Targeting glutaminase is therapeutically effective in ibrutinib-resistant mantle cell lymphoma.

Mantle cell lymphoma (MCL) is an incurable B-cell non-Hodgkin lymphoma characterized by frequent relapses. The development of resistance to ibrutinib therapy remains a major challenge in MCL. We previously showed that glutaminolysis is associated with resistance to ibrutinib. In this study, we confirmed that glutaminase (GLS), the first enzyme in glutaminolysis, is overexpressed in ibrutinib-resistant MCL cells, and that its expression correlates well with elevated glutamine dependency and glutaminolysis. Furthermore, we discovered that GLS expression correlates with MYC expression and the functioning of the glutamine transporter ASCT2. Depletion of glutamine or GLS significantly reduced cell growth, while GLS overexpression enhanced glutamine dependency and ibrutinib resistance. Consistent with this, GLS inhibition by its specific inhibitor telaglenastat suppressed MCL cell growth both in vitro and in vivo. Moreover, telaglenastat showed anti-MCL synergy when combined with ibrutinib or venetoclax in vitro, which was confirmed using an MCL patient-derived xenograft model. Our study provides the first evidence that targeting GLS with telaglenastat, alone or in combination with ibrutinib or venetoclax, is a promising strategy to overcome ibrutinib resistance in MCL.

Dual targeting of PI3K and BCL-2 overcomes ibrutinib resistance in aggressive mantle cell lymphoma.

Despite significant efficacy of ibrutinib therapy in mantle cell lymphoma (MCL), about one-third of MCL patients will display primary resistance. In time, secondary resistance occurs almost universally with an unlikely response to salvage chemotherapy afterwards. While intense efforts are being directed towards the characterization of resistance mechanisms, our focus is on identifying the signalling network rewiring that characterizes this ibrutinib resistant phenotype. Importantly, intrinsic genetic, epigenetic and tumour microenvironment-initiated mechanisms have all been shown to influence the occurrence of the ibrutinib resistant phenotype. By using in vitro and in vivo models of primary and secondary ibrutinib resistance as well as post-ibrutinib treatment clinical samples, we show that dual targeting of the BCL-2 and PI3-kinase signalling pathways results in synergistic anti-tumour activity. Clinically relevant doses of venetoclax, a BCL-2 inhibitor, in combination with duvelisib, a PI3Kδ/γ dual inhibitor, resulted in significant inhibition of these compensatory pathways and apoptosis induction. Our preclinical results suggest that the combination of venetoclax and duvelisib may be a therapeutic option for MCL patients who experienced ibrutinib failure and merits careful consideration for future clinical trial evaluation.

TIGIT is the central player in T-cell suppression associated with CAR T-cell relapse in mantle cell lymphoma.

BACKGROUND: Chimeric antigen receptor (CAR) T-cell therapy using brexucabtagene autoleucel (BA) induces remission in many patients with mantle cell lymphoma (MCL), and BA is the only CAR T-cell therapy approved by the FDA for MCL. However, development of relapses to BA is recognized with poor patient outcomes. Multiple CAR T-cell therapies have been approved for other lymphomas and the resistance mechanisms have been investigated. However, the mechanisms underlying BA relapse in MCL have not been investigated and whether any previously reported resistance mechanisms apply to BA-relapsed patients with MCL is unknown. METHODS: To interrogate BA resistance mechanisms in MCL, we performed single-cell RNA sequencing on 39 longitudinally collected samples from 15 BA-treated patients, and multiplex cytokine profiling on 80 serial samples from 20 patients. RESULTS: We demonstrate that after BA relapse, the proportion of T cells, especially cytotoxic T cells (CTLs), decreased among non-tumor cells, while the proportion of myeloid cells correspondingly increased. TIGIT, LAG3, and CD96 were the predominant checkpoint molecules expressed on exhausted T cells and CTLs; only TIGIT was significantly increased after relapse. CTLs expanded during remission, and then contracted during relapse with upregulated TIGIT expression. Tumor cells also acquired TIGIT expression after relapse, leading to the enhanced interaction of tumor cell TIGIT with monocyte CD155/PVR. In myeloid cells, post-relapse HLA-II expression was reduced relative to pretreatment and during remission. Myeloid-derived suppressor cells (MDSCs) were enriched after relapse with elevated expression of activation markers, including CLU (clusterin) and VCAN (versican). Extracellular chemokines (CCL4, CXCL9, CXCL13), soluble checkpoint inhibitors (sPD-L1, sTIM3, s4-1BB), and soluble receptors (sIL-2R, sTNFRII) were decreased during remission but elevated after relapse. CONCLUSIONS: Our data demonstrate that multiple tumor-intrinsic and -extrinsic factors are associated with T-cell suppression and BA relapse. Among these, TIGIT appears to be the central player given its elevated expression after BA relapse in not only CTLs but also MCL cells. The acquisition of TIGIT expression on tumor cells is MCL-specific and has not been reported in other CAR T-treated diseases. Together, our data suggest that co-targeting TIGIT may prevent CAR T relapses and thus promote long-term progression-free survival in MCL patients.

