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1.
Targeting breast and prostate cancers through their hormone receptors   总被引:2,自引:0,他引:2  
A targeted treatment that effectively destroys human breast, prostate, ovarian, and testicular cancer cells that express luteinizing hormone/chorionic gonadotropin (LH/CG) receptors has been developed. The treatment consists of a conjugate of a membrane-disrupting lytic peptide (Hecate, Phor14, or Phor21) and a 15-amino acid segment of the beta chain of CG. Because these conjugates act primarily by destroying cell membranes, their effects are independent of cell proliferation. The conjugates are relatively small molecules, are rapidly metabolized, and are not antigenic. In a series of independent experiments conducted in three different laboratories, the validity of the concept has been established, and it has been shown that the LH/CG receptor capacity of the cancer cells is directly related to the sensitivity of the lytic peptide conjugates. Sensitivity to the drugs can be increased by pretreating prostate or breast cancer cells with FSH or estradiol to up-regulate LH/CG receptors. A series of 23 in vivo experiments involving a total of 1630 nude mice bearing xenografts of human prostate or breast cancer cells showed convincingly that all three lytic peptide-betaCG compounds were highly effective in destroying tumors and reducing tumor burden. Hecate-betaCG was less effective in mice bearing ovarian epithelial cancer cell xenografts, but was highly effective in treating granulosa cell tumors in transgenic mice. In addition, Hecate-betaCG and Phor14-betaCG were highly effective in targeting and destroying prostate and breast cancer cell metastases in the presence or absence of the primary tumors. Although effective in vitro, neither Hecate nor Phor14 alone were effective in reducing primary tumor volume or burden in nude mice bearing prostate or breast cancer xenografts.  相似文献   

2.
In series of experiments conducted in vitro, we have established the concept that conjugates of the lytic peptides Hecate or Phor14 with a fragment of the beta chain of LH (amino acids 80-94) selectively destroy both androgen sensitive and insensitive human prostate cancer cells. Extraction of steroids from the culture medium by charcoal reduced the ability of the conjugates to kill LNCaP, BRF41T and PC-3 cells. Addition of hormones known to up-regulate LH receptors (estradiol, testosterone or FSH) to the culture medium restored the ability of the conjugates to kill these cell lines. The toxicity of the conjugates (EC(50)) to these cell lines was closely correlated to their LH binding capacities (f mol/10(6) cells). In series of in vivo experiments we have shown that both the Hecate and Phor14-betaLH conjugates are remarkably effective in causing tumor cell necrosis and cessation of tumor growth in nude athymic mice. Treatment with Hecate-betaLH (12 mg/kg body weight) resulted in a reduction of tumor burden (mg tumor/g body weight) from 60 to 14 (P<0.0001); treatment with Phor14-betaLH (12 mg/kg body weight) reduced tumor burden to 27 mg (P<0.0001). Treatment with a high dose of Phor14-betaLH (24 mg/kg body weight) reduced the tumor burden from 60 to 12 mg/kg P<0.0001). Pretreatment of animals receiving a low dose of Phor14-betaLH (12 mg/kg) with either estradiol or follicle stimulating hormone, (FSH) resulted in reduction of tumor burden from 60 to 11 mg/kg. Administration of a second 3-week treatment after a one month recovery period caused complete regression of more than 75 percent of the tumors. No changes in body weight or histological abnormalities were found in any of the organs examined, except the testes.  相似文献   

