to an increase in cell death. Cell death was further potentiated by combining gemcitabine, UCN-01 and ABT-737.

Our data demonstrates that Chk1 plays a key role in eliciting checkpoint activation following DNA damage but also suggests a role for maintaining cell survival in the presence of DNA damage. Inhibiting Chk1 blocks cell survival and cell death can be enhanced by nullifying the anti-apoptotic Bcl-2 proteins.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5373. doi:10.1158/1538-7445.AM2011-5373

Effect of the introduction of a lumbar-puncture sticker and teaching manikin on junior staff documentation and performance of paediatric lumbar punctures

BACKGROUND

Performing a lumbar puncture in an unwell child can cause anxiety in both the parent and the junior doctor. There is increasing evidence of post-lumbar-puncture complications in this age group.

AIMS

To improve the documentation, consent for and technical performance of paediatric lumbar punctures to 100% of the required standard within 3 months.

SETTING

The paediatric emergency department of a the Royal North Shore Hospital (University of Sydney, Sydney, Australia).

PARTICIPANTS

Paediatric emergency staff, including residents, registrars and consultants.

METHODS

Medical records of 40 consecutive children who had undergone a lumbar puncture in the 6 months before the introduction of the lumbar-puncture proforma were reviewed. After introduction of the proforma, the records of 25 consecutive patients were reviewed to assess changes in the outcome measures. Before introduction of the proforma, junior medical staff were instructed in the procedure using specialised lumbar puncture manikins (Baby Stap; Laerdel, USA).

RESULTS

Before introduction of the proforma, the median number of documented indicators was 4, out of a maximum of 12. There was almost no documentation of parental consent, patient complications and analgesia. Introduction of the proforma resulted in a highly marked increase to a median of 12 documented indicators per patient (p<0.01, 95% confidence interval 6 to 8).

CONCLUSIONS

The introduction of a lumbar-puncture proforma and formal teaching sessions using a paediatric manikin led to a marked improvement in the documentation of paediatric lumbar-punctures. Lumbar-punctures can be performed only by accredited medical officers who have achieved competency on the lumbar-puncture teaching manikin.

SUV in pelvic lymph node is a significant prognostic factor in previously untreated squamous carcinoma of the uterine cervix

5051

Background: The aim of this prospective study was to identify prognostic factors (including 18F-fluorodeoxyglucose positron emission tomography [FDG-PET] parameters) in previously untreated squamous carcinoma of the uterine cervix with MRI- or CT-defined pelvic or para-aortic lymph node (PLN or PALN) metastasis. Methods: This study included pooled patients selected from two prospective studies who had untreated squamous cell cervical cancer and PLN or PALN metastasis (diagnostic score 3 or 4) by CT-MRI and additional FDG-PET scans were performed for primary staging. Recurrence-free and overall survivals (RFS and OS) were evaluated using the Kaplan-Meier method. Prognostic variables were assessed by the log-rank test and Cox proportional hazards regression method. Optimal cut-offs of standardized uptake value (SUV) in primary tumor, PLN and PALN were determined by receiver operating characteristic and area under the curve analysis. Results: A total of 70 patients were eligible for analysis. The follow-up time ranged 16–59 months (mean ± SD: 38 ± 18). In univariate analyses, FIGO stage ≥ III, PET defined bilateral PLN-positive, PET defined PLN-positive, PET defined PALN-positive and SUV cut-off of 3.04 at PLN and 4.18 at PALN were significant for RFS. FIGO stage ≥ III, SUV cut-offs of 2.94–3.15 at PLN and SUV cut-offs of 2.61–4.91 at PALN were significant for OS. Multivariate analysis showed only SUVmax cut-off of 3.04 at PLN was a significant adverse factors for RFS (RR: 10.1 95% CI 2.2–46.0; P = 0.003) and OS (RR: 11.7 95% CI 1.5–92.6; P = 0.019), while SUVmax cut-off of 4.18 at PALN (P = 0.062) was marginally significant for OS. Conclusions: SUVmax cut-off of 3.04 at PLN was a significant adverse factor for RFS and OS in previously untreated squamous carcinoma of the uterine cervix with MRI- or CT-defined PLN or PALN metastasis.

No significant financial relationships to disclose.

