Human Herpesvirus-6 Reactivation and Disease Are Infrequent in Chimeric Antigen Receptor T-cell Therapy Recipients.

Human herpesvirus-6B (HHV-6B) reactivation and disease are increasingly reported after CAR-T-cell therapy (CARTx). HHV-6 reactivation in the CAR-T-cell product was recently reported, raising questions about product and patient management. Due to overlapping manifestations with immune effector cell-associated neurotoxicity syndrome, diagnosing HHV-6B encephalitis is challenging. We provide two lines of evidence assessing the incidence and outcomes of HHV-6B after CARTx. First, in a prospective study with weekly HHV-6B testing for up to 12 weeks post-infusion, HHV-6B reactivation occurred in eight of 89 participants; three had chromosomally integrated HHV-6 and were excluded, resulting in a cumulative incidence of HHV-6B reactivation of 6% (95% confidence interval (CI), 2.2-12.5%). HHV-6B detection was low level (median peak, 435 copies/mL; IQR, 164-979) and did not require therapy. Second, we retrospectively analyzed HHV-6B detection in blood and/or cerebrospinal fluid (CSF) within 12 weeks post-infusion in CARTx recipients. Of 626 patients, 24 had symptom-driven plasma testing with detection in one. Among 34 patients with CSF HHV-6 testing, one patient had possible HHV-6 encephalitis for a cumulative incidence of 0.17% (95% CI, 0.02-0.94%), although symptoms improved without treatment. Our data demonstrate that HHV-6B reactivation and disease are infrequent after CARTx. Routine HHV-6 monitoring is not warranted.

Development and validation of an automated computational approach to grade immune effector cell-associated hematotoxicity.

Hematologic toxicity frequently complicates chimeric antigen receptor (CAR) T-cell therapy, resulting in significant morbidity and mortality. In an effort to standardize reporting, the European Hematology Association (EHA) and European Society of Blood and Marrow Transplantation (EBMT) devised the immune effector cell-associated hematotoxicity (ICAHT) grading system, distinguishing between early (day 0-30) and late (after day +30) events based on neutropenia depth and duration. However, manual implementation of ICAHT grading criteria is time-consuming and susceptible to subjectivity and error. To address these challenges, we introduce a novel computational approach, utilizing the R programming language, to automate early and late ICAHT grading. Given the complexities of early ICAHT grading, we benchmarked our approach both manually and computationally in two independent cohorts totaling 1251 patients. Our computational approach offers significant implications by streamlining grading processes, reducing manual time and effort, and promoting standardization across varied clinical settings. We provide this tool to the scientific community alongside a comprehensive implementation guide, fostering its widespread adoption and enhancing reporting consistency for ICAHT.

Factors associated with long-term outcomes of CD19 CAR T-cell therapy for relapsed/refractory CLL.

High response rates have been reported after CD19-targeted chimeric antigen receptor-modified (CD19 CAR) T-cell therapy for relapsed/refractory (R/R) chronic lymphocytic leukemia (CLL), yet the factors associated with duration of response in this setting are poorly characterized. We analyzed long-term outcomes in 47 patients with R/R CLL and/or Richter transformation treated on our phase 1/2 clinical trial of CD19 CAR T-cell therapy with an updated median follow-up of 79.6 months. Median progression-free survival (PFS) was 8.9 months, and the 6-year PFS was 17.8%. Maximum standardized uptake value (hazard ratio [HR], 1.15; 95% confidence interval [CI], 1.07-1.23; P < .001) and bulky disease (≥5 cm; HR, 2.12; 95% CI, 1.06-4.26; P = .034) before lymphodepletion were associated with shorter PFS. Day +28 complete response by positron emission tomography-computed tomography (HR, 0.13; 95% CI, 0.04-0.40; P < .001), day +28 measurable residual disease (MRD) negativity by multiparameter flow cytometry (HR, 0.08; 95% CI, 0.03-0.22; P < .001), day +28 MRD negativity by next-generation sequencing (HR, 0.21; 95% CI, 0.08-0.51; P < .001), higher peak CD8+ CAR T-cell expansion (HR, 0.49; 95% CI; 0.36-0.68; P < .001), higher peak CD4+ CAR T-cell expansion (HR, 0.47; 95% CI; 0.33-0.69; P < .001), and longer CAR T-cell persistence (HR, 0.56; 95% CI, 0.44-0.72; P < .001) were associated with longer PFS. The 6-year duration of response and overall survival were 26.4% and 31.2%, respectively. CD19 CAR T-cell therapy achieved durable responses with curative potential in a subset of patients with R/R CLL. This trial was registered at www.clinicaltrials.gov as #NCT01865617.

