New developments in the treatment of metastatic breast cancer: from chemotherapy to biological therapy

Baicalin inhibits the TGF-β1/p-Smad3 pathway to suppress epithelial-mesenchymal transition-induced metastasis in breast cancer

TGF-β1 is an epithelial-mesenchymal transition (EMT)-inducing factor that is critical in tumor progression. However, whether the effect of TGF-β1 on breast cancer is through the EMT pathway remains to be determined, and drug development based on this mechanism needs to be improved. Results of this study showed that TGF-β1 dysregulation significantly correlated with the expression levels of EMT-associated markers and transcriptional factors. Exogenous expression of TGF-β1 promoted breast cancer cell metastasis and EMT progression. In addition, direct binding of baicalin to TGF-β1 caused its inactivation, which subsequently blocked signal transduction and inhibited breast cancer cell metastasis. In vivo experiment results further invalidated the inhibitory effect of baicalin on TGF-β1-induced tumor metastasis. These results suggest that baicalin, an active ingredient used in traditional Chinese medicine, exhibits a potential therapeutic effect on breast cancer metastasis by regulating TGF-β1-dependent EMT progression.

GSTT1, GSTP1, and GSTM1 genetic variants are associated with survival in previously untreated metastatic breast cancer

Purpose

The polymorphisms in genes including GSTM1, GSTP1 and GSTT1 have been found to predict development and therapeutic efficacy in various malignancies. Breast cancer is one of most common cancers among women. In this study, we evaluated the prognostic value of three functional polymorphisms of GSTs in patients with previously untreated metastatic breast cancer (MBC).

Patients and Methods

The genotype of GSTT1, GSTP1, and GSTM1 in 170 patients with previously untreated MBC from one single center were assessed via PCR-based RFLP methods. The prognostic of polymorphisms on overall survival (OS) was examined using the Kaplan-Meier estimates and Cox proportional hazard ratio (HR) regression analyses.

Results

The null genotypes of GSTT1 and GSTM1 were significantly correlated to poor OS compared with the present genotypes, respectively. After adjusting for clinic-pathologic factors, GSTT1 and GSTM1 genetic variants were still significantly associated with OS (HR, 1.92; 95% CI, 1.26-2.91 and HR, 1.53; 95% CI, 1.05-2.23). GSTT1 and GSTM1 were independent survival predictors and GSTP1 was not associated with overall survival of previous untreated MBC.

Conclusion

This exploratory analysis suggests that in addition to clinic-pathologic factors, the genetic variants in GSTT1 and GSTM1 might be predictive of survival outcome in patients with previously untreated MBC.

Efficacy and Safety of Nedaplatin in Advanced Breast Cancer Therapy

PURPOSE

To compare the time-to-treatment failure (TTF), overall survival (OS), overall response rate (ORR), and adverse effects of regimens including nedaplatin- or cisplatin-based chemotherapy for advanced breast cancer (ABC).

METHODS

A total of 171 patients with ABC (admission between July 2008 and July 2013) were retrospectively analyzed. Patients received either nedaplatin 75 mg/m(2) (arm N; n = 85) or cisplatin 75 mg/m(2) (arm C; n = 86) in combination with other second-generation chemotherapeutic drugs, such as paclitaxel 175 mg/m(2), docetaxel 75 mg/m(2), gemcitabine 1.25 g/m(2), and navelbine 25 mg/m(2) every 21 days (nedaplatin, cisplatin, paclitaxel, docetaxel on day 1; gemcitabine, navelbine on days 1 and 8). The primary endpoint was TTF in each arm; secondary endpoints were OS, ORR, and toxicity.

