The management of early-stage and metastatic triple-negative breast cancer: a review

Evaluation of nipple aspirate fluid as a diagnostic tool for early detection of breast cancer

There has been tremendous progress in detection of breast cancer in postmenopausal women, resulting in two-thirds of women surviving more than 20 years after treatment. However, breast cancer remains the leading cause of cancer-related deaths in premenopausal women. Breast cancer is increasing in younger women due to changes in life-style as well as those at high risk as carriers of mutations in high-penetrance genes. Premenopausal women with breast cancer are more likely to be diagnosed with aggressive tumours and therefore have a lower survival rate. Mammography plays an important role in detecting breast cancer in postmenopausal women, but is considerably less sensitive in younger women. Imaging techniques, such as contrast-enhanced MRI improve sensitivity, but as with all imaging approaches, cannot differentiate between benign and malignant growths. Hence, current well-established detection methods are falling short of providing adequate safety, convenience, sensitivity and specificity for premenopausal women on a global level, necessitating the exploration of new methods. In order to detect and prevent the disease in high risk women as early as possible, methods that require more frequent monitoring need to be developed. The emergence of "omics" strategies over the last 20 years, enabling the characterisation and understanding of breast cancer at the molecular level, are providing the potential for long term, longitudinal monitoring of the disease. Tissue and serum biomarkers for breast cancer stratification, diagnosis and predictive outcome have emerged, but have not successfully translated into clinical screening for early detection of the disease. The use of breast-specific liquid biopsies, such as nipple aspirate fluid (NAF), a natural secretion produced by breast epithelial cells, can be collected non-invasively for biomarker profiling. As we move towards an age of active surveillance, home-based liquid biopsy collection kits are increasingly being applied and these could provide a paradigm shift where NAF biomarker profiling is used for routine breast health monitoring. The current status of established and newly emerging imaging techniques for early detection of breast cancer and the potential for alternative biomarker screening of liquid biopsies, particularly those applied to high-risk, premenopausal women, will be reviewed.

Colorectal cancer susceptibility loci as predictive markers of rectal cancer prognosis after surgery

To understand the molecular mechanism of rectal cancer and develop markers for disease prognostication, we generated and explored a dataset from 243 rectal cancer patients by gene expression microarray analysis of cancer samples and matched controls, and SNP-arrays of germline DNA. We found that two of the loci most strongly linked with colorectal cancer (CRC) risk, 8q24 (upstream of MYC) and 18q21 (in the intron of SMAD7), as well as 20q13 (in the intron of LAMA5), are tightly associated with the prognosis of rectal cancer patients. For SNPs on 18q21 (rs12953717 and rs4464148) and 20q13 (rs4925386), alleles that correlate with higher risk for the development of CRC are associated with shorter disease free survival (DFS). However, for rs6983267 on 8q24, the low risk allele is associated with a higher risk for recurrence and metastasis after surgery, and importantly, is strongly correlated with the resistance of CRC cell lines to chemoradiotherapy (CRT). We also found that although MYC expression is dramatically increased in cancer, patients with higher levels of MYC have a better prognosis. The expression of SMAD7 is weakly correlated with DFS. Notably, the presence of the 8q24 and 18q21 SNP alleles is not correlated with expression levels of MYC and SMAD7. rs4464148, and probably rs6983267 and rs4925386, are linked with overall survival time of patients. In conclusion, we show that several CRC risk SNPs detect subpopulations of rectal cancer patients with poor prognosis, and that rs6983267 probably affects prognosis through interfering with the resistance of cancer cells to CRT.

Treg depletion potentiates checkpoint inhibition in claudin-low breast cancer

Claudin-low breast cancer is an aggressive subtype that confers poor prognosis and is found largely within the clinical triple-negative group of breast cancer patients. Here, we have shown that intrinsic and immune cell gene signatures distinguish the claudin-low subtype clinically as well as in mouse models of other breast cancer subtypes. Despite adaptive immune cell infiltration in claudin-low tumors, treatment with immune checkpoint inhibitory antibodies against cytotoxic T lymphocyte-associated protein 4 (CTLA-4) and programmed death receptor 1 (PD-1) were ineffective in controlling tumor growth. CD4+FoxP3+ Tregs represented a large proportion of the tumor-infiltrating lymphocytes (TILs) in claudin-low tumors, and Tregs isolated from tumor-bearing mice were able to suppress effector T cell responses. Tregs in the tumor microenvironment highly expressed PD-1 and were recruited partly through tumor generation of the chemokine CXCL12. Antitumor efficacy required stringent Treg depletion combined with checkpoint inhibition; delays in tumor growth were not observed using therapies that modestly diminished the number of Tregs in the tumor microenvironment. This study provides evidence that the recruitment of Tregs to the tumor microenvironment inhibits an effective antitumor immune response and highlights early Treg recruitment as a possible mechanism for the lack of response to immune checkpoint blockade antibodies in specific subtypes of cancer that are heavily infiltrated with adaptive immune cells.

