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Lowy, A. M.

Publications and source records attributed to Lowy, A. M..

17 recordsLinked to original sources

CA19-9 induces microenvironment remodeling in pancreatic ductal adenocarcinoma

Durable therapeutic efficacy remains a major barrier to improving outcomes for patients with pancreatic ductal adenocarcinoma (PDAC). An immunosuppressive tumor microenvironment (TME) is a hallmark of PDAC and has been demonstrated to be a dominant driver of therapeutic resistance. The aberrant glycan CA19-9 is prevalent in PDAC and drives tumor progression, but the paracrine mechanisms by which it contributes to TME remodeling are unknown. To address this, we mapped TME changes and performed functional analyses using a genetically engineered mouse model (GEMM) harboring KrasG12D mutation and inducible CA19-9 expression. Elevation of CA19-9 led to expansion of antigen-presenting cancer associated fibroblasts (apCAFs) and regulatory T cells (Tregs), which can drive immunosuppression. Antibody blockade of CA19 -9 resulted in significant restoration of normal histology and decreased apCAF and Treg populations. We dissected the paracrine signaling mechanisms that drive this TME remodeling in vitro using mouse and human organoid mono- and co-culture models as well as in vivo using GEMMs and syngeneic orthotopic transplantation models. CA19-9 induced IL1a and TGFb expression, reprogramming pancreatic mesothelial cells into apCAFs in vitro, which in turn directly ligated naive Cd4+ T cells resulting in Treg differentiation in co-cultures. Antibody blockade of IL1a and TGFb in mice led to reduced apCAF and Treg differentiation. We previously reported that CA19-9 modification of the secreted Fbln3 protein increased Egfr engagement and now find that the induction of IL1a and TGFb expression by CA19-9 is dependent on Fbln3 hyperactivation of EGFR signaling. Genetic depletion of Fbln3 led to reduced tumor progression and increased Cd8+ T cell infiltration in mice. Together these findings identify a previously unknown signaling axis driving immunosuppressive phenotypes in PDAC, uncovering multiple potential nodes to relieve the immunosuppressive pressures within the PDAC TME.

cancer biology↗

HDAC Inhibition Sensitizes Pancreatic Tumors to DNA Damage by Global Redistribution of the Transcriptional Machinery

The DNA damage response (DDR) is critical for pancreatic ductal adenocarcinoma (PDAC) development and therapeutic responses, including to genotoxic agents. While epigenetic modulators have been shown to contribute to the DDR, how chromatin regulation dictates responses to DNA damage in PDAC remains incompletely understood. Here, we identify Class I histone deacetylases (HDACs) as critical regulators of the DDR. HDAC1/2 directs the genomic distribution of H3K27ac, ensuring sufficient BRD4 and RNA polymerase II (Pol II) occupancy at DDR gene promoters. HDAC inhibition by entinostat shifts the balance of H3K27 acetylation preferentially towards intergenic regions, diverting BRD4 and Pol II from promoters, thereby suppressing DDR gene expression. In line with this, HDAC inhibition heightens DNA damage and sensitizes PDAC to diverse DNA-damaging and DDR-targeting agents. Since the clinical development of HDAC inhibitors has been limited by systemic toxicity, we developed bottlebrush prodrug (BPD) nanoparticles for tumor-selective entinostat delivery. Entinostat-BPD achieved tumor-specific HDAC inhibition while displaying potent efficacy and reduced systemic toxicity. These findings reveal an HDAC-dependent DDR vulnerability and offer combinational and precision targeting strategies to facilitate clinical translation and improve PDAC patient outcomes. SIGNIFICANCE STATEMENTThe ability of tumor cells to tolerate DNA damage limits the efficacy of many anticancer therapies. Our study reveals that pancreatic cancer cells enforce this resistance by sustaining expression of DNA damage response (DDR) genes through Class I histone deacetylases (HDACs). HDACs maintain genome-wide acetylation patterns required for efficient recruitment of the transcriptional machinery to DDR genes. Pharmacological HDAC inhibition disrupts this process and sensitizes pancreatic cancer cells to diverse DNA-damaging agents. To overcome systemic toxicity that limits translational potential, we further establish a bottlebrush prodrug nanoparticle platform that enables tumor-selective HDAC inhibition. Given the central role of the DDR in cancer, targeting HDAC-mediated DDR regulation through drug combinations and precision delivery may have broad therapeutic relevance across cancer types.