RESULTS

In the assessable patient population, in arm N, median TTF and OS was 13.87 months (95% CI: 11.55-16.19) and 31.53 months (95% CI: 28.42-34.64), respectively, with an ORR of 48.2%. In arm C, median TTF and OS was 8.7 months (95% CI: 5.82-11.59) and 24.87 months (95% CI: 18.98-30.75), respectively, with an ORR of 37.2%. The occurrence of grades 3 and 4 hematologic toxicity was more frequent (45.9% vs. 25.6%, p = 0.003) in arm N than in arm C. However, grade ≥2 nonhematologic toxicity was less frequent in arm N than in arm C (12.9% vs. 46.5%, p = 2.05 × 10(-7)).

CONCLUSIONS

Nedaplatin-based chemotherapy regimen was well tolerated and efficiently improved patients' quality of life characterized by prolonged TTF and OS, with a marginal ORR.

The efficacy of bevacizumab plus paclitaxel as first-line treatment for HER2-negative metastatic breast cancer: a meta-analysis of randomized controlled trials

Although both bevacizumab and paclitaxel significantly improve the efficacy of chemotherapy for human epidermal growth factor receptor 2 (HER2)-negative patients with metastatic breast cancer (MBC), little have changed with overall survival rates when they have been used alone or combined with other chemotherapy. Thus, a meta-analysis was conducted to evaluate the efficacy of bevacizumab combined with paclitaxel in HER2-negative MBC patients. Pubmed and Embase were systematically reviewed for studies published up to September 2013 in which bevacizumab plus paclitaxel were compared with other chemotherapy. Primary outcomes comprised overall survival (OS), progression-free survival (PFS), and objective response rate (ORR). Eight phase II/III clinical trials met the inclusion criteria, with a total of 3,758 patients. The pooled results showed that combination of bevacizumab and paclitaxel significantly improved the PFS (HR = 0.63, 95% CI, 0.55-0.73, P = 0.011), ORR (RR = 1.28, 95% CI, 0.96-1.70, P = 0.0), but had no effect on OS (HR = 0.91, 95% CI, 0.81-1.01, P = 0.855). The meta-analysis confirms the benefits of bevacizumab-paclitaxel combination therapy in HER2 negative metastatic breast cancer, with an improvement in both progression free survival and objective response rate. However, no significant OS benefit was observed.

A novel anthracene derivative, MHY412, induces apoptosis in doxorubicin-resistant MCF-7/Adr human breast cancer cells through cell cycle arrest and downregulation of P-glycoprotein expression

New potential chemotherapeutic strategies are required to overcome multidrug resistance (MDR) in cancer. This study investigated the anticancer effect of a novel anthracene derivative MHY412 on doxorubicin-resistant human breast cancer (MCF-7/Adr) cells. We measured cell viability and the expression of apoptosis-related genes; in addition, the antitumor activity of MHY412 was confirmed using an in vivo tumor xenograft model. MHY412 significantly inhibited the proliferation of MCF-7/Adr and MCF-7 cells in a concentration-dependent manner. Notably, the half-maximal inhibitory concentration (IC50) values of MHY412 in MCF-7/Adr (0.15 µM) and MCF-7 (0.26 µM) cells were lower than those of doxorubicin (MCF-7/Adr, 13.6 µM and MCF-7, 1.26 µM) after treatment for 48 h. MHY412 at low concentrations induced S phase arrest, but at high concentrations, the number of MCF-7/Adr cells in the sub-G1 phase significantly increased. MHY412-induced sub-G1 phase arrest was associated with inhibition of cyclin, cyclin-dependent kinase 2 (CDK2) and p21 expression in MCF-7/Adr cells. MHY412 markedly reduced P-glycoprotein (P-gp) expression and increased apoptotic cell death in MCF-7/Adr cells. Cleavage of poly-ADP ribose polymerase, reduced Bcl-2 expression, and increased in cytochrome c release in MCF-7/Adr cells confirmed the above results. In addition, MHY412 markedly inhibited tumor growth in a tumor xenograft model of MCF-7/Adr cells. Our data suggest that MHY412 exerts antitumor effects by selectively modulating the genes related to cell cycle arrest and apoptosis. In particular, MHY412 is a new candidate agent for the treatment of Bcl-2 overexpressed doxorubicin-resistant human breast cancer.