Triple-negative breast cancer in the elderly: Prognosis and treatment

Our objective is to characterize treatment of triple-negative breast cancer (TNBC) in older patients and measure mortality risk relative to younger women. We conducted a retrospective cohort study analysis of patients presenting with primary TNBC, age 25-93, stage I-III from 1990 to 2014, identified and tracked by our registry (n=771). Clinical characteristics were chart abstracted at diagnosis and follow-up. The Kaplan-Meier method was used to measure disease-specific survival (DSS) by age with Cox regression modeling for relative contribution of patient and clinical characteristics. Of patients, 80% were <65 years (n=612), 13% were 65-74 years (n=100), and 7% were 75 and older (n=59). Older women presented more often with lower stage BC (stage I: 31% age <65, 48% age 65-74, 39% age 75+; P=.014). All three age groups were equally likely to have radiation therapy (77%) but older patients were less often treated with adjuvant chemotherapy (<65=95%, 65-74=76%, 75+=39%; P<.001). Mean follow-up was 7.34 years and did not differ by age. Five-year DSS was equivalent across the three age groups (<65=85%, 65-74=90%, 75+=83%, P=.322). In Cox regression analysis controlling for stage, histologic and nuclear grade, diagnosis year, radiation and chemotherapy treatment, age was not significantly associated with disease-specific mortality. TNBC survival appears equivalent by age despite less aggressive treatment in patients 75 years and older. This may be a result of lower stage at diagnosis and decreased disease virulence resulting in comparative survival despite less treatment.

Significant Radiation Enhancement Effects by Gold Nanoparticles in Combination with Cisplatin in Triple Negative Breast Cancer Cells and Tumor Xenografts

Gold nanoparticles (AuNPs) and cisplatin have been explored in concomitant chemoradiotherapy, wherein they elicit their effects by distinct and overlapping mechanisms. Cisplatin is one of the most frequently utilized radiosensitizers in the clinical setting; however, the therapeutic window of cisplatin-aided chemoradiotherapy is limited by its toxicity. The goal of this study was to determine whether AuNPs contribute to improving the treatment response when combined with fractionated cisplatin-based chemoradiation in both in vitro and in vivo models of triple-negative breast cancer (MDA-MB-231^Luc+). Cellular-targeting AuNPs with receptor-mediated endocytosis (AuNP-RME) in vitro at a noncytotoxic concentration (0.5 mg/ml) or cisplatin at IC₂₅ (12 μM) demonstrated dose enhancement factors (DEFs) of 1.25 and 1.14, respectively; the combination of AuNP-RME and cisplatin resulted in a significant DEF of 1.39 in vitro. Transmission electron microscopy (TEM) images showed effective cellular uptake of AuNPs at tumor sites 24 h after intratumoral infusion. Computed tomography (CT) images demonstrated that the intratumoral levels of gold remained stable up to 120 h after infusion. AuNPs (0.5 mg gold per tumor) demonstrated a radiation enhancement effect that was equivalent to three doses of cisplatin at IC₂₅ (4 mg/kg), but did not induce intrinsic toxicity or increased radiotoxicity. Results from this study suggest that AuNPs are the true radiosensitizer in these settings. Importantly, AuNPs enhance the treatment response when combined with cisplatin-based fractionated chemoradiation. This combination of AuNPs and cisplatin provides a promising approach to improving the therapeutic ratio of fractionated radiotherapy.

