Oncologies
Abstract
A prerequisite for strong adaptive antiviral immunity is the robust initial activation of the innate immune system, which is frequently mediated by TLR-activated plasmacytoid DCs (pDCs). Natural antitumor immunity is often comparatively weak, potentially due to the lack of TLR-mediated activation signals within the tumor microenvironment. To assess whether pDCs are capable of directly facilitating effective antitumor immune responses, mice bearing established subcutaneous B16 melanoma tumors were administered TLR9-activated pDCs directly into the tumor. We found that TLR9-activated pDCs induced robust, spontaneous CTL cross-priming against multiple B16 tumor antigens, leading to the regression of both treated tumors and untreated tumors at distant contralateral sites. This T cell cross-priming was mediated by conventional DCs (cDCs) and was completely dependent upon the early recruitment and activation of NK cells at the tumor site. NK cell recruitment was mediated by CCR5 via chemokines secreted by pDCs, and optimal IFN-γ production by NK cells was mediated by OX40L expressed by pDCs. Our data thus demonstrated that activated pDCs are capable of initiating effective and systemic antitumor immunity through the orchestration of an immune cascade involving the sequential activation of NK cells, cDCs, and CD8+ T cells.
Authors
Chengwen Liu, Yanyan Lou, Gregory Lizée, Hong Qin, Shujuan Liu, Brian Rabinovich, Grace J. Kim, Yi-Hong Wang, Yang Ye, Andrew G. Sikora, Willem W. Overwijk, Yong-Jun Liu, Gang Wang, Patrick Hwu
Abstract
Invariant NKT (iNKT) cells are potent activators of DCs, NK cells, and T cells, and their antitumor activity has been well demonstrated. A single injection of the high-affinity CD1d ligand α-galactosylceramide (αGalCer) leads to short-lived iNKT cell activation followed, however, by long-term anergy, limiting its therapeutic use. In contrast, we demonstrated here that when αGalCer was loaded on a recombinant soluble CD1d molecule (αGalCer/sCD1d), repeated injections led to sustained iNKT and NK cell activation associated with IFN-γ secretion as well as DC maturation in mice. Most importantly, when αGalCer/sCD1d was fused to a HER2-specific scFv antibody fragment, potent inhibition of experimental lung metastasis and established s.c. tumors was obtained when systemic treatment was started 2–7 days after the injection of HER2-expressing B16 melanoma cells. In contrast, administration of free αGalCer at this time had no effect. The antitumor activity of the CD1d–anti-HER2 fusion protein was associated with HER2-specific tumor localization and accumulation of iNKT, NK, and T cells at the tumor site. Targeting iNKT cells to the tumor site thus may activate a combined innate and adaptive immune response that may prove to be effective in cancer immunotherapy.
Authors
Kathrin Stirnemann, Jackeline F. Romero, Lucia Baldi, Bruno Robert, Valérie Cesson, Gurdyal S. Besra, Maurice Zauderer, Florian Wurm, Giampietro Corradin, Jean-Pierre Mach, H. Robson MacDonald, Alena Donda
Abstract
The aryl hydrocarbon receptor repressor (AHRR) is a bHLH/Per-ARNT-Sim transcription factor located in a region of chromosome 5 (5p15.3) that has been proposed to contain one or more tumor suppressor genes. We report here consistent downregulation of AHRR mRNA in human malignant tissue from different anatomical origins, including colon, breast, lung, stomach, cervix, and ovary, and demonstrate DNA hypermethylation as the regulatory mechanism of AHRR gene silencing. Knockdown of AHRR gene expression in a human lung cancer cell line using siRNA significantly enhanced in vitro anchorage-dependent and -independent cell growth as well as cell growth after transplantation into immunocompromised mice. In addition, knockdown of AHRR in non-clonable normal human mammary epithelial cells enabled them to grow in an anchorage-independent manner. Further, downregulation of AHRR expression in the human lung cancer cell line conferred resistance to apoptotic signals and enhanced motility and invasion in vitro and angiogenic potential in vivo. Ectopic expression of AHRR in tumor cells resulted in diminished anchorage-dependent and -independent cell growth and reduced angiogenic potential. These results therefore demonstrate that AHRR is a putative new tumor suppressor gene in multiple types of human cancers.
