[Show abstract][Hide abstract] ABSTRACT: Numerous studies have yielded inconclusive results regarding the relationship between anti-apoptotic protein Bcl-2 expression and the sensitivity to chemotherapy in the patients with breast cancer. The purpose of the current study was therefore to elaborate their relationship.Methods, findings: A total of 23 previously published eligible studies involving 2,467 cases were identified and included in this meta-analysis. Negative Bcl-2 expression was associated with good chemotherapy response in breast cancer patients (total objective response [OR]: risk ratio [RR] = 1.16, 95% confidence interval [CI] = 1.02-1.32, p = 0.026; total complete response [CR]: RR = 1.67, 95% CI = 1.24-2.24, p = 0.001; pathological CR: RR = 1.92, 95% CI = 1.38-2.69, p < 0.001). In further stratified analyses, this association remained for sub-groups of response in neoadjuvant chemotherapy setting, especially pathological CR. Besides, negative Bcl-2 expression was significantly associated with good OR and pathological CR in anthracycline-based chemotherapy subgroup. Furthermore, there were significant links between negative Bcl-2 expression and taxane-based chemotherapy with pathological CR, but not OR.
The results of the present meta-analysis suggest that Bcl-2 expression is a predictive factor for chemotherapy sensitivity in breast cancer patients. They could also potentially benefit further clinical treatment for breast cancers.
Journal of Experimental & Clinical Cancer Research 12/2013; 32(1):105. · 3.07 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The earlier studies have shown that Fascin1 (FSCN1), the actin bundling protein, is over-expressed in colorectal cancers, and is associated with cancer cell progression. Here, we aimed to understand the molecular mechanisms regulating FSCN1 expression by focusing on mammalian target of rapamycin (mTOR) signaling and its regulator microRNA-451. We found that microRNA-451 was over-expressed in multiple colorectal cancer tissues, and its expression was correlated with mTOR complex 1 (mTORC1) activity and FSCN1 expression. In cultured colorectal cancer HT-29 cells, knockdown of FSCN1 by RNAi inhibited cell migration and proliferation. Activation of mTORC1 was required for FSCN1 expression, HT-29 cell migration and proliferation, as RAD001 and rapamycin, two mTORC1 inhibitors, suppressed FSCN1 expression, HT-29 cell migration and proliferation. Meanwhile, forced activation of AMP-activated protein kinase (AMPK), the negative regulator of mTORC1, by its activators or by the genetic mutation, inhibited mTORC1 activation, FSCN1 expression, cell migration and proliferation. In HT-29 cells, we found that over-expression of microRNA-451 inhibited AMPK activation, causing mTORC1 over-activation and FSCN1 up-regulation, cells were with high migration ability and proliferation rate. Significantly, these effects by microRNA-451 were largely inhibited by mTORC1 inhibitors or the AMPK activator AICAR. On the other hand, knockdown of miRNA-451 by the treatment of HT-29 cells with miRNA-451 antagomir inhibited mTORC1 activation and FSCN1 expression. The proliferation and migration of HT-29 cells after miRNA-45 knockdown were also inhibited. Our results suggested that the over-expressed microRNA-451 in colon cancer cells might inhibit AMPK to activate mTORC1, which mediates FSCN1 expression and cancer cell progression.