Chronic Opioid Prescribing in Primary Care: Factors and Perspectives.

BACKGROUND: Primary care clinicians write 45% of all opioid prescriptions in the United States, but little is known about the characteristics of patients who receive them and the clinicians who prescribe opioids in primary care settings. Our study aimed to describe the patient and clinician characteristics and clinicians' perspectives of chronic opioid prescribing in primary care. METHODS: Using a mixed methods approach, we completed an analysis of 2016 electronic health records from 21 primary care practices to identify patients who had received chronic opioids, which we defined as in receipt of an opioid prescription for at least 3 consecutive months. We compared those receiving chronic opioids with those not in terms of their demographics, prescribing clinician characteristics, and risk factors for opioid-related harms, as identified by the Centers for Disease Control and Prevention Guideline on Opioid Prescribing for Chronic Pain. We then interviewed 16 primary care clinicians about their perspectives on chronic opioid prescribing. RESULTS: Of 84,029 patients, 1.1% (902/84,929) received chronic opioid prescriptions. Characteristics associated with being prescribed chronic opioids include being female, being of black or African American race, and having risks for opioid-related harms, such as mental health diagnoses, substance use disorder, and concurrent benzodiazepine use. Clinicians report multiple difficulties in weaning patients from chronic opioids, including medical contraindications of nonopioid alternatives and difficulty justifying weaning by stable long-term patients. CONCLUSION: Although patients prescribed opioids in primary care have higher risks of opioid-related harms, clinicians report multiple barriers in deprescribing chronic opioids. Future studies should examine strategies to mitigate these harms and engage patients in shared decision making about their chronic opioid use.

The CDK9 inhibitor enitociclib overcomes resistance to BTK inhibition and CAR-T therapy in mantle cell lymphoma.

Inhibitors of Bruton's tyrosine kinase (BTKi) and chimeric antigen receptor T-cell (CAR-T) therapy targeting CD19 are paradigm-shifting advances in treating patients with aggressive mantle cell lymphoma (MCL). However, clinical relapses following BTKi and CD19-directed CAR-T treatments are a fast-growing medical challenge. Development of novel therapies to overcome BTKi resistance (BTKi-R) and BTKi-CAR-T dual resistance (Dual-R) are urgently needed. Our single-cell RNA sequencing data revealed major transcriptomic reprogramming, with great enrichment of MYC-targets evolving as resistance to these therapies developed. Interestingly, cyclin-dependent kinase 9 (CDK9), a critical component of the positive transcription elongation factor-b complex, was among the top upregulated genes in Dual-R vs. BTKi-R samples. We therefore hypothesized that targeting CDK9 may turn off MYC-driven tumor survival and drug resistance. Enitociclib (formerly VIP152) is a selective CDK9 inhibitor whose potency against MCL has not been assessed. In this study, we found that enitociclib was highly potent in targeting lymphoma cells, with the half-maximal inhibitory concentration (IC50) ranging from 32 to 172 nM in MCL and diffuse large B-cell lymphoma cell lines. It inhibited CDK9 phosphorylation and downstream events including de novo synthesis of the short-lived proteins c-MYC, MCL-1, and cyclin D1, and induced apoptosis in a caspase-3-dependent manner. Enitociclib potently inhibited in vivo tumor growth of cell line-derived and patient-derived xenografts having therapeutic resistance. Our data demonstrate the potency of enitociclib in overcoming therapeutic resistance in MCL models and provide evidence in favor of its clinical investigation.

