Cancer accounts for nearly one-quarter of deaths in the United States, exceeded only by heart diseases. In 2006, there were 559,888 cancer deaths in the US. Finding effective treatments for cancer is a major challenge among researchers. In solid tumor, hypoxia increases the progression of malignancy and metastasis by promoting angiogenesis. The transcription factor HIF-1 is responsible for the regulation of cellular processes, including glycolysis and angiogenesis. Clinical evidence has determined that expression of HIF-1 is strongly associated with poor patient prognosis. Also, activation of HIF-1 contributes to malignant behavior and therapeutic resistance. In view of these observations, there is a need for anti-cancer treatments that addresses hypoxic related tumors. HIF-1 presents a viable target for inhibition of tumor growth with small molecules. Herein, we describe the design and synthesis of small molecules that inhibit the HIF-1 pathway, as well as mechanistic studies involved in the investigation of the mode of action of these compounds.

The Severe Acute Respiratory Syndrome (SARS) virus encodes several unusual RNA processing enzymes, including Nsp15, an endoribonuclease that preferentially cleaves 3? of uridylates through a Ribonuclease A-like mechanism. Crystal structures of Nsp15 confirmed that the Nsp15 active site is structurally similar to that of Ribonuclease A. These similarities and our molecular docking analysis lead us to hypothesize that previously characterized Ribonuclease A inhibitors will also inhibit the SARS-CoV Nsp15. Benzopurpurin B, C-467929, C-473872, N-36711, N-65828, N-103018 and Congo red were tested for effects on Nsp15 endoribonuclease activity. A real-time fluorescence assay revealed that the IC50 values for inhibiting Nsp15 were between 0.2 ?M and 40 ?M. Benzopurpurin B, C-473872, and Congo red are competitive inhibitors, according to kinetic studies and were demonstrated to bind SARS-CoV Nsp15 by a differential scanning fluorimetry assay. Benzopurpurin B also inhibited the Nsp15 orthologs from two other coronaviruses: mouse hepatitis virus (MHV) and infectious bronchitis virus. The three compounds reduced infectivity of MHV in L2 cells by 8 to 26 fold. The more effective drugs also caused a decrease in MHV RNA accumulation.

Throughout history, cancer has been severely plaguing mankind; the search for a cure to cancer had long been sought by scientists and still poses as one of the greatest challenges scientists have yet to overcome. Hypoxia in cells is a condition where there is little to no oxygen availability in its environment. In general, this event is detrimental since this can lead to cell necrosis or reoxygenation injuries. However, hypoxia, a prominent property of most solid tumors, activates the hypoxia-inducible factor (HIF-1) family of transcription factors that promotes angiogenesis. In this study, we describe the design and synthesis of small-molecule inhibitors of the HIF-1 pathway.

DNA lesions arise constantly in cells and are repaired by a variety of DNA repair pathways. Polynucleotide kinase 3’-phosphatase (PNKP) aids repair by phosphorylating 5’-hydroxyl DNA termini and dephosphorylating 3’-phosphate DNA termini for the completion of repair by DNA ligases. This activity is critical in vivo because DNA breaks do not usually possess ligatable termini. PNKP knockdown sensitizes cells to several DNA damaging agents, including the topoisomerase I (TOP1) inhibitor camptothecin - analogs of which are being developed into chemotherapeutic drugs - because the resolution of stalled TOP1-DNA complexes requires processing by PNKP. We hypothesize that small molecule inhibitors of PNKP could bolster the effects of radio- and chemotherapies on cancer cells. I have identified eight compounds that effectively inhibit human PNKP and, with reduced potency, T4 PNK in vitro. These compounds act by reversibly inhibiting the substrate-enzyme interaction but they do not appear to sensitize U2OS cells to camptothecin.

DNA lesions arise constantly in cells and are repaired by a variety of DNA repair pathways. Polynucleotide kinase 3’-phosphatase (PNKP) aids repair by phosphorylating 5’-hydroxyl DNA termini and dephosphorylating 3’-phosphate DNA termini for the completion of repair by DNA ligases. This activity is critical in vivo because DNA breaks do not usually possess ligatable termini. PNKP knockdown sensitizes cells to several DNA damaging agents, including the topoisomerase I (TOP1) inhibitor camptothecin - analogs of which are being developed into chemotherapeutic drugs - because the resolution of stalled TOP1-DNA complexes requires processing by PNKP. We hypothesize that small molecule inhibitors of PNKP could bolster the effects of radio- and chemotherapies on cancer cells. I have identified eight compounds that effectively inhibit human PNKP and, with reduced potency, T4 PNK in vitro. These compounds act by reversibly inhibiting the substrate-enzyme interaction but they do not appear to sensitize U2OS cells to camptothecin.

