Circular RNA hsa_circ_0001829 promotes gastric cancer progression through miR-155-5p/SMAD2 axis.

BACKGROUND: Accumulating evidences have shown that circular RNAs (circRNAs) play important roles in regulating the pathogenesis of cancer. However, the role of circRNAs in gastric cancer (GC) remains largely unclear. METHODS: In this study, we identified a novel upregulated circRNA, hsa_circ_0001829, in chemically induced malignant transformed human gastric epithelial cells using RNA-seq. Subsequent qRT-PCR and ISH assays were performed to detect the expression level of hsa_circ_0001829 in GC cell lines and tissues. Functional roles of hsa_circ_0001829 in GC were then explored by loss- and gain-of- function assays. Bioinformatic prediction and luciferase assay were used to investigate potential mechanisms of hsa_circ_0001829. Finally, the mice xenograft and metastasis models were constructed to assess the function of hsa_circ_0001829 in vivo. RESULTS: We found that hsa_circ_0001829 was significantly upregulated in GC tissues and cell lines. Loss- and gain-of- function assays showed that hsa_circ_0001829 promotes GC cells proliferation, migration and invasion, and the affected cell cycle progression and apoptosis rates may account for the effect of hsa_circ_0001829 on GC proliferation. In addition, bioinformatic prediction and luciferase assay showed that hsa_circ_0001829 acts as a molecular sponge for miR-155-5p and that SMAD2 was a target gene of miR-155-5p; moreover, hsa_circ_0001829 sponges miR-155-5p to regulate SMAD2 expression and hsa_circ_0001829 promotes GC progression through the miR-155-5p-SMAD2 pathway. Finally, suppression of hsa_circ_0001829 expression inhibited tumor growth and aggressiveness in vivo. CONCLUSION: Taken together, our findings firstly demonstrated a novel oncogenic role of hsa_circ_0001829 in GC progression through miR-155-5p-SMAD2 axis, and our study may offer novel biomarkers and therapeutic targets for GC.

Expression profiles of genes associated with inflammatory responses and oxidative stress in lung after heat stroke.

BACKGROUND: Heat stroke (HS) is a physically dysfunctional illness caused by hyperthermia. Lung, as the important place for gas-exchange and heat-dissipation organ, is often first to be injured. Lung injury caused by HS impairs the ventilation function of lung, which will subsequently cause damage to other tissues and organs. Nevertheless, the specific mechanism of lung injury in heat stroke is still unknown. METHODS: Rat lung tissues from controls or HS models were harvested. The gene expression profile was identified by high-throughput sequencing. DEGs were calculated using R and validated by qRT-PCR. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and cell-enrichment were performed using differential expression genes (DEGs). Finally, lung histopathology was accessed by H&E staining. RESULTS: About 471 genes were identified to be DEGs, of which 257 genes were up-regulated, and 214 genes were down-regulated. The most up-regulated and down-regulated DEGs were validated by qRT-PCR, which confirmed the tendency of expression. GO, KEGG, and protein-protein interaction (PPI)-network analyses disclosed DEGs were significantly enriched in leukocyte migration, response to lipopolysaccharide, NIK/NF-kappaB signaling, response to reactive oxygen species, response to heat, and the hub genes were Tnf, Il1b, Cxcl2, Ccl2, Mmp9, Timp1, Hmox1, Serpine1, Mmp8 and Csf1, most of which were closely related to inflammagenesis and oxidative stress. Finally, cell-enrichment analysis and histopathologic analysis showed Monocytes, Megakaryotyes, and Macrophages were enriched in response to heat stress. CONCLUSIONS: The present study identified key genes, signal pathways and infiltrated-cell types in lung after heat stress, which will deepen our understanding of transcriptional response to heat stress, and might provide new ideas for the treatment of HS.

Targeting cancers through TCR-peptide/MHC interactions.