Authors
Enrique Zudaire, Natalia Cuesta, Vundavalli Murty, Karen Woodson, Lisa Adams, Nieves Gonzalez, Alfredo Martínez, Gopeshwar Narayan, Ilan Kirsch, Wilbur Franklin, Fred Hirsch, Michael Birrer, Frank Cuttitta
Abstract
Loss of the tumor suppressor gene von Hippel–Lindau (VHL) plays a key role in the oncogenesis of clear cell renal cell carcinoma (CCRCC). The loss leads to stabilization of the HIF transcription complex, which induces angiogenic and mitogenic pathways essential for tumor formation. Nonetheless, additional oncogenic events have been postulated to be required for the formation of CCRCC tumors. Here, we show that the Notch signaling cascade is constitutively active in human CCRCC cell lines independently of the VHL/HIF pathway. Blocking Notch signaling resulted in attenuation of proliferation and restrained anchorage-independent growth of CCRCC cell lines. Using siRNA targeting the different Notch receptors established that the growth-promoting effects of the Notch signaling pathway were attributable to Notch-1 and that Notch-1 knockdown was accompanied by elevated levels of the negative cell-cycle regulators p21Cip1 and/or p27Kip1. Treatment of nude mice with an inhibitor of Notch signaling potently inhibited growth of xenotransplanted CCRCC cells. Moreover, Notch-1 and the Notch ligand Jagged-1 were expressed at significantly higher levels in CCRCC tumors than in normal human renal tissue, and the growth of primary CCRCC cells was attenuated upon inhibition of Notch signaling. These findings indicate that the Notch cascade may represent a novel and therapeutically accessible pathway in CCRCC.
Authors
Jonas Sjölund, Martin Johansson, Sugata Manna, Carl Norin, Alexander Pietras, Siv Beckman, Elise Nilsson, Börje Ljungberg, Håkan Axelson
Abstract
Overexpression of the receptor tyrosine kinase EPH receptor A2 (EphA2) is commonly observed in aggressive breast cancer and correlates with a poor prognosis. However, while EphA2 has been reported to enhance tumorigenesis, proliferation, and MAPK activation in several model systems, other studies suggest that EphA2 activation diminishes these processes and inhibits the activity of MAPK upon ligand stimulation. In this study, we eliminated EphA2 expression in 2 transgenic mouse models of mammary carcinoma. EphA2 deficiency impaired tumor initiation and metastatic progression in mice overexpressing ErbB2 (also known as Neu) in the mammary epithelium (MMTV-Neu mice), but not in mice overexpressing the polyomavirus middle T antigen in mammary epithelium (MMTV–PyV-mT mice). Histologic and ex vivo analyses of MMTV-Neu mouse mammary epithelium indicated that EphA2 enhanced tumor proliferation and motility. Biochemical analyses revealed that EphA2 formed a complex with ErbB2 in human and murine breast carcinoma cells, resulting in enhanced activation of Ras-MAPK signaling and RhoA GTPase. Additionally, MMTV-Neu, but not MMTV–PyV-mT, tumors were sensitive to therapeutic inhibition of EphA2. These data suggest that EphA2 cooperates with ErbB2 to promote tumor progression in mice and may provide a novel therapeutic target for ErbB2-dependent tumors in humans. Moreover, EphA2 function in tumor progression appeared to depend on oncogene context, an important consideration for the application of therapies targeting EphA2.