cancer biology↗

Metabolic Salvage and Acyl-chain Remodeling Support Glycosphingolipid Synthesis with the PDAC Tumor Microenvironment

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignancy where metabolic homeostasis is maintained by tumor and stromal cells within the tumor microenvironment (TME). To better assess pathways supporting macromolecule biosynthesis in PDAC tumors, we apply 13C metabolic flux analysis (MFA) to slice cultures of treatment-naive human tumors and mouse models that retain the native TME. Glycans, lipid headgroups, and very long-chain fatty acids are the most dynamic metabolic pools, while long chain fatty acids, purines, and pyrimidines are predominantly salvaged locally in situ. We use targeted pharmacological modulators to highlight the importance of recycling pathways and metabolic redundancies which mitigate changes in lipid abundances. Finally, we leverage targeted lipid fluxomics and the distinct ganglioside and globoside profiles of tumor and stromal cells, respectively, to demonstrate the role of the lipid kinase PIKfyve in supporting ganglioside homeostasis via sialic acid and ceramide salvage. These data establish application of MFA to slice cultures of PDAC tumors as an effective approach for assessing metabolic mechanisms and therapeutic responses within an intact TME.

cancer biology↗

CA19-9 promotes liver metastasis of pancreatic cancer through E-selectin mediated extravasation

Pancreatic ductal adenocarcinoma (PDAC) frequently metastasizes to the liver, which drives patient mortality. CA19-9 is elevated in most PDAC tumors and is widely used as a clinical biomarker. Elevated serum levels are associated with poor outcomes. However, whether CA19-9 functionally contributes to metastatic progression has not been fully defined, in part because mice lack endogenous CA19-9 expression. Here, using syngeneic murine PDAC cells engineered to express CA19-9, we investigated its functional role in liver metastasis. In splenic injection models, CA19-9 expression markedly increased liver metastatic burden by promoting both metastatic seeding and subsequent metastatic outgrowth. In vitro, CA19-9 enhanced tumor cell adhesion to endothelial cells through interaction with E-selectin. Metastatic seeding of CA19-9-expressing cells was reduced by genetic deletion of E-selectin or antibody neutralization of either CA19-9 or E-selectin in vivo. Therapeutic targeting of CA19-9 with a neutralizing antibody markedly reduced liver metastatic burden after metastatic seeding. CA19-9 expression increased AKT signaling in PDAC cells and liver metastases, and CA19-9 levels correlated with AKT activation in human PDAC tissues. These findings show that CA19-9 promotes PDAC liver metastasis through E-selectin-dependent metastatic seeding and AKT-associated metastatic outgrowth, highlighting CA19-9 as a functional mediator of PDAC metastasis and a potential therapeutic target.

cancer biology↗

Fatty acid scavenging enables cancer escape from KRAS inhibition

Although inhibitors of oncogenic KRAS have shown clinical efficacy1, resistance to KRAS inhibition is common2, and its molecular basis remains unclear. Here we show that KRASi-resistant cancer cells sustain mitochondrial bioenergetics through enhanced fatty acid (FA) metabolism, despite suppression of canonical KRAS signaling. Specifically, KRASi-resistant pancreatic cancer cells exploit macropinocytosis to scavenge FA released from adipose tissue, fueling beta-oxidation independently of KRAS-PI3K signaling. This adaptive metabolic program is driven by the adhesion G protein-coupled receptor ADGRB1, which activates non-canonical PI3K{gamma}-PAK1 signaling to stimulate macropinocytosis and maintain metabolic homeostasis under KRASi. Disruption of ADGRB1-PI3K{gamma} signaling dismantles this metabolic program and restores KRASi sensitivity. This pathway operates across multiple KRAS-mutated cancers and is associated with poor therapeutic response and outcome. These findings offer a promising strategy for overcoming KRASi resistance.

