efei Yu

Galectin-3C Inhibits Tumor Growth and Increases the Anticancer Activity of Bortezomib in a Murine Model of Human Multiple Myeloma

Galectin-3 is a human lectin involved in many cellular processes including differentiation, apoptosis, angiogenesis, neoplastic transformation, and metastasis. We evaluated galectin-3C, an N-terminally truncated form of galectin-3 that is thought to act as a dominant negative inhibitor, as a potential treatment for multiple myeloma (MM). Galectin-3 was expressed at varying levels by all 9 human MM cell lines tested. In vitro galectin-3C exhibited modest anti-proliferative effects on MM cells and inhibited chemotaxis and invasion of U266 MM cells induced by stromal cell-derived factor (SDF)-1α. Galectin-3C facilitated the anticancer activity of bortezomib, a proteasome inhibitor approved by the FDA for MM treatment. Galectin-3C and bortezomib also synergistically inhibited MM-induced angiogenesis activity in vitro. Delivery of galectin-3C intravenously via an osmotic pump in a subcutaneous U266 cell NOD/SCID mouse model of MM significantly inhibited tumor growth. The average tumor volume of bortezomib-treated animals was 19.6% and of galectin-3C treated animals was 13.5% of the average volume of the untreated controls at day 35. The maximal effect was obtained with the combination of galectin-3C with bortezomib that afforded a reduction of 94% in the mean tumor volume compared to the untreated controls at day 35. In conclusion, this is the first study to show that inhibition of galectin-3 is efficacious in a murine model of human MM. Our results demonstrated that galectin-3C alone was efficacious in a xenograft mouse model of human MM, and that it enhanced the anti-tumor activity of bortezomib in vitro and in vivo. These data provide the rationale for continued testing of galectin-3C towards initiation of clinical trials for treatment of MM.

AKAP‐4: a novel cancer testis antigen for multiple myeloma

Purpose Immunotherapy promises to be a more gentle and successful cancer treatment when compared with current standard treatments. Multiple myeloma (MM) is still a fatal hematologic malignancy that represents approximately 1% of all cancers and 2% of all cancer deaths. Approximately 50,000 Americans currently have MM. The research to discover new suitable cancer targets is needed to improve the effects of immunotherapy. The AKAP family9s protein provides an organizing center about which various protein kinases and phosphatases can be assembled to create solid-state signaling devices that can signal, be modulated, and be trafficked within the cell. A member of this family, AKAP-4, is the focus of our study. Human AKAP-4 is a structural protein of the sperm fibrous sheath that also functions to anchor protein kinase A to this structure via the regulatory subunit of the kinase, and seems to be involved in sperm motility. Our aim was to investigate the presence of AKAP-4 as a novel cancer testis antigen target in MM patients. Methods We evaluated the expression of AKAP-4 mRNA in a normal panel of tissues and in 15 MM patients either by PCR and immunocytochemistry. The normal control investigated tissues were kidney, ovary, skeletal muscle, mammary, brain, heart, colon, stomach, liver, lung, pancreas, spleen, trachea, and bone marrow. Summary The analysis of the mRNA expression of AKAP-4 showed that none of the normal tissues produced any positive band signals, whereas 6 of the 15 investigated patients (40%) showed a positive band signal. The immunohistochemical approach to the normal tissue panel showed no staining in any of the evaluated organs, except for the control, the testis. Five of the 15 MM investigated cases (33.3%) showed positive cytoplasmic staining. Conclusion To our knowledge, we established for the first time that AKAP-4 is expressed at the transcriptional level in MM cases, with a rate of 40%, whereas it is not expressed in normal tissues. Immunocytochemical data confirmed the PCR observations even if with a slightly lower percentage rate (33.3%). Since AKAP-4 has yet not been studied in MM, this is the first study that gives evidence of its aberrant expression in MM and suggests its use as possible novel cancer testis antigen target in MM.

Identification of AKAP-4 as a new cancer/testis antigen for detection and immunotherapy of prostate cancer†

Prostate cancer (PC) is the second most common cancer in older men, after skin cancer. PC is difficult to diagnose because the prostate‐specific antigen screening method is associated with many false positives. In addition there is a need to develop new and more effective treatments. Among presently available new treatments, immunotherapy is a promising approach. We investigated the expression of the cancer/testis antigen, AKAP‐4, in PC patients to evaluate the possibility of exploiting AKAP‐4 as a target for immunotherapy.