3.
The main objective of this experiment was to determine and compare the effects of two lytic peptide conjugates, Phor21-?CG(ala) and ?CG(ala)-Phor21, at a low therapeutic dose (0.2 mg/kg body weight i.v.), on periovulatory ovarian and endocrine activity, and ensuing luteal function in an ovine experimental model. We hypothesized that the dense expression of LH/hCG receptors on the preovulatory follicle would present an appropriate target for the drugs and disrupt normal ovarian dynamics in sheep. Serum levels of reproductive hormones and ultrasonographic images were used for the assessment of periovulatory events following drug administration in 14 Rideau Arcott ewes; seven animals served as controls. Ovulations were synchronized with intravaginal progestogen-releasing sponges (medroxyprogesterone acetate, 60 mg) that were left in place for 12 days and a single i.m. injection of 750 IU of equine chorionic gonadotropin (eCG) given at sponge withdrawal. Both drugs were administered by i.v. injection 36 h post sponge removal/eCG injection, during the period of increasing LH responsiveness of potential ovulatory follicles and around the expected onset of the preovulatory surge of gonadotropins. No difference (p>0.05) was detected in the number of luteal structures per ewe in control versus treated animals during early luteogenesis. After drug administration, peak FSH concentrations were higher (p<0.05) in Phor21-?CG(ala)-treated compared to control ewes and circulating estradiol concentrations were lower (p<0.05) in ?CG(ala)-Phor21-treated animals. Mean serum progesterone concentrations were lower (p<0.05) in ?CG(ala)-Phor21-treated than control ewes during the luteal phase post-treatment. There were no differences (p>0.05) in the percentage of ewes that lambed or lamb characteristics between the three groups at lambing 9 months post-treatment. In summary, neither Phor21-?CG(ala) nor ?CG(ala)-Phor21 demonstrated adverse effects on the ovulatory process but the treatment with ?CG(ala)-Phor21 significantly depressed follicular and luteal steroidogenesis. With a lack of evidence for disruptive effects on endocrine function and fertility, these obsevations support the use of Phor21-?GG(ala) as a cancer pharmaceutical.  相似文献   

4.
Purpose Prostate cancer refractory to hormonal manipulation requires new treatment modalities. In the present study we attempted to identify prostate stem cell antigen (PSCA)-derived peptides immunogenic in HLA-A2+ prostate cancer patients in order to develop peptide-based immunotherapy against hormone-refractory prostate cancer (HRPC).Methods Eleven different PSCA-derived peptides, which were prepared based on the HLA-A2 binding motif, were examined to determine whether they would be recognized by cellular and humoral immune responses in 12 HLA-A2+ patients (11 with HRPC and 1 with non-HRPC).Results Among the PSCA-derived peptides, PSCA 7–15 and PSCA 21–30 peptides effectively induced HLA-A2-restricted peptide-specific and tumor-reactive cytotoxic T lymphocytes (CTLs) from peripheral blood mononuclear cells (PBMCs) of HLA-A2+ patients. The PSCA 21–30 peptide was capable of inducing peptide-specific CTLs in both cancer patients and healthy donors, whereas the PSCA 7–15 peptide was immunogenic in only cancer patients. Immunoglobulin G (IgG) reactive to the PSCA 21–30 peptide was detected in plasma of most patients and healthy donors, whereas IgG reactive to PSCA 7–15 was undetectable in all cases. These results indicate that the former peptide elicits both cellular and humoral immune responses in both patients and healthy donors, whereas the latter elicits only cellular responses in patients.Conclusion These two PSCA peptides should be considered for use in clinical trials of immunotherapy for HLA-A2+ HRPC patients.  相似文献   

5.
Considerable variation in antibody response (AR) was observed among recipients of an injectable typhoid vaccine and an oral cholera vaccine. We sought to find whether polymorphisms in genes of the immune system, both innate and adaptive, were associated with the observed variation in response. For both vaccines, we were able to discover and validate several polymorphisms that were significantly associated with immune response. For the typhoid vaccines, these polymorphisms were on genes that belonged to pathways of polysaccharide recognition, signal transduction, inhibition of T-cell proliferation, pro-inflammatory signalling and eventual production of antimicrobial peptides. For the cholera vaccine, the pathways included epithelial barrier integrity, intestinal homeostasis and leucocyte recruitment. Even though traditional wisdom indicates that both vaccines should act as T-cell-independent antigens, our findings reveal that the vaccines induce AR using different pathways.  相似文献   

