Xiaoming Zha

Downregulation of miR-106b induced breast cancer cell invasion and motility in association with overexpression of matrix metalloproteinase 2

Breast cancer (BC) is one of the most common cancers in women, and it can often metastasize to the bone. The mechanism of BC bone metastasis remains unclear and requires in‐depth investigation. In a previous study, we found the expression of matrix metalloproteinase 2 (MMP2) to be significantly more pronounced at metastatic bone sites than at orthotopic sites. MicroRNA expression profiling showed miR‐106b to be markedly downregulated during BC bone metastasis. However, the specific manner in which MMP2 and miR‐106b are involved in the BC bone metastasis is still unclear. In the present study, we found MMP2 expression in orthotopic tumor tissue to be related to the risk of bone metastasis in BC patients. MiR‐106b levels in orthotopic tumor tissue showed a negative correlation with MMP2 expression and breast cancer bone metastasis. MMP2 was shown to be a direct target of miR‐106b. Both gain‐ and loss‐of‐function studies showed that MMP2 could promote the migration and invasion of BC cells and that miR‐106b could suppress both. The blockage of MMP2 by RNA interference mimicked the anti‐migration and anti‐invasion effects of miR‐106b, and introduction of MMP2 antagonized the function of miR‐106b. MMP2 was also found to regulate the ERK signaling cascade and so adjust the bone microenvironment to favor osteoclastogenesis and bone metastasis. These results suggest that MMP2 upregulation plays an important role in BC bone metastasis through ERK pathways, and miR‐106b directly regulates MMP2 expression. The miR‐106b/MMP2/ERK pathway may be a promising therapeutic target for inhibiting BC bone metastasis.

Intraoperative ultrasound guidance is associated with clear lumpectomy margins for breast cancer: a systematic review and meta-analysis.

Purpose Margin status is one of the most important predictors of local recurrence after breast conserving surgery (BCS). Intraoperative ultrasound guidance (IOUS) has the potential to improve surgical accuracy for breast cancer. The purpose of the present meta-analysis was to determine the efficacy of IOUS in breast cancer surgery and to compare the margin status to that of the more traditional Guide wire localization (GWL) or palpation-guidance. Methods We searched the database of PubMed for prospective and retrospective studies about the impact of IOUS on margin status of breast cancer, and a meta-analysis was conducted. Results Of the 13 studies included, 8 were eligible for the impact of IOUS on margin status of non-palpable breast cancers, 4 were eligible for palpable breast cancers, and 1 was for both non-palpable and palpable breast cancers. The rate of negative margins of breast cancers in IOUS group was significantly higher than that in control group without IOUS (risk ratio (RR)  = 1.37, 95% confidence interval (CI)  = 1.18–1.59 from 7 prospective studies, odds ratio (OR)  = 2.75, 95% CI  = 1.66–4.55 from 4 retrospective studies). For non-palpable breast cancers, IOUS-guidance enabled a significantly higher rate of negative margins than that of GWL-guidance (RR  = 1.26, 95% CI  = 1.09–1.46 from 6 prospective studies; OR  = 1.45, 95% CI  = 0.86–2.43 from 2 retrospective studies). For palpable breast cancers, relative to control group without IOUS, the RR for IOUS associated negative margins was 2.36 (95% CI  = 1.26–4.43) from 2 prospective studies, the OR was 2.71 (95% CI  = 1.25–5.87) from 2 retrospective studies. Conclusion This study strongly suggests that IOUS is an accurate method for localization of non-palpable and palpable breast cancers. It is an efficient method of obtaining high proportion of negative margins and optimum resection volumes in patients undergoing BCS.

MDM2 Promotes Invasion and Metastasis in Invasive Ductal Breast Carcinoma by Inducing Matrix Metalloproteinase-9