Expectant Management of Blunt Grade III Renal Injuries: Early Discharge Outcomes From a Level I Trauma Center.

OBJECTIVES: To determine whether patients with American Association for the Surgery of Trauma (AAST) grade III blunt renal injuries discharged within 48 hours of admission have increased rates of readmission for renal-related complications compared to patients observed for over 48 hours. METHODS: Renal trauma patients from 2005 through 2020 were identified from our institutional trauma registry. Patients with AAST III blunt renal injuries who survived beyond 48 hours of admission were included. Univariable analysis was used to identify variables associated with discharge within 48 hours. Reasons for readmission were compared between patients discharged before and after 48 hours of admission. RESULTS: Of the 1751 renal trauma patients, 377 (21.5%) met inclusion criteria. Sixty-five of 377 (17.2%) AAST III injuries were discharged within 48 hours of admission. Forty (10.6%) patients required readmission, 3 in the early discharge group and 37 in the standard discharge group. No patient required readmission for renal-related complications. CONCLUSION: Patients with AAST grade III blunt renal injuries are not at increased risk for early renal-related complications if discharged within 48 hours of admission and should be considered for early discharge. The very low rate of renal-related complications for AAST III blunt renal injuries supports their categorization as "low-grade" renal trauma.

Adapting to the Era of Virtual Recruitment: Radiology Departmental Website Response to COVID-19 and Portrayal of the Resident Experience.

RATIONALE AND OBJECTIVES: The COVID-19 pandemic has transformed radiology recruitment into a virtual affair and placed an even stronger emphasis on the importance of departmental websites. In this study, we evaluate residency websites in detailing the response to COVID-19 as well as initiatives which help describe the resident experience. MATERIALS AND METHODS: Program websites for diagnostic radiology residencies listed in the 2022 Electronic Residency Application Service (ERAS) program list were evaluated for 31 criteria related to departmental response to COVID-19, online outreach, and resident wellness. RESULTS: Of 184 programs, 182 had functioning websites for review. One program was excluded from analysis as the website was almost entirely video-based. In response to COVID-19, ≤1% described resident redeployment, vaccination information, departmental response to ABR Core Exam changes, or regular administration updates. Six (3.3%) described revised read-out protocols, four (2.2%) mentioned supplementary non-clinical education, and 14 (7.7%) indicated changes to educational conferences. The majority of websites (122, 67.4%) offered an informational or tour video, while 44 (24.3%) described expectations for virtual interviewing, and 20 (11.0%) had virtual "open-houses." Departmental social media, primarily Twitter, was linked for 60 (33.1%) programs. A total of 134 (74.0%) websites described community highlights. More than a quarter mentioned meal stipends (72, 39.8%), paid sick time (54, 29.8%) and healthcare resources (57, 31.5%). Although social activities were described by 44 (24.3%) programs, some specifically indicating changes to COVID-19, formal resident mentoring (25, 13.8%) and wellness committees (28, 15.5%) were less common. These criteria were found more commonly at the largest third of residency programs (chi square, p < 0.00625). CONCLUSION: Programs rarely described work flow changes to COVID-19, and websites could improve in virtual outreach. Compared with prior literature, departmental websites have improved in describing wellness initiatives and related measures.

Resident Wellness in Radiology as Portrayed by Departmental Websites.

