Abstract
Metastatic colorectal cancer (CRC) is poorly immunogenic, with limited neoantigens that can be targeted by cancer vaccine. Previous approaches to upregulate neoantigen have had limited success. In this study, we investigated the role of a DNA methyltransferase inhibitor (DNMTi), 5-aza-2′-deoxycytidine (DAC), in inducing cancer testis antigen (CTA) expression and evaluated the antitumor efficacy of a combinatorial approach with an epigenetically regulated cancer vaccine EpiGVAX and DAC. A murine model of metastatic CRC treated with combination therapy with an irradiated whole-cell CRC vaccine (GVAX) and DAC was used to assess the antitumor efficacy. DAC significantly induced expression of CTAs in CRC, including a new CTA Tra-P1A with a known neoepitope, P1A. Epigenetically modified EpiGVAX with DAC improved survival outcomes of GVAX. Using the epigenetically regulated antigen Tra-P1A as an example, our study suggests that the improved efficacy of EpiGVAX with DAC may due in part to the enhanced antigen-specific antitumor immune responses. This study shows that epigenetic therapy with DNMTi can not only induce new CTA expression but may also sensitize tumor cells for immunotherapy. Neoantigen-based EpiGVAX combined with DAC can improve the antitumor efficacy of GVAX by inducing antigen-specific antitumor T cell responses to epigenetically regulated proteins.
Authors
Victoria M. Kim, Xingyi Pan, Kevin C. Soares, Nilofer S. Azad, Nita Ahuja, Christopher J. Gamper, Alex B. Blair, Stephen Muth, Ding Ding, Brian H. Ladle, Lei Zheng
Abstract
Doxorubicin (DOX), a chemotherapeutic agent, induces a cardiotoxicity referred to as doxorubicin-induced cardiomyopathy (DIC). This cardiotoxicity often limits chemotherapy for malignancies and is associated with poor prognosis. However, the molecular mechanism underlying this cardiotoxicity is yet to be fully elucidated. Here, we show that DOX downregulated glutathione peroxidase 4 (GPx4) and induced excessive lipid peroxidation through DOX-Fe2+ complex in mitochondria, leading to mitochondria-dependent ferroptosis; we also show that mitochondria-dependent ferroptosis is a major cause of DOX cardiotoxicity. In DIC mice, the left ventricular ejection fraction was significantly impaired, and fibrosis and TUNEL+ cells were induced at day 14. Additionally, GPx4, an endogenous regulator of ferroptosis, was downregulated, accompanied by the accumulation of lipid peroxides, especially in mitochondria. These cardiac impairments were ameliorated in GPx4 Tg mice and exacerbated in GPx4 heterodeletion mice. In cultured cardiomyocytes, GPx4 overexpression or iron chelation targeting Fe2+ in mitochondria prevented DOX-induced ferroptosis, demonstrating that DOX triggered ferroptosis in mitochondria. Furthermore, concomitant inhibition of ferroptosis and apoptosis with ferrostatin-1 and zVAD-FMK fully prevented DOX-induced cardiomyocyte death. Our findings suggest that mitochondria-dependent ferroptosis plays a key role in progression of DIC and that ferroptosis is the major form of regulated cell death in DOX cardiotoxicity.
Authors
Tomonori Tadokoro, Masataka Ikeda, Tomomi Ide, Hiroko Deguchi, Soichiro Ikeda, Kosuke Okabe, Akihito Ishikita, Shouji Matsushima, Tomoko Koumura, Ken-ichi Yamada, Hirotaka Imai, Hiroyuki Tsutsui
Abstract
Immune checkpoint blockade immunotherapy delivers promising clinical results in colorectal cancer (CRC). However, only a fraction of cancer patients develop durable responses. The tumor microenvironment (TME) negatively impacts tumor immunity and subsequently clinical outcomes. Therefore, there is a need to identify other checkpoint targets associated with the TME. Early-onset factors secreted by stromal cells as well as tumor cells often help recruit immune cells to the TME, among which are alarmins such as IL-33. The only known receptor for IL-33 is stimulation 2 (ST2). Here we demonstrated that high ST2 expression is associated with poor survival and is correlated with low CD8+ T cell cytotoxicity in CRC patients. ST2 is particularly expressed in tumor-associated macrophages (TAMs). In preclinical models of CRC, we demonstrated that ST2-expressing TAMs (ST2+ TAMs) were recruited into the tumor via CXCR3 expression and exacerbated the immunosuppressive TME; and that combination of ST2 depletion using ST2-KO mice with anti–programmed death 1 treatment resulted in profound growth inhibition of CRC. Finally, using the IL-33trap fusion protein, we suppressed CRC tumor growth and decreased tumor-infiltrating ST2+ TAMs. Together, our findings suggest that ST2 could serve as a potential checkpoint target for CRC immunotherapy.
