Chang Gong

Sun Yat-Sen University, Shengcheng, Guangdong, China

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Publications (20)125 Total impact

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    ABSTRACT: The prognostic value of serum tumor markers (STMs) in nonmetastatic breast cancer patients with different molecular subtypes (luminal A, luminal B, and nonluminal) remains unknown. It is our institutional policy to assess the STMs in nonmetastatic patients. This retrospective single-center study is to investigate the association between STMs and clinical outcomes in nonmetastatic patients and the impact of molecular subtypes. A total of 368 patients with available clinical outcomes, tumor node metastasis stages, and STMs levels were included. The serum level of preoperative STMs (carcinoembryonic antigen [CEA], cancer antigen 125 [CA-125], and cancer antigen 15-3 [CA 15-3]) was analyzed and compared among distinct molecular subtypes. Univariate and multivariate analyses were used to investigate the relationship among STMs concentrations and patient outcomes. The median levels of CA 15-3 were 10.2, 8.1 and 7.1 U/mL in patients with luminal A, luminal B, and nonluminal diseases, respectively (P = 0.015). The levels of CEA and CA-125 were similar among the subtypes. Multivariate analysis showed that higher CA 15-3 was significantly associated with worse clinical outcomes exclusively in luminal A patients (P = 0.033 for metastasis-free survival and P = 0.030 for relapse-free survival). In contrast, higher CEA was a significant prognostic factor for worse clinical outcomes (P = 0.003 for metastasis-free survival and P = 0.015 for metastasis-free survival) in nonluminal groups. The prognostic value of preoperative STMs may be different among molecular subtypes. Patients with luminal A diseases had higher levels of CA 15-3. Higher preoperative CA 15-3 was associated with worse clinical outcomes exclusively in patients with luminal A diseases.
    Journal of Surgical Research 03/2014; · 2.02 Impact Factor
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    ABSTRACT: TGF-β has paradoxical effects on cancer cell proliferation, as it suppresses proliferation of normal epithelial and low-invasive cancer cells, but enhances that of high-invasive cancer cells. However, how cancer cells acquire the ability to evade the tumor-suppressing effects of TGF-β, yet still take advantage of its tumor-promoting effects, remains elusive. Here, we identified miR-106b as a molecular switch to determine TGF-β effects on cell proliferation. TGF-β1 enhances the transcription of miR-106b via a promoter independent of its host gene MCM7 by activating c-jun. In high-invasive breast cancer cells, miR-106b is upregulated by TGF-β1 at a much higher level than that in normal or low-invasive cancer cells. Accumulation of miR-106b counterbalances TGF-β growth-inhibiting effects by eliminating activated retinoblastoma (RB) and results in enhanced proliferation. Furthermore, miR-106b mediates TGF-β effects on tumor growth and metastasis in breast cancer xenografts. In addition, miR-106b expression is elevated in higher stage tumors and correlated with tumor progression in breast cancer patients. These findings suggest that high level of miR-106b induced by TGF-β determines the tumor-promoting effects of TGF-β in breast cancer.Oncogene advance online publication, 2 December 2013; doi:10.1038/onc.2013.525.
    Oncogene 12/2013; · 7.36 Impact Factor
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    ABSTRACT: Identification of new nasopharyngeal carcinoma (NPC) biomarkers is of great clinical value for the diagnosis and treatment of NPC. HOTAIR, a cancer-related long noncoding RNA, was tested and its prognostic value for NPC was evaluated. Determined by In situ hybridization (ISH), 91 of 160 (56.87%) paraffin-embedded NPC biopsies showed high expression levels of HOTAIR (Staing Index, SI score ≥ 6). HOTAIR was up-regulated in tumors with a larger tumor (p = 0.021), more advanced clinical staging (P = 0.012) and increased lymph node tumor burden (P = 0.005). Quantified by real-time PCR, HOTAIR expression levels in fresh tissue and paraffin-embedded samples were 5.2˜48.4-fold higher compared with non-cancer tissue samples. Moreover, HOTAIR expression levels increased with clinical stage progression, which was consistent with ISH findings in the paraffin-embedded tissue. Most importantly, NPC patients with higher HOTAIR levels had poor prognosis for overall survival by univariate and multivariate analysis. In addition, HOTAIR mediated the migration, invasion and proliferation of NPC cells in vitro. HOTAIR is a potential biomarker for the prognosis of NPC, and dysregulation of HOTAIR may play an important role in NPC progression.