The HSP90-MYC-CDK9 network drives therapeutic resistance in mantle cell lymphoma.

Brexucabtagene autoleucel CAR-T therapy is highly efficacious in overcoming resistance to Bruton's tyrosine kinase inhibitors (BTKi) in mantle cell lymphoma. However, many patients relapse post CAR-T therapy with dismal outcomes. To dissect the underlying mechanisms of sequential resistance to BTKi and CAR-T therapy, we performed single-cell RNA sequencing analysis for 66 samples from 25 patients treated with BTKi and/or CAR-T therapy and conducted in-depth bioinformatics™ analysis. Our analysis revealed that MYC activity progressively increased with sequential resistance. HSP90AB1 (Heat shock protein 90 alpha family class B member 1), a MYC target, was identified as early driver of CAR-T resistance. CDK9 (Cyclin-dependent kinase 9), another MYC target, was significantly upregulated in Dual-R samples. Both HSP90AB1 and CDK9 expression were correlated with MYC activity levels. Pharmaceutical co-targeting of HSP90 and CDK9 synergistically diminished MYC activity, leading to potent anti-MCL activity. Collectively, our study revealed that HSP90-MYC-CDK9 network is the primary driving force of therapeutic resistance.

Potentiation of apoptosis in drug-resistant mantle cell lymphoma cells by MCL-1 inhibitor involves downregulation of inhibitor of apoptosis proteins.

Bruton's tyrosine kinase inhibitors (BTKi) and CAR T-cell therapy have demonstrated tremendous clinical benefits in mantle cell lymphoma (MCL) patients, but intrinsic or acquired resistance inevitably develops. In this study, we assessed the efficacy of the highly potent and selective MCL-1 inhibitor AZD5991 in various therapy-resistant MCL cell models. AZD5991 markedly induced apoptosis in these cells. In addition to liberating BAK from the antiapoptotic MCL-1/BAK complex for the subsequent apoptosis cascade, AZD5991 downregulated inhibitor of apoptosis proteins (IAPs) through a BAK-dependent mechanism to amplify the apoptotic signal. The combination of AZD5991 with venetoclax enhanced apoptosis and reduced mitochondrial oxygen consumption capacity in MCL cell lines irrespective of their BTKi or venetoclax sensitivity. This combination also dramatically inhibited tumor growth and prolonged mouse survival in two aggressive MCL patient-derived xenograft models. Mechanistically, the augmented cell lethality was accompanied by the synergistic suppression of IAPs. Supporting this notion, the IAP antagonist BV6 induced dramatic apoptosis in resistant MCL cells and sensitized the resistant MCL cells to venetoclax. Our study uncovered another unique route for MCL-1 inhibitor to trigger apoptosis, implying that the pro-apoptotic combination of IAP antagonists and apoptosis inducers could be further exploited for MCL patients with multiple therapeutic resistance.

Cotargeting of BTK and MALT1 overcomes resistance to BTK inhibitors in mantle cell lymphoma.