6.
Prostate cancer (PCa) is one of the most common types of cancer in men in the United States and is the second leading cause of cancer related death in men. Clinically, secreted prostate specific antigen (PSA) has gained recognition because of its proteolytic activity being directly linked to PCa cell proliferation leading to disease initiation and progression. Using phage display technology, we identified four distinct cyclical peptides. These peptides apart from differences in their amino acid sequence, elicited minimal cross reactive antibody responses against each other. One of the four peptides analyzed produced an antibody response that recognizes the PSA protein. We demonstrate that the synthetic PSA peptide mimics identified in our study are immunologically active and produce neutralizing activity and this has relevance and utility for prostate cancer disease progression.  相似文献   

7.
The androgen receptor (AR) is a hormone receptor that plays a critical role in prostate cancer, and depletion of its ligand has long been the cornerstone of treatment for metastatic disease. Here, we evaluate the AR ligand-binding domain (LBD) as an immunological target, seeking to identify HLA-A2-restricted epitopes recognized by T cells in prostate cancer patients. Ten AR LBD-derived, HLA-A2-binding peptides were identified and ranked with respect to HLA-A2 affinity and were used to culture peptide-specific T cells from HLA-A2+ prostate cancer patients. These T-cell cultures identified peptide-specific T cells specific for all ten peptides in at least one patient, and T cells specific for peptides AR805 and AR811 were detected in over half of patients. Peptide-specific CD8+ T-cell clones were then isolated and characterized for prostate cancer cytotoxicity and cytokine expression, identifying that AR805 and AR811 CD8+ T-cell clones could lyse prostate cancer cells in an HLA-A2-restricted fashion, but only AR811 CTL had polyfunctional cytokine expression. Epitopes were confirmed using immunization studies in HLA-A2 transgenic mice, in which the AR LBD is an autologous antigen with an identical protein sequence, which showed that mice immunized with AR811 developed peptide-specific CTL that lyse HLA-A2+ prostate cancer cells. These data show that AR805 and AR811 are HLA-A2-restricted epitopes for which CTL can be commonly detected in prostate cancer patients. Moreover, CTL responses specific for AR811 can be elicited by direct immunization of A2/DR1 mice. These findings suggest that it may be possible to elicit an anti-prostate tumor immune response by augmenting CTL populations using AR LBD-based vaccines.  相似文献   

8.

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.  相似文献   

9.
Despite monolayer cultures being widely used for cancer drug development and testing, 2D cultures tend to be hypersensitive to chemotherapy and are relatively poor predictors of whether a drug will provide clinical benefit. Whilst generally more complicated, three dimensional (3D) culture systems often better recapitulate true cancer architecture and provide a more accurate drug response. As a step towards making 3D cancer cultures more accessible, we have developed a microwell platform and surface modification protocol to enable high throughput manufacture of 3D cancer aggregates. Herein we use this novel system to characterize prostate cancer cell microaggregates, including growth kinetics and drug sensitivity. Our results indicate that prostate cancer cells are viable in this system, however some non-cancerous prostate cell lines are not. This system allows us to consistently control for the presence or absence of an apoptotic core in the 3D cancer microaggregates. Similar to tumor tissues, the 3D microaggregates display poor polarity. Critically the response of 3D microaggregates to the chemotherapeutic drug, docetaxel, is more consistent with in vivo results than the equivalent 2D controls. Cumulatively, our results demonstrate that these prostate cancer microaggregates better recapitulate the morphology of prostate tumors compared to 2D and can be used for high-throughput drug testing.  相似文献   