    Cancer Science 01/2013; · 3.48 Impact Factor
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    ABSTRACT: Malignant tissue contains a rare population of multi-potent cells known as cancer stem-like cells (CSCs). Autophagy is an important mechanism in cancer cell survival and tumor growth; it can both suppress malignant transformation and promote the growth of established cancers. However, the molecular mechanisms underlying the tumor-promoting and tumor-suppressing functions of autophagy in CSCs are not understood. Our work demonstrates that a prosurvival autophagic pathway is critical for breast CSC maintenance. Notably, we provide new evidence for the existence of two separate, context-dependent, autophagic programs that are regulated in opposite ways by BECN1.
    Autophagy 09/2012; 8(12). · 12.04 Impact Factor
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    ABSTRACT: Malignant breast tissue contains a rare population of multi-potent cells with the capacity to self-renew; these cells are known as cancer stem-like cells (CSCs) or tumor-initiating cells. Primitive mammary CSCs/progenitor cells can be propagated in culture as floating spherical colonies termed 'mammospheres'. We show here that the expression of the autophagy protein Beclin 1 is higher in mammospheres established from human breast cancers or breast cancer cell lines (MCF-7 and BT474) than in the parental adherent cells. As a result, autophagic flux is more robust in mammospheres. We observed that basal and starvation-induced autophagy flux is also higher in aldehyde dehydrogenase 1-positive (ALDH1(+)) population derived from mammospheres than in the bulk population. Beclin 1 is critical for CSC maintenance and tumor development in nude mice, whereas its expression limits the development of tumors not enriched with breast CSCs/progenitor cells. We found that decreased survival in autophagy-deficient cells (MCF-7 Atg7 knockdown cells) during detachment does not contribute to an ultimate deficiency in mammosphere formation. This study demonstrates that a prosurvival autophagic pathway is critical for CSC maintenance, and that Beclin 1 plays a dual role in tumor development.Oncogene advance online publication, 25 June 2012; doi:10.1038/onc.2012.252.
    Oncogene 06/2012; · 7.36 Impact Factor
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    ABSTRACT: Malignant breast tissue contains a rare population of multi-potent cells with the capacity to self-renew; these cells are known as cancer stem-like cells (CSCs) or tumor-initiating cells. Primitive mammary CSCs/progenitor cells can be propagated in culture as floating spherical colonies termed ‘mammospheres’. We show here that the expression of the autophagy protein Beclin 1 is higher in mammospheres established from human breast cancers or breast cancer cell lines (MCF-7 and BT474) than in the parental adherent cells. As a result, autophagic flux is more robust in mammospheres. We observed that basal and starvation-induced autophagy flux is also higher in aldehyde dehydrogenase 1-positive (ALDH1þ) population derived from mammospheres than in the bulk population. Beclin 1 is critical for CSC maintenance and tumor development in nude mice, whereas its expression limits the development of tumors not enriched with breast CSCs/progenitor cells. We found that decreased survival in autophagy-deficient cells (MCF-7 Atg7 knockdown cells) during detachment does not contribute to an ultimate deficiency in mammosphere formation. This study demonstrates that a prosurvival autophagic pathway is critical for CSC maintenance, and that Beclin 1 plays a dual role in tumor development.
