bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from Ribosomal Lesions Promote Oncogenic Mutagenesis
Authors: Sulima Sergey O. , Kampen Kim R. , Vereecke Stijn , Pepe Daniele , Fancello Laura , Verbeeck Jelle , Dinman Jonathan D. , De Keersmaecker Kim
Published: March 2023

Abstract
Ribosomopathies are congenital disorders caused by mutations in ribosomal proteins (RP) or assembly factors and are characterized by cellular hypoproliferation at an early stage. Paradoxically, many of these disorders have an elevated risk to progress to hyperproliferative cancer at a later stage. In addition, somatic RP mutations have recently been identified in various cancer types, for example, the recurrent RPL10-R98S mutation in T-cell acute lymphoblastic leukemia (T-ALL) and RPS15 mutations in chronic lymphocytic leukemia (CLL). We previously showed that RPL10-R98S promotes expression of oncogenes, but also induces a proliferative defect due to elevated oxidative stress. In this study, we demonstrate that this proliferation defect is eventually rescued by RPL10-R98S mouse lymphoid cells that acquire 5-fold more secondary mutations than RPL10-WT cells. The presence of RPL10-R98S and other RP mutations also correlated with a higher mutational load in patients with T-ALL, with an enrichment in NOTCH1-activating lesions. RPL10-R98S–associated cellular oxidative stress promoted DNA damage and impaired cell growth. Expression of NOTCH1 eliminated these phenotypes in RPL10-R98S cells, in part via downregulation of PKC-θ, with no effect on RPL10-WT cells. Patients with RP-mutant CLL also demonstrated a higher mutational burden, enriched for mutations that may diminish oxidative stress. We propose that oxidative stress due to ribosome dysfunction causes hypoproliferation and cellular insufficiency in ribosomopathies and RP-mutant cancer. This drives surviving cells, potentiated by genomic instability, to acquire rescuing mutations, which ultimately promote transition to hyperproliferation.
Significance:
Ribosomal lesions cause oxidative stress and increase mutagenesis, promoting acquisition of rescuing mutations that stimulate proliferation.
Data from Activation of PP2A and Inhibition of mTOR Synergistically Reduce MYC Signaling and Decrease Tumor Growth in Pancreatic Ductal Adenocarcinoma
Authors: Allen-Petersen Brittany L. , Risom Tyler , Feng Zipei , Wang Zhiping , Jenny Zina P. , Thoma Mary C. , Pelz Katherine R. , Morton Jennifer P. , Sansom Owen J. , Lopez Charles D. , Sheppard Brett , Christensen Dale J. , Ohlmeyer Michael , Narla Goutham , Sears Rosalie C.
Published: March 2023

Abstract
In cancer, kinases are often activated and phosphatases suppressed, leading to aberrant activation of signaling pathways driving cellular proliferation, survival, and therapeutic resistance. Although pancreatic ductal adenocarcinoma (PDA) has historically been refractory to kinase inhibition, therapeutic activation of phosphatases is emerging as a promising strategy to restore balance to these hyperactive signaling cascades. In this study, we hypothesized that phosphatase activation combined with kinase inhibition could deplete oncogenic survival signals to reduce tumor growth. We screened PDA cell lines for kinase inhibitors that could synergize with activation of protein phosphatase 2A (PP2A), a tumor suppressor phosphatase, and determined that activation of PP2A and inhibition of mTOR synergistically increase apoptosis and reduce oncogenic phenotypes in vitro and in vivo. This combination treatment resulted in suppression of AKT/mTOR signaling coupled with reduced expression of c-MYC, an oncoprotein implicated in tumor progression and therapeutic resistance. Forced expression of c-MYC or loss of PP2A B56α, the specific PP2A subunit shown to negatively regulate c-MYC, increased resistance to mTOR inhibition. Conversely, decreased c-MYC expression increased the sensitivity of PDA cells to mTOR inhibition. Together, these studies demonstrate that combined targeting of PP2A and mTOR suppresses proliferative signaling and induces cell death and implicates this combination as a promising therapeutic strategy for patients with PDA.
Significance:
These findings present a combinatorial strategy targeting serine/threonine protein phosphatase PP2A and mTOR in PDA, a cancer for which there are currently no targeted therapeutic options.
Data from 2-Hydroxyglutarate-Mediated Autophagy of the Endoplasmic Reticulum Leads to an Unusual Downregulation of Phospholipid Biosynthesis in Mutant IDH1 Gliomas
Authors: Viswanath Pavithra , Radoul Marina , Izquierdo-Garcia Jose Luis , Ong Wei Qiang , Luchman Hema Artee , Cairncross J. Gregory , Huang Bo , Pieper Russell O. , Phillips Joanna J. , Ronen Sabrina M.
Published: March 2023

Abstract
Tumor metabolism is reprogrammed to meet the demands of proliferating cancer cells. In particular, cancer cells upregulate synthesis of the membrane phospholipids phosphatidylcholine (PtdCho) and phosphatidylethanolamine (PtdE) in order to allow for rapid membrane turnover. Nonetheless, we show here that, in mutant isocitrate dehydrogenase 1 (IDHmut) gliomas, which produce the oncometabolite 2-hydroxyglutarate (2-HG), PtdCho and PtdE biosynthesis is downregulated and results in lower levels of both phospholipids when compared with wild-type IDH1 cells. 2-HG inhibited collagen-4-prolyl hydroxylase activity, leading to accumulation of misfolded procollagen-IV in the endoplasmic reticulum (ER) of both genetically engineered and patient-derived IDHmut glioma models. The resulting ER stress triggered increased expression of FAM134b, which mediated autophagic degradation of the ER (ER-phagy) and a reduction in the ER area. Because the ER is the site of phospholipid synthesis, ER-phagy led to reduced PtdCho and PtdE biosynthesis. Inhibition of ER-phagy via pharmacological or molecular approaches restored phospholipid biosynthesis in IDHmut glioma cells, triggered apoptotic cell death, inhibited tumor growth, and prolonged the survival of orthotopic IDHmut glioma-bearing mice, pointing to a potential therapeutic opportunity. Glioma patient biopsies also exhibited increased ER-phagy and downregulation of PtdCho and PtdE levels in IDHmut samples compared with wild-type, clinically validating our observations. Collectively, this study provides detailed and clinically relevant insights into the functional link between oncometabolite-driven ER-phagy and phospholipid biosynthesis in IDHmut gliomas.

