Thesis (Ph. D.)--Michigan State University. Dept. of Biochemistry, 2007. / Title from PDF t.p. (viewed on Apr. 16, 2009) Includes bibliographical references. Also issued in print.

Angiogenesis by either normal or neoplastic cells involves a delicate balance of both angiogenic and angiostatic regulators. In the ovary, normal physiological angiogenesis occurs around the developing follicle and corpus luteum in response to hormonal shifts. Interestingly, carcinomas arising from the ovary are usually highly vascularized and are commonly clinically observed to produce cyst fluids or ascites which contain both angiostatic and/or angiogenic regulators. However, in contrast to normal angiogenesis, angiogenesis associated with epithelial ovarian cancer usually produces aberrant vasculature that may promote neoplastic progression. Therefore, the ovary and ovarian cancers provide models to study the mechanisms governing the strict balance of angioregulators in both normal and tumor angiogenesis. While most studies to date have focused on angiogenic regulators for normal and aberrant angiogenesis, we investigated the potential for dysregulation of angiostatic regulators to contribute to the etiology of epithelial ovarian cancer. Therefore, in this study, we examined two angiostatic regulators, angiostatin and semaphorin 3F, in epithelial ovarian cancer. Angiostatin, a cleavage product of the circulating zymogen plasminogen, was isolated from serum and urine of mice bearing a Lewis lung carcinoma and in vivo studies have demonstrated its potent angiostatic properties. Thus, we investigated the potential prognostic/diagnostic advantage of aberrant angiostatin expression with epithelial ovarian cancer. We found that urinary angiostatin, compared to other angioregulators in plasma or urine, could serve as an effective biomarker for early detection of epithelial ovarian cancer, especially when used in combination with cancer antigen 125. Additionally, urinary angiostatin correlated with both recurrent disease as well as successful tumor ablation further supporting its potential as a disease biomarker. Alternative biological functions for the axon guidance molecule, semaphorin 3F, have been reported particularly in regard to angiogenesis, tumor progression and metastasis. However, the underlying mechanisms governing semaphorin 3F regulation and dysregulation remain unclear. Therefore, we first investigated the clinical relationship between semaphorin 3F expression and epithelial ovarian cancer progression. These immunohistological studies revealed that, similar to lung cancer, semaphorin 3F expression decreased with progression supporting a tumor suppressor-like role for semaphorin 3F. Additionally, we found that calcium, an essential cellular signaling molecule, could mediate transcriptional suppression of semaphorin 3F expression in a CREB-dependent manner. Lastly, given the antagonistic relationship between semaphorin 3F and vascular endothelial growth factor, we sought to determine whether semaphorin 3F and vascular endothelial growth factor promoted opposing effects on a common downstream target. In the course of these studies we determined that telomerase is a novel molecular target of semaphorin 3F in ovarian cancer cells such that semaphorin 3F suppresses telomerase activity while vascular endothelial growth factor promotes telomerase activity. In addition, we found that the inverse relationship between semaphorin 3F and telomerase was mediated through transcriptional inhibition of the hTERT promoter by semaphorin 3F. In conclusion, this research shows that dysregulation of the angiostatic regulators, angiostatin and semaphorin 3F, may contribute to the etiology of epithelial ovarian cancer. In the future, dysregulation of these and other angiostatic regulators may be exploited for therapeutic intervention or as biomarkers for early detection which would allow women more treatment choices and hopefully, reduce the mortality associated with this insidious disease.

Acute lung injury is marked by profound neutrophil influx along with fluid accumulation that impairs lung function at the cost of high mortality (up to 40%). Neutrophils are activated and their constitutive apoptosis is inhibited during this phase in order to be competent phagocytes over the next few hours. Activated neutrophils release copious amounts of toxic mediators that cause tissue damage leading to impaired barrier function and finally, impaired lung function. Therefore, one of the critical needs is to identify molecules that regulate neutrophil migration and silence activated neutrophils to prevent exuberant tissue damage. Angiostatin is an anti-angiogenic molecule highly expressed in lavage fluid of patients with acute respiratory distress syndrome. Angiostatin has recently been shown to inhibit neutrophil infiltration in mice peritonitis. However, the role of angiostatin in modulating neutrophil physiology and lung inflammation remains unknown. I studied the role of angiostatin, an anti-angiogenic molecule, in neutrophil activation and recruitment <i>in vivo</i> and <i>in vitro</i>. Angiostatin was endocytosed only by activated neutrophils, inhibited neutrophil polarity in fMLP-activated neutrophils probably through integrin &alpha;_V&beta;₃, and inhibited MAPK signalling in LPS-activated neutrophils. Angiostatin suppressed formation of reactive oxygen species and activated caspase-3 in neutrophils in both pre-and post-LPS treatments. Finally, angiostatin reduced adhesion and emigration of neutrophils in post-capillary venules of TNF&alpha;-treated cremaster muscle. The next study was designed to investigate the role of angiostatin in acute lung injury. I used <i>E. coli</i> lipopolysaccharide induced acute lung injury mouse model to test the effects of angiostatin through analyses of bronchoalveolar lavage and lung tissues. In addition, I made novel use of synchrotron diffraction enhanced imaging of mouse lungs to assess lung area and contrast ratios over 9 hours as surrogates for lung inflammation. Subcutaneous treatment with angiostatin reduced neutrophil influx, protein accumulation, lung Gr1+ neutrophils and myeloperoxidase activity, phosphorylated p38 MAPK without affecting the levels of MIP-1&alpha;, IL-1&beta;, KC and MCP-1 in lavage and lung homogenates. Diffraction enhanced imaging showed that angiostatin causes a time-dependent improvement in lung area and lung contrast ratios that reflect improvement in lung edema. Overall, the study shows that angiostatin is a novel inhibitor of acute lung injury in mice. Moreover, DEI offers a highly useful technique in evaluating dynamics of lung inflammation and to investigate the therapeutic impact of new drugs on lung inflammation. I conclude that angiostatin is a novel inhibitor of neutrophil migration, activation and acute lung injury.