The maximum standardized uptake value of 18 F-FDG PET scan to determine prognosis of hormone-receptor positive metastatic breast cancer

Background

Whether PET scan maximum standard uptake value (SUVmax) could differentiate luminal A from luminal B and help predict the survival of metastatic breast cancer (MBC) patients with luminal subtype is still unknown and need to be investigated.

Methods

305 MBC patients with luminal subtypes were screened with PET/CT. Eligible patients were prospectively followed up.

Results

In total, 134 patients were eligible for this study. SUVmax was significantly related to the number of metastatic sites and presence of visceral metastasis on univariate analysis. SUVmax could not effectively differentiate patients with luminal A from luminal B subtype. Although luminal subtype at diagnosis could predict the relapse-free interval, it could not predict progression-free survival (PFS) or overall survival (OS) after developing relapse. In contrast, SUVmax was predictive of both PFS and OS and this effect was maintained in multivariate COX regression model.

Conclusions

SUVmax of MBC did not correlate with molecular subtypes of primary tumor. While molecular subtype may be a valuable prognostic factor at primary diagnosis of breast cancer, the SUVmax, rather than molecular subtype, does have a potential to predict independently in multivariate analysis for the PFS and OS in patients with metastatic disease of luminal subtype.

Vinorelbine and capecitabine in anthracycline- and/or taxane-pretreated metastatic breast cancer: sequential or combinational?

PURPOSE

The difference between combinational and pre-planned sequential therapies using regimens that include non-anthracycline and taxane in the first-line setting remains unclear. The purpose of this study is to explore the interaction between vinorelbine (N) and capecitabine (X) in breast cancer cells and to compare the simultaneous or sequential administration of the two drugs in patients with metastatic breast cancer (MBC) as first-line treatment.

METHODS

First, we explored the effects of vinorelbine on thymidine phosphorylase (TP) and thymidylate synthase (TS) expression in breast cancer cells. Next, we designed a prospective randomized phase II trial of MBC patients comparing the combinational and pre-planned sequential administration of vinorelbine and capecitabine in the first-line metastatic setting. The primary end point was progression-free survival (PFS). The correlation between clinical characteristics and class III β-tubulin expression and patient survival was also explored.

RESULTS

Vinorelbine upregulates TP and downregulates TS in breast cancer cells, thereby further sensitizing tumor cells to capecitabine, which indicated the proper order for sequential therapy should be N → X. Sixty patients were eligible for the phase II trial. No significant difference was observed between the combinational arm and the sequential arm in terms of progression-free survival (PFS), overall response rate (ORR), and overall survival (OS). Only in the subgroup of patients with liver metastases were median PFS and OS significantly prolonged in the combinational arm (8.5 vs. 6.4 months, P = 0.041 and 23.8 vs. 13.9 months, P = 0.028, respectively). No association between class III β-tubulin expression and patient outcome was identified. Grade 3/4 adverse events were more common in the combinational arm.

CONCLUSIONS

Both the NX regimen and pre-planned sequential N → X regimen are acceptable as first-line treatments with comparable efficacies for MBC patients previously treated with anthracyclines and/or taxanes. Sequential monotherapies are recommended as the preferred approach to first-line chemotherapy for most MBC patients in the absence of an imminent visceral crisis and the need for rapid symptom and/or disease control.

Deoxyelephantopin impedes mammary adenocarcinoma cell motility by inhibiting calpain-mediated adhesion dynamics and inducing reactive oxygen species and aggresome formation