Significance: Downregulation of phospholipid biosynthesis via ER-phagy is essential for proliferation and clonogenicity of mutant IDH1 gliomas, a finding with immediate therapeutic implications. Cancer Res; 78(9); 2290–304. ©2018 AACR.
Data from HER2 Overexpression Triggers an IL1α Proinflammatory Circuit to Drive Tumorigenesis and Promote Chemotherapy Resistance
Authors: Liu Shou , Lee Ji Shin , Jie Chunfa , Park Min Ho , Iwakura Yoichiro , Patel Yogin , Soni Mithil , Reisman David , Chen Hexin
Published: March 2023

Abstract
Systemic inflammation in breast cancer correlates with poor prognosis, but the molecular underpinnings of this connection are not well understood. In this study, we explored the relationship between HER2 overexpression, inflammation, and expansion of the mammary stem/progenitor and cancer stem–like cell (CSC) population in breast cancer. HER2-positive epithelial cells initiated and sustained an inflammatory milieu needed to promote tumorigenesis. HER2 induced a feedforward activation loop of IL1α and IL6 that stimulated NFκB and STAT3 pathways for generation and maintenance of breast CSC. In mice, Il1a genetic deficiency delayed MMTV-Her2–induced tumorigenesis and reduced inflammatory cytokine expression as well as CSC in primary tumors. In clinical specimens of human breast tumor tissues, tissue microarray analysis revealed a strong positive correlation between IL1α/IL6 expression and CSC-positive phenotype. Pharmacologic blockade of IL1α signaling reduced the CSC population and improved chemotherapeutic efficacy. Our findings suggest new therapeutic or prevention strategies for HER2-positive breast cancers.

Significance: IL1α signaling driven by HER2 promotes chronic inflammation needed to support cancer stem-like cell maintenance in HER2-positive breast cancers. Cancer Res; 78(8); 2040–51. ©2018 AACR.
Data from An ERG Enhancer–Based Reporter Identifies Leukemia Cells with Elevated Leukemogenic Potential Driven by ERG-USP9X Feed-Forward Regulation
Authors: Aqaqe Nasma , Yassin Muhammad , Yassin Abed Alkader , Ershaid Nour , Katz-Even Chen , Zipin-Roitman Adi , Kugler Eitan , Lechman Eric R. , Gan Olga I. , Mitchell Amanda , Dick John E. , Izraeli Shai , Milyavsky Michael
Published: March 2023

Abstract
Acute leukemia is a rapidly progressing blood cancer with low survival rates. Unfavorable prognosis is attributed to insufficiently characterized subpopulations of leukemia stem cells (LSC) that drive chemoresistance and leukemia relapse. Here we utilized a genetic reporter that assesses stemness to enrich and functionally characterize LSCs. We observed heterogeneous activity of the ERG+85 enhancer–based fluorescent reporter in human leukemias. Cells with high reporter activity (tagBFPHigh) exhibited elevated expression of stemness and chemoresistance genes and demonstrated increased clonogenicity and resistance to chemo- and radiotherapy as compared with their tagBFPNeg counterparts. The tagBFPHigh fraction was capable of regenerating the original cellular heterogeneity and demonstrated increased invasive ability. Moreover, the tagBFPHigh fraction was enriched for leukemia-initiating cells in a xenograft assay. We identified the ubiquitin hydrolase USP9X as a novel ERG transcriptional target that sustains ERG+85–positive cells by controlling ERG ubiquitination. Therapeutic targeting of USP9X led to preferential inhibition of the ERG-dependent leukemias. Collectively, these results characterize human leukemia cell functional heterogeneity and suggest that targeting ERG via USP9X inhibition may be a potential treatment strategy in patients with leukemia.
Significance:
This study couples a novel experimental tool with state-of-the-art approaches to delineate molecular mechanisms underlying stem cell-related characteristics in leukemia cells.
Data from Differential Subcellular Localization Regulates Oncogenic Signaling by ROS1 Kinase Fusion Proteins
Authors: Neel Dana S. , Allegakoen David V. , Olivas Victor , Mayekar Manasi K. , Hemmati Golzar , Chatterjee Nilanjana , Blakely Collin M. , McCoach Caroline E. , Rotow Julia K. , Le Anh , Karachaliou Niki , Rosell Rafael , Riess Jonathan W. , Nichols Robert , Doebele Robert C. , Bivona Trever G.
Published: March 2023