Authors
Kevin Van der Jeught, Yifan Sun, Yuanzhang Fang, Zhuolong Zhou, Hua Jiang, Tao Yu, Jinfeng Yang, Malgorzata M. Kamocka, Ka Man So, Yujing Li, Haniyeh Eyvani, George E. Sandusky, Michael Frieden, Harald Braun, Rudi Beyaert, Xiaoming He, Xinna Zhang, Chi Zhang, Sophie Paczesny, Xiongbin Lu
Abstract
The loss of functional nephrons after kidney injury triggers the compensatory growth of the remaining ones to allow functional adaptation. However, in some cases, these compensatory events activate signaling pathways that lead to pathological alterations and chronic kidney disease. Little is known about the identity of these pathways and how they lead to the development of renal lesions. Here, we combined mouse strains that differently react to nephron reduction with molecular and temporal genome-wide transcriptome studies to elucidate the molecular mechanisms involved in these events. We demonstrated that nephron reduction led to 2 waves of cell proliferation: the first one occurred during the compensatory growth regardless of the genetic background, whereas the second one occurred, after a quiescent phase, exclusively in the sensitive strain and accompanied the development of renal lesions. Similarly, clustering by coinertia analysis revealed the existence of 2 waves of gene expression. Interestingly, we identified type I interferon (IFN) response as an early (first-wave) and specific signature of the sensitive (FVB/N) mice. Activation of type I IFN response was associated with G1/S cell cycle arrest, which correlated with p21 nuclear translocation. Remarkably, the transient induction of type I IFN response by poly(I:C) injections during the compensatory growth resulted in renal lesions in otherwise-resistant C57BL6 mice. Collectively, these results suggest that the early molecular and cellular events occurring after nephron reduction determine the risk of developing late renal lesions and point to type I IFN response as a crucial event of the deterioration process.
Authors
Mohamad Zaidan, Martine Burtin, Jitao David Zhang, Thomas Blanc, Pauline Barre, Serge Garbay, Clément Nguyen, Florence Vasseur, Lucie Yammine, Serena Germano, Laura Badi, Marie-Claire Gubler, Morgan Gallazzini, Gérard Friedlander, Marco Pontoglio, Fabiola Terzi
Abstract
Acute graft-versus-host disease (aGVHD) is a T cell–mediated immunological disorder and the leading cause of nonrelapse mortality in patients who receive allogeneic hematopoietic cell transplants. Based on recent observations that protein arginine methyltransferase 5 (PRMT5) and arginine methylation are upregulated in activated memory T cells, we hypothesized that PRMT5 is involved in the pathogenesis of aGVHD. Here, we show that PRMT5 expression and enzymatic activity were upregulated in activated T cells in vitro and in T cells from mice developing aGVHD after allogeneic transplant. PRMT5 expression was also upregulated in T cells of patients who developed aGVHD after allogeneic hematopoietic cell transplant compared with those who did not develop aGVHD. PRMT5 inhibition using a selective small-molecule inhibitor (C220) substantially reduced mouse and human allogeneic T cell proliferation and inflammatory IFN-γ and IL-17 cytokine production. Administration of PRMT5 small-molecule inhibitors substantially improves survival, reducing disease incidence and clinical severity in mouse models of aGVHD without adversely affecting engraftment. Importantly, we show that PRMT5 inhibition retained the beneficial graft-versus-leukemia effect by maintaining cytotoxic CD8+ T cell responses. Mechanistically, we show that PRMT5 inhibition potently reduced STAT1 phosphorylation as well as transcription of proinflammatory genes, including interferon-stimulated genes and IL-17. Additionally, PRMT5 inhibition deregulates the cell cycle in activated T cells and disrupts signaling by affecting ERK1/2 phosphorylation. Thus, we have identified PRMT5 as a regulator of T cell responses and as a therapeutic target in aGVHD.
