Implications For Treatment Of Breast Cancer Research Articles

Abstract SoA2-01: Cellular senescence: The senescence-associated secretory phenotype (SASP) and immunity

Abstract Cellular senescence is a stress-induced program following aberrant oncogene activation or administration of cancer therapies, including chemotherapeutic agents and CDK4/6 inhibitors commonly used for treating advanced breast cancers, that results in the proliferative arrest of damaged cells and induction of the senescence associated secretory phenotype (SASP). The SASP involves secretion of inflammatory cytokines and chemokines and upregulation of immunomodulatory cell surface molecules on senescent cells that can promote their clearance by the immune system and tumor resolution. However, if left unchecked, the chronic SASP can also lead to immune suppression and further tissue damage that drives tumor dissemination and metastasis. Here we will discuss our efforts to understand how the SASP can promote anti-tumor immunity and immunotherapy activity in some cancer contexts yet in others immune suppression and tumor promotion. Our findings in other solid tumor contexts demonstrate that the tissue microenvironment has a profound impact of the type of SASP program activated and SASP-mediated immune responses produced and suggest further therapeutic interventions to remodel the SASP for immune control of cancer. Moreover, our results in other hormone-driven cancers suggest that CDK inhibitor and chemotherapy regimens produce different SASPs and resulting effects on myeloid cell and lymphocyte phenotypes that could explain their varying effects on anti-tumor immunity and treatment outcomes. Collectively these findings have important implications for breast cancer treatment and pave the path for rationale combination therapies with senescence-inducing agents to achieve immune control in breast and other immunologically “cold” solid tumor malignancies that are generally unresponsive to current immunotherapy regimens. Citation Format: M. Ruscetti. Cellular senescence: The senescence-associated secretory phenotype (SASP) and immunity [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr SoA2-01.

Internal mammary node positivity and autologous mastectomy reconstruction: Implications for breast cancer treatment and aesthetic outcome

<strong>Introduction:</strong> External Beam Radiation Therapy (EBRT), a type of whole breast radiation therapy, has been widely used in patients with early-stage breast cancer, however it is associated with longer treatment periods and higher toxicity.

Mainstream genetic testing for breast cancer patients: early experiences from the Parkville Familial Cancer Centre.

The demand for genetic testing of hereditary breast cancer genes such as BRCA1 and BRCA2 has continued to increase with the lowering costs of testing, raised awareness in the general public, and implications for breast cancer treatment when a patient is identified as having a germline pathogenic variant. Historically within Australia, patients affected by high genetic risk breast cancers have been referred to a familial cancer centre (FCC) for assessment and testing, resulting in wait times for an appointment for pre- and post-test genetic counselling and an increased demand on the public-funded FCC. To improve patient access and pace of genetic testing, as well as refocus FCC resources, a mainstream clinical genetic testing program was rolled out in September 2017 through the Parkville FCC (PFCC) in Australia at 10 hospital sites. This program enables specialist doctors of eligible patients affected by breast cancer to arrange genetic testing directly at an oncology/surgical appointment and follow up the results as part of the patients' routine clinical care. In this model, the specialist doctor is responsible for any treatment implications of the genetic test result, and the PFCC is responsible for result interpretation, future cancer risk, family cascade testing and segregation testing where warranted. To date the program has had successful uptake, a notable pathogenic variant detection rate, reduced the burden on the PFCC enabling a reallocation of resources and has streamlined the process of genetic testing for eligible patients. Investigation into the patient and clinician experiences of the mainstream program is required.

Implications for breast cancer treatment from increased autotaxin production in adipose tissue after radiotherapy.