Adoptive T cell therapy has achieved dramatic success in a clinic, and the Food and Drug Administration approved two chimeric antigen receptor-engineered T cell (CAR-T) therapies that target hematological cancers in 2018. A significant issue faced by CAR-T therapies is the lack of tumor-specific biomarkers on the surfaces of solid tumor cells, which hampers the application of CAR-T therapies to solid tumors. Intracellular tumor-related antigens can be presented as peptides in the major histocompatibility complex (MHC) on the cell surface, which interact with the T cell receptors (TCR) on antigen-specific T cells to stimulate an anti-tumor response. Multiple immunotherapy strategies have been developed to eradicate tumor cells through targeting the TCR-peptide/MHC interactions. Here, we summarize the current status of TCR-based immunotherapy strategies, with particular focus on the TCR structure, activated signaling pathways, the effects and toxicity associated with TCR-based therapies in clinical trials, preclinical studies examining immune-mobilizing monoclonal TCRs against cancer (ImmTACs), and TCR-fusion molecules. We propose several TCR-based therapeutic strategies to achieve optimal clinical responses without the induction of autoimmune diseases.

Intraoperative Chemotherapy with a Novel Regimen Improved the Therapeutic Outcomes of Colorectal Cancer.

Background: This study sought to evaluate the efficacy of a novel intraoperative chemotherapy (IOC) regimen that consists of hydroxycamptothecin, tumor necrosis factor (TNF), 5-fluorouracil (5-FU), and calcium folinate (CF) on the outcomes of colorectal cancer (CRC). Methods: In total, 551 CRC patients who had undergone surgical resection were evaluated. Among these patients, 247 were treated with postoperative adjuvant chemotherapy, and 193 were treated with intraoperative chemotherapy. Of the CRC patients who underwent chemotherapy, 52 were treated with both postoperative adjuvant chemotherapy and intraoperative chemotherapy. Patients' characteristics, including age, sex, stage, differentiation, lymph node metastasis, surgical-pathological staging, tumor location, tumor size, and relapse-free survival, were collected. Results: IOC for CRC therapy was associated with a more favorable survival prognosis (HR, 0.30, 95%CI, 0.19-0.48, P<0.001) independent of other clinical covariates. CRC patients treated with IOC survived longer than patients who were not treated with IOC did during surgery (P<0.0001, Kaplan-Meier log rank). Meanwhile, a Kaplan-Meier analysis demonstrated that individuals who received both IOC and POC survived longer than patients who received only POC: for stage II and stage III patients (P=0.0001, Kaplan-Meier log rank), stage II patients alone (P=0.02, Kaplan-Meier log rank), and stage III patients alone (P=0.046, Kaplan-Meier log rank). Conclusions: The therapeutic effects of colorectal cancer by intraoperative chemotherapy with a novel regimen were enhanced, which improved the prognosis of patients with CRC.

TCR-like antibodies in cancer immunotherapy.

Cancer immunotherapy has been regarded as the most significant scientific breakthrough of 2013, and antibody therapy is at the core of this breakthrough. Despite significant success achieved in recent years, it is still difficult to target intracellular antigens of tumor cells with traditional antibodies, and novel therapeutic strategies are needed. T cell receptor (TCR)-like antibodies comprise a novel family of antibodies that can recognize peptide/MHC complexes on tumor cell surfaces. TCR-like antibodies can execute specific and significant anti-tumor immunity through several distinct molecular mechanisms, and the success of this type of antibody therapy in melanoma, leukemia, and breast, colon, and prostate tumor models has excited researchers in the immunotherapy field. Here, we summarize the generation strategy, function, and molecular mechanisms of TCR-like antibodies described in publications, focusing on the most significant discoveries.

CXCR5+CD8+ T cells are a distinct functional subset with an antitumor activity.

