Effects of Sappan Lignum and Chuanxiong Rhizoma on Expression of ABCG2 Protein of PG-BE1 Stem Like Cells in Vivo / 中国中医药信息杂志

Objective To observe the effects of different doses of Sappan Lignum and Chuanxiong Rhizoma on tumor stem cells marker ABCG2 in vivo. Methods Sphere cells obtained from serum culture were inoculated in nude mouse armpit, which were randomly divided into 5 groups: control group, Sappan Lignum high- and low-dose groups, and Chuanxiong Rhizoma high- and low-dose groups. Each medication group was given relevant medicine for gavage. 21 days later, inhibition tumor rate and ABCG2 protein and mRNA expression were detected with confocal microscope, Western blot, and RT-PCR. Results The sphere cells obtained from serum free culture had the abilities of cancer stem cells, such as proliferation, anti-aptosis and high expression of cancer stem cells markers. Chuanxiong Rhizoma high- and low-dose groups could inhibit tumor growth (P0.05). Compared with the control group, Chuanxiong Rhizoma low-dose group could significantly inhibit the expression of resistant protein of ABCG2. Sappan Lignum high- and low-dose groups could not inhibit the protein expression of ABCG2. Each medication group up-regulated the mRNA expression of ABCG2 except for Chuanxiong Rhizoma low-dose group. Conclusion Low dose of Chuanxiong Rhizoma can inhibit the expression of ABCG2 protein levels, which can be the targeting killer for cancer stem cells.

OCT-1, ABCB1, and ABCG2 Expression in Imatinib-Resistant Chronic Myeloid Leukemia Treated with Dasatinib or Nilotinib / 전남의대학술지

This study explored drug transporter expression levels and their impact on clinical response to imatinib and second-generation tyrosine kinase inhibitors (TKIs) in imatinib- resistant chronic myeloid leukemia (CML). Imatinib-resistant chronic phase CML patients treated with dasatinib (n=10) and nilotinib (n=12) were enrolled. The mRNA expression of the OCT-1, ABCG2, and ABCB1 genes was quantified by using paired bone marrow samples obtained before administering imatinib and at the point of detecting imatinib resistance (just before starting second-generation TKIs). The expression levels of OCT-1 and ABCG2 were lower in follow-up than in imatinib-naive samples. ABCB1 revealed highly variable expression levels before and after imatinib treatment. In addition, median ABCB1 expression in follow-up samples was lower in patients achieving complete cytogenetic response or major molecular response during imatinib treatment than in failed patients. Higher ABCG2 expression in imatinib-exposed samples showed a negative impact on optimal response to dasatinib. Patients with higher ABCG2 expression in imatinib-exposed samples also had shorter progression- free survival with dasatinib treatment. However, no significant correlation was found between these drug transporter expression levels in imatinib-naive or imatinib- exposed samples and responses to nilotinib. In imatinib-resistant CML, OCT-1 and ABCG2 mRNA expression decreased after imatinib treatment. Patients with higher ABCG2 expression in imatinib-exposed samples showed poor treatment outcome with dasatinib. On the other hand, a higher expression level of ABCB1 in imatinib-exposed samples did not affect second-generation TKI responses but was correlated with poor imatinib responses.

OCT-1, ABCB1, and ABCG2 Expression in Imatinib-Resistant Chronic Myeloid Leukemia Treated with Dasatinib or Nilotinib / 전남의대학술지

This study explored drug transporter expression levels and their impact on clinical response to imatinib and second-generation tyrosine kinase inhibitors (TKIs) in imatinib- resistant chronic myeloid leukemia (CML). Imatinib-resistant chronic phase CML patients treated with dasatinib (n=10) and nilotinib (n=12) were enrolled. The mRNA expression of the OCT-1, ABCG2, and ABCB1 genes was quantified by using paired bone marrow samples obtained before administering imatinib and at the point of detecting imatinib resistance (just before starting second-generation TKIs). The expression levels of OCT-1 and ABCG2 were lower in follow-up than in imatinib-naive samples. ABCB1 revealed highly variable expression levels before and after imatinib treatment. In addition, median ABCB1 expression in follow-up samples was lower in patients achieving complete cytogenetic response or major molecular response during imatinib treatment than in failed patients. Higher ABCG2 expression in imatinib-exposed samples showed a negative impact on optimal response to dasatinib. Patients with higher ABCG2 expression in imatinib-exposed samples also had shorter progression- free survival with dasatinib treatment. However, no significant correlation was found between these drug transporter expression levels in imatinib-naive or imatinib- exposed samples and responses to nilotinib. In imatinib-resistant CML, OCT-1 and ABCG2 mRNA expression decreased after imatinib treatment. Patients with higher ABCG2 expression in imatinib-exposed samples showed poor treatment outcome with dasatinib. On the other hand, a higher expression level of ABCB1 in imatinib-exposed samples did not affect second-generation TKI responses but was correlated with poor imatinib responses.