[Show abstract][Hide abstract] ABSTRACT: Here we report that activation of AMP-activated protein kinase (AMPK) mediates plumbagin-induced apoptosis and growth inhibition in both primary cultured human colon cancer cells and cell lines. Knocking-down of AMPKα by the target shRNA significantly inhibits plumbagin-induced cytotoxicity in cultured colon cancer cells, while forced activation of AMPK by introducing a constitutively active AMPK (CA-AMPK), or by the AMPK activator, inhibits HT-29 colon cancer cell growth. Our Western-blots and immunoprecipitation (IP) results demonstrate that plumbagin induces AMPK/ Apoptosis signal regulating kinase 1 (ASK1)/ TNF receptor-associated factor 2 (TRAF2) association to activate pro-apoptotic c-Jun N-terminal kinases (JNK)-p53 signal axis. Further, after plumbagin treatment, activated AMPK directly phosphorylates Raptor to inhibit mTOR complex 1 (mTORC1) activation and Bcl-2 expression in colon cancer cells. Finally, we found that exogenously-added short-chain ceramide (C6) enhances plumbagin-induced AMPK activation and facilitates cell apoptosis and growth inhibition. Our results suggest that AMPK might be the key mediator of plumbagin's anti-tumor activity.
[Show abstract][Hide abstract] ABSTRACT: Many epidemiological studies have found that leptin correlates to body fat extent and breast cancer. Leptin exerts its physiological action through the leptin receptor (LEPR). However, published data on the association between LEPR alleles and breast cancer occurrence have led to in contradictory results. A total of 10 studies were identified to the meta-analysis, including 4,644 cases and 5,485 controls for LEPR rs1137101 polymorphism, 5 studies with 2,759 cases and 4,464 controls for rs1137100 polymorphism, and 2 studies for rs8051542, rs8051542, and rs8051542 polymorphisms. The pooled odds ratios (OR) with 95 % confidence intervals (CI) for breast cancer risk associated with LEPR genotypes were estimated. Elevated breast cancer risk was associated with LEPR rs1137101 polymorphism when all studies were pooled in the meta-analysis (allele contrast model: OR = 0.71, 95 % CI = 0.551-0.997). In the stratified analysis by ethnicity, significantly increased risks were also found among Asians for allele contrast model (OR 0.414, 95 % CI 0.312-0.550) and dominant model (OR 0.537, 95 % CI 0.370-0.781); for Africans, significantly increased risks were also found for allele contrast model (OR 0.716, 95 % CI 0.595-0.861), homozygote codominant (OR 0.537, 95 % CI 0.370-0.781) and dominant model (OR 1.595, 95 % CI 1.207-2.108). And significantly elevated breast cancer risk was associated with LEPR rs1137100 polymorphism for allele contrast (OR = 0.666, 95 % CI = 0.603-0.720) and homozygote codominant models (OR = 0.344, 95 % CI = 0.282-0.421). For LEPR rs8179183, rs4655537, and rs3762274 polymorphisms, no significant associations were detected in all comparison models. This pooled analysis suggested that rs1137101 and rs1137100 polymorphisms were significantly correlated with breast cancer risk and the A allele of LEPR rs1137101 variant and the G allele of LEPR rs1137100 variant were low-penetrant risk factors for developing breast cancer. Further, no significant associations existed between LEPR rs8179183, rs4655537, and rs3762274 polymorphisms and risk of breast cancer.
Breast Cancer Research and Treatment 09/2012; 136(1):231-9. · 4.47 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Our study shows that coadministration of curcumin and an orally bioactive alkylphospholipid perifosine results in a significant increase in colorectal cancer cell apoptosis and a marked inhibition of cell growth both in vitro and in vivo. This novel combinatorial regimen leads to changes of multiple cell signaling pathways including inactivation of Akt and nuclear factor-κB as well as activation of c-Jun N-terminal kinases and endoplasmic reticulum stress. Further, perifosine and curcumin synergistically increase intracellular level of reactive oxygen species and ceramide, and downregulate the expression of cyclin D1 and Bcl-2 in colorectal cancer cells. These changes at molecular level together account for the cancer cell apoptosis and growth inhibition. We conclude that perifosine sensitizes colorectal cancer cells to curcumin by modulating multiple signaling pathways. Adding perifosine with curcumin may represent an effective therapy regimen against colorectal cancers, and possible other aggressive tumors.
