Current status of hormone therapy in patients with hormone receptor positive (HR+) advanced breast cancer

In vitro evaluation of dioscin and protodioscin against ER-positive and triple-negative breast cancer

Women's breast cancer is one of the most significant healthcare issues for the human race that demands a proactive strategy for a cure. In this study, the cytotoxic activity (MTT assay) of two natural steroidal compounds, protodioscin and dioscin, against two major subtypes of human breast cancer estrogen receptor-positive (ER-positive)/MCF-7 and triple-negative breast cancer (TNBC)/MDA-MB-468), was assessed. The clonogenic capacity was evaluated using the clonogenic assay. Oxidative stress was determined by measuring the formation of malondialdehyde and H2O2 and the assessment of total antioxidant enzyme activities (SOD, GPx, GR, and TrxR). Protodioscin and dioscin were highly cytotoxic against the tested cell lines (1.53 μM <IC50< 6 μM) with low cytotoxicity on normal cells (PBMC; IC50 ≥ 50 μM). Interestingly, these compounds were responsible for a substantial decrease in the clonogenic capacity of both cell lines. Moreover, dioscin was able to reduce the cell motility of the invasive breast cancer cells (MDA-MB-468). At the molecular level, the two treatments resulted in an increase of reactive oxygen species. Notably, both compounds were responsible for decreasing the enzymatic activities of glutathione reductase and thioredoxin reductase. On the basis of such considerations, protodioscin and dioscin may serve as promising natural compounds to treat TNBC and ER-positive breast cancer through the induction of oxidative stress.

Diagnostic and Prognostic Role of 18F-Fluoroestradiol PET in Metastatic Breast Cancer: The Second Youth of an Older Theranostic Concept

Since the discovery of the role of female hormones in breast cancer (BC) pathophysiology, in vivo detection of oestrogen receptor (ER) distribution has been one of the major goals of nuclear medicine and molecular imaging [...]

Discoidin Domain Receptor 2 Expression as Worse Prognostic Marker in Invasive Breast Cancer

Discoidin domain receptor 2 (DDR2) is arising as a promising therapeutic target in breast carcinoma (BC). The ability of DDR2 to bind to collagen promotes protumoral responses in cancer cells that influence the tumor microenvironment (TME). Nonetheless, the interrelation between DDR2 expression and TME modulation during BC progression remains poorly known. For this reason, we aim to evaluate the correlation between intratumoral expression of DDR2 and the infiltration of the main TME cell populations, cancer-associated fibroblasts (CAFs), and tumor-associated macrophages (TAMs). First, collagen and DDR2 expression levels were analyzed in human invasive BC samples. Then, DDR2 status correlation with tumor aggressiveness and patient survival were retrieved from different databases. Subsequently, the main pathways, cell types, and tissues correlated with DDR2 expression in BC were obtained through bioinformatics approach. Finally, we studied the association of DDR2 expression with the recruitment of CAFs and TAMs. Our findings showed that, together with the expected overexpression of TME markers, DDR2 was upregulated in tumor samples. Besides, we uncovered that altered TME markers were linked to DDR2 expression in invasive BC patients. Consequently, DDR2 modulates the stromal reaction through CAFs and TAMs infiltration and could be used as a potential worse prognostic factor in the treatment response of invasive BC.

Treatment patterns and outcomes following disease progression on anti-PD-1 therapies for advanced melanoma

Background: Anti-PD-1-based therapies prolong survival in advanced melanoma, but disease progression is common. This study evaluated treatment patterns and overall survival (OS) after anti-PD-1 progression. Methods: Retrospective data from patients with advanced melanoma and progression on anti-PD-1 treatment between 2014 and 2019 were taken from Flatiron Health, which reflects largely community practice. Treatment patterns and OS were analyzed for BRAF mutant (mt) and wild-type (wt) subgroups; OS was also examined across all patients. Results: Progression following anti-PD-1 was recorded for 679 patients. Median OS ranged from 5.0 to 11.3 months. Of 275 BRAFmt and 374 BRAFwt patients, 113 (41.1%) and 228 (61.0%) received no subsequent therapy, respectively. However, 48.4% of BRAFmt and 57.8% of BRAFwt patients continued anti-PD-1 treatment beyond progression. Conclusion: This real-world study underscores the need for effective treatments for advanced melanoma post-progression on anti-PD-1 therapy.

Highly Expressed Progesterone Receptor B Isoform Increases Platinum Sensitivity and Survival of Ovarian High-Grade Serous Carcinoma

Simple Summary

Ovarian high-grade serous carcinoma is the deadliest ovarian cancer. Cancer cells develop resistance to anti-cancer regimens leading to poor prognosis. Previous studies showed that the progesterone receptor was associated with better rates of survival of ovarian cancer patients. We aimed to investigate the association between the progesterone receptor and its isoform-B and platinum sensitivity of ovarian high-grade serous carcinoma. We found that strong progesterone receptor-B expression was associated with better platinum sensitivity and better survival in high-grade serous ovarian cancer patients. Our clinical data also showed that a high expression of progesterone receptor-B and optimal debulking were the independent factors associated with better platinum sensitivity. In a cell model, enhancing progesterone receptor-B expression and progesterone treatment increased platinum sensitivity and platinum-related apoptosis of the ovarian cancer cells. These might be potential therapeutic targets of ovarian high-grade serous carcinoma.