RATIONALE AND OBJECTIVES: Departmental websites are often the first exposure applicants have in researching programs. Websites provide information about resident education as well as infrastructure for resident wellness. For this study, we reviewed residency websites to evaluate resident wellness initiatives and extent of details available online. MATERIALS AND METHODS: Program websites for diagnostic radiology residencies listed in the 2020 ERAS program list were evaluated for 26 criteria pertaining to resident wellness. Criteria which are not radiology resident specific were also evaluated on their graduate medical education (GME) websites if unavailable on the departmental website. RESULTS: Of 189 programs, 185 (97.9%) had functioning websites for review. Book funds were mentioned by 57% (mean $3,762), and 43.5% discussed housing stipends during AIRP (mean $2,204); neither significantly correlated with program size. Retirement plan matching was present for 47.8% of programs. Almost all programs utilized night float call schedules, with relatively similar distribution of residents starting on-call duties as fall PGY2s, spring PGY2s, and starting PGY3s. Moonlighting was mentioned by 22.8% of departments. Paid wellness days were discussed in 10.8% (mean 3.1 days/year), and 37.7% described paid parental leave (mean 27.8 days/year). Less than 10% described resident mentoring, wellness committees, or non-clinical curricula. Resident retreats were mentioned by 21.6% of programs, and 11.4% described regular social activities; both were found more frequently at larger programs (chi-square analysis, p <0.00625). CONCLUSION: This study evaluated radiology residency program and GME websites for information pertaining to resident wellness. While financial and clinical information was typically present for >50% of programs, information regarding social initiatives was generally lacking and may be one area to bolster resident wellness and describe on websites.

The Impact of Delayed-Phase Imaging at Admission on the Management of Urinary Extravasation in High-Grade Renal Trauma.

PURPOSE: American Urological Association Urotrauma guidelines recommend delayed-phase imaging on presentation for all renal injuries, although data to support it are anecdotal. Forgoing delays risks unrecognized collecting system injuries. We hypothesized that renal trauma patients without admission delays have more complications from urinary extravasation. MATERIALS AND METHODS: From 2005 through 2020, 1,751 renal trauma patients were identified from our institutional trauma registry. Included patients had an estimated American Association for the Surgery of Trauma renal injury grade of III-V and a perinephric fluid collection. Propensity scores for receipt of delayed-phase imaging were calculated based on Injury Severity Score, arrival condition, admission systolic blood pressure, sex and renal injury grade. Propensity score-adjusted logistic regression was used to compare clinical outcomes between those with and without admission delays. RESULTS: Ninety (28.6%) of 315 included patients had delays on presentation. Patients without delays had higher Injury Severity Scores (29 vs 23, p=0.002), fewer isolated renal injuries (27.6% vs 38.9%, p=0.05) and lower grade renal injuries (56.9% vs 41.1% grade 3, p=0.03). After propensity score adjustment, patients with delays were more likely to undergo immediate interventions (OR 11.75, 95% CI 2.99-78.10) and interval stent placement for urinary extravasation (OR 6.86, 95% CI 1.56-47.64) without a difference in urological complications (OR 5.07, 95% CI 0.25-766.16). CONCLUSIONS: Delayed-phase imaging was associated with an increased odds of undergoing immediate and asymptomatic interval urological interventions without a difference in the odds of a complication after high-grade renal trauma. Post-trauma urinary extravasation requires further research to determine which patients require imaging and intervention.

The Pan-Omics Landscape of Renal Cell Carcinoma and Its Implication on Future Clinical Practice.

Renal cell carcinoma has traditionally been classified based on histological features. Contemporary studies have identified genomic, transcriptomic, epigenomic, and metabolomic signatures that correspond to or even transcend histological subtypes. Much remains to be learned about improving the algorithm of pan-omics integration for precision oncology, which will not only advance our understanding of RCC pathobiology and treatment response but also result in novel therapeutic opportunities. Accordingly, this review focuses on recent RCC multi-omics literature. Encouragingly, a few reports on omics integration into routinely employed prognostic risk models have shown early promise that could lay the foundation for future development of precision kidney cancer therapies. Hence, this article serves as a primer on what we have learned and how we might better realize the clinical potential of the burgeoning pan-omics data.

