Rapid Gastric emptying in spontaneously hypertensive rats

OBJECTIVE

To assess the rate of gastric emptying in spontaneously hypertensive rats (SHR) and to evaluate rapid gastric emptying as a possible predisposing factor for hypertension. Rapid gastric emptying of carbohydrates, known to elevate postprandial serum glucose, has been reported to occur in many insulin-resistant states, including hypertension. SHR exhibit insulin resistance similar to human hypertensive patients. No prior studies have assessed gastric emptying of an oral glucose solution in SHR as compared with control Wistar Kyoto rats (WKY).

METHODS

Using scintigraphic imaging, gastric emptying of a physiologic, orally consumed glucose solution was assessed in 12 SHR and 12 control WKY at 5 weeks of age, prior to the development of hypertension, and at 12 weeks of age after hypertension was fully established.

RESULTS

At 5 weeks, the gastric half-emptying time (GHET) was 67.8 ± 9.8 min for the SHR vs. 109.3 ± 18 ( P  = 0.042) minutes for the WKY controls. At 12 weeks, the GHET was 37.29 ± 10.3 min for the SHR vs. 138.53 ± 37.6 ( P  = 0.016) min for the WKY controls.

CONCLUSION

Gastric emptying was significantly more rapid in the SHR before and after the development of hypertension. Even though SHR are known to have increased sympathetic activity associated with their development of hypertension, this increased sympathetic activity does not inhibit gastric emptying. SHR are a promising animal model for investigating therapeutic agents for treating hypertension aimed at slowing the rate of gastric emptying.

Mechanical circulatory support versus vasopressors alone in patients with acute myocardial infarction and cardiogenic shock undergoing percutaneous coronary intervention

BACKGROUND

Previous studies have compared Impella use to intra-aortic balloon pump (IABP) use in patients with acute myocardial infarction and cardiogenic shock (AMI-CS) undergoing percutaneous coronary intervention (PCI). Our objective was to compare clinical outcomes in patients with AMI-CS undergoing PCI who received Impella (percutaneous left ventricular assist device) without vasopressors, IABP without vasopressors, and vasopressors without mechanical circulatory support (MCS).

METHODS

We queried the National Inpatient Sample (NIS) using ICD-10 codes (2015-2018) to identify patients with AMI-CS undergoing PCI. We created three propensity-matched cohorts to examine clinical outcomes in patients receiving Impella versus IABP, Impella versus vasopressors without MCS, and IABP versus vasopressors without MCS.

RESULTS

Among 17,762 patients, Impella use was associated with significantly higher in-hospital major bleeding (31.4% vs. 13.6%; p < 0.001) and hospital charges (p < 0.001) compared to IABP use, with no benefit in mortality (34.1% vs. 26.9%; p = 0.06). Impella use was associated with significantly higher mortality (42.3% vs. 35.7%; p = 0.02), major bleeding (33.9% vs. 22.7%; p = 0.001), and hospital charges (p < 0.001), when compared to the use of vasopressors without MCS. There were no significant differences in clinical outcomes between IABP use and the use of vasopressor without MCS.

CONCLUSIONS

In this analysis of retrospective data of patients with AMI-CS undergoing PCI, Impella use was associated with higher mortality, major bleeding, and in-hospital charges when compared to vasopressor therapy without MCS. When compared to IABP use, Impella was associated with no mortality benefit, along with higher major bleeding events and in-hospital charges. A vasopressor-only strategy suggested no difference in clinical outcomes when compared to IABP. This study uses the NIS for the first time to highlight outcomes in AMI-CS patients undergoing PCI when treated with vasopressor support without MCS, compared to Impella and IABP use.

Determination of safe levels of persistent organic pollutants in toxicology and epidemiology

We reviewed published manuscripts from toxicology and epidemiology reporting harmful health effects and doses of persistent organic pollutants (POPs), published between 2000 and 2021. We found 42 in vitro, 32 in vivo, and 74 epidemiological studies and abstracted the dose associated with harm in a common Molar unit. We hypothesized that the dose associated with harm would vary between animal and human studies. To test this hypothesis, for each of several POPs, we assessed the significance of variation in the dose associated with a harmful effect [categorized as non-thyroid endocrine (NTE), developmental neurotoxicity (DNT), and Thyroid] with study type (in vitro, in vivo, and Epidemiology) using a linear model after adjustment for basis (lipid weight, wet weight). We created a Calculated Safety Factor (CSF) defined as the toxicology dose divided by epidemiology dose needed to exhibit significant harm. Significant differences were found between study types ranging from <1 to 5.0 orders of magnitude in the dose associated with harm. Our CSFs in lipid weight varied from 12.4 (95% confidence interval (CI) 3.3, 47) for NTE effects in Epidemiology relative to in vivo studies to 6,244 (95% CI 2510, 15530) for DNT effects in Epidemiology relative to in vitro in wet weight representing 12.4 to 6.2 thousand-fold more sensitivity in people relative to animals, and mechanistic models, respectively. In lipid weight, all CSF 95% CI lower bounds across effect categories were less than 6.5. CIs for CSFs ranged from less than one to four orders of magnitude for in vivo, and two to five orders of magnitude for in vitro vs. Epidemiology. A global CSF for all Epidemiology vs. all Toxicology was 104.6 (95% CI 72 to 152), significant at p<0.001.

AXL-initiated paracrine activation of pSTAT3 enhances mesenchymal and vasculogenic supportive features of tumor-associated macrophages

Tumor-associated macrophages (TAMs) are integral to the development of complex tumor microenvironments (TMEs) and can execute disparate cellular programs in response to extracellular cues. However, upstream signaling processes underpinning this phenotypic plasticity remain to be elucidated. Here, we report that concordant AXL-STAT3 signaling in TAMs is triggered by lung cancer cells or cancer-associated fibroblasts in the cytokine milieu. This paracrine action drives TAM differentiation toward a tumor-promoting "M2-like" phenotype with upregulation of CD163 and putative mesenchymal markers, contributing to TAM heterogeneity and diverse cellular functions. One of the upregulated markers, CD44, mediated by AXL-IL-11-pSTAT3 signaling cascade, enhances macrophage ability to interact with endothelial cells and facilitate formation of primitive vascular networks. We also found that AXL-STAT3 inhibition can impede the recruitment of TAMs in a xenograft mouse model, thereby suppressing tumor growth. These findings suggest the potential application of AXL-STAT3-related markers to quantitatively assess metastatic potential and inform therapeutic strategies in lung cancer.

Non-chemotherapy adjuvant agents in TP53 mutant Ewing sarcoma

Ewing sarcoma (EWS) is a malignant tumor arising in bone or soft tissue that occurs in adolescent and young adult patients as well as adults later in life. Although non-metastatic EWS is typically responsive to treatment when newly diagnosed, relapsed cases have an unmet need for which no standard treatment approach exists. Recent phase III clinical trials for EWS comparing 7 vs 5 chemotherapy drugs have failed to improve survival. To extend the durability of remission for EWS, we investigated 3 non-chemotherapy adjuvant therapy drug candidates to be combined with chemotherapy. The efficacy of these adjuvant drugs was investigated via anchorage-dependent growth assays, anchorage-independent soft-agar colony formation assays and EWS xenograft mouse models. Enoxacin and entinostat were the most effective adjuvant drug in both long-term in vitro and in vivo adjuvant studies. In the context that enoxacin is an FDA-approved antibiotic, and that entinostat is an investigational agent not yet FDA-approved, we propose enoxacin as an adjuvant drug for further preclinical and clinical investigation in EWS patients.

Regulation of TORC1 by MAPK Signaling Determines Sensitivity and Acquired Resistance to Trametinib in Pediatric BRAFV600E Brain Tumor Models

PURPOSE

We investigated why three patient-derived xenograft (PDX) childhood BRAFV600E-mutant brain tumor models are highly sensitive to trametinib. Mechanisms of acquired resistance selected in situ, and approaches to prevent resistance were also examined, which may translate to both low-grade glioma (LGG) molecular subtypes.

EXPERIMENTAL DESIGN

Sensitivity to trametinib [MEK inhibitor (MEKi)] alone or in combination with rapamycin (TORC1 inhibitor), was evaluated in pediatric PDX models. The effect of combined treatment of trametinib with rapamycin on development of trametinib resistance in vivo was examined. PDX tissue and tumor cells from trametinib-resistant xenografts were characterized.

RESULTS

In pediatric models TORC1 is activated through ERK-mediated inactivation of the tuberous sclerosis complex (TSC): consequently inhibition of MEK also suppressed TORC1 signaling. Trametinib-induced tumor regression correlated with dual inhibition of MAPK/TORC1 signaling, and decoupling TORC1 regulation from BRAF/MAPK control conferred trametinib resistance. In mice, acquired resistance to trametinib developed within three cycles of therapy in all three PDX models. Resistance to trametinib developed in situ is tumor-cell-intrinsic and the mechanism was tumor line specific. Rapamycin retarded or blocked development of resistance.