International Journal of Cancer 03/2012; 131(11):2487-98. · 6.20 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Numerous studies have yielded inconsistent results regarding the relationship between p53 status and the response to neoadjuvant radiation-based therapy in patients with rectal cancer. We conducted a meta-analysis to clarify the relationship between p53 status and response to radiation-based therapy in rectal cancer.
A total of 30 previously published eligible studies including 1,830 cases were identified and included in this meta-analysis. Wild-type form of p53 status (low expression of p53 protein and/or wild-type p53 gene) was associated with pathologic response in rectal cancer patients who received neoadjuvant radiation-based therapy (good response: risk ratio [RR] = 1.30; 95% confidence intervals [CI] = 1.14-1.49; p<0.001; complete response RR = 1.65; 95% CI = 1.19-2.30; p = 0.003; poor response RR = 0.85; 95% CI = 0.75-0.96; p = 0.007). In further stratified analyses, this association remained for sub-groups of good and poor response in neoadjuvant radiotherapy (RT) setting, good and complete response in chemoradiotherapy (CRT) setting. And the association between response and the presence of p53 gene mutations was stronger than that between response and protein positivity.
The results of the present meta-analysis indicate that P53 status is a predictive factor for response in rectal cancer patient undergoing neoadjuvant radiation-based therapy.
PLoS ONE 01/2012; 7(9):e45388. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Numerous studies have yielded inconclusive results regarding the relationship between tumor suppressor protein TP53 overexpression and/or TP53 gene mutations and the response to neoadjuvant chemotherapy in patients with breast cancer. The purpose of the current study was therefore to evaluate the relationship between TP53 status and response to chemotherapy in breast cancer.
A total of 26 previously published eligible studies including 3,476 cases were identified and included in this meta-analysis. TP53 status (over expression of TP53 protein and/or TP53 gene mutations) was associated with good response in breast cancer patients who received neoadjuvant chemotherapy (total objective response: risk ratio [RR]= 1.20, 95% confidence interval [CI]= 1.09-1.33, p<0.001; pathological objective response: RR = 1.37, 95% CI = 1.20-1.57, p<0.01; total complete response: RR = 1.33, 95% CI = 1.15-1.53, p<0.001; pathological complete response: RR = 1.45, 95% CI = 1.25-1.68, p<0.001). In further stratified analyses, this association also existed among the studies using anthracycline-based neoadjuvant chemotherapy, and the association between response and the presence of gene alterations was stronger than that between response and immunohistochemistry positivity.
The results of the present meta-analysis suggest that TP53 status is a predictive factor for response in breast cancer patients undergoing neoadjuvant chemotherapy. Further larger and well-designed prospective studies are required to evaluate the predictive role of TP53 status in clinical practice.
PLoS ONE 01/2012; 7(6):e39655. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The molecular basis for induction of apoptosis in melanoma cells by vincristine remains unknown. Here we tested the potential involvement of AMP-activated protein kinase (AMPK) in this process. We found for the first time that vincristine induces AMPK activation (AMPKα, Thr 172) and Acetyl-CoA carboxylase (ACC, Ser 79) (a downstream molecular target of AMPK) phosphorylation in cultured melanoma cells in vitro. Reactive oxygen species (ROS) dependent LKB1 activation serves as the upstream signal for AMPK activation. AMPK inhibitor (compound C) or AMPKα siRNA knockdown inhibits vincristine induced B16 melanoma cell apoptosis, while AMPK activator 5-aminoimidazole-4-carboxamide-1-β-riboside (AICAR) enhances it. AMPK activation is involved in vincristine induced p53 phosphorylation and stabilization, the latter is known to mediate melanoma cell apoptosis. Further, activation of AMPK by vincristine inhibits mTOR Complex 1 (mTORC1) in B16 melanoma cells, which serves as another important mechanism to induce melanoma cell apoptosis. Our study provides new insights into understanding the cellular and molecular mechanisms of vincristine induced cancer cell death/apoptosis. We suggest that combining AMPK activator AICAR with vincristine may have potential to be used as a new therapeutic intervention against melanoma.
