Biopharmaceutics

Thiadiazoles can be considered as analogs of pyrimidines because of the well
known analogy between a -CH=CH- group in benzenoid hydrocarbons and bivalent
sulfur, -S-, in aromatic heterocycles. Therefore, 5-amino-2H-1 ,2,4-thiadiazole-3-one and
5-amino-3H-1 ,3,4-thiadiazole-2-one are the analogs of cytosine. In our first project, the
preparation of six thiadiazole nucleoside analogs is reported: 5-diacetylamino-1 ,2,4-
thiadiazol-3-one (1), 5-amino-2-(tetrahydrofuran-2-yl)-1 ,2,4-thiadiazol-3-one (2), 5-
amino-3-((2' -hydroxyethoxy)methyl)-1 ,3,4-thiadiazol-2-one (3), 5-amino-3-( 4' -hydroxy-
2' -hydroxyrnethyl-butyl)-1 ,3,4-thiadiazole-2-thione ( 4), (R)-5-am ino-3-(2' ,3' -
dihydroxypropyl)-1 ,3,4-thiadiazole-2-thione (5), and (S)-5-amino-3-(2' ,3 ' -
dihydroxypropyl )-1 ,3,4-thiadiazole-2-thione (6). (R)-5-amino-3-(2' ,3' -dihydroxypropyl)-1,3,4-thiadiazole-2-thione (5) and (S)-5-amino-3-(2' ,3' -dihydroxypropyl)-1 ,3,4-
thiadiazole-2-thione (6) are stereoisomers. Their racemic mixture 7 was also prepared and
tested. The synthesis, characterization, and properties of these new synthesized
thiadiazole derivatives are discussed. A dimerization of 5-amino-3H-1 ,3 ,4-thiadiazole-2-
thione (18) to produce di-(5-amino-1 ,3,4-thiadiazol-2-yl) disulfide (23) by sodium nitrite
with either acetic acid or stannic chloride is also reported. Preliminary results indicate
that 3 and 23 possess antimicrobial activity. In the second project, the synthesis of three series of bis-aminochloropyrimidine
derivatives with different types of linkers as potential DNA intercalators is described.
The first series are aminochloropyrimidines bridged by polyrnethylene chain linkers with
various lengths. The second series are bridged by polyether linkers to lower the
lipophilicity. The third series are bridged by linkers containing benzene rings to limit the
flexibility. The spectral data and other physical properties of the new compounds are
discussed. The preliminary screening results indicate that many new synthesized bisintercalators
are biologically active. The relationship between bioactivity and structure is
discussed as well.

Metastasis is the primary cause of mortality in women with breast cancer. Recently, elevated serum levels of a glycoprotein known as chitinase-3 likeprotein- 1 (CHI3L1) has been correlated with poor prognosis and shorter survival of patients with cancer and inflammatory diseases. The biological and physiological functions of CHI3L1 in tumor progression have not yet been elucidated. In this document, we describe the role of CHI3L1 in tumor growth and metastasis and its relationship with inflammation.
Using well-established models of breast cancer, we show that CHI3L1 is increased in the serum of tumor bearing mice. We found that CHI3L1 levels are increased at both the “pre-metastatic” and “metastatic stage” and that tumor cells, splenic, alveolar and interstitial macrophages; and myeloid derived population produce CHI3L1. Furthermore, we demonstrated that CHI3L1 has an inhibitory role on the expression of interferon-gamma (IFN γ) by T cells, while enhancing the production of pro-inflammatory mediators by macrophages such as Cchemokine ligand 2 (CCL2/MCP-1), Chemokine CX motif ligand 2 (CXCL2/IL-8) and matrix metalloproteinase-9 (MMP-9), all of which promote tumor growth and metastasis. We demonstrated that in vivo treatment of tumor-bearing mice with chitin microparticles, a TH1 adjuvant and a substrate for CHI3L1, promoted immune effector functions with increased production of IFN-γ but decreased CCL2/MCP-1, CXCL2/IL-8 and MMP-9 expression by splenic and pulmonary macrophages. Significantly, in vivo administration of chitin microparticles decreased tumor growth and pulmonary metastasis in mammary tumor bearing mice. These results suggest that CHI3L1 may play a role in tumor progression. Inflammation plays a pivotal role during tumor progression and metastasis by promoting the production of pro-inflammatory molecules such as CHI3L1. However, little is known about how CHI3L1 expression can affect secondary sites to enhance metastasis. In these studies, we demonstrated that CHI3L1 alters the cellular composition and inflammatory mediators that aid in the establishment of a metastatic niche for the support of infiltrating tumor cells leading to accelerated tumor progression. Since previous studies showed that CHI3L1 modulates inflammation, we determined the role of CHI3L1 in the context of pre-existing inflammation and metastasis. We found that CHI3L1 deficient mice with preexisting inflammation had decreased pro-inflammatory mediators, and significant reduction in tumor volume and metastasis compared to wild type controls. Preexisting inflammation and CHI3L1 may be driving the establishment of a premetastatic milieu in the lungs and aiding in the establishment of metastasis. Understanding the role of CHI3L1 in inflammation during tumor progression could result in the design of targeted therapies for breast cancer patients.

Carbohydrate recognition is one of the most sophisticated recognition processes in biological
systems, mediating many important aspects of cell-cell recognition, such as inflammation, cell
differentiation, and metastasis. Consequently, lectin-glycan interactions have been intensively
studied in order to mimic their actions for potential bioanalytical and biomedical applications.
Galectins, a class of ß-galactoside-specific animal lectins, have been strongly implicated in
inflammation and cancer. Galectin-3 is involved in carbohydrate-mediated metastatic cell
heterotypic and homotypic adhesion via interaction with Thomsen-Friedenreich (TF) antigen on
cancer-associated MUC1. However, the precise mechanism by which galectin-3 recognizes TF
antigen is poorly understood. Our thermodynamic studies have shown that the presentation of the
carbohydrate ligand by MUC1-based peptide scaffolds can have a major impact on recognition,
and may facilitate the design of more potent and specific galectin-3 inhibitors that can be used as
novel chemical tools in dissecting the precise role of galectin-3 in cancer and inflammatory
diseases. Another lectin, odorranalectin (OL), has been recently identified from Odorrana grahami
skin secretions as the smallest cyclic peptide lectin, has a particular selectivity for L-fucose and
very low toxicity and immunogenicity, rendering OL an excellent candidate for drug delivery to
targeted sites, such as: (1) tumor-associated fucosylated antigens implicated in the pathogenesis
of several cancers, for overcoming the nonspecificity of most anticancer agents; (2) the olfactory epithelium of nasal mucosa for enhanced delivery of peptide-based drugs to the brain.