Bruton's tyrosine kinase (BTK) is a proven target in mantle cell lymphoma (MCL), an aggressive subtype of non-Hodgkin lymphoma. However, resistance to BTK inhibitors is a major clinical challenge. We here report that MALT1 is one of the top overexpressed genes in ibrutinib-resistant MCL cells, while expression of CARD11, which is upstream of MALT1, is decreased. MALT1 genetic knockout or inhibition produced dramatic defects in MCL cell growth regardless of ibrutinib sensitivity. Conversely, CARD11-knockout cells showed antitumor effects only in ibrutinib-sensitive cells, suggesting that MALT1 overexpression could drive ibrutinib resistance via bypassing BTK/CARD11 signaling. Additionally, BTK knockdown and MALT1 knockout markedly impaired MCL tumor migration and dissemination, and MALT1 pharmacological inhibition decreased MCL cell viability, adhesion, and migration by suppressing NF-κB, PI3K/AKT/mTOR, and integrin signaling. Importantly, cotargeting MALT1 with safimaltib and BTK with pirtobrutinib induced potent anti-MCL activity in ibrutinib-resistant MCL cell lines and patient-derived xenografts. Therefore, we conclude that MALT1 overexpression associates with resistance to BTK inhibitors in MCL, targeting abnormal MALT1 activity could be a promising therapeutic strategy to overcome BTK inhibitor resistance, and cotargeting of MALT1 and BTK should improve MCL treatment efficacy and durability as well as patient outcomes.

PIK-75 overcomes venetoclax resistance via blocking PI3K-AKT signaling and MCL-1 expression in mantle cell lymphoma.

Therapeutic resistance is the major challenge in clinic for patients with mantle cell lymphoma (MCL), an aggressive subtype of B-cell lymphoma. In addition to the FDA-approved Bruton's tyrosine kinase (BTK) inhibitors, multiple clinical trials have demonstrated clinical benefits in targeting BCL-2 by venetoclax and reported to greatly improve clinical outcome for refractory/relapsed patients with MCL alone or in combination with BTK inhibitors. However, resistance to venetoclax is no exception and marks as a new clinic challenge. To decode the underlying mechanisms driving venetoclax resistance, we established two MCL cell lines, Mino-Re and Rec1-Re, with acquired resistance to venetoclax from sensitive Mino and Rec-1. Using reverse phase protein assay (RPPA), an agnostic proteomic approach, we identified targetable signaling pathways that are associated with acquired venetoclax resistance in Mino-Re and Rec1-Re cells. A panel of pro-survival signals was identified to correlate well with venetoclax-resistance, including increased expression of MCL-1, BCL-xL and AKT phosphorylation, and decreased expression of BIM, BAX and PTEN. Based on a high throughput drug screening of over 320 FDA-approved/investigational drugs in the paired venetoclax-sensitive and -resistant cell lines Mino-Re and Rec1-Re, we identified the top candidates that are capable to overcome acquired venetoclax resistance in these cells. The best candidate is PIK-75, a dual inhibitor targeting both PI3K and CDK9. Its action to overcome venetoclax resistance was further confirmed in additional cell lines with primary venetoclax resistance (n=4) and primary patient samples (n=21). Mechanistically, PIK75 treatment potently diminished the elevated MCL-1 expression and AKT activation in cells with acquired or primary venetoclax resistance and resulted in potent anti-MCL activity to overcome these resistances. In addition, PIK75 is also potent in overcoming tumor microenvironment (TME)-associated venetoclax resistance. Furthermore, PIK-75 treatment is efficacious in overcoming primary and acquired venetoclax resistance in xenograft models and inhibited tumor cell dissemination to spleen in mice. Altogether, our data demonstrated that PIK-75 is highly potent in overcoming primary, acquired, or stromal cells-induced venetoclax resistances in MCL cells and revealed a new tumor vulnerability that can be exploited clinically in difficult to treat MCL cases, especially those with venetoclax resistance.

Targeting FcγRIIB by antagonistic antibody BI-1206 improves the efficacy of rituximab-based therapies in aggressive mantle cell lymphoma.

