Favorable response to doxorubicin combination chemotherapy does not yield good clinical outcome in patients with metastatic breast cancer with triple-negative phenotype

In vitro to Clinical Translation of Combinatorial Effects of Doxorubicin and Abemaciclib in Rb-Positive Triple Negative Breast Cancer: A Systems-Based Pharmacokinetic/Pharmacodynamic Modeling Approach

Background

Doxorubicin (DOX) and its pegylated liposomal formulation (L_DOX) are the standard of care for triple-negative breast cancer (TNBC). However, resistance to DOX often occurs, motivating the search for alternative treatment approaches. The retinoblastoma protein (Rb) is a potential pharmacological target for TNBC treatment since its expression has been associated with resistance to DOX-based therapy.

Methods

DOX (0.01–20 μM) combination with abemaciclib (ABE, 1–6 μM) was evaluated over 72 hours on Rb-positive (MDA-MB-231) and Rb-negative (MDA-MB-468) TNBC cells. Combination indices (CI) for DOX+ABE were calculated using Compusyn software. The TNBC cell viability time-course and fold-change from the control of phosphorylated-Rb (pRb) protein expression were measured with CCK8-kit and enzyme-linked immunosorbent assay. A cell-based pharmacodynamic (PD) model was developed, where pRb protein dynamics drove cell viability response. Clinical pharmacokinetic (PK) models for DOX, L_DOX, and ABE were developed using data extracted from the literature. After scaling cancer cell growth to clinical TNBC tumor growth, the time-to-tumor progression (TTP) was predicted for human dosing regimens of DOX, ABE, and DOX+ABE.

Results

DOX and ABE combinations were synergistic (CI<1) in MDA-MB-231 and antagonistic (CI>1) in MDA-MB-468. The maximum inhibitory effects (Imax) for both drugs were set to one. The drug concentrations producing 50% of Imax for DOX and ABE were 0.565 and 2.31 μM (MDA-MB-231) and 0.121 and 1.61 μM (MDA-MB-468). The first-orders rate constants of abemaciclib absorption (k_a) and doxorubicin release from L_DOX (k_Rel) were estimated at 0.31 and 0.013 h⁻¹. Their linear clearances were 21.7 (ABE) and 32.1 L/h (DOX). The estimated TTP for intravenous DOX (75 mg/m2 every 21 days), intravenous L_DOX (50 mg/m² every 28 days), and oral ABE (200 mg twice a day) were 125, 31.2, and 8.6 days shorter than drug-free control. The TTP for DOX+ABE and L_DOX+ABE were 312 days and 47.5 days shorter than control, both larger than single-agent DOX, suggesting improved activity with the DOX+ABE combination.

Conclusion

The developed translational systems-based PK/PD model provides an in vitro-to-clinic modeling platform for DOX+ABE in TNBC. Although model-based simulations suggest improved outcomes with combination over monotherapy, tumor relapse was not prevented with the combination. Hence, DOX+ABE may not be an effective treatment combination for TNBC.

Antitumor properties of Salvianolic acid B against triple-negative and hormone receptor-positive breast cancer cells via ceramide-mediated apoptosis

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer with limited treatment options. It is urgent to develop new therapeutics against this disease. Salvinolic acid B (Sal-B) is a leading bioactive component of Salvia miltiorrhiza Bunge, a well-known Chinese medicine for treating various diseases without appreciable adverse effects. To understand the antitumor properties of Sal-B against TNBC, we analyzed its effects on the cell viability, cell cycle and apoptosis of triple-negative MDA-MB-231 cells with the hormone receptor-positive MCF-7 cells as the control. The in vitro analysis showed that Sal-B could significantly reduce the cell viability and suppress the proliferation of both MDA-MB-231 and MCF-7 cells with decreased cyclin B1 expression, but with no noticeable cell cycle phase change. In mouse models, Sal-B markedly inhibited the growth, decreased the PCNA expression, and increased the cell apoptosis of MDA-MB-231 tumor xenografts. To understand the antitumor mechanisms, we analyzed the expression levels of ceramides, and anti-apoptotic (Bcl-xL and survivin) and pro-apoptotic (caspase-3 and caspase-8) proteins. We found that Sal-B enhanced the ceramide accumulation and inhibited the anti-apoptotic protein expression. Interestingly, the ceramide accumulation was accompanied by decreased expression of glucosylceramide and GM3 synthases, two key enzymes regulating ceramide metabolism. These findings indicate that Sal-B exerts its antitumor effects at least partially by inducing the ceramide accumulation and ceramide-mediated apoptosis via inhibiting the expression of glucosylceramide and GM3 synthases, which was independent of estrogen receptor α. Sal-B appears to be a promising therapeutic agent against TNBC.

