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Melanoma is a malignant and metastatic form of skin cancer, which is not diagnosed in early stages of the disease. Nowadays, immunotherapy is changing the treatment landscape for metastatic melanoma. Placenta-specific1 (PLAC1) is a cancer-testis-placenta (CTP) antigen with differential expression in melanoma tissues. Here, we evaluated the potential of plac1 to induce anti-cancer immune responses as well as to prevent cancer development in a mouse model of melanoma.Two proteins containing full extracellular domain (ED) of mouse plac1+KDEL3 and full ED of mouse plac1+ tetanus toxin P2 and P30+ pan DR epitope (PADRE) ​+ ​KDEL3 were produced and injected in mice to evaluate their capacity to induce anti-cancer immune responses as well as their potential to prevent melanoma development. Induction of plac1-specific humoral and cellular responses as well as tumor-associated parameters were tested in a series of 36 mice.Sera of mice immunized with ED ​+ ​P2P30+PADRE ​+ ​KDEL3 contained antibodies able to react with surface plac1 in B16F10 ​cells. Both proteins induced proliferative cellular immune responses against B16F10 ​cells and plac1-specific cytotoxic T cells (CTL) and CD107a ​+ ​CTL responses, which was higher in mice immunized with ED ​+ ​P2P30+PADRE ​+ ​KDEL3. Splenocytes of mice vaccinated with ED ​+ ​P2P30+PADRE ​+ ​KDEL3 exerted a significant cytotoxicity against B16F10 ​cells. Vaccination with ED ​+ ​P2P30+PADRE ​+ ​KDEL3 significantly delayed B16F10-induced tumor onset, reduced tumor growth, and increased survival. Tumors induced by B16F10 expressed plac1 in vivo.Our results pave the way for development of effective melanoma preventive vaccine in humans, although further studies are needed.

Background: Placenta-specific 1 (PLAC1) is one of the recently-discovered Cancer-Testis-Placenta (CTP) antigen with restricted normal tissue and ectopic expression in a wide range of cancer cells from different histological origins. The production of recombinant human PLAC1 has already been optimized; however, no study has been reported so far on the production and purification of mouse plac1. In this study, mouse plac1 expression and purification was optimized in a prokaryotic system and the effects of the generated proteins on inducing humoral responses in mice were investigated. Methods: A fusion protein containing full extracellular domain of mouse plac1, immunostimulatory peptides, tetanus toxin P2P30 and PADRE and KDEL3 signal (main plac1), and the same fragment without immunostimulatory peptides (control plac1) was produced. To optimize production and purification steps, different parameters including bacterial strain, cultivation temperature, cultivation time, IPTG concentration, culture medium, and also different buffers for purification of the recombinant proteins were tested. After confirming the identity of recombinant plac1 proteins with Western Blotting (WB) and ELISA assays, these proteins were subcutaneously injected in mice with Freund's adjuvant and the anti-plac1 antibody response was detected by ELISA. Results: The optimal expression level of main and control plac1 was obtained in BL21 (DE3) and TB culture medium in the presence of 0.25 mM IPTG after 24 hr of induction at 15°C. The buffer containing 2% sarkosyl produced higher yield and purity. Our results showed specific reactivity of anti-human recombinant plac1 polyclonal antibody with both main and control plac1 recombinant proteins in WB and ELISA analysis. Both proteins induced humoral responses in mice; however, anti-plac1 antibody titer was significantly higher in sera of mice immunized with main compared to control plac1. Conclusion: In this study, an optimized protocol for production and purification of mouse plac1 was reported and it was shown that insertion of immunostimulatory peptides in gene construct could efficiently enhance humoral immune responses against mouse plac1, which could potentially augment cellular immune responses against plac1 leading to more effective anti-cancer responses.

Background: Oral Squamous Cell Carcinoma (OSCC) is among the ten most common cancers worldwide. Hypermethylation of CpG sites in the promoter region and subse-quent down-regulation of a tumor suppressor gene, TGM-3 has been proposed to be linked to different types of human cancers including OSCC. In this study, methylation sta-tus of CpG sites in the promoter region of TGM-3 has been evaluated in a cohort of pa-tients with OSCC compared to normal controls. Methods: Forty fresh tissue samples were obtained from newly diagnosed OSCC patients and normal individuals referred to dentistry clinic for tooth extraction. DNA was extract-ed, bisulfite conversion was performed and it was subjected to PCR using bisulfite-sequencing PCR (BSP) primers. Prepared samples were sequenced on a DNA analyzer with both forward and reverse primers of the region of interest. The peak height values of cytosine and thymine were calculated and methylation levels for each CpG site within the DNA sequence was quantified. Results: Quantitative DNA methylation analyses in CpG islands revealed that it was sig-nificantly higher in OSCC patients compared to controls. DNA methylation at CpG1/CpG3/CpG5 (p=0.004-0.01) and CpG1/CpG3 (p=0.001-0.019) sites was associated with tumor stage and grade, respectively. Male OSCC patients had higher methylation rate at CpG3 (p=0.032), while smoker patients showed higher methylation rate at CpG6 (p=0.045). Conclusion: These results manifested the contribution of DNA methylation of TGM-3 in OSCC and its potential association with clinico-pathologic parameters in OSCC.

