Sphingosine 1-phosphate (S1P) is a lipid chemoattractant molecule. Once formed, S1P can be transported extracellularly by S1P transporters spinster homolog 2 (Spns2) or major facilitator domain containing 2B (mfsd2b). In the extracellular space, S1P can bind to S1P-specific G-protein coupled receptors (S1PR), which initiate many signaling pathways. A critical role of extracellular S1P is its ability to cause lymphocyte egress, which can have implications for inflammatory and autoimmune diseases. For this reason, there has been a growing interest in exploring potential spns2 inhibitors to further elucidate their therapeutic potential. Initial screenings confirmed that fused heterocycles, including phthalimide and benzoxazoles, demonstrated moderate inhibition of Spns2 using a HeLa cell assay. An extensive structure-activity relationship (SAR) study of these scaffolds was performed to analyze the impact of various amine head groups, regioisomers, and alkyl tails on performance. It was determined that 2-aminobenzoxazoles with secondary amines were potent inhibitors of the transporter. Additionally, the position of the lipophilic tail moiety played a large role in activity. From these modifications, SLB1122168 (2.44p) was found to be our lead compound. It was determined that (2.44p) had an IC50 of 94 ± 6 nM and was shown to be efficacious in decreasing lymphocyte count by 55% in a dose-dependent manner in both rat and mice models. The discovery of (2.44p) can serve as a novel chemical tool to investigate Spns2 biology and use it as a probe to determine the potential of Spns2 as a drug target. Organoboron compounds are useful synthetic intermediates in forming C-X, C-C, and C-H bonds. One way to synthesize these compounds is through copper catalysis. Copper is favorable to other transition metals because it is an Earth-abundant, low-cost metal that can be utilized in regio- and stereoselective reactions. Conjugated 1,3-enynes are important functional groups that iii are found in active natural products, organic synthetic intermediates, and materials. Previous methods used rare transition metals, designer ligands, or harsh acidic conditions to synthesize such compounds. In this dissertation, we developed a stereoselective one-pot copper-catalyzed semi-reduction of 1,3-diynes to produce (Z)-1,3-enynes. This method uses Cu(OAc)2, HBpin and Xantphos to successfully synthesize (Z)-1,3-enynes that were tolerated well over a broad substrate scope, including heterocyclic, alkyl, and aryl substituents. It was determined that this reaction went through a 2-boryl intermediate which was facilitated by a CuH species. / Doctor of Philosophy / Autoimmune diseases are caused by immune cells attacking healthy cells. The signaling lipid sphingosine-1-phosphate (S1P) plays a major role in trafficking immune cells, in which immune cells follow the S1P gradient from low concentrations (secondary lymphoid tissues) to high concentrations (lymph). In the case of multiple sclerosis, immune cells can attack healthy neurons that cause a myriad of symptoms. Currently, there are four drugs approved by the Food and Drug Administration (FDA) targeting the S1P pathway for multiple sclerosis. In all cases, these drugs act as S1P-receptor (S1PR) functional antagonists, which decreases the amount of extracellular S1P, which in turn decreases the immune cells in the lymph that can attack healthy cells. Unfortunately, all four drugs exhibit on-target cardiovascular side effects. To circumvent the on-target side effects seen in current FDA-approved drugs, other nodes of the S1P pathway have been assessed for multiple sclerosis. One node of interest is spinster homolog 2 (Spns2), a transporter of S1P, whose inhibition has also been shown to decrease extracellular S1P. In this dissertation, we will be assessing various inhibitors for their in vitro and in vivo properties. 1,3-Enynes are a functional group found in medicinally relevant compounds and can be used as intermediates to make more complex compounds. Current methods to make this functional group use expensive rare metals or harsh acidic conditions. We developed new methods that utilized copper, an abundant metal, and boron, an atom whose empty p orbital allows for unique reactivity. Utilizing a copper-hydride species allowed us to semi-reduce 1,3-diynes to (Z)-1,3-enynes, where water was used instead of acid to allow for the semi-reduction to occur. This reaction was shown to tolerate a wide range of substrates and gave good to excellent yield.