CONCLUSIONS

In these three pediatric BRAF-mutant brain tumors, TORC1 signaling is controlled by the MAPK cascade. Trametinib suppressed both MAPK/TORC1 pathways leading to tumor regression. While low-dose intermittent rapamycin to enhance inhibition of TORC1 only modestly enhanced the antitumor activity of trametinib, it prevented or retarded development of trametinib resistance, suggesting future therapeutic approaches using rapamycin analogs in combination with MEKis that may be therapeutically beneficial in both KIAA1549::BRAF- and BRAFV600E-driven gliomas.

Abstract 1086: PEGylated talazoparib enhances therapeutic window of its combination with temozolomide in Ewing sarcoma

Introduction: The Ewing family of sarcomas is the fourth most common highly malignant childhood cancer. Current standard therapy is relatively ineffective for relapsed and metastatic Ewing sarcoma predominantly due to development of resistance to chemotherapeutics. Nanoparticle-formulated drugs are reported to increase uptake into tumor tissue, while reducing drug access to normal tissues, because of reduced permeability of normal vasculature. This potentially leads to lower dose exposure in normal tissues and reduced toxicity. The purpose of this study was to evaluate the antitumor activity of the PEGylated poly(ADP) ribose polymerase 1/2 (PARP1/2) inhibitor talazoparib combined with the DNA alkylating agent temozolomide (TMZ) in Ewing sarcoma xenograft models and other pediatric cancers.

Method:. We evaluated the preclinical efficacy of PEGylated talazoparib (PEG~TLZ), alone or in combination with TMZ, in Ewing sarcoma and glioblastoma patient derived xenograft (PDX) models. Additional solid tumor models, such as rhabdomyosarcoma, Wilms tumor, malignant rhabdoid tumor, osteosarcoma, and synovial sarcoma were evaluated using a novel single mouse testing approach. PEG~TLZ was administered as a single administration intraperitoneally to mice bearing subcutaneous tumors at a single dose of 5 - 20 µmol/kg alone, or at 10 µmol/kg on day 1 combined with TMZ administered orally at 40 mg/kg starting on day 3 or 4 for 5 consecutive days.

Results: Mice bearing Ewing sarcoma and MGMT-deficient glioblastoma xenografts tolerated PEG~TLZ+TMZ with minimal toxicity and achieved maintained complete response (MCR). The time-separated drug administration schedule of the single dose of PEG~TLZ followed by the 5-day TMZ treatment demonstrated objective responses in Ewing sarcoma, rhabdoid tumor, rhabdomyosarcoma, and glioblastoma PDX models.

Conclusion: We evaluated the range of PEG~TLZ+TMZ activity among pediatric solid tumor panels using conventional and single-mouse testing approaches, and demonstrated that PEG~TLZ combined with delayed TMZ administration enhances the therapeutic window of the treatment compared to free TLZ. From the clinical standpoint, the single intravenous administration of PEG~TLZ could be advantageous for treating infants and young children.

Citation Format: Vanessa Del Pozo, Andrew J. Robles, Shaun Fontaine, Qianqian Liu, Joel E. Michalek, Peter J. Houghton, Raushan Kurmasheva. PEGylated talazoparib enhances therapeutic window of its combination with temozolomide in Ewing sarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1086.

Abstract 4: Intercepting ribosomal protein S6KB1 signaling: Prevention of prostate cancer recurrence

There is an urgent need for innovative strategies such as the discovery of adjuvants that can prevent relapse and improve quality of life for patients treated with radiotherapy. Previously we demonstrated the utility of Nexrutine (Nex) as a neo-adjuvant with radiation. Nex was safe and well tolerated in PCa patients and potentiated radiation response in part through downregulation of ribosomal protein S6K (encoded byRPS6KB1). We now show that RPS6KB1 depleted prostate cancer cells with higher basal levels of γ-H2AX, a marker for DNA double strand breaks (i) are more sensitive to radiation and (ii) form smaller tumors with reduced levels of prostate specific antigen (PSA). Depletion of RPS6KB1 hindered DNA double-strand break repair predominantly through the alternate end-joining pathway, induction of G2/M checkpoint and NFκB pathway activation. Collectively these events led to improved radiation sensitivity. We further identified Berberine (Ber), one of the active constituents of Nex as a potential pharmacological inhibitor of RPS6KB1. In an orthotopic implantation model of C4-2B, treatment with Ber alone or Ber plus radiation decreased PSA levels that was sustained during the course of the experiment. On the other hand animals treated with radiation alone developed recurrent cancer as evidenced by a resurgence of PSA. Animals administered Ber followed by XRT intervention had increased levels of RANTES while there was no change in animals that received XRT followed by Ber. The observed reversal of the Bereffect with the sequence of intervention is statistically significant (p=0.0298). Among animals not subject to XRT, the mean PSA increased in those that did not receive Ber relative to those that did; mean difference=-1.93, 95% CI -3.75 to -0.105, p=0.04 with no significant changes in body weight. Notably,RPS6KB1 mRNA levels increased in tumor samples in patients experiencing biochemical recurrence(BCR). Given that rising PSA following conventional therapeutic approaches such as radiation remain a major clinical challenge, targeting RPS6KB1 signaling with radiation therapy is an attractive strategy to prevent BCR. Supported in part by CPRIT RP190012 (APK).

Citation Format: Addanki Pratap Kumar, Alison Clark, Michelle Villarreal, Sridharan Jayamohan, Shih-Bo Huang, Suleman S. Hussain, Xiaoyu Yang, Paul Rivas, Darpan Patel, Bethany L. Pierce, Shreya Tripathy, Pawel Osmulski, Maria Gaczynska, Lai Zhao, Li-Ju Wang, Yidong Chen, Caroline Xavier Paul Ezhilan, Mohan Natarajan, Joel E. Michalek, Robert L. Reddick, Rita Ghosh. Intercepting ribosomal protein S6KB1 signaling: Prevention of prostate cancer recurrence [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 4.

SMARCA4 biology in alveolar rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children and phenocopies a muscle precursor that fails to undergo terminal differentiation. The alveolar subtype (ARMS) has the poorest prognosis and represents the greatest unmet medical need for RMS. Emerging evidence supports the role of epigenetic dysregulation in RMS. Here we show that SMARCA4/BRG1, an ATP-dependent chromatin remodeling enzyme of the SWI/SNF complex, is prominently expressed in primary tumors from ARMS patients and cell cultures. Our validation studies for a CRISPR screen of 400 epigenetic targets identified SMARCA4 as a unique factor for long-term (but not short-term) tumor cell survival in ARMS. A SMARCA4/SMARCA2 protein degrader (ACBI-1) demonstrated similar long-term tumor cell dependence in vitro and in vivo. These results credential SMARCA4 as a tumor cell dependency factor and a therapeutic target in ARMS.

Bromodomain 4 inhibition leads to MYCN downregulation in Wilms tumor

BACKGROUND

Wilms tumor is the most common childhood kidney cancer. Two distinct histological subtypes of Wilms tumor have been described: tumors lacking anaplasia (the favorable subtype) and tumors displaying anaplastic features (the unfavorable subtype). Children with favorable disease generally have a very good prognosis, whereas those with anaplasia are oftentimes refractory to standard treatments and suffer poor outcomes, leading to an unmet clinical need. MYCN dysregulation has been associated with a number of pediatric cancers including Wilms tumor.

PROCEDURES

In this context, we undertook a functional genomics approach to uncover novel therapeutic strategies for those patients with anaplastic Wilms tumor. Genomic analysis and in vitro experimentation demonstrate that cell growth can be reduced by modulating MYCN overexpression via bromodomain 4 (BRD4) inhibition in both anaplastic and nonanaplastic Wilms tumor models.

RESULTS

We observed a time-dependent reduction of MYCN and MYCC protein levels upon BRD4 inhibition in Wilms tumor cell lines, which led to cell death and proliferation suppression. BRD4 inhibition significantly reduced tumor volumes in Wilms tumor patient-derived xenograft (PDX) mouse models.

CONCLUSIONS

We suggest that AZD5153, a novel dual-BRD4 inhibitor, can reduce MYCN levels in both anaplastic and nonanaplastic Wilms tumor cell lines, reduces tumor volume in Wilms tumor PDXs, and should be further explored for its therapeutic potential.