Authors
Dana M. Brantley-Sieders, Guanglei Zhuang, Donna Hicks, Wei Bin Fang, Yoonha Hwang, Justin M.M. Cates, Karen Coffman, Dowdy Jackson, Elizabeth Bruckheimer, Rebecca S. Muraoka-Cook, Jin Chen
Abstract
Cells isolated from many types of human cancers express heparin-binding growth factors (HBGFs) that drive tumor growth, metastasis, and angiogenesis. The heparan sulfate proteoglycan glypican-1 (GPC1) is a coreceptor for HBGFs. Here we show that both cancer cell–derived and host-derived GPC1 are crucial for efficient growth, metastasis, and angiogenesis of human and mouse cancer cells. Thus downregulation of GPC1 in the human pancreatic cancer cell line PANC-1, using antisense approaches, resulted in prolonged doubling times and decreased anchorage-independent growth in vitro as well as attenuated tumor growth, angiogenesis, and metastasis when these cells were transplanted into athymic mice. Moreover, athymic mice that lacked GPC1 exhibited decreased tumor angiogenesis and metastasis following intrapancreatic implantation with either PANC-1 or T3M4 human pancreatic cancer cells and fewer pulmonary metastases following intravenous injection of murine B16-F10 melanoma cells. In addition, hepatic endothelial cells isolated from these mice exhibited an attenuated mitogenic response to VEGF-A. These data indicate that cancer cell– and host-derived GPC1 are crucial for full mitogenic, angiogenic, and metastatic potential of cancer cells. Thus targeting GPC1 might provide new avenues for cancer therapy and for the prevention of cancer metastasis.
Authors
Takuma Aikawa, Chery A. Whipple, Martha E. Lopez, Jason Gunn, Alison Young, Arthur D. Lander, Murray Korc
Abstract
Survival of patients with B cell chronic lymphocytic leukemia (B-CLL) can be predicted by analysis of mutations in the immunoglobulin heavy chain variable gene (IGHV). Patients without mutations (unmutated [UM]) are at greater risk for disease progression and death than patients with mutations (M). Despite this broad prognostic difference, there remains wide intragroup variation in the clinical outcome of UM patients, especially those with low/intermediate Rai risk disease. We evaluated UM B-CLL patients with low/intermediate Rai risk to determine the relationship between IGHV, IGH diversity (IGHD), and IGH joining (IGHJ) gene usage and time to treatment (TTT). Irrespective of IGHV usage, UM patients whose B-CLL cells expressed the IGHD3-3 gene had a significantly shorter TTT than other UM B-CLL patients, and specifically, use of the IGHD3-3 gene in reading frame 2 (RF2) predicted shorter TTT. As expected, Rai risk was the best single prognostic factor for TTT; however, IGHD usage was also a significant variable for TTT. Therefore, both IGHD gene and IGHD RF usage have prognostic relevance in UM B-CLL patients with low/intermediate Rai risk disease. In addition, these data support the concept that antigen-driven selection of specific Ig receptors plays a role in the clinical course of B-CLL.
Authors
Renee C. Tschumper, Susan M. Geyer, Megan E. Campbell, Neil E. Kay, Tait D. Shanafelt, Clive S. Zent, Grzegorz S. Nowakowski, Timothy G. Call, Gordon W. Dewald, Diane F. Jelinek
Abstract
The proprotein convertases (PCs) are implicated in the activation of various precursor proteins that play an important role in tumor cell metastasis. Here, we report their involvement in the regulation of the metastatic potential of colorectal tumor cells. PC function in the human and murine colon carcinoma cell lines HT-29 and CT-26, respectively, was inhibited using siRNA targeting the PCs furin, PACE4, PC5, and PC7 or by overexpression of the general PC inhibitor α1-antitrypsin Portland (α1-PDX). We found that overexpression of α1-PDX and knockdown of furin expression inhibited processing of IGF-1 receptor and its subsequent activation by IGF-1 to induce IRS-1 and Akt phosphorylation, all important in colon carcinoma metastasis. These data suggest that the PC furin is a major IGF-1 receptor convertase. Expression of α1-PDX reduced the production of TNF-α and IL-1α by human colon carcinoma cells, and incubation of murine liver endothelial cells with conditioned media derived from these cells failed to induce tumor cell adhesion to activated murine endothelial cells, a critical step in metastatic invasion. Furthermore, colon carcinoma cells in which PC activity was inhibited by overexpression of α1-PDX when injected into the portal vein of mice showed a significantly reduced ability to form liver metastases. This suggests that inhibition of PCs is a potentially promising strategy for the prevention of colorectal liver metastasis.