cancer biology↗

Leveraging autophagy and pyrimidine metabolism to target pancreatic cancer

Autophagy inhibitors are promising compounds to treat pancreatic ductal adenocarcinoma (PDA) but their efficacy in patients is unclear, highlighting a need to understand mechanisms of resistance. We used a novel approach to uncover metabolic adaptations that bypass autophagy inhibition. Utilizing PDA cells with acquired resistance to different autophagy inhibitors, we found that severe autophagy depletion induces metabolic rewiring to sustain TCA intermediates and nucleotides for biosynthesis. Long-term autophagy inhibition results in altered pyruvate metabolism likely regulated by lower pyrimidine pools. Cells adapting to loss of autophagy preferentially salvage pyrimidines to replenish these pools instead of synthesizing them de novo. Exploiting this metabolic vulnerability, we found that acquired resistance to autophagy inhibition promotes increased salvage and therefore sensitivity to pyrimidine analogues, including gemcitabine and trifluridine/tipiracil leading to combinatory effects with autophagy inhibitors and pyrimidine analogs. These studies provide mechanistic insight defining how autophagy inhibition can be leveraged to treat pancreatic cancer.

cancer biology↗

SUMO Inhibition Plus CD40 Agonism Increases Anti-Tumor Immunogenicity Through Interferon Mediated Macrophage Activation

Resistance to immunotherapy is a cardinal feature of pancreatic ductal adenocarcinoma (PDAC). Inhibition of Small Ubiquitin-like MOdifier (SUMO), a post-translational modification with important immune regulatory functions, augments responsiveness to immunotherapy in non-PDAC models via pro-immunogenic effects on myeloid cells, cancer cells, and T-cells. Recently, it has been reported that SUMO inhibition has direct immunogenic effects on PDAC. Here, we report that the novel combination of SUMO inhibition with a small molecule, TAK-981, plus antibody-mediated CD40 agonism improves survival in an aggressive orthotopic mouse model of PDAC by enhancing anti-tumoral immunogenicity. This combination amplifies CD8+ T-cell tumor infiltration and induces significant changes among macrophages. TAK-981 also leads to enhanced cancer specific MHC-I expression both in vitro and in vivo by augmenting interferon signaling. We show that the improvement in survival is mediated by macrophages. Our findings show that SUMO inhibition complements CD40 agonism to enhance immune activity in PDAC via interferon signaling, improving survival in an aggressive pre-clinical model of PDAC and translating previous findings to a characteristically immunosuppressive and highly aggressive solid malignancy.

cancer biology↗

Macropinocytosis controls metabolic stress-driven CAF subtype identity in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) tumors are deficient in glutamine, an amino acid that tumor cells and CAFs use to sustain their fitness. In PDAC, both cell types stimulate macropinocytosis as an adaptive response to glutamine depletion. CAFs play a critical role in sculpting the tumor microenvironment, yet how adaptations to metabolic stress impact the stromal architecture remains elusive. In this study, we find that macropinocytosis functions to control CAF subtype identity when glutamine is limiting. Our data demonstrate that metabolic stress leads to an intrinsic inflammatory CAF (iCAF) program driven by MEK/ERK signaling. Utilizing in vivo models, we find that blocking macropinocytosis alters CAF subtypes and reorganizes the tumor stroma. Importantly, these changes in stromal architecture can be exploited to sensitize PDAC to immunotherapy and chemotherapy. Our findings demonstrate that metabolic stress plays a role in shaping the tumor microenvironment, and that this attribute can be harnessed for therapeutic impact. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=173 SRC="FIGDIR/small/625709v1_ufig1.gif" ALT="Figure 1"> View larger version (32K): org.highwire.dtl.DTLVardef@40b38eorg.highwire.dtl.DTLVardef@1cc6a3borg.highwire.dtl.DTLVardef@15283e8org.highwire.dtl.DTLVardef@5214d2_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

MICAL2 Is a Super Enhancer Associated Gene that Promotes Pancreatic Cancer Growth and Metastasis

