About

Crystal S. Conn, PhD, is an Assistant Professor of Radiation Oncology at the Perelman School of Medicine at the University of Pennsylvania. Her research expertise encompasses cancer biology, adaptive stress responses, mRNA translation, RNA modifications, drug targeting, protein homeostasis, ribosome profiling, and proteomics, utilizing both in vivo and ex vivo models. Dr. Conn's research program focuses on understanding the signaling pathways activated in cancer cells that enable their adaptation to various stresses during cellular transformation and disease progression. She investigates how aggressive cancer cells rewire their translational machinery to select specific mRNAs for protein expression and identifies unique isoforms created through non-conventional initiation, exploring their functions and relevance to disease detection and therapeutic targeting. Her work aims to uncover phenotypic vulnerabilities in malignant cells that can be exploited for improved treatments and prevention strategies.

Research topics

• Biology
• Cell biology
• Cancer research
• Chemistry
• Internal medicine

Selected publications

• SPTBN2 promotes an immunosuppressive tumor microenvironment and cross-resistance to anti-cancer therapies

  bioRxiv (Cold Spring Harbor Laboratory) · 2026-04-01

  articleOpen access

  Immunosuppressive tumor microenvironment (TME) inactivates CD8+ cytotoxic lymphocytes (CTLs). Here, we identify SPTBN2 spectrin as a key immunosuppressive regulator induced in CTLs in response to nutritional deficit. In human pancreatic and colorectal cancers, SPTBN2 expression negatively correlated with CTL infiltration and patients' survival. In TME of mouse pancreatic and colorectal adenocarcinomas, SPTBN2 inactivated intratumoral CTLs, stimulated tumor growth and conferred cross-resistance to anti-cancer therapies. SPTBN2 knockout protected CAR T-cells from trogocytosis and increased their memory state. SPTBN2 maintained levels of cell surface proteins such as BTLA that undermine CAR T-cell cytotoxicity and promote exhaustion. Re-expression of BTLA largely reversed phenotypes in SPTBN2-deficient CAR T-cells. In manufactured CAR T cells, SPTBN2 was associated with their clinical failure in pediatric patients with leukemia. Accordingly, ablation of SPTBN2 in CAR T-cells increased their cytotoxicity, in vivo persistence and therapeutic effects indicating that SPTBN2 can be targeted to increase the efficacy of anti-cancer therapies.

  PublisherOA PDFDOI

• Environmental Amino Acid Sensing Regulates the Rate of ASC Translation and NLRP3 Inflammasome Assembly

  bioRxiv (Cold Spring Harbor Laboratory) · 2026-01-20 · 1 citations

  articleOpen access

  ABSTRACT The NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome is a multiprotein signaling complex that triggers pyroptotic cell death and interleukin (IL)-1 family cytokine release during infection and cell injury. Its assembly is driven by the adaptor protein, apoptosis-associated speck-like protein containing a CARD (ASC), whose filamentation forms a supramolecular speck upon NLRP3 activation to amplify inflammasome signaling. While the NLRP3 inflammasome is well appreciated as a sensor of environmental danger and damage, little is known about how homeostatic environmental factors like dietary metabolites regulate its activity. Here, we find that environmental availability of the branched-chain amino acids (BCAAs), leucine, isoleucine, and valine, controls NLRP3 inflammasome assembly. While ASC is typically viewed as a constitutively expressed, unregulated inflammasome component, we find that Toll-like receptor 4 (TLR4) activation triggers localization of ASC mRNA to the perinuclear space. Moreover, our data demonstrate that ASC undergoes TLR4-driven translational bursting from polyribosomes during inflammasome priming. This translational engagement is dependent on BCAA availability and mechanistic target of rapamycin (mTOR) activity, which regulate the kinetics of inflammasome assembly. In contrast, the translation of NLRP3 and caspase-1 is largely insensitive to these inputs. Furthermore, we find that BCAAs regulate NLRP3 inflammasome activation in both mouse and human macrophages, in the context of bacterial infection, and during lipopolysaccharide (LPS)-induced sepsis in vivo . Altogether, this work unveils a novel inflammasome priming event governed by the amino acid environment. These findings further highlight how the activity of proteins maintained in equilibrium like ASC can be dynamically regulated through rapid changes in mRNA translation.