10.
Kallikrein 14 (KLK14) has been proposed as a useful prognostic marker in prostate cancer, with expression reported to be associated with tumour characteristics such as higher stage and Gleason score. KLK14 tumour expression has also shown the potential to predict prostate cancer patients at risk of disease recurrence after radical prostatectomy. The KLKs are a remarkably hormone-responsive family of genes, although detailed studies of androgen regulation of KLK14 in prostate cancer have not been undertaken to date. Using in vitro studies, we have demonstrated that unlike many other prostatic KLK genes that are strictly androgen responsive, KLK14 is more broadly expressed and inversely androgen regulated in prostate cancer cells. Given these results and evidence that KLK14 may play a role in prostate cancer prognosis, we also investigated whether common genetic variants in the KLK14 locus are associated with risk and/or aggressiveness of prostate cancer in approximately 1200 prostate cancer cases and 1300 male controls. Of 41 single nucleotide polymorphisms assessed, three were associated with higher Gleason score (≥7): rs17728459 and rs4802765, both located upstream of KLK14, and rs35287116, which encodes a p.Gln33Arg substitution in the KLK14 signal peptide region. Our findings provide further support for KLK14 as a marker of prognosis in prostate cancer.  相似文献   

11.
Cancer vaccines as a modality of immune-based cancer treatment offer the promise of a non-toxic and efficacious therapeutic alternative for patients. Emerging data suggest that response to vaccination largely depends on the magnitude of the type I immune response generated, epitope spreading and immunogenic modulation of the tumor. Moreover, accumulating evidence suggests that cancer vaccines will likely induce better results in patients with low tumor burden and less aggressive disease. To induce long-lasting clinical responses, vaccines will need to be combined with immunoregulatory agents to overcome tumor-related immune suppression. Immunotherapy, as a treatment modality for prostate cancer, has received significant attention in the past few years. The most intriguing characteristics that make prostate cancer a preferred target for immune-based treatments are (1) its relative indolence which allows sufficient time for the immune system to develop meaningful antitumor responses; (2) prostate tumor-associated antigens are mainly tissue-lineage antigens, and thus, antitumor responses will preferentially target prostate cancer cells. But, also in the event of eradication of normal prostate epithelium as a result of immune attack, this will have no clinical consequences because the prostate gland is not a vital organ; (3) the use of prostate-specific antigen for early detection of recurrent disease allows for the initiation of vaccine immunotherapy while tumor burden is still minimal. Finally, for improving clinical outcome further to increasing vaccine potency, it is imperative to recognize prognostic and predictive biomarkers of clinical benefit that may guide to select the therapeutic strategies for patients most likely to gain benefit.  相似文献   

12.
目的:探讨分析前列腺癌患者^89Sr治疗后机体免疫功能的变化及其临床意义。方法:87例前列腺癌患者经^89Srcl2治疗1月,采用流式细胞术检测治疗前后其外周血淋巴细胞亚群,速率散射免疫比浊分析法检测其免疫球蛋白的含量。结果:经^89Sr治疗后,患者CD3、CD19、CD4比例均明显升高,CD8比例明显降低,差异均有统计学意义畔0.05),而CD16^+CD56^+无明显变化;IgG和IgA明显升高,差异均有统计学意义(P〈0.05),而IgM无明显变化。结论:用^89Srcl2治疗前列腺癌可以有效提高患者的免疫水平,可通过监测机体免疫功能指标的变化^89Sr核素的疗效。  相似文献   

13.
We have recently identified and validated the prostate cancer antigen Tomoregulin as a target for the radioimmunotherapy for prostate cancer. Here, we provide evidence that Tomoregulin is an internalizing antigen and a potential target for immunotoxins. First, the cell surface localization of Tomoregulin was confirmed by flow cytometry, and its expression levels were determined by whole-cell binding assays. Second, laser scanning confocal microscopy revealed Tomoregulin internalization into the cytoplasm on antibody binding at 37 degrees C. The internalized Tomoregulin was found to colocalize with acidic vesicles. Third, internalization kinetics assays using (125)I-labeled anti-Tomoregulin mouse monoclonal antibody 2H8 demonstrated that the amount of internalized antigen-antibody complexes increased with time and reached approximately 25% of the total surface antigen after 60 to 90 minutes. Because 2H8 is capable of binding to Tomoregulin on the cell surface and can be internalized, we finally evaluated 2H8 as a means of targeting toxic payloads to prostate cancer cells. 2H8 was coupled to the cytotoxin saporin through a secondary antibody (Mab-ZAP) in indirect immunotoxin assays. Cell killing occurred on Tomoregulin-positive cells (Clone69) at the immunotoxin concentrations not affecting the Tomoregulin-negative cells (PC-3). In contrast to 2H8, the control antibody (mouse anti-c-Myc antibody 9E10) had no effect on cells in the presence of Mab-ZAP. Thus, Tomoregulin internalization confers selective cytotoxicity of immunotoxins on prostate cancer cells, and Tomoregulin-mediated delivery of immunotoxin has potential as a prostate cancer therapy.  相似文献   