Intrinsic cellular signaling mechanisms determine the sensitivity of cancer cells to virus-induced apoptosis

Cancer cells of epithelial and mesenchymal phenotypes exhibit different sensitivities to apoptosis stimuli, but the mechanisms underlying this phenomenon remain partly understood. We constructed a novel recombinant adenovirus expressing Ad12 E1A (Ad-E1A12) that can strongly induce apoptosis. Ad-E1A12 infection of epithelial cancer cells displayed dramatic detachment and apoptosis, whereas cancer cells of mesenchymal phenotypes with metastatic propensity were markedly more resistant to this virus. Notably, forced detachment of epithelial cells did not further sensitize them to Ad-E1A12-induced apoptosis, suggesting that cell detachment is a consequence rather than the cause of Ad-E1A12-induced apoptosis. Ad-E1A12 increased phosphorylation of AKT1 and ribosomal protein S6 through independent mechanisms in different cell types. Ad-E1A12–induced AKT1 phosphorylation was PI3K-dependent in epithelial cancer cells, and mTOR-dependent in mesenchymal cancer cells. Epithelial cancer cells upon Ad-E1A12-induced detachment could not sustain AKT activation due to AKT1 degradation, but AKT1 activation was maintained in mesenchymal cancer cells. Expression of epithelial cell-restricted miR-200 family in mesenchymal cells limited mTOR signaling and sensitized them to Ad-E1A12-induced cell killing. Thus, epithelial cancer cells rely on the canonical PI3K-AKT signaling pathway for survival, while mesenchymal cancer cells deploy the PI3K-independent mTORC2-AKT axis in response to strong death stimuli.

MENA Confers Resistance to Paclitaxel in Triple-Negative Breast Cancer

Taxane therapy remains the standard of care for triple-negative breast cancer. However, high frequencies of recurrence and progression in treated patients indicate that metastatic breast cancer cells can acquire resistance to this drug. The actin regulatory protein MENA and particularly its invasive isoform, MENA^INV, are established drivers of metastasis. MENA^INV expression is significantly correlated with metastasis and poor outcome in human patients with breast cancer. We investigated whether MENA isoforms might play a role in driving resistance to chemotherapeutics. We find that both MENA and MENA^INV confer resistance to the taxane paclitaxel, but not to the widely used DNA-damaging agents doxorubicin or cisplatin. Furthermore, paclitaxel treatment does not attenuate growth of MENA^INV-driven metastatic lesions. Mechanistically, MENA isoform expression alters the ratio of dynamic and stable microtubule populations in paclitaxel-treated cells. MENA expression also increases MAPK signaling in response to paclitaxel treatment. Decreasing ERK phosphorylation by co-treatment with MEK inhibitor restored paclitaxel sensitivity by driving microtubule stabilization in MENA isoform-expressing cells. Our results reveal a novel mechanism of taxane resistance in highly metastatic breast cancer cells and identify a combination therapy to overcome such resistance. Mol Cancer Ther; 16(1); 143-55. ©2016 AACR.

Mutant p53: a novel target for the treatment of patients with triple-negative breast cancer?

The identification and validation of a targeted therapy for patients with triple-negative breast cancer (TNBC) is currently one of the most urgent needs in breast cancer therapeutics. One of the key reasons for the failure to develop a new therapy for this subgroup of breast cancer patients has been the difficulty in identifying a highly prevalent, targetable molecular alteration in these tumors. Recently however, the p53 gene was found to be mutated in approximately 80% of basal/TNBC, raising the possibility that targeting the mutant p53 protein product might be a new approach for the treatment of this form of breast cancer. In this study, we investigated the anti-cancer activity of PRIMA-1 and PRIMA-1^MET (APR-246), two compounds which were previously reported to reactivate mutant p53 and convert it to a form with wild-type (WT) properties. Using a panel of 18 breast cancer cell lines and 2 immortalized breast cell lines, inhibition of proliferation by PRIMA-1 and PRIMA-1^MET was found to be cell-line dependent, but independent of cell line molecular subtype. Although response was independent of molecular subtype, p53 mutated cell lines were significantly more sensitive to PRIMA-1^MET than p53 WT cells (p = 0.029). Furthermore, response (measured as IC₅₀ value) correlated significantly with p53 protein level as measured by ELISA (p = 0.0089, r=-0.57, n = 19). In addition to inhibiting cell proliferation, PRIMA-1^MET induced apoptosis and inhibited migration in a p53 mutant-dependent manner. Based on our data, we conclude that targeting mutant p53 with PRIMA-1^MET is a potential new approach for treating p53-mutated breast cancer, including the subgroup with triple-negative (TN) disease.