CXCR5 mediates homing of both B and follicular helper T (TFH) cells into follicles of secondary lymphoid organs. We found that CXCR5+CD8+ T cells are present in human tonsils and follicular lymphoma, inhibit TFH-mediated B cell differentiation, and exhibit strong cytotoxic activity. Consistent with these findings, adoptive transfer of CXCR5+CD8+ T cells into an animal model of lymphoma resulted in significantly greater antitumor activity than CXCR5-CD8+ T cells. Furthermore, RNA-Seq-based transcriptional profiling revealed 77 differentially expressed genes unique to CXCR5+CD8+ T cells. Among these, a signature comprised of 33 upregulated genes correlated with improved survival in follicular lymphoma patients. We also showed that CXCR5+CD8+ T cells could be induced and expanded ex vivo using IL-23 plus TGF-ß, suggesting a possible strategy to generate these cells for clinical application. In summary, our study identified CXCR5+CD8+ T cells as a distinct T cell subset with ability to suppress TFH-mediated B cell differentiation, exert strong antitumor activity, and confer favorable prognosis in follicular lymphoma patients.

MicroRNA-21 increases the expression level of occludin through regulating ROCK1 in prevention of intestinal barrier dysfunction.

OBJECTIVE: The aim of this study is to investigate the role of molecular mechanism of microRNA (miR)-21 on tight junction (TJ)-proteins and its protective effects on the intestinal barrier. METHODS: TJ proteins and target genes expression were analyzed in miR-21 inhibition and overexpression NCM460 cell lines. To further verify the role of miR-21, the mmu-miR-21 intestinal epithelial conditional knockout (IKO) mice model was established. MiR-21 expression was detected in clinical specimens of acute stercoral obstruction patients. RESULTS: Rho-associated protein kinase 1 (ROCK1) were identified as target genes of miR-21. There is a negative correlation between miR-21 expression level and TJ proteins levels. TJ protein and ROCK1 were significantly decreased in miR-21 IKO mice, which presented intestinal inflammation response and intestinal barrier dysfunction (both P < 0.05). Determination of clinical samples showed consistent results with NCM460 cell line and miR-21 IKO mice. CONCLUSIONS: MiR-21 could be a protective factor of intestinal barrier dysfunction, which promoting the expression of TJ protein by targeting ROCK1 in vivo and in vitro.

Identification of surrogate prognostic biomarkers for allergic asthma in nasal epithelial brushing samples by WGCNA.

BACKGROUND: Allergic asthma is a lower respiratory tract disease of Th2 inflammation with multiple molecular mechanisms. The upper and lower airways can be unified by the concept of a united airway and, as such, gene expression studies of upper epithelial cells may provide effective surrogate biomarkers for the prognostic study of allergic asthma. OBJECTIVE: To identify surrogate biomarkers in upper airway epithelial cells for the prognostic study of allergic asthma. METHODS: Nasal epithelial cell gene expression in 40 asthmatic and 17 healthy control subjects were analyzed by weighted gene coexpression network analysis (WGCNA) to identify gene network modules and profiles in allergic asthma. Functional enrichment analysis was performed on the coexpression genes in certain highlighted modules. RESULTS: A total of 13 coexpression modules were constructed by WGCNA from 2804 genes in nasal epithelial brushing samples of the 40 asthmatic and 17 healthy subjects. The number of genes in these modules ranged from 1086 (Turquoise module) to 45 (Salmon). Eight coexpression modules were found to be significantly correlated (P < 0.05) with two clinic traits, namely disease status, and severity. Four modules were positively correlated ( P < 0.05) with the traits and these, therefore, contained genes that are mostly overexpressed in asthma. Contrastingly, the four other modules were found to be negatively correlated with the clinic traits. Functional enrichment analysis of the positively correlated modules showed that one (Magenta) was mainly enriched in mast cell activation and degranulation; another (Pink) was largely involved in immune cell response; the third (Yellow) was predominantly enriched in transmembrane signal pathways; and the last (Blue) was mainly enriched in substructure components of the cells. The hub genes in the modules were KIT, KITLG, GATA2, CD44, PTPRC, and CFTR, and these were confirmed as having significantly higher expression in the nasal epithelial cells. Combining the six hub genes enabled a relatively high capacity for discrimination between asthmatics and healthy subjects with an area under the receiver operating characteristic (ROC) curve of 0.924. CONCLUSIONS: Our findings provide a framework of coexpression gene modules from nasal epithelial brushing samples that could be used for the prognostic study of allergic asthma.