    Oncogene 01/2012; · 7.36 Impact Factor
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    ABSTRACT: Tumor-initiating cells are resistant to chemotherapy, but how microRNAs play a role in regulating drug resistance of breast tumor-initiating cells (BT-IC) needs to be clarified. Lentivirus-mediated miR-128 transduction was done in BT-ICs, enriched by mammosphere cultures or CD44(+)CD24(-) fluorescence-activated cell sorting. Apoptosis and DNA damage were determined upon treatment with doxorubicin. Expression of miR-128 in breast cancer tissues was examined by in situ hybridization and correlated with breast tumor response to neoadjuvant chemotherapy and patient survival. MiR-128 was significantly reduced in chemoresistant BT-ICs enriched from breast cancer cell lines and primary breast tumors (P < 0.01), accompanied by an overexpression of Bmi-1 and ABCC5, which were identified as targets of miR-128. Ectopic expression of miR-128 reduced the protein levels of Bmi-1 and ABCC5 in BT-ICs, along with decreased cell viability (P < 0.001) and increased apoptosis (P < 0.001) and DNA damage (P < 0.001) in the presence of doxorubicin. Reduced miR-128 expression in breast tumor tissues was associated with chemotherapeutic resistance (P < 0.001) and poor survival of breast cancer patients (P < 0.05; n = 57). Reduction in miR-128 leading to Bmi-1 and ABCC5 overexpression is a stem cell-like feature of BT-ICs, which contributes to chemotherapeutic resistance in breast cancers. Ectopic expression of miR-128 sensitizes BT-ICs to the proapoptotic and DNA-damaging effects of doxorubicin, indicating therapeutic potential.
    Clinical Cancer Research 09/2011; 17(22):7105-15. · 7.84 Impact Factor
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    ABSTRACT: Ubiquitin-conjugating enzyme 9 (Ubc9), the sole conjugating enzyme for sumoylation, regulates protein function and plays an important role in tumorigenesis. Whether Ubc9 is involved in the chemoresistance of breast cancer remains unknown. In this study, we aimed to evaluate the contribution of Ubc9 in the chemoresistance of breast cancer. Immunohistochemistry (IHC) was used to examine the expression level of Ubc9. Chi-square test, Wilcoxon test, and one-way ANOVA were applied to analyze the relationship between Ubc9 expression, clinicopathologic features, and clinical response to neoadjuvant chemotherapy. The significance of variables for survival was analyzed by the Cox proportional hazards model in a multivariate analysis. Kaplan-Meier survival curves were plotted and log-rank test was performed. The proportion of Ubc9-positive cells was higher in invasive ductal carcinoma than in normal breast tissues [(48.48 ± 17.94)% vs. (5.82 ± 2.80)%, P < 0.001]. High Ubc9 expression was associated with poor differentiation (Χ² = 6.538, P = 0.038), larger tumor size (Χ² = 4.701, P = 0.030), advanced clinical stage (Χ² = 4.651, P = 0.031), lymph node metastasis (Χ² = 9.913, P = 0.010), basal-like phenotype (Χ² = 8.660, P = 0.034), and poor clinical response to neoadjuvant chemotherapy (Χ² = 11.09, P = 0.001). The expected 6-year cumulative disease-free survival rate was 87.32% in patients with low Ubc9 expression compared to 68.78% in those with high Ubc9 expression (Χ² = 4.289, P = 0.038). These data indicate that high Ubc9 expression correlates with poor response to chemotherapy and poor clinical prognosis.
    Chinese journal of cancer 09/2011; 30(9):638-44.
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    ABSTRACT: Tumor-associated macrophages (TAMs) can influence cancer progression and metastasis, but the mechanism remains unclear. Here, we show that breast TAMs abundantly produce CCL18, and its expression in blood or cancer stroma is associated with metastasis and reduced patient survival. CCL18 released by breast TAMs promotes the invasiveness of cancer cells by triggering integrin clustering and enhancing their adherence to extracellular matrix. Furthermore, we identify PITPNM3 as a functional receptor for CCL18 that mediates CCL18 effect and activates intracellular calcium signaling. CCL18 promotes the invasion and metastasis of breast cancer xenografts, whereas suppressing PITPNM3 abrogates these effects. These findings indicate that CCL18 derived from TAMs plays a critical role in promoting breast cancer metastasis via its receptor, PITPNM3.