Journal of Cellular Physiology 07/2011; 226(7):1915-25. · 4.22 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Published data on the association between mitogen-activated protein kinase kinase kinase 1 (MAP3K1) gene rs889312 polymorphism and breast cancer risk are inconclusive. To derive a more precise estimation of the relationship, a meta-analysis was performed. Crude ORs with 95% CIs were used to assess the strength of association between them. A total of seven eligible articles including 26,015 cases and 33,962 controls based on the search criteria were involved in this meta-analysis. We observed that the MAP3K1 rs889312 polymorphism was significantly correlated with breast cancer risk from the fixed effects model when all studies were pooled into the meta-analysis (the allele contrast model: OR 1.09, 95% CI 1.07-1.12; the homozygote codominant: OR 1.22, 95% CI 1.15-1.29; the heterozygote codominant: OR 1.07, 95% CI 1.04-1.11; the dominant model: OR 1.10, 95% CI 1.06-1.13; the recessive model: OR 1.18, 95% CI 1.12-1.25). No significant association was found in the BRCA1 mutation carriers in all genetic models. When stratified by BRCA2 mutation carriers status, statistically significantly elevated risk was found in this meta-analysis (C vs. A: OR 1.12, 95% CI 1.01-1.23; CC vs. AA: OR 1.35, 95% CI 1.06-1.71; the recessive model: OR 1.31, 95% CI 1.05-1.65). There was no evidence for significant association between MAP3K1 rs889312 polymorphism and breast cancer risk in BRCA1 and BRCA2 positive cohort for all comparison models. In conclusion, this meta-analysis suggests that the MAP3K1 rs889312 C allele is a low-penetrant risk factor for developing breast cancer, and there is limited evidence to indicate that MAP3K1 rs889312 polymorphism is associated with increased risk of breast cancer in BRCA1 mutation carriers.
Breast Cancer Research and Treatment 04/2011; 126(3):663-70. · 4.47 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Trinucleotide repeat containing 9 (TNRC9) is a gene located at chromosome 16q12. Although of an uncertain function, it is a newly described risk factor for breast cancer. It contains a putative high-mobility group box motif, suggesting its possible role as transcription factor; it has been implicated in breast cancer metastasis. Published studies on the association between TNRC9 polymorphisms and breast cancer risk remain inconclusive, and a meta-analysis is required to verify the association. This pioneering research performed a meta-analysis of eight studies comprising a total of 25,828 cases and 36,177 controls. Significantly elevated breast cancer risk was associated with TNRC9 rs3803662 polymorphism when all studies were pooled in the meta-analysis (T vs. C allele contrast model: OR 1.18, 95% CI 1.09-1.28; TT vs. CC homozygote codominant model: OR 1.26, 95% CI 1.02-1.55; TT vs. CC+CT recessive model: OR 1.23, 95% CI 1.06-1.42). For TNRC9 rs12443621 polymorphism, no significant association was detected in all genetic models. For TNRC9 rs12443621 polymorphism, meanwhile, no significant association was observed in all comparison models. Conclusively, this meta-analysis suggests that TNRC9 rs3803662 polymorphism was significantly correlated with breast cancer risk and the variant T allele of TNRC9 rs3803662 polymorphism is a low-penetrant risk factor for developing breast cancer. There is no significant association between TNRC9 rs12443621 and rs8051542 polymorphisms and risk of breast cancer in current literature.
