Anti-Sp17 monoclonal antibody-doxorubicin conjugates as molecularly targeted chemotherapy for ovarian carcinoma.

Sperm protein 17 (Sp17) is selectively overexpressed in several human malignancies including ovarian carcinoma, but is absent or expressed at low levels in most normal tissues. Previous work from our group characterized an anti-Sp17 monoclonal antibody (clone 3C12) and showed that it specifically targeted tumor cells. In this report, we investigated whether a novel immunoconjugate containing 3C12 linked to the chemotherapeutic agent doxorubicin [(DOX) Adriamycin] had antitumor activity against ovarian cancer cell lines and tumor models. DOX was conjugated to 3C12 using a linker, and the specificity of 3C12-DOX was examined in Sp17-positive SKOV3 and Sp17-negative COC2 ovarian cancer cells using cell-based ELISA and internalization assays. The cytotoxicity of 3C12-DOX was assessed with the MTT assay, and its therapeutic effectiveness was evaluated in immunodeficient mice bearing SKOV3 cells. In vitro, the 3C12-DOX immunoconjugate specifically bound to and was internalized by Sp17-positive SKOV3 cells but did not bind to Sp17-negative cells. Treatment with 3C12-DOX (0.001 to 10 µg/mL) decreased the viability of SKOV3 cells in a Sp17-specific manner. In vivo, 3C12-DOX (3 mg/kg) induced the regression of established SKOV3 xenograft tumors in BALB/c mice compared with control treatment. The antitumor effects of 3C12-DOX were significantly associated with the induction of apoptosis in tumor cells. In addition, 3C12-DOX showed no observable adverse effects or toxicity when compared with DOX alone in mice bearing ovarian tumor xenografts. Our findings suggest that 3C12-DOX may be a potential antibody-drug conjugate for clinical development.

Sperm protein 17, MAGE-C1 and NY-ESO-1 in hepatocellular carcinoma: expression frequency and their correlation with clinical parameters.

UNLABELLED: This study is dedicated to investigate the expression patterns of sperm protein 17 (Sp17), melanoma-specific antigen (MAGE)-C1 and New York esophageal squamous cell carcinoma-1 (NY-ESO-1), to explore the correlation between these cancer-testis antigens and clinical parameters, and to evaluate their values in diagnosis and differentiation of hepatocellular carcinoma. METHODS: Immunohistochemical staining was performed in 45 paraffin-embedded hepatocellular carcinoma specimens. 45 normal peripheral hepatic tissues collected from adjacent non-cancerous areas were used as controls. RESULTS: Positive results of immunohistostaining were obtained in 16 (35.6%), 7 (15.6%) and 36 (80.0%) samples using MAGE-C1, NY-ESO-1 and Sp17 antibodies, respectively. The immunoreactivity of Sp17 was also found in 7 (14.0%) control samples. A statistical correlation between the frequency of Sp17 expression and tumor differentiation grade in hepatocellular carcinoma was confirmed. CONCLUSIONS: Sp17 is highly expressed in hepatocellular carcinoma cells. The frequency of Sp17 expression is closely related to the pathologic differentiation in hepatocellular carcinoma.

Surveillance study of species distribution, antifungal susceptibility and mortality of nosocomial candidemia in a tertiary care hospital in China.