Abstract

Background: Expression of the progesterone receptor (PR) has been reported to influence survival outcomes in patients with ovarian high-grade serous carcinoma (HGSC). In the present study, we attempted to investigate the association among PR and its isoforms’ expression, platinum sensitivity, and survival in ovarian HGSC. Material and methods: This retrospective study reviewed ovarian HGSC patients who received surgery followed by adjuvant chemotherapy. We analyzed total PR and PR isoform-B (PR-B) expression by immunohistochemical staining and quantified using the H-score. Then, we compared platinum sensitivity and survival outcomes between those patients with weak and strong PR-B expression. Cisplatin viability assays were carried out in ovarian HGSC cell lines (OC-3-VGH and OVCAR-3) with different PR-B expression. Results: Among 90 patients, 49 and 41 patients were considered to have platinum-sensitive and platinum-resistant disease, respectively. Pearson’s correlation model showed that the H-score of total PR correlated positively with PR-B (r = 0.813). The PR-B H-score of tumors was significantly higher in the platinum-sensitive group (p = 0.004). Multivariate analysis revealed that the PR-B H-score and optimal debulking status were independent factors predicting platinum sensitivity. When compared with strong PR-B expression, patients with weak PR-B had significantly poorer progression-free (p = 0.021) and cancer-specific survival (p = 0.046). In a cell model, cisplatin-resistant OC-3-VGH cells expressed a lower level of PR-B than wild-type cells. Overexpression of PR-B or progesterone could increase cisplatin sensitivity in both OC-3-VGH and OVCAR-3 cells via the mechanism of promoting cisplatin-related apoptosis. Conclusions: When compared to weak PR-B, ovarian HGSC patients with a strong PR-B expression had a better chance of platinum sensitivity and survival, and this finding was compatible with our experimental results. Progesterone seemed to be a platinum sensitizer, but the value of adding progesterone in the treatment of ovarian HGSC should be further investigated.

A Real-World Evidence Study of CDK4/6 Inhibitor Treatment Patterns and Outcomes in Metastatic Breast Cancer by Germline BRCA Mutation Status

Introduction

Limited data exist on real-world treatment patterns and the effectiveness of cyclin-dependent kinase (CDK) 4/6 inhibitors in germline BRCA (gBRCA)-mutated breast cancer.

Methods

Adults with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2−) metastatic breast cancer (mBC) treated with CDK4/6 inhibitor therapy between 2013 and 2018 were retrospectively selected from the Flatiron Health database. Patients with known gBRCA status were classified as mutated (gBRCAm) or wild type (gBRCAwt). Time-to-first subsequent therapy or death (TFST) and overall survival (OS) were calculated from the earliest line of therapy with a CDK4/6 inhibitor.

Results

Of 2968 patients with HR+/HER2− mBC receiving a CDK4/6 inhibitor, 859 (28.9%) had known gBRCA status, of whom 9.9% were gBRCAm and 90.1% gBRCAwt. Median (95% confidence interval [CI]) TFST was 10 (7–11) months in the gBRCAm group, 10 (9–11) months in the gBRCAwt group, and 11 (10–12) months in the combined gBRCAwt and unknown gBRCA group; median (95% CI) OS was 26 (21–not estimated), 37 (31–51), and 33 (31–35) months, respectively. Cox models indicated the gBRCAm group had shorter TFST (stratified hazard ratio [sHR] 1.24; 95% CI 0.96–1.59) and OS (sHR 1.50; 95% CI 1.06–2.14) than the gBRCAwt group. The gBRCAm group had shorter TFST (sHR 1.38; 95% CI 1.08–1.75) and OS (sHR 1.22; 95% CI 0.88–1.71) than the combined group.

Conclusion

The results of this real-world study suggest that treatment outcomes with CDK4/6 inhibitors may be worse in patients with gBRCAm mBC than in their counterparts with gBRCAwt and unknown gBRCA status, suggesting potential differences in tumor biology. This result highlights the unmet need in patients with gBRCAm requiring optimized treatment selection and sequencing. Future exploration in larger samples of patients who have had biomarker testing is warranted.

High-dose tamoxifen in high-hormone-receptor-expressing advanced breast cancer patients: a phase II pilot study

Background

Tumor progression following endocrine therapy is considered to indicate resistance to endocrine drugs due to a variety of mechanisms. An insufficient dose of endocrine drugs is one of the causes for treatment failure in some patients with high hormone-receptor (HR)-expressing advanced breast cancer. This study aimed to explore the efficacy of high-dose tamoxifen (TAM) treatment in patients with advanced breast cancer with highly expressed HR.

Materials & methods

This was a single-arm, phase II pilot study that enrolled patients with advanced breast cancer with high HR expression (estrogen receptor ⩾60% and/or progesterone receptor ⩾60%) following routine endocrine therapy. All enrolled patients received a high-dose of TAM (100 mg/day) until disease progression. The primary endpoint was progression-free survival (PFS). The secondary endpoints included objective response rate (ORR), clinical benefit rate (CBR), overall survival (OS), and safety. Exploratory endpoints included the predictive value of ¹⁶α-¹⁸F-¹⁷β-fluoroestradiol quantitative positron emission tomography/computed tomography (¹⁸F-FES PET/CT) for treatment efficacy.