Abstract
Chromosomal rearrangements involving receptor tyrosine kinases (RTK) are a clinically relevant oncogenic mechanism in human cancers. These chimeric oncoproteins often contain the C-terminal kinase domain of the RTK joined in cis to various N-terminal, nonkinase fusion partners. The functional role of the N-terminal fusion partner in RTK fusion oncoproteins is poorly understood. Here, we show that distinct N-terminal fusion partners drive differential subcellular localization, which imparts distinct cell signaling and oncogenic properties of different, clinically relevant ROS1 RTK fusion oncoproteins. SDC4-ROS1 and SLC34A2-ROS1 fusion oncoproteins resided on endosomes and activated the MAPK pathway. CD74-ROS1 variants that localized instead to the endoplasmic reticulum (ER) showed compromised activation of MAPK. Forced relocalization of CD74-ROS1 from the ER to endosomes restored MAPK signaling. ROS1 fusion oncoproteins that better activate MAPK formed more aggressive tumors. Thus, differential subcellular localization controlled by the N-terminal fusion partner regulates the oncogenic mechanisms and output of certain RTK fusion oncoproteins.
Significance:
ROS1 fusion oncoproteins exhibit differential activation of MAPK signaling according to subcellular localization, with ROS1 fusions localized to endosomes, the strongest activators of MAPK signaling.
Data from A Large-Cohort, Longitudinal Study Determines Precancer Disease Routes across Different Cancer Types
Authors: Hu Jessica X. , Helleberg Marie , Jensen Anders B. , Brunak Søren , Lundgren Jens
Published: March 2023

Abstract
Although many diseases are associated with cancer, the full spectrum of temporal disease correlations across cancer types has not yet been characterized. A population-wide study of longitudinal disease trajectories is needed to interrogate the general medical histories of patients with cancer. Here we performed a retrospective study covering a 20-year period, using 6.9 million patients from the Danish National Patient Registry linked to 0.7 million patients with cancer from the Danish Cancer Registry. Statistical analysis identified all significant disease associations occurring prior to cancer diagnoses. These associations were used to build frequently occurring, longitudinal disease trajectories. Across 17 cancer types, a total of 648 significant diagnoses correlated directly with a cancer, while 168 diagnosis trajectories of time-ordered steps were identified for seven cancer types. The most common diseases across cancer types involved cardiovascular, obesity, and genitourinary diseases. A comprehensive, publicly available web tool of interactive illustrations for all cancer disease associations is provided. By exploring the precancer landscape using this large dataset, we identify disease associations that can be used to derive mechanistic hypotheses for future cancer research.
Significance:
This study offers an innovative approach to examine prediagnostic disease and cancer development in a large national population-based setting and provides a publicly available tool to foster additional cancer surveillance research.
Data from Dual Inhibition of GLUT1 and the ATR/CHK1 Kinase Axis Displays Synergistic Cytotoxicity in KRAS-Mutant Cancer Cells
Authors: Erber Johanna , Steiner Joachim D. , Isensee Jörg , Lobbes Leonard A. , Toschka André , Beleggia Filippo , Schmitt Anna , Kaiser Rainer W. J. , Siedek Florian , Persigehl Thorsten , Hucho Tim , Reinhardt Hans C.
Published: March 2023

Abstract
The advent of molecularly targeted therapeutic agents has opened a new era in cancer therapy. However, many tumors rely on nondruggable cancer-driving lesions. In addition, long-lasting clinical benefits from single-agent therapies rarely occur, as most of the tumors acquire resistance over time. The identification of targeted combination regimens interfering with signaling through oncogenically rewired pathways provides a promising approach to enhance efficacy of single-agent–targeted treatments. Moreover, combination drug therapies might overcome the emergence of drug resistance. Here, we performed a focused flow cytometry–based drug synergy screen and identified a novel synergistic interaction between GLUT1-mediated glucose transport and the cell-cycle checkpoint kinases ATR and CHK1. Combined inhibition of CHK1/GLUT1 or ATR/GLUT1 robustly induced apoptosis, particularly in RAS-mutant cancer cells. Mechanistically, combined inhibition of ATR/CHK1 and GLUT1 arrested sensitive cells in S-phase and led to the accumulation of genotoxic damage, particularly in S-phase. In vivo, simultaneous inhibition of ATR and GLUT1 significantly reduced tumor volume gain in an autochthonous mouse model of KrasG12D-driven soft tissue sarcoma. Taken together, these findings pave the way for combined inhibition of GLUT1 and ATR/CHK1 as a therapeutic approach for KRAS-driven cancers.
Significance:
Dual targeting of the DNA damage response and glucose transport synergistically induces apoptosis in KRAS-mutant cancer, suggesting this combination treatment for clinical validation in KRAS-stratified tumor patients.
Data from IDO1 and Kynurenine Pathway Metabolites Activate PI3K-Akt Signaling in the Neoplastic Colon Epithelium to Promote Cancer Cell Proliferation and Inhibit Apoptosis
Authors: Bishnupuri Kumar S. , Alvarado David M. , Khouri Alexander N. , Shabsovich Mark , Chen Baosheng , Dieckgraefe Brian K. , Ciorba Matthew A.
Published: March 2023

Abstract
The tryptophan-metabolizing enzyme indoleamine 2,3 dioxygenase 1 (IDO1) is frequently overexpressed in epithelial-derived malignancies, where it plays a recognized role in promoting tumor immune tolerance. We previously demonstrated that the IDO1–kynurenine pathway (KP) also directly supports colorectal cancer growth by promoting activation of β-catenin and driving neoplastic growth in mice lacking intact adaptive immunity. In this study, we sought to delineate the specific role of epithelial IDO1 in colon tumorigenesis and define how IDO1 and KP metabolites interact with pivotal neoplastic signaling pathways of the colon epithelium. We generated a novel intestinal epithelial–specific IDO1 knockout mouse and utilized established colorectal cancer cell lines containing β-catenin–stabilizing mutations, human colorectal cancer samples, and human-derived epithelial organoids (colonoids and tumoroids). Mice with intestinal epithelial–specific knockout of IDO1 developed fewer and smaller tumors than wild-type littermates in a model of inflammation-driven colon tumorigenesis. Moreover, their tumors exhibited reduced nuclear β-catenin and neoplastic proliferation but increased apoptosis. Mechanistically, KP metabolites (except kynurenic acid) rapidly activated PI3K-Akt signaling in the neoplastic epithelium to promote nuclear translocation of β-catenin, cellular proliferation, and resistance to apoptosis. Together, these data define a novel cell-autonomous function and mechanism by which IDO1 activity promotes colorectal cancer progression. These findings may have implications for the rational design of new clinical trials that exploit a synergy of IDO1 inhibitors with conventional cancer therapies for which Akt activation provides resistance such as radiation.