BACKGROUND: Bloodstream infections due to Candida species cause significant morbidity and mortality, and the epidemiology of Candida infection is changing. Surveillance for candidemia is necessary to detect trends in species distribution and antifungal resistance. METHODS: The medical and electronic records of all patients who had candidemia at the authors' hospital from 2009 to 2011 were reviewed for demographic data and clinical information, including the infecting Candida species, resistance to antifungals and survival, and the presence of risk factors associated with candidemia. RESULTS: A total of 133 distinct episodes of candidemia were identified over the study period. The annual incidence of candidemia ranged between 0.71 and 0.85 cases/1000 hospital discharges. The most frequent Candida species were C. tropicalis (28.6%), followed by C. albicans (23.3%) and C. parapsilosis (19.5%). The rates of susceptibility to antifungal agents were as followed: voriconazole (97.8%), itraconazole (69.5%), fluconazole (46.1%), ketoconazole (38.9%). Out of 131 evaluable patients, 34 (26.0%) died within 30 days from the onset of candidemia. C. tropicalis candidemia was associated with the highest mortality rate (44.7%). Regarding the crude mortality in the different units, patients in Hemato-Oncology ward had the highest mortality rate (66.7%), followed by patients in cardiovascular wards and ICU (57.1% and 25.6%, respectively). Predictors of 30-day mortality were identified by uni- and multivariate analyses. Complicated abdominal surgery, presence of central venous catheter (CVC), neutropenia, candidemia due to C. tropicalis and poor treatment with fluconazole were significantly associated with the 30-day mortality. Presence of CVC (odds ratio[OR] = 4.177; 95% confidence interval [CI] = 1.698 to 10.278; P = 0.002) was the only independent predictor for mortality in the multivariate analysis. CONCLUSION: This report provides baseline data for future epidemiological and susceptibility studies and for the mortality rates associated with candidemia in our hospital. The knowledge of the local epidemiological trends in Candida species isolated in blood cultures is important to guide therapeutic choices.

Anti-Sp17 monoclonal antibody with antibody-dependent cell-mediated cytotoxicity and complement-dependent cytotoxicity activities against human ovarian cancer cells.

Sperm protein 17 (Sp17) is a cancer testis antigen that has been shown to be overexpressed in a variety of gynecologic malignancies, in particular ovarian cancer. Emerging evidences indicate that Sp17 is involved in tumorigenesis and in the migration of malignant cells. It has been proposed as a useful target for tumor-vaccine strategies and a novel marker to define tumor subsets and predict drug response. However, the antitumor activity of anti-Sp17 monoclonal antibody (anti-Sp17 mAb) has not been investigated. In this study, the in vitro cytotoxicity, antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) activities of anti-Sp17 mAb were evaluated using Sp17-positive ovarian cancer cells as targets, Sp17-negative ovarian cancer cells as the control, and healthy human peripheral blood monocytes and healthy human serum as effectors. Our preliminary results indicate that the direct cytotoxicity of anti-Sp17 mAb against the investigated ovarian cancer cells was very weak. However, the cytotoxicity of anti-Sp17 mAb, mediated by peripheral blood mononuclear cells (PBMCs), as ADCC, or by human serum, as CDC, was relatively strong in the Sp17-positive ovarian cancer cells. This finding suggested that anti-Sp17 mAb could be a useful tool against ovarian cancer and may provide insight into the development of low side-effect targeting therapy for this malignant disease.

In vivo molecular targeting effects of anti-Sp17- ICG-Der-02 on hepatocellular carcinoma evaluated by an optical imaging system.

BACKGROUND: As the expression of human sperm protein 17 (Sp17) in normal tissue is limited and the function is obscure, its aberrant expression in malignant tumors makes it to be a candidated molecular marker for tumor imaging diagnosis and targeting therapy of the diseases.The aim of this research is to evaluate the targeting effects of anti-sperm protein 17 monoclonal antibody (anti-Sp17) on cancer in vivo and investigate its usefulness as a reagent for molecular imaging diagnosis. METHODS: Immunohistochemistry was used to identify the expression of Sp17 in a hepatocellular carcinoma cell line and tumor xenograft specimens. A near infrared fluorescence dye, ICG-Der-02, was covalently linked to anti-Sp17 for in vivo imaging. The immuno-activity of the anti-Sp17-ICG-Der-02 complex was tested in vitro by ELISA; it was then injected into tumor-bearing nude mice through the caudal vein to evaluate its tumor targeting effect by near infrared imaging system. RESULTS: Overexpression of Sp17 on the surface of the hepatocellular carcinoma cell line SMMC-7721 was demonstrated. Anti-Sp17-ICG-Der-02 with immuno-activity was successfully synthesized. The immuno-activity and photo stability of anti-Sp17- ICG-Der-02 showed good targeting capability for Sp17 expressing tumor models (SMMC-7721) in vivo, and its accumulation in the tumor lasted for at least 7 days. CONCLUSIONS: Anti-Sp17 antibody targeted and accumulated in Sp17 positive tumors in vivo, which demonstrated its capability of serving as a diagnostic reagent.