Results

A total of 30 patients were enrolled between September 2017 and February 2019. The median PFS was 6 months [95% confidence interval (CI) 4.9-7.1] and the median OS was 15.6 months (95% CI 8.3-22.9). Five patients experienced a partial response (PR) and none experienced a complete response (CR), with an ORR of 16.7% and CBR of 33.3%. No severe adverse events were observed. Lesions with ¹⁸F-FES maximum standardized uptake value (SUVmax) ⩾4 had a significantly longer PFS [median 9.2 months, (95% CI 6.9-11.6)] compared with lesions with a ¹⁸F-FES SUVmax <4 [median 4.8 months, (95% CI 3.9-5.6); p = 0.022].

Conclusion

A high-dose of TAM is effective and safe for patients with advanced breast cancer with high HR expression. ¹⁸F-FES SUVmax values may predict the local clinical benefits of high-dose TAM .

Trial Registration

[ClinicalTrials.gov identifier: NCT0304565].

Methylome Variation Predicts Exemestane Resistance in Advanced ER+ Breast Cancer

Background:

More than 30% of estrogen receptor-positive breast cancers are resistant to primary hormone therapy, and about 40% that initially respond to hormone therapy eventually acquire resistance. Although the mechanisms of hormone therapy resistance remain unclear, aberrant DNA methylation has been implicated in oncogenesis and drug resistance.

Purpose:

We investigated the relationship between methylome variations in circulating tumor DNA and exemestane resistance, to track hormone therapy efficacy.

Methods:

We prospectively recruited 16 patients who were receiving first-line therapy in our center. All patients received exemestane-based hormone therapy after enrollment. We collected blood samples at baseline, first follow-up (after 2 therapeutic cycles) and at detection of disease progression. Disease that progressed within 6 months under exemestane treatment was considered exemestane resistance but was considered relatively exemestane-sensitive otherwise. We obtained circulating tumor DNA-derived methylomes using the whole-genome bisulfide sequencing method. Methylation calling was done by BISMARK software; differentially methylated regions for exemestane resistance were calculated afterward.

Results:

Median follow-up for the 16 patients was 19.0 months. We found 7 exemestane resistance-related differentially methylated regions, located in different chromosomes, with both significantly different methylation density and methylation ratio. Baseline methylation density and methylation ratio of chromosome 6 [32400000-32599999] were both high in exemestane resistance. High baseline methylation ratios of chromosome 3 [67800000-67999999] (P = .013), chromosome 3 [140200000-140399999] (P = .037), and chromosome 12 [101200000-101399999] (P = .026) could also predict exemestane resistance. During exemestane treatment, synchronized changes in methylation density and methylation ratio in chromosome 6 [32400000-32599999] could accurately stratify patients in terms of progression-free survival (P = .000033). Cutoff values of methylation density and methylation ratio for chromosome 6 [149600000-149799999] were 0.066 and 0.076, respectively.

Conclusion:

Methylation change in chromosome 6 [149600000-149799999] is an ideal predictor of exemestane resistance with great clinical potential.

High Expression of Asparagine Synthetase Is Associated with Poor Prognosis of Breast Cancer in Chinese Population

Aims: This study aimed to determine the expression of asparagine synthetase (ASNS) in breast cancer (BC) tissues and estimate its prognostic value for BC patients. Besides, the roles of ASNS in the proliferation of BC cells were also examined in the study. Methods: Quantitative real-time PCR was conducted to detect the expression of ASNS mRNA in BC tissues and normal controls. The relationship between ASNS expression and clinical characteristics of BC patients was analyzed using χ-square test. MTT assay was performed to explore the effect of ASNS expression on the proliferation of BC cells. Kaplan-Meier curves were plotted to describe the overall survival rate of BC patients. Cox regression analyses were implemented to investigate prognostic factors. Results: ASNS mRNA overexpression was observed in BC tissues (p < 0.05). High expression of ASNS was significantly related to histological grade (p = 0.017), vascular invasion (p = 0.009), and PR status (p = 0.014). The downregulation of ASNS affected the proliferation of BC cells (p < 0.05). Kaplan-Meier survival showed that patients with high ASNS expression lived shorter than those with low expressions (p < 0.001). Finally, Cox regression analyses revealed that ASNS could act as a prognostic marker for BC patients (p < 0.001, HR = 3.293, 95% CI = 1.790-6.058). Conclusion: Taken together, ASNS is a valuable prognostic biomarker for BC patients.