Cancer is responsible for one fourth of the total deaths and is the second leading cause of death, behind heart disease, in the United States. However, there are as many approaches to curing cancer as there are types of cancer. One important issue in solid tumors is hypoxia, a lack of oxygen, which promotes angiogenesis and anaerobic metabolism, which can increase cancer progression and metastasis. The HIF transcription factor is responsible for the mediation of many processes involved during hypoxia and is linked to poor patient prognosis, increased cancer progression, and invasiveness of tumors. With this in mind, the HIF pathway has become an attractive target for small molecule inhibition. Herein, we describe the design and synthesis of small molecules that inhibit the HIF pathway. These compounds are based off an initial “hit” compound, KCN-1, from screening of a 10,000 compound library. KCN1 is both highly effective and has a low toxicity profile. Over 200 compounds have been synthesized by the Wang lab, with the best compound IVSR64b having an IC50 of 0.28 μM. Of special interest is that these compounds do not appear to have any inherent toxicity toward healthy tissues, but only affect cancer cells. Moreover, x-ray crystal structures for both KCN-1 and IVSR64b were obtained and used as the basis for computational modeling, which is still in progress.

No description available.

The oncogenic transcription factor STAT3 is aberrantly activated in over 70% of human tumours, including Multiple myeloma (MM). The present studies use both genetic and chemical tools to validate STAT3 as a therapeutic target, and demonstrate the anti-MM activity of a novel small molecule STAT3 inhibitor, BP-4-018. We show that shRNA-mediated STAT3 knockdown induces apoptosis in human myeloma cell lines (HMCLs). We translate these findings to a therapeutically relevant setting by demonstrating the broad anti-MM activity of BP-4-018 against HCMLs and primary patient samples, and demonstrate that BP-4-018 remains active against HMCLs co-cultured with bone marrow stroma. Inhibiting STAT3 via shRNA knockdown and BP-4-018 suppresses STAT3 transcriptional activity and down-regulates anti-apoptotic and proliferative STAT3 target genes. Finally, we show that BP-4-018 has activity in vivo, both alone and combined with subtherapeutic doses of bortezomib, without significant toxicities. Taken together, these data support the utility of STAT3 inhibitors for MM treatment.

The oncogenic transcription factor STAT3 is aberrantly activated in over 70% of human tumours, including Multiple myeloma (MM). The present studies use both genetic and chemical tools to validate STAT3 as a therapeutic target, and demonstrate the anti-MM activity of a novel small molecule STAT3 inhibitor, BP-4-018. We show that shRNA-mediated STAT3 knockdown induces apoptosis in human myeloma cell lines (HMCLs). We translate these findings to a therapeutically relevant setting by demonstrating the broad anti-MM activity of BP-4-018 against HCMLs and primary patient samples, and demonstrate that BP-4-018 remains active against HMCLs co-cultured with bone marrow stroma. Inhibiting STAT3 via shRNA knockdown and BP-4-018 suppresses STAT3 transcriptional activity and down-regulates anti-apoptotic and proliferative STAT3 target genes. Finally, we show that BP-4-018 has activity in vivo, both alone and combined with subtherapeutic doses of bortezomib, without significant toxicities. Taken together, these data support the utility of STAT3 inhibitors for MM treatment.

Hepatitis C virus (HCV) is remarkably capable of efficiently hijacking host cell pathways including lipid metabolism in the liver in order to create pro-viral environments for pathogenesis. It is becoming increasingly clear that identifying small molecule inhibitors that target host factors exploited by the virus will expand available HCV treatment options. As such, a thorough understanding of host-virus interactions is critical to the development of alternative therapeutic strategies. Hepatic lipid droplets (LDs) are recruited by HCV to play essential roles in the viral lifecycle. The intracellular location of LDs is modified upon interacting with viral structural core protein. This enables formation of platforms that support viral particle assembly. Because these interactions are non-static, capturing its dynamic processes in order to better understand viral assembly can be achieved with label-free molecular imaging enhanced with live-cell capabilities. Chemical biology approaches that includes CARS microscopy employed in a multi-modal imaging system was used to probe interactions between HCV and host LDs. By successfully tracking LD trajectories, we identified core protein’s ability to alter LD speed and control for LD directionality. Using protein expression model systems that allowed for simultaneous tracking of core protein and LDs, our data revealed that mutations in the core protein region that vary in hydrophobicity and LD binding strengths, are factors that control for differential modulation of LD kinetics. Furthermore, we measured bidirectional LD travels runs and velocities, and observed critical properties by which core protein induces LD migration towards regions of viral particle assembly. Given that many steps in the HCV lifecycle are directly linked to host lipid metabolism, it is not surprising that disrupting lipid biosynthetic pathways would negatively affect viral replication. From this outlook, we explored small molecule inhibitors that targeted several lipid metabolic pathways to study its antiviral properties. Using fluorescent probes covalently labeled to viral RNA, we captured the visualization of disrupted replication complexes upon antagonizing nuclear hormone receptors that are linked to regulating lipid homeostasis. Correspondingly, biochemistry and molecular imaging techniques were also employed to identify novel antiviral mechanisms of small molecule inhibitors that target additional HCV-dependent lipid metabolic pathways.