Citations

To assess the role of telomerase activity and telomere length in pancreatic CSCs we used different CSC enrichment methods (CD133, ALDH, sphere formation) in primary patient-derived pancreatic cancer cells. We show that CSCs have higher telomerase activity and longer telomeres than bulk tumor cells. Inhibition of telomerase activity, using genetic knockdown or pharmacological inhibitor (BIBR1532), resulted in CSC marker depletion, abrogation of sphere formation in vitro and reduced tumorigenicity in vivo. Furthermore, we identify a positive feedback loop between stemness factors (NANOG, OCT3/4, SOX2, KLF4) and telomerase, which is essential for the self-renewal of CSCs. Disruption of the balance between telomerase activity and stemness factors eliminates CSCs via induction of DNA damage and apoptosis in primary patient-derived pancreatic cancer samples, opening future perspectives to avoid CSC-driven tumor relapse. In the present study, we demonstrate that telomerase regulation is critical for the “stemness” maintenance in pancreatic CSCs and examine the effects of telomerase inhibition as a potential treatment option of pancreatic cancer. This may significantly promote our understanding of PDAC tumor biology and may result in improved treatment for pancreatic cancer patients.

Abstract Background The proportion of women in the field of hematology and oncology (H&O) has increased over recent decades, but the representation of women in leadership positions remains poor. In an effort to close the gender gap in academia, it is important to report on such inequities in hopes to close these gaps and improve career development. Materials and Methods We conducted a retrospective, observational study of published award recipients from 1994 to 2019 from the seven major H&O societies in the world. Gender was determined based on publicly available data. The χ2 and Cochran-Armitage tests were used for data analysis. Results Of the 1,642 awardees over the past 26 years, 915 met inclusion criteria. Award recipients were overwhelmingly men (77.9%) and non-Hispanic White (84.7%). Women awardees received 30.3% of the humanistic and education-related awards, whereas only receiving 16.0% of basic science awards (p < .01). Women represent 35.6% of all hematologists and oncologists but only received 24.0% of awards given to these physicians (p = .004). Black, Hispanic, and Asian awardees represented 3.7%, 3.3%, and 6.8% of the total awardees, respectively. Conclusion From 1994 to 2019, women were less likely to receive recognition awards from the seven major H&O societies studied compared with men. We also observed a considerably low proportion of minority awardees across all oncology subspecialties. Further studies examining how selection criteria favor either gender would be warranted in order to achieve equal representation in academic awards. Implications for Practice In this study, women and minority groups were found to be underrepresented amongst award recipients. Significant disparities were seen in disciplines that have been historically male predominant, such as basic sciences. As awards on an international level enhance academic resumes and assist with career advancement, it is important that awards are being given in an equitable manner. First steps to promote diversity and inclusion in academic medicine is reporting of gender and racial disparities in various areas of academia.

Background: Thousands of gene fusions have been reported in prostate cancer, but their authenticity, incidence, and tumor specificity have not been thoroughly evaluated, nor have their genomic characteristics been carefully explored. Methods: We developed FusionVet to dedicatedly validate known fusion genes using RNA-seq alignments. Using FusionVet, we re-assessed 2727 gene fusions reported from 36 studies using the RNA-seq data generated by The Cancer Genome Atlas (TCGA). We also explored their genomic characteristics and interrogated the transcriptomic and DNA methylomic consequences of the E26 transformation-specific (ETS) fusions. Results: We found that nearly two-thirds of reported fusions are intra-chromosomal, and 80% of them were formed between 2 protein-coding genes. Although most (76%) genes were fused to only 1 partner, we observed many fusion hub genes that have multiple fusion partners, including ETS family genes, androgen receptor signaling pathway genes, tumor suppressor genes, and proto-oncogenes. More than 90% of the reported fusions cannot be validated by TCGA RNA-seq data. For those fusions that can be validated, 5% were detected from tumor and normal samples with similar frequencies, and only 4% (120 fusions) were tumor-specific. The occurrences of ERG, ETV1, and ETV4 fusions were mutually exclusive, and their fusion statuses were tightly associated with overexpressions. Besides, we found ERG fusions were significantly co-occurred with PTEN deletion but mutually exclusive with common genomic alterations such as SPOP mutation and FOXA1 mutation. Conclusions: Most of the reported fusion genes cannot be validated by TCGA samples. The ETS family and androgen response genes were significantly enriched in prostate cancer–specific fusion genes. Transcription activity was significantly repressed, and the DNA methylation was significantly increased in samples carrying ERG fusion.