Acute lung injury is marked by profound neutrophil influx along with fluid accumulation that impairs lung function at the cost of high mortality (up to 40%). Neutrophils are activated and their constitutive apoptosis is inhibited during this phase in order to be competent phagocytes over the next few hours. Activated neutrophils release copious amounts of toxic mediators that cause tissue damage leading to impaired barrier function and finally, impaired lung function. Therefore, one of the critical needs is to identify molecules that regulate neutrophil migration and silence activated neutrophils to prevent exuberant tissue damage. Angiostatin is an anti-angiogenic molecule highly expressed in lavage fluid of patients with acute respiratory distress syndrome. Angiostatin has recently been shown to inhibit neutrophil infiltration in mice peritonitis. However, the role of angiostatin in modulating neutrophil physiology and lung inflammation remains unknown. I studied the role of angiostatin, an anti-angiogenic molecule, in neutrophil activation and recruitment <i>in vivo</i> and <i>in vitro</i>. Angiostatin was endocytosed only by activated neutrophils, inhibited neutrophil polarity in fMLP-activated neutrophils probably through integrin &alpha;_V&beta;₃, and inhibited MAPK signalling in LPS-activated neutrophils. Angiostatin suppressed formation of reactive oxygen species and activated caspase-3 in neutrophils in both pre-and post-LPS treatments. Finally, angiostatin reduced adhesion and emigration of neutrophils in post-capillary venules of TNF&alpha;-treated cremaster muscle. The next study was designed to investigate the role of angiostatin in acute lung injury. I used <i>E. coli</i> lipopolysaccharide induced acute lung injury mouse model to test the effects of angiostatin through analyses of bronchoalveolar lavage and lung tissues. In addition, I made novel use of synchrotron diffraction enhanced imaging of mouse lungs to assess lung area and contrast ratios over 9 hours as surrogates for lung inflammation. Subcutaneous treatment with angiostatin reduced neutrophil influx, protein accumulation, lung Gr1+ neutrophils and myeloperoxidase activity, phosphorylated p38 MAPK without affecting the levels of MIP-1&alpha;, IL-1&beta;, KC and MCP-1 in lavage and lung homogenates. Diffraction enhanced imaging showed that angiostatin causes a time-dependent improvement in lung area and lung contrast ratios that reflect improvement in lung edema. Overall, the study shows that angiostatin is a novel inhibitor of acute lung injury in mice. Moreover, DEI offers a highly useful technique in evaluating dynamics of lung inflammation and to investigate the therapeutic impact of new drugs on lung inflammation. I conclude that angiostatin is a novel inhibitor of neutrophil migration, activation and acute lung injury.

For the past 40 years, antiangiogenic approaches have been of major interest in the development of methods to cure and prevent cancer. Angiogenesis, the development of blood vessels from pre-existing vascularization, is essential for cancer growth and spread of metastasis through the delivery of nutrients and oxygen essential to sustain the metabolic activity of these malignant cells. Blocking access to blood will cause cancerous cells to assume a dormant state creating inactive micro-tumors innocuous to the host. Angiostatin, the internal fragment of the fibrinolytic zymogen plasminogen, has shown great potential in reducing cancer size and number of metastatic colonies in animal models. Owing to the success of these preliminary results angiostatin is currently on clinical trials. Plasminogen is known to be transferred from blood to milk during lactation. The objectives of this research were to: 1) investigate the ability of various proteases in cleaving plasminogen, both from human and bovine sources, and consequently release the angiostatin like fragment; 2) determine the anticancer activity of bovine angiostatin; 3) examine ability of the antiangiogenic fragment to survive digestion; 4) purify the fragment of interest through column chromatography. Production of angiostatin was tested through hydrolysis of plasminogen via Bacillus Polymyxa protease (or dispase I), elastase, lactic acid bacteria and Bacilli originated enzymes. Once proteases capable of angiostatin like peptide production were identified, and sequence analysis of the fragments obtained conducted to confirm that bovine angiostatin was indeed produced, ability of angiostatin, both human and bovine, in inhibiting malignant melanoma as well as colon cancer cells was evaluated in vitro. From the results obtained we can confirm that bovine angiostatin inhibitory activity on cancerous cells is similar to that observed for human angiostatin. Analysis of bovine angiostatin survival through in vitro human digestion model was also examined. Results show good possibility of angiostatin surviving digestion, even if confirmation of these results is required through further in vivo studies. Additionally, digestive enzymes such as trypsin and α-chymotrypsin showed ability in cleaving plasminogen directly to release a 25kDa fragment. Knowing that each kringle has some degree of anticancer activity it would be of interest to further study the possibility of angiostatin related fragments to be produced during milk digestion. Finally, affinity chromatography through L-lysine used to purify human angiostatin resulted to be an adequate method for bovine angiostatin purification. Preliminary results obtained from this study open a new area worth investigating to uncover the potential of using bovine angiostatin in the development of novel food products capable of cancer prevention.