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• Metabolic and transcriptional plasticity supports CD8+ T cell resilience and anti-tumor immunity under nutrient stress

  Immunity · 2026-04-30

  article
  PublisherDOI

• Biosynthetic plasticity enables CD8+ T cell functional resilience under nutrient stress

  bioRxiv (Cold Spring Harbor Laboratory) · 2025-01-24 · 3 citations

  preprintOpen access

  Summary / Abstract To maintain lineage-specific functions, cells must acquire and allocate nutrients across diverse cellular processes, even in metabolically-dysregulated environments. The mechanisms allowing CD8+ T cells to maintain immune function in perturbed environments are poorly understood. We find that CD8+ T cells adapt to nutrient stresses over time, reconfiguring gene-regulatory and metabolic networks to license functional recovery. Under acute stress, T cells reorient translational programming, limiting nutrient demand while prioritizing stress-sensitive metabolic and transcriptional responses. Within these responses, the transcription factors ATF4 and CEBPG jointly establish an adaptive metabolic program, promoting amino acid synthesis and uptake while maintaining mitochondrial anaplerosis. Despite diminished energetic capacity under environmental stress, this program prevents failure of central carbon metabolism, mitigating stress amplification and cellular dysfunction to potentiate anti-tumor immunity. Altogether, we demonstrate that biosynthetic plasticity via translational and metabolic reprioritization confers functional resilience to immune cells in unfavorable environments, offering novel strategies to enhance immunotherapies.

  PublisherOA PDFDOI

• m6A Immunoprecipitation from Ribosome-Bound mRNA

  Methods in enzymology on CD-ROM/Methods in enzymology · 2025-01-01

  book-chapterSenior authorCorresponding
  PublisherDOI

• Branched-chain amino acid sensing anabolically licenses NLRP3 inflammasome assembly and IL-1 cytokine release 2168

  The Journal of Immunology · 2025-11-01

  articleOpen access

  Abstract Description The NLRP3 inflammasome is a multiprotein complex that triggers pyroptosis during infection and cell injury. Its assembly is mediated by the adaptor protein ASC, whose aggregation amplifies proximity-induced caspase-1 autoproteolysis. Although the molecular events that promote inflammasome triggering are extensively documented, their regulation by metabolite sensing pathways remains poorly understood. Here, using a novel metabolic screen entailing macrophage starvation of individual and defined groups of amino acids, we identify sensing of the essential branched-chain amino acids (BCAAs) leucine, isoleucine, and valine as a critical signal for anabolically licensing NLRP3 inflammasome activation. Provision of the BCAAs during TLR4-driven inflammasome priming is required for subsequent NLRP3-triggered ASC speck assembly, caspase-1 cleavage, membrane permeability, and IL-1 release. Mechanistically, polysome profiling revealed that TLR4 activation promotes IL-1 and ASC translational bursting from polyribosomes, an effect that is thwarted in BCAA-starved macrophages, which are otherwise only modestly impaired in their priming of NLRP3. In vivo, dietary restriction of the BCAAs protected mice from mortality in an inflammasome-driven model of endotoxic shock. We therefore propose that BCAA sensing during TLR4 activation is translationally required to both prime IL-1 and locally concentrate ASC expression for enabling oligomerization of the inflammasome speck upon NLRP3 activation. Funding Sources Supported by American Heart Association Postdoctoral Fellowship and NIH/NIAID R01AI118861 Topic Categories Innate Immune Responses and Host Defense: Cellular Mechanisms (INC)

  PublisherOA PDFDOI

• ROR2 drives right ventricular heart failure via disruption of proteostasis

  bioRxiv (Cold Spring Harbor Laboratory) · 2025-02-02 · 1 citations

  preprintOpen access

  Background: No therapies exist to reverse right ventricular failure (RVF), and the molecular mechanisms that drive RVF remain poorly studied. We recently reported that the developmentally restricted noncanonical WNT receptor ROR2 is upregulated in human RVF in proportion to severity of disease. Here we test mechanistic role of ROR2 in RVF pathogenesis. Methods: ROR2 was overexpressed or knocked down in neonatal rat ventricular myocytes (NRVMs). ROR2-modified NRVMs were characterized using confocal microscopy, RNAseq, proteomics, proteostatic functional assays, and contractile properties with pacing. The impact of cardiac ROR2 expression was evaluated in mice by AAV9-mediated overexpression and by AAV9-mediated delivery of shRNA to knockdown ROR2 in a pulmonary artery banded pressure overload RVF model. ROR2-modified mice were evaluated by echocardiography, RV protein synthetic rates and proteasome activity. Results: In NRVMs, we find that ROR2 profoundly dysregulates the coordination between protein translation and folding. This imbalance leads to excess protein clearance by the ubiquitin proteasome system (UPS) with dramatic impacts on sarcomere and cytoskeletal structure and function. In mice, forced cardiac ROR2 expression is sufficient to disrupt proteostasis and drive RVF, while conversely ROR2 knockdown partially rescues proteostasis and cardiac function in a pressure overload model of RVF. Conclusions: In sum, ROR2 is a key driver of RVF pathogenesis through proteostatic disruption and, thus, provides a promising target to treat RVF.