Pancreatic ductal adenocarcinoma (PDAC) remains one of the deadliest solid cancers and thus identifying more effective therapies is a major unmet need. In this study we characterized the super enhancer (SE) landscape of human PDAC to identify novel, potentially targetable, drivers of the disease. Our analysis revealed that MICAL2 is a super enhancer-associated gene in human PDAC. MICAL2 is a flavin monooxygenase that induces actin depolymerization and indirectly promotes SRF transcription by modulating the availability of serum response factor coactivators myocardin related transcription factors (MRTF-A and MRTF-B). We found that MICAL2 is overexpressed in PDAC and correlates with poor patient prognosis. Transcriptional analysis revealed that MICAL2 upregulates KRAS and EMT signaling pathways, contributing to tumor growth and metastasis. In loss and gain of function experiments in human and mouse PDAC cells, we observed that MICAL2 promotes both ERK1/2 and AKT activation. Consistent with its role in actin depolymerization and KRAS signaling, loss of MICAL2 expression also inhibited macropinocytosis. Through in vitro phenotypic analyses, we show that MICAL2, MRTF-A and MRTF-B influence PDAC cell proliferation, migration and promote cell cycle progression. Importantly, we demonstrate that MICAL2 is essential for in vivo tumor growth and metastasis. Interestingly, we find that MRTF-B, but not MRTF-A, phenocopies MICAL2-driven phenotypes in vivo. This study highlights the multiple ways in which MICAL2 impacts PDAC biology and suggests that its inhibition may impede PDAC progression. Our results provide a foundation for future investigations into the role of MICAL2 in PDAC and its potential as a target for therapeutic intervention.

cancer biology↗

ZBTB11 Depletion Targets Metabolic Vulnerabilities in K-Ras Inhibitor Resistant PDAC

Over 95% of pancreatic ductal adenocarcinomas (PDAC) harbor oncogenic mutations in K-Ras. Upon treatment with K-Ras inhibitors, PDAC cancer cells undergo metabolic reprogramming towards an oxidative phosphorylation-dependent, drug-resistant state. However, direct inhibition of complex I is poorly tolerated in patients due to on-target induction of peripheral neuropathy. In this work, we develop molecular glue degraders against ZBTB11, a C2H2 zinc finger transcription factor that regulates the nuclear transcription of components of the mitoribosome and electron transport chain. Our ZBTB11 degraders leverage the differences in demand for biogenesis of mitochondrial components between human neurons and rapidly-dividing pancreatic cancer cells, to selectively target the K-Ras inhibitor resistant state in PDAC. Combination treatment of both K-Ras inhibitor-resistant cell lines and multidrug resistant patient-derived organoids resulted in superior anti-cancer activity compared to single agent treatment, while sparing hiPSC-derived neurons. Proteomic and stable isotope tracing studies revealed mitoribosome depletion and impairment of the TCA cycle as key events that mediate this response. Together, this work validates ZBTB11 as a vulnerability in K-Ras inhibitor-resistant PDAC and provides a suite of molecular glue degrader tool compounds to investigate its function.

cancer biology↗

Bone Morphogenetic Protein (BMP) signaling upregulates expression of the E protein repressors, ID1 and ID3, in pancreatitis and pancreatic ductal adenocarcinoma

Identification of biological modulators of pancreatic ductal adenocarcinoma (PDAC) initiation and progression is of critical importance as it remains one of the deadliest cancers. We have previously shown that ID1 and ID3 are highly expressed in human PDAC and function to repress expression of E47 target genes involved in acinar cell differentiation and quiescence. Here, mining of large bulk RNA-seq and single cell RNA-seq (scRNA-seq) datasets has associated high expression of ID1 and ID3 with poor PDAC patient survival. We show that upregulated expression of ID1 and ID3 in human PDAC cells occurs in response to canonical BMP signaling through pSMAD1/5/9. Conversely, treatment with Noggin, an endogenous BMP antagonist, or with DMH1 and LDN193189, small molecule inhibitors of BMP receptors, reduced expression of ID1, ID3 and cell cycle control genes. Based on our RNA-seq and immunohistochemical analyses, upregulation of BMP signaling to ID1 and ID3 is an early event that occurs in human pancreatic intraepithelial neoplasia (PanIN) and murine models of pre-neoplastic lesions induced by mutant Kras. Strikingly, the same result was observed in a murine model of pancreatitis induced by the cholecystokinin (CCK) analog caerulein. Moreover, we show that caerulein is sufficient to induce BMP signaling and expression of ID1 and ID3 in a cell-autonomous manner in non-transformed rodent exocrine pancreas cells. Together, the data suggest that canonical BMP signaling upregulates expression of ID1 and ID3 early in pancreas pathogenesis and that pancreatic cancer cells remain addicted to this important signaling circuit as the disease progresses. Future exploration of druggable targets within this pathway could be of therapeutic benefit in the treatment of pancreatitis and PDAC.

