Mast cells mediate malignant pleural effusion formation

• Text
• PDF

Abstract

Mast cells (MCs) have been identified in various tumors; however, the role of these cells in tumorigenesis remains controversial. Here, we quantified MCs in human and murine malignant pleural effusions (MPEs) and evaluated the fate and function of these cells in MPE development. Evaluation of murine MPE-competent lung and colon adenocarcinomas revealed that these tumors actively attract and subsequently degranulate MCs in the pleural space by elaborating CCL2 and osteopontin. MCs were required for effusion development, as MPEs did not form in mice lacking MCs, and pleural infusion of MCs with MPE-incompetent cells promoted MPE formation. Once homed to the pleural space, MCs released tryptase AB1 and IL-1β, which in turn induced pleural vasculature leakiness and triggered NF-κB activation in pleural tumor cells, thereby fostering pleural fluid accumulation and tumor growth. Evaluation of human effusions revealed that MCs are elevated in MPEs compared with benign effusions. Moreover, MC abundance correlated with MPE formation in a human cancer cell–induced effusion model. Treatment of mice with the c-KIT inhibitor imatinib mesylate limited effusion precipitation by mouse and human adenocarcinoma cells. Together, the results of this study indicate that MCs are required for MPE formation and suggest that MC-dependent effusion formation is therapeutically addressable.

Authors

Anastasios D. Giannou, Antonia Marazioti, Magda Spella, Nikolaos I. Kanellakis, Hara Apostolopoulou, Ioannis Psallidas, Zeljko M. Prijovich, Malamati Vreka, Dimitra E. Zazara, Ioannis Lilis, Vassilios Papaleonidopoulos, Chrysoula A. Kairi, Alexandra L. Patmanidi, Ioanna Giopanou, Nikolitsa Spiropoulou, Vaggelis Harokopos, Vassilis Aidinis, Dionisios Spyratos, Stamatia Teliousi, Helen Papadaki, Stavros Taraviras, Linda A. Snyder, Oliver Eickelberg, Dimitrios Kardamakis, Yoichiro Iwakura, Thorsten B. Feyerabend, Hans-Reimer Rodewald, Ioannis Kalomenidis, Timothy S. Blackwell, Theodora Agalioti, Georgios T. Stathopoulos

Immunosurveillance and therapy of multiple myeloma are CD226 dependent

• Text
• PDF

Abstract

Multiple myeloma (MM) is an age-dependent hematological malignancy. Evaluation of immune interactions that drive MM relies on in vitro experiments that do not reflect the complex cellular stroma involved in MM pathogenesis. Here we used Vk*MYC transgenic mice, which spontaneously develop MM, and demonstrated that the immune system plays a critical role in the control of MM progression and the response to treatment. We monitored Vk*MYC mice that had been crossed with Cd226 mutant mice over a period of 3 years and found that CD226 limits spontaneous MM development. The CD226-dependent anti-myeloma immune response against transplanted Vk*MYC MM cells was mediated both by NK and CD8⁺ T cells through perforin and IFN-γ pathways. Moreover, CD226 expression was required for optimal antimyeloma efficacy of cyclophosphamide (CTX) and bortezomib (Btz), which are both standardly used to manage MM in patients. Activation of costimulatory receptor CD137 with mAb (4-1BB) exerted strong antimyeloma activity, while inhibition of coinhibitory receptors PD-1 and CTLA-4 had no effect. Taken together, the results of this study provide in vivo evidence that CD226 is important for MM immunosurveillance and indicate that specific immune components should be targeted for optimal MM treatment efficacy. As progressive immunosuppression associates with MM development, strategies aimed to increase immune functions may have important therapeutic implications in MM.

Authors

Camille Guillerey, Lucas Ferrari de Andrade, Slavica Vuckovic, Kim Miles, Shin Foong Ngiow, Michelle C.R. Yong, Michele W.L. Teng, Marco Colonna, David S. Ritchie, Martha Chesi, P. Leif Bergsagel, Geoffrey R. Hill, Mark J. S­myth, Ludovic Martinet

Telomerase regulates MYC-driven oncogenesis independent of its reverse transcriptase activity