Our understanding of altered neuro‐cardiovascular control following long‐duration inactivity via head‐down bed rest (HDBR) is incomplete. Here, we retrospectively analyzed two long‐duration HDBR studies, including female (n=17; 32±5 years) and male (n=16; 29±7 years) cohorts, to determine whether HDBR 1) alters spontaneous cardiovagal baroreflex sensitivity (cBRS) similarly between males and females and 2) alters spontaneous baroreflex control of muscle sympathetic action potentials (AP) in males. Heart rate (HR; electrocardiogram) and arterial blood pressure (BP; finger‐plethysmography) were continuously measured during 5‐minutes of supine rest prior to and following 60‐days bed rest in a ‐6° head‐down position. Spontaneous cBRS was assessed by the relationship between R‐R interval and systolic BP analyzed using the linear regression sequence method. Recordings of multi‐unit muscle sympathetic nerve activity (peroneal microneurography) were obtained and a continuous wavelet transform detected APs which were grouped into AP clusters with similar morphology (n=10, all males). Baroreflex threshold for AP cluster discharge was assessed by linear regression analysis of the relationship between AP cluster discharge probability and diastolic BP. No change in resting HR (64±9 versus 66±9 /min, P=0.12) or mean BP (91.2±9.0 versus 90.6±9.2 mmHg, P=0.73) occurred after HDBR. Reductions in cBRS after HDBR (‐4.1±9.4 ms/mmHg, Time effect: P<0.01) were similar between males and females (Time‐by‐Sex effect: P=0.51) and not related to changes in total blood volume (r 2 =0.045, P=0.24). Grouped AP clusters demonstrated heterogenous arterial baroreflex threshold gain according to AP cluster morphology (Cluster effect: P<0.01) which was unaltered following HDBR (Time‐by‐Cluster effect: P=0.43). In summary, males and females similarly attenuate cBRS following 60‐days of HDBR and novel evidence indicates HDBR does not alter spontaneous baroreflex control of muscle sympathetic APs in males.

