Cancer Immunology Research

Immune checkpoint blockade using antibodies to cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) benefits a limited number of cancer patients. SS1P and LMB-100 are immunotoxins that target mesothelin. We observed delayed responses to SS1P in patients with mesothelioma suggesting that anti-tumor immunity was induced. Our goal was to stimulate anti-tumor immunity by combining SS1P or LMB-100 with anti-CTLA-4. We constructed a BALB/c breast cancer cell line expressing human mesothelin (66C14-M) which was implanted in one or two locations...

Coordinated manipulation of independent immune regulatory pathways in the tumor microenvironment - including blockade of T-cell checkpoint receptors and reversal of suppressive myeloid programs - can render aggressive cancers susceptible to immune rejection. Elevated toxicity associated with combination immunotherapy, however, prevents translation of the most efficacious regimens. We evaluated T-cell checkpoint modulating antibodies targeting CTLA-4, PD-1, and 4-1BB together with myeloid agonists targeting either STING or Flt3 in the TRAMP-C2 model of prostate cancer to determine whether low-dose intratumoral delivery of these agents could elicit systemic control of multi-focal disease...

The endoplasmic reticulum (ER) is an energy-sensing organelle with intimate ties to programming cell activation and metabolic fate. T-cell receptor (TCR) activation represents a form of acute cell stress and induces mobilization of ER Ca(2+) stores. The role of the ER in programming T-cell activation and metabolic fate remains largely undefined. Gp96 is an ER protein with functions as a molecular chaperone and Ca(2+) buffering protein. We hypothesized that the ER stress response may be important for CD4(+) T-cell activation and that gp96 may be integral to this process...

One of the next challenges in cancer immunotherapy is the resistance of tumors to T cell-based treatments through loss of MHC class I. Here, we show that under these circumstances, the Toll-like receptor (TLR)-7/8 ligand imiquimod, but not the TLR3 ligand poly I:C or TLR9 ligand CpG, mediated an effective antitumor response. The rejection of these immune-escaped cancers was mediated by NK cells and CD4(+) T cells, whereas activated CD8(+) T cells were dispensable. Application of the innate immune stimulator at a distant site activated NK cells and thereby elicited tumor-specific T-cell responses in tumor-bearing mice...

Manipulation of human NK cell repertoires promises more effective strategies for NK cell-based cancer immunotherapy. A subset of highly differentiated NK cells, termed adaptive NK cells, expands naturally in vivo in response to human cytomegalovirus (HCMV) infection, carries unique repertoires of inhibitory killer cell immunoglobulin-like receptors (KIRs), and displays strong cytotoxicity against tumor cells. Here, we established a robust and scalable protocol for ex vivo generation and expansion of adaptive NK cells for cell therapy against pediatric acute lymphoblastic leukemia (ALL)...

Although allogeneic stem cell transplantation (allo-SCT) can elicit graft-versus-tumor (GVT) immunity, patients often relapse due to residual tumor cells. As essential orchestrators of the immune system, vaccination with dendritic cells (DCs) is an appealing strategy to boost the GVT-response. Nevertheless, durable clinical responses after DC vaccination are still limited, stressing the need to improve current DC vaccines. Aiming to empower DC potency, we engineered monocyte-derived DCs to deprive them of ligands for the immune checkpoint regulated by programmed death 1 (PD-1)...

Antitumor vaccines encoding self-antigens generally have low immunogenicity in clinical trials. Several approaches are aimed at improving vaccine immunogenicity, including efforts to alter encoded epitopes. Immunization with epitopes altered for increased affinity for the major histocompatibility complex (MHC) or T-cell receptor (TCR) elicits greater numbers of CD8 T cells but inferior antitumor responses. Our previous results suggested that programmed death 1 (PD-1) and its ligand (PD-L1) increased on antigen-specific CD8 T cells and tumor cells, respectively, after high-affinity vaccination...

Cytotoxic T lymphocyte (CTL)-based immunotherapies have had remarkable success at generating objective clinical responses in patients with advanced metastatic melanoma.  Although the melanocyte differentiation antigens (MDAs) MART-1, PMEL, and tyrosinase were among the first melanoma tumor-associated antigens identified and targeted with immunotherapy, expression within normal melanocytes of the eye and inner ear can elicit serious autoimmune side effects, thus limiting their clinical potential as CTL targets...

Next-generation sequencing technologies have provided insights into the biology and mutational landscape of cancer. Here we evaluate the relevance of cancer neoantigens in human breast cancers. Using patient-derived xenografts from three patients with advanced breast cancer (xenografts were designated as WHIM30, WHIM35, and WHIM37), we sequenced exomes of tumor and patient-matched normal cells. We identified 2091 (WHIM30), 354 (WHIM35), and 235 (WHIM37) nonsynonymous somatic mutations. A computational analysis identified and prioritized HLA class I-restricted candidate neoantigens expressed in the dominant tumor clone...

Colorectal cancer (CRC) results from progressive accumulation of genetic and epigenetic alterations. IFN signaling defects play an important role in the carcinogenesis process, in which the inability of IFN transcription regulatory factors (IRFs) to access regulatory sequences in IFN-stimulated genes (ISGs) in tumors and in immune cells may be pivotal. We reported that low-dose combination of two FDA-approved epidrugs, azacytidine (A) and romidepsin (R), with IFNa2 (ARI) hampers the aggressiveness of both CRC metastatic and stem cells in vivo and triggers immunogenic cell death signals that stimulate dendritic cell (DC) function...

