A growing body of work implicates chemokines and their receptors in the progression of various types of cancer, including breast cancer. However, as potent chemotactic factors for leukocytes, chemokines also have the potential to enhance anti-cancer immunity. Evidence suggests that the chemokine CXCL12 and its receptors may be important in a number of aspects of breast cancer progression and site-specific metastasis. Another chemokine, CXCL16, has been identified as a specific chemotactic factor for Type Ipolarised T lymphocytes, which are major effectors of cell-mediated immunity and hence efficacious anti-tumour immune responses. The aim of this study, therefore, was to further elucidate the roles of CXCL12 and CXCL16 in breast cancer development and metastasis. To achieve this, wild-type CXCL12 and CXCL16 and antagonists of CXCL12 and CXCL16 activity, CXCL12[subscript](P2G) and CXCL16[subscript](9-220) respectively, were overexpressed in the 4T1.2 mouse model of breast carcinoma. Overexpression of wild-type CXCL12 potently inhibited both primary tumour growth and metastasis in this model. This was attributed to the induction of an anti-tumour response dependent, in part, on T cells, interferon-g and the cytotoxic mediators perforin and TRAIL. This response was characterised by increased numbers of CD11c⁺ cells in the tumour-draining lymph nodes and enhanced cytolytic activity of lymph node-derived effector cells against tumour cells. Unexpectedly, CXCL12[subscript](P2G) inhibited metastasis of tumour cells to the lungs of tumour-bearing mice, without affecting primary tumour growth. Intravenous injection of tumour cells revealed that CXCL12[subscript](P2G) expression could block metastatic steps occurring post tumour cell escape from the primary tumour, though a role for CXCL12([subscript](P2G) at earlier metastatic steps could not be ruled out. Further work is needed to clarify the precise stages of metastasis at which CXCL12[subscript](P2G) exerts its effects. No obvious effects on primary breast tumour growth were observed when CXCL16 or CXCL16([subscript](9-220) were overexpressed in tumour cells. Interestingly, CXCL16[subscript](9-220) expression inhibited experimental metastasis but not spontaneous metastasis. The findings of this study begin to shed light on the roles of CXCL12 and CXCL16 in breast cancer progression and also highlight the potential therapeutic applications of CXCL12, CXCL16 and/or their antagonists in the treatment of breast cancer and breast cancer metastasis. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1297662 / Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Science, 2007

A growing body of work implicates chemokines and their receptors in the progression of various types of cancer, including breast cancer. However, as potent chemotactic factors for leukocytes, chemokines also have the potential to enhance anti-cancer immunity. Evidence suggests that the chemokine CXCL12 and its receptors may be important in a number of aspects of breast cancer progression and site-specific metastasis. Another chemokine, CXCL16, has been identified as a specific chemotactic factor for Type Ipolarised T lymphocytes, which are major effectors of cell-mediated immunity and hence efficacious anti-tumour immune responses. The aim of this study, therefore, was to further elucidate the roles of CXCL12 and CXCL16 in breast cancer development and metastasis. To achieve this, wild-type CXCL12 and CXCL16 and antagonists of CXCL12 and CXCL16 activity, CXCL12[subscript](P2G) and CXCL16[subscript](9-220) respectively, were overexpressed in the 4T1.2 mouse model of breast carcinoma. Overexpression of wild-type CXCL12 potently inhibited both primary tumour growth and metastasis in this model. This was attributed to the induction of an anti-tumour response dependent, in part, on T cells, interferon-g and the cytotoxic mediators perforin and TRAIL. This response was characterised by increased numbers of CD11c⁺ cells in the tumour-draining lymph nodes and enhanced cytolytic activity of lymph node-derived effector cells against tumour cells. Unexpectedly, CXCL12[subscript](P2G) inhibited metastasis of tumour cells to the lungs of tumour-bearing mice, without affecting primary tumour growth. Intravenous injection of tumour cells revealed that CXCL12[subscript](P2G) expression could block metastatic steps occurring post tumour cell escape from the primary tumour, though a role for CXCL12([subscript](P2G) at earlier metastatic steps could not be ruled out. Further work is needed to clarify the precise stages of metastasis at which CXCL12[subscript](P2G) exerts its effects. No obvious effects on primary breast tumour growth were observed when CXCL16 or CXCL16([subscript](9-220) were overexpressed in tumour cells. Interestingly, CXCL16[subscript](9-220) expression inhibited experimental metastasis but not spontaneous metastasis. The findings of this study begin to shed light on the roles of CXCL12 and CXCL16 in breast cancer progression and also highlight the potential therapeutic applications of CXCL12, CXCL16 and/or their antagonists in the treatment of breast cancer and breast cancer metastasis. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1297662 / Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Science, 2007

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第21632号 / 医博第4438号 / 新制||医||1034(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 生田 宏一, 教授 上本 伸二, 教授 竹内 理 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Equine arteritis virus (EAV) has a global impact on the equine industry being the causative agent of equine viral arteritis (EVA), a reproductive, respiratory, and systemic disease of equids. A distinctive feature of EAV infection is that it establishes long-term persistent infection in the reproductive tract of stallions and is continuously shed in the semen (carrier state). Recent studies showed that long-term persistence is associated with a specific allele of the CXCL16 gene (CXCL16S). However, the cellular and molecular mechanisms underlying the establishment and maintenance of persistent infection are yet to be determined. The studies were undertaken herein unequivocally demonstrated that the ampulla is the main EAV tissue reservoir rather than immunologically privileged tissues (i.e., testes) and that EAV has specific tropism for stromal cells and CD8+ T and CD21+ B lymphocytes but not glandular epithelium in the reproductive tract. Furthermore, persistent EAV infection is associated with a significant humoral, mucosal antibody and inflammatory response at the site of persistence, characterized by induction of high levels of neutralizing antibodies (IgG1), mucosal anti-EAV-specific IgA, IgG1, IgG3/5, and IgG4/7 with variable neutralizing efficacy; and moderate, multifocal lymphoplasmacytic ampullitis, with significant infiltration of T lymphocytes (mainly CD8+ and low numbers of FOXP3+ lymphocytes), CD21+ B lymphocytes, diverse Ig-secreting plasma cells, and Iba-1+ and CD83+ tissue macrophages/dendritic cells. Moreover, EAV long-term persistent infection is associated with a CD8+ T lymphocyte transcriptional profile with upregulation of T-cell exhaustion-related transcripts and homing chemokines/chemokine receptors (CXCL9-11/CXCR3 and CXCL16/CXCR6), orchestrated by a specific subset of transcription factors (EOMES, PRDM1, BATF, NFATC2, STAT1, IRF1, TBX21), which are associated with the presence of the susceptibility allele (CXCL16S). Finally, these studies have determined that long-term EAV persistence is associated with the downregulation of a specific seminal exosome-associated miRNA (eca-mir-128) along with an enhanced expression of CXCL16 in the reproductive tract, a putative target of eca-mir-128. These findings provide evidence that this miRNA plays a crucial role in the regulation of the CXCL16/CXCR6 axis in the reproductive tract of persistently infected stallions, a chemokine axis strongly implicated in EAV persistence. The findings presented herein suggest that complex host-pathogen interactions shape the outcome of EAV infection in the stallion and that EAV employs complex immune evasion mechanisms favoring persistence in the reproductive tract. Further studies to identify specific mechanisms mediating the modulation of the CXCL16/CXCR6 axis and viral immune evasion in the reproductive tract of the EAV long-term carrier stallion are warranted.