We previously showed that deoxyelephantopin (DET), a plant sesquiterpene lactone, exhibits more profound suppression than paclitaxel (PTX) of lung metastasis of mammary adenocarcinoma TS/A cells in mice. Proteomics studies suggest that DET affects actin cytoskeletal protein networks and downregulates calpain-mediated proteolysis of several actin-associated proteins, whereas PTX mainly interferes with microtubule proteins. Here, DET was observed to significantly deregulate adhesion formation in TS/A cells, probably through inhibition of m-calpain activity. Epithelial growth factor (EGF)-mediated activation of Rho GTPase Rac1 and formation of lamellipodia in TS/A cells were remarkably suppressed by DET treatment. Further, DET impaired vesicular trafficking of EGF and induced protein carbonylation and formation of centrosomal aggregates in TS/A cells. DET-induced reactive oxygen species were observed to be the upstream stimulus for the formation of centrosomal ubiquitinated protein aggregates that might subsequently restrict cancer cell motility. PTX, however, caused dramatic morphological changes, interfered with microtubule networking, and moderately inhibited calpain-mediated cytoskeletal and focal adhesion protein cleavage in TS/A cells. This study provides novel mechanistic insights into the pharmacological action of DET against metastatic mammary cell migration and suggests that modulation of oxidative stress might be a potential strategy for treatment of metastatic breast cancer.

Survival benefit of eribulin mesylate in heavily pretreated metastatic breast cancer: what next?

Eribulin is a synthetic analog of halichondrin B, a non-taxane microtubule inhibitor extracted from the marine sponge, Halichondria okaida. It presents a novel mechanism of action and is active on cancer cells resistant to other antimicrotubule agents. It was granted approval in the USA and Europe for the treatment of heavily pretreated metastatic breast cancer. Early trials had shown activity in this setting with main toxicities being neutropenia and neuropathy in patients where quality of life is essential. Approvals were granted after a phase 3 trial demonstrated overall survival benefit in metastatic breast cancer previously treated with anthracyclines, taxanes, and capecitabine, in a setting where most treatments are failing to demonstrate a survival benefit. Recent data suggest that this survival benefit is also consistent in the elderly with no excess toxicity. Future strategies of eribulin are being tested in ongoing trials, evaluating this drug in earlier metastatic lines as well as in the adjuvant and the neoadjuvant settings.

A phase II randomized study comparing navelbine and capecitabine (Navcap) followed either by Navcap or by weekly docetaxel in the first-line treatment of HER-2/neu negative metastatic breast cancer

Following the proven efficacy and tolerability of Navcap and Navcap followed by docetaxel in the treatment of MBC, a phase II randomized study was initiated to assess the ORR of both arms in the first-line setting of MBC. Patients with no prior chemotherapy for MBC and HER-2/neu negative were eligible. All patients received Navcap (V 25 mg/m2 on d1 and d8 and C 825 mg/m2 bid D1-14 q3w) for a total of 4 cycles. Patients progressing under Navcap were withdrawn and received docetaxel as second-line treatment. Patients responding or stable were randomized to 2 arms: 4 cycles of Navcap (A) or 12 weekly docetaxel (25 mg/m²/week) (B). From July 2004 to July 2008, a total of 106 patients were enrolled. Ninety-four patients were evaluable before randomization, with a clinical benefit of 58%. Twenty-one patients (22%) had disease progression and were therefore not randomized. Forty-one patients were randomized to arm A and 29 patients to arm B. ORRs were 56 and 71% in arms A and B, respectively. The median time to progression and overall survival were 10 and 35 months in arm A and 12 and 37 months in arm B. Adverse events were mild. Arm A: grade 3-4 neutropenia (10%), grade 3 anemia (5%). Arm B: grade 3 neutropenia (6%), grade 3 anemia (6.2%), and grade 2 alopecia (12%).

CONCLUSION

Both Navcap and Navcap followed by Docetaxel regimens were tolerated with manageable toxicity, offering consistent activities in terms of response rate for metastatic breast cancer patients.

A Phase II trial of the combination of vinorelbine and capecitabine as second-line treatment in metastatic breast cancer previously treated with taxanes and/or anthracyclines

PURPOSE

Survival time for metastatic breast cancer (MBC) can be substantially improved by combination chemotherapy in the adjuvant setting. Capecitabine and vinorelbine have shown considerable efficacy and favourable toxicity as single agents. The aim of this study is to evaluate the response to the combination of capecitabine and vinorelbine as second-line treatment in patients previously treated with taxanes and/or anthracyclines.

