京都大学 / 新制・課程博士 / 博士(医学) / 甲第23606号 / 医博第4793号 / 新制||医||1055(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 林 康紀, 教授 古川 壽亮, 教授 髙橋 良輔 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Sepsis inflammation accelerates myeloid cell generation to compensate for rapid mobilization of the myeloid progenitors from bone marrow. This inflammation-driven myelopoiesis, however, generates myeloid progenitors with immunosuppressive functions that are unable to differentiate into mature, innate immune cells. The myeloid-derived suppressor cells (MDSCs) expand markedly in the later phases of sepsis, suppress both innate and adaptive immunity, and thus, elevate mortality. Using a murine model with myeloid-restricted deletion of the C/EBPβ transcription factor, we show that sepsis-induced generation of MDSCs depends on C/EBPβ. C/EBPβ myeloid cell–deficient mice did not generate MDSCs or develop immunosuppression and survived sepsis. However, septic mice still generated Gr1+ CD11b+ myeloid progenitors at the steady-state levels similar to the control sham mice, suggesting that C/EBPβ is not involved in healthy, steady-state myelopoiesis. C/EBPβ-deficient Gr1+ CD11b+ cells generated fewer monocyte- and granulocyte-like colonies than control mice did, indicating reduced proliferation potential, but differentiated normally in response to growth factors. Adoptive transfer of C/EBPβ-deficient Gr1+ CD11b+ cells from late septic mice exacerbated inflammation in control mice undergoing early sepsis, confirming they were not immunosuppressive. These results show that C/EBPβ directs a switch from proinflammatory to repressor myeloid cells and identifies a novel treatment target.

Animal and plant genomes produce numerous small RNAs (smRNAs) that regulate gene expression post-transcriptionally affecting metabolism, development, and epigenetic inheritance. In order to characterize the repertoire of endogenous microRNAs and potential gene targets, we conducted smRNA and mRNA expression profiling over nine experimental treatments of cultures from the dinoflagellate Symbiodinium sp. A1, a photosynthetic symbiont of scleractinian corals. We identified a total of 75 novel smRNAs in Symbiodinum sp. A1 that share stringent key features with functional microRNAs from other model organisms. A subset of 38 smRNAs was predicted independently over all nine treatments and their putative gene targets were identified. We found 3,187 animal-like target sites in the 3’UTRs of 12,858 mRNAs and 53 plantlike target sites in 51,917 genes. Furthermore, we identified the core RNAi protein machinery in Symbiodinium. Integration of smRNA and mRNA expression profiling identified a variety of processes that could be under microRNA control, e.g. regulation of translation, DNA modification, and chromatin silencing. Given that Symbiodinium seems to have a paucity of transcription factors and differentially expressed genes, identification and characterization of its smRNA repertoire establishes the possibility of a range of gene regulatory mechanisms in dinoflagellates acting post-transcriptionally.

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第19572号 / 医博第4079号 / 新制||医||1013(附属図書館) / 32608 / 京都大学大学院医学研究科医学専攻 / (主査)教授 萩原 正敏, 教授 小西 靖彦, 教授 齊藤 博英 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第20073号 / 医博第4166号 / 新制||医||1018(附属図書館) / 33189 / 京都大学大学院医学研究科医学専攻 / (主査)教授 高田 穣, 教授 武藤 学, 教授 武田 俊一 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第21003号 / 医博第4349号 / 新制||医||1028(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 山下 潤, 教授 木村 剛, 教授 小西 靖彦 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(医科学) / 甲第21689号 / 医科博第93号 / 新制||医||1036(附属図書館) / 京都大学大学院医学研究科医科学専攻 / (主査)教授 斎藤 通紀, 教授 中川 一路, 教授 竹内 理 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(医科学) / 甲第21694号 / 医科博第98号 / 新制||医科||7(附属図書館) / 京都大学大学院医学研究科医科学専攻 / (主査)教授 竹内 理, 教授 Shohab YOUSSEFIAN, 教授 藤渕 航 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Introduction: Colorectal cancer (CRC) is the most common malignant tumor in both sexes in the Czech Republic. Prognostic factors in CRC can be classified as clinical (stage at the time of diagnosis, histological type of tumor), genetic (RAS, BRAF), immunological (Immunoscore)and biochemical (CEA, CA 19-9, miRNA). MicroRNAs (miRNAs) regulate the expression of oncogenes and tumor suppressors. The regulatory function of miRNAs is influenced by single nucleotide polymorphisms (SNPs) of target miRNA binding sites (miRSNPs). Aims: To evaluate the currently available prognostic factors for CRC patients treated using targeted therapies and assess the role of novel ones, including miRNA. Methods: The thesis includes clinical works focused on targeted treatment of colorectal cancer, original work focused on the role of miRNA in colorectal cancer pathogenesis and especially as a prognostic and predictive marker, work focused on functional polymorphisms of DNA repair genes and a review article summarizing biochemical factors influencing the effect of fluoropyrimidine cytostatics in the treatment of colorectal cancer. Results: We have identified miR-17/92 as a non-invasive biomarker for predicting post-treatment prognosis in patients with a higher risk of relapse, as well as miRSNPs rs8679 polymorphisms as a...