We have previously established that adipose tissue adjacent to breast tumors becomes inflamed by tumor-derived cytokines. This stimulates autotaxin (ATX) secretion from adipocytes, whereas breast cancer cells produce insignificant ATX. Lysophosphatidate produced by ATX promotes inflammatory cytokine secretion in a vicious inflammatory cycle, which increases tumor growth and metastasis and decreases response to chemotherapy. We hypothesized that damage to adipose tissue during radiotherapy for breast cancer should promote lysophosphatidic acid (LPA) signaling and further inflammatory signaling, which could potentially protect cancer cells from subsequent fractions of radiation therapy. To test this hypothesis, we exposed rat and human adipose tissue to radiation doses (0.25-5 Gy) that were expected during radiotherapy. This exposure increased mRNA levels for ATX, cyclooxygenase-2, IL-1β, IL-6, IL-10, TNF-α, and LPA1 and LPA2 receptors by 1.8- to 5.1-fold after 4 to 48 h. There were also 1.5- to 2.5-fold increases in the secretion of ATX and 14 inflammatory mediators after irradiating at 1 Gy. Inhibition of the radiation-induced activation of NF-κB, cyclooxygenase-2, poly (ADP-ribose) polymerase-1, or ataxia telangiectasia and Rad3-related protein blocked inflammatory responses to γ-radiation. Consequently, collateral damage to adipose tissue during radiotherapy could establish a comprehensive wound-healing response that involves increased signaling by LPA, cyclooxygenase-2, and other inflammatory mediators that could decrease the efficacy of further radiotherapy or chemotherapy.-Meng, G., Tang, X., Yang, Z., Benesch, M. G. K., Marshall, A., Murray, D., Hemmings, D. G., Wuest, F., McMullen, T. P. W., Brindley, D. N. Implications for breast cancer treatment from increased autotaxin production in adipose tissue after radiotherapy.

The ins and outs of calcium signalling in lactation and involution: Implications for breast cancer treatment

The mammary epithelium is highly responsive to hormonal and non-hormonal signalling cues for physiological growth, function and tissue remodelling. Whilst steroid hormones freely diffuse across the cell membrane to bind to intracellular hormone receptors, cell-impermeable ligands, including many peptide hormones, growth factors and cytokines, bind to receptors on the plasma membrane and relay their message via the specific activation of intracellular signal transduction pathways. A signalling pathway that is indispensable for decoding many extracellular signals into cellular responses is calcium (Ca2+). Changes in the expression of specific Ca2+ channels, pumps and binding proteins may therefore greatly alter the nature of the cellular response to various growth, morphogenetic and cell death stimuli. This review summarises changes in the expression, localisation and function of key Ca2+ channels and pumps in mammary epithelial cells during lactation and discusses how this altered Ca2+ handling may later expose these cells to targeted cell death during post-lactational involution. A greater understanding of the processes regulating the growth, death and regeneration of the mammary epithelium under physiological conditions may provide important insights into the proliferation and survival mechanisms underpinning malignant growth. The therapeutic manipulation of specific calcium signalling pathways in breast cancer cells to control aberrant cell proliferation and/or turnover represents an aim for the future.

The role of Nanog expression in tamoxifen-resistant breast cancer cells.

There is an accumulation of evidence that shows a significant role of cancer stem cells in tumor initiation, proliferation, relapse, and metastasis. Nanog is the most important core transcription marker of stem cells, known by its role in maintaining pluripotency, proliferation, and differentiation. Therefore, this study aimed to examine the role of Nanog in breast cancer cell tamoxifen resistance and its implications in breast cancer treatment. In this study, the expression of the three core transcription markers Nanog, Oct3/4, and Sox2 were quantitatively evaluated using flow cytometry. Then, small interfering RNA (siRNA) against human Nanog was transfected into tamoxifen-resistant breast cancer cells via Lipofectamine 2000. Nanog gene expression in the cells was detected using reverse transcription polymerase chain reaction (RT-PCR). The change in cell proliferation was evaluated using the tetrazolium bromide method. An enzyme-linked immunosorbent assay was used to detect apoptosis of the transfected cells alone and in combination with 4-hydroxytamoxifen. The results showed a high level expression of Nanog, Oct3/4, and Sox2 in MDA-MB-231 and MCF7/tamoxifen resistant cells compared with MCF7/wild-type. siRNA-mediated Nanog gene silencing can efficiently inhibit cell proliferation and induce apoptosis of tamoxifen-resistant breast cancer cells. This study provides a basis for further study of the role of Nanog in developing resistance to tamoxifen, its implication in breast cancer management, and as a new strategy to enhance response to endocrine therapy.