Identification of a new class of natural product MDM2 inhibitor: In vitro and in vivo anti-breast cancer activities and target validation

The MDM2 oncogene has been suggested as a molecular target for treating human cancers, including breast cancer. Most MDM2 inhibitors under development are targeting the MDM2-p53 binding, and have little or no effects on cancers without functional p53, such as advanced breast cancer. The present study was designed to develop a new class of MDM2 inhibitors that exhibit anticancer activity in MDM2-dependent and p53-independent manners. The selective MDM2 inhibitors were discovered by a computational structure-based screening, yielding a lead compound, termed JapA. We further found that JapA inhibited cell growth, decreased cell proliferation, and induced G2/M phase arrest and apoptosis in breast cancer cells through an MDM2-dependent mechanism, regardless of p53 status. It also inhibited the tumor growth and lung metastasis in breast cancer xenograft models without causing any host toxicity. Furthermore, JapA directly bound to MDM2 protein and reduced MDM2 levels in cancer cells in vitro and in vivo by promoting MDM2 protein degradation and inhibiting MDM2 transcription, which is distinct from the existing MDM2 inhibitors. In conclusion, JapA represents a new class of MDM2 inhibitor that exerts its anticancer activity through directly down-regulating MDM2, and might be developed as a novel cancer therapeutic agent.

Radiation Nanomedicine for EGFR-Positive Breast Cancer: Panitumumab-Modified Gold Nanoparticles Complexed to the β-Particle-Emitter, (177)Lu

Our objective was to construct a novel radiation nanomedicine for treatment of breast cancer (BC) expressing epidermal growth factor receptors (EGFR), particularly triple-negative tumors (TNBC). Gold nanoparticles (AuNP; 30 nm) were modified with polyethylene glycol (PEG) chains (4 kDa) derivatized with 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) chelators for complexing the β-emitter, (177)Lu and with PEG chains (5 kDa) linked to panitumumab for targeting BC cells expressing EGFR. The AuNP were further coated with PEG chains (2 kDa) to stabilize the particles to aggregation. The binding and internalization of EGFR-targeted AuNP ((177)Lu-T-AuNP) into BC cells was studied and compared to nontargeted (177)Lu-NT-AuNP. The cytotoxicity of (177)Lu-T-AuNP and (177)Lu-NT-AuNP was measured in clonogenic assays using BC cells with widely different EGFR densities: MDA-MB-468 (10(6) receptors/cell), MDA-MB-231 (10(5) receptors/cell), and MCF-7 cells (10(4) receptors/cell). Radiation absorbed doses to the cell nucleus of MDA-MB-468 cells were estimated based on subcellular distribution. Darkfield and fluorescence microscopy as well as radioligand binding assays revealed that (177)Lu-T-AuNP were specifically bound by BC cells dependent on their EGFR density whereas the binding and internalization of (177)Lu-NT-AuNP was significantly lower. The affinity of binding of (177)Lu-T-AuNP to MDA-MB-468 cells was reduced by 2-fold compared to (123)I-labeled panitumumab (KD = 1.3 ± 0.2 nM vs 0.7 ± 0.4 nM, respectively). The cytotoxicity of (177)Lu-T-AuNP was dependent on the amount of radioactivity incubated with BC cells, their EGFR density and the radiosensitivity of the cells. The clonogenic survival (CS) of MDA-MB-468 cells overexpressing EGFR was reduced to <0.001% at the highest amount of (177)Lu-T-AuNP tested (4.5 MBq; 6 × 10(11) AuNP per 2.5 × 10(4)-1.2 × 10(5) cells). (177)Lu-T-AuNP were less effective for killing MDA-MB-231 cells or MCF-7 cells with moderate or low EGFR density (CS = 33.8 ± 1.6% and 25.8 ± 1.2%, respectively). Because the β-particles emitted by (177)Lu have a 2 mm range, (177)Lu-NT-AuNP were also cytotoxic to BC cells due to a cross-fire effect but (177)Lu-T-AuNP were significantly more potent for killing MDA-MB-468 cells overexpressing EGFR than (177)Lu-NT-AuNP at all amounts tested. The cross-fire effect of the β-particles emitted by (177)Lu may be valuable for eradicating BC cells in tumors that have low or moderate EGFR expression or cells that are not targeted by (177)Lu-T-AuNP as a consequence of heterogeneous intratumoral distribution. The radiation dose to the nucleus of a single MDA-MB-468 cell was 73.2 ± 6.7 Gy, whereas (177)Lu-NT-AuNP delivered 5.6 ± 0.6 Gy. We conclude that (177)Lu-T-AuNP is a promising novel radiation nanomedicine with potential application for treatment of TNBC, in which EGFR are often overexpressed.