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• Abstract Tu051: ROR2 Drives Right Ventricular Failure Via Proteostatic Imbalances

  Circulation Research · 2024-08-02

  article

  Background: No therapies exist to treat right ventricular failure (RVF), in part because RVF molecular drivers have been incompletely studied. We recently identified that the developmentally restricted noncanonical WNT receptor ROR2 is re-expressed in a severity-dependent manner in human RVF. Here we test in mice if, and how, the re-expression of Ror2 causes RVF. Methods/Results: We find in neonatal rat ventricular myocytes (NRVMs) that Ror2 overexpression (Ror2 OE ) both activates protein translation and reduces Hspa1a/b mRNA and Hsp70 protein, resulting in increased protein turnover, fragmented sarcomeres, intercalated disc disruption, reduced cell major axis, impairment of contractile and relaxation kinetics, and ectopy. Ror2 knockdown (Ror2 KD ) results in opposing phenotypes. Hsp70 overexpression or proteasome inhibition rescues many of the Ror2 OE phenotypes, demonstrating their causal involvement. NRVM proteomic analysis indicates that Ror2 OE activates an ERK/p90RSK/Eef2 pathway that is known to regulate translation extension. In vivo, cardiac Ror2 OE in mice causes RV dilation and dysfunction, intercalated disc disruption, reduced Hspa1b (encoding for Hsp70), proteasome activation, and reduced cardiomyocyte ubiquitin staining. The mouse pulmonary artery banding (PAB) model of RVF reveals similar Ror2 induction and proteasome activation. Ror2 KD by AAV9 in PAB reduces RV dilation and improves RV systolic and diastolic function. Finally, in cardiac samples from human RVF, we find evidence for a similar ROR2-responsive proteostatic imbalance with increased proteasome activity and ubiquitin as well as markers of increased ERK and p90RSK. Conclusions: ROR2 is induced in human and mouse RVF, and mechanistic studies in NRVMs and mice show that the induction of ROR2 causes RVF by disrupting the proteostatic balance of translation, folding, and turnover. Knockdown or suppression of ROR2 may serve as a novel RVF therapeutic target.

  PublisherDOI

• Targeting stress induction of GRP78 by cardiac glycoside oleandrin dually suppresses cancer and COVID-19

  Cell & Bioscience · 2024-09-06 · 10 citations

  articleOpen access

  Abstract Background Despite recent therapeutic advances, combating cancer resistance remains a formidable challenge. The 78-kilodalton glucose-regulated protein (GRP78), a key stress-inducible endoplasmic reticulum (ER) chaperone, plays a crucial role in both cancer cell survival and stress adaptation. GRP78 is also upregulated during SARS-CoV-2 infection and acts as a critical host factor. Recently, we discovered cardiac glycosides (CGs) as novel suppressors of GRP78 stress induction through a high-throughput screen of clinically relevant compound libraries. This study aims to test the possibility that agents capable of blocking stress induction of GRP78 could dually suppress cancer and COVID-19. Results Here we report that oleandrin (OLN), is the most potent among the CGs in inhibiting acute stress induction of total GRP78, which also results in reduced cell surface and nuclear forms of GRP78 in stressed cells. The inhibition of stress induction of GRP78 is at the post-transcriptional level, independent of protein degradation and autophagy and may involve translational control as OLN blocks stress-induced loading of ribosomes onto GRP78 mRNAs. Moreover, the human Na + /K + -ATPase α3 isoform is critical for OLN suppression of GRP78 stress induction. OLN, in nanomolar range, enhances apoptosis, sensitizes colorectal cancer cells to chemotherapeutic agents, and reduces the viability of patient-derived colon cancer organoids. Likewise, OLN, suppresses GRP78 expression and impedes tumor growth in an orthotopic breast cancer xenograft model. Furthermore, OLN blocks infection by SARS-CoV-2 and its variants and enhances existing anti-viral therapies. Notably, GRP78 overexpression mitigates OLN-mediated cancer cell apoptotic onset and suppression of virus release. Conclusion Our findings validate GRP78 as a target of OLN anti-cancer and anti-viral activities. These proof-of-principle studies support further investigation of OLN as a readily accessible compound to dually combat cancer and COVID-19.