Authors
Katiri J. Snyder, Nina C. Zitzer, Yandi Gao, Hannah K. Choe, Natalie E. Sell, Lotus Neidemire-Colley, Anora Ignaci, Charuta Kale, Raymond D. Devine, Maria G. Abad, Maciej Pietrzak, Min Wang, Hong Lin, Yang W. Zhang, Gregory K. Behbehani, Jane E. Jackman, Ramiro Garzon, Kris Vaddi, Robert A. Baiocchi, Parvathi Ranganathan
Abstract
BK channels are expressed in intercalated cells (ICs) and principal cells (PCs) in the cortical collecting duct (CCD) of the mammalian kidney and have been proposed to be responsible for flow-induced K+ secretion (FIKS) and K+ adaptation. To examine the IC-specific role of BK channels, we generated a mouse with targeted disruption of the pore-forming BK α subunit (BKα) in ICs (IC-BKα–KO). Whole cell charybdotoxin–sensitive (ChTX-sensitive) K+ currents were readily detected in control ICs but largely absent in ICs of IC-BKα–KO mice. When placed on a high K+ (HK) diet for 13 days, blood [K+] was significantly greater in IC-BKα–KO mice versus controls in males only, although urinary K+ excretion rates following isotonic volume expansion were similar in males and females. FIKS was present in microperfused CCDs isolated from controls but was absent in IC-BKα–KO CCDs of both sexes. Also, flow-stimulated epithelial Na+ channel–mediated (ENaC–mediated) Na+ absorption was greater in CCDs from female IC-BKα–KO mice than in CCDs from males. Our results confirm a critical role of IC BK channels in FIKS. Sex contributes to the capacity for adaptation to a HK diet in IC-BKα–KO mice.
Authors
Rolando Carrisoza-Gaytan, Evan C. Ray, Daniel Flores, Allison L. Marciszyn, Peng Wu, Leah Liu, Arohan R. Subramanya, WenHui Wang, Shaohu Sheng, Lubika J. Nkashama, Jingxin Chen, Edwin K. Jackson, Stephanie M. Mutchler, Szilvia Heja, Donald E. Kohan, Lisa M. Satlin, Thomas R. Kleyman
Abstract
Glucokinase (GK) is highly expressed in the hypothalamic paraventricular nucleus (PVN); however, its role is currently unknown. We found that GK in the PVN acts as part of a glucose-sensing mechanism within the PVN that regulates glucose homeostasis by controlling glucagon-like peptide 1 (GLP-1) release. GLP-1 is released from enteroendocrine L cells in response to oral glucose. Here we identify a brain mechanism critical to the release of GLP-1 in response to oral glucose. We show that increasing expression of GK or injection of glucose into the PVN increases GLP-1 release in response to oral glucose. On the contrary, decreasing expression of GK or injection of nonmetabolizable glucose into the PVN prevents GLP-1 release. Our results demonstrate that gluco-sensitive GK neurons in the PVN are critical to the response to oral glucose and subsequent release of GLP-1.
Authors
Yue Ma, Risheka Ratnasabapathy, Ivan De Backer, Chioma Izzi-Engbeaya, Marie-Sophie Nguyen-Tu, Joyceline Cuenco, Ben Jones, Christopher D. John, Brian Y.H. Lam, Guy A. Rutter, Giles S.H. Yeo, Waljit S. Dhillo, James Gardiner
Abstract
Heart failure (HF) remains a grievous illness with poor prognosis even with optimal care. The apelin receptor (APJ) counteracts the pressor effect of angiotensin II, attenuates ischemic injury, and has the potential to be a novel target to treat HF. Intravenous administration of apelin improves cardiac function acutely in patients with HF. However, its short half-life restricts its use to infusion therapy. To identify a longer acting APJ agonist, we conducted a medicinal chemistry campaign, leading to the discovery of potent small-molecule APJ agonists with comparable activity to apelin by mimicking the C-terminal portion of apelin-13. Acute infusion increased systolic function and reduced systemic vascular resistance in 2 rat models of impaired cardiac function. Similar results were obtained in an anesthetized but not a conscious canine HF model. Chronic oral dosing in a rat myocardial infarction model reduced myocardial collagen content and improved diastolic function to a similar extent as losartan, a RAS antagonist standard-of-care therapy, but lacked additivity with coadministration. Collectively, this work demonstrates the feasibility of developing clinical, viable, potent small-molecule agonists that mimic the endogenous APJ ligand with more favorable drug-like properties and highlights potential limitations for APJ agonism for this indication.