The Therapeutic Landscape of Renal Cell Carcinoma: From the Dark Age to the Golden Age.

Oncologic treatments for renal cell carcinoma (RCC) have undergone a major revolution in the past 2 decades, moving away from the pre-2004 Dark Age during which interleukin 2 and interferon-α were the only therapeutic options and induced treatment responses in only 5% to 10% of patients with metastatic disease. The development of anti-angiogenic tyrosine kinase inhibitors against vascular endothelial growth factor receptor 2 and inhibitors of mammalian target of rapamycin complex 1 in 2005 introduced the Modern Age with better overall and progression-free survival and a greater number of patients (30%-40%) responding to and (∼80%) benefiting from these targeted therapeutic agents. The coming of age of the immuno-oncology era with the use of immune checkpoint inhibitors (ICIs) have ushered us into the Golden Age of metastatic RCC care, in which combined administrations of two ICIs (anti-programmed cell death protein 1/programmed death-ligand 1 and anti-cytotoxic T-lymphocyte-associated protein 4 or one tyrosine kinase inhibitor plus one ICI (anti-programmed cell death protein 1/programmed death-ligand 1) have recast the treatment landscape of clear cell RCC, the most common RCC subtype, with an approximately 60% response rate and an approximately 90% disease control rate that further improves metastatic RCC survival. Exciting clinical trials are in the pipeline investigating complementary/synergistic molecular mechanisms, based on studies investigating the biology, pathology, and genomics of renal carcinoma and the respective treatment outcome. This will enable us to enter the Diamond Age of precision medicine in which a specific treatment can be tailored to the specific biological and pathologic circumstance of an individual kidney tumor to offer more effective yet less toxic therapy.

Daily Caffeine Consumption Is Associated with Decreased Incidence of Symptoms and Hemodynamic Changes During Pharmacologic Stress with Regadenoson.

Regadenoson is an adenosine A2A receptor agonist widely used as a pharmacologic stress agent for myocardial perfusion imaging. Approximately 3.4 million regadenoson pharmacologic stress tests were performed annually as of 2011. Caffeine is a competitive antagonist of all adenosine receptor subtypes; thus, caffeine is typically withheld 12-24 h before stress with regadenoson. However, the effects of daily caffeine intake on regadenoson stress are unknown. This study assessed the effects of daily caffeine intake on symptoms and hemodynamic changes during stress testing with regadenoson. Methods: Patients presenting for regadenoson stress myocardial perfusion imaging were asked their amounts of daily caffeine intake. Chart review was used to collect data on demographics, comorbidities, and use of ß-blockers. Data collected from the regadenoson stress test included symptoms, administration of aminophylline, heart rate, blood pressure, and arrhythmias. χ2 testing and ANOVA were used to analyze data divided into 3 categories of caffeine intake (<200, 200-400, and >400 mg daily). χ2 testing was used for nominal data, and unpaired t testing was used for continuous data. Results: In total, 101 patients were enrolled: 53% men and 47% women. Of the 101 patients, 89% reported caffeine intake, with 13% reporting heavy caffeine intake (>400 mg daily). The last intake of caffeine was at least 12 h before the test. During the test, 63% of patients reported symptoms, but the test was completed successfully in all patients. Compared with those who do not use caffeine, intake for caffeine users was associated with less chest pain (P = 0.0013), less aminophylline administration (P = 0.0371), lower resting and peak heart rate (P = 0.0497 and 0.0314, respectively), and lower diastolic blood pressure response (P = 0.0468). No associations were found between caffeine intake and arrhythmia or systolic blood pressure response. Conclusion: The use of regadenoson stress for myocardial perfusion imaging in caffeine consumers is very common, safe, and associated with a lower incidence of certain symptoms than in non-caffeine consumers. Specifically, caffeine intake was associated with less aminophylline use and chest pain.