Low Dose of Paclitaxel Combined with XAV939 Attenuates Metastasis, Angiogenesis and Growth in Breast Cancer by Suppressing Wnt Signaling

Triple-negative breast cancer (TNBC) accounts for 15% of overall breast cancer. A lack of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2 receptor) makes TNBC more aggressive and metastatic. Wnt signaling is one of the important pathways in the cellular process; in TNBC it is aberrantly regulated, which leads to the progression and metastasis. In this study, we designed a therapeutic strategy using a combination of a low dose of paclitaxel and a Wnt signaling inhibitor (XAV939), and examined the effect of the paclitaxel-combined XAV939 treatment on diverse breast cancer lines including TNBC cell lines (MDA-MB-231, MDA-MB-468, and BT549) and ER+ve cell lines (MCF-7 and T-47D). The combination treatment of paclitaxel (20 nM) and XAV939 (10 µM) exerted a comparable therapeutic effect on MDA-MB-231, MDA-MB-468, BT549, MCF-7, and T-47D cell lines, relative to paclitaxel with a high dose (200 nM). The paclitaxel-combined XAV939 treatment induced apoptosis by suppressing Bcl-2 and by increasing the cleavage of caspases-3 and PARP. In addition, the in vivo results of the paclitaxel-combined XAV939 treatment in a mice model with the MDA-MB-231 xenograft further confirmed its therapeutic effect. Furthermore, the paclitaxel-combined XAV939 treatment reduced the expression of β-catenin, a key molecule in the Wnt pathway, which led to suppression of the expression of epithelial-mesenchymal transition (EMT) markers and angiogenic proteins both at mRNA and protein levels. The expression level of E-cadherin was raised, which potentially indicates the inhibition of EMT. Importantly, the breast tumor induced by pristane was significantly reduced by the paclitaxel-combined XAV939 treatment. Overall, the paclitaxel-combined XAV939 regimen was found to induce apoptosis and to inhibit Wnt signaling, resulting in the suppression of EMT and angiogenesis. For the first time, we report that our combination approach using a low dose of paclitaxel and XAV939 could be conducive to treating TNBC and an external carcinogen-induced breast cancer.

LINC00309 is associated with short disease-free survival in breast cancer

Background

Long non-coding RNAs play an important role in breast cancer. Even with adjuvant hormone therapy, patients with estrogen receptor positive breast cancer can present with recurrences and distant metastases. We investigated whether the expression of a novel long non-coding RNA LINC00309 can predict the outcome of breast cancer, especially for hormone-receptor positive patients.

Methods

This retrospective study collected 290 breast cancer patients including 161 patients with hormone-positive. qPCR was performed to detect the expression of LINC00309. Kaplan–Meier and Cox risk proportion model were applied to disclose the function of LINC00309 for breast cancer prognosis.

Results

LINC00309 high expression was an independent predictor for worse disease-free survival (HR = 2.127; 95% CI 1.074–4.212; p = 0.030) and associated with a shorter disease-free survival (p = 0.027), especially in hormone-positive breast cancer patients (p = 0.001). Also LINC00309 high expression was associated with a shorter disease-free survival both in selective estrogen receptor modulator related hormone therapy (p = 0.025) and aromatase inhibitors related hormone therapy (p = 0.048). Moreover, LINC00309 was an independent predictor of worse disease-free survival in hormone-receptor positive breast cancer patients on univariate (HR = 4.505; 95% CI 1.722–11.785; p = 0.002) and multivariate (HR = 4.159; 95% CI 1.537–11.251; p = 0.005) analyses.

Conclusion

In breast cancer, Linc00309 is significantly associated with poor prognosis and may represent a new marker of prognosis.

Electronic supplementary material

The online version of this article (10.1186/s12935-019-0887-x) contains supplementary material, which is available to authorized users.

EGCG-Derivative G28 Shows High Efficacy Inhibiting the Mammosphere-Forming Capacity of Sensitive and Resistant TNBC Models

Recent studies showed that Fatty Acid Synthase (FASN), a lipogenic enzyme overexpressed in several carcinomas, plays an important role in drug resistance. Furthermore, the enrichment of Breast Cancer Stem Cell (BCSC) features has been found in breast tumors that progressed after chemotherapy. Hence, we used the triple negative breast cancer (TNBC) cell line MDA-MB-231 (231) to evaluate the FASN and BCSC population role in resistance acquisition to chemotherapy. For this reason, parental cell line (231) and its derivatives resistant to doxorubicin (231DXR) and paclitaxel (231PTR) were used. The Mammosphere-Forming Assay and aldehyde dehydrogenase (ALDH) enzyme activity assay showed an increase in BCSCs in the doxorubicin-resistant model. Moreover, the expression of some transcription factors involved in epithelial-mesenchymal transition (EMT), a process that confers BCSC characteristics, was upregulated after chemotherapy treatment. FASN inhibitors C75, (−)-Epigallocatechin 3-gallate (EGCG), and its synthetic derivatives G28, G56 and G37 were used to evaluate the effect of FASN inhibition on the BCSC-enriched population in our cell lines. G28 showed a noticeable antiproliferative effect in adherent conditions and, interestingly, a high mammosphere-forming inhibition capacity in all cell models. Our preliminary results highlight the importance of studying FASN inhibitors for the treatment of TNBC patients, especially those who progress after chemotherapy.

