GLUCOSYLCERAMIDE SYNTHASE IN A NOVEL TARGET FOR CANCER TREATMENT

这个子项目是许多利用 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 肿瘤干细胞是肿瘤发生和转移的重要因素。在化疗过程中存活的肿瘤总是显示出对治疗的实质性抵抗和侵袭性转移。耐药癌症的这些特性表明存在一种未被识别的干细胞类型，即耐药癌症干细胞。我们假设，耐药癌症干细胞（DR-CSC）是不可治愈的癌症的原因;葡萄糖神经酰胺合酶，神经酰胺糖基化的关键酶，调节化疗对DR-CSC形成的表观遗传效应。来自人MCF-7乳腺癌细胞的癌症干细胞的表征发现，长期和低剂量的阿霉素治疗（0.1 μ M，超过10代）因此增加了侧群细胞的数量。除了具有典型标志物CD 44+和CD 24-的乳腺癌干细胞外，还用MDR 1、SSEA-3和Oct-4标志物表征了新型干细胞。将GCS基因导入MCF-7-AdrR细胞后，MCF-7-AdrR细胞的数量增加，而沉默GCS基因后，MCF-7-AdrR细胞的数量减少。耐药MCF-7-AdrR细胞（5 × 105个/只）接种裸鼠后，所有裸鼠肺转移瘤均成瘤，而反义GCS基因转染的MCF-7-AdrR/asGCS细胞（10只/只）未成瘤。在体内研究中，低剂量阿霉素治疗（0.5 mg/kg/周，21天）诱导肿瘤干细胞产生耐药性。然而，针对GCS的混合骨架寡核苷酸（MBO-asGCS，1 mg/kg/3天）处理减少了癌症干细胞，并且这些细胞对阿霉素敏感。这些初步数据表明，GCS引起的神经酰胺糖基化与癌症化疗期间的DR-CSC形成相关。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Cancer stem cell is responsible for tumorigenesis and metastasis. Tumors that are survived during the course of chemotherapy always display a substantial resistance to therapy and aggressive metastasis. These properties of drug-resistant cancers suggest the existence of an unrecognized type of stem cell, drug-resistant cancer stem cell. We hypothesize that drug-resistant cancer stem cell (DR-CSC) is a cause of incurable cancers; glucosylceramide synthase, a key enzyme for ceramide glycosylation, modulates the epigenetic effects of chemotherapy on the formation of DR-CSC formation. Characterization of cancer stem cell from human MCF-7 breast cancer cells found that long-term and low-dose of doxorubicin treatments (0.1 ¿M, more than 10 passages) consequently increased the numbers of side population cells. Addition to breast cancer stem cell with typical markers of CD44+ and CD24-, a new type of stem cell was characterized with markers of MDR1, SSEA-3 and Oct-4. Introducing GCS gene into MCF-7-AdrR cells increased, and silence GCS gene decreased the numbers of this type cancer stem cells. Inoculation of drug-resistant MCF-7-AdrR cells (5x105 cells/mice) formed tumors in all athymic nude mice with lung metastasis, however, antisense GCS gene transfected cells (MCF-7-AdrR/asGCS) could not form tumor (10 mice/group). In vivo study, low-dose of doxorubicin treatment (0.5 mg/kg/week, 21 days) induced cancer stem cells with drug-resistance. However, mixed backbone oligonucleotide against GCS (MBO-asGCS, 1 mg/kg/3-day) treatment decreased cancer stem cells and those cells were sensitive to doxorubicin. These preliminary data indicate that ceramide glycosylation by GCS is associated with DR-CSC formation during cancer chemotherapy.