Coding Variation and Adherence to Methodological Standards in Cardiac Research Using the National Inpatient Sample

Background: Code selection is crucial to the accuracy and reproducibility of studies using administrative data, however a comprehensive assessment of coding trends for major cardiac diagnoses and procedures is lacking. We aimed to evaluate trends in administrative code utilization for major cardiac diagnoses and procedures, and adherence to required methodological practices in cardiac research using the National Inpatient Sample (NIS).

Methods: In this observational study of 445 articles, ICD-9-CM codes corresponding to acute myocardial infarction (AMI), heart failure, atrial fibrillation, percutaneous coronary intervention, and coronary artery bypass grafting were collected and analyzed. The NIS was used to compare the number of hospitalizations between the most frequently encountered AMI case definitions. Key elements were abstracted from each article to evaluate adherence to required methodological practices.

Results: Variation in code utilization was observed for each diagnosis and procedure assessed, and the number of unique case definitions published per year increased throughout the study period (P < 0.001), driven largely by the significant increase in articles per year (P < 0.001). Off-target codes were observed in 39 (8.8%) studies. Upon reintroduction into the NIS for 2008–2012, the most commonly encountered case definitions for AMI were found to yield significantly different estimates of AMI hospitalizations and hospitalization trends over time. Three hundred and ninety-nine articles (84%) did not adhere to one or more required research practices. Overall adherence was superior for publications in higher-impact journals (P = 0.002).

Conclusions: Substantial variation in code selection exists for major cardiac diagnoses and procedures, and non-adherence to methodological standards is widespread. These data have important implications for the accuracy and generalizability of analyses using the NIS.

Abstract PO-085: Therapeutic targeting of RPS6KB1/SQSTM1 axis to prevent biochemical recurrence

Radiation therapy (RT) is a standard treatment for organ confined prostate cancer (PCa). Given that both intrinsic and acquired resistance to radiation causes progression to advanced metastatic PCa, there is an unmet need for adjuvant therapies that synergize with radiation to improve therapeutic efficacy. Previously, we demonstrated strong synergistic tumor growth inhibitory activities for Phellodendron amurense bark extract in combination with radiation in part through downregulation of ribosomal protein S6K (encoded by RPS6KB1). Subsequently we identified berberine (Ber), one of the active constituents of Nexrutine as a potential pharmacological inhibitor of RPS6KB1. Given these findings, we hypothesized that targeting RPS6KB1 could be an approach to enhance sensitivity to radiation. We tested the efficacy of Ber alone and in combination with radiation using an orthotopic implantation model and the mechanism associated with radio-sensitization using prostate cancer cells stably silenced and deleted for RPS6KB1. We observed that (i) RPS6KB1 deletion in androgen responsive early stage LNCaP cells and (ii) stable silencing in castrate resistant C4-2B cells increased sensitization to radiation relative to respective parental or non-targeted cells. Furthermore, pharmacological inhibition of RPS6KB1 with Ber sensitized cells to radiation. Mechanistically, RPS6KB1 silencing increased autophagic activity as revealed by changes in proteins identified through reverse phase protein array (RPPA) and decreased expression and levels of SQSTM1 via downregulation of NFkB. Pretreatment with chloroquine (CQ) rescued the observed radio-sensitization effects. Treatment with Ber alone or Ber plus radiation decreased levels of PSA that was sustained during the course of the experiment in mice orthotopically implanted with C4-2B cells. On the other hand animals treated with radiation alone developed recurrent cancer as evidenced by a resurgence of PSA. Notably, RPS6KB1 mRNA levels increased in tumor samples in patients experiencing biochemical recurrence (BCR). Taken together, these findings demonstrate that RPS6KB1 is a clinically relevant target and that Ber sensitizes prostate cancer cells to radiation in vitro and in vivo. Therefore, targeting RPS6KB1 signaling is an attractive strategy to prevent progression to BCR; given that rising PSA following conventional therapeutic approaches such as radiation remain a major clinical challenge. This work is supported in part by CPRIT RP190012 (APK).

Citation Format: Addanki P. Kumar, Alison Clark, Michelle R. Villarreal, Shih-Bo Huang, Suleman S. Hussain, Xiaoyu Yang, Roble G. Bedolla, Paul Rivas, Sridharan Jayamohan, Li-Ju Wang, Yidong Chen, Caroline Xavier Paul Ezhilan, Mohan Natarajan, Joel E. Michalek, Robert Reddick, Hiroshi Miyamoto, Rita Ghosh. Therapeutic targeting of RPS6KB1/SQSTM1 axis to prevent biochemical recurrence [abstract]. In: Proceedings of the AACR Virtual Special Conference on Radiation Science and Medicine; 2021 Mar 2-3. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(8_Suppl):Abstract nr PO-085.

Interleukin-4 Receptor Inhibition Targeting Metastasis Independent of Macrophages

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma occurring in children and carries a dismal prognosis when metastatic disease is detected. Our previous work has suggested the cytokine receptor IL4Rα may play a role in contributing to metastasis in the alveolar subtype of rhabdomyosarcoma (aRMS), and thus could present a therapeutic target. The IL4 signaling axis has been characterized in various adult cancers as well; however, pediatric trials often follow similar adult trials and the role of the IL4Rα receptor has not been explored in the context of a mediator of metastasis in adult disease. Here, we demonstrate that the impact of IL4Rα blockade in an orthotopic allograft model of aRMS is not mediated by a macrophage response. We further examine the effect of IL4 blockade in adult colon, breast, and prostate cancers and find that inhibition of IL4Rα signaling modulates in vitro cell viability of HCT-116 colon carcinoma cells; however, this finding did not translate to an autocrine-related in vivo difference in tumor burden or lung metastasis. Our results suggest that if humanized IL4 mouse host strains are not available (or not ideal due to the need for immunosuppressing the host innate immune response for xenograft systems), then genetically-engineered mice and mouse allograft studies may be the best indicator of therapeutic targeting efficacy.

Receptor-driven invasion profiles in diffuse intrinsic pontine glioma

Background

Diffuse intrinsic pontine glioma (DIPG) is a devastating pediatric cancer with unmet clinical need. DIPG is invasive in nature, where tumor cells interweave into the fiber nerve tracts of the pons making the tumor unresectable. Accordingly, novel approaches in combating the disease are of utmost importance and receptor-driven cell invasion in the context of DIPG is under-researched area. Here, we investigated the impact on cell invasion mediated by PLEXINB1, PLEXINB2, platelet growth factor receptor (PDGFR)α, PDGFRβ, epithelial growth factor receptor (EGFR), activin receptor 1 (ACVR1), chemokine receptor 4 (CXCR4), and NOTCH1.

Methods

We used previously published RNA-sequencing data to measure gene expression of selected receptors in DIPG tumor tissue versus matched normal tissue controls (n = 18). We assessed protein expression of the corresponding genes using DIPG cell culture models. Then, we performed cell viability and cell invasion assays of DIPG cells stimulated with chemoattractants/ligands.

Results

RNA-sequencing data showed increased gene expression of receptor genes such as PLEXINB2, PDGFRα, EGFR, ACVR1, CXCR4, and NOTCH1 in DIPG tumors compared to the control tissues. Representative DIPG cell lines demonstrated correspondingly increased protein expression levels of these genes. Cell viability assays showed minimal effects of growth factors/chemokines on tumor cell growth in most instances. Recombinant SEMA4C, SEM4D, PDGF-AA, PDGF-BB, ACVA, CXCL12, and DLL4 ligand stimulation altered invasion in DIPG cells.

Conclusions

We show that no single growth factor-ligand pair universally induces DIPG cell invasion. However, our results reveal a potential to create a composite of cytokines or anti-cytokines to modulate DIPG cell invasion.

A Randomized Feasibility Trial Comparing Surveillance Regimens for Patients with Low and Low-Intermediate Risk Non-Muscle Invasive Bladder Cancer

BACKGROUND

Surveillance regimens for non-muscle invasive bladder cancer (NMIBC) are disparate and controlled trials could inform guidelines. The feasibility of randomizing patients to variable frequency surveillance is unknown.

OBJECTIVES

To determine patient willingness to randomization to high frequency (HF) versus low frequency (LF) surveillance regimen for NMIBC and compare patient comfort and healthcare costs across regimens.

METHODS

A non-blinded, two-arm, randomized-controlled study of patients with low or low-intermediate risk NMIBC was conducted at two institutions where patients were offered randomization to HF vs. LF surveillance following initial tumor resection. The HF group underwent cystoscopy every three months for 2 years, then every 6 months for 2 years, then annually. The LF group underwent cystoscopy at 9 months following the 3-month cystoscopy, then annually. Assuming 75% of patients approached would agree to enrollment, a sample size of n = 35 patients per arm provided a one-sided 95% exact Clopper-Pearson confidence lower-limit of 60%.