Cancer Testis Antigen Vaccination Affords Long-Term Protection in a Murine Model of Ovarian Cancer

Sperm protein (Sp17) is an attractive target for ovarian cancer (OC) vaccines because of its over-expression in primary as well as in metastatic lesions, at all stages of the disease. Our studies suggest that a Sp17-based vaccine can induce an enduring defense against OC development in C57BL/6 mice with ID8 cells, following prophylactic and therapeutic treatments. This is the first time that a mouse counterpart of a cancer testis antigen (Sp17) was shown to be expressed in an OC mouse model, and that vaccination against this antigen significantly controlled tumor growth. Our study shows that the CpG-adjuvated Sp17 vaccine overcomes the issue of immunologic tolerance, the major barrier to the development of effective immunotherapy for OC. Furthermore, this study provides a better understanding of OC biology by showing that Th-17 cells activation and contemporary immunosuppressive T-reg cells inhibition is required for vaccine efficacy. Taken together, these results indicate that prophylactic and therapeutic vaccinations can induce long-standing protection against OC and delay tumor growth, suggesting that this strategy may provide additional treatments of human OC and the prevention of disease onset in women with a family history of OC.

Sperm protein 17 is a suitable target for adoptive T-cell-based immunotherapy in human ovarian cancer.

For ovarian cancer (OC) patients with advanced or metastatic disease, standard treatments (chemotherapy and radiotherapy) are not very effective and have undesirable side effects. Newer and more promising approaches in cancer treatment use components of the immune system. In this study, we applied an adoptive immunotherapy-based approach using a cancer testis antigen, sperm protein 17, as a target for the treatment of human metastatic OC in a NOD.CB17-PrkDCcid/J (nonobese, diabetic severe combined immunodeficient) mouse model. We used the human SK-OV-3A2.A3 OC cell line, endogenously expressing sperm protein 17, to induce tumor growth in mice. We provide direct evidence, for the first time, that in vitro cultured, monoclonal, cytotoxic T lymphocytes (derived either from advanced OC patients or from healthy donors), specific for sperm protein 17, can eradicate human metastatic OC cells. In addition, we observed no evidence of autoimmunity after histologic examination of the tissue sections adding to the safety profile of our approach.

rAAV/Her-2/neu Loading of Dendritic Cells for a Potent Cellular-Mediated MHC Class I Restricted Immune Response Against Ovarian Cancer

Recent studies demonstrate that recombinant adeno-associated virus (rAAV)-based antigen loading of dendritic cells (DCs) generates, in vitro, significant and rapid cytotoxic T-lymphocyte (CTL) responses against viral antigens. We used the rAAV system to induce specific CTLs against tumor antigens for the development of ovarian cancer (OC) gene therapy. As an extension of the versatility of the rAAV system, we incorporated a self-antigen, Her-2/neu, which is expressed in many cancers, including breast and ovarian. We analyzed two different vectors containing a short (157-612) and long domain (1-1197). Our rAAV vector induced strong stimulation of CTLs directed against the self tumor antigen, Her-2/neu. We then investigated the efficiency of the CTLs in killing Her-2/neu-targeted cells. A significant MHC class I-restricted, anti-Her-2/neu-specific CTL killing was demonstrated against Her-2/neu-positive OC cells after one in vitro stimulation. In summary, single peripheral blood mononuclear cell (PBMC) stimulation with rAAV/157-612- or rAAV/1-1197-pulsed DCs induces strong antigen-specific CTL generation. The CTLs were capable of lysing low doses of peptides pulsed into target cells or OC Her-2/neu(+) tumors. These data suggest that AAV-based antigen loading of DCs is highly effective for generating human CTL responses against OC antigens.

Galectin-3 inhibition suppresses drug resistance, motility, invasion and angiogenic potential in ovarian cancer

OBJECTIVE Ovarian cancer is the most deadly gynecologic malignancy worldwide. Since the pathogenesis of ovarian cancer is incompletely understood, and there are no available screening techniques for early detection, most patients are diagnosed with advanced, incurable disease. In an effort to develop innovative and effective therapies for ovarian cancer, we tested the effectiveness of Galecti-3C in vitro. This is a truncated, dominant negative form of Galectin-3, which is thought to act by blocking endogenous Galectin-3. METHODS We produced a truncated, dominant-negative form of Galectin-3, namely Galetic-3C. Ovarian cancer cell lines and primary cells from ovarian cancer patients were treated with Galectin-3C, and growth, drug sensitivity, and angiogenesis were tested. RESULT We show, for the first time, that Galectin-3C significantly reduces the growth, motility, invasion, and angiogenic potential of cultured OC cell lines and primary cells established from OC patients. CONCLUSIONS Our findings indicate that Galectin-3C is a promising new compound for the treatment of ovarian cancer.