Breast cancer under age 40: a different approach

Breast cancer (BC) under age 40 is a complex disease to manage due to the additionally fertility-related factors to be taken in consideration. More than 90% of young patients with BC are symptomatic. Women<40 years are more likely to develop BC with worse clinicopathological features and more aggressive subtype. This has been frequently associated with inferior outcomes. Recently, the prognostic significance of age<40 has been shown to differ according to the BC subtype, being associated with worst recurrence-free survival (RFS) and overall survival (OS) for luminal BC. The biology of BC<40 has also been explored through analysis of large genomic data set, and specific pathways overexpressed in these tumors have been identified which can lead to the development of targeted therapy in the future. A multidisciplinary tumor board should determine the optimal locoregional and systemic management strategies for every individual patient with BC before the start of any therapy including surgery. This applies to both early (early breast cancer (EBC)) and advanced (advanced breast cancer (ABC)) disease, before the start of any therapy. Mastectomy even in young patients confers no overall survival advantage when compared to breast-conserving treatment (BCT), followed by radiotherapy. Regarding axillary approach, indications are identical to other age groups. Young age is one of the most important risk factors for local recurrence after both breast-conserving surgery (BCS) and mastectomy, associated with a higher risk of distant metastasis and death. Radiation after BCS reduces local recurrence from 19.5 to 10.2% in BC patients 40 years and younger. The indications for and the choice of systemic treatment for invasive BC (both early and advanced disease) should not be based on age alone but driven by the biological characteristics of the individual tumor (including hormone receptor status, human epidermal growth factor receptor 2 (HER-2) status, grade, and proliferative activity), disease stage, and patient's comorbidities. Recommendations regarding the use of genomic profiles such as MammaPrint, Oncotype Dx, and Genomic grade index in young women are similar to the general BC population. Especially in the metastatic setting, patient preferences should always be taken into account, as the disease is incurable. The best strategy for these patients is the inclusion into well-designed, independent, prospective randomized clinical trials. Metastatic disease should always be biopsied whenever feasible for histological confirmation and reassessment of biology. Endocrine therapy is the preferred option for hormone receptor-positive disease (HR+ve), even in presence of visceral metastases, unless there is concern or proof of endocrine resistance or there is a need for rapid disease response and/or symptom control. Recommendations for chemotherapy (CT) should not differ from those for older patients with the same characteristics of the metastatic disease and its extent. Young age by itself should not be an indication to prescribe more intensive and combination CT regimens over the sequential use of monotherapy. Poly(ADP-ribose) polymerase inhibitors (PARP inhibitors) represent an important group of promising drugs in managing patients with breast cancer susceptibility gene (BRCA)-1- or BRCA-2-associated BC. Specific age-related side effects of systemic treatment (e.g., menopausal symptoms, change in body image, bone morbidity, cognitive function impairment, fertility damage, sexual dysfunction) and the social impact of diagnosis and treatment (job discrimination, taking care for children) should also be carefully addressed when planning systemic long-lasting therapy, such as endocrine therapy. Survivorship concerns for young women are different compared to older women, including issues of fertility, preservation, and pregnancy.

Vitamin C effect on mitoxantrone-induced cytotoxicity in human breast cancer cell lines

In recent years the use of natural dietary antioxidants to minimize the cytotoxicity and the damage induced in normal tissues by antitumor agents is gaining consideration. In literature, it is reported that vitamin C exhibits some degree of antineoplastic activity whereas Mitoxantrone (MTZ) is a synthetic anti-cancer drug with significant clinical effectiveness in the treatment of human malignancies but with severe side effects. Therefore, we have investigated the effect of vitamin C alone or combined with MTZ on MDA-MB231 and MCF7 human breast cancer cell lines to analyze their dose-effect on the tumor cellular growth, cellular death, cell cycle and cell signaling. Our results have evidenced that there is a dose-dependence on the inhibition of the breast carcinoma cell lines, MCF7 and MDA-MB231, treated with vitamin C and MTZ. Moreover, their combination induces: i) a cytotoxic effect by apoptotic death, ii) a mild G2/M elongation and iii) H2AX and mild PI3K activation. Hence, the formulation of vitamin C with MTZ induces a higher cytotoxicity level on tumor cells compared to a disjointed treatment. We have also found that the vitamin C enhances the MTZ effect allowing the utilization of lower chemotherapic concentrations in comparison to the single treatments.