Elevated expression of PTCD3 correlates with tumor progression and predicts poor prognosis in patients with prostate cancer.

Pentatricopeptide repeat domain protein 3 (PTCD3) is a mitochondrial RNA­binding protein that serves a role in mitochondrial translation. PTCD3 was originally reported as an oncogene that is involved in breast cancer and lymphoma. However, the expression and function of PTCD3 in prostate cancer (PCa) are unknown. Therefore, the aim of the present study was to investigate the expression of PTCD3 and its clinical significance in PCa. Immunohistochemistry and dataset analyses revealed that PTCD3 protein expression levels were enhanced in human PCa tissues and mouse PCa models. PTCD3 expression levels were positively correlated with advanced PCa pathological grade and clinical stage. Additionally, PTCD3 mRNA expression was positively correlated with tissue malignancy, high Gleason score and distant metastasis in The Cancer Genome Atlas dataset. Kaplan­Meier analysis revealed that high PTCD3 levels can predict the increased biochemical recurrence (BCR)­free survival in all patients with or without metastasis. The overexpression of PTCD3 could be used as an independent prognostic marker of poor BCR­free survival. Immunofluorescence and western blot analysis in human PCa cell lines further confirmed that PTCD3 levels were associated with the hormone independence of PCa. Therefore, the present study revealed that PTCD3 levels may serve as a novel biomarker for PCa prognosis.

Targeting the Leukemia Antigen PR1 with Immunotherapy for the Treatment of Multiple Myeloma.

Purpose: PR1 is a human leukocyte antigen (HLA)-A2 nonameric peptide derived from neutrophil elastase (NE) and proteinase 3 (P3). We have previously shown that PR1 is cross-presented by solid tumors, leukemia, and antigen-presenting cells, including B cells. We have also shown that cross-presentation of PR1 by solid tumors renders them susceptible to killing by PR1-targeting immunotherapies. As multiple myeloma is derived from B cells, we investigated whether multiple myeloma is also capable of PR1 cross-presentation and subsequently capable of being targeted by using PR1 immunotherapies.Experimental Design: We tested whether multiple myeloma is capable of cross-presenting PR1 and subsequently becomes susceptible to PR1-targeting immunotherapies, using multiple myeloma cell lines, a xenograft mouse model, and primary multiple myeloma patient samples.Results: Here we show that multiple myeloma cells lack endogenous NE and P3, are able to take up exogenous NE and P3, and cross-present PR1 on HLA-A2. Cross-presentation by multiple myeloma utilizes the conventional antigen processing machinery, including the proteasome and Golgi, and is not affected by immunomodulating drugs (IMiD). Following PR1 cross-presentation, we are able to target multiple myeloma with PR1-CTL and anti-PR1/HLA-A2 antibody both in vitro and in vivoConclusions: Collectively, our data demonstrate that PR1 is a novel tumor-associated antigen target in multiple myeloma and that multiple myeloma is susceptible to immunotherapies that target cross-presented antigens. Clin Cancer Res; 24(14); 3386-96. ©2018 AACR.

Targeting B-cell malignancies through human B-cell receptor specific CD4+ T cells.