The pituitary tumor transforming gene 1 (PTTG-1): An immunological target for multiple myeloma

BackgroundMultiple Myeloma is a cancer of B plasma cells, which produce non-specific antibodies and proliferate uncontrolled. Due to the potential relapse and non-specificity of current treatments, immunotherapy promises to be more specific and may induce long-term immunity in patients. The pituitary tumor transforming gene 1 (PTTG-1) has been shown to be a novel oncogene, expressed in the testis, thymus, colon, lung and placenta (undetectable in most other tissues). Furthermore, it is over expressed in many tumors such as the pituitary adenoma, breast, gastrointestinal cancers, leukemia, lymphoma, and lung cancer and it seems to be associated with tumorigenesis, angiogenesis and cancer progression. The purpose was to investigate the presence/rate of expression of PTTG-1 in multiple myeloma patients.MethodsWe analyzed the PTTG-1 expression at the transcriptional and the protein level, by PCR, immunocytochemical methods, Dot-blot and ELISA performed on patients sera in 19 multiple myeloma patients, 6 different multiple myeloma cell lines and in normal human tissue.ResultsWe did not find PTTG-1 presence in the normal human tissue panel, but PTTG-1 mRNA was detectable in 12 of the 19 patients, giving evidence of a 63% rate of expression (data confirmed by ELISA). Four of the 6 investigated cell lines (66.6%) were positive for PTTG-1. Investigations of protein expression gave evidence of 26.3% cytoplasmic expression and 16% surface expression in the plasma cells of multiple myeloma patients. Protein presence was also confirmed by Dot-blot in both cell lines and patients.ConclusionWe established PTTG-1s presence at both the transcriptional and protein levels. These data suggest that PTTG-1 is aberrantly expressed in multiple myeloma plasma cells, is highly immunogenic and is a suitable target for immunotherapy of multiple myeloma.

Tracking human multiple myeloma xenografts in NOD-Rag-1/IL-2 receptor gamma chain-null mice with the novel biomarker AKAP-4

BackgroundMultiple myeloma (MM) is a fatal malignancy ranking second in prevalence among hematological tumors. Continuous efforts are being made to develop innovative and more effective treatments. The preclinical evaluation of new therapies relies on the use of murine models of the disease.MethodsHere we describe a new MM animal model in NOD-Rag1null IL2rgnull (NRG) mice that supports the engraftment of cell lines and primary MM cells that can be tracked with the tumor antigen, AKAP-4.ResultsHuman MM cell lines, U266 and H929, and primary MM cells were successfully engrafted in NRG mice after intravenous administration, and were found in the bone marrow, blood and spleen of tumor-challenged animals. The AKAP-4 expression pattern was similar to that of known MM markers, such as paraproteins, CD38 and CD45.ConclusionsWe developed for the first time a murine model allowing for the growth of both MM cell lines and primary cells in multifocal sites, thus mimicking the disease seen in patients. Additionally, we validated the use of AKAP-4 antigen to track tumor growth in vivo and to specifically identify MM cells in mouse tissues. We expect that our model will significantly improve the pre-clinical evaluation of new anti-myeloma therapies.

Protective CD8+ T-cell responses to cytomegalovirus driven by rAAV/GFP/IE1 loading of dendritic cells

BackgroundRecent studies demonstrate that recombinant adeno-associated virus (rAAV)-based antigen loading of dendritic cells (DCs) generates in vitro, significant and rapid cytotoxic T-lymphocyte (CTL) responses against viral antigens.MethodsWe used the rAAV system to induce specific CTLs against CVM antigens for the development of cytomegalovirus HCMV) gene therapy. As an extension of the versatility of the rAAV system, we incorporated immediate-early 1 (IE1), expressed in HCMV. Our rAAV vector induced a strong stimulation of CTLs directed against the HCMV antigen IE1. We then investigated the efficiency of the CTLs in killing IE1 targeted cells.ResultsA significant MHC Class I-restricted, anti-IE1-specific CTL killing was demonstrated against IE1 positive peripheral blood mononuclear cells (PBMC) after one, in vitro, stimulation.ConclusionIn summary, single PBMC stimulation with rAAV/IE1 pulsed DCs induces strong antigen specific-CTL generation. CTLs were capable to lyse low doses of peptides pulsed into target cells. These data suggest that AAV-based antigen loading of DCs is highly effective for generating human CTL responses against HCMV antigens.