Breast Cancer Research and Treatment 02/2011; 126(1):177-83. · 4.47 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Epidemiological studies have evaluated the association between ataxia telangiectasia mutated (ATM) gene polymorphisms and breast cancer risk. However, published data are still inconclusive. We performed a meta-analysis for the first time, based on currently available evidence, by searching PubMed, ISI Web of Knowledge, and Embase databases to derive a more precise assessment of the relationship. Following the inclusion and exclusion criteria, nine publications were included in this meta-analysis. Of these studies, one had a deviation from the Hardy-Weinberg equilibrium (HWE) at a statistical significance level of 0.01 in controls, and another two had no available data for HWE. We observed that the ATM 5557G>A polymorphism was significantly correlated with breast cancer risk when all studies were pooled into the meta-analysis (recessive model: odds ratio, OR = 0.67; 95% confidence interval (CI) 0.51-0.89). For the ATM IVS38-8T>C polymorphism, no significant association was found in the allele contrast, heterozygote codominant, and dominant models. There were no available data to perform this meta-analysis in the homozygote codominant and recessive models. For the ATM IVS1+19A>T polymorphism, a significant association with breast cancer risk was found in the allele contrast model (C vs. T: OR = 1.60; 95% CI 1.02-2.52). For the IVS34+60G>A polymorphism, no significant association was found in the allele contrast, codominant, dominant, and recessive models. Egger's test did not suggest any evidence of publication bias (P = 0.47 for the recessive model). In conclusion, there is limited evidence to indicate that ATM polymorphisms are associated with increased risk of breast cancer.
Breast Cancer Research and Treatment 02/2011; 126(1):141-8. · 4.47 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The aim of our meta-analysis was to assess the association between UGT1A7 polymorphisms and cancer risk. Case?control studies containing available polymorphic alleles (UGT1A7*1,*2,*3, and*4) and genotypes categorized according to enzymatic activity (High, Intermediate, and Low) were chosen to assess this association. Twenty-one case?control studies were identified. Meta-analysis indicated that UGT1A7 had a significant effect on cancer risk. In subgroup analysis, a significantly increased risk was associated with East Asians, hepatocellular cancer, and colorectal cancer. This meta-analysis suggested that there is a cancer risk associated with UGT1A7*3, Intermediate, and Low activity UGT1A7 genotypes, which is most evident in Asian individuals.
Cancer Investigation 01/2011; 29(10):645-54. · 2.24 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Previous epidemiological studies have evaluated the association between the ABCB1 polymorphism and the risk of breast cancer with conflicting results. Hence, we conducted a meta-analysis of the ABCB1 gene and risk of breast cancer to obtain the most reliable estimate of the association. PubMed, Embase, and Web of Science databases were searched. A total of eight studies including 3,829 cases and 6,193 controls were identified. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were extracted and pooled to assess the strength of associations between the ABCB1 C3435T and rs2214102 G>A polymorphisms and risk of breast cancer. Of these studies, only one deviated from Hardy-Weinberg equilibrium. Summary estimates indicated that the ABCB1 C3435T polymorphism was not associated with increased risk of breast cancer in the allele contrast model (T vs. C, pooled OR = 1.15; 95% CI = 0.89-1.48); the co-dominant model (CT vs. CC, OR = 1.12 [0.86-1.46] and TT vs. CC, OR = 1.30 [0.79-2.15]); the dominant model (OR = 0.80 [0.63-1.02]; and the recessive model (OR = 0.83 [0.57-1.22]). In the sensitivity analysis by ethnicity, no statistically significant associations were detected in Asians. However, in Caucasian women the T allele contrast model and the TT genotype were each associated with increased risk: T vs. C, pooled OR (95% CI) = 1.26 (1.04-1.52) and TT vs. CC, OR = 1.48 (1.04-2.11). Accordingly, the dominant model yielded statistically significant results (pooled OR = 0.71, 95% CI: 0.52-0.96) but not with the allele contrast model or the co-dominant model. There was evidence of publication bias (P = 0.02 for recessive model). In conclusion, there is limited evidence to indicate that the ABCB1 C3435T and rs2214102 G>A polymorphisms are associated with increased risk of breast cancer.
Breast Cancer Research and Treatment 01/2011; 125(2):537-43. · 4.47 Impact Factor