The molecular mechanisms that underpin invasive ductal breast cancer (IDC) invasion and metastasis are incompletely understood. The oncogene, mouse double minute 2 (MDM2), has been implicated in the pathogenesis of numerous cancers, where it stimulates the expression of matrix metalloproteinase 9 (MMP9), an important enzyme in the breakdown of the extracellular matrix. However, its role in breast cancer remains poorly understood. This study assessed the clinical significance of MDM2 expression in IDC and used in vitro expression assays to determine the molecular roles of MDM2. Immunohistochemical staining for MMP9 and MDM2 was performed using archived tumor blocks from 321 women who underwent surgical resection for IDC at the First Affiliated Hospital of Nanjing Medical University, China between January 2002 and December 2003. MCF-7 and MDA-MD-231 cell lines were transfected with siRNA targeted against MDM2, or MDM2 was overexpressed using transiently expressed vectors. The invasion, cell migration and proteolytic capabilities of cells that over- or underexpressed MDM2 was then assessed and compared against control cells, in addition to the consequent effects on MMP9 expression using RT-PCR. In vivo, 54.9% and 49.6% of samples were positive for MMP9 and MDM2 expression, respectively, and their expression was significantly correlated (r2 = 0.171, P = 0.012). Moreover, MDM2 expression was markedly correlated with disease-free survival (HR 2.56, 95% CI 1.02–6.40, P = 0.038). In vitro, MDM2 overexpression significantly enhanced cell invasion, migration and proteolysis compared with control cells, and the converse effects were observed after MDM2-siRNA treatment. MDM2 overexpression induced MMP9 expression in a dose-dependent manner. Taken together, these results suggest that high levels of MDM2 are associated with a poorer prognosis in IDC. This might result from increased tumor invasiveness due to enhanced MMP9 expression causing increased extracellular matrix breakdown.

Reproductive factors and breast cancer risk among BRCA1 or BRCA2 mutation carriers: Results from ten studies

Although reproductive factors are among the most well-established risk factors for breast cancer in the general population, it is still a matter for debate whether these factors act as risk modifiers among BRCA1 or BRCA2 mutation carriers. This meta-analysis is the first to be performed to determine the relationship between reproductive factors and breast cancer risk among BRCA1 and BRCA2 mutation carriers. We searched the PubMed database up to February 2013. A total of ten studies met the inclusion criteria. The results showed that the reproductive factors may be associated with breast cancer risk only among BRCA1 mutation carriers. No association was found between parity and breast cancer risk. Compared with women at the youngest age in the first-birth category, women in the oldest age category were at a 38% lower risk of breast cancer (RR=0.62, 95%CI=0.45-0.85). Breastfeeding for at least 1 or 2 years was associated with a 37% reduction in breast cancer risk (RR=0.63, 95%CI=0.46-0.86). Women at the oldest age in the menarche category were at a 34% lower risk of breast cancer (RR=0.66, 95%CI=0.53-0.81) than women in the youngest age category. However, none of the reproductive factors were associated with breast cancer risk among BRCA2 mutation carriers. In conclusion, late age at first birth, breastfeeding, and late age at menarche protect against breast cancer in BRCA1 mutation carriers only. Further studies are needed to explore the mechanisms.

Phenformin Induces Cell Cycle Change, Apoptosis, and Mesenchymal-Epithelial Transition and Regulates the AMPK/mTOR/p70s6k and MAPK/ERK Pathways in Breast Cancer Cells

Breast cancer remains a world-wide challenge, and additional anti-cancer therapies are still urgently needed. Emerging evidence has demonstrated the potent anti-tumor effect of biguanides, among which phenformin was reported to potentially be a more active anti-cancer agent than metformin. However, little attention has been given to the role of phenformin in breast cancer. In this study, we reveal the role of phenformin in cell death of the MCF7, ZR-75-1, MDA-MB-231 and SUM1315 breast cancer cell lines. The respective IC50 values of phenformin in MCF7, ZR-75-1, MDA-MB-231 and SUM1315 cells were 1.184±0.045 mM, 0.665±0.007 mM, 2.347±0.010 mM and 1.885±0.015 mM (mean± standard error). Phenformin induced cell cycle change and apoptosis in breast cancer cells via the AMPK/mTOR/p70s6k and MAPK/ERK pathways. Interestingly, phenformin induced MET (mesenchymal-epithelial transition) and decreased the migration rate in breast cancer cell lines. Furthermore, our results suggest that phenformin inhibits breast cancer cell metastasis after intracardiac injection into nude mice. Taken together, our study further confirms the potential benefit of phenformin in breast cancer treatment and provides novel mechanistic insight into its anti-cancer activity in breast cancer.