Over the past two decades, protein kinases have been intensively investigated as targets to treat neoplastic diseases. Many protein kinase inhibitors not only have therapeutic potential but are becoming invaluable reagents for the study of cell signaling. We aspired to use our Cyclin-Dependent Kinase 8 inhibitor, Q-12, as a probe for biomarker discovery for CDK8 inhibitor sensitive tumor types. Q-12 shows potent inhibition of cell viability and induction of apoptosis process in some triple-negative breast cancer and colorectal cancer cell lines in vitro. Western blot results indicate that the reduction of STAT1 phosphorylation could be a robust indicator of CDK8 target engagement in all three cancer cell lines used upon Q-12 treatment. Q-12 treatment of triple-negative breast cancer cell line (MDA-MB-468) decreases STAT1 phosphorylation but increases STAT3 phosphorylation. Q-12 activity in MDA-MB-468 cell is dependent on the activation of STAT3 phosphorylation. All results suggest that there may be a critical STAT1 to STAT3 ratio that may serve as a biomarker for CDK8 inhibitor sensitivity. In this precision medicine era, the discovery of biomarker is urgently needed to minimize the risks of severe side-effects by traditional chemotherapy and improve diagnosis and monitor therapy response across a wide spectrum of disease, especially heterogenous type of disease, like cancer.

Immunotherapy has emerged as one of the four “standard” cancer therapies, alongside surgery, chemotherapy, and radiotherapy. Immune checkpoint inhibitor (ICI) therapy is an immunotherapy that blocks inhibitory immune checkpoint interactions, allowing T cells and other immune cells to kill tumor cells. In the tumor microenvironment, there is often overexpression of immune checkpoint proteins, whose binding interaction with cytotoxic T cells and other immune cells results in the dampening of the antitumor response. Programmed cell death protein 1 (PD-1) and T-lymphocyte-associated protein 4 (CTLA-4) are the two most targeted immune checkpoint proteins. Antibodies against PD-1 and CTLA-4, as well as other checkpoint proteins, are approved for clinical use as well as in clinical trials. While ICIs have changed the treatment landscape for many cancers, particularly those with significant immunogenicity, only 20-40% of patients respond to ICI therapy. Many factors are behind the lack of response and resistance, and significant efforts are aimed at improving the response to ICI therapy. One major area is modulating the gut microbiome, as it is well-established that microbial dysbiosis is associated with various human diseases. The concept is that by modulating the microbiome, we might be able to return it to a composition more similar to that seen in healthy individuals or provide microorganisms beneficial to clinical response. In the case of ICI therapy, it is proposed that there is a connection between certain microbial species and the immune system via metabolites and other signaling effects. The microbiome can be manipulated through many methods, including fecal microbiota transplantation (FMT), transferring bacterial isolates or consortia, probiotics, antibiotics, and soluble dietary fiber. For clinical insights, it is important to consider how the pre-treatment microbiome of patients may affect their response to ICI therapy, as well as how their microbiomes can be manipulated to enhance their response. Initial clinical trials have been promising, but this is an emerging field with additional work to be done. Particularly, a better understanding of the microorganisms involved in the response to ICI therapy and the mechanism by which they communicate with the immune system is essential. Future studies will need to be much larger to reduce noise between studies and to allow for emerging computational techniques to be applied.