Current status of PI3K-mTOR inhibition in hormone-receptor positive, HER2-negative breast cancer

Breast cancer (BC) is the most common cancer in women and second only to lung cancer in terms of mortality. Among the three different BC subtypes, the oestrogen receptor positive represents nearly 70% of all cases and it is usually treated with anti-oestrogen drugs. However, the majority of hormone receptor positive metastatic BC patients develop resistance to anti-oestrogen treatments. The need for more down-stream therapies brought to the development of therapeutic strategies inhibiting the phosphatidylinositol 3-kinase-mammalian target of rapamycin (mTOR) pathway. Inhibitors of the mTOR have been tested in different clinical trials; everolimus has been Food and Drug Administration approved for the treatment of oestrogen receptor positive/human epidermal growth factor receptor 2 negative BC patients in combination with exemestane in patients who have progressed to anastrozole or letrozole after the encouraging results coming from BOLERO-2 trial. Similar results were obtained by the TAMRAD investigatory study testing tamoxifen in combination with everolimus in advanced BC. This editorial focuses on the results from BOLERO-2, BOLERO 4 and BOLERO-6, which tested the clinical importance of mTOR inhibition. We comment also on the role of phosphatidylinositol 3-kinase-mTOR inhibition as reported in the BELLE-2 and BELLE-3 trials and the future directions for the inhibition of this tumour metabolic axis.

FOXA1 levels are decreased in pleural breast cancer metastases after adjuvant endocrine therapy, and this is associated with poor outcome

Estrogen receptor-alpha (ERα)-positive breast cancer is often treated with antihormonal regimens. However, resistance to treatment is common, leading to metastatic disease. ERα activity requires the functional involvement of pioneer factors FOXA1 and GATA3, which enable ERα-chromatin binding and are crucial for ERα-driven cell proliferation. FOXA1 was found increased in metastatic breast cancers in relation to the primary tumor, but a comprehensive clinical assessment thereof, in relation to different metastatic sites and endocrine therapy usage, is currently lacking. Prior cell line-based reports, however, have revealed that FOXA1 is required for tamoxifen-resistant tumor cell proliferation. We studied expression levels of ERα, GATA3, and FOXA1 by immunohistochemistry in samples from both primary tumors and various metastatic sites. For all factors, expression levels varied between the metastatic sites. For pleural metastases, strong variation was found in FOXA1 and GATA3 levels. Although GATA3 levels remained unaltered between primary breast cancer and pleural metastases, FOXA1 levels were reduced exclusively in metastases of patients who received endocrine therapies in the adjuvant setting, even though ERα was still expressed. Importantly, decreased FOXA1 levels in pleural metastases correlated with hormone irresponsiveness in the palliative setting, while no such correlation was found for GATA3. With this, we show divergent clinical correlations of the two ERα pioneer factors FOXA1 and GATA3 in metastatic breast cancer, where endocrine therapy resistance was associated with decreased FOXA1 levels in pleural metastases.

16-Hydroxycleroda-3,13-dien-15,16-olide and N-Methyl-Actinodaphine Potentiate Tamoxifen-Induced Cell Death in Breast Cancer

In this study, we investigated whether 16-hydroxycleroda-3,13-dien-15,16-olide (HCD) and N-methyl-actinodaphine (MA) could sensitize breast cancer cells to Tamoxifen (TMX) treatment. MA or HCD alone or in combination with TMX dose-dependently inhibited MCF-7 and MDA-MB-231 cell growth, with a more potent inhibition on MDA-MB 231 cells. Furthermore, this novel combination significantly induced S and G2/M cell cycle phase in MDA-MB 231 than MCF-7 cells. Further determination of the apoptotic induction showed that MA or HCD and TMX combination inhibited MDA-MB-231 and MCF-7 cancer cells by upregulating Bax and by downregulating Bcl-2 mRNA and protein expression without altering Caspase-8 and Caspase-12 expression. These results suggest that MA or HCD pretreatment may potentiate the anti-tumor effect of tamoxifen on breast cancer.

Mutational Profile of Metastatic Breast Cancer Tissue in Patients Treated with Exemestane Plus Everolimus

Background

Everolimus has been shown to overcome endocrine resistance in hormone receptor positive advanced breast cancer patients. Predictive biomarkers of everolimus efficacy have been investigated in primary breast cancer tissue without finding univocal results. The goal of this study was to investigate the mutational burden in the metastatic site of endocrine-resistant tumors treated with everolimus plus exemestane.

Patients and Methods

Mass Array Sequenom platform was used to analyse genetic status of 18 cancer-related genes in 25 archival tumor specimens from metastatic lesions and available primary matched breast cancer tissue of patients treated with everolimus and exemestane for advanced disease. An exploratory analysis of everolimus efficacy in terms of progression free survival benefit and single gene mutation was carried out.

Results

The overall detection rate of mutation was 30% and 38% from metastatic and primary breast cancer samples, respectively. AKT1^E17K was the most frequent mutated gene. No primary breast cancer and matched relapse maintained the same mutation profile. Considering molecular pathways, the most of the genes belong to PI3K pathway (AKT1^E17K, PI3KCA^E545K, and KIT^G565R,S709F). In patients with detected mutations in breast and/or recurrence tissue the median PFS was 5,6 months while in the subgroup of patients with no mutations the median PFS was 7,5 months.