Significance: This study identifies a new mechanistic link between IDO1 activity and PI3K/AKT signaling, both of which are important pathways involved in cancer growth and resistance to cancer therapy.
Data from Cys34 Adductomics Links Colorectal Cancer with the Gut Microbiota and Redox Biology
Authors: Grigoryan Hasmik , Schiffman Courtney , Gunter Marc J. , Naccarati Alessio , Polidoro Silvia , Dagnino Sonia , Dudoit Sandrine , Vineis Paolo , Rappaport Stephen M.
Published: March 2023

Abstract
Chronic inflammation is an established risk factor for colorectal cancer. To study reactive products of gut inflammation and redox signaling on colorectal cancer development, we used untargeted adductomics to detect adduct features in prediagnostic serum from the EPIC Italy cohort. We focused on modifications to Cys34 in human serum albumin, which is responsible for scavenging small reactive electrophiles that might initiate cancers. Employing a combination of statistical methods, we selected seven Cys34 adducts associated with colorectal cancer, as well as body mass index (BMI; a well-known risk factor). Five adducts were more abundant in colorectal cancer cases than controls and clustered with each other, suggesting a common pathway. Because two of these adducts were Cys34 modifications by methanethiol, a microbial–human cometabolite, and crotonaldehyde, a product of lipid peroxidation, these findings further implicate infiltration of gut microbes into the intestinal mucosa and the corresponding inflammatory response as causes of colorectal cancer. The other two associated adducts were Cys34 disulfides of homocysteine that were less abundant in colorectal cancer cases than controls and may implicate homocysteine metabolism as another causal pathway. The selected adducts and BMI ranked higher as potentially causal factors than variables previously associated with colorectal cancer (smoking, alcohol consumption, physical activity, and total meat consumption). Regressions of case–control differences in adduct levels on days to diagnosis showed no statistical evidence that disease progression, rather than causal factors at recruitment, contributed to the observed differences. These findings support the hypothesis that infiltration of gut microbes into the intestinal mucosa and the resulting inflammation are causal factors for colorectal cancer.
Significance:
Infiltration of gut microbes into the intestinal mucosa and the resulting inflammation are causal factors for colorectal cancer.
Data from Metastatic Tumor-in-a-Dish, a Novel Multicellular Organoid to Study Lung Colonization and Predict Therapeutic Response
Authors: Ramamoorthy Prabhu , Thomas Sufi Mary , Kaushik Gaurav , Subramaniam Dharmalingam , Chastain Katherine M. , Dhar Animesh , Tawfik Ossama , Kasi Anup , Sun Weijing , Ramalingam Satish , Gunewardena Sumedha , Umar Shahid , Mammen Joshua M. , Padhye Subhash B. , Weir Scott J. , Jensen Roy A. , Sittampalam G. Sitta , Anant Shrikant
Published: March 2023

Abstract
Metastasis is a major cause of cancer-related deaths. A dearth of preclinical models that recapitulate the metastatic microenvironment has impeded the development of therapeutic agents that are effective against metastatic disease. Because the majority of solid tumors metastasize to the lung, we developed a multicellular lung organoid that mimics the lung microenvironment with air sac–like structures and production of lung surfactant protein. We used these cultures, called primitive lung-in-a-dish (PLiD), to recreate metastatic disease using primary and established cancer cells. The metastatic tumor-in-a-dish (mTiD) cultures resemble the architecture of metastatic tumors in the lung, including angiogenesis. Pretreating PLiD with tumor exosomes enhanced cancer cell colonization. We next tested the response of primary and established cancer cells to current chemotherapeutic agents and an anti-VEGF antibody in mTiD against cancer cells in two-dimensional (2D) or 3D cultures. The response of primary patient-derived colon and ovarian tumor cells to therapy in mTiD cultures matched the response of the patient in the clinic, but not in 2D or single-cell–type 3D cultures. The sensitive mTiD cultures also produced significantly lower circulating markers for cancer similar to that seen in patients who responded to therapy. Thus, we have developed a novel method for lung colonization in vitro, a final stage in tumor metastasis. Moreover, the technique has significant utility in precision/personalized medicine, wherein this phenotypic screen can be coupled with current DNA pharmacogenetics to identify the ideal therapeutic agent, thereby increasing the probability of response to treatment while reducing unnecessary side effects.
Significance:
A lung organoid that exhibits characteristics of a normal human lung is developed to study the biology of metastatic disease and therapeutic intervention.
Data from ERRα Expression in Bone Metastases Leads to an Exacerbated Antitumor Immune Response
Authors: Bouchet Mathilde , Lainé Alexandra , Boyault Cyril , Proponnet-Guerault Mathilde , Meugnier Emmanuelle , Bouazza Lamia , Kan Casina W.S. , Geraci Sandra , El-Moghrabi Soumaya , Hernandez-Vargas Hector , Benetollo Claire , Yoshiko Yuji , Duterque-Coquillaud Martine , Clézardin Philippe , Marie Julien C. , Bonnelye Edith
Published: March 2023