cancer biology↗

A pancreatic cancer mouse model with human immunity

Pancreatic ductal adenocarcinoma (PDAC) is characterized by a tumor immune microenvironment (TIME) that promotes resistance to immunotherapy. A preclinical model system that facilitates studies of the TIME and its impact on the responsiveness of human PDAC to immunotherapies remains an unmet need. We report a novel mouse model, which develops metastatic human PDAC that becomes infiltrated by human immune cells recapitulating the TIME of human PDAC. The model may serve as a versatile platform to study the nature of human PDAC TIME and its response to various treatments.

cancer biology↗

Tumor-resident regulatory T cells in pancreatic cancer express the αvβ5 integrin as a targetable activation marker

Pancreatic ductal adenocarcinoma (PDAC) has abundant immunosuppressive regulatory T cells (Tregs), which contribute to a microenvironment resistant to immunotherapy. Here, we report that Tregs in the PDAC tissue, but not those in the spleen, express the v{beta}5 integrin in addition to neuropilin-1 (NRP-1), which makes them susceptible to the iRGD tumor-penetrating peptide, which targets cells positive for v integrin- and NRP-1. As a result, long-term treatment of PDAC mice with iRGD leads to tumor-specific depletion of Tregs and improved efficacy of immune checkpoint blockade. v{beta}5 integrin+ Tregs are induced from both naive CD4+ T cells and natural Tregs upon T cell receptor stimulation, and represent a highly immunosuppressive subpopulation of CCR8+ Tregs. This study identifies the v{beta}5 integrin as a marker for activated tumor-resident Tregs, which can be targeted to achieve tumor-specific Treg depletion and thereby augment anti-tumor immunity for PDAC therapy.

cancer biology↗

Glutamine mimicry suppresses tumor progression through asparagine metabolism in pancreatic ductal adenocarcinoma

In pancreatic ductal adenocarcinoma (PDAC), glutamine is a critical nutrient that drives a wide array of metabolic and biosynthetic processes that support tumor growth. Despite this established dependency, the targeting of specific enzymes involved in glutamine metabolism is yet to yield any clinical benefit. Here, we have examined the therapeutic potential of 6-diazo-5-oxo-L-norleucine (DON), a glutamine antagonist that broadly inhibits glutamine metabolism. We found that DON treatment significantly blocks PDAC tumor growth and attenuates metastasis. Interestingly, we link the effectiveness of DON in PDAC to asparagine (Asn) metabolism. By inhibiting asparagine synthetase (ASNS), DON significantly reduces intracellular Asn production and Asn supplementation rescues the anti-proliferative effects of DON. We discern that PDAC cells upregulate expression of ASNS as a metabolic adaptation and that modulating ASNS levels can impact DON efficacy. Strikingly, in patient-derived organoids, DON responsiveness is inversely correlated with ASNS expression, a feature that is not observed for other metabolic enzymes targeted by DON. We find that treatment with L-asparaginase (ASNase), an enzyme that catabolizes free Asn, synergizes with DON to impact the viability of PDAC cells. Finally, we identify that a combination therapy of DON and ASNase has a significant impact on metastasis. These results shed light on the mechanisms that drive the effects of glutamine mimicry and point to the utility of co-targeting adaptive responses to control PDAC progression.

cancer biology↗

Integrated Molecular Characterization of Intraductal Papillary Mucinous Neoplasms: An NCI Cancer Moonshot Precancer Atlas Pilot Project