    Cancer cell 04/2011; 19(4):541-55. · 25.29 Impact Factor
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    ABSTRACT: Trastuzumab resistance emerges to be a major issue in anti-human epidermal growth factor receptor 2 (HER2) therapy for breast cancers. Here, we demonstrated that miR-21 expression was up-regulated and its function was elevated in HER2(+) BT474, SKBR3, and MDA-MB-453 breast cancer cells that are induced to acquire trastuzumab resistance by long-term exposure to the antibody, whereas protein expression of the PTEN gene, a miR-21 target, was reduced. Blocking the action of miR-21 with antisense oligonucleotides re-sensitized the resistant cells to the therapeutic activities of trastuzumab by inducing growth arrest, proliferation inhibition, and G(1)-S cell cycle checking in the presence of the antibody. Ectopic expression of miR-21 in HER2(+) breast cancer cells confers resistance to trastuzumab. Rescuing PTEN expression with a p3XFLAG-PTEN-mut construct with deleted miR-21 targeting sequence at its 3' UTR restored the growth inhibition of trastuzumab in the resistant cells by inducing PTEN activation and AKT inhibition. In vivo, administering miR-21 antisense oligonucleotides restored trastuzumab sensitivity in the resistant breast cancer xenografts by inducing PTEN expression, whereas injection of miR-21 mimics conferred trastuzumab resistant in the sensitive breast tumors via PTEN silence. Up-regulatin of miR-21 in tumor biopsies obtained from patients receiving pre-operative trastuzumab therapy was associated with poor trastuzumab response. Therefore, miR-21 overexpression contributes to trastuzumab resistance in HER2(+) breast cancers and antagonizing miR-21 demonstrates therapeutic potential by sensitizing the malignancy to anti-HER2 treatment.
    Journal of Biological Chemistry 04/2011; 286(21):19127-37. · 4.65 Impact Factor
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    ABSTRACT: Neoadjuvant chemotherapy (NAC) is increasingly being used in breast cancer treatment. Research has revealed an elevated expression of miR-221 in adriamycinresistant MCF-7/ADR cells. This study aimed to explore the potential role of miR-221 as a biomarker for chemosensitivity in breast cancer patients who previously received NAC. The expression levels of circulating miR-221 in the plasma of 93 breast cancer patients who previously received NAC and in 32 healthy individuals were assessed. The correlations between miR-221 and clinicopathological features and chemosensitivity were also analysed. The expression level of miR-221 was significantly associated with hormone receptor (HR) status (p = 0.008). Patients with higher plasma miR-221 levels tended to be HR-negative. Patients with different miR-221 levels had significant differences in the overall response rate (p = 0.044) but not in the pathologic complete response rate (p = 0.477). Our results indicate that plasma miR-221 may be a predictive biomarker for sensitivity to NAC in breast cancer patients.