Conclusions

The mutational status of breast cancer recurrence allows the identification of some genes potentially correlating tumor response/resistance to everolimus. The most frequently mutated genes were involved in the PI3K/AKT/mTOR pathway highlighting that the deregulation of this pathway in the relapse plays a crucial role in the mechanisms of everolimus resistance/sensitivity. Owing to the small sample size and the retrospective nature of the study, these correlations need to be validated in a large prospective study.

Meeting the needs of breast cancer: A nucleolin's perspective

A major challenge in the management of breast cancer disease has been the development of metastases. Finding new molecular targets and the design of targeted therapeutic approaches to improve the overall survival and quality of life of these patients is, therefore, of great importance. Nucleolin, which is overexpressed in cancer cells and tumor-associated blood vessels, have been implicated in various processes supporting tumorigenesis and angiogenesis. Additionally, its overexpression has been demonstrated in a variety of human neoplasias as an unfavorable prognostic factor, associated with a high risk of relapse and low overall survival. Hence, nucleolin has emerged as a relevant target for therapeutic intervention in cancer malignancy, including breast cancer. This review focus on the contribution of nucleolin for cancer disease and on the development of therapeutic strategies targeting this protein. In this respect, it also provides a critical analysis about the potential and pitfalls of nanomedicine for cancer therapy.

Pharmacogenomic Discovery to Function and Mechanism: Breast Cancer as a Case Study

Biomedical research is undergoing rapid change, with the development of a series of analytical omics techniques that are capable of generating Biomedical Big Data. These developments provide an unprecedented opportunity to gain novel insight into disease pathophysiology and mechanisms of drug action and response-but they also present significant challenges. Pharmacogenomics is a discipline within Clinical Pharmacology that has been at the forefront in defining, taking advantage of, and dealing with the opportunities and challenges of this aspect of the Post-Genome Project world. This overview will describe the evolution of germline pharmacogenomic research strategies as we have moved from an era of candidate genes to agnostic genome-wide association studies (GWAS) coupled with the functional and mechanistic pursuit of GWAS signals. Germline pharmacogenomic studies of breast cancer endocrine therapy will be used to illustrate research strategies that are being applied broadly to omics studies of drug response phenotypes.

Identification of the SOX2 Interactome by BioID Reveals EP300 as a Mediator of SOX2-dependent Squamous Differentiation and Lung Squamous Cell Carcinoma Growth

Lung cancer is the leading cause of cancer mortality worldwide, with squamous cell carcinoma (SQCC) being the second most common form. SQCCs are thought to originate in bronchial basal cells through an injury response to smoking, which results in this stem cell population committing to hyperplastic squamous rather than mucinous and ciliated fates. Copy number gains in SOX2 in the region of 3q26-28 occur in 94% of SQCCs, and appear to act both early and late in disease progression by stabilizing the initial squamous injury response in stem cells and promoting growth of invasive carcinoma. Thus, anti-SOX2 targeting strategies could help treat early and/or advanced disease. Because SOX2 itself is not readily druggable, we sought to characterize SOX2 binding partners, with the hope of identifying new strategies to indirectly interfere with SOX2 activity. We now report the first use of proximity-dependent biotin labeling (BioID) to characterize the SOX2 interactome in vivo We identified 82 high confidence SOX2-interacting partners. An interaction with the coactivator EP300 was subsequently validated in both basal cells and SQCCs, and we demonstrate that EP300 is necessary for SOX2 activity in basal cells, including for induction of the squamous fate. We also report that EP300 copy number gains are common in SQCCs and that growth of lung cancer cell lines with 3q gains, including SQCC cells, is dependent on EP300. Finally, we show that EP300 inhibitors can be combined with other targeted therapeutics to achieve more effective growth suppression. Our work supports the use of BioID to identify interacting protein partners of nondruggable oncoproteins such as SOX2, as an effective strategy to discover biologically relevant, druggable targets.

Advances in systemic therapy for metastatic breast cancer: future perspectives

Breast cancer (BC) is the most common cancer in women worldwide. One in eight women will develop the disease in her lifetime. Notwithstanding the incredible progress made in this field, BC still represents the second most common cause of cancer-related death in women. Targeted drugs have revolutionised breast cancer treatment and improved the prognosis as well as the life expectancy of millions of women. However, the phenomenon of primary and secondary pharmacological resistance is becoming increasingly evident, limiting the efficacy of these agents and calling for a better in-depth knowledge and understanding of the biology as well as the biochemical crosstalk underlying the disease. The advent of laboratory technologies in the clinical setting such as the routine use of next generation sequencing has allowed identification of new genetic alterations as well as providing a precise picture of the molecular landscapes of each tumour. Consequently, new specific therapeutic approaches are becoming available to minimise or delay the occurrence of resistance. In this review, we analyse the latest research and news from the clinical development side for each BC subtype.