Coronary angiography and percutaneous coronary intervention in cardiac arrest survivors with non-shockable rhythms and no STEMI: A systematic review.

BACKGROUND: Emergency coronary angiography (CAG) and percutaneous coronary intervention (PCI) are thought to improve outcomes in cardiac arrest (CA) survivors with ST segment elevation myocardial infarction (STEMI) and those without STEMI but likely cardiac etiology (shockable rhythms). However, the role of CAG ±â€¯PCI in OHCA survivors with non-shockable rhythms and no STEMI post-resuscitation remains unclear. METHODS: We searched Ovid/MEDLINE, Embase, Scopus, the Cochrane Central Register of Controlled Trials, Web of Science, and ClinicalTrials.gov from inception to January 2019. Two reviewers independently screened titles and abstracts of all records retrieved in the database searches and full texts of all articles selected in the title/abstract screen, with disagreements resolved by consensus. Risk of bias was assessed using the Strobe checklist. RESULTS: Fourteen out of 1174 articles met criteria for full review. Only two studies including 152 patients with confirmed non-shockable rhythms and no STEMI post resuscitation met all criteria and were analyzed. One study reported 97 patients (of 1497 in the registry) underwent CAG and 24.7% underwent PCI. The second study reported 55 patients (of 545 in the cohort) underwent CAG and acute coronary lesions were found in 16.4% but only 9.1% underwent PCI and no survival benefit was demonstrated. CONCLUSIONS: There is limited data describing the prevalence of CAD and the role of CAG ±â€¯PCI in CA survivors with non-shockable rhythms and no STEMI post-resuscitation. In the two studies meeting criteria for this systematic review, 16% of patients with non-shockable rhythms underwent PCI.

Increased type III TGF-ß receptor shedding decreases tumorigenesis through induction of epithelial-to-mesenchymal transition.

The type III TGF-ß receptor (TßRIII) is a TGF-ß co-receptor that presents ligand to the type II TGF-ß receptor to initiate signaling. TßRIII also undergoes ectodomain shedding to release a soluble form (sTßRIII) that can bind ligand, sequestering it away from cell surface receptors. We have previously identified a TßRIII extracellular mutant that has enhanced ectodomain shedding ("super shedding (SS)"-TßRIII-SS). Here, we utilize TßRIII-SS to study the balance of cell surface and soluble TßRIII in the context of lung cancer. We demonstrate that expressing TßRIII-SS in lung cancer cell models induces epithelial-to-mesenchymal transition (EMT) and that these TßRIII-SS (EMT) cells are less migratory, invasive and adhesive and more resistant to gemcitabine. Moreover, TßRIII-SS (EMT) cells exhibit decreased tumorigenicity but increased growth rate in vitro and in vivo. These studies suggest that the balance of cell surface and soluble TßRIII may regulate a dichotomous role for TßRIII during cancer progression.

aVR ST Segment Elevation: Acute STEMI or Not? Incidence of an Acute Coronary Occlusion.

BACKGROUND: Identification of ST elevation myocardial infarction (STEMI) is critical because early reperfusion can save myocardium and increase survival. ST elevation (STE) in lead augmented vector right (aVR), coexistent with multilead ST depression, was endorsed as a sign of acute occlusion of the left main or proximal left anterior descending coronary artery in the 2013 STEMI guidelines. We investigated the incidence of an acutely occluded coronary in patients presenting with STE-aVR with multilead ST depression. METHODS: STEMI activations between January 2014 and April 2018 at the University of Arizona Medical Center were identified. All electrocardiograms (ECGs) and coronary angiograms were blindly analyzed by experienced cardiologists. Among 847 STEMI activations, 99 patients (12%) were identified with STE-aVR with multilead ST depression. RESULTS: Emergent angiography was performed in 80% (79/99) of patients. Thirty-six patients (36%) presented with cardiac arrest, and 78% (28/36) underwent emergent angiography. Coronary occlusion, thought to be culprit, was identified in only 8 patients (10%), and none of those lesions were left main or left anterior descending occlusions. A total of 47 patients (59%) were found to have severe coronary disease, but most had intact distal flow. Thirty-two patients (40%) had mild to moderate or no significant disease. However, STE-aVR with multilead ST depression was associated with 31% in-hospital mortality compared with only 6.2% in a subgroup of 190 patients with STEMI without STE-aVR (p<0.00001). CONCLUSIONS: STE-aVR with multilead ST depression was associated with acutely thrombotic coronary occlusion in only 10% of patients. Routine STEMI activation in STE-aVR for emergent revascularization is not warranted, although urgent, rather than emergent, catheterization appears to be important.

