Biochemical characterization of isoform-specific inhibitors of acyl-protein thioesterase enzymes

Honors (Bachelor's)BiochemistryUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/120593/1/hsinye.pd

Neoadjuvant stereotactic body radiation therapy, capecitabine, and liver transplantation for unresectable hilar cholangiocarcinoma

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102207/1/lt23757.pd

Survival Benefits of Neoadjuvant Chemotherapy Followed by Radical Surgery versus Radiotherapy in Locally Advanced Chemoresistant Cervical Cancer

The aim of this study was to analyze long-term survivals in patients with stage IB to IIA cervical cancer treated by neoadjuvant chemotherapy setting. Between February 1989 and January 1998, 94 women with previously untreated stage IB to IIA carcinoma of the uterine cervix who received cisplatin based neoadjuvant chemotherapy were enrolled in this study. All of patients with chemoresponse (complete response, n=15; partial response, n=47) and 16 patients with chemoresistance received radical surgery (RS group). The other 16 patients with chemoresistance received radiotherapy for definite treatment (RT group). In the RS group, the 10 yr survival estimation in patients with bulky tumors (diameter ≥4 cm, n=26) was similar to that with non-bulky tumors (83.3% vs. 89.3%, p=NS). In selected patients with chemoresistance, those treated by radiotherapy (n=16) showed significantly poorer survivals than those treated by radical surgery (n=16) [10 yr survival rates of RT (25%) vs. RS (76.4%), p=0.0111]. Our results support that a possible therapeutic benefit of neoadjuvant chemotherapy plus radical surgery is only in patients with bulky stage IB to IIA cervical cancer. In cases of chemoresistance, radical surgery might be a better definite treatment option

Determining crystal structures through crowdsourcing and coursework

We show here that computer game players can build high-quality crystal structures. Introduction of a new feature into the computer game Foldit allows players to build and real-space refine structures into electron density maps. To assess the usefulness of this feature, we held a crystallographic model-building competition between trained crystallographers, undergraduate students, Foldit players and automatic model-building algorithms. After removal of disordered residues, a team of Foldit players achieved the most accurate structure. Analysing the target protein of the competition, YPL067C, uncovered a new family of histidine triad proteins apparently involved in the prevention of amyloid toxicity. From this study, we conclude that crystallographers can utilize crowdsourcing to interpret electron density information and to produce structure solutions of the highest quality

The inhibitory effect of Gremlin-2 on adipogenesis suppresses breast cancer cell growth and metastasis

Abstract Background Gremlin-1 (GREM1) and Gremlin-2 (GREM2) are bone morphogenetic protein antagonists that play important roles in organogenesis, tissue differentiation, and tissue homeostasis. Although GREM1 has been reported to be involved in promoting various cancers, little has been reported about effects of GREM2 on cancer. Recently, it has been reported that GREM2 can inhibit adipogenesis in adipose-derived stromal/stem cells. However, as an inhibitor of adipogenesis, the role of GREM2 in cancer progression is not well understood yet. Methods Pre-adipocyte 3T3-L1 cells overexpressing mock or Grem2 were established using a lentiviral transduction system and differentiated into adipocytes-mock and adipocytes-Grem2, respectively. To investigate the effect of adipocyte-Grem2 on breast cancer cells, we analyzed the proliferative and invasion abilities of spheroids using a 3D co-culture system of breast cancer cells and adipocytes or conditioned medium (CM) of adipocytes. An orthotopic breast cancer mouse model was used to examine the role of adipocytes-Grem2 in breast cancer progression. Results Grem2 overexpression suppressed adipogenesis of 3T3-L1 cells. Proliferative and invasion abilities of spheroids formed by co-culturing MTV/TM-011 breast cancer cells and adipocytes-Grem2 were significantly reduced compared to those of spheroids formed by co-culturing MTV/TM-011 cells and adipocytes-mock. Compared to adipocytes-mock, adipocytes-Grem2 showed decreased mRNA expression of several adipokines, notably IL-6. The concentration of IL-6 in the CM of these cells was also decreased. Proliferative and invasive abilities of breast cancer cells reduced by adipocytes-Grem2 were restored by IL-6 treatment. Expression levels of vimentin, slug, and twist1 in breast cancer cells were decreased by treatment with CM of adipocytes-Grem2 but increased by IL-6 treatment. In orthotopic breast cancer mouse model, mice injected with both MTV/TM-011 cells and adipocytes-Grem2 showed smaller primary tumors and lower lung metastasis than controls. However, IL-6 administration increased both the size of primary tumor and the number of metastatic lung lesions, which were reduced by adipocytes-Grem2. Conclusions Our study suggests that GREM2 overexpression in adipocytes can inhibit adipogenesis, reduce the expression and secretion of several adipokines, including IL-6, and ultimately inhibit breast cancer progression

Affinity-Based Selectivity Profiling of an In-Class Selective Competitive Inhibitor of Acyl Protein Thioesterase 2

Activity-based protein profiling (ABPP) has revolutionized the discovery and optimization of active-site ligands across distinct enzyme families, providing a robust platform for in-class selectivity profiling. Nonetheless, this approach is less straightforward for profiling reversible inhibitors and does not access proteins outside the ABPP probe’s target profile. While the active-site competitive acyl protein thioesterase 2 inhibitor ML349 (<i>K</i>_i = 120 nM) is highly selective within the serine hydrolase enzyme family, it could still interact with other cellular targets. Here we present a chemoproteomic workflow to enrich and profile candidate ML349-binding proteins. In human cell lysates, biotinylated-ML349 enriches a recurring set of proteins, including metabolite kinases and flavin-dependent oxidoreductases that are potentially enhanced by avidity-driven multimeric interactions. Confirmatory assays by native mass spectrometry and fluorescence polarization quickly rank-ordered these weak off-targets, providing justification to explore ligand interactions and stoichiometry beyond ABPP

Tetraspanin TM4SF5 mediates loss of contact inhibition through epithelial-mesenchymal transition in human hepatocarcinoma

The growth of normal cells is arrested when they come in contact with each other, a process known as contact inhibition. Contact inhibition is lost during tumorigenesis, resulting in uncontrolled cell growth. Here, we investigated the role of the tetraspanin transmembrane 4 superfamily member 5 (TM4SF5) in contact inhibition and tumorigenesis. We found that TM4SF5 was overexpressed in human hepatocarcinoma tissue. TM4SF5 expression in clinical samples and in human hepatocellular carcinoma cell lines correlated with enhanced p27Kip1 expression and cytosolic stabilization as well as morphological elongation mediated by RhoA inactivation. These TM4SF5-mediated effects resulted in epithelial-mesenchymal transition (EMT) via loss of E-cadherin expression. The consequence of this was aberrant cell growth, as assessed by S-phase transition in confluent conditions, anchorage-independent growth, and tumor formation in nude mice. The TM4SF5-mediated effects were abolished by suppressing the expression of either TM4SF5 or cytosolic p27Kip1, as well as by reconstituting the expression of E-cadherin. Our observations have revealed a role for TM4SF5 in causing uncontrolled growth of human hepatocarcinoma cells through EMT