Preferential, enhanced breast cancer cell migration on biomimetic electrospun nanofiber 'cell highways'

BACKGROUND

Aggressive metastatic breast cancer cells seemingly evade surgical resection and current therapies, leading to colonization in distant organs and tissues and poor patient prognosis. Therefore, high-throughput in vitro tools allowing rapid, accurate, and novel anti-metastatic drug screening are grossly overdue. Conversely, aligned nanofiber constitutes a prominent component of the late-stage breast tumor margin extracellular matrix. This parallel suggests that the use of a synthetic ECM in the form of a nanoscale model could provide a convenient means of testing the migration potentials of cancer cells to achieve a long-term goal of providing clinicians an in vitro platform technology to test the efficacy of novel experimental anti-metastatic compounds.

METHODS

Electrospinning produces highly aligned, cell-adhesive nanofiber matrices by applying a strong electric field to a polymer-containing solution. The resulting fibrous microstructure and morphology closely resembles in vivo tumor microenvironments suggesting their use in analysis of migratory potentials of metastatic cancer cells. Additionally, a novel interface with a gel-based delivery system creates CXCL12 chemotactic gradients to enhance CXCR4-expressing cell migration.

RESULTS

Cellular dispersions of MCF-10A normal mammary epithelial cells or human breast cancer cells (MCF-7 and MDA-MB-231) seeded on randomly-oriented nanofiber exhibited no significant differences in total or net distance traveled as a result of the underlying topography. Cells traveled ~2-5 fold greater distances on aligned fiber. Highly-sensitive MDA-MB-231 cells displayed an 82% increase in net distance traversed in the presence of a CXCL12 gradient. In contrast, MCF-7 cells exhibited only 31% increase and MCF-10A cells showed no statistical difference versus control or vehicle conditions. MCF-10A cells displayed little sensitivity to CXCL12 gradients, while MCF-7 cells displayed early sensitivity when CXCL12 concentrations were higher. MDA-MB-231 cells displayed low relative expression levels of CXCR4, but high sensitivity resulting in 55-fold increase at late time points due to CXCL12 gradient dissipation.

CONCLUSIONS

This model could create clinical impact as an in vitro diagnostic tool for rapid assessment of tumor needle biopsies to confirm metastatic tumors, their invasiveness, and allow high-throughput drug screening providing rapid development of personalized therapies.

Development of a robust RNA-based classifier to accurately determine ER, PR, and HER2 status in breast cancer clinical samples

Breast cancers are categorized into three subtypes based on protein expression of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER2/ERBB2). Patients enroll onto experimental clinical trials based on ER, PR, and HER2 status and, as receptor status is prognostic and defines treatment regimens, central receptor confirmation is critical for interpreting results from these trials. Patients enrolling onto experimental clinical trials in the metastatic setting often have limited available archival tissue that might better be used for comprehensive molecular profiling rather than slide-intensive reconfirmation of receptor status. We developed a Random Forests-based algorithm using a training set of 158 samples with centrally confirmed IHC status, and subsequently validated this algorithm on multiple test sets with known, locally determined IHC status. We observed a strong correlation between target mRNA expression and IHC assays for HER2 and ER, achieving an overall accuracy of 97 and 96 %, respectively. For determining PR status, which had the highest discordance between central and local IHC, incorporation of expression of co-regulated genes in a multivariate approach added predictive value, outperforming the single, target gene approach by a 10 % margin in overall accuracy. Our results suggest that multiplexed qRT-PCR profiling of ESR1, PGR, and ERBB2 mRNA, along with several other subtype associated genes, can effectively confirm breast cancer subtype, thereby conserving tumor sections and enabling additional biomarker data to be obtained from patients enrolled onto experimental clinical trials.