Introduction Placenta is a complex organ that plays a significant role in the maintenance of pregnancy health. It is a dynamic organ that undergoes dramatic changes in growth and development at different stages of gestation. In the first-trimester, the conceptus develops in a low oxygen environment that favors organogenesis in the embryo and cell proliferation and angiogenesis in the placenta; later in pregnancy, higher oxygen concentration is required to support the rapid growth of the fetus. This oxygen transition, which appears unique to the human placenta, must be finely tuned through successive rounds of protein signature alterations. This study compares placental proteome in normal first-trimester (FT) and term human placentas (TP). Methods Normal human first-trimester and term placental samples were collected and differentially expressed proteins were identified using two-dimensional liquid chromatography-tandem mass spectrometry. Results Despite the overall similarities, 120 proteins were differently expressed in first and term placentas. Out of these, 72 were up-regulated and 48 were down-regulated in the first when compared with the full term placentas. Twenty out of 120 differently expressed proteins were sequenced, among them seven showed increased (GRP78, PDIA3, ENOA, ECH1, PRDX4, ERP29, ECHM), eleven decreased (TRFE, ALBU, K2C1, ACTG, CSH2, PRDX2, FABP5, HBG1, FABP4, K2C8, K1C9) expression in first-trimester compared to the full-term placentas and two proteins exclusively expressed in first-trimester placentas (MESD, MYDGF). Conclusion According to Reactome and PANTHER softwares, these proteins were mostly involved in response to chemical stimulus and stress, regulation of biological quality, programmed cell death, hemostatic and catabolic processes, protein folding, cellular oxidant detoxification, coagulation and retina homeostasis. Elucidation of alteration in protein signature during placental development would provide researchers with a better understanding of the critical biological processes of placentogenesis and delineate proteins involved in regulation of placental function during development.

Here we introduce novel optical properties and accurate sensitivity of Quantum dot (QD)-based detection system for tracking the breast cancer marker, HER2. QD525 was used to detect HER2 using home-made HER2-specific monoclonal antibodies in fixed and living HER2(+) SKBR-3 cell line and breast cancer tissues. Additionally, we compared fluorescence intensity (FI), photostability and staining index (SI) of QD525 signals at different exposure times and two excitation wavelengths with those of the conventional organic dye, FITC. Labeling signals of QD525 in both fixed and living breast cancer cells and tissue preparations were found to be significantly higher than those of FITC at 460-495 nm excitation wavelengths. Interestingly, when excited at 330-385 nm, the superiority of QD525 was more highlighted with at least 4-5 fold higher FI and SI compared to FITC. Moreover, QDs exhibited exceptional photostability during continuous illumination of cancerous cells and tissues, while FITC signal faded very quickly. QDs can be used as sensitive reporters for in situ detection of tumor markers which in turn could be viewed as a novel approach for early detection of cancers. To take comprehensive advantage of QDs, it is necessary that their optimal excitation wavelength is employed.

Carcinoma antigen 125 (CA 125) is overexpressed in ovarian cancer and antibodies against it are widely employed for diagnostic purposes. The rarity of CA 125 antigenic domains and its highly glycosylated structure, however, is a problem that may prevent immunized mice from developing a diversified population of anti-CA 125 antibodies. In this study a prime-boost strategy, which potentially could augment the humoral immune responses against rare and poorly immunogenic determinants, was used for immunization of mice and monoclonal antibodies (mAbs) were produced by hybridoma technology. Reactivity of mAbs was then assessed by ELISA, western blotting, immunoprecipitation, immunohistochemistry and immunofluorescence staining of OVCAR-3 cell line. Altogether, 10 clones were produced, 3 of which had IgG isotype and the rest were IgM. Two-third of clones recognized cognate antigen in fixed and living cells and had strong immunoreactivity in IHC staining. In Western blotting, our antibodies recognized CA 125 as high molecular weight antigen mostly migrated in the 3% stacking gel. Immunoprecipitation of OVCAR-3 cell lysate by mAbs resulted in a very similar migration pattern that reconfirmed their specificities. The mAbs produced in this study are invaluable tools in diagnosis and research fields for assessment of CA 125 expression in cancerous ovarian tissues.

Monoclonal antibodies (mAbs) are essential tools for many molecular immunology investigations, epitope mapping and molecular modelling, clinical laboratory diagnostic tests and immunotherapy. Humoral immune response of immunized animals largely depends on the nature of antigen and the immunization technique. Polysaccharides and heavily-glycosylated proteins are very elusive targets incapable of mounting long-lasting, high affinity antibody responses. Carcinoma antigen 125 (CA 125), a well known tumor marker of ovarian cancer, is a mucin type antigen consisting of repetitive units of heavily glycosylated moieties which render production of mAbs very difficult.To evaluate the efficacy of heterologous antigen preparations as a way of mouse immunization in the production of anti-CA 125 mAb.Two different protocols of immunization were used for priming of NMRI mice. In the first method, mice conventionally immunized by three intraperitoneal injections of purified CA 125 and boosted by the antigen three days before fusion. In the second approach, mice were primed by three intraperitoneal injections of living CA 125 positive cells of OVCAR-3 cell line, and boosted by intravenous injection of the purified extracellular domain of CA 125. Production of mAb was performed by standard hybridoma technology and mAbs were characterized by different immunoassays.The first method failed to produce stable clones despite six time fusion. A total of ten stable clones, however, were produced in the second approach. Some of the clones were characterized and found to have excellent immunoreactivity when tested by ELISA assay, western blotting, intracellular and surface immunofluorescent staining of OVCAR-3 cell line and immunohistochemical staining of ovarian cancer tissues.Altogether the results of the present study clearly showed that heterologous antigen preparation is the method of choice for immunization when production of monoclonal antibody against highly glycosylated poorly immunogenic antigens is concerned.