What is known about melatonin, chemotherapy and altered gene expression in breast cancer

Melatonin, synthesized in and released from the pineal gland, has been demonstrated by multiple in vivo and in vitro studies to have an oncostatic role in hormone-dependent tumors. Furthermore, several clinical trials point to melatonin as a promising adjuvant molecule to be considered for cancer treatment. In the past few years, evidence of a broader spectrum of action of melatonin as an antitumor agent has arisen; thus, melatonin appears to also have therapeutic effects in several types of hormone-independent cancer, including ovarian, leukemic, pancreatic, gastric and non-small cell lung carcinoma. In the present study, the latest findings regarding melatonin molecular actions when concomitantly administered with either radiotherapy or chemotherapy in cancer were reviewed, with a particular focus on hormone-dependent breast cancer. Finally, the present study discusses which direction should be followed in the next years to definitely clarify whether or not melatonin administration could protect against non-desirable effects (such as altered gene expression and post-translational protein modifications) caused by chemotherapy or radiotherapy treatments. As treatments move towards personalized medicine, comparative gene expression profiling with and without melatonin may be a powerful tool to better understand the antitumor effects of melatonin, the pineal gland hormone.

Plumbagin sensitizes breast cancer cells to tamoxifen-induced cell death through GRP78 inhibition and Bik upregulation

The glucose regulated protein 78 (GRP78) is a major chaperone of the endoplasmic reticulum, and a prosurvival component of the unfolded protein response. GRP78 is upregulated in many types of cancers, including breast cancer. Research has suggested that GRP78 overexpression confers chemoresistance to anti-estrogen agents through a mechanism involving the inhibition of a pro-apoptotic BH3-only protein, Bik. In the present research the role of plumbagin, a naturally occurring naphthoquinone, in GRP78-associated cell death inhibition was examined. The results demonstrated that plumbagin inhibits GRP78 activity and GRP78 inhibition contributes to plumbagin-mediated cell death induction. Furthermore, Bik upregulation was associated with plumbagin-induced cell death and an increase in plumbagin-mediated Bik induction was observed upon GRP78 downregulation. Plumbagin sensitized estrogen-positive breast cancer cells to tamoxifen and the association of GRP78 inhibition and Bik upregulation in plumbagin-mediated cell sensitization was shown. Collectively, the results of this research suggest that plumbagin inhibits the antiapoptotic activity of GRP78 leading to Bik upregulation and apoptosis induction, which contributes to the sensitization of breast cancer cells to tamoxifen.

Predicting and Overcoming Chemotherapeutic Resistance in Breast Cancer

Our understanding of breast cancer and its therapeutic approach has improved greatly due to the advancement of molecular biology in recent years. Clinically, breast cancers are characterized into three basic types based on their immunohistochemical properties. They are triple-negative breast cancer, estrogen receptor (ER) and progesterone receptor (PR)-positive-HR positive breast cancer, and human epidermal growth factor receptor 2 (HER2)-positive breast cancer. Even though these subtypes have been characterized, assessment of a breast cancer's receptor status is still widely used to determine whether or not a targeted therapy could be applied. Moreover, drug resistance is common in all breast cancer types despite the different treatment modalities applied. The development of resistance to different therapeutics is not mutually exclusive. It seems that tumor could be resistant to multiple treatment strategies, such as being both chemoresistant and monoclonal antibody resistant. However, the underlying mechanisms are complicated and need further investigation. In this chapter, we aim to provide a brief review of the different types of breast cancer and their respective treatment strategies. We also review the possible mechanisms of potential drug resistance associated with each treatment type. We believe that a better understanding of the drug resistance mechanisms can lead to a more effective and efficient therapeutic success.

Chemosensitization role of fulvestrant in combination with chemotherapy in postmenopausal hormone receptor positive and human epidermal growth factor negative metastatic breast cancer

In metastatic breast cancer (MBC), hormone receptor positive (HR+), human epidermal growth factor negative (HER2-) subtype accounts for the majority. With various new modalities available to prolong life span in this group of patients, the effect is distant from optimum. Prevalent strategy of treating postmenopausal HR+ HER2- MBC is application of chemotherapy (CT) after progression of disease on endocrine therapy (ET) of several lines. Generally, ET targets HR+ ingredients and CT works better with HR- tumor cells. HR+ MBC, though hormone-sensitive, has HR- portion which reacts poorly to ET. Thus, sequential use of ET and CT neglects its insensitive part and gives rise to drug resistance, while alleviation of tumor burden is the top priority in metastatic setting. Chemohormonal therapy (i.e. concomitant use of ET and chemotherapy) complements for the shortcoming of current therapy strategy targeting both HR+ and HR- ingredients theoretically. Fulvestrant, a pure estrogen receptor antagonist and down-regulator, could be a promising agent using concurrently with CT based on chemosensitizing character shown in preclinical and pilot clinical studies. It is hypothesized in this article that chemohormonal therapy with concurrent fulvestrant and CT would be a promising strategy in postmenopausal HR+ HER2- MBC patients. Proof of this hypothesis would help control evolvement of tumor burden and acquirement of drug resistance over a short period of time.

Strategies in functional proteomics: Unveiling the pathways to precision oncology

Personalised strategies in cancer care are required to overcome the therapeutic challenges posed by variability between patients and disease subsets. To this end, enhanced precision tools must be developed to describe the molecular drivers of malignant proliferation. Such tools must also identify druggable targets and biomarkers in order to provide essential information regarding drug development and therapeutic outcome. Here we discuss how proteomics-based approaches provide a set of viable methodologies capable of delivering quantitative information throughout the main stages of personalised oncology and a ratiometric platform that delivers systems-wide methods for drug evaluation.