Over 60% of human melanoma tumors bear a mutation in the BRAF gene. The most frequent mutation is a substitution at codon 600 (V600E), leading to a constitutively active BRAF and overactivation of the mitogen-activated protein kinase (MAPK) pathway. Patients harboring mutated BRAF respond to kinase inhibitors such as vemurafenib. However, these responses are transient and relapses are frequent. Melanoma cells are efficiently lysed by activated natural killer (NK) cells. Melanoma cells express several stress-induced ligands that are recognized by activating NK cell receptors...

Glioblastoma (GBM) is the most aggressive primary brain tumor in adults and is virtually incurable with conventional therapies. Immunotherapy with T cells expressing GBM-specific chimeric antigen receptors (CARs) is an attractive approach to improve outcomes. Although CAR T cells targeting GBM antigens such as IL13Ralpha2 (interleukin 13 Receptor Subunit Alpha 2), HER2 (human epidermal growth factor receptor 2), and EGFRvIII (epidermal growth factor receptor variant III) have had antitumor activity in preclinical models, early phase clinical testing has demonstrated limited antiglioma activity...

M2-polarized tumor associated macrophages (TAM) play a critical role in cancer invasion and metastasis. Here, we report that M2 macrophages enhanced metastasis of K7M2 WT osteosarcoma cells to the lung in mice, thus establishing M2 TAMs as a therapeutic target for blocking osteosarcoma metastasis. We found that all-trans retinoic acid (ATRA) inhibited osteosarcoma metastasis via inhibiting the M2 polarization of TAMs. ATRA suppressed IL13 or IL4 induced M2-type macrophages, and then inhibited migration of osteosarcoma cells as promoted by M2-type macrophages in vitro ATRA reduced the number of pulmonary metastatic nodes of osteosarcoma and decreased expression of M2-type macrophages in metastatic nodes both in intravenous injection and orthotopic transplantation models...

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The American Joint Committee on Cancer (AJCC) staging system is insufficiently prognostic for operable gastric cancer patients; therefore, complementary factors are under intense investigation. Although the focus is on immune markers, the prognostic impact of a single immune factor is minimal, due to complex antitumor immune responses. A more comprehensive evaluation may engender more accurate predictions. We analyzed immune factors by immunohistochemical staining in two independent cohorts. The association with patients' survival was analyzed by the Kaplan-Meier method...

Intravesical bacillus Calmette-Guérin (BCG) immunotherapy is the standard of care in treating non-muscle-invasive bladder cancer, yet its mechanism of action remains elusive. Both innate and adaptive immune responses have been implicated in BCG activity. Although prior research has indirectly demonstrated the importance of T cells and shown a rise in CD4(+) T cells in bladder tissue after BCG, T-cell subpopulations have not been fully characterized. We investigated the relationship between effector and regulatory T cells in an immune competent, clinically relevant rodent model of bladder cancer...

New immunotherapeutic strategies are needed to induce effective antitumor immunity in all cancer patients. Malignant mesothelioma is characterized by a poor prognosis and resistance to conventional therapies. Infiltration of tumor-associated macrophages (TAM) is prominent in mesothelioma and is linked to immune suppression, angiogenesis, and tumor aggressiveness. Therefore, TAM depletion could potentially reactivate antitumor immunity. We show that M-CSFR inhibition using the CSF-1R kinase inhibitor PLX3397 (pexidartinib) effectively reduced numbers of TAMs, circulating nonclassical monocytes, as well as amount of neoangiogenesis and ascites in mesothelioma mouse models, but did not improve survival...

Anti-hCD20 is a therapeutic mAb that is clinically used to treat B-cell lymphoma. Some lymphomas are resistant to anti-hCD20; others relapse after treatment with anti-hCD20. Using a syngeneic immunocompetent mouse model, we observed that targeting lymphoma with interferon-α (IFNα) abolished resistance of B-cell lymphoma to anti-CD20 while limiting interferon (IFN)-associated systemic toxicity in the host. Control of tumors by a fusion of anti-CD20 and IFNα (anti-CD20-IFNα) depended on existing tumor-infiltrating CD8(+) T cells...

The Keystone Symposia conference on Cancer Immunology and Immunotherapy: Taking a Place in Mainstream Oncology was held at the Fairmont Chateau in Whistler, British Columbia, Canada, on March 19-23, 2017. The conference brought together a sold-out audience of 654 scientists, clinicians, and others from both academia and industry to discuss the latest developments in cancer immunology and immunotherapy. This meeting report summarizes the main themes that emerged during the four-day conference. Cancer Immunol Res; 5(6); 434-8...

Adaptive evolution has prompted immune cells to use a wide variety of inhibitory signals, many of which are usurped by tumor cells to evade immune surveillance. Although tumor immunologists often focus on genes and proteins as mediators of immune function, here we highlight two elements from the periodic table-oxygen and potassium-that suppress the immune system in previously unappreciated ways. While both are key to the maintenance of T-cell function and tissue homeostasis, they are exploited by tumors to suppress immuno-surveillance and promote metastatic spread...