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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

APOPTIN AND ITS DERIVATIVES AS MOLECULAR CLUES TOWARDS THE DEVELOPMENT OF NOVEL TYROSINE KINASE INHIBITORS

Panigrahi, Soumya 03 September 2009 (has links)
The non-receptor tyrosine kinase activity of fusion gene BCR-ABL derived oncoproteins is the key factor responsible for development and progress of Philadelphia positive (Ph+) chronic myeloid leukemia (CML). In the search for a superior and novel peptide-based inhibitor of Bcr-Abl, here I investigated a naturally occurring molecule, called apoptin. Apoptin is a 13.6 kDa protein derived from chicken anemia virus (CAV) and known to induce apoptosis in a wide range of transformed but not in primary cells. Apoptin is a protein without any reported structural and/or functional homolog and is an interesting candidate to initiate protein-protein interactions and subsequent downstream effects. Initially by an array-based analysis I found that apoptin interacts with the SH3 domain of Abl. By high stringency pull-down and co-immunoprecipitation assays the apoptin and Bcr-Abl interaction was further confirmed. Subsequently, a set of apoptin and Bcr-Abl deletion mutants were used to map this interaction precisely that mainly occurred between a proline rich domain of apoptin and the SH3 domain of Bcr-Abl. I further investigated the role of apoptin on Bcr-Abl. Apoptin was able to modify the phosphorylation of a series of targets (e.g. CrkL, STAT5, c-Myc) downstream of Bcr-Abl kinase. In addition, I used computational algorhythms for protein modeling to study the 3D structure of apoptin and it’s docking with Bcr-Abl at the molecular level. In controlled studies using the 2-pheny-laminopyrimidine derived specific tyrosine kinase inhibitor Imatinib® I found that apoptin has comparable effects on CML cells, suggesting that the interacting segment of the apoptin molecule acts as an adaptor and negatively regulates the Bcr-Abl kinase by deactivating many cell proliferation and anti-apoptotic pathways in CML cells. Briefly, this work provides important insights towards the development of peptide based tyrosine kinase inhibitors as new anti-cancer agents.
2

APOPTIN AND ITS DERIVATIVES AS MOLECULAR CLUES TOWARDS THE DEVELOPMENT OF NOVEL TYROSINE KINASE INHIBITORS

Panigrahi, Soumya 03 September 2009 (has links)
The non-receptor tyrosine kinase activity of fusion gene BCR-ABL derived oncoproteins is the key factor responsible for development and progress of Philadelphia positive (Ph+) chronic myeloid leukemia (CML). In the search for a superior and novel peptide-based inhibitor of Bcr-Abl, here I investigated a naturally occurring molecule, called apoptin. Apoptin is a 13.6 kDa protein derived from chicken anemia virus (CAV) and known to induce apoptosis in a wide range of transformed but not in primary cells. Apoptin is a protein without any reported structural and/or functional homolog and is an interesting candidate to initiate protein-protein interactions and subsequent downstream effects. Initially by an array-based analysis I found that apoptin interacts with the SH3 domain of Abl. By high stringency pull-down and co-immunoprecipitation assays the apoptin and Bcr-Abl interaction was further confirmed. Subsequently, a set of apoptin and Bcr-Abl deletion mutants were used to map this interaction precisely that mainly occurred between a proline rich domain of apoptin and the SH3 domain of Bcr-Abl. I further investigated the role of apoptin on Bcr-Abl. Apoptin was able to modify the phosphorylation of a series of targets (e.g. CrkL, STAT5, c-Myc) downstream of Bcr-Abl kinase. In addition, I used computational algorhythms for protein modeling to study the 3D structure of apoptin and it’s docking with Bcr-Abl at the molecular level. In controlled studies using the 2-pheny-laminopyrimidine derived specific tyrosine kinase inhibitor Imatinib® I found that apoptin has comparable effects on CML cells, suggesting that the interacting segment of the apoptin molecule acts as an adaptor and negatively regulates the Bcr-Abl kinase by deactivating many cell proliferation and anti-apoptotic pathways in CML cells. Briefly, this work provides important insights towards the development of peptide based tyrosine kinase inhibitors as new anti-cancer agents.
3

Development of strategies to enhance protein transduction efficiency for cancer therapy

Su, Yu-wei 14 February 2005 (has links)
Protein transduction domains (PTDs), such as TAT from human immunodeficiency virus (HIV) or VP22 from herpes-simplex-virus-1, have been shown to deliver a myriad of molecules, including synthetic small molecules, peptides and proteins in vivo and in vitro. The protein transduction processes mediated by TAT or VP22 are highly efficient and occur in many types of cells with low toxicity. The anti-tumor proteins to be investigated are abrin A chain (ABR-A) and Apoptin. ABR-A is the toxophoric subunit of plant toxin abrin from the seeds of Abrus precatoriusa. ABR-A is a potent inhibitor of translation, but not toxic to cells due to its lack of the cell-binding B chain. Apoptin is a protein derived from chicken anemia virus and has been proved to be selectively cytotoxic to various tumor cells but not to normal cells. The tumor-specific activity of Apoptin is correlated with its nuclear localization in tumor. In this study, we employed VP22 PTDs to promote the entry of natural toxins, such as ABR-A or Apoptin, into tumor cells, thereby to enhance their anti-tumor effects. We generated and characterized green fluorescent protein (GFP)-, hemagglutini (HA)-, and VP22-fused expression constructs for ABR-A and Apoptin, to evaluate the gene delivery effect of ABR-A/Apoptin genes in non-transformed NIH3T3 cells and tumor cells, including Hela and A375 melanoma cells. Gene delivery of ABR-A led to growth inhibition by 50~70% in transformed and non-transformed cells. In contrast, Apoptin gene delivery exhibited cytotoxicity only in tumor cells. The cytotoxicity of ABR-A and Apoptin gene delivery was enhanced when fused with VP-22. Furthermore, the depletion of APAP1 reduced the cytotoxic effect of Apoptin gene delivery. In the future, the anti-tumor effect of these novel PTD-toxin vectors will be explored in cell culture as well as animal model. We hope these studies will open a new avenue for cancer therapy.

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