The B-cell receptor (BCR) expressed by a clonal B cell tumor is a tumor specific antigen (idiotype). However, the T-cell epitopes within human BCRs which stimulate protective immunity still lack detailed characterization. In this study, we identified 17 BCR peptide-specific CD4+ T-cell epitopes derived from BCR heavy and light chain variable region sequences. Detailed analysis revealed these CD4+ T-cell epitopes stimulated normal donors' and patients' Th1 CD4+ T cells to directly recognize the autologous tumors by secretion of IFNγ, indicating the epitopes are processed and presented by tumor cells. One BCR peptide-specific CD4+ T cell line was also cytotoxic and lysed autologous tumor cells through the perforin pathway. Sequence analysis of the epitopes revealed that 10 were shared by multiple primary patients' tumors, and 16 had the capacity to bind to more than one HLA DRB1 allele. T cells stimulated by shared epitopes recognized primary tumors expressing the same sequences on multiple HLA DRB1 alleles. In conclusion, we identified 17 BCR-derived CD4+ T-cell epitopes with promiscuous HLA DRB1 binding affinity that are shared by up to 36% of patients, suggesting a strategy to overcome the requirement for individual preparation of therapeutic agents targeting idiotype.

IL-15 enhances the antitumor effect of human antigen-specific CD8+ T cells by cellular senescence delay.

Optimal expansion protocols for adoptive human T-cell therapy often include interleukin (IL)-15; however, the mechanism by which IL-15 improves the in vivo antitumor effect of T cells remains to be elucidated. Using human T cells generated from HLA-A2+ donors against novel T-cell epitopes derived from the human U266 myeloma cell line Ig light chain V-region (idiotype) as a model, we found that T cells cultured with IL-15 provided superior resistance to tumor growth in vivo, compared with IL-2, after adoptive transfer into immunodeficient hosts. This effect of IL-15 was associated with delayed/reversed senescence in tumor antigen-specific memory CD8+ T cells mediated through downregulation of P21WAF1, P16INK4a, and P53 expression. Compared to IL-2, IL-15 stimulation dramatically activated JAK3-STAT5 signaling and inhibited the expression of DNA damage genes. Thus, our study elucidates a new mechanism for IL-15 in the regulation of STAT signaling pathways and CD8+ T-cell senescence.

Targeting of TLRs inhibits CD4+ regulatory T cell function and activates lymphocytes in human peripheral blood mononuclear cells.

Accumulating evidence suggests elements within tumors induce exhaustion of effector T cells and infiltration of immunosuppressive regulatory T cells (Tregs), thus preventing the development of durable antitumor immunity. Therefore, the discovery of agents that simultaneously block Treg suppressive function and reinvigorate effector function of lymphocytes is key to the development of effective cancer immunotherapy. Previous studies have shown that TLR ligands (TLRLs) could modulate the function of these T cell targets; however, those studies relied on cell-free or accessory cell-based assay systems that do not accurately reflect in vivo responses. In contrast, we used a human PBMC-based proliferation assay system to simultaneously monitor the effect of TLRLs on T cells (CD4(+), CD8(+), Tregs), B cells, and NK cells, which gave different and even conflicting results. We found that the TLR7/8L:CL097 could simultaneously activate CD8(+) T cells, B cells, and NK cells plus block Treg suppression of T cells and B cells. The TLRLs TLR1/2L:Pam3CSK4, TLR5L:flagellin, TLR4L:LPS, and TLR8/7L:CL075 also blocked Treg suppression of CD4(+) or CD8(+) T cell proliferation, but not B cell proliferation. Besides CL097, TLR2L:PGN, CL075, and TLR9L:CpG-A, CpG-B, and CpG-C) were strong activators of NK cells. Importantly, we found that Pam3CSK4 could: 1) activate CD4(+) T cell proliferation, 2) inhibit the expansion of IL-10(+) naturally occurring FOXP3(+) Tregs and induction of IL-10(+) CD4(+) Tregs (IL-10-producing type 1 Treg), and 3) block naturally occurring FOXP3(+) Tregs suppressive function. Our results suggest these agents could serve as adjuvants to enhance the efficacy of current immunotherapeutic strategies in cancer patients.

LGR4/GPR48 inactivation leads to aniridia-genitourinary anomalies-mental retardation syndrome defects.