PG 7.01 The special case of “equivocal” pathological biomarkers (ER, PgR and HER2): Implications for breast cancer treatment

PG 7.01 The special case of “equivocal” pathological biomarkers (ER, PgR and HER2): Implications for breast cancer treatment

ER and PR Immunohistochemistry and HER2 FISH versus Oncotype DX: Implications for Breast Cancer Treatment

Estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor (HER2) concordance between immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH), and Oncotype DX, a commercially available RT-PCR-based assay which recently began reporting biomarker results was assessed. ER concordance was 98.9% (262/265), Pearson correlation coefficient (r) = 0.42, and Spearman's rank correlation (ρ) = 0.25. Positive percent agreement for ER was 98.9% (262/265). One patient with discordant ER results was not offered hormone therapy based on the preferential use of Oncotype DX. PR was concordant in 91.3% (242/265), r = 0.80, ρ = 0.75, and Cohen's kappa (κ) = 0.63. Positive percent agreement for PR was 90.5% (218/241) and negative percent agreement was 100% (24/24). HER2 concordance was 99.2% (245/247), r = 0.35, ρ = 0.28, and κ = 0.12. Positive percent agreement for HER2 was 0% (0/2) and negative percent agreement was 100% (245/245). Of the three FISH HER2-amplified cases, two were negative and one was equivocal, and all FISH HER2-equivocal cases (n = 3) were negative by Oncotype DX. Patients that were FISH HER2-amplified, Oncotype DX HER2-negative did not receive trastuzumab. Although our results demonstrated high concordance between IHC and Oncotype DX for ER and PR, our data showed poor positive percent agreement for HER2. Compared to FISH, Oncotype DX does not identify HER2-positive breast carcinomas. The preferential use of Oncotype DX biomarker results over IHC and FISH is discouraged.

Acquired Resistance to Tamoxifen Is Associated with Loss of the Type I Insulin-like Growth Factor Receptor: Implications for Breast Cancer Treatment

The role of the insulin-like growth factor (IGF) system in breast cancer is well defined, and inhibitors of this pathway are currently in clinical trials. The majority of anti-IGF1R clinical trials are in estrogen receptor-positive patients who have progressed on prior endocrine therapy; early reports show no benefit for addition of IGF1R inhibitors to endocrine therapy in this setting. In this study, we examined the effectiveness of IGF1R inhibitors in vitro by generating tamoxifen-resistant (TamR) cells. We found that TamR cells had diminished levels of IGF1R with unchanged levels of insulin receptor (IR), and failed to respond to IGF-I-induced Akt activation, proliferation, and anchorage-independent growth while retaining responsiveness to both insulin and IGF-II. The IGF1R antibody dalotuzumab inhibited IGF-I-mediated Akt phosphorylation, proliferation, and anchorage-independent growth in parental cells, but had no effect on TamR cells. An IGF1R tyrosine kinase inhibitor, AEW541, with equal potency for the IGF1R and IR, inhibited IGF-I-, IGF-II-, and insulin-stimulated Akt phosphorylation, proliferation, and anchorage-independent growth in parental cells. Interestingly, AEW541 also inhibited insulin- and IGF-II-stimulated effects in TamR cells. Tamoxifen-treated xenografts also had reduced levels of IGF1R, and dalotuzumab did not enhance the effect of tamoxifen. We conclude that cells selected for tamoxifen resistance in vitro have downregulated IGF1R making antibodies directed against this receptor ineffective. Inhibition of IR may be necessary to manage tamoxifen-resistant breast cancer.

Abstract 3584: Cardiovascular risk factors and co-morbid conditions among African-American and Caucasian breast cancer survivors