Endoglin interacts with VEGFR2 to promote angiogenesis.

Endoglin, a TGF-ß coreceptor predominantly expressed in endothelial cells, plays an important role in vascular development and tumor-associated angiogenesis. However, the mechanism by which endoglin regulates angiogenesis, especially during tip cell formation, remains largely unknown. In this study, we report that endoglin promoted VEGF-induced tip cell formation. Mechanistically, endoglin interacted with VEGF receptor (VEGFR)-2 in a VEGF-dependent manner, which sustained VEGFR2 on the cell surface and prevented its degradation. Endoglin mutants deficient in the ability to interact with VEGFR2 failed to sustain VEGFR2 on the cell surface and to promote VEGF-induced tip cell formation. Further, an endoglin-targeting monoclonal antibody (mAb), TRC105, cooperated with a VEGF-A targeting mAb, bevacizumab, to inhibit VEGF signaling and tip cell formation in vitro and to inhibit tumor growth, metastasis, and tumor-associated angiogenesis in a murine tumor model. This study demonstrate a novel mechanism by which endoglin initiates and regulates VEGF-driven angiogenesis while providing a rationale for combining anti-VEGF and anti-endoglin therapy in patients with cancer.-Tian, H., Huang, J. J., Golzio, C., Gao, X., Hector-Greene, M., Katsanis, N., Blobe, G. C. Endoglin interacts with VEGFR2 to promote angiogenesis.

Atrial Appendage Thrombosis Risk Is Lower for Atrial Flutter Compared with Atrial Fibrillation.

BACKGROUND: The risk of stroke and thromboembolism in atrial fibrillation is established. However, the evidence surrounding the risk of thromboembolism in patients with atrial flutter is not as clear. We hypothesized that atrial flutter would have indicators of less risk for thromboembolism compared with atrial fibrillation on transesophageal echocardiography, thereby possibly leading to a lower stroke risk. METHODS: A retrospective review of 2225 patients undergoing transesophageal echocardiography was performed. Those with atrial fibrillation or atrial flutter were screened. Exclusion criteria were patients being treated with chronic anticoagulation, the presence of a prosthetic valve, moderate to severe mitral regurgitation or stenosis, congenital heart disease, or a history of heart transplantation. A total of 114 patients with atrial fibrillation and 55 patients with atrial flutter met the criteria and were included in the analysis. RESULTS: Twelve patients (11%) in the atrial fibrillation group had left atrial appendage thrombus versus zero patients in the atrial flutter group (P < .05). The prevalence of spontaneous echocardiography contrast was significantly higher and left atrial appendage emptying velocity was significantly lower in the atrial fibrillation group compared with the atrial flutter group (P < .001). No spontaneous contrast was seen when the left atrial appendage emptying velocity was >60 cm/sec. CONCLUSIONS: Patients with atrial flutter have a lower incidence of left atrial appendage thrombi, higher left atrial appendage emptying velocity, and less left atrial spontaneous contrast compared with patients with atrial fibrillation, suggesting a lower risk for potential arterial thromboembolism.

Prediction of Prolonged Ventilation after Coronary Artery Bypass Grafting: Data from an Artificial Neural Network.