Abstract
Bone is the most common metastatic site for breast cancer. Although the estrogen-related receptor alpha (ERRα) has been implicated in breast cancer cell dissemination to the bone from the primary tumor, its role after tumor cell anchorage in the bone microenvironment remains elusive. Here, we reveal that ERRα inhibits the progression of bone metastases of breast cancer cells by increasing the immune activity of the bone microenvironment. Overexpression of ERRα in breast cancer bone metastases induced expression of chemokines CCL17 and CCL20 and repressed production of TGFβ3. Subsequently, CD8+ T lymphocytes recruited to bone metastases escaped TGFβ signaling control and were endowed with exacerbated cytotoxic features, resulting in significant reduction in metastases. The clinical relevance of our findings in mice was confirmed in over 240 patients with breast cancer. Thus, this study reveals that ERRα regulates immune properties in the bone microenvironment that contributes to decreasing metastatic growth.
Significance:
This study places ERRα at the interplay between the immune response and bone metastases of breast cancer, highlighting a potential target for intervention in advanced disease.
Data from A Single-Step, High-Dose Selection Scheme Reveals Distinct Mechanisms of Acquired Resistance to Oncogenic Kinase Inhibition in Cancer Cells
Authors: Finn Kenneth J. , Martin Scott E. , Settleman Jeff
Published: March 2023

Abstract
Despite the remarkable clinical efficacy demonstrated by molecularly targeted cancer therapeutics, the benefits are typically temporary due to the emergence of acquired drug resistance. This has spurred a massive effort by the cancer research community to identify mechanisms used by cancer cells to evade treatment. Among the various methodologies developed and employed to identify such mechanisms, the most commonly used approach has been to model acquired resistance by exposing cancer cells in culture to gradually increasing concentrations of drug over an extended period of time. Here, we employed a less commonly used variation on this approach, wherein resistant cells are selected by immediately exposing cancer cells to a continuous, high concentration of drug. Using this approach, we isolated clones representing three distinct mechanisms of resistance to inhibition of MET kinase activity from a single clonally derived cancer cell line. The emergent clones had acquired resistance through engagement of alternative receptor tyrosine kinases either through upregulation of FGF3 or HBEGF or increased MAPK signaling through an activating V600E mutation in BRAF. Importantly, these mechanisms were not identified using the conventional “ramp-up” approach in previous studies that employed the same cell line. These results suggest that the particular nature of the selection scheme employed in cell culture modeling studies can determine which potential resistance mechanisms are identified and which ones may be missed, highlighting the need for careful consideration of the specific approach used to model resistance in cultured cells.
Significance:
Through modeling resistance to MET kinase inhibition in cultured cancer cells using single-step, high-dose selection, these findings highlight that the specific nature of the selection protocol impacts which resistance mechanisms are identified.

See related commentary by Floros et al., p. 25
Data from The Lymphatic Cell Environment Promotes Kaposi Sarcoma Development by Prox1-Enhanced Productive Lytic Replication of Kaposi Sarcoma Herpes Virus
Authors: Choi Dongwon , Park Eunkyung , Kim Kyu Eui , Jung Eunson , Seong Young Jin , Zhao Luping , Madhavan Shrimika , Daghlian George , Lee Hansuh H. , Daghlian Patill T. , Daghlian Saren , Bui Khoa , Koh Chester J. , Wong Alex K. , Cho Il-Taeg , Hong Young-Kwon
Published: March 2023

Abstract
Kaposi sarcoma is the most common cancer in human immunodeficiency virus–positive individuals and is caused by Kaposi sarcoma–associated herpesvirus (KSHV). It is believed that a small number of latently infected Kaposi sarcoma tumor cells undergo spontaneous lytic reactivation to produce viral progeny for infection of new cells. Here, we use matched donor-derived human dermal blood and lymphatic endothelial cells (BEC and LEC, respectively) to show that KSHV-infected BECs progressively lose viral genome as they proliferate. In sharp contrast, KSHV-infected LECs predominantly entered lytic replication, underwent cell lysis, and released new virus. Continuous lytic cell lysis and de novo infection allowed LEC culture to remain infected for a prolonged time. Because of the strong propensity of LECs toward lytic replication, LECs maintained virus as a population, despite the death of individual host cells from lytic lysis. The master regulator of lymphatic development, Prox1, bound the promoter of the RTA gene to upregulate its expression and physically interacted with RTA protein to coregulate lytic genes. Thus, LECs may serve as a proficient viral reservoir that provides viral progeny for continuous de novo infection of tumor origin cells, and potentially BECs and mesenchymal stem cells, which give rise to Kaposi sarcoma tumors. Our study reveals drastically different host cell behaviors between BEC and LEC and defines the underlying mechanisms of the lymphatic cell environment supporting persistent infection in Kaposi sarcoma tumors.
Significance:
This study defines the mechanism by which Kaposi's sarcoma could be maintained by virus constantly produced by lymphatic cells in HIV-positive individuals.
Data from Disruption of Endolysosomal RAB5/7 Efficiently Eliminates Colorectal Cancer Stem Cells
Authors: Takeda Mitsunobu , Koseki Jun , Takahashi Hidekazu , Miyoshi Norikatsu , Nishida Naohiro , Nishimura Junichi , Hata Taishi , Matsuda Chu , Mizushima Tsunekazu , Yamamoto Hirofumi , Ishii Hideshi , Doki Yuichiro , Mori Masaki , Haraguchi Naotsugu
Published: March 2023