CDK4/6 inhibition provides a potent adjunct to Her2-targeted therapies in preclinical breast cancer models

In spite of the efficacy of Her2-targeted therapies, recurrence and progression remain a challenge for treatment of Her2 positive breast cancer. CDK4/6 controls pathway downstream of Her2, Inhibition of these kinases could represent an important therapeutic approach to augment the effectiveness of standard therapies. In models of acquired resistance to Her2-targeted therapies, Cyclin D1 was inappropriately activated and CDK4/6 inhibition was effective at blocking proliferation by targeting this common pathway associated with resistance. These data were recapitulated in Her2 positive xenografts. Furthermore, in a series of 35 primary breast tumor explants, treatment with PD-0332991 resulted in a greater than 4-fold suppression of the Ki67. The effects of CDK4/6 inhibition were dependent on an intact RB-pathway, and consonantly, loss of RB and high-levels of p16 were associated with resistance to CDK4/6 inhibition. Combination studies illustrated that CDK4/6 inhibition is cooperative with multiple Her2-targeted agents and provides a complementary mechanism of action to T-DM1 to efficiently suppresses the proliferation of residual Her2-positive tumor cell populations that survive T-DM1. Together, these data indicate CDK4/6 is a viable therapeutic target that functions downstream of Her2, and tissue based markers are available to direct rational utilization of CDK4/6 inhibitors in combination with Her2-targeted agents.

Disease and treatment characteristics do not predict symptom occurrence profiles in oncology outpatients receiving chemotherapy

BACKGROUND

A large amount of interindividual variability exists in the occurrence of symptoms in patients receiving chemotherapy (CTX). The purposes of the current study, which was performed in a sample of 582 oncology outpatients who were receiving CTX, were to identify subgroups of patients based on their distinct experiences with 25 commonly occurring symptoms and to identify demographic and clinical characteristics associated with subgroup membership. In addition, differences in quality of life outcomes were evaluated.

METHODS

Oncology outpatients with breast, gastrointestinal, gynecological, or lung cancer completed the Memorial Symptom Assessment Scale before their next cycle of CTX. Latent class analysis was used to identify subgroups of patients with distinct symptom experiences.

RESULTS

Three distinct subgroups of patients were identified (ie, 36.1% in Low class; 50.0% in Moderate class, and 13.9% in All High class). Patients in the All High class were significantly younger and more likely to be female and nonwhite, and had lower levels of social support, lower socioeconomic status, poorer functional status, and a higher level of comorbidity.

CONCLUSIONS

Findings from the current study support the clinical observation that some oncology patients experience a differentially higher symptom burden during CTX. These high-risk patients experience significant decrements in quality of life.

The anti-proliferative effect of metformin in triple-negative MDA-MB-231 breast cancer cells is highly dependent on glucose concentration: implications for cancer therapy and prevention

BACKGROUND

Metformin has been shown to have a strong anti-proliferative effect in many breast cancer cell lines, mainly due to the activation of the energy sensing kinase, AMP-activated protein kinase (AMPK). MDA-MB-231 cells are aggressive and invasive breast cancer cells that are known to be resistant to several anti-cancer agents as well as to the anti-proliferative effect of metformin. As metformin is a glucose lowering drug, we hypothesized that normoglycemia will sensitize MDA-MB-231 cells to the anti-proliferative effect of metformin.

METHODS

MDA-MB-231 cells were treated with increasing metformin concentrations in hyperglycemic or normoglycemic conditions. The growth inhibitory effect of metformin was assessed by MTT assay. The expression of several proteins involved in cell proliferation was measured by Western blotting.

RESULTS

In agreement with previous studies, treatment with metformin did not inhibit the growth of MDA-MB-231 cells cultured in hyperglycemic conditions. However, metformin significantly inhibited MDA-MB-231 growth when the cells were cultured in normoglycemic conditions. In addition, we show that metformin-treatment of MDA-MB-231 cells cultured in normoglycemic conditions and not in hyperglycemic conditions caused a striking activation of AMPK, and an AMPK-dependent inhibition of multiple molecular signaling pathways known to control protein synthesis and cell proliferation.

CONCLUSION

Our data show that normoglycemia sensitizes the triple negative MDA-MB-231 breast cancer cells to the anti-proliferative effect of metformin through an AMPK-dependent mechanism.

GENERAL SIGNIFICANCE

These findings suggest that tight normoglycemic control may enhance the anti-proliferative effect of metformin in diabetic cancer patients.