RESULTS

Of 70 patients approached, 45 (64.3%) agreed to participate and 25 (35.7%) declined enrollment due to preference for HF. Twelve biopsies were performed, including 4 (19%) of 21 patients in the HF group and 8 (33.3%) of 24 patients in the LF group. Disease recurrence (low grade Ta) was observed in 3 (14.3%) and 5 (20.8%) patients in the HF and LF groups, respectively. No patients experienced high grade recurrence or progression. Both groups had similar patient-reported procedure-related discomfort and quality of life measures over time. Patient out-of-pocket cost and healthcare systems costs were $383.80 more per patient annually in the HF group.

CONCLUSIONS

Randomization to variable frequency surveillance is challenging as over a third of patients declined participation. However, these data provide important preliminary insights into the potential effects of surveillance frequency on oncologic and economic outcomes in patients with low and low-intermediate risk bladder cancer.

Bladder Cancer Incidence and Survival in the United States and Texas Non-Latino Whites and Latinos

BACKGROUND: Bladder cancer (BC) poses an enormous burden on health care systems. Latinos in Texas (TX) were underrepresented in previous studies on racial/ethnic disparity of BC in the US. OBJECTIVE: To examine whether BC incidence and survival rates differ among Latinos compared to non-Latino whites (NLW) in South TX, TX, and the US SEER. METHODS: Data was collected from the US SEER Program and the Texas Cancer Registry. Annual age-specific and age-adjusted BC incidence rates and annual 5-year relative survival were calculated. RESULTS: South TX and TX had significantly lower BC incidence rates than SEER for both Latinos and NLW regardless of gender (Ps < 0.05). South TX women had worse BC survival rates than SEER women for both Latinos and NLW (Ps < 0.05). TX NLW had worse BC survival rates than SEER NLW for both genders together and men only (Ps < 0.05). All Latino groups had lower incidence but worse survival rates than NLW groups for both men and women in each geographic area (all Ps < 0.05). Women had significantly lower BC incidence but worse survival rates than men regardless of race/ethnicity in each geographic area (all Ps < 0.05). CONCLUSIONS: South TX women had lower BC incidence but worse survival rates than US SEER women for both Latinos and NLW. Latinos had worse survival but lower incidence rates than NLW. Women had lower BC incidence but worse survival rates than men. The study identifies the BC distribution and high-risk population, racial/ethnic disparities, and geographic differences. It facilitates health care services planning.

Carotenoid Intake and Circulating Carotenoids Are Inversely Associated with the Risk of Bladder Cancer: A Dose-Response Meta-analysis

Some evidence indicates that carotenoids may reduce the risk of bladder cancer (BC), but the association is unclear. We conducted a systematic review and meta-analysis of case-control and cohort studies investigating the relation between carotenoid intake or circulating carotenoid concentrations and BC risk in men and women. All relevant epidemiologic studies were identified by a search of PubMed and Scopus databases, and the Cochrane Library from inception to April 2019 with no restrictions. A random-effects model was used to calculate pooled RRs and their 95% CIs across studies for high compared with low categories of intake or circulating concentrations. We also performed a dose-response meta-analysis using the Greenland and Longnecker method and random-effects models. A total of 22 studies involving 516,740 adults were included in the meta-analysis. The pooled RRs of BC for the highest compared with the lowest category of carotenoid intake and circulating carotenoid concentrations were 0.88 (95% CI: 0.76, 1.03) and 0.36 (95% CI: 0.12, 1.07), respectively. The pooled RR of BC for the highest compared with lowest circulating lutein and zeaxanthin concentrations was 0.53 (95% CI: 0.33, 0.84). Dose-response analysis showed that BC risk decreased by 42% for every 1 mg increase in daily dietary β-cryptoxanthin intake (RR: 0.58; 95% CI: 0.36, 0.94); by 76% for every 1 μmol/L increase in circulating concentration of α-carotene (RR: 0.24; 95% CI: 0.08, 0.67); by 27% for every 1 μmol/L increase in circulating concentration of β-carotene (RR: 0.73; 95% CI: 0.57, 0.94); and by 56% for every 1 μmol/L increase in circulating concentrations of lutein and zeaxanthin (RR: 0.44; 95% CI: 0.28, 0.67). Dietary β-cryptoxanthin intake and circulating concentrations of α-carotene, β-carotene, and lutein and zeaxanthin were inversely associated with BC risk. The protocol was registered at PROSPERO as CRD42019133240.

Serum microRNA profiles among dioxin exposed veterans with monoclonal gammopathy of undetermined significance

Previously an increased risk for monoclonal gammopathy of undetermined significance (MGUS), a precursor of multiple myeloma (MM), was reported among Vietnam veterans exposed to Agent Orange and its contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Dysregulated expression of certain microRNAs (miRNAs) was demonstrated in MGUS and MM. Given the important role of miRNAs in cellular homeostasis, the aim of this study was to determine if there was an association between serum levels of selected miRNAs and TCDD in 47 MGUS cases identified in our previous investigation using serum specimens and exposure data archived by the Air Force Health Study (AFHS). A total of 13 miRNA levels (let-7a, let-7i, miR-16, miR-20a, miR-21, miR-34a, miR-106b, miR-146a, miR-181a, miR-192, miR-205, miR-335, and miR-361) was measured in serum stored during the 2002 AFHS follow-up and the relationship to lipid-adjusted serum TCDD levels in 1987 was determined. miR-34a showed the strongest relationship with TCDD; after age-adjustment, this positive association was more pronounced. In contrast, the other 12 miRNAs displayed absolute values of age adjusted coefficient estimates below 1.16 and non-significant p-values. The observed strong positive association between high body burdens of TCDD and miR-34a, a tumor suppressor regulated by p53, in this MGUS population warrants clarification of the TCDD-miR-34a relationship and its role in the pathogenesis of MGUS and risk for MM.

Intrapleural Impedance Sensor Real-Time Tracking of Pneumothorax in a Porcine Model of Air Leak

In patients with alveolar-to-pleural air leak due to recent surgery or trauma, clinicians tend to manage chest tubes with suction therapy. Nonsuction therapy is associated with shorter chest tube duration but also a higher risk of pneumothorax. We sought to develop an intrapleural electrical impedance sensor for continuous, real-time monitoring of pneumothorax development in a porcine model of air leak as a means of promoting nonsuction therapy. Using thoracoscopy, 2 chest tubes and the pleural impedance sensor were introduced into the pleural space of 3 pigs. Continuous air leak was introduced through 1 chest tube by carbon dioxide insufflation. The second chest tube was placed to suction then transitioned to no suction at increasingly higher air leaks until pneumothorax developed. Simultaneously, real-time impedance measurements were obtained from the pleural sensor. Fluoroscopy spot images were captured to verify the presence or absence of pneumothorax. Statistical Analysis Software was used throughout. With the chest tube on suction, a fully expanded lung was identified by a distinct pleural electrical impedance respiratory waveform. With transition of the chest tube to water seal, loss of contact of the sensor with the lung resulted in an immediate measurement of infinite electrical impedance. Pneumothorax resolution by restoring suction therapy was detected in real time by a return of the normal respiratory impedance waveform. Pleural electrical impedance monitoring detected pneumothorax development and resolution in real time. This simple technology has the potential to improve the safety and quality of chest tube management.

Continuous diffusion of oxygen improves diabetic foot ulcer healing when compared with a placebo control: a randomised, double-blind, multicentre study

OBJECTIVE

The aim of this study was to assess whether continuous diffusion of oxygen improves healing in people receiving treatment for diabetic foot ulcers (DFU).

METHOD

A double-blind, placebo control randomised study to receive either active continuous diffusion of oxygen (CDO) therapy using an active CDO device, or a fully operational placebo device without delivering oxygen. Patients were followed until closure or 12 weeks. Patients, caretakers, treating physicians and independent evaluators were blinded to the study arm. All patients received identical offloading, debridement, dressings and follow-up.

RESULTS

We enrolled 146 people with DFUs (77% male, aged 56.3±12.4 years). A significantly higher proportion (195%) of DFUs healed in the CDO arm compared with placebo (32.4% versus 16.7%, p=0.033). The time to 50% DFU closure was significantly shorter in patients that received CDO therapy (mean 18.4 versus 28.9 days, p=0.001). There were no differences in overall adverse events (p=0.66) or ulcer-related adverse events (p=0.30) in the active and placebo treatment groups. The relative performance of active CDO over placebo became greater when used in larger wounds (273%), in more chronic wounds (334%) and in weight bearing wounds (465%).

CONCLUSION

The results of this study demonstrate that CDO leads to higher proportion of healed DFUs (p=0.033) and a faster time to closure compared with placebo in people with DFUs (p=0.015). Relative performance did not vary significantly with wound size (p=0.80), but revealed better relative performance in more chronic wounds (p=0.008) and in weight-bearing wounds (p=0.003).

