IDO1 inhibition potentiates vaccine-induced immunity against pancreatic adenocarcinoma

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Abstract

Pancreatic ductal adenocarcinoma (PDAC) represents an immune quiescent tumor that is resistant to immune checkpoint inhibitors. Previously, our group has shown that a GM-CSF secreting allogenic pancreatic tumor cell vaccine (GVAX), may prime the tumor microenvironment by inducing intratumoral T-cell infiltration. Here, we show that untreated PDACs express minimal indoleamine-2, 3-dioxygenase (IDO1); however, GVAX therapy induced IDO1 expression on tumor epithelia as well as vaccine-induced tertiary lymphoid aggregates. IDO1 expression plays a role in regulating the polarization of Th1, Th17, and possibly T-regulatory cells in PDAC tumors. IDO1 inhibitor enhanced anti-tumor efficacy of GVAX in a murine model of PDACs. The combination of vaccine and IDO1 inhibitor enhanced intratumoral T-cell infiltration and function, but adding anti-PD-L1 antibody to the combination did not offer further synergy and in fact may have a negative interaction decreasing the number of intratumoral effector T-cells. Additionally, IDO1 inhibitor in the presence of vaccine therapy, did not significantly modulate intratumoral myeloid derived suppressor cells quantitatively, but diminished their suppressive effect on CD8+ proliferation. Our study thus supports the combination of IDO1 inhibitor and vaccine therapy, however, does not support the combination of IDO1 inhibitor and anti-PD-1/PD-L1 antibody for T cell-inflamed tumors such as PDACs treated with vaccine therapy.

Authors

Alex B. Blair, Jennifer Kleponis, Dwayne L. Thomas II, Stephen T. Muth, Adrian G. Murphy, Victoria Kim, Lei Zheng

Spatially distinct tumor immune microenvironments stratify triple-negative breast cancers

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Abstract

Understanding the tumor immune microenvironment (TIME) promises to be key for optimal cancer therapy, especially in triple-negative breast cancer (TNBC). Integrating spatial resolution of immune cells with laser capture microdissection gene expression profiles, we defined distinct TIME stratification in TNBC with implications for current therapies, including immune checkpoint blockade. TNBCs with an immunoreactive microenvironment exhibited tumoral infiltration of granzyme B+ CD8+ T cells, a type I interferon signature, elevated expression of multiple immune inhibitory molecules, including IDO, PD-L1, and good outcome. An “immune-cold” microenvironment with absence of tumoral CD8+ T cells was defined by elevated expression of the immunosuppressive marker B7-H4, signatures of fibrotic stroma and poor outcome. A distinct poor outcome immunomodulatory microenvironment, hitherto poorly characterized, exhibited stromal restriction of CD8+ T cells, stromal expression of PD-L1 and enrichment for signatures of cholesterol biosynthesis. Metasignatures defining these TIME subtypes stratified TNBC, predicting outcome and identifying potential therapeutic targets for TNBC.

Authors

Tina Gruosso, Mathieu Gigoux, Venkata Satya Kumar Manem, Nicholas Bertos, Dongmei Zuo, Irina Perlitch, Sadiq Mehdi Ismail Saleh, Hong Zhao, Margarita Souleimanova, Radia Marie Johnson, Anne Monette, Valentina Munoz Ramos, Michael Trevor Hallett, John Stagg, Réjean Lapointe, Atilla Omeroglu, Sarkis Meterissian, Laurence Buisseret, Gert Van den Eynden, Roberto Salgado, Marie-Christine Guiot, Benjamin Haibe-Kains, Morag Park

Targeting compensatory MEK/ERK activation increases JAK inhibitor efficacy in myeloproliferative neoplasms

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Abstract

Constitutive JAK2 signaling is central to myeloproliferative neoplasm (MPN) pathogenesis and results in activation of STAT, PI3K/AKT and MEK/ERK signaling. However, the therapeutic efficacy of current JAK2 inhibitors is limited. We investigated the role of MEK/ERK signaling in MPN cell survival in the setting of JAK kinase inhibition. Type I and II JAK2 inhibition suppressed MEK/ERK activation in MPN cell lines in vitro, but not in Jak2V617F and MPLW515L mouse models in vivo. JAK2 inhibition ex vivo inhibited MEK/ERK signaling suggesting cell extrinsic factors maintain ERK activation in vivo. We identified PDGFRα as an activated kinase that remains activated upon JAK2 inhibition in vivo, and PDGF-AA/PDGF-BB production persisted in the setting of JAK kinase inhibition. PDGF-BB maintained ERK activation in presence of ruxolitinib consistent with its function as a ligand-induced bypass for ERK activation. Combined JAK/MEK inhibition suppressed MEK/ERK activation in Jak2V617F and MPLW515L mice with increased efficacy and reversal of fibrosis to an extent not seen with JAK inhibitors. This demonstrates that compensatory ERK activation limits the efficacy of JAK2 inhibition and dual JAK/MEK inhibition provides an opportunity for improved therapeutic efficacy in MPNs and in other malignancies driven by aberrant JAK-STAT signaling.