AGR syndrome (the clinical triad of aniridia, genitourinary anomalies, and mental retardation, a subgroup of WAGR syndrome for Wilm's tumor, aniridia, genitourinary anomalies, and mental retardation) is a rare syndrome caused by a contiguous gene deletion in the 11p13-14 region. However, the mechanisms of WAGR syndrome pathogenesis are elusive. In this study we provide evidence that LGR4 (also named GPR48), the only G-protein-coupled receptor gene in the human chromosome 11p12-11p14.4 fragment, is the key gene responsible for the diseases of AGR syndrome. Deletion of Lgr4 in mouse led to aniridia, polycystic kidney disease, genitourinary anomalies, and mental retardation, similar to the pathological defects of AGR syndrome. Furthermore, Lgr4 inactivation significantly increased cell apoptosis and decreased the expression of multiple important genes involved in the development of WAGR syndrome related organs. Specifically, deletion of Lgr4 down-regulated the expression of histone demethylases Jmjd2a and Fbxl10 through cAMP-CREB signaling pathways both in mouse embryonic fibroblast cells and in urinary and reproductive system mouse tissues. Our data suggest that Lgr4, which regulates eye, kidney, testis, ovary, and uterine organ development as well as mental development through genetic and epigenetic surveillance, is a novel candidate gene for the pathogenesis of AGR syndrome.

Towards an off-the-shelf vaccine therapy targeting shared B-cell tumor idiotypes.

The ideal tumor antigen is one expressed selectively by the tumor, present in all cancer patients, essential for tumor survival and nonetheless able to induce both humoral and cellular immune response. The personalized idiotype (Id) of the surface immunoglobulin is a tumor specific antigen in that it is expressed on clonal B-cell tumors, mediates B-cell survival, and induces tumor specific immunity in both human and animal models. With the availability of monoclonal antibodies against B cells, such as rituximab, the cellular immune response mediated by specific T cells has gained more importance as a combination therapy for the complete elimination of residual tumor cells in lymphoma and myeloma.

Lgr4 in ocular development and glaucoma.

The leucine-rich repeat-containing G protein-coupled receptor 4 (LGR4, also called GPR48) plays a key role in multiple developmental processes, and mice lacking Lgr4 display anterior segment dysgenesis leading to early-onset glaucomatous retinal ganglion cell loss as well as defective eyelid formation. This paper will review Lgr4 signaling and its regulation of the Axenfeld-Rieger syndrome gene Pitx2, a crucial developmental transcription factor. In addition, Wnt signaling plays an important role in eye development, with Norrin functioning to activate the Wnt receptor Frizzled 4 required for proper retinal vascularization. Recent discoveries identifying Lgr4 as a receptor for Norrin highlight the potential for Lgr4 function in retinal vascularization. Finally, several unanswered questions impeding a full understanding of Lgr4 in glaucoma are considered as avenues for further research.

Identification of prostate-specific G-protein coupled receptor as a tumor antigen recognized by CD8(+) T cells for cancer immunotherapy.

BACKGROUND: Prostate cancer is the most common cancer among elderly men in the US, and immunotherapy has been shown to be a promising strategy to treat patients with metastatic castration-resistant prostate cancer. Efforts to identify novel prostate specific tumor antigens will facilitate the development of effective cancer vaccines against prostate cancer. Prostate-specific G-protein coupled receptor (PSGR) is a novel antigen that has been shown to be specifically over-expressed in human prostate cancer tissues. In this study, we describe the identification of PSGR-derived peptide epitopes recognized by CD8(+) T cells in an HLA-A2 dependent manner. METHODOLOGY/PRINCIPAL FINDINGS: Twenty-one PSGR-derived peptides were predicted by an immuno-informatics approach based on the HLA-A2 binding motif. These peptides were examined for their ability to induce peptide-specific T cell responses in peripheral blood mononuclear cells (PBMCs) obtained from either HLA-A2(+) healthy donors or HLA-A2(+) prostate cancer patients. The recognition of HLA-A2 positive and PSGR expressing LNCaP cells was also tested. Among the 21 PSGR-derived peptides, three peptides, PSGR3, PSGR4 and PSGR14 frequently induced peptide-specific T cell responses in PBMCs from both healthy donors and prostate cancer patients. Importantly, these peptide-specific T cells recognized and killed LNCaP prostate cancer cells in an HLA class I-restricted manner. CONCLUSIONS/SIGNIFICANCE: We have identified three novel HLA-A2-restricted PSGR-derived peptides recognized by CD8(+) T cells, which, in turn, recognize HLA-A2(+) and PSGR(+) tumor cells. The PSGR-derived peptides identified may be used as diagnostic markers as well as immune targets for development of anticancer vaccines.