PATIENTS AND METHODS

Thirty-nine patients with MBC, who received a combination of vinorelbine and capecitabine were included in the study.

RESULTS

Overall response rate was 53.9% and disease progression rate was 28.2% for patients who received six cycles of therapy, rates significantly higher than the three-cycle group. The treatment was generally well tolerated and toxicity was mild.

CONCLUSIONS

The combination of capecitabine and vinorelbine as salvage therapy in anthracycline- and/or taxane-pre-treated patients with MBC seems to be effective and safe, even more so as the number of treatment cycles increases.

Sequential vinorelbine–capecitabine followed by docetaxel in advanced breast cancer: long-term results of a pilot phase II trial

PURPOSE

To evaluate the response rate of the combination of capecitabine (C) and vinorelbine (V) followed by Docetaxel (D) in the 1st line treatment of advanced and metastatic breast cancer patients.

PATIENTS AND METHODS

Patients with measurable disease and no prior chemotherapy in advanced disease were eligible. Pts received V 25 mg/m(2) on day 1 and 8 in combination with C 825 mg/m(2) twice a day from day 1 to 14 every 3 weeks for four cycles followed by 12 consecutive weeks of D 25 mg/m(2)/w.

RESULTS

Between March 2002 and November 2003, 40 patients were enrolled. Median age was 57 years. Of patients, 77.5% of pts had visceral involvement and 32.5% had more than two metastatic sites. In the adjuvant setting, 62.5% received anthracycline and 10% Taxanes. In the intent-to-treat population, an overall objective response was observed in 25 patients (62.5, 95% CI, 45.8-77.27) and stable disease in 5 (12.5%). Median time till progression (TTP) was 12.3 months (range 1.5-48; 95% CI, 10.05-14.54). The median survival was 35.7 months (range 2-47). Reported grade 3-4 toxicities under Navcap were neutropenia (4 pts), anemia (1 pt), thrombopenia (1 pt) and febrile neutropenia (3 pts). Reported grade 3-4 toxicities under weekly Docetaxel were neutropenia (1 pt), thrombopenia (2 pts), leucopenia (1 pt) and anemia (1 pt).

CONCLUSION

The sequential use of Navcap followed by weekly Docetaxel demonstrated an interesting efficacy with a prolonged TTP and OS and warrants further evaluation.

Breast cancer proteomics: clinical perspectives

Breast cancer is the one of leading causes of cancer-related deaths in women within economically developed regions of the world. A major focus of present research into this malignancy is the identification of new biomarkers and drug targets to improve detection and treatment. Proteomics represents one of the latest technological developments in this context. It aims to analyse the complex circuitry of the breast cancer proteome. Here, the authors review how breast cancer proteomics has progressed so far, with emphasis on its potential application to clinically relevant scenarios.

Polymorphisms in XRCC1, XRCC3, and CCND1 and Survival After Treatment for Metastatic Breast Cancer

Purpose

Single nucleotide polymorphisms (SNPs) in DNA repair and cell cycle control genes may alter protein function and therefore the efficacy of DNA damaging chemotherapy. We retrospectively evaluated the association of SNPs in DNA repair genes, XRCC1-01 (Arg399Gln) and XRCC3-01 (Thr241Met), and a cell cycle control gene, CCND1-02 (A870G), with progression-free survival (PFS) and breast cancer specific survival (BCSS) in patients with metastatic breast cancer (MBC).

Patients and Methods

SNPs in 95 patients with MBC enrolled onto one of five prospective clinical trials of high-dose chemotherapy and autologous stem-cell transplantation were evaluated using genotyping assays.