Prostate cancer is the most commonly diagnosed cancer and the second most leading cause of cancer deaths in American men (www.cancer.org). Most prostate cancer-related deaths are due to the metastatic form of the disease. The 5-year relative survival rate in patient's diagnosed with metastatic prostate cancer is just 28%, as compared to 100% in patient's diagnosed with localized prostate cancer. This clearly indicates the lack of effective treatment available for metastatic prostate cancer. MicroRNAs (miRNAs) are small (18~23 nucleotide long) non-coding RNAs that can influence gene expression by binding to the 3'-untranslated region of coding RNAs at the post-transcriptional level. Some miRNAs has been termed as oncomirs due to their role in promoting tumor growth, invasion and metastasis. One such oncomir is microRNA-21 (miR-21) whose levels are often up-regulated in a number of cancers, including prostate cancer. MiR-21 increases the survival and invasiveness of cancer cells by suppressing its target tumor suppressor genes, namely programmed cell death 4 (PDCD4) and maspin. Thus, drugs which target miR-21 for inhibition could provide novel treatment options for metastatic prostate cancer. Resveratrol (3,5,4'-trihydroxystilbene) is a polyphenolic phytoalexin found in high quantities in various dietary sources, such as grapes, red wine, berries and peanuts. Various reports have demonstrated a significant role of resveratrol in the management of several old age diseases including cancer. The efficacy of resveratrol as an anti-cancer agent resides in its ability to interfere with cell proliferation and metastasis and enhancement of apoptosis. Resveratrol has been shown to act on several intracellular targets to exert these effects. However, the exact mechanism by which resveratrol mediates its beneficial cancer chemotherapeutic actions are not clear and is the focus of this study. Based on the reported data, we hypothesized that resveratrol mediates its anti-cancer action against metastatic prostate cancer by inhibiting the signaling pathway which involves miR-21 expression and function. To address this hypothesis, we show that resveratrol decreased cell viability, migration and invasiveness of androgen-receptor negative and highly aggressive human prostate cancer cells, PC-3M-MM2. These effects of resveratrol were associated with the inhibition of miR-21, since over-expression of miR- 21 with pre-miR-21 oligonucleotides attenuated resveratrol's effect on these cells. Additionally, resveratrol increased the expression of tumor suppressors, PDCD4 and maspin, which are negatively regulated by miR-21 and knockdown of PDCD4 by short interfering (si) RNA reversed the resveratrol's effect on prostate cancer cells. PC-3M-MM2 cells also exhibits high levels of phospho-Akt (pAkt), which were reduced by both resveratrol and LY294002, a known PI3-kinase inhibitor. MiR-21 expression in these cells appears to be dependent on Akt, as LY294002 reduced the levels of miR-21 along with a concurrent increase in PDCD4 expression. These in vitro findings were further corroborated in a severe combined immunodeficient (SCID) mouse xenograft model of prostate cancer. Oral administration of resveratrol not only inhibits the tumor growth but also decreased the incidence and number of metastatic lung lesions. These tumor- and metastatic-suppressive effects of resveratrol were associated with reduced miR-21 and pAkt, and elevated PDCD4 levels. Future investigation into the molecular mechanisms revealed that resveratrol suppressed prostate cancer growth by decreasing the levels of insulin-like growth factor-1 (IGF-1) and its receptor (R). Previous studies had associated elevated levels of serum IGF-1 with high risk of prostate cancer. IGF-1, after binding to its receptors, acts as a potent mitogen which stimulates cancer cell growth and proliferation mainly by activating Akt signaling pathway. Interestingly, this effect of resveratrol on IGF-1/IGF-1R was independent of its effect on miR-21. In summary, our data show that resveratrol exerts its anti-cancer effect on metastatic prostate cancer cells, at least in part, by targeting Akt/miR-21 pathway. These data highlight a potential molecular mechanism for resveratrol's anti-cancer action for the treatment of metastatic prostate cancer and suggest that inhibition of the IGF-1/Akt/miR-21 pathway is a rationale approach for the treatment prostate cancer metastasis.