Authors

Simona Stivala, Tamara Codilupi, Sime Brkic, Anne Baerenwaldt, Nilabh Ghosh, Hui Hao-Shen, Stephan Dirnhofer, Matthias S. Dettmer, Cedric Simillion, Beat A. Kaufmann, Sophia Chiu, Matthew D. Keller, Maria Kleppe, Morgane Hilpert, Andreas S. Buser, Jakob R. Passweg, Thomas Radimerski, Radek C. Skoda, Ross L. Levine, Sara C. Meyer

uPAR isoform 2 forms a dimer and induces severe kidney disease in mice

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Abstract

Soluble urokinase plasminogen activator receptor (suPAR) is an immune-derived circulating signaling molecule that has been implicated in chronic kidney disease such as focal segmental glomerulosclerosis (FSGS). Typically, native uPAR (isoform 1) translates to a three-domain protein capable of binding and activating integrins, yet the function of additional isoforms generated by alternative splicing is unknown. Here, we characterized mouse uPAR isoform 2 (msuPAR2), encoding domain I and nearly one-half of domain II, as a dimer in solution, as revealed by 3D electron microscopy structural analysis. In vivo, msuPAR2 transgenic mice exhibited signs of severe renal disease characteristic of FSGS with proteinuria, loss of kidney function and glomerulosclerosis. Sequencing of the glomerular RNAs from msuPAR2-Tg mice revealed differentially expressed gene signature that includes upregulation of the suPAR receptor Itgb3, encoding β3 integrin. Crossing msuPAR2-transgenic mice with three different integrin β3 deficiency models rescued msuPAR2-mediated kidney function. Further analyses indicated a central role for β3 integrin and c-Src in msuPAR2 signaling and in human FSGS kidney biopsies. Administration of Src inhibitors reduced proteinuria in msuPAR2-transgenic mice. In conclusion, mouse uPAR isoform 2 may play an important role in certain forms of scarring kidney disease.

Authors

Changli Wei, Jing Li, Brian D. Adair, Ke Zhu, Jian Cai, Michael Merchant, Beata Samelko, Zhongji Liao, Kwi Hye Koh, Nicholas J. Tardi, Ranadheer R. Dande, Shuangxin Liu, Jianchao Ma, Salvatore DiBartolo, Stefan Hägele, Vasil Peev, Salim S. Hayek, David J. Cimbaluk, Melissa Tracy, Jon B. Klein, Sanja Sever, Sanford J. Shattil, M. Amin Arnaout, Jochen Reiser

Follicular lymphoma-associated mutations in vacuolar ATPase ATP6V1B2 activate autophagic flux and MTOR

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Abstract

The discovery of recurrent mutations in subunits of the vacuolar-type H+-translocating ATPase (v-ATPase) in follicular lymphoma (FL) highlights a role for the amino acid- and energy-sensing pathway to MTOR in the pathogenesis of this disease. Here, through the use of complementary experimental approaches involving mammalian cells and Saccharomyces cerevisiae, we have demonstrated that mutations in the v-ATPase subunit ATP6V1B2/Vma2 activate autophagic flux and maintain MTOR/Tor in an active state. Engineered lymphoma cell lines and primary follicular lymphoma B cells (FL B cells) carrying mutated ATP6V1B2 demonstrated a remarkable ability to survive low leucine concentrations. The treatment of primary FL B cells with inhibitors of autophagy uncovered an addiction for survival for FL B cells harboring ATP6V1B2 mutants. These data support mutational activation of autophagic flux by recurrent hotspot mutations in ATP6V1B2 as an adaptive mechanism in FL pathogenesis and as a new possible therapeutically targetable pathway.

Authors

Fangyang Wang, Damián Gatica, Zhang Xiao Ying, Luke F. Peterson, Peter K. Kim, Denzil Bernard, Kamlai Saiya-Cork, Shaomeng Wang, Mark S. Kaminski, Alfred E. Chang, Tycel Phillips, Daniel J. Klionsky, Sami N. Malek

