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Objective(s): SLC39A6 (solute carrier family 39) or LIV-1, is a zinc-transporter protein associated with estrogen-positive breast cancer and its metastatic spread. Significantly there is a direct relation between high zinc intake and unregulated cell proliferation and cancers. Blocking SLC39A6 protein may result in reduced metastasis and proliferation in many malignant tumors. This study aimed to develop an anti-SLC39A6 nanobody that is able to detect and block the SLC39A6 protein on the surface of cancerous cells. Materials and Methods: The recombinant SLC39A6 was expressed and used for camel immunization. The VHH library was constructed and screened for SLC39A6-specific nanobody. Then, the strength of nanobody in SLC39A6 detection was evaluated by Western blotting and flow cytometry. Results: We showed the ability of SLC39A6 specific Nanobody (C3) to detect SLC39A6 by Western blotting and flow cytometry. Furthermore, the C3 nanobody potently inhibits cell proliferation in MTT assay. Conclusion: These data show the potential of SLC39A6-specific nanobody for the blockade of zinc transporter protein and provide a basis for the development of novel cancer therapeutics. [ABSTRACT FROM AUTHOR]

Objective(s): Cytotoxic T-lymphocyte-associated protein-4 (CTLA-4) is the most important human immune checkpointthat modulates T cells activity and brings about immune-homeostasis. Accordingly, checkpoint inhibitor cancer therapy has been approved as a growing method to block over-expressed immune checkpoints, such as CTLA-4 receptors. Considering the competitive characteristics of single-domain antibodies with monoclonal antibodies, we tried to develop a camelid Nanobody against human CTLA-4. Materials and Methods: We have constructed the VHH gene library by using immunized-camel peripheral blood mononuclear cells and carrying out the Nested-PCR technique. VHH-library was screened by phage display technique and specific nanobodies against CTLA-4 protein were selected and amplified with bio-panning steps. Stronger binders were screened by Periplasmic Extract-ELISA, followed by estimating the complexity of the library. Specific anti-CTLA-4 Nanobody and 3hCTL55, with longer CDR3 and a higher binding rate, were selected for more assays. Results: Results revealed the existence of two different clones in the library with 108 binders. In comparison with seven different antigens, using the ELISA technique confirmed the specificity of Nanobody 3hCTL55 against human CTLA-4 antigen. We calculated Nanobody 3hCTL55 affinity for human CTLA-4 antigen at 50x10-9 M, approximately. Performing western blot and Flow-cytometry techniques showed that Nanobody 3hCTL5 5 was able to specifically detect and attach both commercial human CTLA-4 protein and human CTLA-4 antigen on the cell surface and in the cell lysate. CONCLUSION: Taken together, this developed camelid-specific anti-CTLA-4 Nanobody 3hCTL5 5, selected from a high-quality immune library by phage display technique, may be effective for further study about cancer diagnosis and cancer-therapy purposes [ABSTRACT FROM AUTHOR]

Objective(s): This study aims at exploring cytotoxic activity of different peptides derived from VSVG protein against MCF-7 and MDA-MB-231 breast cancer cell lines and human embryonic kidney normal cell (HEK 293). Materials and Methods: The ANTICP web server was used to predict anticancer peptides. The cytotoxic activity of peptides with high score (P26, P7) and low score (P19) was examined by MTT and DNA fragmentation assays. Results: The results obtained from ANTICP web server demonstrated that 4 out of 48 peptides (P26, P7, P10, and P16) had anticancer activity. P26 and P7 peptides of these 4 peptides were detected to have high cytotoxic activity against MCF-7 cells with CC50 values of 98,280 μg/ml and MDA-MB231 cells with CC50 100,550 μg/ml, respectively. In addition, the results showed that amino acid residues of these 4 peptides were located near fusion domain. Conclusion: The results confirmed that P26 and P7 peptides might induce membrane damage and initiate apoptosis. The present study suggested that P26 and P7 peptides could be appropriate candidates for further studies as cytotoxic agents and modifications in the residue at positions 70-280 might potentially produce a more efficient VSVG protein in gene therapy. [ABSTRACT FROM AUTHOR]