Inevitable relapses remain as the major therapeutic challenge in patients with mantle cell lymphoma (MCL) despite FDA approval of multiple targeted therapies and immunotherapies. Fc gamma receptors (FcγRs) play important roles in regulating antibody-mediated immunity. FcγRIIB, the unique immune-checkpoint inhibitory member of the FcγR family, has been implicated in immune cell desensitization and tumor cell resistance to the anti-CD20 antibody rituximab and other antibody-mediated immunotherapies; however, little is known about its expression and its immune-modulatory function in patients with aggressive MCL, especially those with multi-resistance. In this study, we found that FcγRIIB was ubiquitously expressed in both MCL cell lines and primary patient samples. FcγRIIB expression is significantly higher in CAR T-relapsed patient samples (p < 0.0001) compared to ibrutinib/rituximab-naïve, sensitive or resistant samples. Rituximab-induced CD20 internalization in JeKo-1 cells was completely blocked by concurrent treatment with BI-1206, a recombinant human monoclonal antibody targeting FcγRIIB. Combinational therapies with rituximab-ibrutinib, rituximab-venetoclax and rituximab-CHOP also induced CD20 internalization which was again effectively blocked by BI-1206. BI-1206 significantly enhanced the in vivo anti-MCL efficacy of rituximab-ibrutinib (p = 0.05) and rituximab-venetoclax (p = 0.02), but not the rituximab-CHOP combination in JeKo-1 cell line-derived xenograft models. In patient-derived xenograft (PDX) models, BI-1206, as a single agent, showed high potency (p < 0.0001, compared to vehicle control) in one aggressive PDX model that is resistant to both ibrutinib and venetoclax but sensitive to the combination of rituximab and lenalidomide (the preclinical mimetic of R2 therapy). BI-1206 sensitized the efficacy of rituximab monotherapy in a PDX model with triple resistance to rituximab, ibrutinib and CAR T-therapies (p = 0.030). Moreover, BI-1206 significantly enhanced the efficacy of the rituximab-venetoclax combination (p < 0.05), which led to long-term tumor remission in 25% of mice. Altogether, these data support that targeting this new immune-checkpoint blockade enhances the therapeutic activity of rituximab-based regimens in aggressive MCL models with multi-resistance.

United States Family Medicine research collaborations associated with higher citation and funding rates.

INTRODUCTION Among academic medical disciplines, Family Medicine (FM) research is notable for its breadth of health-care content areas, making it particularly susceptible to interdisciplinary collaboration. AIM This study characterises the degree and typology of such collaborations, and determines whether collaboration patterns are associated with citation frequency and funding. METHODS This cross-sectional study describes collaboration patterns for publications from 2015 indexed in Web of Science and authored by faculty from United States (US) departments of family medicine (DFMs). We determined mean number of total and FM authors per publication, and percentage of publications with FM first or last authors. Publications were categorised by inclusion of non-FM faculty author(s) and number of DFMs represented. RESULTS Overall, 919 FM faculty from 109 DFMs authored a total of 1872 unique publications in 2015. There was an average of 6.8 authors per publication with 1.4 authors being FM faculty. FM faculty were first author on 26.2% and last author on 29.2% of publications. Of all publications, 0.9% were single FM Author; 1.0% were same DFM; 0.3% were multiple DFMs; 72.4% were single FM Author+non-FM; 19.3% were same DFM+non-FM; 6.0% were multiple DFMs+non-FM. FM publications with non-FM faculty authors showed higher citation rates, higher rates of funding, and lower rates of having no funding source. DISCUSSION Most FM publications involved non-FM faculty authors. Collaborations involving non-FM authors were correlated with higher impact publications and projects that were more likely to have been funded.

The antibody drug conjugate VLS-101 targeting ROR1 is effective in CAR T-resistant mantle cell lymphoma.