Circulating heparan sulfate fragments mediate septic cognitive dysfunction

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Abstract

Septic patients frequently develop cognitive impairment that persists beyond hospital discharge. The impact of sepsis on electrophysiological and molecular determinants of learning is underexplored. We observed that mouse survivors of sepsis or endotoxemia experienced loss of hippocampal long-term potentiation (LTP), a brain-derived neurotrophic factor (BDNF)-mediated process responsible for spatial memory formation. Memory impairment occurred despite preserved hippocampal BDNF content and could be reversed by stimulation of BDNF signaling, suggesting the presence of a local BDNF inhibitor. Sepsis is associated with degradation of the endothelial glycocalyx, releasing heparan sulfate fragments (of sufficient size and sulfation to bind BDNF) into the circulation. Heparan sulfate fragments penetrated the hippocampal blood-brain barrier during sepsis and inhibited BDNF-mediated LTP. Glycoarray approaches demonstrated that heparan sulfate’s avidity for BDNF increased with sulfation at the 2-O-position of iduronic acid and N-position of glucosamine. Circulating heparan sulfate in endotoxemic mice and septic humans was enriched in 2-O- and N-sulfated disaccharides; furthermore, the presence of these sulfation patterns in the plasma of septic patients at intensive care unit (ICU) admission predicted persistent cognitive impairment 14 days after ICU discharge or at hospital discharge. Our findings indicate that circulating 2-O- and N-sulfated heparan sulfate fragments contribute to septic cognitive impairment.

Authors

Joseph A. Hippensteel, Brian J. Anderson, James E. Orfila, Sarah A. McMurtry, Robert M. Dietz, Guowei Su, Joshay A. Ford, Kaori Oshima, Yimu Yang, Fuming Zhang, Xiaorui Han, Yanlei Yu, Jian Liu, Robert J. Linhardt, Nuala J. Meyer, Paco S. Herson, Eric P. Schmidt

RABL6A inhibits tumor-suppressive PP2A/AKT signaling to drive pancreatic neuroendocrine tumor growth

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Abstract

Hyperactivated AKT/mTOR signaling is a hallmark of pancreatic neuroendocrine tumors (PNETs). Drugs targeting this pathway are used clinically but tumor resistance invariably develops. A better understanding of factors regulating AKT/mTOR signaling and PNET pathogenesis is needed to improve current therapies. We discovered that RABL6A, a new oncogenic driver of PNET proliferation, is required for AKT activity. Silencing RABL6A caused PNET cell cycle arrest that coincided with selective loss of AKT-S473 (not T308) phosphorylation and AKT/mTOR inactivation. Restoration of AKT phosphorylation rescued the G1 phase block triggered by RABL6A silencing. Mechanistically, loss of AKT-S473 phosphorylation in RABL6A depleted cells resulted from increased protein phosphatase 2A (PP2A) activity. Inhibition of PP2A restored phosphorylation of AKT-S473 in RABL6A depleted cells whereas PP2A reactivation using a specific small molecule activator of PP2A (SMAP) abolished that phosphorylation. Moreover, SMAP treatment effectively killed PNET cells in a RABL6A-dependent manner and suppressed PNET growth in vivo. This work identifies RABL6A as a new inhibitor of the PP2A tumor suppressor and essential activator of AKT in PNET cells. Our findings offer what we believe is a novel strategy of PP2A reactivation for treatment of PNETs as well as other human cancers driven by RABL6A overexpression and PP2A inactivation.

Authors

Shaikamjad Umesalma, Courtney A. Kaemmer, Jordan L. Kohlmeyer, Blake L. Letney, Angela M. Schab, Jacqueline A. Reilly, Ryan M. Sheehy, Jussara Hagen, Nitija Tiwari, Fenghuang Zhan, Mariah R. Leidinger, Thomas M. O'Dorisio, Joseph S. Dillon, Ronald A. Merrill, David K. Meyerholz, Abbey L. Perl, Bart J. Brown, Terry A. Braun, Aaron T. Scott, Timothy Ginader, Agshin F. Taghiyev, Gideon K. Zamba, James R. Howe, Stefan Strack, Andrew M. Bellizzi, Goutham Narla, Benjamin W. Darbro, Frederick W. Quelle, Dawn E. Quelle

Ascorbic acid–induced TET activation mitigates adverse hydroxymethylcystosine loss in renal cell carcinoma

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Abstract

Although ccRCC has been shown to have widespread aberrant cytosine methylation and loss of hydroxymethylation (5hmC), the prognostic impact and therapeutic targeting of this epigenetic aberrancy has not been fully explored. Analysis of 576 primary ccRCC samples demonstrated that loss of 5hmC was significantly associated with aggressive clinicopathologic features and was an independent adverse prognostic factor. Loss of 5hmC also predicted reduced progression free survival after resection of non-metastatic disease. The loss of 5hmC in ccRCC was not due to mutational or transcriptional inactivation of TET enzymes, but by their functional inactivation by l-2-hydroxyglutarate (L2HG) that was overexpressed due to the deletion and under-expression of l-2-hydroxyglutarate dehydrogenase (L2HGDH). Ascorbic acid (AA) reduced methylation and restored genome wide 5hmC levels via TET activation. Fluorescence quenching of the recombinant TET-2 protein was unaffected by L2HG in the presence of AA. Pharmacologic AA treatment led to reduced growth of ccRCC in vitro and reduced tumor growth in vivo, with increased intratumoral 5hmC. These data demonstrate that reduced 5hmC is associated with reduced survival in ccRCC and provide a preclinical rationale for exploring the therapeutic potential of high dose AA in ccRCC.