Results

For XRCC1-01, the hazard ratio (HR) for BCSS was 2.8 (95% CI, 1.60 to 5.00) and the HR for PFS was 2.0 (95%CI, 1.12 to 3.43). For XRCC3-01, the HR for BCSS was 2.0 (95%CI, 1.12 to 3.70) and the HR for PFS was 2.0 (95%CI, 1.09 to 3.59). For CCND1-02, the HR for BCSS was 1.8 (95%CI, 1.12 to 2.78) and the HR for PFS was 1.8 (95%CI, 1.15 to 2.85). Patients carrying one variant genotype (HR, 1.7; 95%CI, 1.07 to 2.82) or combinations of any two variant genotypes (HR, 4.7; 95% CI, 2.41 to 8.94) had significantly poorer BCSS compared with patients carrying zero variants. In multivariable analysis, XRCC1-01, presence of liver metastases, and bone metastases independently predicted BCSS. Combinations of any two variant genotypes were stronger independent predictors of BCSS and PFS than the presence of liver or bone metastases.

Conclusion

XRCC1-01, XRCC3-01, and CCND1-01 may be predictive of survival outcome in patients with MBC treated with DNA damaging chemotherapy.

HRPAP20: a novel calmodulin-binding protein that increases breast cancer cell invasion

We previously reported the identification of HRPAP20 (hormone-regulated proliferation-associated protein 20), a novel hormone-regulated, proliferation-associated protein. In tumor cell lines, constitutive HRPAP20 expression enhanced proliferation and suppressed apoptosis, characteristics frequently associated with malignant progression. Here, we report that highly invasive breast cancer cell lines and human breast tumor specimens express elevated HRPAP20, which in transfection experiments in MCF-7 and MDA-MB-231 cells, increased invasion. Results from mechanistic studies revealed that HRPAP20 bound to calmodulin (CaM) via a conserved CaM-binding motif. Transfection of MCF-7 breast cancer cells with HRPAP20 harboring a mutated CaM-binding motif (HRPAP20K73A) inhibited its interaction with CaM and failed to increase invasion. Other experiments revealed that transfection with HRPAP20, but not HRPAP20K73A, increased secretion of matrix metalloproteinase-9 (MMP-9). Moreover, knockdown of HRPAP20 with small interfering RNA in MCF-7/HRPAP20 transfectants and wild-type MDA-MB-231 cells reduced invasion and inhibited secretion of MMP-9. Together these observations suggest that HRPAP20 may be an important regulator of breast tumor cell invasion by a CaM-mediated mechanism that leads to increased MMP-9 secretion. We conclude that dysregulation of HRPAP20 expression in tumor cells may contribute to the observed phenotypic changes associated with breast cancer progression.

Serum tumor markers in breast cancer: are they of clinical value?

BACKGROUND

Although multiple serum-based tumor markers have been described for breast cancer, such as CA 15-3, BR 27.29 (CA27.29), carcinoembryonic antigen (CEA), tissue polypeptide antigen, tissue polypeptide specific antigen, and HER-2 (the extracellular domain), the most widely used are CA 15-3 and CEA.

METHODS

The literature relevant to serum tumor markers in breast cancer was reviewed. Particular attention was given to systematic reviews, prospective randomized trials, and guidelines issued by expert panels.

RESULTS

Because of a lack of sensitivity for early disease and lack of specificity, none of the available markers is of value for the detection of early breast cancer. High preoperative concentrations of CA 15-3 are, however, associated with adverse patient outcome. Although serial determinations of tumor markers after primary treatment for breast cancer can preclinically detect recurrent/metastatic disease with lead times of approximately 2-9 months, the clinical value of this lead time remains to be determined. Serum markers, however, are the only validated approach for monitoring treatment in patients with advanced disease that cannot be evaluated by use of conventional criteria.

CONCLUSIONS

CA 15-3 is one of the first circulating prognostic factors for breast cancer. Preoperative concentrations thus might be combined with existing prognostic factors for predicting outcome in patients with newly diagnosed breast cancer. At present, the most important clinical application of CA 15-3 is in monitoring therapy in patients with advanced breast cancer that is not assessable by existing clinical or radiologic procedures.