• Text
• PDF

Abstract

Constitutively active MYC and reactivated telomerase often coexist in cancers. While reactivation of telomerase is thought to be essential for replicative immortality, MYC, in conjunction with cofactors, confers several growth advantages to cancer cells. It is known that the reactivation of TERT, the catalytic subunit of telomerase, is limiting for reconstituting telomerase activity in tumors. However, while reactivation of TERT has been functionally linked to the acquisition of several “hallmarks of cancer” in tumors, the molecular mechanisms by which this occurs and whether these mechanisms are distinct from the role of telomerase on telomeres is not clear. Here, we demonstrated that first-generation TERT-null mice, unlike Terc-null mice, show delayed onset of MYC-induced lymphomagenesis. We further determined that TERT is a regulator of MYC stability in cancer. TERT stabilized MYC levels on chromatin, contributing to either activation or repression of its target genes. TERT regulated MYC ubiquitination and proteasomal degradation, and this effect of TERT was independent of its reverse transcriptase activity and role in telomere elongation. Based on these data, we conclude that reactivation of TERT, a direct transcriptional MYC target in tumors, provides a feed-forward mechanism to potentiate MYC-dependent oncogenesis.

Authors

Cheryl M. Koh, Ekta Khattar, Shi Chi Leow, Chia Yi Liu, Julius Muller, Wei Xia Ang, Yinghui Li, Guido Franzoso, Shang Li, Ernesto Guccione, Vinay Tergaonkar

Estrogen regulates Hippo signaling via GPER in breast cancer

• Text
• PDF

Abstract

The G protein–coupled estrogen receptor (GPER) mediates both the genomic and nongenomic effects of estrogen and has been implicated in breast cancer development. Here, we compared GPER expression in cancerous tissue and adjacent normal tissue in patients with invasive ductal carcinoma (IDC) of the breast and determined that GPER is highly upregulated in cancerous cells. Additionally, our studies revealed that GPER stimulation activates yes-associated protein 1 (YAP) and transcriptional coactivator with a PDZ-binding domain (TAZ), 2 homologous transcription coactivators and key effectors of the Hippo tumor suppressor pathway, via the Gαq-11, PLCβ/PKC, and Rho/ROCK signaling pathways. TAZ was required for GPER-induced gene transcription, breast cancer cell proliferation and migration, and tumor growth. Moreover, TAZ expression positively correlated with GPER expression in human IDC specimens. Together, our results suggest that the Hippo/YAP/TAZ pathway is a key downstream signaling branch of GPER and plays a critical role in breast tumorigenesis.

Authors

Xin Zhou, Shuyang Wang, Zhen Wang, Xu Feng, Peng Liu, Xian-Bo Lv, Fulong Li, Fa-Xing Yu, Yiping Sun, Haixin Yuan, Hongguang Zhu, Yue Xiong, Qun-Ying Lei, Kun-Liang Guan

Pharmacological HIF2α inhibition improves VHL disease–associated phenotypes in zebrafish model

• Text
• PDF

Abstract

Patients with a germline mutation in von Hippel-Lindau (VHL) develop renal cell cancers and hypervascular tumors of the brain, adrenal glands, and pancreas as well as erythrocytosis. These phenotypes are driven by aberrant expression of HIF2α, which induces expression of genes involved in cell proliferation, angiogenesis, and red blood cell production. Currently, there are no effective treatments available for VHL disease. Here, using an animal model of VHL, we report a marked improvement of VHL-associated phenotypes following treatment with HIF2α inhibitors. Inactivation of vhl in zebrafish led to constitutive activation of HIF2α orthologs and modeled several aspects of the human disease, including erythrocytosis, pathologic angiogenesis in the brain and retina, and aberrant kidney and liver proliferation. Treatment of vhl^–/– mutant embryos with HIF2α-specific inhibitors downregulated Hif target gene expression in a dose-dependent manner, improved abnormal hematopoiesis, and substantially suppressed erythrocytosis and angiogenic sprouting. Moreover, pharmacologic inhibition of HIF2α reversed the compromised cardiac contractility of vhl^–/– embryos and partially rescued early lethality. This study demonstrates that small-molecule targeting of HIF2α improves VHL-related phenotypes in a vertebrate animal model and supports further exploration of this strategy for treating VHL disease.