[Effect of the pharmacological agent hesperadin on breast and prostate tumor cultured cells]

Aurora B, which is important for cell division control, is highly expressed in large number of cancer cell lines. Hesperadin, a prototype of a pharmacological agent, is a small molecule inhibitor of catalytic activity of Aurora B. In present work we investigate effect of Hesperadin on breast--MCF7 and prostate adenocarcinoma--PC3, cancer cell lines. After Hesperadin treatment we observe stop of cell proliferation due to appearance of multiple mitotic defects caused by Aurora B activity reduction and elimination of checkpoint proteins--such as hBUBR1 and CENP-E--from kinetochores of mitotic chromosomes.

Il-10 up-regulates macrophage expression of the S100 protein S100A8

The murine calcium binding protein S100A8 (A8) is a leukocyte chemoattractant, but high levels may be protective and scavenge hypochlorite. A8 is induced by LPS, IFN-gamma, and TNF in elicited macrophages. Th2 cytokines generally suppress proinflammatory gene expression, and IL-4 and IL-13 partially decreased A8 induction in macrophages and endothelial cells stimulated by LPS or IFN. In contrast, IL-10 synergized with LPS and IFN to increase mRNA levels > or =9-fold and secreted A8 levels approximately 4-fold. IL-10 decreased the optimal time of mRNA expression induced by LPS from 24 to 8 h. Blocking experiments indicated that endogenous IL-10 contributes to gene induction by LPS. Cooperation between IL-10 and LPS was not due to altered mRNA stability but was dependent on de novo protein synthesis. Transfection analysis with A8 luciferase constructs confirmed that synergy was due to increased transcription. The region of the promoter involved was localized to a 178-bp fragment flanking the transcription start site of the gene. This region was also responsible for the suppressive effects of IL-4 and IL-13. Forskolin, CTP-cAMP, and PGE(2) also enhanced LPS- and IFN-induced A8 mRNA, whereas indomethacin significantly reduced synergy between IL-10 and LPS. Mitogen-activated protein kinase/cyclooxygenase 2/cAMP pathways involving CCAAT-enhancing binding protein, located within the active promoter, may mediate A8 gene up-regulation in a manner mechanistically distinct to genes regulated by IL-10 via the STAT pathway. A8 exhibits pleiotropic effects, and the high levels secreted as a result of IL-10 synergy may regulate untoward inflammatory damage by virtue of its an antioxidant capacity.

Somatic INK4a-ARF locus mutations: a significant mechanism of gene inactivation in squamous cell carcinomas of the head and neck

The INK4a-ARF locus is located on human chromosome 9p21 and is known to encode two functionally distinct tumor-suppressor genes. The p16(INK4a) (p16) tumor-suppressor gene product is a negative regulator of cyclin-dependent kinases 4 and 6, which in turn positively regulate progression of mammalian cells through the cell cycle. The p14(ARF) tumor-suppressor gene product specifically interacts with human double minute 2, leading to the subsequent stabilization of p53 and G(1) arrest. Previous investigations analyzing the p16 gene in squamous cell carcinomas of the head and neck (SCCHNs) have suggested the predominate inactivating events to be homozygous gene deletions and hypermethylation of the p16 promoter. Somatic mutational inactivation of p16 has been reported to be low (0-10%, with a combined incidence of 25 of 279, or 9%) and to play only a minor role in the development of SCCHN. The present study examined whether this particular mechanism of INK4a/ARF inactivation, specifically somatic mutation, has been underestimated in SCCHN by determining the mutational status of the p16 and p14(ARF) genes in 100 primary SCCHNs with the use of polymerase chain reaction technology and a highly sensitive, nonradioactive modification of single-stranded conformational polymorphism (SSCP) analysis termed "cold" SSCP. Exons 1alpha, 1beta, and 2 of INK4a/ARF were amplified using intron-based primers or a combination of intron- and exon-based primers. A total of 27 SCCHNs (27%) exhibited sequence alterations in this locus, 22 (22%) of which were somatic sequence alterations and five (5%) of which were a single polymorphism in codon 148. Of the 22 somatic alterations, 20 (91%) directly or indirectly involved exon 2, and two (9%) were located within exon 1alpha. No mutations were found in exon 1beta. All 22 somatic mutations would be expected to yield altered p16 proteins, but only 15 of them should affect p14(ARF) proteins. Specific somatic alterations included microdeletions or insertions (nine of 22, 41%), a microrearrangement (one of 22, 5%), and single nucleotide substitutions (12 of 22, 56%). In addition, we analyzed the functional characteristics of seven unique mutant p16 proteins identified in this study by assessing their ability to inhibit cyclin-dependent kinase 4 activity. Six of the seven mutant proteins tested exhibited reduced function compared with wild-type p16, ranging from minor decreases of function (twofold to eightfold) in four samples to total loss of function (29- to 38-fold decrease) in two other samples. Overall, somatic mutation of the INK4a/ARF tumor suppressor locus, resulting in functionally deficient p16 and possibly p14(ARF) proteins, seems to be a prevalent event in the development of SCCHN. Mol. Carcinog. 30:26-36, 2001.