    Onkologie 01/2011; 34(12):675-80. · 1.00 Impact Factor
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    ABSTRACT: Evidence is lacking whether the number of breast tumor-initiating cells (BT-ICs) directly correlates with the sensitivity of breast tumors to chemotherapy. Here, we evaluated the association between proportion of BT-ICs and chemoresistance of the tumors. Immunohistochemical staining(IHC) was used to examine the expression of aldehyde dehydrogenase 1 (ALDH1) and proliferating cell nuclear antigen, and TUNEL was used to detect the apoptosis index. The significance of various variables in patient survival was analyzed using a Cox proportional hazards model. The percentage of BT-ICs in breast cancer cell lines and primary breast tumors was determined by ALDH1 enzymatic assay, CD44(+)/CD24(-) phenotype and mammosphere formation assay. ALDH1 expression determined by IHC in primary breast cancers was associated with poor clinical response to neoadjuvant chemotherapy and reduced survival in breast cancer patients. Breast tumors that contained higher proportion of BT-ICs with CD44(+)/CD24(-) phenotype, ALDH1 enzymatic activity and sphere forming capacity were more resistant to neoadjuvant chemotherapy. Chemoresistant cell lines AdrR/MCF-7 and SK-3rd, had increased number of cells with sphere forming capacity, CD44(+)/CD24(-) phenotype and side-population. Regardless the proportion of T-ICs, FACS-sorted CD44(+)/CD24(-) cells that derived from primary tumors or breast cancer lines were about 10-60 fold more resistant to chemotherapy relative to the non- CD44(+)/CD24(-) cells and their parental cells. Furthermore, our data demonstrated that MDR1 (multidrug resistance 1) and ABCG2 (ATP-binding cassette sub-family G member 2) were upregulated in CD44(+)/CD24(-) cells. Treatment with lapatinib or salinomycin reduced the proportion of BT-ICs by nearly 50 fold, and thus enhanced the sensitivity of breast cancer cells to chemotherapy by around 30 fold. These data suggest that the proportion of BT-ICs is associated with chemotherapeutic resistance of breast cancer. It highlights the importance of targeting T-ICs, rather than eliminating the bulk of rapidly dividing and terminally differentiated cells, in novel anti-cancer strategies.
    PLoS ONE 01/2010; 5(12):e15630. · 3.73 Impact Factor
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    ABSTRACT: To study the BRCA1 mutations in patients with early-onset breast cancer and their affected relatives in Guangdong province and explore the relationship between BRCA1 mutation and the expressions of estrogen receptor(ER), progesterone receptor(PR), HER2 and ALN. From 58 patients with early-onset breast cancer and their affected relatives, the genomic DNA was extracted from the peripheral blood mononuclear cells and the coding regions of the BRCA1 gene was amplified using polymerase chain reaction. BRCA1 gene mutations were screened by denaturing high performance liquid chromatography (DHPLC) and subsequent direct DNA sequencing. The expression of ER, PR, HER2 and ALN were detected with immunohistochemistry and their relations with the gene mutation were analyzed. Disease-related BRCA1 mutations were detected in 2 of the 58 patients, who were younger than 35 years old, including 1 with a novel splice-site mutation (IVS5-1 G-->A). No association was found between this novel mutation and the expressions of ER, PR, HER2 and ALN. The incidence of BRCA1 mutation is significantly lower in patients with early-onset breast cancer and their affected relatives in Guangdong province than in the Western populations. The novel mutation identified in BRCA1 gene may represent a mutation characteristic of the patients in Guangdong province. BRCA1 gene mutations may not have any relation with the expression of ER, PR, HER2 and ALN.
    Nan fang yi ke da xue xue bao = Journal of Southern Medical University 02/2009; 29(2):213-6.
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    ABSTRACT: Cancers may arise from rare self-renewing tumor-initiating cells (T-IC). However, how T-IC self renewal, multipotent differentiation, and tumorigenicity are maintained remains obscure. Because miRNAs can regulate cell-fate decisions, we compared miRNA expression in self-renewing and differentiated cells from breast cancer lines and in breast T-IC (BT-IC) and non-BT-IC from 1 degrees breast cancers. let-7 miRNAs were markedly reduced in BT-IC and increased with differentiation. Infecting BT-IC with let-7-lentivirus reduced proliferation, mammosphere formation, and the proportion of undifferentiated cells in vitro and tumor formation and metastasis in NOD/SCID mice, while antagonizing let-7 by antisense oligonucleotides enhanced in vitro self renewal of non-T-IC. Increased let-7 paralleled reduced H-RAS and HMGA2, known let-7 targets. Silencing H-RAS in a BT-IC-enriched cell line reduced self renewal but had no effect on differentiation, while silencing HMGA2 enhanced differentiation but did not affect self renewal. Therefore let-7 regulates multiple BT-IC stem cell-like properties by silencing more than one target.