TCL1: a shared tumor-associated antigen for immunotherapy against B-cell lymphomas.

Immunotherapy with therapeutic idiotype vaccines offers promise for treatment of B-cell malignancies. However, identification of novel immunogenic lymphoma-associated antigens that are universally expressed is necessary to overcome the barriers of patient-specific idiotype vaccines. Here, we determined whether T-cell leukemia/lymphoma 1 (TCL1) oncoprotein encoded by the TCL1 gene could be a target for immunotherapy of B-cell malignancies. We show that TCL1 mRNA and protein are selectively expressed in normal B cells but markedly hyperexpressed in multiple human B-cell lymphomas, including follicular lymphoma, chronic lymphocytic leukemia, mantle cell lymphoma, diffuse large B-cell lymphoma, and splenic marginal zone B-cell lymphoma. We demonstrated that TCL1-specific CD8(+) T cells can be generated from HLA-A*0201 (HLA-A2)(+) normal donors and identified TCL1(71-78) (LLPIMWQL) as the minimal epitope recognized by these T cells. More importantly, TCL1(71-78) peptide-specific T cells were present in the peripheral blood and tumor-infiltrating lymphocytes of lymphoma patients, could be expanded in vitro, and lysed autologous tumor cells but not normal B cells in an HLA-A2-restricted manner. Our results suggest that TCL1 is naturally processed and presented on the surface of lymphoma cells for recognition by cytotoxic T cells and can serve as a novel target for development of immunotherapeutic strategies against common B-cell lymphomas.

Targeting human B-cell malignancies through Ig light chain-specific cytotoxic T lymphocytes.

PURPOSE: The variable regions of Ig (idiotype, Id) expressed by malignant B cells can be used as tumor-specific antigens that induce humoral and cellular immunity. However, epitopes derived from Id that stimulate human CD8(+) T-cell immunity are incompletely characterized. EXPERIMENTAL DESIGN: The clonal Ig V(L) of human myeloma cell line U266 and five primary B-cell tumors were sequenced, and peptides corresponding to the Ig V(L) region were tested for their ability to stimulate CTLs from 10 HLA-A*0201-positive normal donors. The CTLs thus generated were tested against peptide-pulsed T2 cells and autologous tumor cells. RESULTS: Fourteen peptides derived from Ig light chain (V(L)) of U266 and primary B-cell tumors were used to generate 68 CTLs lines that specifically produced IFN-γ when cocultured with peptide-pulsed T2 cells. These CTLs lysed peptide-pulsed T2 cell as well as U266 or autologous tumor targets in an HLA class I-dependent manner. Sequence analysis revealed shared V(L) T-cell epitopes in U266 and primary B-cell tumors, not previously reported within Ig heavy chain (V(H)) sequences. CONCLUSION: This study thus identifies novel immunogenic CTLs epitopes from Id V(L), suggests that they are naturally presented on the surface of B-cell malignancies, and supports their inclusion in next-generation Id vaccines. The ability to prime T cells derived from normal HLA-matched donors, rather than patients, may also have direct application to current strategies, designed to generate allogeneic tumor-specific T cells for adoptive transfer.