Authors

Niraj Shenoy, Tushar D. Bhagat, John C. Cheville, Christine Lohse, Sanchari Bhattacharyya, Alexander Tischer, Venkata Machha, Shanisha Gordon-Mitchell, Gaurav S. Choudhary, Li-Fan Wong, LouAnn Gross, Emily Ressegue, Bradley C. Leibovich, Stephen A. Boorjian, Ulrich Steidl, Xiaosheng Wu, Kith Pradhan, Benjamin Gartrell, Beamon Agarwal, Lance Pagliaro, Masako Suzuki, John M. Greally, Dinesh Rakheja, R. Houston Thompson, Katalin Susztak, Thomas Witzig, Yiyu Zou, Amit Verma

T cells genetically engineered to overcome death signaling enhance adoptive cancer immunotherapy

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Abstract

Across clinical trials, T cell expansion and persistence following adoptive cell transfer (ACT) have correlated with superior patient outcomes. Herein, we undertook a pan-cancer analysis to identify actionable ligand/receptor pairs capable of compromising T cell durability following ACT. We discovered that FASLG, the gene encoding the apoptosis-inducing ligand FasL, is overexpressed within the majority of human tumor microenvironments (TMEs). Further, we uncovered that Fas, the receptor for FasL, is highly expressed on patient-derived T cells used for clinical ACT. We hypothesized that a cognate Fas-FasL interaction within the TME might limit both T cell persistence and anti-tumor efficacy. We discovered that genetic engineering of Fas variants impaired in the ability to bind FADD functioned as dominant negative receptors (DNRs), preventing FasL-induced apoptosis in Fas-competent T cells. T cells co-engineered with a Fas DNR and either a T cell receptor or chimeric antigen receptor exhibited enhanced persistence following ACT, resulting in superior anti-tumor efficacy against established solid and hematologic cancers. Despite increased longevity, Fas DNR-engineered T cells did not undergo aberrant expansion or mediate autoimmunity. Thus, T cell-intrinsic disruption of Fas signaling through genetic engineering represents a potentially universal strategy to enhance ACT efficacy across a broad range of human malignancies.

Authors

Tori N. Yamamoto, Ping-Hsien Lee, Suman K. Vodnala, Devikala Gurusamy, Rigel J. Kishton, Zhiya Yu, Arash Eidizadeh, Robert Eil, Jessica Fioravanti, Luca Gattinoni, James N. Kochenderfer, Terry J. Fry, Bulent Arman Aksoy, Jeffrey Hammerbacher, Anthony C. Cruz, Richard M. Siegel, Nicholas P. Restifo, Christopher A. Klebanoff

Abolition of aberrant neurogenesis ameliorates cognitive impairment after stroke in mice

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Abstract

Post-stroke cognitive impairment is considered one of the main complications during the chronic phase of ischemic stroke. In the adult brain, the hippocampus regulates both encoding and retrieval of new information through adult neurogenesis. Nevertheless, the lack of predictive models and studies based on the forgetting processes hinder the understanding of memory alterations after stroke. Our aim was to explore whether post-stroke neurogenesis participates in the development of long-term memory impairment. Here we show a hippocampal neurogenesis burst that persisted one month after stroke and that correlated with an impaired contextual and spatial memory performance. Furthermore, we demonstrate that the enhancement of hippocampal neurogenesis after stroke by physical activity or memantine treatment weakened existing memories. More importantly, stroke-induced newborn neurons promoted an aberrant hippocampal circuitry remodelling with differential features at ipsi- and contralesional levels. Strikingly, inhibition of stroke-induced hippocampal neurogenesis by temozolomide treatment or using a genetic approach (Nestin-CreERT2/NSE-DTA mice) impeded the forgetting of old memories. These results suggest that hippocampal neurogenesis modulation could be considered as a potential approach for post-stroke cognitive impairment.

Authors

María Isabel Cuartero, Juan de la Parra, Alberto Pérez-Ruiz, Isabel Bravo-Ferrer, Violeta Durán-Laforet, Alicia García-Culebras, Juan Manuel García-Segura, Jagroop Dhaliwal, Paul W. Frankland, Ignacio Lizasoain, María Àngeles Moro