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京都大学 / 新制・課程博士 / 博士(人間健康科学) / 甲第24292号 / 人健博第107号 / 新制||人健||8(附属図書館) / 京都大学大学院医学研究科人間健康科学系専攻 / (主査)教授 藤井 康友, 教授 岡 昌吾, 教授 滝田 順子 / 学位規則第4条第1項該当 / Doctor of Human Health Sciences / Kyoto University / DFAM

When system runs are modeled with interval orders, interval order structures are useful tools to model abstract concurrent histories, i.e. sets of equivalent system runs. For the general cases, Mazurkiewicz traces allow a representation of the entire partial order by a single sequence with independency relations, and Comtraces allow a representation of stratified order structures by single step sequences with appropriate simultaneity and serializability relations. Unfortunately, both of them are unable to clearly describe the abstract interval order semantics of inhibitor nets. The goal of the thesis is to provide a monoid based model called Interval Traces that would allow a single sequence of beginnings and endings to represent the entire stratified order structures as well as all equivalent interval order observations. And the thesis will also show how interval order structures can be modelled by interval traces and how interval traces can be used to describe interval order semantics. / Thesis / Doctor of Philosophy (PhD)

The full text will be available at the end of the extended embargo: 21st Feb 2026

The development of new anticancer drugs is necessary in order deal with the disease and with the drawbacks of currently applied drugs. Epigenetic dysregulations are a central hallmark of cancerogenesis and histone deacetylases (HDACs) emerged as promising anticancer targets. HDAC inhibitors are promising epigenetic anticancer drugs and new HDAC inhibitors are sought for in order to obtain potent drug candidates. The new HDAC inhibitor SF5-SAHA was synthesized and analyzed for its anticancer properties. The new compound SF5-SAHA showed strong inhibition of tumor cell growth with IC50 values similar to or lower than that of the clinically applied reference compound vorinostat/SAHA (suberoylanilide hydroxamic acid). Target specific HDAC inhibition was demonstrated by Western blot analyses. Unspecific cytotoxic effects were not observed in LDH-release measurements. Pro-apoptotic formation of reactive oxygen species (ROS) and caspase-3 activity induction in prostate carcinoma and hepatocellular carcinoma cell lines DU145 and Hep-G2 seem to be further aspects of the mode of action. Antiangiogenic activity of SF5-SAHA was observed on chorioallantoic membranes of fertilized chicken eggs (CAM assay). The presence of the pentafluorothio-substituent of SF5-SAHA increased the antiproliferative effects in both solid tumor and leukemia/lymphoma cell models when compared with its parent compound vorinostat. Based on this preliminary study, SF5-SAHA has the prerequisites to be further developed as a new HDAC inhibitory anticancer drug candidate.

Ruthenium-based complexes have received much interest as potential metallodrugs. In this work, four RuII complexes bearing a dicarbollide moiety, a carbonyl ligand, and a phenanthroline-based ligand were synthesized and characterized, including single crystal diffraction analysis of compounds 2, 4, and 5 and an observed side product SP1. Complexes 2–5 are air and moisture stable under ambient conditions. They show excellent solubility in organic solvents, but low solubility in water.

The increasing knowledge of molecular drivers of tumorigenesis has fueled targeted cancer therapies based on specific inhibitors. Beyond “classic” oncogene inhibitors, epigenetic therapy is an emerging field. Epigenetic alterations can occur at any time during cancer progression, altering the structure of the chromatin, the accessibility for transcription factors and thus the transcription of genes. They rely on post-translational histone modifications, particularly the acetylation of histone lysine residues, and are determined by the inverse action of histone acetyltransferases (HATs) and histone deacetylases (HDACs). Importantly, HDACs are often aberrantly overexpressed, predominantly leading to the transcriptional repression of tumor suppressor genes. Thus, histone deacetylase inhibitors (HDACis) are powerful drugs, with some already approved for certain hematological cancers. Albeit HDACis show activity in solid tumors as well, further refinement and the development of novel drugs are needed. This review describes the capability of HDACis to influence various pathways and, based on this knowledge, gives a comprehensive overview of various preclinical and clinical studies on solid tumors. A particular focus is placed on strategies for achieving higher efficacy by combination therapies, including phosphoinositide 3-kinase (PI3K)-EGFR inhibitors and hormone- or immunotherapy. This also includes new bifunctional inhibitors as well as novel approaches for HDAC degradation via PROteolysis-TArgeting Chimeras (PROTACs).