Cyclin-Dependent Kinase Inhibitors for the Treatment of Breast Cancer: Past, Present, and Future

Treatment of metastatic breast cancer (MBC) that is resistant to endocrine therapy presents a significant clinical challenge. The well-known role of cell cycle dysregulation in these patients is partly mediated by cyclin-dependent kinase (CDK) activity. Specific cyclin and CDK complexes regulate cell cycle progression by managing the transition through the cell cycle, and inhibition of CDKs represents an important target for novel agents. First-generation CDK inhibitors (e.g., flavopiridol) were relatively nonselective and had an unacceptable toxicity profile in early trials. Second-generation CDK inhibitors were designed to target the CDK4 and CDK6 (CDK4/6) pathway and have shown promising clinical activity with an acceptable toxicity profile in patients with MBC. Palbociclib is a first-in-class CDK4/6 inhibitor that was granted accelerated U.S. Food and Drug Administration approval in combination with letrozole for the treatment of MBC in the first-line setting (February 2015) as well as in combination with fulvestrant for MBC that had progressed on previous endocrine therapy (February 2016). Other CDK4/6 inhibitors, including ribociclib and abemaciclib, are under investigation as monotherapy and in combination with endocrine or anti-human epidermal growth receptor 2 therapy for the treatment of MBC. Ongoing clinical trials should provide additional information to guide the appropriate use of these agents and identify patient populations that could derive the most benefit.

Obesity and Breast Cancer: Molecular Interconnections and Potential Clinical Applications

Obesity is an important risk factor for breast cancer (BC) in postmenopausal women; interlinked molecular mechanisms might be involved in the pathogenesis. Increased levels of estrogens due to aromatization of the adipose tissue, inflammatory cytokines such as tumor necrosis factor-α, interleukin-6, and prostaglandin E2, insulin resistance and hyperactivation of insulin-like growth factors pathways, adipokines, and oxidative stress are all abnormally regulated in obese women and contribute to cancerogenesis. These molecular factors interfere with intracellular signaling in the mitogen-activated protein kinase and phosphatydilinositol-3-phosphate/mammalian target of rapamycin (mTOR) pathways, which regulate the progression of the cell cycle, apoptosis, and protein synthesis. In this context, structural defects of typical genes related to both BC and obesity, such as leptin, leptin receptor, serum paraoxonase/arylesterase 1, the fat mass and obesity-associated gene and melanocortin receptor 4, have been associated with a high or low risk of BC development. The early detection of these gene alterations might be useful as risk predictors in obese women, and targeting these pathways involved in the BC pathogenesis in obese women is a potential therapeutic tool. In particular, mTOR pathway deregulation concurs in both obesity and BC, and inhibition of this might disrupt the molecular interlinks in a similar manner to that of metformin, which exerts definite anticancer activity and is currently used as an antidiabetic drug with a weight-reducing property. The identification of both genetic and pharmacological implications on the prevention and management of BC is the ultimate aim of these studies.

IMPLICATIONS FOR PRACTICE

Obese women are at risk of breast cancer, but clinicians lack concrete tools for the prevention or early diagnosis of this risk. The present study, starting from the biology and the molecular defects characterizing both obesity and breast cancer, analyzed the potential molecules and genetic defects whose early identification could delineate a risk profile. Three steps are proposed that are potentially achievable in the clinical assessment of obese women, namely the evaluation of altered levels of serum molecules, the identification of genetic polymorphisms, and the study of the transcriptomic profile of premalignant lesions. Finally, the therapeutic implications of this molecular assessment were evaluated.

Use of Palliative Endocrine Therapy in Patients with Hormone Receptor-Positive Distant Metastatic Breast Cancer: How Often, How Effective, How Long?

BACKGROUND

This study provides real-world clinical evidence regarding palliative endocrine therapy (ET) in breast cancer (BC). The main questions to be answered were: how often and how long did patients receive ET? A particular aspect was the analysis of compliance and persistence with ET.

METHODS

An analysis of a nonselected/consecutive cohort of women with distant metastatic hormone receptor-positive BC (n = 205) was conducted.

RESULTS

In all, 165 patients (80.5%) received ET during the palliative disease course. The noncompliance rate was 1.5%. Sixty-seven patients (40.6%) had ET as the only antineoplastic therapy. The median number of therapy lines was 2, and the median duration was 18 months. The median metastatic disease survival (MDS) was 34 months. In patients who had an MDS of ≥9 months (n = 145; 87.9%), during 70.6% of the MDS time only ET had been administered. Patients who were naïve to ET more often had a good response to and a longer duration of palliative ET than those who were not. The nonpersistence rate was 4.3%.

CONCLUSIONS

Excluding the few patients who had a rapidly progressive course, the disease was controlled for about 70% of the entire palliative disease course with ET alone. Only very few patients were nonpersistent with ET and consciously stopped a still effective, ongoing ET.