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• Supplemental Methods, Supplemental Figure 1-24 from Noninvasive Measurement of mTORC1 Signaling with <sup>89</sup>Zr-Transferrin

  2023-03-31

  preprintOpen access

  <p>Supplemental Methods, Supplementary Figure 1. A. Real time PCR data showing the suppression of PTEN mRNA levels by an anti PTEN shRNA in GBM and PCa cell lines. The suppression of PTEN mRNA was statistically significant (P < 0.05). B. Immunoblot data showing suppression of PTEN protein in the cell line cohort. Supplementary Figure 2. A. Real time PCR data showing the upregulation of PIK3CA wild type and mutant mRNA in HEK293 cells. Lysates were collected for analysis 48 hours after transfection. The upregulation was statistically significant (P < 0.05). SSupplementary Figure 3. A. Real time PCR data showing the upregulation of mTOR wild type and mutant mRNA in HEK293 cells. Lysates were collected for analysis 48 hours after transfection. The upregulation was statistically significant compared to mock (P < 0.05). Supplemental Figure 4. Right: In vitro uptake data showing that transient knockdown of TSC1 or TSC2 results in higher intracellular uptake of 125I-transferrin in NIH-3T3 cells. The cells were transfected for 48 hours prior to running the uptake assay for 1 hour. Left: In vitro uptake data showing that 125I-transferrin is internalized into TSC1-/- and TSC2-/- MEFs to a greater extent than the respective wild type subline. The uptake assay was conducted for 1 hour. The uptake was statistically significant compare to the respective parental line (P < 0.05). Supplemental Figure 5. Real time PCR data showing the knockdown of TSC1 or 2 mRNA by siRNA. Dharmacon smartPOOL siRNAs were transfected into NIH-3T3 cells for 48 hours prior to harvest. The gene knockdown was statistically significant (P < 0.01). Supplemental Figure 6. A photograph and PET images of wild type and PTEN null prostate tissues show higher uptake of the radiotracer in the PTEN null tissues. The contralateral lobes of the prostate are arranged with bilateral symmetry along a vertical axis cutting through the middle of the petri dish. Additional normal tissues from the urogenital tract are shown for comparison. Abbreviations: AP = anterior prostate, DP = dorsal prostate, VP = ventral prostate, LP = lateral prostate, B = bladder, SV = seminal vesicle, Ur = urethra. Supplemental Figure 7. A summary of the biodistribution data for all tissues in the Pb-cre PTENlox/lox mice. The statistics for the prostate lobes were described in the text. Supplementary Figure 8. Immunoblot data showing changes in phosphoprotein abundance in the PI3K/Akt/mTOR signaling axis, indicative of bioactivity for the respective kinase inhibitor in PTEN null GBM and PCa cell lines. Note no change in phosphoprotein levels for doxorubicin, as expected. Lysates were harvested 6 hours after the initiation of therapy. Supplementary Figure 9. A summary of the 125I-transferrin uptake data for all doses and treatment durations of BEZ235 in the PTEN null cell lines. The suppression of Tf uptake was statistically significant compared to vehicle treated cells (P < 0.05). Supplementary Figure 10. A summary of the 125I-transferrin uptake data for all doses and treatment durations of INK128 in the PTEN null cell lines. The suppression of Tf uptake was statistically significant compared to vehicle treated cells (P < 0.05). Supplementary Figure 11. A summary of the 125I-transferrin uptake data for all doses and treatment durations of RAD001 in the PTEN null cell lines. The suppression of Tf uptake was statistically significant compared to vehicle treated cells (P < 0.05). Supplementary Figure 12. A summary of the 125I-transferrin uptake data for all doses and treatment durations of doxorubicin in the PTEN null cell lines. Supplementary Figure 13. Immunoblot data showing changes in phosphor-S6 (Ser 240/44), indicative of bioactivity for the respective kinase inhibitor in T47D or HCT115 cells. Note no change in phosphoprotein levels for doxorubicin, as expected. Lysates were harvested 24 hours after the initiation of therapy. Supplementary Figure 14. A summary of the 125I-transferrin uptake data for all doses and treatment durations of BEZ235, INK128, RAD001 and doxorubicin in the T47D cells. The suppression of Tf uptake was statistically significant compared to vehicle treated cells (P < 0.05 for all treatments except doxorubicin). Supplementary Figure 15. A summary of the 125I-transferrin uptake data for all doses and treatment durations of BEZ235, INK128, RAD001 and doxorubicin in the HCT115 cells. The suppression of Tf uptake was statistically significant compared to vehicle treated cells (P < 0.05 for all treatments except doxorubicin). Supplementary Figure 16. Real time PCR data showing the efficacy of siRNA