Mantle cell lymphoma (MCL) is a rare, aggressive and incurable subtype of non-Hodgkin's B-cell lymphoma. The principal barrier is frequent clinical relapse to multiple lines of therapies, including new FDA-approved biologics and cell therapy. Brexucabtagene autoleucel, the first and only FDA approved chimeric antigen receptor (CAR) T product in MCL, demonstrated unprecedented efficacy in overcoming resistance to Bruton's tyrosine kinase inhibitors. However, relapses have inevitably occurred and once relapsed these patients display a very poor clinical outcome. Currently, there is no optional therapy specifically designed for these patients. The development of tailored and more efficacious therapies is therefore critical and represents a new medical need. We found that while the receptor tyrosine kinase-like orphan receptor 1 (ROR1) is expressed across most of the MCL cells, it is significantly elevated in CAR T-relapsed MCL tumors. To see whether this aberrant ROR1 expression contributed to CAR T resistance, we targeted ROR1 using VLS-101, a monomethyl auristatin E conjugated anti-ROR1 antibody. VLS-101 showed potent anti-MCL activity in vitro in ROR1-expressing MCL cell lines and ex vivo in primary patient samples. Importantly, VLS-101 safely induced tumor regression in PDX models resistant to CAR T-cell therapy, ibrutinib and/or venetoclax. These data advocate for targeting ROR1 as a viable approach in the treatment of ROR1-positive MCL tumors, especially those with failure to prior therapies. These data also provide strong evidence for future enrollment of post-CD19 CAR T-cell relapsed MCL patients in a first in-human phase 1b VLS-101 trial. The upcoming testing in a clinical setting will provide important insights on this new therapeutic development aiming to overcome the CAR T resistance via targeting ROR1, which is a rising unmet clinical need in MCL.

Uptake of Statin Guidelines to Prevent and Treat Cardiovascular Disease.

INTRODUCTION: In December 2013, cholesterol treatment guidelines changed the approach to statin therapy by recommending fixed doses of low-, medium-, or high-intensity statins based on cardiovascular risk. We sought to evaluate the guideline's adoption in a diverse group of practices. METHODS: Using a mixed-methods approach, we analyzed electronic health record data the year before and 2 years following guideline publication in 45 practices across 8 states. We examined associations based on patient, clinician, and practice characteristics and interviewed 24 clinicians and practice leaders to inform findings. RESULTS: The proportion of patients adherent with all recommendations 2 years after the guideline only increased from 18.5% to 20.3% (P < .01). There were clinically insignificant increases in statin use across risk strata (1.7% to 3.5%) and small increases in high-intensity statin use (2.6% to 4.6%). Only half of patients with cardiovascular disease (52.9%) were on any statin, not much different from patients at moderate (49.6% to 50.9%) or low (41.6% to 48.7%) risk. Multiple patient (risk, use of health care), clinician (age), and practice (type, rurality) factors were associated with statin use. Clinicians reported patient resistance to statins but liked having a risk calculator to guide discussions. CONCLUSION: Despite general agreement with statin benefit, the guideline was poorly implemented. Marginal differences in statin use between the highest and lower risk strata of patients is concerning. Rather than intensifying statin potency and recommending more patients take statins, guidelines may want to focus on ensuring that those who will benefit most get treatment.

Inhibition of B-cell receptor signaling disrupts cell adhesion in mantle cell lymphoma via RAC2.

Inhibition of the B-cell receptor (BCR) signaling pathway is highly effective in B-cell neoplasia through Bruton tyrosine kinase inhibition by ibrutinib. Ibrutinib also disrupts cell adhesion between a tumor and its microenvironment. However, it is largely unknown how BCR signaling is linked to cell adhesion. We observed that intrinsic sensitivities of mantle cell lymphoma (MCL) cell lines to ibrutinib correlated well with their cell adhesion phenotype. RNA-sequencing revealed that BCR and cell adhesion signatures were simultaneously downregulated by ibrutinib in the ibrutinib-sensitive, but not ibrutinib-resistant, cells. Among the differentially expressed genes, RAC2, part of the BCR signature and a known regulator of cell adhesion, was downregulated at both the RNA and protein levels by ibrutinib only in sensitive cells. RAC2 physically associated with B-cell linker protein (BLNK), a BCR adaptor molecule, uniquely in sensitive cells. RAC2 reduction using RNA interference and CRISPR impaired cell adhesion, whereas RAC2 overexpression reversed ibrutinib-induced cell adhesion impairment. In a xenograft mouse model, mice treated with ibrutinib exhibited slower tumor growth, with reduced RAC2 expression in tissue. Finally, RAC2 was expressed in ∼65% of human primary MCL tumors, and RAC2 suppression by ibrutinib resulted in cell adhesion impairment. These findings, made with cell lines, a xenograft model, and human primary lymphoma tumors, uncover a novel link between BCR signaling and cell adhesion. This study highlights the importance of RAC2 and cell adhesion in MCL pathogenesis and drug development.