Authors

Ana Martins Metelo, Haley R. Noonan, Li Xiang, Youngnam Jin, Rania Baker, Lee Kamentsky, Yiyun Zhang, Ellen van Rooijen, Jordan Shin, Anne E. Carpenter, Jing-Ruey Yeh, Randall T. Peterson, Othon Iliopoulos

TIGIT and PD-1 impair tumor antigen–specific CD8⁺ T cells in melanoma patients

• Text
• PDF

Abstract

T cell Ig and ITIM domain (TIGIT) is an inhibitory receptor expressed by activated T cells, Tregs, and NK cells. Here, we determined that TIGIT is upregulated on tumor antigen–specific (TA-specific) CD8⁺ T cells and CD8⁺ tumor-infiltrating lymphocytes (TILs) from patients with melanoma, and these TIGIT-expressing CD8⁺ T cells often coexpress the inhibitory receptor PD-1. Moreover, CD8⁺ TILs from patients exhibited downregulation of the costimulatory molecule CD226, which competes with TIGIT for the same ligand, supporting a TIGIT/CD226 imbalance in metastatic melanoma. TIGIT marked early T cell activation and was further upregulated by T cells upon PD-1 blockade and in dysfunctional PD-1⁺TIM-3⁺ TA-specific CD8⁺ T cells. PD-1⁺TIGIT⁺, PD-1^–TIGIT⁺, and PD-1⁺TIGIT^– CD8⁺ TILs had similar functional capacities ex vivo, suggesting that TIGIT alone, or together with PD-1, is not indicative of T cell dysfunction. However, in the presence of TIGIT ligand–expressing cells, TIGIT and PD-1 blockade additively increased proliferation, cytokine production, and degranulation of both TA-specific CD8⁺ T cells and CD8⁺ TILs. Collectively, our results show that TIGIT and PD-1 regulate the expansion and function of TA-specific CD8⁺ T cells and CD8⁺ TILs in melanoma patients and suggest that dual TIGIT and PD-1 blockade should be further explored to elicit potent antitumor CD8⁺ T cell responses in patients with advanced melanoma.

Authors

Joe-Marc Chauvin, Ornella Pagliano, Julien Fourcade, Zhaojun Sun, Hong Wang, Cindy Sander, John M. Kirkwood, Tseng-hui Timothy Chen, Mark Maurer, Alan J. Korman, Hassane M. Zarour

An epigenetically distinct breast cancer cell subpopulation promotes collective invasion

• Text
• PDF

Abstract

Tumor cells can engage in a process called collective invasion, in which cohesive groups of cells invade through interstitial tissue. Here, we identified an epigenetically distinct subpopulation of breast tumor cells that have an enhanced capacity to collectively invade. Analysis of spheroid invasion in an organotypic culture system revealed that these “trailblazer” cells are capable of initiating collective invasion and promote non-trailblazer cell invasion, indicating a commensal relationship among subpopulations within heterogenous tumors. Canonical mesenchymal markers were not sufficient to distinguish trailblazer cells from non-trailblazer cells, suggesting that defining the molecular underpinnings of the trailblazer phenotype could reveal collective invasion-specific mechanisms. Functional analysis determined that DOCK10, ITGA11, DAB2, PDFGRA, VASN, PPAP2B, and LPAR1 are highly expressed in trailblazer cells and required to initiate collective invasion, with DOCK10 essential for metastasis. In patients with triple-negative breast cancer, expression of these 7 genes correlated with poor outcome. Together, our results indicate that spontaneous conversion of the epigenetic state in a subpopulation of cells can promote a transition from in situ to invasive growth through induction of a cooperative form of collective invasion and suggest that therapeutic inhibition of trailblazer cell invasion may help prevent metastasis.

Authors

Jill M. Westcott, Amanda M. Prechtl, Erin A. Maine, Tuyen T. Dang, Matthew A. Esparza, Han Sun, Yunyun Zhou, Yang Xie, Gray W. Pearson

Specific molecular signatures predict decitabine response in chronic myelomonocytic leukemia

• Text
• PDF

Abstract

Myelodysplastic syndromes and chronic myelomonocytic leukemia (CMML) are characterized by mutations in genes encoding epigenetic modifiers and aberrant DNA methylation. DNA methyltransferase inhibitors (DMTis) are used to treat these disorders, but response is highly variable, with few means to predict which patients will benefit. Here, we examined baseline differences in mutations, DNA methylation, and gene expression in 40 CMML patients who were responsive or resistant to decitabine (DAC) in order to develop a molecular means of predicting response at diagnosis. While somatic mutations did not differentiate responders from nonresponders, we identified 167 differentially methylated regions (DMRs) of DNA at baseline that distinguished responders from nonresponders using next-generation sequencing. These DMRs were primarily localized to nonpromoter regions and overlapped with distal regulatory enhancers. Using the methylation profiles, we developed an epigenetic classifier that accurately predicted DAC response at the time of diagnosis. Transcriptional analysis revealed differences in gene expression at diagnosis between responders and nonresponders. In responders, the upregulated genes included those that are associated with the cell cycle, potentially contributing to effective DAC incorporation. Treatment with CXCL4 and CXCL7, which were overexpressed in nonresponders, blocked DAC effects in isolated normal CD34⁺ and primary CMML cells, suggesting that their upregulation contributes to primary DAC resistance.