Sperm protein 17 is highly expressed in endometrial and cervical cancers.

BACKGROUND: Sperm protein 17 (Sp17) is a highly conserved mammalian protein in the testis and spermatozoa and has been characterized as a tumor-associated antigen in a variety of human malignancies. Many studies have examined the role of Sp17 in tumorigenesis and the migration of malignant cells. It has been proposed as a useful target for tumor-vaccine strategies and a novel marker to define tumor subsets and predict drug response. This study aimed to investigate the expression of Sp17 in endometrial and cervical cancer specimens, its possible correlation with the pathological characteristics, and its value in the diagnosis and immunotherapy of the related cancers. METHODS: The monoclonal antibodies against human Sp17 were produced as reagents for the analysis and immunohistochemistry was used to study two major kinds of paraffin-embedded gynecological cancer specimens, including 50 cases of endometrial cancer (44 adenous and 6 adenosquamous) and 31 cases of cervical cancer (15 adenous and 16 squamous). Normal peripheral endometrial and cervical tissues were used as controls. RESULTS: Sp17 was found in 66% (33/50) of the patients with endometrial cancer and 61% (19/31) of those with cervical cancer. Its expression was found in a heterogeneous pattern in the cancer tissues. The expression was not correlated with the histological subtype and grade of malignancy, but the staining patterns were different in endometrial and cervical cancers. The hyperplastic glands were positive for Sp17 in the normal peripheral endometrial and cervical tissues in 10% (8/81) of the patients. CONCLUSIONS: Sp17 is highly expressed in human endometrial and cervical cancers in a heterogeneous pattern. Although the expression frequency of Sp17 is not correlated with the histological subtype, the staining pattern may help to define endometrial and cervical cancers. Sp17 targeted immunotherapy of tumors needs more accurate validation.

[Biological activity assays and cellular imaging of anti-human sperm protein 17 immunomagnetic nanoparticles].

AIM: To prepare anti-Sperm protein 17 (Sp17) immunomagnetic nanoparticles (IMNPs), and make foundation for target diagnosis of ovarian cancer by magnetic resonance imaging. METHODS: The anti-human Sp17 IMNPs were prepared by grafting anti-Sp17 antibodies on the surface of chitosan-coated magnetic nanoparticles (MNPs) using the linker of EDC/NHS (1-ethyl-3-[3-dimethylaminopropyl]carbodiimide/N-hydroxysuccinimide). The morphology and properties of the nanoparticles were characterized by transmission electronic microscopy (TEM), the conjugation of the antibodies was evaluated by native-polyacrylamide gel electrophoresis, the immunologic activity of IMNPs was evaluated by enzyme linked immunosorbent assay (ELISA). A set of in vitro magnetic resonance imaging (MRI) experiments were performed after incubated the IMNPs with human Sp17 gene transfected ovarian cancer HO-8910 cells. RESULTS: We had successfully grafted the MNPs with anti-Sp17 antibody and the IMNPs kept good bioactivity. The MRI showed that the IMNPs were targeted successfully to the positive cells, and no obviously non-specific adsorption was observed. CONCLUSION: The anti-Sp17 IMNPs with good specificity can used for further study of ovarian cancer target therapy.

Overexpression of human sperm protein 17 increases migration and decreases the chemosensitivity of human epithelial ovarian cancer cells.

BACKGROUND: Most deaths from ovarian cancer are due to metastases that are resistant to conventional therapies. But the factors that regulate the metastatic process and chemoresistance of ovarian cancer are poorly understood. In the current study, we investigated the aberrant expression of human sperm protein 17 (HSp17) in human epithelial ovarian cancer cells and tried to analyze its influences on the cell behaviors like migration and chemoresistance. METHODS: Immunohistochemistry and immunocytochemistry were used to identify HSp17 in paraffin embedded ovarian malignant tumor specimens and peritoneal metastatic malignant cells. Then we examined the effect of HSp17 overexpression on the proliferation, migration, and chemoresistance of ovarian cancer cells to carboplatin and cisplatin in a human ovarian carcinoma cell line, HO8910. RESULTS: We found that HSp17 was aberrantly expressed in 43% (30/70) of the patients with primary epithelial ovarian carcinomas, and in all of the metastatic cancer cells of ascites from 8 patients. The Sp17 expression was also detected in the metastatic lesions the same as in ovarian lesions. None of the 7 non-epithelial tumors primarily developed in the ovaries was immunopositive for HSp17. Overexpression of HSp17 increased the migration but decreased the chemosensitivity of ovarian carcinoma cells to carboplatin and cisplatin. CONCLUSION: HSp17 is aberrantly expressed in a significant proportion of epithelial ovarian carcinomas. Our results strongly suggest that HSp17 plays a role in metastatic disease and resistance of epithelial ovarian carcinoma to chemotherapy.