Longitudinal single-cell profiling reveals molecular heterogeneity and tumor-immune evolution in refractory mantle cell lymphoma.

The mechanisms driving therapeutic resistance and poor outcomes of mantle cell lymphoma (MCL) are incompletely understood. We characterize the cellular and molecular heterogeneity within and across patients and delineate the dynamic evolution of tumor and immune cell compartments at single cell resolution in longitudinal specimens from ibrutinib-sensitive patients and non-responders. Temporal activation of multiple cancer hallmark pathways and acquisition of 17q are observed in a refractory MCL. Multi-platform validation is performed at genomic and cellular levels in PDX models and larger patient cohorts. We demonstrate that due to 17q gain, BIRC5/survivin expression is upregulated in resistant MCL tumor cells and targeting BIRC5 results in marked tumor inhibition in preclinical models. In addition, we discover notable differences in the tumor microenvironment including progressive dampening of CD8+ T cells and aberrant cell-to-cell communication networks in refractory MCLs. This study reveals diverse and dynamic tumor and immune programs underlying therapy resistance in MCL.

Factors Influencing Uptake of Changes to Clinical Preventive Guidelines.

BACKGROUND: Despite widespread recognition that adherence to clinical preventive guidelines improves patient outcomes, clinicians struggle to implement guideline changes in a timely manner. Multiple factors influence guideline adoption and effective implementation. However, few studies evaluate their collective and inter-related effects. This qualitative study provides a comprehensive picture of the interplay between multiple factors on uptake of new or changed preventive guidelines. METHODS: Semistructured interviews conducted in 2018 with a diverse sample of clinicians and practice leaders sought to understand patient, clinician, practice, health system, environment, and guideline factors of influence. An immersion-crystallization approach was used to identify emergent themes. RESULTS: Interviewees expressed motivation to adhere to guidelines but also valued sharing decisions with patients. Personal biases and fears affected both clinician and patient guideline adoption. Practices facilitated implementation through workflow optimization and encouraging a culture of evidence-based practice while a key health system function was to maintain electronic health record alerts. More traditional environmental factors, such as insurance coverage or transportation, were less of a barrier to guideline adoption and implementation than the influence of media and specialists. Various specific guideline characteristics also affected ease of adoption and implementation. Different settings expressed greater health system, practice, or clinician-centric approaches to guideline implementation. CONCLUSIONS: Guideline uptake is influenced by a complex interplay of multiple levels of factors including the patient, clinician, practice, health system, environment, and guideline levels. Comprehensively understanding all levels of influence for each specific clinical setting may help to determine the optimal intervention(s) for improving uptake of evidence-based guidelines.

Haploinsufficiency for p190B RhoGAP inhibits MMTV-Neu tumor progression.