14.
15.
Human kallikrein 2 (hK2) is a serine protease produced by the secretory epithelial cells in the prostate. Because hK2 activates several factors participating in proteolytic cascades that may mediate metastasis of prostate cancer, modulation of the activity of hK2 is a potential way of preventing tumor growth and metastasis. Furthermore, specific ligands for hK2 are potentially useful for targeting and imaging of prostate cancer and for assay development. We have used enzymatically active recombinant hK2 captured by a monoclonal antibody exposing the active site of the enzyme to screen phage display peptide libraries. Using libraries expressing 10 or 11 amino acids long linear peptides, we identified six different peptides binding to hK2. Three of these were shown to be specific and efficient inhibitors of the enzymatic activity of hK2 toward a peptide substrate. Furthermore, the peptides inhibited the activation of the proform of prostate-specific antigen by hK2. Amino acid substitution analyses revealed that motifs of six amino acids were required for the inhibitory activity. These peptides are potentially useful for treatment and targeting of prostate cancer.  相似文献   

16.
We describe a novel approach for high-throughput analysis of the immune response in cancer patients using phage-based microarray technology. The recombinant phages used for fabricating phage arrays were initially selected via the use of random peptide phage libraries and breast cancer patient serum antibodies. The peptides displayed by the phages retained their ability to be recognized by serum antibodies after immobilization. The recombinant phage microarrays were screened against either breast cancer or healthy donor serum antibodies. A model-based statistical method is proposed to estimate significant differences in serum antibody reactivity between patients and normals. A significant tumor effect was found with most of the selected phage-displayed peptides, suggesting that recombinant phage microarrays can serve as a tool in monitoring humoral responses towards phage-displayed peptides.  相似文献   

17.
Though the current therapies are effective at clearing an early stage prostate cancer, they often fail to treat late-stage metastatic disease. We aimed to investigate the molecular mechanisms underlying the anticancer effects of a natural triterpenoid, ganoderic acid DM (GA-DM), on two human prostate cancer cell lines: the androgen-independent prostate carcinoma (PC-3), and androgen-sensitive prostate adenocarcinoma (LNCaP). Cell viability assay showed that GA-DM was relatively more toxic to LNCaP cells than to PC-3 cells (IC50s ranged 45-55 µM for PC-3, and 20-25 µM for LNCaP), which may have occurred due to differential expression of p53. Hoechst DNA staining confirmed detectable nuclear fragmentation in both cell lines irrespective of the p53 status. GA-DM treatment decreased Bcl-2 proteins while it upregulated apoptotic Bax and autophagic Beclin-1, Atg5, and LC-3 molecules, and caused an induction of both early and late events of apoptotic cell death. Biochemical analyses of GA-DM-treated prostate cancer cells demonstrated that caspase-3 cleavage was notable in GA-DM-treated PC-3 cells. Interestingly, GA-DM treatment altered cell cycle progression in the S phase with a significant growth arrest in the G2 checkpoint and enhanced CD4 + T cell recognition of prostate tumor cells. Mechanistic study of GA-DM-treated prostate cancer cells further demonstrated that calpain activation and endoplasmic reticulum stress contributed to cell death. These findings suggest that GA-DM is a candidate for future drug design for prostate cancer as it activates multiple pathways of cell death and immune recognition.  相似文献   