Authors

Kristen Meldi, Tingting Qin, Francesca Buchi, Nathalie Droin, Jason Sotzen, Jean-Baptiste Micol, Dorothée Selimoglu-Buet, Erico Masala, Bernardino Allione, Daniela Gioia, Antonella Poloni, Monia Lunghi, Eric Solary, Omar Abdel-Wahab, Valeria Santini, Maria E. Figueroa

MEL-18 loss mediates estrogen receptor–α downregulation and hormone independence

• Text
• PDF

Abstract

The polycomb protein MEL-18 has been proposed as a tumor suppressor in breast cancer; however, its functional relevance to the hormonal regulation of breast cancer remains unknown. Here, we demonstrated that MEL-18 loss contributes to the hormone-independent phenotype of breast cancer by modulating hormone receptor expression. In multiple breast cancer cohorts, MEL-18 was markedly downregulated in triple-negative breast cancer (TNBC). MEL-18 expression positively correlated with the expression of luminal markers, including estrogen receptor–α (ER-α, encoded by ESR1). MEL-18 loss was also associated with poor response to antihormonal therapy in ER-α–positive breast cancer. Furthermore, whereas MEL-18 loss in luminal breast cancer cells resulted in the downregulation of expression and activity of ER-α and the progesterone receptor (PR), MEL-18 overexpression restored ER-α expression in TNBC. Consistently, in vivo xenograft experiments demonstrated that MEL-18 loss induces estrogen-independent growth and tamoxifen resistance in luminal breast cancer, and that MEL-18 overexpression confers tamoxifen sensitivity in TNBC. MEL-18 suppressed SUMOylation of the ESR1 transactivators p53 and SP1, thereby driving ESR1 transcription. MEL-18 facilitated the deSUMOylation process by inhibiting BMI-1/RING1B-mediated ubiquitin-proteasomal degradation of SUMO1/sentrin-specific protease 1 (SENP1). These findings demonstrate that MEL-18 is a SUMO-dependent regulator of hormone receptors and suggest MEL-18 expression as a marker for determining the antihormonal therapy response in patients with breast cancer.

Authors

Jeong-Yeon Lee, Hee-Young Won, Ji-Hye Park, Hye-Yeon Kim, Hee-Joo Choi, Dong-Hui Shin, Ju-Hee Kang, Jong-Kyu Woo, Seung-Hyun Oh, Taekwon Son, Jin-Woo Choi, Sehwan Kim, Hyung-Yong Kim, Kijong Yi, Ki-Seok Jang, Young-Ha Oh, Gu Kong

Noninvasive detection of tumor-infiltrating T cells by PET reporter imaging

• Text
• PDF

Abstract

Adoptive transfer of tumor-reactive T cells can successfully reduce tumor burden; however, in rare cases, lethal on-target/off-tumor effects have been reported. A noninvasive method to track engineered cells with high sensitivity and resolution would allow observation of correct cell homing and/or identification of dangerous off-target locations in preclinical and clinical applications. Human deoxycytidine kinase triple mutant (hdCK3mut) is a nonimmunogenic PET reporter that was previously shown to be an effective tool to monitor whole-body hematopoiesis. Here, we engineered a construct in which hdCK3mut is coexpressed with the anti-melanoma T cell receptor F5, introduced this construct into human CD34 cells or PBMCs, and evaluated this approach in multiple immunotherapy models. Expression of hdCK3mut allowed engrafted cells to be visualized within recipient bone marrow, while accumulation of [¹⁸F]-L-FMAU in hdCK3mut-expressing T cells permitted detection of intratumoral homing. Animals that received T cells coexpressing hdCK3mut and the anti-melanoma T cell receptor had demonstrably higher signals in HLA-matched tumors compared with those in animals that received cells solely expressing hdCK3mut. Engineered T cells caused cytotoxicity in HLA/antigen-matched tumors and induced IFN-γ production and activation. Moreover, hdCK3mut permitted simultaneous monitoring of engraftment and tumor infiltration, without affecting T cell function. Our findings suggest that hdCK3mut reporter imaging can be applied in clinical immunotherapies for whole-body detection of engineered cell locations.

Authors

Melissa N. McCracken, Dimitrios N. Vatakis, Dhaval Dixit, Jami McLaughlin, Jerome A. Zack, Owen N. Witte