Abstract Background: African-American (AA) women experience poorer survival after a breast cancer diagnosis compared to Caucasian women. This difference persists even after taking into account access to care, tumor characteristics, and treatments. One possible explanation is that the racial disparity in survival after a breast cancer diagnosis is due to other co-morbid conditions that may worsen as a result of treatment. Of particular concern are cardiovascular-related co-morbidities that may contribute to morbidity and mortality among breast cancer patients treated with cardiotoxic agents. The present analysis examines racial differences in the prevalence of cardiovascular risk factors and co-morbid conditions among breast cancer survivors participating in a registry-based survey study. Methods: A self-administered survey was mailed to all cancer survivors listed in a hospital registry between 1996 and 2007. The surveys were returned by 851 women with a history of breast cancer who identified themselves as being either of AA (n = 121) or Caucasian (n = 730) race. Differences in cardiovascular risk factors and co-morbid conditions by race were examined using Student's t-tests and Chi-square tests. Results: The AA and Caucasian breast cancer survivors were similar in terms of age (AA 63.4 years, Caucasian 62.2 years; p=0.3) and years since diagnosis (AA 7.2, Caucasian 7.6; p=0.5) as well as the percentages receiving chemotherapy, radiation, and hormonal treatment. However, the AA breast cancer survivors were more likely than their Caucasian counterparts to be current smokers (12.1% versus 6.4%; p=0.02), to have a body mass index of &amp;gt;30 kg/m2 (55.8% versus 25.2%; p&amp;lt;0.01), and to report taking an anti-diabetic (18.2% versus 7.0%; p&amp;lt;0.01) or anti-hypertensive (61.2% versus 40.0%; p&amp;lt;0.01) medication. In addition, compared to the Caucasian breast cancer survivors, significantly more AA women reported having been diagnosed with diabetes (35.3% versus 10.1%; p&amp;lt;0.01), high cholesterol (60.0% versus 49.8%; p=0.04), or hypertension (73.3% versus 40.8%; p&amp;lt;0.01). Further, AA women were more likely that Caucasian women to report a history of a stroke (3.3% versus 1.0%; p=0.03), poor circulation (13.3% versus 6.2%; p&amp;lt;0.01) or blot clots (10.8% versus 5.9%; p=0.04). Conclusions: AA breast cancer survivors have a higher prevalence of cardiovascular disease risk factors and co-morbid conditions compared to Caucasian breast cancer survivors. The presence of these risk factors and co-morbidities may explain, in part, racial disparities in survival after a breast cancer diagnosis. If present at diagnosis, the presence of these cardiovascular co-morbidities may also have implications for breast cancer treatment, especially if planned therapies include those that increase a woman's risk of adverse cardiovascular outcomes. This research was supported, in part, by a grant from Susan G. Komen for the Cure. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3584. doi:1538-7445.AM2012-3584

Circulating tumor cells in HER-2 positive metastatic breast cancer patients treated with trastuzumab and chemotherapy

The detection of circulating tumor cells (CTCs) in peripheral blood may have important prognostic and predictive implications in breast cancer treatment. A limitation in this field has been the lack of a validated method of accurately measuring CTCs. While sensitivity has improved using RT-PCR, specificity remains a major challenge. The goal of this paper is to present a sensitive and specific methodology of detecting CTCs in women with HER-2 positive metastatic breast cancer, and to examine its role as a marker that tracks disease response during treatment with trastuzumab-containing regimens. The study included patients with HER-2-positive metastatic breast cancer enrolled on two different clinical protocols using a trastuzumab-containing regimen. Serial CTCs were measured at planned time points and clinical correlations were made. Immunomagnetic selection of circulating epithelial cells was used to address the specificity of tumor cell detection using cytokeratin 19 (CK19). In addition, the extracellular domain of the HER-2 protein (HER-2/ECD) was measured to determine if CTCs detected by CK19 accurately reflect tumor burden. The presence of CTCs at first restaging was associated with disease progression. We observed an association between CK19 and HER-2/ECD. The association of HER-2/ECD with clinical response followed a similar pattern to that seen with CK19. Finally, the absence of HER-2/ECD at best overall response and a change of HER-2/ECD from positive at baseline to negative at best overall response was associated with favorable treatment response. Our study supports the prognostic and predictive role of the detection of CTCs in treatment of HER-2-positive metastatic breast cancer patients. The association between CK19 and markers of disease burden is in line with the concept that CTCs may be a reliable measure of tumor cells in the peripheral blood of patients with metastatic breast cancer. The association of CTCs at first restaging with treatment failure indicates that CTCs may have a role as surrogate markers to monitor treatment response.