Diversas doenças estão associadas com a formação de novos vasos a parti vasos pré-existentes, ou angiogênese. Dentre elas está a aterosclerose (Griffioen & Molema, 2000). Pesquisas recentes demonstram que a hipercolesterolemia, que têm um papel importante na fisiologia da aterosclerose, também pode prejudicar a ação de fatores angiogênicos (Jang et.al., 2000). A hipercolesterolemia que é decorrente de aumento de LDL no plasma ocasiona um aumento no tempo de permanência desta partícula na circulação (Yasunobu, 2001). Contudo, a LDL pode sofrer modificação na circulação, dando origem a uma subfração mais eletronegativa da LDL, a LDL (-). A LDL (-) pode prejudicar cada etapa da angiogênese, desregulando a função endotelial (Tai et. al., 2006). Em nosso estudo, vimos que apesar da LDL (-) ter estimulado a miga celular, esta partícula inibiu a formação de túbulos in vitro. A LDL (-) não foi capa afetar a angiogênese in vivo. / A large number of diseases is associated with formation of new blood vessels out of pre-existing capillaries, or angiogenesis. These diseases include the atherosclerosis (Griffioen & Molema, 2000). Resents researches demonstrate that the hypercholesterolemia, that have a important role in the physiology of the atherosclerosis, can impaired the angiogenesis (Jang et. al., 2000) . The hypercholesterolemia that is decurrente of high levels of LDL in the plasma causes an increase in the time of permanence this particle in the circulation (Yasunobu, 2001). However, the LDL can to suffer modification in the circulation, giving rise to a subfration more eletronegative from LDL, the LDL (-). The LDL (-) could impair each one of the steps of the angiogenesis, thereby dysregulating endothelial function (Tai et. al., 2006). In our study, see that despite the LDL (-) have stimulated the cell migration, this particle inhibited the Tube formation in vitro. The LDL (-) didn\'t affect the angiogenesis in vivo.

Diversas doenças estão associadas com a formação de novos vasos a parti vasos pré-existentes, ou angiogênese. Dentre elas está a aterosclerose (Griffioen & Molema, 2000). Pesquisas recentes demonstram que a hipercolesterolemia, que têm um papel importante na fisiologia da aterosclerose, também pode prejudicar a ação de fatores angiogênicos (Jang et.al., 2000). A hipercolesterolemia que é decorrente de aumento de LDL no plasma ocasiona um aumento no tempo de permanência desta partícula na circulação (Yasunobu, 2001). Contudo, a LDL pode sofrer modificação na circulação, dando origem a uma subfração mais eletronegativa da LDL, a LDL (-). A LDL (-) pode prejudicar cada etapa da angiogênese, desregulando a função endotelial (Tai et. al., 2006). Em nosso estudo, vimos que apesar da LDL (-) ter estimulado a miga celular, esta partícula inibiu a formação de túbulos in vitro. A LDL (-) não foi capa afetar a angiogênese in vivo. / A large number of diseases is associated with formation of new blood vessels out of pre-existing capillaries, or angiogenesis. These diseases include the atherosclerosis (Griffioen & Molema, 2000). Resents researches demonstrate that the hypercholesterolemia, that have a important role in the physiology of the atherosclerosis, can impaired the angiogenesis (Jang et. al., 2000) . The hypercholesterolemia that is decurrente of high levels of LDL in the plasma causes an increase in the time of permanence this particle in the circulation (Yasunobu, 2001). However, the LDL can to suffer modification in the circulation, giving rise to a subfration more eletronegative from LDL, the LDL (-). The LDL (-) could impair each one of the steps of the angiogenesis, thereby dysregulating endothelial function (Tai et. al., 2006). In our study, see that despite the LDL (-) have stimulated the cell migration, this particle inhibited the Tube formation in vitro. The LDL (-) didn\'t affect the angiogenesis in vivo.