In the renal proximal tubule (PT), Na + /K + ‐ATPase (NKA) is exclusively located in the basolateral domain. Through its classic ATP‐dependent ion‐pumping function, NKA generates the Na + gradient that drives apical Na + reabsorption, mostly through Na + /H + exchanger (NHE3). Accordingly, activation of NKA‐mediated ion transport decreases natriuresis through activation of basolateral (NKA) and apical Na + reabsorption (NHE3). In contrast, pharmacological evidence suggests that activation of the more recently discovered NKA signaling function triggers a cellular redistribution of NKA and NHE3 that decreases transcellular Na + flux in cultured PT cells. To obtain genetic evidence of this NKA/Src mechanism in the PT and asses its physiological importance, we used a knockdown and rescue approach in pig renal epithelial cells (LLC‐PK1). Additionally, we genetically targeted NKA α1 in the mouse PT by crossing mice expressing a sodium glucose co‐transporter 2 promoter driven Cre transgene with Floxed NKA α1 mice (PTα1 ‐/‐ ). Knockdown of 90% of NKA α1 in PT LLC‐PK1 cells increased transepithelial 22 Na flux by 2‐fold, activated NHE3 (50% decrease in inhibitory phosphorylation), and increased basolateral Na + /HCO 3 ‐ cotransporter (NBCe1A) protein content. In the PTα1 ‐/‐ mouse (4‐month males and females in a 1:1 ratio), 70% decrease in PT NKA α1 expression decreased urine output (0.51±0.14 vs 1.57±0.21 mL/24h in PTα1 +/+ , p<0.001, n=16) and absolute Na + excretion (0.14±0.05 vs 0.36±0.05 mmol/24h in PTα1 +/+ , p<0.05, n=8) by 65%, without histological or functional evidence of renal injury. Those changes were driven by increased PT Na + reabsorption, as indicated by a 65% decrease in lithium clearance (4‐month males, 1344±220 vs 3932±697 mL/24h in PTα1 +/+ , p<0.001, n=12) with unchanged GFR. This hyper‐reabsorptive phenotype of PTα1 ‐/‐ mice was coupled to increased membrane abundance of NHE3 and NBCe1A, and rescued upon crossing with floxed NHE3 mice, consistent a NKA/NHE3‐dependent mechanism. A dismantlement of caveolar NKA/Src receptor complex and intracellular redistribution of pY418Src occurred in knockdown NKA α1 PT cells, and was also observed in the PTα1 ‐/‐ hypomorphic mouse. Rescue of PT cells with wild‐type but not Src signaling‐null NKA α1 restored NHE3 and NBCe1A to basal levels, indicative of a role for NKA/Src receptor function in the tonic inhibition of Na + transporters in the PT. Hence, NKA signaling exerts a tonic inhibition on Na + reabsorption by regulating key apical and basolateral Na + transporters. This action, which is lifted upon NKA genetic suppression in cells and in vivo , tonically counteracts NKA's ATP‐driven function of basolateral Na + reabsorption. Strikingly, NKA/Src signaling is not only physiologically relevant, it is functionally dominant over NKA ion‐pumping in the control of PT reabsorption. NKA signaling therefore provides a long sought‐after mechanism for the natriuretic action of endogenous NKA ligands such as cardiotonic steroids.

e16109 Background: Total gastrectomy with lymph node dissection is curative for early gastric malignancy which accounts for 1.5% of cancer cases in the U.S. Readmissions are common postoperatively, and are associated with increased morbidity, mortality, hospital costs and decreased quality of life. We hence aim to identify incidence, impact and independent predictors for readmission in patients who underwent total gastrectomy in gastric malignancy. Methods: We conducted a retrospective cohort study of the 2017 National Readmission Database (NRD) of adult patients readmitted within 30 days after an index admission for total gastrectomy with a concomitant diagnosis of gastric malignancy. T-test was used for continuous variables and chi square test was used for categorical variables. Multivariate regression was used to identify predictors for unplanned readmissions. ICD 10 codes were used to identify diagnoses and procedures. Results: A total of 1,779 patients with gastric malignancy underwent total gastrectomy. The 30-day readmission rate was 18.5%. Main causes for readmission were sepsis, ventricular fibrillation, recurrent STEMI. Readmitted patients were more likely to be on chemotherapy. (40.1% vs 27.2%; P<0.01) and more likely to be discharged to a skilled facility (13.5% vs 17.9%; P<0.01). The total health care in-hospital economic burden of readmission was $6.5 million in total charges and $25 million in total costs. Independent predictors of readmission were major bleeding, respiratory failure requiring mechanical ventilation, peripheral parenteral nutrition, history of non-alcoholic hepato-steatosis, and prolonged length of stay. Conclusions: Readmissions after gastrectomy in patients with gastric malignancies are associated with lower in-hospital mortality yet pose a substantial economic burden on healthcare. The lower mortality might be explained by the relatively stable course and lower comorbidities of patients who become eligible for discharge after surgery. Further studies are suggested. Modifiable risk factors like malnutrition and sepsis warrant special attention to decrease readmissions and improve overall outcomes.[Table: see text]