Authors
Nathalie Scamuffa, Geraldine Siegfried, Yannick Bontemps, Liming Ma, Ajoy Basak, Ghislaine Cherel, Fabien Calvo, Nabil G. Seidah, Abdel-Majid Khatib
Abstract
The vast majority of primary human breast cancer tissues display aberrant nuclear NF-κB c-Rel expression. A causal role for c-Rel in mammary tumorigenesis has been demonstrated using a c-Rel transgenic mouse model; however, tumors developed with a long latency, suggesting a second event is needed to trigger tumorigenesis. Here we show that c-Rel activity in the mammary gland is repressed by estrogen receptor α (ERα) signaling, and we identify an epigenetic mechanism in breast cancer mediated by activation of what we believe is a novel PKCθ-Akt pathway that leads to downregulation of ERα synthesis and derepression of c-Rel. ERα levels were lower in c-Rel–induced mammary tumors compared with normal mammary gland tissue. PKCθ induced c-Rel activity and target gene expression and promoted growth of c-Rel- and c-RelxCK2α–driven mouse mammary tumor–derived cell lines. RNA expression levels of PKCθ and c-Rel target genes were inversely correlated with ERα levels in human breast cancer specimens. PKCθ activated Akt, thereby inactivating forkhead box O protein 3a (FOXO3a) and leading to decreased synthesis of its target genes, ERα and p27Kip1. Thus we have shown that activation of PKCθ inhibits the FOXO3a/ERα/p27Kip1 axis that normally maintains an epithelial cell phenotype and induces c-Rel target genes, thereby promoting proliferation, survival, and more invasive breast cancer.
Authors
Karine Belguise, Gail E. Sonenshein
Abstract
Breast cancers frequently progress or relapse during targeted therapy, but the molecular mechanisms that enable escape remain poorly understood. We elucidated genetic determinants underlying tumor escape in a transgenic mouse model of Wnt pathway–driven breast cancer, wherein targeted therapy is simulated by abrogating doxycycline-dependent Wnt1 transgene expression within established tumors. In mice with intact tumor suppressor pathways, tumors typically circumvented doxycycline withdrawal by reactivating Wnt signaling, either via aberrant (doxycycline-independent) Wnt1 transgene expression or via acquired somatic mutations in the gene encoding β-catenin. Germline introduction of mutant tumor suppressor alleles into the model altered the timing and mode of tumor escape. Relapses occurring in the context of null Ink4a/Arf alleles (disrupting both the p16Ink4a and p19Arf tumor suppressors) arose quickly and rarely reactivated the Wnt pathway. In addition, Ink4a/Arf-deficient relapses resembled p53-deficient relapses in that both displayed morphologic and molecular hallmarks of an epithelial-to-mesenchymal transition (EMT). Notably, Ink4a/Arf deficiency promoted relapse in the absence of gross genomic instability. Moreover, Ink4a/Arf-encoded proteins differed in their capacity to suppress oncogene independence. Isolated p19Arf deficiency mirrored p53 deficiency in that both promoted rapid, EMT-associated mammary tumor escape, whereas isolated p16Ink4a deficiency failed to accelerate relapse. Thus, p19Arf/p53 pathway lesions may promote mammary cancer relapse even when inhibition of a targeted oncogenic signaling pathway remains in force.
Authors
Michael T. Debies, Shelley A. Gestl, Jessica L. Mathers, Oliver R. Mikse, Travis L. Leonard, Susan E. Moody, Lewis A. Chodosh, Robert D. Cardiff, Edward J. Gunther
Copyright © 2023 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)