OBJECTIVES: The need for mechanical ventilation 24 hours after coronary artery bypass grafting (CABG) is considered a morbidity by the Society of Thoracic Surgeons. The purpose of this investigation was twofold: to identify simple preoperative patient factors independently associated with prolonged ventilation and to optimize prediction and early identification of patients prone to prolonged ventilation using an artificial neural network (ANN). METHODS: Using the institutional Adult Cardiac Database, 738 patients who underwent CABG since 2005 were reviewed for preoperative factors independently associated with prolonged postoperative ventilation. Prediction of prolonged ventilation from the identified variables was modeled using both "traditional" multiple logistic regression and an ANN. The two models were compared using Pearson r2 and area under the curve (AUC) parameters. RESULTS: Of 738 included patients, 14% (104/738) required mechanical ventilation ≥ 24 hours postoperatively. Upon multivariate analysis, higher body-mass index (BMI; odds ratio [OR] 1.10 per unit, P < 0.001), lower ejection fraction (OR 0.97 per %, P = 0.01) and use of cardiopulmonary bypass (OR 2.59, P = 0.02) were independently predictive of prolonged ventilation. The Pearson r2 and AUC of the multivariate nominal logistic regression model were 0.086 and 0.698 ± 0.05, respectively; analogous statistics of the ANN model were 0.159 and 0.732 ± 0.05, respectively.BMI, ejection fraction and cardiopulmonary bypass represent three simple factors that may predict prolonged ventilation after CABG. Early identification of these patients can be optimized using an ANN, an emerging paradigm for clinical outcomes modeling that may consider complex relationships among these variables.

Dichotomous roles of TGF-ß in human cancer.

Transforming growth factor-ß (TGF-ß) mediates numerous biological processes, including embryonic development and the maintenance of cellular homeostasis in a context-dependent manner. Consistent with its central role in maintaining cellular homeostasis, inhibition of TGF-ß signaling results in disruption of normal homeostatic processes and subsequent carcinogenesis, defining the TGF-ß signaling pathway as a tumor suppressor. However, once carcinogenesis is initiated, the TGF-ß signaling pathway promotes cancer progression. This dichotomous function of the TGF-ß signaling pathway is mediated through altering effects on both the cancer cells, by inducing apoptosis and inhibiting proliferation, and the tumor microenvironment, by promoting angiogenesis and inhibiting immunosurveillance. Current studies support inhibition of TGF-ß signaling either alone, or in conjunction with anti-angiogenic therapy or immunotherapy as a promising strategy for the treatment of human cancers.

TGF-ß-induced stromal CYR61 promotes resistance to gemcitabine in pancreatic ductal adenocarcinoma through downregulation of the nucleoside transporters hENT1 and hCNT3.

Pancreatic ductal adenocarcinoma (PDAC) is a lethal cancer in part due to inherent resistance to chemotherapy, including the first-line drug gemcitabine. Although low expression of the nucleoside transporters hENT1 and hCNT3 that mediate cellular uptake of gemcitabine has been linked to gemcitabine resistance, the mechanisms regulating their expression in the PDAC tumor microenvironment are largely unknown. Here, we report that the matricellular protein cysteine-rich angiogenic inducer 61 (CYR61) negatively regulates the nucleoside transporters hENT1 and hCNT3. CRISPR/Cas9-mediated knockout of CYR61 increased expression of hENT1 and hCNT3, increased cellular uptake of gemcitabine and sensitized PDAC cells to gemcitabine-induced apoptosis. In PDAC patient samples, expression of hENT1 and hCNT3 negatively correlates with expression of CYR61 . We demonstrate that stromal pancreatic stellate cells (PSCs) are a source of CYR61 within the PDAC tumor microenvironment. Transforming growth factor-ß (TGF-ß) induces the expression of CYR61 in PSCs through canonical TGF-ß-ALK5-Smad2/3 signaling. Activation of TGF-ß signaling or expression of CYR61 in PSCs promotes resistance to gemcitabine in PDAC cells in an in vitro co-culture assay. Our results identify CYR61 as a TGF-ß-induced stromal-derived factor that regulates gemcitabine sensitivity in PDAC and suggest that targeting CYR61 may improve chemotherapy response in PDAC patients.