[Aberrant expression of sperm protein 17 enhances migration of ovarian cancer cell line HO-8910].

OBJECTIVE: To explore the effects of aberrant expression of sperm protein 17 (Sp17) on the migration of the ovarian cancer cell line HO-8910. METHODS: The recombinant plasmid pEGFP-Sp17 containing Sp17 and enhanced green fluorescent protein gene was transfected into the human ovarian cancer cell line HO-8910 with Lipofectamine 2000. The expression of Sp17 was examined by RT-PCR and Western blot, and the cell migratory capability detected by Transwell chamber assays. RESULTS: Sp17 was expressed as a fusion protein with EGFP after transfected. There was a significant difference in the migratory cell number of the transfected and the control cells (156.6 +/- 14.9/HP vs 39.3 +/- 8.53/HP, P < 0.05). CONCLUSION: The aberrant expression of Sp17 greatly enhances the migration of ovarian cancer cells.

[Preparation and characterization of the monoclonal antibody against human sperm protein 17].

AIM: To prepare and characterize the monoclonal antibody (mAb) against sperm protein 17 (Sp17). METHODS: Human Sp17 cDNA was cloned and recombinant Sp17 protein was expressed as a fusion protein with an N-terminal 6-His tag. The purified recombinant Sp17 protein was used to immunize BALB/c mice for preparing mAb. mAb-produced hybridoma cells were screened by ELISA and the specificity of mAb was analyzed by immunohistochemical staining and blocking test. RESULTS: Two hybridoma cells (3C12 and 3D6) secreting mAb against Sp17 were developed. The isotypes of these two mAbs, 3C12 and 3D6, were IgG(1) and IgM, respectively. ELISA detection showed that titers of mAbs, 3C12 and 3D6, were 1:64, 1:32 in cultured supernatant and 1:1 x 10(5), 1:5 x 10(4) in ascites, respectively. The results of immunohistochemical staining and blocking test indicated that 2 mAb specifically bound to Sp17 in human and rat testis and human ejaculated spermatozoa. Anti-Sp17 mAb also detected Sp17 in ovarian cancer. CONCLUSION: The successful preparation of anti-Sp17 mAb will be useful for assessing the native distribution and aberrant expression of Sp17 protein.

[Isolation of differentially expressed cDNA sequences in human gastric carcinoma by cDNA microarray].

BACKGROUND & OBJECTIVE: Some gastric carcinoma-related genes haven't been identified yet. The study was designed to isolate and identify differentially expressed cDNA sequences in gastric carcinoma, and further clone gastric carcinoma-related genes. METHODS: The differences of gene expression profile between 30 gastric carcinoma tissues and their adjacent normal tissues were analyzed by cDNA microarray which representing about 4 892 cDNA sequences, the differentially expressed cDNA sequences were analyzed by bioinformatics, and selected cDNA sequences were confirmed by reverse transcripase-polymerase chain reaction (RT-PCR). RESULTS: A total of 33 differentially expressed cDNA sequences were identified in gastric carcinoma, among which 18 up-regulated in gastric carcinoma,while 15 down-regulated. MDSCBC11 clone,represented a novel gene, located in chromosome band 1p35-36, and significantly down-regulated in 13 of 30 (43%) gastric carcinomas. CONCLUSIONS: Some gastric carcinoma-related cDNA sequences have been identified,they might be involved in pathogenesis of gastric carcinoma. This study provides a useful clue for further clone gastric carcinoma-related genes.