Ridge preservation following tooth extraction using bovine xenograft compared with porcine xenograft: A randomized controlled clinical trial

BACKGROUND

The primary purpose of this study was to histologically determine if there is a significant difference in new bone formation, residual graft material, and connective tissue/other when ridge preservation is accomplished using a bovine versus a porcine xenograft.

METHODS

Forty-four patients needing a single rooted tooth extraction and ridge preservation in preparation for dental implant placement were recruited in the study. After minimally traumatic tooth extraction, alveolar ridge dimensions were measured using a custom-fabricated acrylic stent. Patients were then randomized 1:1 to receive ridge preservation using either bovine or porcine xenograft material. A trimmed dense polytetrafluoroethylene (d-PTFE) membrane was overlaid on the graft material, the mucoperiosteal flaps were replaced, and the surgical site was sutured. After 18 to 20 weeks of wound healing, sites were surgically re-entered, ridge dimensions were again measured using the previously fabricated acrylic stents and a bone core sample of the grafted site was harvested for histomorphometric analysis.

RESULTS

Thirty eight of the 44 enrolled patients completed the study, 17 from the bovine group and 21 from the porcine group. Histologically, there were no statistically significant differences between the groups for mean percentage of vital bone formation (bovine = 36.21%, porcine = 31.27%, P = 0.49), residual graft material (bovine = 20.47%, porcine = 19.52%, P = 0.82) and connective tissue/other (bovine = 43.32%, porcine = 49.21%, P = 0.19). For secondary outcomes, there were no significant differences between the groups for mean change in buccal ridge height, lingual ridge height, and ridge width. However, a higher number of patients in the porcine group had additional grafting at the time of implant placement, either because of thin buccal plate or failure of implant stability.

CONCLUSION

The findings suggest that ridge preservation with porcine xenograft results in comparable histomorphometric outcomes and dimensional stability with bovine xenograft.

Preclinical rationale for entinostat in embryonal rhabdomyosarcoma

Background

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in the pediatric cancer population. Survival among metastatic RMS patients has remained dismal yet unimproved for years. We previously identified the class I-specific histone deacetylase inhibitor, entinostat (ENT), as a pharmacological agent that transcriptionally suppresses the PAX3:FOXO1 tumor-initiating fusion gene found in alveolar rhabdomyosarcoma (aRMS), and we further investigated the mechanism by which ENT suppresses PAX3:FOXO1 oncogene and demonstrated the preclinical efficacy of ENT in RMS orthotopic allograft and patient-derived xenograft (PDX) models. In this study, we investigated whether ENT also has antitumor activity in fusion-negative eRMS orthotopic allografts and PDX models either as a single agent or in combination with vincristine (VCR).

Methods

We tested the efficacy of ENT and VCR as single agents and in combination in orthotopic allograft and PDX mouse models of eRMS. We then performed CRISPR screening to identify which HDAC among the class I HDACs is responsible for tumor growth inhibition in eRMS. To analyze whether ENT treatment as a single agent or in combination with VCR induces myogenic differentiation, we performed hematoxylin and eosin (H&E) staining in tumors.

Results

ENT in combination with the chemotherapy VCR has synergistic antitumor activity in a subset of fusion-negative eRMS in orthotopic “allografts,” although PDX mouse models were too hypersensitive to the VCR dose used to detect synergy. Mechanistic studies involving CRISPR suggest that HDAC3 inhibition is the primary mechanism of cell-autonomous cytoreduction in eRMS. Following cytoreduction in vivo, residual tumor cells in the allograft models treated with chemotherapy undergo a dramatic, entinostat-induced (70–100%) conversion to non-proliferative rhabdomyoblasts.

Conclusion

Our results suggest that the targeting class I HDACs may provide a therapeutic benefit for selected patients with eRMS. ENT’s preclinical in vivo efficacy makes ENT a rational drug candidate in a phase II clinical trial for eRMS.

Electronic supplementary material

The online version of this article (10.1186/s13395-019-0198-x) contains supplementary material, which is available to authorized users.

Rapamycin Prevents Surgery-Induced Immune Dysfunction in Patients with Bladder Cancer

The mechanistic target of rapamycin (mTOR) integrates environmental inputs to regulate cellular growth and metabolism in tumors. However, mTOR also regulates T-cell differentiation and activation, rendering applications of mTOR inhibitors toward treating cancer complex. Preclinical data support distinct biphasic effects of rapamycin, with higher doses directly suppressing tumor cell growth and lower doses enhancing T-cell immunity. To address the translational relevance of these findings, the effects of the mTOR complex 1 (mTORC1) inhibitor, rapamycin, on tumor and T cells were monitored in patients undergoing cystectomy for bladder cancer. MB49 syngeneic murine bladder cancer models were tested to gain mechanistic insights. Surgery-induced T-cell exhaustion in humans and mice and was associated with increased pulmonary metastasis and decreased PD-L1 antibody efficacy in mouse bladder cancer. At 3 mg orally daily, rapamycin concentrations were 2-fold higher in bladder tissues than in blood. Rapamycin significantly inhibited tumor mTORC1, shown by decreased rpS6 phosphorylation in treated versus control patients (P = 0.008). Rapamycin reduced surgery-induced T-cell exhaustion in patients, evidenced by a significant decrease in the prevalence of dysfunctional programmed death-1 (PD-1)-expressing T cells. Grade 3 to 4 adverse event rates were similar between groups, but rapamycin-treated patients had a higher rate of wound complications versus controls. In conclusion, surgery promoted bladder cancer metastasis and decreased the efficacy of postoperative bladder cancer immunotherapy. Low-dose (3 mg daily) oral rapamycin has favorable pharmacodynamic and immune modulating activity in surgical patients and has the potential to decrease surgery-induced immune dysfunction.

The HDAC3-SMARCA4-miR-27a axis promotes expression of the PAX3:FOXO1 fusion oncogene in rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma of childhood with an unmet clinical need for decades. A single oncogenic fusion gene is associated with treatment resistance and a 40 to 45% decrease in overall survival. We previously showed that expression of this PAX3:FOXO1 fusion oncogene in alveolar RMS (aRMS) mediates tolerance to chemotherapy and radiotherapy and that the class I-specific histone deacetylase (HDAC) inhibitor entinostat reduces PAX3:FOXO1 protein abundance. Here, we established the antitumor efficacy of entinostat with chemotherapy in various preclinical cell and mouse models and found that HDAC3 inhibition was the primary mechanism of entinostat-induced suppression of PAX3:FOXO1 abundance. HDAC3 inhibition by entinostat decreased the activity of the chromatin remodeling enzyme SMARCA4, which, in turn, derepressed the microRNA miR-27a. This reexpression of miR-27a led to PAX3:FOXO1 mRNA destabilization and chemotherapy sensitization in aRMS cells in culture and in vivo. Furthermore, a phase 1 clinical trial (ADVL1513) has shown that entinostat is tolerable in children with relapsed or refractory solid tumors and is planned for phase 1B cohort expansion or phase 2 clinical trials. Together, these results implicate an HDAC3-SMARCA4-miR-27a-PAX3:FOXO1 circuit as a driver of chemoresistant aRMS and suggest that targeting this pathway with entinostat may be therapeutically effective in patients.

Pleural electrical impedance is a sensitive, real-time indicator of pneumothorax

BACKGROUND

Chest tube management protocols, particularly in patients with alveolar-pleural air leak due to recent surgery or trauma, are limited by concerns over safety, especially concerns about rapid and occult development of pneumothorax. A continuous, real-time monitor of pneumothorax could improve the quality and safety of chest tube management. We developed a rat model of pneumothorax to test a novel approach of measuring electrical impedance within the pleural space as a monitor of lung expansion.

MATERIALS AND METHODS

Anesthetized Sprague-Dawley rats underwent right thoracotomy. A novel impedance sensor and a thoracostomy tube were introduced into the right pleural space. Pneumothorax of varying volumes ranging from 0.2 to 20 mL was created by syringe injection of air via the thoracostomy tube. Electrical resistance measurements from the pleural sensor and fluoroscopic images were obtained at baseline and after the creation of pneumothorax and results compared.

RESULTS

A statistically significant, dose-dependent increase in electrical resistance was observed with increasing volume of pneumothorax. Resistance measurement allowed for continuous, real-time monitoring of pneumothorax development and the ability to track pneumothorax resolution by aspiration of air via the thoracostomy tube. Pleural resistance measurement demonstrated 100% sensitivity and specificity for all volumes of pneumothorax tested and was significantly more sensitive for pneumothorax detection than fluoroscopy.