Regulation of CD44 expression by tumor necrosis factor-α and its potential role in breast cancer cell migration

CD44 molecule plays critical role in distant malignant metastasis. It is expressed in standard form (CD44s) or variant form (CD44v). Tumor necrosis factor-α (TNF-α) is highly expressed in the cancer microenvironment. TNF-α was reported to modulate CD44 expression in several kinds of cancer. However, little is known about pathological role of TNF-α in breast cancer (BC) cells. In the current investigation, we investigated the effect of TNF-α on BC cells (MCF-7 and MDA-MB-231) viability, CD44 expression, and in vitro migration. We found that TNF-α down-regulated CD44s expression, up-regulated CD44v3 and CD44v6 expression through JNK pathway in MCF-7 cells. In MDA-MB-231 cells, TNF-α up-regulated CD44s, CD44v3 and CD44v6 expression via p38 pathway. These data indicate important role of CD44 molecule in BC pathology.

The Risk of Amenorrhea Is Related to Chemotherapy-Induced Leucopenia in Breast Cancer Patients Receiving Epirubicin and Taxane Based Chemotherapy

Background Chemotherapy-induced amenorrhea (CIA) is common in young breast cancer patients. The incidence of CIA associated with regimens involving epirubicin and taxane was not well known. Furthermore, previous studies suggested leucopenia and amenorrhea may reflect inter-individual variations in pharmacokinetics. The purpose of this study was to investigate the association between leucopenia after first cycle of chemotherapy and CIA in young breast cancer patients receiving epirubicin and taxane based chemotherapy. Furthermore, the incidence of CIA was also assessed. Methodology and Principal Findings Between October 2008 and March 2010, 186 consecutive premenopausal patients, treated with epirubicin and taxane based chemotherapy, were recruited. Information about CIA was collected by telephone and out-patient clinic. Of these 186 patients, data from 165 patients were included and analyzed. Of all 165 patients, CIA occurred in 72 patients (43.64%). In multivariate analysis, age older than 40 y (OR: 16.10, 95% CI: 6.34–40.88, P<0.001) and previous childbearing (OR: 3.17, 95% CI: 1.06–9.47, P = 0.038) were significantly associated with probability of CIA. Compared to patients treated without taxane, patients treated with taxane-contained regimens did not have a significantly higher rate of CIA (P>0.05). The rate of CIA in leucopenia group (52.56%) was significantly higher than that in normal leukocyte group (34.62%) (P = 0.024). In patients treated with a FEC regimen (cyclophosphamide, epirubicin and 5-fluorouracil), the rate of CIA in leucopenia group (59.57%) was significantly higher than that in normal leukocyte group (36.84%) (P = 0.037). Conclusions Age at diagnosis and previous childbearing were both found to significantly increase the risk of CIA, whereas additional taxane was not associated with increased rate of CIA. Importantly, leucopenia after first cycle of chemotherapy was associated with increased risk of CIA, which suggested that leucopenia may be an early predictor of chemotherapy-induced infertility.

Evaluation of the Therapeutic Efficacy of Sequential Therapy Involving Percutaneous Microwave Ablation in Combination with 131I-Hypericin Using the VX2 Rabbit Breast Solid Tumor Model

Purpose Combination of percutaneous microwave ablation (PMWA) and intravenous injection of 131I-hypericin(IIIH) may bear potential as a mini-invasive treatment for tumor. The objective of this study was to assess the effect of PMWA and IIIH in breast tumor growth. Methods Ten New Zealand White rabbits bearing VX2 breast carcinomas were randomly divided into two groups (each 5 examples) and processed using PMWA followed by IIIH and IIIH alone. The IIIH activity was evaluated using planar scintigraphy, autoradiography and biodistribution analysis. The maximum effective safe dose of IIIH was found through 48 rabbits with VX2 breast tumor, which were randomized into six groups (n=8 per group). Subsequently, a further 75 rabbits bearing VX2 breast solid tumors were randomly divided into five groups (each 15 examples) and treated as follows: A, no treatment group; B, PMWA alone; C, IIIH alone; D, PMWA+IIIH×1 (at 8 h post-PMWA); and E, PMWA+IIIH×2 (at 8 h and at 8 days post-PMWA). The therapeutic effect was assessed by measurement of tumor size and performation of positron emission tomography/computed tomograph (PET/CT) scans, liver and renal function tests and Kaplan-Meier survival analysis. Results The planar scintigraphy findings suggested a significant uptake of 131I in necrotic tumor tissue. The autoradiography gray scales indicated higher selective uptake of IIIH by necrotic tissue, with significant differences between the groups with and those without necrotic tumor tissue (P<0.05). The maximum effective safe dose of IIIH was 1mCi/kg. The PET/CT scans and tumor size measurement suggested improvements in treatment groups at all time points (P<0.01). Significant differences were detected among Groups A, B, D and E (P<0.05). Lower levels of lung metastasis were detected in Groups D and E (P<0.05). There were no abnormalities in liver and renal functions tests or other reported side effects. Conclusion IIIH exhibited selective uptake by necrotic tumor tissue. Sequential therapy involving PMWA+IIIH was successfully inhibiting tumor growth and prolonging survival.