knockdown using the Dharmacon smartPOOL reagents. These data were collected 48 hours post transfection. The knockdown was statistically significant compared to cells treated with non-targeting (NT) siRNA (P < 0.01). Supplementary Figure 17. Pharmacological inhibition of mTORC1 activity suppresses TFRC transcription in vitro. (Left). Real time PCR data collected in vitro after 48 hours of treatment shows a substantial reduction in TFRC mRNA by treatment with targeted therapies, and no effect of doxorubicin, as expected, in U87MG, LNCaP-AR and PC3 cells. The doses of drugs were BEZ235 (100 nM), INK128 (100 nM), RAD001 (10 nM) and Doxorubicin (500 nM). (Right). An in vitro binding assay with 125I-DF1513 (a monoclonal antibody recognizing an extracellular epitope on human TFRC) shows that the abundance of cell surface TFRC is reduced by BEZ235 (100 nM), INK128 (100 nM), and RAD001 (10 nM) compared to vehicle. No effect was observed with Doxorubicin (500 nM). Cells were treated for 48 hours with drug, and incubated with 125I-DF1513 for 30 min at 4o C before isolating and counting the cell associated activity. In all cases, treatment with kinase inhibitors resulted in statistically significant decreases compared to vehicle and doxorubicin (P < 0.01). Supplementary Figure 18. Genetic inhibition of mTORC1 activity suppresses TFRC transcription in vitro. ( Left).Real time PCR data collected in vitro after 48 hours of transfection shows a substantial reduction in TFRC mRNA induced by siRNA to mTOR and RAPTOR, but not the mTORC2 component PRR5. Knockdown was confirmed with rtPCR. (Right) An in vitro binding assay with 125I-DF1513 shows that the abundance of cell surface TFRC is reduced by siRNAs (100 nmol) targeting mTOR and RPTOR compared to a nontargeting (NT) siRNA. No effect was observed with siRNA targeting PRR5, as expected. Cells were transfected for 48 hours, and incubated with 125I-DF1513 for 30 min at 4o C before isolating and counting the cell associated activity. In all cases, siRNA to mTOR or RPTOR resulted in statistically significant decrease in TFRC mRNA or protein compare to NT and siRNA against PRR5 (P < 0.01). Supplemental Figure 19. A summary of the biodistribution data for mice bearing subcutaneous U87 tumors, and treated with BEZ235, INK128, RAD001, or doxorubicin. The statistics for the tumor associated values were described in the text. Supplementary Figure 20. ROI analysis of the U87MG tumors in mice treated with vehicle or the indicated inhibitor. This data was derived from the same cohort used to generate the biodistribution data. The changes associated with the kinase inhibitors were statistically significant compare to vehicle and doxorubicin (P < 0.01). Supplementary Figure 21. A summary of the biodistribution data for mice bearing subcutaneous LNCaP tumors, and treated with BEZ235, INK128, RAD001, or doxorubicin. The statistics associated with the tumor values were described in the text. Supplementary Figure 22. A summary of the biodistribution data for mice bearing subcutaneous PC3 tumors, and treated with BEZ235, INK128, RAD001, or doxorubicin. The statistics associated with the tumor values were described in the text. Supplemental Figure 23. In vitro uptake data showing the impact of treatment dosing and changing exposure time in LNCaP-AR cells. The values on the X-axis refer to the amount of time LNCaP-AR was exposed to drug prior to 1 hour incubation with 125I-Tf. The cell surface and internalized activity was quantified, and normalized to vehicle treated cells. All treatments with the exception of ARN (1 �M) and ARN + RAD were statistically significant compared to vehicle (P < 0.01). Supplemental Figure 24. Biodistribution data from mouse tissues and tumors treated with vehicle, RAD001, ARN-509, or the combination for two days prior to injection with 89Zr-Tf. The biodistribution was collected 48 hours post injection of radiotracer. The statistics associated with the tumor values were described in the text.</p>

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Recent grants

• NIH Grant F32CA189696

  NIH · $18k · 2014

Frequent coauthors

• Davide Ruggero

  University of California, San Francisco

  31 shared

• J. T. Cunningham

  University of Cincinnati Medical Center

  11 shared

• Charles Truillet

  Commissariat à l'Énergie Atomique et aux Énergies Alternatives

  9 shared

• Jason S. Lewis

  Cornell University

  8 shared

• Michael J. Evans

  University of California, San Francisco

  8 shared

• Shu‐Bing Qian

  Cornell University

  7 shared

• Matthew F.L. Parker

  Stony Brook University

  6 shared

• Constantinos Koumenis

  University of Pennsylvania

  6 shared

Education

• Ph.D., Molecular Biology and Genetics

  Cornell University

  2013

• B.S., Biochemistry and Molecular Biology

  Penn State

  2007