CONCLUSIONS

The electrical impedance-based pleural space sensor described in this study provided sensitive and specific pneumothorax detection, which was superior to radiographic analysis. Real-time, continuous monitoring for pneumothorax has the potential to improve the safety, quality, and efficiency of postoperative chest tube management.

The impact of tackle football injuries on the American healthcare system with a neurological focus

BACKGROUND

Recent interest in the study of concussion and other neurological injuries has heightened awareness of the medical implications of American tackle football injuries amongst the public.

OBJECTIVE

Using the National Emergency Department Sample (NEDS) and the National Inpatient Sample (NIS), the largest publicly available all-payer emergency department and inpatient healthcare databases in the United States, we sought to describe the impact of tackle football injuries on the American healthcare system by delineating injuries, specifically neurological in nature, suffered as a consequence of tackle football between 2010 and 2013.

METHODS

The NEDS and NIS databases were queried to collect data on all patients presented to the emergency department (ED) and/or were admitted to hospitals with an ICD code for injuries related to American tackle football between the years 2010 and 2013. Subsequently those with football-related neurological injuries were abstracted using ICD codes for concussion, skull/face injury, intracranial injury, spine injury, and spinal cord injury (SCI). Patient demographics, length of hospital stay (LOS), cost and charge data, neurosurgical interventions, hospital type, and disposition were collected and analyzed.

RESULTS

A total of 819,000 patients presented to EDs for evaluation of injuries secondary to American tackle football between 2010 and 2013, with 1.13% having injuries requiring inpatient admission (average length of stay 2.4 days). 80.4% of the ED visits were from the pediatric population. Of note, a statistically significant increase in the number of pediatric concussions over time was demonstrated (OR = 1.1, 95% CI 1.1 to 1.2). Patients were more likely to be admitted to trauma centers, teaching hospitals, the south or west regions, or with private insurance. There were 471 spinal cord injuries and 1,908 total spine injuries. Ten patients died during the study time period. The combined ED and inpatient charges were $1.35 billion.

CONCLUSION

Injuries related to tackle football are a frequent cause of emergency room visits, specifically in the pediatric population, but severe acute trauma requiring inpatient admission or operative interventions are rare. Continued investigation in the long-term health impact of football related concussion and other repetitive lower impact trauma is warranted.

Rapamycin prevents surgery-induced T cell exhaustion in patients with bladder cancer

The mechanistic target of rapamycin (mTOR) integrates environmental inputs to regulate cellular growth and metabolism in tumors. However, mTOR also regulates T cell differentiation and activation, rendering applications of mTOR inhibitors towards treating cancer complex. Recent preclinical data supports distinct biphasic effects of rapamycin with higher doses directly suppressing tumor cell growth and lower doses enhancing T cell immunity. We conducted a randomized controlled pre-surgical clinical trial to study the tumor and immune effects of low dose mTOR complex 1 inhibition with rapamycin for patients with invasive, non-metastatic bladder cancer. At 3 mg daily for four weeks, rapamycin significantly inhibited tumor mTORC1 (ribosomal protein S6 phosphorylation), and achieved high bladder tissue levels. Rapamycin also reduced surgery-mediated T cell exhaustion, evidenced by a significant decrease in the prevalence of dysfunctional programmed death-1 (PD-1) expressing circulating T cells without decreasing T cell proliferation or cytokine production. In mice challenged with MB49 orthotopic bladder tumors, a 2 cm surgical laparotomy reduces the efficacy of α-PD-L1 immunotherapy but efficacy can be partly restored with presurgical administration of rapamycin. These findings support favorable delivery, pharmacodynamic activity, and immune modulatory profile of low dose rapamycin in bladder cancer and identifies a novel role for mTOR inhibition in modulating surgery-induced immune dysfunction.

Internal Mammary Lymph Node Biopsy During Free-Flap Breast Reconstruction: Optimizing Adjuvant Breast Cancer Treatment Through Comprehensive Staging

BACKGROUND

Accurate breast cancer staging is essential for optimal management of adjuvant therapies. While breast lymphatic drainage involves both axillary and internal mammary (IM) lymph node (LN) basins, IM LN sampling is not routinely advocated. The current study analyzes the incidence of IM LN metastases sampled during free flap breast reconstruction and subsequent changes in adjuvant treatment.

METHODS

A retrospective analysis of patients with positive IM LN biopsies during free flap breast reconstruction was performed. Pre-reconstruction surgical and adjuvant therapies as well as staging and prognostic data were recorded. Change in adjuvant therapies based solely on IM LN positivity was determined.

RESULTS

IM LN metastases were found on 28 (1.3%) out of 2057 patients and comprised the study population. Mean age was 49 years with pre-reconstruction chemotherapy or radiation administered in 50 or 54% of cases, respectively. Five (18%) patients had previously undergone lumpectomy with axillary sampling. Mean tumor size was 3.1 cm with tumor location evenly distributed among all four quadrants. Ten (36%) patients had isolated IM LN metastases Patients with both axillary and IM disease had larger lesions, increased prevalence of pre-reconstruction chemotherapy and radiation. Based exclusively on positive IM LN disease, 17 (63%) patients had a change in adjuvant therapy.

CONCLUSION

Despite the low incidence of IM LN metastases, IM LN biopsy during free flap breast reconstruction is recommended. In 36% of cases, nodal metastases were isolated to the IM nodes. Identification of IM metastases influenced adjuvant therapies in a majority of cases.

Diagnosis of Thin-Capped Fibroatheromas in Intravascular Optical Coherence Tomography Images: Effects of Light Scattering

BACKGROUND

Intravascular optical coherence tomography (IVOCT) images are recorded by detecting light backscattered within coronary arteries. We hypothesize that non-thin-capped fibroatheroma (TCFA) causes may scatter light to create the false appearance of IVOCT TCFA.

METHODS AND RESULTS

Ten human cadaver hearts were imaged with IVOCT (n=14 coronary arteries). IVOCT and histological TCFA images were coregistered and compared. Of 21 IVOCT TCFAs (fibrous cap <65 μm, lipid arc >1 quadrant), only 8 were true histological TCFA. Foam cell infiltration was responsible for 70% of false IVOCT TCFA and caused both thick-capped fibroatheromas to appear as TCFA, and the appearance of TCFAs when no lipid core was present. Other false IVOCT TCFA causes included smooth muscle cell-rich fibrous tissue (12%) and loose connective tissue (9%). If the lipid arc >1 quadrant (obtuse) criterion was disregarded, 45 IVOCT TCFAs were identified, and sensitivity of IVOCT TCFA detection increased from 63% to 87%, and specificity remained high at 92%.

CONCLUSIONS

We demonstrate that IVOCT can exhibit 87% (95% CI, 75%-93%) sensitivity and 92% specificity (95% CI, 86%-96%) to detect all lipid arcs (both obtuse and acute, <1 quadrant) TCFA, and we also propose new mechanisms involving light scattering that explain why other plaque components can masquerade as TCFA and cause low positive predictive value of IVOCT for TCFA detection (47% for obtuse lipid arcs). Disregarding the lipid arc >1 quadrant requirement enhances the ability of IVOCT to detect TCFA.

A Prospective, Randomized, Double-Blind Multicenter Study Comparing Continuous Diffusion of Oxygen Therapy to Sham Therapy in the Treatment of Diabetic Foot Ulcers

BACKGROUND

Over the past generation, preclinical data have suggested that there is a potential physiologic benefit to applying oxygen topically to wounds. However, we are unaware of any studies in the literature that have robustly assessed whether this would lead to a higher proportion of healing in similarly treated people without oxygen. Therefore, the purpose of this study was to assess this in people being treated for chronic diabetic foot ulcers (DFUs).

METHODS

We enrolled and randomized 100 subjects with DFUs (79% male, aged 58.3 ± 12.1 years) to receive either active continuous diffusion of oxygen (CDO) therapy using an active CDO device, or an otherwise fully operational sham device that provided moist wound therapy (MWT) without delivering oxygen. Patients were followed until closure or 12 weeks, whichever was sooner. Patients, treating physicians and independent evaluators were blinded to the study arm. All patients received identical offloading, dressings and follow-up.

RESULTS

There were no significant differences in assessed descriptive characteristics between the treatment arms ( P > .05 for all). A significantly higher proportion of people healed in the active arm compared to sham (46% vs 22%, P = .02). This relative effect became greater in more chronic wounds (42.5% vs 13.5%, P = .006). Patients randomized to the active device experienced significantly faster rates of closure relative to the sham ( P < .001).

CONCLUSIONS

The results of this study suggest that continuously diffused oxygen over a wound leads to significantly higher rates of closure, and faster time to closure, compared to similarly treated patients receiving standard therapy coupled with a sham device. Furthermore, the relative efficacy appears to improve the more the therapy may be needed (more chronic and larger wounds).