The relationship between nuclear factor (NF)-κB family gene expression and prognosis in triple-negative breast cancer (TNBC) patients receiving adjuvant doxorubicin treatment

We investigated gene expression profiles of the NF-κB pathway in patients with triple-negative breast cancer (TNBC) receiving adjuvant chemotherapy to determine the prognostic value of NF-κB pathway genes according to chemotherapeutic regimen. We used the nCounter expression assay to measure expression of 11 genes (NFKB1, NFKB2, RELA, RELB, REL, TP53, FOXC1, TBP, SP1, STAT3 and IRF1 genes) belonging to the NF-κB pathway using mRNA extracted from paraffin-embedded tumor tissues from 203 patients diagnosed with TNBC. Of the 203 patients, 116 were treated with a chemotherapeutic regimen containing doxorubicin. As revealed by the expression profiles of the 11 genes, increased expression of SP1 was associated with poor prognosis in TNBC patients treated with adjuvant doxorubicin chemotherapy (5-year distant recurrence-free survival [5Y DRFS], low vs. high expression [cut-off: median]: 92.3% vs. 71.6%, P = 0.001). In a multivariate Cox regression model, SP1 expression was a useful marker for predicting long-term prognosis in TNBC patients receiving doxorubicin treatment, and we thus suggest that SP1 expression could serve as a prognostic marker in these patients.

MicroRNA Profile in Response to Doxorubicin Treatment in Breast Cancer

Chemotherapy treatment is the standard in triple negative breast cancers, a cancer subgroup which lacks a specific target. The mechanisms leading to the response, as well as any markers that allow the differentiation between responder and non-responder groups prior to treatment are unknown. In parallel, miRNAs can act as oncogenes or tumor suppressors and there is evidence of their involvement in promoting resistance to anticancer drugs. Therefore we hypothesized that changes in miRNA expression after doxorubicin treatment may also be relevant in treatment response.

OBJECTIVE

To study miRNAs that are differentially expressed in response to doxorubicin treatment.

METHODS

One luminal-A and two triple negative, breast cancer cell lines were exposed to doxorubicin. Microarray analysis was performed to identify the common and differentially modified miRNAs. Genes and pathways that are theoretically regulated by these miRNAs were analyzed.

RESULTS

Thirteen miRNAs common to all three lines were modified, in addition to 25 that were specific to triple negative cell lines, and 69 that changed only in the luminal-A cell line. This altered expression pattern seemed to be more strongly related to the breast cancer subgroup than to the treatment. The analysis of target genes revealed that cancer related pathways were the most affected by these miRNAs, moreover many of them had been previously related to chemotherapy resistance; thus suggesting follow-up studies. Additionally, through functional assays, we showed that miR-548c-3p is implicated in doxorubicin-treated MCF-7 cell viability, suggesting a role for this miRNA in resistance.

The value of cytoplasmic Y-box-binding protein 1 as a prognostic marker for breast cancer in Korean

BACKGROUND

The human Y-box-binding protein 1 (YB-1) is a member of the DNA/RNA-binding family of proteins that regulates transcription and translation of genes. Previous studies suggest that YB-1 may have an oncogenic role in various cancers. In this study, we evaluate the prognostic value of cytoplasmic YB-1 with respect to breast cancer.

METHODS

Immunohistochemical staining study was performed with YB-1 using tissue block from 233 patients with invasive ductal carcinoma. Patients were divided into two groups according to expression of cytoplasmic YB-1 in tumor cell (high versus low). The relationship between the expression of YB-1, clinicopathological characteristics and breast cancer prognosis was analyzed.