Induction of the TRAIL receptor KILLER/DR5 in p53-dependent apoptosis but not growth arrest

The TRAIL death receptor KILLER/DR5 is induced by DNA damaging agents in wild-type p53-expressing cells. Here we show that, unlike the p53-target CDK-inhibitor p21WAF1/CIP1, the TRAIL death receptor KILLER/DR5 is only induced in cells undergoing p53-dependent apoptosis and not cell cycle arrest. Thus GM glioblastoma cells carrying an inducible MMTV-driven p53 gene undergo cell cycle arrest and upregulate p21 but not KILLER/DR5 expression upon dexamethasone exposure. WI38 normal lung fibroblasts undergoing cell cycle arrest in response to ionizing irradiation also induce p21 but not KILLER/DR5 gene expression. KILLER/DR5 upregulation is also deficient in irradiated lymphoblastoid cells derived from patients with Ataxia Teleangiectasia suggesting a role for the ATM-p53 pathway in regulating KILLER/DR5 expression after DNA damage. Inhibition of transcription by Actinomycin D blocks both KILLER/DR5 and p21 induction in cells undergoing p53-dependent apoptosis. Our results suggest that the p53-dependent transcriptional induction of KILLER/DR5 death receptor is restricted to cells undergoing apoptosis and not cells undergoing exclusively p53-dependent G1 arrest.

Lack of correlation between ATM protein expression and tumour cell radiosensitivity

PURPOSE

Cells derived from individuals in which the ataxia telangiectasia (ATM) gene is mutated are hypersensitive to ionizing radiation. Whether differences in ATM protein levels exist among human malignant glioma cell lines and whether such differences are correlated with cellular radiosensitivity were determined.

MATERIALS AND METHODS

Polyclonal antibodies were raised to separate regions of the ATM protein. ATM protein expression in human malignant glioma cell lines, SV40 transformed normal human fibroblasts and SV40 transformed AT fibroblasts was analysed by Western blotting. Reverse transcriptase polymerase chain reaction (RT-PCR) was used to assess the presence of ATM transcript.

RESULTS

While ATM protein was detected in all cell extracts, significant differences in the level of expression were observed. There was no apparent correlation between cellular radiosensitivity and differences in ATM protein levels in these human glioma cells. Extremely low levels of ATM protein were observed in M059J cells, which provide the only example of DNA-dependent protein kinase (DNA-PKcs) deficiency in a cell line of human origin.

CONCLUSIONS

Variations in the levels of ATM protein are insufficient to explain the differences in cellular radiosensitivity observed in a panel of human malignant glioma cell lines.

Induction of the S100 chemotactic protein, CP-10, in murine microvascular endothelial cells by proinflammatory stimuli

Microvascular endothelial cells (EC) have multiple functions in inflammatory responses, including the production of chemoattractants that enhance leukocyte transmigration into tissues. Chemotactic protein, 10 kD (CP-10), is an S100 protein with potent chemotactic activity for myeloid cells in vitro and in vivo and is expressed in neutrophils and lipopolysaccharide (LPS)-activated macrophages. We show here that CP-10 is induced in murine endothelioma cell lines (bEnd-3, sEnd-1, and tEnd-1) after activation with LPS and interleukin-1 (IL-1) but not tumor necrosis factor alpha (TNFalpha) or interferon gamma (IFNgamma). Induction was not mediated by endogenous release of IL-1 or TNFalpha and was not directly upregulated by phorbol myristate acetate, calcium ionophore, or vitamin D3. EC were exquisitely sensitive to IL-1 activation (3.4 U/mL) and CP-10 mRNA induction with IL-1 occurred earlier (8 hours) than with LPS (12 hours). Furthermore, some microvessels and capillaries in delayed-type hypersensitivity lesions expressed cytoplasmic CP-10. Responses to LPS and not IL-1 in vitro were regulated by the degree of cell confluence and by TNFalpha costimulation. The related MRP-14 mRNA had a different induction pattern. Monomeric and homodimeric CP-10 upregulated by activation was predominantly cell-associated. EC-derived CP-10 may contribute to amplification of inflammatory processes by enhancing leukocyte shape changes and transmigration in the microcirculation.