INTRODUCTION: Rho signaling regulates key cellular processes including proliferation, survival, and migration, and it has been implicated in the development of many types of cancer including breast cancer. P190B Rho GTPase activating protein (RhoGAP) functions as a major inhibitor of the Rho GTPases. P190B is required for mammary gland morphogenesis, and overexpression of p190B in the mammary gland induces hyperplastic lesions. Hence, we hypothesized that p190B may play a pivotal role in mammary tumorigenesis. METHODS: To investigate the effects of loss of p190B function on mammary tumor progression, p190B heterozygous mice were crossed with an MMTV-Neu breast cancer model. Effects of p190B deficiency on tumor latency, multiplicity, growth, preneoplastic progression and metastasis were evaluated. To investigate potential differences in tumor angiogenesis between the two groups, immunohistochemistry to detect von Willebrand factor was performed and quantified. To examine gene expression of potential mediators of the angiogenic switch, an angiogenesis PCR array was utilized and results were confirmed using immunohistochemistry. Finally, reciprocal transplantation of tumor fragments was performed to determine the impact of stromal deficiency of p190B on tumor angiogenesis. RESULTS: P190B deficiency reduced tumor penetrance (53% of p190B+/-Neu mice vs. 100% of p190B+/+Neu mice formed tumors) and markedly delayed tumor onset by an average of 46 weeks. Tumor multiplicity was also decreased, but an increase in the number of preneoplastic lesions was detected indicating that p190B deficiency inhibited preneoplastic progression. Angiogenesis was decreased in the p190B heterozygous tumors, and expression of a potent angiogenic inhibitor, thrombospondin-1, was elevated in p190B+/-Neu mammary glands. Transplantation of p190B+/-Neu tumor fragments into wild-type recipients restored tumor angiogenesis. Strikingly, p190B+/+Neu tumor fragments were unable to grow when transplanted into p190B+/-Neu recipients. CONCLUSIONS: These data suggest that p190B haploinsufficiency in the epithelium inhibits MMTV-Neu tumor initiation. Furthermore, p190B deficiency in the vasculature is responsible, in part, for the inhibition of MMTV-Neu tumor progression.

The Scholarly Output of Faculty in Family Medicine Departments.

BACKGROUND AND OBJECTIVES: While prior efforts have assessed the scope of family medicine research, the methods have differed, and the efforts have not been routinely repeated. The purpose of this analysis was to quantify publications, journals, citations, and funding of US family medicine faculty and identify factors associated with these outcomes. METHODS: We identified faculty in US departments of family medicine through website searches and performed a cross-sectional study. We included 2015 publications in peer-reviewed journals indexed in Web of Science (a database that aggregates a wide range of catalogs). We calculated descriptive statistics assessing the publications, journals, and citations for family medicine faculty. We conducted bivariate analyses by department region, department size, public/private status, faculty title, and faculty degree. RESULTS: We identified 6,738 faculty at 134 departments, with 15% of faculty having any publications. Family medicine faculty published 3,002 times (mean of 2.9 among those with any publications). The mean number of publications was highest for faculty in departments in the West (3.7), in the third quartile for size (3.6), with a professor title (4.0), and with combined MD or DO/PhD degrees (4.3). Faculty published 84% of the time in non-family medicine journals and were cited 13,548 times. Faculty listed federal funding for over half (52%) of the times they published. CONCLUSIONS: Publications from family medicine faculty are not concentrated in family medicine journals and are being referenced by others. These figures are larger than prior estimates and should be tracked over time.

Supporting Family Medicine Research Capacity: The Critical Role and Current Contributions of US Family Medicine Organizations.

BACKGROUND AND OBJECTIVES: Family medicine is continuously advanced by a reinforcing research enterprise. In the United States, each national family medicine organization contributes to the discipline's research foundations. We sought to map the unique and interorganizational roles of the eight US family medicine professional organizations participating in Family Medicine for America's Health (FMAHealth) in supporting family medicine research. METHODS: We interviewed leaders and reviewed supporting materials from organizations participating in FMAHealth. We explored existing activities, capacity, and collaboration. We identified areas of strength and opportunities for growth and synergy with respect to how the family of family medicine nurtures family medicine research. RESULTS: The FMAHealth organizations support certain aspects of the family medicine research infrastructure. Six domains were identified through this work: showcasing scholarship, communication and dissemination, workforce development, data-driven initiatives, performing primary research, and advocacy for family medicine research. Each organization's areas of emphasis differ, but we found substantial collaboration on initiatives across organizations, possibly attributable to the fact that many members belong to more than one organization. CONCLUSIONS: Deliberate contributions to each of the six domains identified herein will be important for the future success of family medicine research. Key opportunity areas described here include coordinated and strategic advocacy for increased funding for family medicine research, dedicated investment in training opportunities, protected effort to grow the next generation of family medicine researchers, pilot funding to build a research base for future high-impact research, and infrastructure to facilitate cross-institutional collaboration and data sharing.