Circulating Tumor Cells in HER-2 Positive Metastatic Breast Cancer Patients Treated with Trastuzumab and Chemotherapy

The detection of circulating tumor cells (CTCs) in peripheral blood may have important prognostic and predictive implications in breast cancer treatment. A limitation in this field has been the lack of a validated method of accurately measuring CTCs. While sensitivity has improved using RT-PCR, specificity remains a major challenge. The goal of this paper is to present a sensitive and specific methodology of detecting CTCs in women with HER-2 positive metastatic breast cancer, and to examine its role as a marker that tracks disease response during treatment with trastuzumab-containing regimens. The study included patients with HER-2-positive metastatic breast cancer enrolled on two different clinical protocols using a trastuzumab-containing regimen. Serial CTCs were measured at planned time points and clinical correlations were made. Immunomagnetic selection of circulating epithelial cells was used to address the specificity of tumor cell detection using cytokeratin 19 (CK19). In addition, the extracellular domain of the HER-2 protein (HER-2/ECD) was measured to determine if CTCs detected by CK19 accurately reflect tumor burden. The presence of CTCs at first restaging was associated with disease progression. We observed an association between CK19 and HER-2/ECD. The association of HER-2/ECD with clinical response followed a similar pattern to that seen with CK19. Finally, the absence of HER-2/ECD at best overall response and a change of HER-2/ECD from positive at baseline to negative at best overall response was associated with favorable treatment response. Our study supports the prognostic and predictive role of the detection of CTCs in treatment of HER-2-positive metastatic breast cancer patients. The association between CK19 and markers of disease burden is in line with the concept that CTCs may be a reliable measure of tumor cells in the peripheral blood of patients with metastatic breast cancer. The association of CTCs at first restaging with treatment failure indicates that CTCs may have a role as surrogate markers to monitor treatment response.

La cellule souche cancéreuse

Recent research in a large variety of tumors, including breast cancer, has given support to the "cancer stem cell hypothesis". Based on this, tumors contain and are driven by a cellular subcomponent that retains key stem cell properties. These include self-renewal, which drives tumorigenesis, and the capacity to generate cellular heterogeneity. Recently, different techniques have been used to isolate potential breast cancer stem cells with the cell surface phenotype CD44+CD24-/low lin- or expressing Aldehyde dehydrogenase. This model has fundamental implications for breast cancer treatment. The development of specific therapeutics that target this population is an important focus for the future.

HER-2 gene amplification correlates with higher levels of angiogenesis and lower levels of hypoxia in primary breast tumors.

This study investigated the connection among HER-2 gene amplification, HER-2 protein expression, and markers of tumor angiogenesis and oxygenation in patients with operable, invasive breast tumors. From 1988 to 1995, 425 patients with metastatic breast cancer were enrolled in a study of high-dose chemotherapy with autologous transplant. Primary tumor blocks were obtained and evaluated using immunohistochemistry (IHC) staining of vessels with von Willebrand factor antibody. Mean microvessel densities (MVD) were determined by counting von Willebrand factor stained cells in three separate "vascular hot spots" using image analysis. Tumor samples were also stained for HER-2 by IHC, HER-2 gene amplification by fluorescence in situ hybridization, carbonic anhydrase 9 by IHC, and vascular endothelial growth factor (VEGF) by IHC. Plasma from 36 patients with primary tumor samples had VEGF (R&D Systems, MN) and d-dimer (American Diagnostica, Greenwich, CT) levels determined. There was a significant positive correlation between HER-2 gene amplification and both maximum and average MVD (Spearman coefficient = 0.51 and 0.50; P = 0.03 and 0.05, respectively). There was an inverse correlation with HER-2 gene amplification and expression of the tumor hypoxia marker CA-9 (chi(2) P = 0.02). The level of HER-2 gene amplification correlated with plasma d-dimer levels (Spearman coefficient = 0.43; P = 0.021). Interestingly, tumors with HER-2 by IHC had decreased amounts of VEGF staining (chi(2) = 5.81; P = 0.01). There was no correlation between HER-2 by IHC and MVD or d-dimer. Of all of the variables examined, only average (P = 0.0016) and maximum MVD (P = 0.0128) predicted disease-free survival (Cox univariate model). HER-2-amplified breast cancers have increased amounts of angiogenesis, decreased amounts of hypoxia, and increased markers of fibrin degradation. These findings have prognostic, predictive, and therapeutic implications in breast cancer treatment.