Abstract
Given that cancer stem cells (CSC) play a key role in drug resistance and relapse, targeting CSCs remains promising in cancer therapy. Here we show that RAB5/7, which are involved in the endolysosomal pathway, play key roles in the maintenance of CSC survival via regulation of the mitophagic pathway. Inhibition of RAB5/7 efficiently eliminated colorectal CSCs and disrupted cancer foci. In addition, we identified mefloquine hydrochloride, an antimalarial drug, as a novel RAB5/7 inhibitor and promising colorectal CSC-targeting drug. Endolysosomal RAB5/7 and LAMP1/2 mediated parkin-dependent mitochondrial clearance and modulated mitophagy through lysosomal dynamics. In a patient-derived xenograft (PDX) model of colon cancer, treatment with mefloquine resulted in suppression of mitophagic PINK1/PARKIN and increased mitochondrial disorder and mitochondria-induced apoptosis without apparent side effects. These results suggest that the combination of mefloquine with chemotherapeutic agents in the PDX model potentially disrupts the hierarchy of colorectal cancer cells and identify endolysosomal RAB5/7 and LAMP1/2 as promising therapeutic targets in CSCs.
Significance:
These findings show that endosomal/lysosomal RAB5 and RAB7, which regulate mitophagy, are essential for the survival of colon cancer stem cells.
Data from IRE1α Disruption in Triple-Negative Breast Cancer Cooperates with Antiangiogenic Therapy by Reversing ER Stress Adaptation and Remodeling the Tumor Microenvironment
Authors: Harnoss Jonathan M. , Le Thomas Adrien , Reichelt Mike , Guttman Ofer , Wu Thomas D. , Marsters Scot A. , Shemorry Anna , Lawrence David A. , Kan David , Segal Ehud , Merchant Mark , Totpal Klara , Crocker Lisa M. , Mesh Kathryn , Dohse Monika , Solon Margaret , Modrusan Zora , Rudolph Joachim , Koeppen Hartmut , Walter Peter , Ashkenazi Avi
Published: March 2023

Abstract
Cancer cells exploit the unfolded protein response (UPR) to mitigate endoplasmic reticulum (ER) stress caused by cellular oncogene activation and a hostile tumor microenvironment (TME). The key UPR sensor IRE1α resides in the ER and deploys a cytoplasmic kinase–endoribonuclease module to activate the transcription factor XBP1s, which facilitates ER-mediated protein folding. Studies of triple-negative breast cancer (TNBC)—a highly aggressive malignancy with a dismal posttreatment prognosis—implicate XBP1s in promoting tumor vascularization and progression. However, it remains unknown whether IRE1α adapts the ER in TNBC cells and modulates their TME, and whether IRE1α inhibition can enhance antiangiogenic therapy—previously found to be ineffective in patients with TNBC. To gauge IRE1α function, we defined an XBP1s-dependent gene signature, which revealed significant IRE1α pathway activation in multiple solid cancers, including TNBC. IRE1α knockout in TNBC cells markedly reversed substantial ultrastructural expansion of their ER upon growth in vivo. IRE1α disruption also led to significant remodeling of the cellular TME, increasing pericyte numbers while decreasing cancer-associated fibroblasts and myeloid-derived suppressor cells. Pharmacologic IRE1α kinase inhibition strongly attenuated growth of cell line–based and patient-derived TNBC xenografts in mice and synergized with anti-VEGFA treatment to cause tumor stasis or regression. Thus, TNBC cells critically rely on IRE1α to adapt their ER to in vivo stress and to adjust the TME to facilitate malignant growth. TNBC reliance on IRE1α is an important vulnerability that can be uniquely exploited in combination with antiangiogenic therapy as a promising new biologic approach to combat this lethal disease.
Significance:
Pharmacologic IRE1α kinase inhibition reverses ultrastructural distension of the ER, normalizes the tumor vasculature, and remodels the cellular TME, attenuating TNBC growth in mice.
Data from Systematic Establishment of Robustness and Standards in Patient-Derived Xenograft Experiments and Analysis
Authors: Evrard Yvonne A. , Srivastava Anuj , Randjelovic Jelena , Doroshow James H. , Dean Dennis A. , Morris Jeffrey S. , Chuang Jeffrey H.
Published: March 2023

Abstract
Patient-derived xenografts (PDX) are tumor-in-mouse models for cancer. PDX collections, such as the NCI PDXNet, are powerful resources for preclinical therapeutic testing. However, variations in experimental and analysis procedures have limited interpretability. To determine the robustness of PDX studies, the PDXNet tested temozolomide drug response for three prevalidated PDX models (sensitive, resistant, and intermediate) across four blinded PDX Development and Trial Centers using independently selected standard operating procedures. Each PDTC was able to correctly identify the sensitive, resistant, and intermediate models, and statistical evaluations were concordant across all groups. We also developed and benchmarked optimized PDX informatics pipelines, and these yielded robust assessments across xenograft biological replicates. These studies show that PDX drug responses and sequence results are reproducible across diverse experimental protocols. In addition, we share the range of experimental procedures that maintained robustness, as well as standardized cloud-based workflows for PDX exome-sequencing and RNA-sequencing analyses and for evaluating growth.
Significance:
The PDXNet Consortium shows that PDX drug responses and sequencing results are reproducible across diverse experimental protocols, establishing the potential for multisite preclinical studies to translate into clinical trials.
Data from BRD4 Levels Determine the Response of Human Lung Cancer Cells to BET Degraders That Potently Induce Apoptosis through Suppression of Mcl-1
Authors: Zong Dan , Gu Jiajia , Cavalcante Giovanna C. , Yao Weilong , Zhang Guojing , Wang Shaomeng , Owonikoko Taofeek K. , He Xia , Sun Shi-Yong
Published: March 2023