18.
Histone deacetylases (HDACs) have emerged as important targets for cancer treatment. HDAC-inhibitors (HDACis) are well tolerated in patients and have been approved for the treatment of patients with cutaneous T-cell lymphoma (CTCL). To improve the clinical benefit of HDACis in solid tumors, combination strategies with HDACis could be employed. In this study, we applied Analysis of Functional Annotation (AFA) to provide a comprehensive list of genes and pathways affected upon HDACi-treatment in prostate cancer cells. This approach provides an unbiased and objective approach to high throughput data mining. By performing AFA on gene expression data from prostate cancer cell lines DU-145 (an HDACi-sensitive cell line) and PC3 (a relatively HDACi-resistant cell line) treated with HDACis valproic acid or vorinostat, we identified biological processes that are affected by HDACis and are therefore potential treatment targets for combination therapy. Our analysis revealed that HDAC-inhibition resulted among others in upregulation of major histocompatibility complex (MHC) genes and deregulation of the mitotic spindle checkpoint by downregulation of genes involved in mitosis. These findings were confirmed by AFA on publicly available data sets from HDACi-treated prostate cancer cells. In total, we analyzed 375 microarrays with HDACi treated and non-treated (control) prostate cancer cells. All results from this extensive analysis are provided as an online research source (available at the journal’s website and at http://luigimarchionni.org/HDACIs.html). By publishing this data, we aim to enhance our understanding of the cellular changes after HDAC-inhibition, and to identify novel potential combination strategies with HDACis for the treatment of prostate cancer patients.  相似文献   

19.
Even though an immunogenic formulation of the murine monoclonal anti-EpCAM (epithelian cell adhesion molecule) antibody Mab 17-1A, has been shown to evoke a strong humoral immune response in both, monkey studies and early clinical trials, conventional anti-EpCAM ELISA could not identify anti-EpCAM immune response in relation to treatment with Mab17-1A. In contrast, usage of cellulose membranes prepared by SPOT technology presenting overlapping EpCAM peptides allowed the unequivocal determination of EpCAM related antibodies present in monkeys sera after immunization with IGN101. Based on such contradictory results, it was of high interest to compare obtained data to a different method for better assessment of their possible interpretation. Therefore, in the present studies, some EpCAM peptides, determined as reactive by binding of IgG isolated from sera of treated monkeys on membranes prepared by SPOT technology, were represented on yeast surface using the pYD1 yeast display vector system. Binding of biotinylated IgG from sera was detected with streptavidin–FITC and quantity of binding was determined by FACS measurement. Though using this completely different method, experiments with pre-immune and immune sera of four monkeys exemplarily are comparable to the results obtained by analysis with synthetic peptide arrays.  相似文献   

20.
Despite years of intensive research, breast cancer remains the leading cause of death in women worldwide. New technologies including oncolytic virus therapies, virus, and phage display are among the most powerful and advanced methods that have emerged in recent years with potential applications in cancer prevention and treatment. Oncolytic virus therapy is an interesting strategy for cancer treatment. Presently, a number of viruses from different virus families are under laboratory and clinical investigation as oncolytic therapeutics. Oncolytic viruses (OVs) have been shown to be able to induce and initiate a systemic antitumor immune response. The possibility of application of a multimodal therapy using a combination of the OV therapy with immune checkpoint inhibitors and cancer antigen vaccination holds a great promise in the future of cancer immunotherapy. Display of immunologic peptides on bacterial viruses (bacteriophages) is also increasingly being considered as a new and strong cancer vaccine delivery strategy. In phage display immunotherapy, a peptide or protein antigen is presented by genetic fusions to the phage coat proteins, and the phage construct formulation acts as a protective or preventive vaccine against cancer. In our laboratory, we have recently tested a few peptides (E75, AE37, and GP2) derived from HER2/neu proto-oncogene as vaccine delivery modalities for the treatment of TUBO breast cancer xenograft tumors of BALB/c mice. Here, in this paper, we discuss the latest advancements in the applications of OVs and bacterial viruses display systems as new and advanced modalities in cancer immune therapeutics.  相似文献   

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