Authors
Brandon Ason, Yinhong Chen, Qi Guo, Kimberly M. Hoagland, Ray W. Chui, Mark Fielden, Weston Sutherland, Rhonda Chen, Ying Zhang, Shirley Mihardja, Xiaochuan Ma, Xun Li, Yaping Sun, Dongming Liu, Khanh Nguyen, Jinghong Wang, Ning Li, Sridharan Rajamani, Yusheng Qu, BaoXi Gao, Andrea Boden, Vishnu Chintalgattu, Jim R. Turk, Joyce Chan, Liaoyuan A. Hu, Paul Dransfield, Jonathan Houze, Jingman Wong, Ji Ma, Vatee Pattaropong, Murielle M. Véniant, Hugo M. Vargas, Gayathri Swaminath, Aarif Y. Khakoo
Abstract
Atrial fibrillation (AF) alters atrial cardiomyocyte (ACM) Ca2+ handling, promoting ectopic beat formation. We examined the effects of AF-associated remodeling on Ca2+-related action potential dynamics and consequences for AF susceptibility. AF was maintained electrically in dogs by right atrial (RA) tachypacing. ACMs isolated from AF dogs showed increased Ca2+ release refractoriness, spontaneous Ca2+ spark frequency, and cycle length (CL) threshold for Ca2+ and action potential duration (APD) alternans versus controls. AF increased the in situ CL threshold for Ca2+/APD alternans and spatial dispersion in Ca2+ release recovery kinetics, leading to spatially discordant alternans associated with reentrant rotor formation and susceptibility to AF induction/maintenance. The clinically available agent dantrolene reduced Ca2+ leak and CL threshold for Ca2+/APD alternans in ACMs and AF dog right atrium, while suppressing AF susceptibility; caffeine increased Ca2+ leak and CL threshold for Ca2+/APD alternans in control dog ACMs and RA tissues. In vivo, the atrial repolarization alternans CL threshold was increased in AF versus control, as was AF vulnerability. Intravenous dantrolene restored repolarization alternans threshold and reduced AF vulnerability. Immunoblots showed reduced expression of total and phosphorylated ryanodine receptors and calsequestrin in AF and unchanged phospholamban/SERCA expression. Thus, along with promoting spontaneous ectopy, AF-induced Ca2+ handling abnormalities favor AF by enhancing vulnerability to repolarization alternans, promoting initiation and maintenance of reentrant activity; dantrolene provides a lead molecule to target this mechanism.
Authors
Tao Liu, Feng Xiong, Xiao-Yan Qi, Jiening Xiao, Louis Villeneuve, Issam Abu-Taha, Dobromir Dobrev, Congxin Huang, Stanley Nattel
Abstract
Increased subchondral bone angiogenesis with blood vessels breaching the tidemark into the avascular cartilage is a diagnostic feature of human osteoarthritis. However, the mechanisms that initiate subchondral bone angiogenesis remain unclear. We show that abnormally increased platelet-derived growth factor–BB (PDGF-BB) secretion by mononuclear preosteoclasts induces subchondral bone angiogenesis, contributing to osteoarthritis development. In mice after destabilization of the medial meniscus (DMM), aberrant joint subchondral bone angiogenesis developed during an early stage of osteoarthritis, before articular cartilage damage occurred. Mononuclear preosteoclasts in subchondral bone secrete excessive amounts of PDGF-BB, which activates platelet-derived growth factor receptor–β (PDGFR-β) signaling in pericytes for neo-vessel formation. Selective knockout of PDGF-BB in preosteoclasts attenuates subchondral bone angiogenesis and abrogates joint degeneration and subchondral innervation induced by DMM. Transgenic mice that express PDGF-BB in preosteoclasts recapitulate pathological subchondral bone angiogenesis and develop joint degeneration and subchondral innervation spontaneously. Our study provides the first evidence to our knowledge that PDGF-BB derived from preosteoclasts is a key driver of pathological subchondral bone angiogenesis during osteoarthritis development and offers a new avenue for developing early treatments for this disease.
Authors
Weiping Su, Guanqiao Liu, Xiaonan Liu, Yangying Zhou, Qi Sun, Gehua Zhen, Xiao Wang, Yihe Hu, Peisong Gao, Shadpour Demehri, Xu Cao, Mei Wan
No posts were found with this tag.