EphB4/EphrinB2 therapeutics in Rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma affecting children and is often diagnosed with concurrent metastases. Unfortunately, few effective therapies have been discovered that improve the long-term survival rate for children with metastatic disease. Here we determined effectiveness of targeting the receptor tyrosine kinase, EphB4, in both alveolar and embryonal RMS either directly through the inhibitory antibody, VasG3, or indirectly by blocking both forward and reverse signaling of EphB4 binding to EphrinB2, cognate ligand of EphB4. Clinically, EphB4 expression in eRMS was correlated with longer survival. Experimentally, inhibition of EphB4 with VasG3 in both aRMS and eRMS orthotopic xenograft and allograft models failed to alter tumor progression. Inhibition of EphB4 forward signaling using soluble EphB4 protein fused with murine serum albumin failed to affect eRMS model tumor progression, but did moderately slow progression in murine aRMS. We conclude that inhibition of EphB4 signaling with these agents is not a viable monotherapy for rhabdomyosarcoma.

p53-based strategy to reduce hematological toxicity of chemotherapy: A proof of principle study

p53 activation is a primary mechanism underlying pathological responses to DNA damaging agents such as chemotherapy and radiotherapy. Our recent animal studies showed that low dose arsenic (LDA)-induced transient p53 inhibition selectively protected normal tissues from chemotherapy-induced toxicity. Study objectives were to: 1) define the lowest safe dose of arsenic trioxide that transiently blocks p53 activation in patients and 2) assess the potential of LDA to decrease hematological toxicity from chemotherapy. Patients scheduled to receive minimum 4 cycles of myelosuppressive chemotherapy were eligible. For objective 1, dose escalation of LDA started at 0.005 mg/kg/day for 3 days. This dose satisfied objective 1 and was administered before chemotherapy cycles 2, 4, and 6 for objective 2. p53 level in peripheral lymphocytes was measured on day 1 of each cycle by ELISA assay. Chemotherapy cycles 1, 3, and 5 served as the baseline for the subsequent cycles of 2, 4, and 6 respectively. If p53 level for the subsequent cycle was lower (or higher) than the baseline cycle, p53 was defined as "suppressed" (or "activated") for the pair of cycles. Repeated measures linear models of CBC in terms of day, cycle, p53 activity and interaction terms were used. Twenty-six patients treated with 3 week cycle regimens form the base of analyses. The mean white blood cell, hemoglobin and absolute neutrophil counts were significantly higher in the "suppressed" relative to the "activated" group. These data support the proof of principle that suppression of p53 could lead to protection of bone marrow in patients receiving chemotherapy. This trial is registered in ClinicalTrials.gov. Identifier: NCT01428128.

Type 2 diabetes is associated with vertebral fractures in a sample of clinic- and hospital-based Latinos

Latinos are the fastest growing ethnic population in the United States and type 2 diabetes is a major health burden in this population, but little effort has been made to study the prevalence of diabetic vertebral fragility in Latinos. We performed a cross-sectional study to determine vertebral fracture prevalence in a hospital-based population of South Texas residents (N = 296). We defined fractures in X-rays as a >20% reduction in vertebral body height. Numerous variables were recorded, including age, body mass index, indicators of diabetes management and others. 71% of the sample (N = 296) was Latino. The prevalence of vertebral fracture was increased in diabetic subjects relative to non-diabetic subjects (diabetic 27.9%, non-diabetic 13.8%) and, regardless of sex and diabetics status, decreased in Latinos relative to non-Latinos (Latino 16.7%, non-Latino 26.4%). These data suggest that vertebral fractures may be a growing concern for diabetic Latinos as well as diabetics of any racial/ethnic background.

Early endothelial damage detected by circulating particles in baboons fed a diet high in simple carbohydrates in conjunction with saturated or unsaturated fat

Studies have shown that high-fat diets cause blood vessel damage, however, assessing pathological effects accurately and efficiently is difficult. In this study, we measured particle levels of static endothelium (CD31+ and CD105+) and activated endothelium (CD62E+, CD54+ and CD106+) in plasma. We determined individual responses to two dietary regimens in two groups of baboons. One group (n = 10), was fed a diet high in simple carbohydrates and saturated fats (the HSF diet) and the other (n = 8) received a diet high in simple carbohydrates and unsaturated fats (the HUF diet). Plasma samples were collected at 0, 3, and 7 weeks. The percentages of CD31+ and CD62E+ particles were elevated at 3 weeks in animals fed either diet, but these elevations were statistically significant only in animals fed the HUF diet. Surprisingly, both percentages and counts of CD31+ particles were significantly lower at week 7 compared to week 0 and 3 in the HSF group. The median absolute counts of CD105+ particles were progressively elevated over time in the HSF group with a significant increase from week 0 to 7; the pattern was somewhat different for the HUF group with significant increase from week 3 to 7. The counts of CD54+ particles exhibited wide variation in both groups during the dietary challenge, while the median counts of CD106+ particles were significantly lower at week 3 than at week 0 and week 7. Endothelial particles exhibited time-dependent changes, suggesting they were behaving as quantifiable surrogates for the early detection of vascular damage caused by dietary factors.

Diurnal salivary cortisol measurement in the neurosurgical-surgical intensive care unit in critically ill acute trauma patients

Acute trauma patients represent a specific subgroup of the critically ill population due to sudden and dramatic changes in homeostasis and consequently extreme demands on the activity of the hypothalamic-pituitary-adrenocortical (HPA) axis. Salivary cortisol is an accepted surrogate for serum free cortisol in the assessment of HPA axis function. The purpose of this study was (1) to establish the feasibility of salivary cortisol measurement in acute trauma patients in the neurosurgical-surgical intensive care unit (NSICU), and (2) to determine the diurnal pattern of salivary cortisol in the acute phase after injury. Saliva from 50 acute trauma patients was prospectively collected twice a day at 6AM and 4PM during the first week after injury in the NSICU. Mean PM cortisol concentrations were significantly higher in subjects versus controls (p<0.001). Subjects failed to develop the expected PM versus AM decrease in cortisol concentration seen in controls (p=0.005). Salivary cortisol did not vary significantly with baseline Glasgow Coma Scale (GCS), Injury Severity Score, sex, injury type, ethnicity, or age. When comparing mean AM and PM salivary cortisol by GCS severity category (GCS ⩽8 and GCS >8) the AM salivary cortisol was significantly higher in patients with GCS ⩽8 (p=0.002). The results show a loss of diurnal cortisol variation in acute trauma patient in the NSICU during the first week of hospitalization. Patients with severe brain injury had higher morning cortisol levels than those with mild/moderate brain injury.

Cell-cycle dependent expression of a translocation-mediated fusion oncogene mediates checkpoint adaptation in rhabdomyosarcoma

Rhabdomyosarcoma is the most commonly occurring soft-tissue sarcoma in childhood. Most rhabdomyosarcoma falls into one of two biologically distinct subgroups represented by alveolar or embryonal histology. The alveolar subtype harbors a translocation-mediated PAX3:FOXO1A fusion gene and has an extremely poor prognosis. However, tumor cells have heterogeneous expression for the fusion gene. Using a conditional genetic mouse model as well as human tumor cell lines, we show that that Pax3:Foxo1a expression is enriched in G₂ and triggers a transcriptional program conducive to checkpoint adaptation under stress conditions such as irradiation in vitro and in vivo. Pax3:Foxo1a also tolerizes tumor cells to clinically-established chemotherapy agents and emerging molecularly-targeted agents. Thus, the surprisingly dynamic regulation of the Pax3:Foxo1a locus is a paradigm that has important implications for the way in which oncogenes are modeled in cancer cells.

Rare childhood cancers can be paradigms from which important new principles can be discerned. The childhood muscle cancer rhabdomyosarcoma is no exception, having been the focus of the original 1969 description by Drs. Li and Fraumeni of a syndrome now know to be commonly caused by underlying p53 tumor suppressor loss-of-function. In our studies using a conditional genetic mouse model of alveolar rhabdomyosarcoma in conjunction with human tumor cell lines, we have uncovered that the expression level of a translocation-mediated fusion gene, Pax3:Foxo1a, is dynamic and varies during the cell cycle. Our studies support that Pax3:Foxo1a facilitate the yeast-related process of checkpoint adaptation under stresses such as irradiation. The broader implication of our studies is that distal cis elements (promoter-influencing regions of DNA) may be critical to fully understanding the function of cancer-associated translocations.

Rb1 loss modifies but does not initiate alveolar rhabdomyosarcoma

Background

Alveolar rhabdomyosarcoma (aRMS) is a myogenic childhood sarcoma frequently associated with a translocation-mediated fusion gene, Pax3:Foxo1a.