RESULTS

Hormone receptor negativity, worse histologic and nuclear grade, high tumor stage, lymphovascular invasion and high Ki67 (≥14 %) were related with the increased expression of cytoplasmic YB-1 in tumor cell (p < 0.05). Although there was no significant difference in relapse-free survival (RFS) between the two groups (p = 0.412), difference in overall survival (OS) was statistically significant (p = 0.035). In multivariate analysis for OS, YB-1 was an independent prognostic factor (p = 0.043).

CONCLUSION

This suggests that the increased expression of cytoplasmic YB-1 in tumor cells can be regarded as an independent prognostic factor for breast cancer, related to poor prognostics. Expression of cytoplasmic YB-1 in cancer cell could be used as an independent prognostic marker for predicting OS in breast cancer.

Chemotherapy response assay test and prognosis for breast cancer patients who have undergone anthracycline- and taxane-based chemotherapy

PURPOSE

A chemotherapy response assay test is performed to evaluate the degree of tumor growth inhibition by a chemotherapeutic agent. Several studies have been done on its usefulness; however, to the best of our knowledge, only a few studies concerning the relationship between chemotherapy response assay test results and breast cancer patients' prognoses have been conducted. Thus, we performed this study to analyze this relationship.

METHODS

Among breast cancer patients who underwent curative surgery and neoadjuvant or adjuvant chemotherapy between August 2004 and December 2009, 102 were enrolled in this study. Chemotherapeutic regimens for patients were doxorubicin plus taxane or doxorubicin plus cyclophosphamide followed by taxane. We divided these patients into two groups (sensitive group [n=19] and resistant group [n=83]) and analyzed the relationship between chemosensitivity results and patient prognosis.

RESULTS

The sensitive group was associated with poor disease-free survival (DFS) (p=0.003) and overall survival (OS) (p<0.001). No significant differences were observed in tumor histology (p=0.548), tumor size (p=0.479), number of metastatic lymph nodes (p=0.326), histologic grade (p=0.077), or nuclear grade (p=0.216) between the two groups. However, in respect to molecular subtype, the HER2-positive type and triple negative breast cancer were more frequently observed in the sensitive group (p=0.001). In a univariate and multivariate analysis for DFS, doxorubicin sensitivity was significantly associated with a poor prognosis (p<0.05).

CONCLUSION

Better chemosensitivity results are associated with a poor prognosis in breast cancer patients who have undergone anthracycline- and taxane-based chemotherapy, however, examination of additional cases and the use of a longer study period are needed.

Clinical efficacy of local targeted chemotherapy for triple-negative breast cancer

BACKGROUND

The aim of the study was to evaluate the clinical efficacy of superselective intra-arterial targeted neo-adjuvant chemotherapy in the treatment of estrogen receptor (ER)-negative, progesterone receptor (PR)-negative, and human epidermal growth factor receptor 2 (HER2)-negative (triple-negative) breast cancer. PATIENTS AND METHODS.: A total of 47 triple-negative breast cancer patients (29 at stage II, 13 at stage III and 5 at stage IV) were randomly assigned to two groups: targeted chemotherapy group (n=24) and control group (n=23). Patients in the targeted chemotherapy group received preoperative superselective intra-arterial chemotherapy with CEF regimen (C: cyclophosphamide [600 mg/m(2)]; E: epirubicin [90 mg/m(2)]; F: 5-fluorouracil [600 mg/m(2)]), and those in the control group received routine neoadjuvant chemotherapy with CEF. The duration of the treatment, changes in lesions and the prognosis were determined.

RESULTS

The average course of the treatment was 15 days in the targeted chemotherapy group which was significantly shorter than that in the control group (31 days) (P<0.01). The remission rate of lesions was 91.6% in the targeted chemotherapy group and 60.9% in the control group, respectively. Among these patients, 9 died within two years, including 2 (both at IV stage) in the targeted chemotherapy group and 7 (2 at stage II, 4 at stage III and 1 at stage IV) in the control group.

CONCLUSIONS

As an neoadjuvant therapy, the superselective intra-arterial chemotherapy is effective for triple-negative breast cancer, with advantages of the short treatment course and favourable remission rates as well as prognoses.