Isolation of full-length ATM cDNA and correction of the ataxia-telangiectasia cellular phenotype

A gene mutated in the human genetic disorder ataxia-telangiectasia (A-T), ATM, was recently identified by positional cloning. ATM is a member of the phosphatidylinositol-3-kinase superfamily, some of which are protein kinases and appear to have important roles in cell cycle control and radiation signal transduction. We describe herein, to our knowledge, for the first time, the cloning of a full-length cDNA for ATM and correction of multiple aspects of the radio-sensitive phenotype of A-T cells by transfection with this cDNA. Overexpression of ATM cDNA in A-T cells enhanced the survival of these cells in response to radiation exposure, decreased radiation-induced chromosome aberrations, reduced radio-resistant DNA synthesis, and partially corrected defective cell cycle checkpoints and induction of stress-activated protein kinase. This correction of the defects in A-T cells provides further evidence of the multiplicity of effector functions of the ATM protein and suggests possible approaches to gene therapy.

Interaction between ATM protein and c-Abl in response to DNA damage

The gene mutated in the autosomal recessive disorder ataxia telangiectasia (AT), designated ATM (for 'AT mutated'), is a member of a family of phosphatidylinositol-3-kinase-like enzymes that are involved in cell-cycle control, meiotic recombination, telomere length monitoring and DNA-damage response. Previous results have demonstrated that AT cells are hypersensitive to ionizing radiation and are defective at the G1/S checkpoint after radiation damage. Because cells lacking the protein tyrosine kinase c-Abl are also defective in radiation-induced G1 arrest, we investigated the possibility that ATM might interact with c-Abl in response to radiation damage. Here we show that ATM binds c-Abl constitutively in control cells but not in AT cells. Our results demonstrate that the SH3 domain of c-Abl interacts with a DPAPNPPHFP motif (residues 1,373-1,382) of ATM. The results also reveal that radiation-induction of c-Abl tyrosine kinase activity is diminished in AT cells. These findings indicate that ATM is involved in the activation of c-Abl by DNA damage and this interaction may in part mediate radiation-induced G1 arrest.

Cisplatin-induced platelet activation requires mononuclear cells: role of GMP-140 and modulation of procoagulant activity

Cytotoxic drugs may potentiate the thrombotic complications in patients with malignancies and platelet function abnormalities have been reported after initiation of cisplatin therapy. This report describes a prolonged activation of platelets over 6-24 h co-culture with peripheral blood mononuclear cells (PBM) by pharmacological doses of cisplatin. Cisplatin had no direct effect on platelets and depended on PBM to produce aggregation which was apparently not mediated by products of the cyclooxygenase or lipoxygenase pathways, by platelet activation factor (PAF) or by thrombin. Although platelet aggregation normally involves the binding of fibrinogen to the beta 3 integrin, GP IIb-IIIa, on activated platelets, the cisplatin-dependent platelet aggregation observed in the co-culture experiments was not inhibited by an anti-GP IIb-IIIa monoclonal antibody which blocks fibrinogen-dependent aggregation nor by an adhesive peptide containing the RGDS integrin recognition sequence. Rather, aggregation appeared to involve a novel 140 kD granule membrane protein (GMP-140) mediated mechanism since aggregation was almost completely blocked by Fab fragments of an antibody to GMP-140 and was inhibited by fluid-phase GMP-140. At concentrations of cisplatin, adriamycin, and LPS that induced equivalent levels of tissue factor of blood monocytes, prothrombinase activity was significantly greater in cultures containing cisplatin. Prothrombinase activity was dependent on the presence of platelets and the rate of thrombin formation was enhanced by factor Xa generated by the tissue factor-factor VIIa complex. These studies suggest that the vascular and thrombotic complications associated with cisplatin therapy are mediated, at least in part, by platelet activation and aggregation and monocyte procoagulant activity.