3036 Background: The presence of HER2 expressing (HER2+) circulating tumor cells (CTCs) occurs often in metastatic breast cancer (MBC) patients (pts). We have previously showed that the ratio among CTCs expressing high level of HER2 and the total number of HER2+ CTCs (circulating HER2 ratio, cHer2 ratio) has a prognostic role in MBC patients. Here we further investigate the role of the cHER2 ratio in the process of metastatic spread. Methods: Under IRB-approved study we prospectively analyzed blood samples of patients with MBC enrolled before starting a new line of therapy. Samples were collected from pts treated at Northwestern University (Chicago, IL) between 2016 and 2020. CTCs were enumerated through CellSearch (Menarini Silicon Biosystems, Bologna, Italy) and characterized for HER2 expression using the CellSearch CXC Kit. HER2+ CTCs were divided in 3 different categories (1+,2+,3+) leaning on fluorescence intensity. Pts with <5 CTCs (stage IV indolent) were excluded from the analysis. The cHER2 ratio, defined as the sum of 2+ CTCs and 3+ CTCs divided by the total number of HER2+ CTCs, was used to split the remaining pts in 2 different cohorts: cHER2 ratio high (> 0.75) (cHER2high) and cHER2 ratio low (≤0.75) (cHER2low). The frequency of each metastatic site (i.e. liver, lung, central nervous system, bone, lymph nodes, skin/soft tissue, serosa) and the total number of different sites involved (1-7, ≤2 and >2 sites) were compared among the two sub-populations and analyzed through Fisher exact test. Results: Out of 98 pts enrolled, 77 were classified as cHER2low and 21 as cHER2high. We observed a higher frequency of oligometastatic pts (≤2 sites involved) in the cHER2high cohort (16, 76%), compared to only 29 (37%) in the cHER2low (p<0.005). Moreover, the cHER2 ratio was associated with a tropism toward specific sites of disease spread with higher incidence of liver, lung and lymph nodes metastases in the cHER2low cohort (p<0.05). No other statistical associations were observed in respect of specific organ tropism. The frequency of involvement for each metastatic site among the two cohorts are reported in the table. Conclusions: Measuring CTCs enumeration and HER2 expression we identified two cohorts, cHER2high and cHER2low, associated with distinct patterns of metastatic spread. The cHER2low pts were correlated to multiple sites of metastatic involvement, with particular tropism toward liver, lung and lymph nodes. These results confirm the prognostic role of the cHER2 ratio, suggesting a peculiar biological meaning of the HER2+ 1+ CTCs.[Table: see text]

Background and objectives In the rare disease primary hyperoxaluria type 1, overproduction of oxalate by the liver causes kidney stones, nephrocalcinosis, kidney failure, and systemic oxalosis. Lumasiran, an RNA interference therapeutic, suppresses glycolate oxidase, reducing hepatic oxalate production. The objective of this first-in-human, randomized, placebo-controlled trial was to evaluate the safety, pharmacokinetic, and pharmacodynamic profiles of lumasiran in healthy participants and patients with primary hyperoxaluria type 1. Design, setting, participants, & measurements This phase 1/2 study was conducted in two parts. In part A, healthy adults randomized 3:1 received a single subcutaneous dose of lumasiran or placebo in ascending dose groups (0.3–6 mg/kg). In part B, patients with primary hyperoxaluria type 1 randomized 3:1 received up to three doses of lumasiran or placebo in cohorts of 1 or 3 mg/kg monthly or 3 mg/kg quarterly. Patients initially assigned to placebo crossed over to lumasiran on day 85. The primary outcome was incidence of adverse events. Secondary outcomes included pharmacokinetic and pharmacodynamic parameters, including measures of oxalate in patients with primary hyperoxaluria type 1. Data were analyzed using descriptive statistics. Results Thirty-two healthy participants and 20 adult and pediatric patients with primary hyperoxaluria type 1 were enrolled. Lumasiran had an acceptable safety profile, with no serious adverse events or study discontinuations attributed to treatment. In part A, increases in mean plasma glycolate concentration, a measure of target engagement, were observed in healthy participants. In part B, patients with primary hyperoxaluria type 1 had a mean maximal reduction from baseline of 75% across dosing cohorts in 24-hour urinary oxalate excretion. All patients achieved urinary oxalate levels ≤1.5 times the upper limit of normal. Conclusions Lumasiran had an acceptable safety profile and reduced urinary oxalate excretion in all patients with primary hyperoxaluria type 1 to near-normal levels. Clinical Trial registry name and registration number: Study of Lumasiran in Healthy Adults and Patients with Primary Hyperoxaluria Type 1, NCT02706886