Abstract
Lung cancer consists of approximately 80% non–small cell lung cancer (NSCLC) and 20% small cell lung cancer (SCLC) and remains the leading cause of cancer-related deaths worldwide despite advances in early diagnosis, targeted therapy, and immunotherapy. Thus, novel therapies are still urgently needed. Bromodomain and extraterminal (BET) proteins, primarily comprised of BRD2, BRD3, and BRD4 proteins, function as epigenetic readers and master transcription coactivators and are now recognized cancer therapeutic targets. BET degraders such as ZBC260 and dBET represent a novel class of BET inhibitors that act by inducing BET degradation. The current study demonstrates the therapeutic efficacies of BET degraders, particularly ZBC260, against lung cancer, as well as understanding the underlying mechanisms and identifying molecular markers that determine cell sensitivity to BET degraders. A panel of NSCLC cell lines possessed similar response patterns to ZBC260 and dBET but different responses to BET inhibitor JQ-1. BRD levels, particularly BRD4, correlated positively with high sensitivity to BET degraders but not to JQ-1. BET degraders potently induced apoptosis in sensitive NSCLC cells and were accompanied by reduction of Mcl-1 and c-FLIP levels, which are critical for mediating induction of apoptosis and enhancement of TRAIL-induced apoptosis. Accordingly, ZBC260 exerted more potent activity than JQ-1 in vivo against the growth of NSCLC xenografts and patient-derived xenografts. These findings warrant future clinical validation of the efficacy of BET degraders in NSCLC, particularly those with high levels of BRD proteins, especially BRD4.
Significance:
The current study demonstrates the potential of novel BET degraders in the treatment of lung cancer and warrants clinical validation of BET degraders in lung cancer with high levels of BRD4.
Data from Nod1 Imprints Inflammatory and Carcinogenic Responses toward the Gastric Pathogen Helicobacter pylori
Authors: Suarez Giovanni , Romero-Gallo Judith , Piazuelo Maria B. , Sierra Johanna C. , Delgado Alberto G. , Washington M. Kay , Shah Shailja C. , Wilson Keith T. , Peek Richard M.
Published: March 2023

Abstract
Helicobacter pylori (H. pylori) is the strongest known risk for gastric cancer. The H. pylori cag type IV secretion system is an oncogenic locus that translocates peptidoglycan into host cells, where it is recognized by NOD1, an innate immune receptor. Beyond this, the role of NOD1 in H. pylori–induced cancer remains undefined. To address this knowledge gap, we infected two genetic models of Nod1 deficiency with the H. pylori cag+ strain PMSS1: C57BL/6 mice, which rarely develop cancer, and INS-GAS FVB/N mice, which commonly develop cancer. Infected C57BL/6Nod1–/− and INS-GASNod1−/− mice acutely developed more severe gastritis, and INS-GASNod1−/− mice developed gastric dysplasia more frequently compared with Nod1+/+ mice. Because Nod1 genotype status did not alter microbial phenotypes of in vivo–adapted H. pylori, we investigated host immunologic responses. H. pylori infection of Nod1−/− mice led to significantly increased gastric mucosal levels of Th1, Th17, and Th2 cytokines compared with Nod1 wild-type (WT) mice. To define the role of specific innate immune cells, we quantified cytokine secretion from H. pylori–infected primary gastric organoids generated from WT or Nod1−/− mice that were cocultured with or without WT or Nod1−/− macrophages. Infection increased cytokine production from gastric epithelial cells and macrophages and elevations were significantly increased with Nod1 deficiency. Furthermore, H. pylori infection altered the polarization status of Nod1−/− macrophages compared with Nod1+/+ macrophages. Collectively, these studies demonstrate that loss of Nod1 augments inflammatory and injury responses to H. pylori. Nod1 may exert its restrictive role by altering macrophage polarization, leading to immune evasion and microbial persistence.
Significance:
These findings suggest that manipulation of NOD1 may represent a novel strategy to prevent or treat pathologic outcomes induced by H. pylori infection.
Data from A Functional Landscape of Resistance to MEK1/2 and CDK4/6 Inhibition in NRAS-Mutant Melanoma
Authors: Hayes Tikvah K. , Luo Flora , Cohen Ofir , Goodale Amy B. , Lee Yenarae , Pantel Sasha , Bagul Mukta , Piccioni Federica , Root David E. , Garraway Levi A. , Meyerson Matthew , Johannessen Cory M.
Published: March 2023

Abstract
Combinatorial inhibition of MEK1/2 and CDK4/6 is currently undergoing clinical investigation in NRAS-mutant melanoma. To prospectively map the landscape of resistance to this investigational regimen, we utilized a series of gain- and loss-of-function forward genetic screens to identify modulators of resistance to clinical inhibitors of MEK1/2 and CDK4/6 alone and in combination. First, we identified NRAS-mutant melanoma cell lines that were dependent on NRAS for proliferation and sensitive to MEK1/2 and CDK4/6 combination treatment. We then used a genome-scale ORF overexpression screen and a CRISPR knockout screen to identify modulators of resistance to each inhibitor alone or in combination. These orthogonal screening approaches revealed concordant means of achieving resistance to this therapeutic modality, including tyrosine kinases, RAF, RAS, AKT, and PI3K signaling. Activated KRAS was sufficient to cause resistance to combined MEK/CDK inhibition and to replace genetic depletion of oncogenic NRAS. In summary, our comprehensive functional genetic screening approach revealed modulation of resistance to the inhibition of MEK1/2, CDK4/6, or their combination in NRAS-mutant melanoma.
Significance:
These findings reveal that NRAS-mutant melanomas can acquire resistance to genetic ablation of NRAS or combination MEK1/2 and CDK4/6 inhibition by upregulating activity of the RTK–RAS–RAF and RTK–PI3K–AKT signaling cascade.
Data from Autocrine IL6-Mediated Activation of the STAT3–DNMT Axis Silences the TNFα–RIP1 Necroptosis Pathway to Sustain Survival and Accumulation of Myeloid-Derived Suppressor Cells
Authors: Smith Alyssa D. , Lu Chunwan , Payne Daniela , Paschall Amy V. , Klement John D. , Redd Priscilla S. , Ibrahim Mohammed L. , Yang Dafeng , Han Qimei , Liu Zhuoqi , Shi Huidong , Hartney Thomas J. , Nayak-Kapoor Asha , Liu Kebin
Published: March 2023