    Cell 01/2008; 131(6):1109-23. · 31.96 Impact Factor
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    ABSTRACT: Overexpression of human epidermal growth factor receptor-2 (Her2, ErbB-2) contributes to the progression and metastasis of breast cancer, implying that Her2 gene is a suitable target of RNA interference (RNAi) for breast cancer therapy. Here, we employed plasmid-mediated expression of 2 different Her2-shRNAs (pU6-Her2shRNAs) efficiently silenced the target gene expression on Her2 expressing SKBR-3 breast cancer cells in both mRNA and protein levels. Consequently, pU6-Her2shRNA increased apoptosis and reduced proliferation of SKBR-3 cells assayed by TUNEL and MTT, respectively. In vivo, intra-tumor injection of pU6-Her2shRNA inhibited the growth of SKBR-3 tumors inoculated subcutaneously in nude mice. Furthermore, pU6-Her2shRNA synergized the tumor suppression effect of epirubicin to SKBR-3 cells in vitro and implanted subcutaneously in nude mice. Therefore, we concluded that stable silencing of Her2 gene expression with plasmid expressing shRNA may hold great promise as a novel therapy for Her2 expressing breast cancers alone or in combination with anthracycline chemotherapy.
    Biochemical and Biophysical Research Communications 09/2006; 346(3):778-85. · 2.41 Impact Factor
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    ABSTRACT: To study the feasibility of vector-mediated RNA interference for HER-2-positive breast cancer therapy. A plasmid vector capable of mediating HER-2 RNA interference was constructed, and HER-2-positive breast cancer cell line SKBR-3 was transfected with this constructed vector. The expression of HER-2 mRNA and protein was analyzed by RT-PCR and Western blotting, and the growth and apoptosis of SKBR-3 cells was analyzed after transfection. The expressions of HER-2 mRNA and HER-2 protein was downregulated in response to vector-mediated HER-2 RNA interference, which also resulted in tumor cell growth inhibition and increased number apoptotic cells. HER-2 is a good target for RNA interference and RNA interference targeting HER-2 can lead to HER-2 breast cancer cell apoptosis and growth inhibition.
    Nan fang yi ke da xue xue bao = Journal of Southern Medical University 06/2006; 26(5):570-2.
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    ABSTRACT: Toremifen is effective in reducing breast pain and does not increase the incidence of adverse events as a therapy for moderate to severe mastalgia. Design and In a double-blind randomized controlled trial, patients with moderate to severe mastalgia received toremifen citrate, 30 mg daily, or a placebo tablet for 3 menstrual cycles and were followed up for breast pain score and adverse events. The serum levels of estradiol, progesterone, and prolactin were examined before treatment and correlated with the response rate to toremifen treatment. Seventy-two (69.2%) of 104 patients receiving toremifen and 29 (31.9%) of 91 receiving placebo responded to the treatment, with reduction in breast pain score of more than 50% (P<.001). Among the patients with cyclical mastalgia, the response rate for toremifen was 76.7% (59/77), whereas the response rate for placebo was 34.8% (23/66; P<.001). In contrast, the response rate of patients with noncyclical mastalgia was 48.1% (13/27) for toremifen and 24.0% (6/25) for placebo (P = .09). Adverse events were observed in 44 (42.9%) of 104 patients receiving placebo and 46 (50.5%) of 91 patients receiving toremifen (P = .45). A positive correlation between baseline breast pain score and serum estradiol level was observed in patients with cyclical mastalgia (r = 0.35, P = .003). Toremifen effectively relieves moderate and severe cyclical mastalgia and tends to exert a positive therapeutic effect on noncyclical mastalgia. In addition, toremifen therapy does not increase the incidence of intolerable adverse event. Therefore, it is a feasible therapy for mastalgia, especially cyclical mastalgia.