Intraductal papillary mucinous neoplasms (IPMNs) are cystic precursor lesions to pancreatic ductal adenocarcinoma (PDAC). IPMNs undergo multistep progression from low grade (LG) to high grade (HG) dysplasia, culminating in invasive neoplasia. While patterns of IPMN progression have been analyzed using multi-region sequencing for somatic mutations, there is no integrated assessment of molecular events, including copy number alterations (CNAs) and transcriptomics changes, that accompany IPMN progression. We performed laser capture microdissection on surgically resected IPMNs of varying grades of histological dysplasia obtained from 24 patients (total of 74 independent histological lesions), followed by whole exome and whole transcriptome sequencing. Overall, HG IPMNs displayed a significantly greater aneuploidy score than LG lesions, with chromosome 1q amplification, in particular, being associated with HG progression and with cases that harbored cooccurring PDAC. Furthermore, the combined assessment of single nucleotide variants (SNVs) and CNAs identified both linear and branched evolutionary trajectories, underscoring the heterogeneity in the progression of LG lesions to HG and PDAC. At the transcriptome level, upregulation of MYC-regulated targets and downregulation of transcripts associated with the MHC class I antigen presentation machinery was a common feature of progression to HG. Taken together, this work emphasizes the role of 1q copy number amplification as a putative biomarker of high-risk IPMNs, underscores the importance of immune evasion even in non-invasive precursor lesions, and supports a previously underappreciated role of CNA-driven branching evolution as an avenue for IPMN progression. Our study provides important molecular context for risk stratification and cancer interception opportunities in IPMNs. SignificanceIntegrated molecular analysis of genomic and transcriptomic alterations in the multistep progression of intraductal papillary mucinous neoplasms (IPMNs), which are bona fide precursors of pancreatic cancer, identifies features associated with progression of low-risk lesions to high-risk lesions and cancer, which might enable patient stratification and cancer interception strategies.

cancer biology↗

Collagen remodeling dictates pancreatic cancer bioenergetics and outcome through DDR1 activation or degradation

Pancreatic ductal adenocarcinoma (PDAC) is a highly desmoplastic, aggressive cancer that frequently progresses by liver metastasis1. Cancer-associated fibroblasts (CAF), extracellular matrix (ECM), and type I collagen (Col I) support2-5 or restrain PDAC progression and may impede blood supply and nutrient availability6-8. The dichotomous role of the stroma in PDAC, and the mechanisms through which it influences patient survival and enables desmoplastic cancers escape nutrient limitation remain poorly understood. Here we show that matrix metalloprotease (MMP)-cleaved or intact Col I (cCol I and iCol I, respectively) exert opposing effects on PDAC bioenergetics, macropinocytosis (MP), tumor growth and liver metastasis. While cCol I activates DDR1 (discoidin domain receptor-1)-NF-{kappa}B-p62-NRF2 signaling to promote PDAC growth, iCol I triggers DDR1 degradation and restrains PDAC growth. Patients whose tumors are enriched in iCol I and low in DDR1 and NRF2 have improved median survival compared to those enriched in cCol I, DDR1 and NRF2. Inhibition of DDR1-stimulated NF-{kappa}B or mitochondrial biogenesis blocked tumorigenesis in wildtype mice but not in mice expressing MMP-resistant Col I. In summary, the diverse effects of tumor stroma on PDAC growth, metastasis, and patient survival are mediated through the Col I-DDR1-NF-{kappa}B-NRF2-mitochondrial biogenesis pathway, presenting multiple new opportunities for PDAC therapy.

cancer biology↗

Detection and quantification of GPCR mRNA: An assessment and implications of data from high-content methods

G protein-coupled receptors (GPCRs) are the largest family of membrane receptors and targets for approved drugs. Analysis of GPCR expression is thus important for drug discovery and typically involves mRNA-based methods. We compared transcriptomic cDNA [Affymetrix] microarrays, RNA-seq and qPCR-based TaqMan arrays for their ability to detect and quantify expression of endoGPCRs (non-chemosensory GPCRs with endogenous agonists). In human pancreatic cancer-associated fibroblasts, RNA-seq and TaqMan arrays yielded closely correlated values for GPCR number (~100) and expression levels, as validated by independent qPCR. By contrast, the microarrays failed to identify ~30 such GPCRs and generated data poorly correlated with results from those methods. RNA-seq and TaqMan arrays also yielded comparable results for GPCRs in human cardiac fibroblasts, pancreatic stellate cells, cancer cell lines and pulmonary arterial smooth muscle cells. The magnitude of mRNA expression for several Gq/11-coupled GPCRs predicted cytosolic calcium increase and cell migration by cognate agonists. RNA-seq also revealed splice variants for endoGPCRs. Thus, RNA-seq and qPCR-based arrays are better suited than microarrays for assessing GPCR expression and can yield results predictive of functional responses--findings that have implications for GPCR biology and drug discovery.\n\nAbstract Graphic\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=168 SRC=\"FIGDIR/small/734863v1_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (21K):\norg.highwire.dtl.DTLVardef@1a47e41org.highwire.dtl.DTLVardef@5ce56corg.highwire.dtl.DTLVardef@da5330org.highwire.dtl.DTLVardef@18b8215_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