Abstract
Although accumulation of myeloid-derived suppressor cells (MDSC) is a hallmark of cancer, the underlying mechanism of this accumulation within the tumor microenvironment remains incompletely understood. We report here that TNFα–RIP1–mediated necroptosis regulates accumulation of MDSCs. In tumor-bearing mice, pharmacologic inhibition of DNMT with the DNA methyltransferease inhibitor decitabine (DAC) decreased MDSC accumulation and increased activation of antigen-specific cytotoxic T lymphocytes. DAC-induced decreases in MDSC accumulation correlated with increased expression of the myeloid cell lineage-specific transcription factor IRF8 in MDSCs. However, DAC also suppressed MDSC-like cell accumulation in IRF8-deficient mice, indicating that DNA methylation may regulate MDSC survival through an IRF8-independent mechanism. Instead, DAC decreased MDSC accumulation by increasing cell death via disrupting DNA methylation of RIP1-dependent targets of necroptosis. Genome-wide DNA bisulfite sequencing revealed that the Tnf promoter was hypermethylated in tumor-induced MDSCs in vivo. DAC treatment dramatically increased TNFα levels in MDSC in vitro, and neutralizing TNFα significantly increased MDSC accumulation and tumor growth in tumor-bearing mice in vivo. Recombinant TNFα induced MDSC cell death in a dose- and RIP1-dependent manner. IL6 was abundantly expressed in MDSCs in tumor-bearing mice and patients with human colorectal cancer. In vitro, IL6 treatment of MDSC-like cells activated STAT3, increased expression of DNMT1 and DNMT3b, and enhanced survival. Overall, our findings reveal that MDSCs establish a STAT3–DNMT epigenetic axis, regulated by autocrine IL6, to silence TNFα expression. This results in decreased TNFα-induced and RIP1-dependent necroptosis to sustain survival and accumulation.
Significance:
These findings demonstrate that targeting IL6 expression or function represent potentially effective approaches to suppress MDSC survival and accumulation in the tumor microenvironment.
Data from TET2-Dependent Hydroxymethylome Plasticity Reduces Melanoma Initiation and Progression
Authors: Bonvin Elise , Radaelli Enrico , Bizet Martin , Luciani Flavie , Calonne Emilie , Putmans Pascale , Nittner David , Singh Nitesh Kumar , Santagostino Sara Francesca , Petit Valérie , Larue Lionel , Marine Jean Christophe , Fuks François
Published: March 2023

Abstract
Although numerous epigenetic aberrancies accumulate in melanoma, their contribution to initiation and progression remain unclear. The epigenetic mark 5-hydroxymethylcytosine (5hmC), generated through TET-mediated DNA modification, is now referred to as the sixth base of DNA and has recently been reported as a potential biomarker for multiple types of cancer. Loss of 5hmC is an epigenetic hallmark of melanoma, but whether a decrease in 5hmc levels contributes directly to pathogenesis or whether it merely results from disease progression–associated epigenetic remodeling remains to be established. Here, we show that NRAS-driven melanomagenesis in mice is accompanied by an overall decrease in 5hmC and specific 5hmC gains in selected gene bodies. Strikingly, genetic ablation of Tet2 in mice cooperated with oncogenic NRASQ61K to promote melanoma initiation while suppressing specific gains in 5hmC. We conclude that TET2 acts as a barrier to melanoma initiation and progression, partly by promoting 5hmC gains in specific gene bodies.
Significance:
This work emphasizes the importance of epigenome plasticity in cancer development and highlights the involvement of druggable epigenetic factors in cancer.
Data from Nicotinamide Phosphoribosyltransferase Acts as a Metabolic Gate for Mobilization of Myeloid-Derived Suppressor Cells
Authors: Travelli Cristina , Consonni Francesca Maria , Sangaletti Sabina , Storto Mariangela , Morlacchi Sara , Grolla Ambra A. , Galli Ubaldina , Tron Gian Cesare , Portararo Paola , Rimassa Lorenza , Pressiani Tiziana , Mazzone Massimiliano , Trovato Rosalinda , Ugel Stefano , Bronte Vincenzo , Tripodo Claudio , Colombo Mario P. , Genazzani Armando A. , Sica Antonio
Published: March 2023

Abstract
Cancer induces alteration of hematopoiesis to fuel disease progression. We report that in tumor-bearing mice the macrophage colony-stimulating factor elevates the myeloid cell levels of nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting enzyme in the NAD salvage pathway, which acts as negative regulator of the CXCR4 retention axis of hematopoietic cells in the bone marrow. NAMPT inhibits CXCR4 through a NAD/Sirtuin 1–mediated inactivation of HIF1α-driven CXCR4 gene transcription, leading to mobilization of immature myeloid-derived suppressor cells (MDSC) and enhancing their production of suppressive nitric oxide. Pharmacologic inhibition or myeloid-specific ablation of NAMPT prevented MDSC mobilization, reactivated specific antitumor immunity, and enhanced the antitumor activity of immune checkpoint inhibitors. Our findings identify NAMPT as a metabolic gate of MDSC precursor function, providing new opportunities to reverse tumor immunosuppression and to restore clinical efficacy of immunotherapy in patients with cancer.
Significance:
These findings identify NAMPT as a metabolic gate of MDSC precursor function, providing new opportunities to reverse tumor immunosuppression and to restore clinical efficacy of immunotherapy in cancer patients.