    Archives of Surgery 02/2006; 141(1):43-7. · 4.10 Impact Factor
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    ABSTRACT: Psychological distress reduces the efficacy of chemotherapy in breast cancer patients. The mechanism may be related to the altered neuronal or hormonal secretions during stress. Here, we reported that adrenaline, a hormone mediating the biological activities of stress, upregulates mdr1 gene expression in MCF-7 breast cancer cells via alpha(2)-adrenergic receptors in a dose-dependent manner. Mdr1 upregulation can be specifically inhibited by pretreatment with mdr1-siRNA. Consequently, adrenergic stimulation enhances the pump function of P-glycoprotein and confers resistance of MCF-7 cells to paclitaxel. In vivo, restraint stress increases mdr1 gene expression in the MCF-7 cancers that are inoculated subcutaneously into the SCID mice and provokes resistance to doxorubicin in the implanted tumors. The effect can be blocked by injection of yohimbine, an alpha(2)-adrenergic inhibitor, but not by metyrapone, a corticosterone synthesis blocker. Therefore, we conclude that breast cancers may develop resistance against chemotherapeutic drugs under psychological distress by over-expressing mdr1 via adrenergic stimulation.
    Biochemical and Biophysical Research Communications 05/2005; 329(3):888-97. · 2.41 Impact Factor
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    ABSTRACT: Breast cancer is the most common malignant disease of women. Pathologic response of breast cancer to chemotherapy has a great prognostic importance. Glutathion S Transferases (GSTs) might detoxify chemotherapeutic drugs within the cancer cells, thus contributing to chemotherapy resistance. The pi isoenzyme of GSTs seems to be of great relevance. Thus, we hypothesized that GSTpi expression in cancer biopsy can be a prognostic indicator for resistance to chemotherapy. To test this hypothesis, we evaluated before and after chemotherapy, tumor size, apoptosis of tumor cells with TUNEL assay, and proliferation of tumor cells by determining PCNA expression in biopsy samples, or in the surgically removed tumor tissue of GSTpi (-), and GSTpi (+) cases. GSTpi immunoreactivity was determined in 42 female patients with breast cancer. Patients were divided into two groups according to the expression of GSTpi in the pre-treatment biopsy specimen: (+) (n = 22) and (n = 20) samples were analyzed. Surgery was performed 2 weeks after a single intravenous injection of the chemotherapeutic drugs [5-fluorouracil, adriamycin, mitomycin (FAM protocol)]. Pre-chemotherapy values of tumor size, apoptosis, or proliferation did not differ between GSTpi (-) and (+) samples. Chemotherapy significantly inhibited tumor growth, and cell proliferation, and induced apoptosis in GSTpi (-) cases. However, these effects were significantly reduced in GSTpi (+) patients. These results suggest, that the presence of GSTpi in breast cancer tissue is a bad prognostic indicator, and these tumors are largely resistant to chemotherapy. Thus, GSTpi might be important in inactivating one or more of the chemotherapeutic agents used in this treatment.
    Journal of Surgical Research 08/2003; 113(1):102-8. · 2.02 Impact Factor
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    ABSTRACT: Background Breast cancer is the most common malignant disease of women. Pathologic response of breast cancer to chemotherapy has a great prognostic importance. Glutathion S Transferases (GSTs) might detoxify chemotherapeutic drugs within the cancer cells, thus contributing to chemotherapy resistance. The pi isoenzyme of GSTs seems to be of great relevance. Thus, we hypothesized that GSTpi expression in cancer biopsy can be a prognostic indicator for resistance to chemotherapy. To test this hypothesis, we evaluated before and after chemotherapy, tumor size, apoptosis of tumor cells with TUNEL assay, and proliferation of tumor cells by determining PCNA expression in biopsy samples, or in the surgically removed tumor tissue of GSTpi (−), and GSTpi (+) cases.
    Journal of Surgical Research - J SURG RES. 01/2003; 113(1):102-108.