Risk of breast cancer and family history of other cancers in first-degree relatives in Chinese women: a case control study.

BackgroundFew studies have systematically reported the relationship between the risk of breast cancer and family history of other cancers. This study was designed to systematically determine the relationship between breast cancer risk and family history of other cancers in first-degree relatives.MethodsBetween January 2006 and June 2011, 823 women diagnosed with breast cancer were included, and age-matched women diagnosed with benign breast disease were selected as controls. Family history of other cancers in first-degree relatives was recorded by trained reviewers. Multivariate logistic regression was applied to analyze the relationships.ResultsA family history of esophagus cancer (OR: 2.70, 95% CI: 1.11 – 6.57), lung cancer (OR: 2.49 95% CI: 1.10 – 5.65), digestive system cancer (OR: 1.79, 95% CI: 1.14 – 2.79) and any cancer (OR: 2.13, 95% CI: 1.49 – 3.04) in first-degree relatives was directly associated with increased breast cancer risk. In subgroup analysis, the risk of hormone receptor positive breast cancer was increased in subjects with a family history of lung cancer (OR: 3.37, 95% CI: 1.45 – 7.82), while the risk of hormone receptor negative breast cancer was increased in subjects with a family history of esophagus cancer (OR: 6.19, 95% CI: 2.30 – 16.71), uterus cancer (OR: 6.92, 95% CI: 1.12 – 42.89), digestive tract cancer (OR: 2.05, 95% CI: 1.03 – 4.10) and gynecology cancer (OR: 6.79, 95% CI: 1.46 – 31.65). Additionally, a significant increase in breast cancer was observed with a family history of digestive system cancer for subjects 50 y and younger (OR: 1.88, 95% CI: 1.03 – 3.43), not for subjects 50 y older (OR: 1.67, 95% CI: 0.86 – 3.25).ConclusionsBreast cancer aggregates in families with several types of cancer especially for digestive system cancer. The influence of a family history of other cancers seems more likely to be limited to hormone receptor negative breast cancer.

Human mammary microenvironment better regulates the biology of human breast cancer in humanized mouse model.

During the past decades, many efforts have been made in mimicking the clinical progress of human cancer in mouse models. Previously, we developed a human breast tissue-derived (HB) mouse model. Theoretically, it may mimic the interactions between “species-specific” mammary microenvironment of human origin and human breast cancer cells. However, detailed evidences are absent. The present study (in vivo, cellular, and molecular experiments) was designed to explore the regulatory role of human mammary microenvironment in the progress of human breast cancer cells. Subcutaneous (SUB), mammary fat pad (MFP), and HB mouse models were developed for in vivo comparisons. Then, the orthotopic tumor masses from three different mouse models were collected for primary culture. Finally, the biology of primary cultured human breast cancer cells was compared by cellular and molecular experiments. Results of in vivo mouse models indicated that human breast cancer cells grew better in human mammary microenvironment. Cellular and molecular experiments confirmed that primary cultured human breast cancer cells from HB mouse model showed a better proliferative and anti-apoptotic biology than those from SUB to MFP mouse models. Meanwhile, primary cultured human breast cancer cells from HB mouse model also obtained the migratory and invasive biology for “species-specific” tissue metastasis to human tissues. Comprehensive analyses suggest that “species-specific” mammary microenvironment of human origin better regulates the biology of human breast cancer cells in our humanized mouse model of breast cancer, which is more consistent with the clinical progress of human breast cancer.