Methods

We investigated the complementary role of Rb1 loss in aRMS tumor initiation and progression using conditional mouse models.

Results

Rb1 loss was not a necessary and sufficient mutational event for rhabdomyosarcomagenesis, nor a strong cooperative initiating mutation. Instead, Rb1 loss was a modifier of progression and increased anaplasia and pleomorphism. Whereas Pax3:Foxo1a expression was unaltered, biomarkers of aRMS versus embryonal rhabdomyosarcoma were both increased, questioning whether these diagnostic markers are reliable in the context of Rb1 loss. Genome-wide gene expression in Pax3:Foxo1a,Rb1 tumors more closely approximated aRMS than embryonal rhabdomyosarcoma. Intrinsic loss of pRb function in aRMS was evidenced by insensitivity to a Cdk4/6 inhibitor regardless of whether Rb1 was intact or null. This loss of function could be attributed to low baseline Rb1, pRb and phospho-pRb expression in aRMS tumors for which the Rb1 locus was intact. Pax3:Foxo1a RNA interference did not increase pRb or improve Cdk inhibitor sensitivity. Human aRMS shared the feature of low and/or heterogeneous tumor cell pRb expression.

Conclusions

Rb1 loss from an already low pRb baseline is a significant disease modifier, raising the possibility that some cases of pleomorphic rhabdomyosarcoma may in fact be Pax3:Foxo1a-expressing aRMS with Rb1 or pRb loss of function.

Dynamic and nuclear expression of PDGFRα and IGF-1R in alveolar Rhabdomyosarcoma

Since the advent of tyrosine kinase inhibitors as targeted therapies in cancer, several receptor tyrosine kinases (RTK) have been identified as operationally important for disease progression. Rhabdomyosarcoma (RMS) is a malignancy in need of new treatment options; therefore, better understanding of the heterogeneity of RTKs would advance this goal. Here, alveolar RMS (aRMS) tumor cells derived from a transgenic mouse model expressing two such RTKs, platelet-derived growth factor (PDGFR)α and insulin-like growth factor (IGF)-1R, were investigated by fluorescence-activated cell sorting (FACS). Sorted subpopulations that were positive or negative for PDGFRα and IGF-1R dynamically altered their cell surface RTK expression profiles as early as the first cell division. Interestingly, a difference in total PDGFRα expression and nuclear IGF-1R expression was conserved in populations. Nuclear IGF-1R expression was greater than cytoplasmic IGF-1R in cells with initially high cell surface IGF-1R, and cells with high nuclear IGF-1R established tumors more efficiently in vivo. RNA interference-mediated silencing of IGF-1R in the subpopulation of cells initially harboring higher cell surface and total IGF-1R resulted in significantly reduced anchorage-independent colony formation as compared with cells with initially lower cell surface and total IGF-1R expression. Finally, in accordance with the findings observed in murine aRMS, human aRMS also had robust expression of nuclear IGF-1R.

IMPLICATIONS

RTK expression status and subcellular localization dynamics are important considerations for personalized medicine.

Abstract 1747: The Pax3:Foxo1a translocation product is a cell cycle-specific modifier of the alveolar rhabdomyosarcoma tumor phenotype

BACKGROUND: Rhabdomyosarcoma is the most common soft-tissue sarcoma in childhood, which falls into one of two biologically distinct subtypes, alveolar (aRMS) or embryonal rhabdomyosarcoma. aRMS harbors a translocation-mediated PAX3:FOXO1A fusion gene and has an extremely poor prognosis.

MATERIALS AND METHODS: Primary murine aRMS cultures were obtained from the Myf6Cre, Pax3:Foxo1a, p53 conditional mouse aRMS model, in which eYFP is expressed as a second cistron in the targeted Pax3:Foxo1a-ires-eYFP allele. Limited dilution transplantation experiments were performed using Pax3:Foxo1a knockdown by siRNA of eYFP or control aRMS primary cultures. To elucidate the dynamical function of Pax3:Foxo1a, time-lapse confocal microscopy experiments, cell cycle analysis, quantitative RT-PCR, western blotting, immunohistochemistry and mRNA array were performed using murine aRMS primary cell cultures with or without Pax3:Foxo1a knockdown treated by 6 Gy irradiation, or selected for ploidy using hoechst33342 sorted cell cycle-specific cells.

RESULTS: Pax3:Foxo1a is not required for tumor repopulating ability in mouse limiting-dilution transplantation experiments. The expression level of Pax3:Foxo1a was discovered to be dynamic and varied during the cell cycle in murine aRMS primary cell cultures and human aRMS cell lines. Pax3:Foxo1a is enriched in G2 and triggers a transcriptional program conducive to checkpoint adaptation in genome-wide expression analysis and quantitative RT-PCR. Radiation resulted in a higher fraction of DNA breaks amongst mitotic cells (as represented by dual pHH3 positive, H2AX positive cells) under conditions of Pax3:Foxo1a expression compared with knockdown, suggesting that Pax3:Foxo1a facilitates G2/M transit, consistent with checkpoint adaptation.

CONCLUSION: We demonstrated that Pax3:Foxo1a does not function in tumor cell maintenance, the expression level of Pax3:Foxo1a is dynamic and varies during the cell cycle, and Pax3:Foxo1a facilitates checkpoint adaptation under stress conditions such as irradiation. Furthermore, the surprisingly dynamic regulation of the Pax3:Foxo1a locus is a paradigm that has important implications for the way in which oncogenes are modeled in cancer biology.

Citation Format: Ken Kikuchi, Simone Hettmer, M. Imran Aslam, Joel E. Michalek, Wolfram Laub, Brian P. Rubin, Amy J. Wagers, Charles Keller. The Pax3:Foxo1a translocation product is a cell cycle-specific modifier of the alveolar rhabdomyosarcoma tumor phenotype. [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 1747. doi:10.1158/1538-7445.AM2013-1747

18F-FDG microPET imaging detects early transient response to an IGF1R inhibitor in genetically engineered rhabdomyosarcoma models

BACKGROUND

Alveolar rhabdomyosarcoma (ARMS) and embryonal rhabdomyosarcoma (ERMS) are among the most common and most treatment resistant soft tissue sarcomas of childhood. Here, we evaluated the potential of (18)F-Fluorodeoxyglucose (FDG) as a marker of therapeutic response to picropodophyllin (PPP), an IGF1R inhibitor, in a conditional mouse model of ARMS and a conditional model of ERMS/undifferentiated pleomorphic sarcoma (UPS).

PROCEDURE

Primary tumor cell cultures from Myf6Cre,Pax3:Fkhr,p53 and Pax7CreER,Ptch1,p53 conditional models of ARMS and ERMS/UPS were found to be highly sensitive to PPP (IC(50) values 150 and 200 nM, respectively). Animals of each model were then treated with 80 mg/kg/day PPP by intraperitoneal injection for 12 days and imaged by (18)F-FDG microPET.

RESULTS

Tumor volumes on day 4 for PPP-treated ARMS and ERMS mice were lower than untreated control mouse tumor volumes, although treated tumors were larger than day 0. However, tumor FDG uptake was significantly reduced on day 4 for PPP-treated mice compared to pretreatment baseline or untreated control mice on day 4 (P < 0.05). Nevertheless, by day 12 tumor volumes and FDG uptake for treated mice had increased significantly, indicating rapidly evolving resistance to therapy.

CONCLUSIONS

(18)F-FDG PET imaging is a potential imaging biomarker of molecular susceptibility to targeted agents early in treatment for this aggressive form of sarcoma, but may find best use serially for Phase I/II studies where chemotherapy and targeted agents are combined to cytoreduce tumors and abrogate Igf1r inhibitor resistance.

An adaptive Src-PDGFRA-Raf axis in rhabdomyosarcoma

Alveolar rhabdomyosarcoma (aRMS) is a very aggressive sarcoma of children and young adults. Our previous studies have shown that small molecule inhibition of Pdgfra is initially very effective in an aRMS mouse model. However, slowly evolving, acquired resistance to a narrow-spectrum kinase inhibitor (imatinib) was common. We identified Src family kinases (SFKs) to be potentiators of Pdgfra in murine aRMS primary cell cultures from mouse tumors with evolved resistance in vivo in comparison to untreated cultures. Treating the resistant primary cell cultures with a combination of Pdgfra and Src inhibitors had a strong additive effect on cell viability. In Pdgfra knockout tumors, however, the Src inhibitor had no effect on tumor cell viability. Sorafenib, whose targets include not only PDGFRA but also the Src downstream target Raf, was effective at inhibiting mouse and human tumor cell growth and halted progression of mouse aRMS tumors in vivo. These results suggest that an adaptive Src-Pdgfra-Raf-Mapk axis is relevant to PDGFRA inhibition in rhabdomyosarcoma.