Multidrug resistance mediated by ABCG2 / 国际肿瘤学杂志

ABCG2 is a member of the ATP-binding cassette (ABC) transporter family.The overexpression of ABCG2 is identified as one of the important mechanisms that limiting cellular accumulation of various compounds.With regard to its broad substrate spectrum including various anticancer drugs and environmental carcinogens,the function of ABCG2 is associated with multidrug resistance (MDR) and tumor development.ABCG2 as a target site to reverse MDR has been widely concered.

Adenovirus adenine nucleotide translocator-2 shRNA effectively induces apoptosis and enhances chemosensitivity by the down-regulation of ABCG2 in breast cancer stem-like cells

Cancer stem cells (CSCs) are resistant to chemo- and radio-therapy, and can survive to regenerate new tumors. This is an important reason why various anti-cancer therapies often fail to completely control tumors, although they kill and eliminate the bulk of cancer cells. In this study, we determined whether or not adenine nucleotide translocator-2 (ANT2) suppression could also be effective in inducing cell death of breast cancer stem-like cells. A sub-population (SP; CD44+/CD24-) of breast cancer cells has been reported to have stem/progenitor cell properties. We utilized the adeno-ANT2 shRNA virus to inhibit ANT2 expression and then observed the treatment effect in a SP of breast cancer cell line. In this study, MCF7, MDA-MB-231 cells, and breast epithelial cells (MCF10A) mesenchymally-transdifferentiated through E-cadherin knockdown were used. ANT2 expression was high in both stem-like cells and non-stem-like cells of MCF7 and MDA-MB-231 cells, and was induced and up-regulated by mesenchymal transdifferentiation in MCF10A cells (MCF10AEMT). Knockdown of ANT2 by adeno-shRNA virus efficiently induced apoptotic cell death in the stem-like cells of MCF7 and MDA-MB-231 cells, and MCF10AEMT. Stem-like cells of MCF7 and MDA-MB-231, and MCF10AEMT cells exhibited increased drug (doxorubicin) resistance, and expressed a multi-drug resistant related molecule, ABCG2, at a high level. Adeno-ANT2 shRNA virus markedly sensitized the stem-like cells of MCF7 and MDA-MB-231, and the MCF10AEMT cells to doxorubicin, which was accompanied by down-regulation of ABCG2. Our results suggest that ANT2 suppression by adeno-shRNA virus is an effective strategy to induce cell death and increase the chemosensitivity of stem-like cells in breast cancer.

Expression and clinical significance of ABCG2 protein in hepatocellular carcinoma / 中华消化外科杂志

Objective To investigate the expression and clinical significance of ABCG2 protein in hepato-cellular carcinoma (HCC). Methods Specimens of HCC were collected at The First Aifiliated Hospital of Sun Yat-sen University from January 2005 to December 2006. The expression of ABCG2 protein in 165 samples of HCC tissue, 25 samples of normal liver tissue and 40 samples of cirrhotic liver tissue was detected using immunohisto-chemistry. The correlation between the expression of ABCG2 protein and clinicopathological characters was then analyzed. Enumeration data, survival rate and the difference between groups were analyzed with a chi-square test, the Kaplan-Meier method and Log-rank test, respectively. Results ABCG2 protein expression was weakly posi-tive in all normal and cirrhotic liver tissues. In HCC tissues, the expression of ABCG2 protein was strongly positive in 66 cases and weakly positive in 99 cases. The expression of ABCG2 protein was related to tumor diameter, tumor number, adjacent organ invasion and TNM stages (χ2 =8. 130, 14. 279, 4. 820, 21. 179, P <0. 05). Kaplan-Meier survival analysis revealed that patients with strongly positive ABCG2 protein had a significantly lower 3-year overall survival (24. 1%) compared with those with weakly positive ABCG2 protein (39. 4%) (χ2 = 15.716, P<0.05). Conclusions The expression level of ABCG2 protein is related to tumor invasiveness, TNM stage and prognosis. ABCG2 has the potential to become a new target for HCC treatment.