Development Of Human Breast Cancer Research Articles

Can Bovine Leukemia Virus Be Related to Human Breast Cancer? A Review of the Evidence

The incidence of breast cancer is continuously increasing worldwide, as influenced by many factors that act synergistically. In the last decade there was an increasing interest in the possible viral etiology of human breast cancer. Since then, many viruses have been associated with this disease (murine mammary tumor virus, MMTV; Epstein-Barr virus, EBV; and human papillomavirus, HPV). Recently, BLV has been identified in human breast cancers giving rise to the hypothesis that it could be one of the causative agents of this condition. BLV is a retrovirus distributed worldwide that affects cattle, causing lymphosarcoma in a small proportion of infected animals. Because of its similarity with human retroviruses like HTLV and HIV, BLV was assumed to also be involved in tumor emergence. Based on this assumption, studies were focused on the possible role of BLV in human breast cancer development. We present a compilation of the current knowledge on the subject and some prospective analysis that is required to fully end this controversy.

Association of Mouse Mammary Tumor Virus With Human Breast Cancer: Histology, Immunohistochemistry and Polymerase Chain Reaction Analyses.

The purpose of this study is to determine whether mouse mammary tumor virus (MMTV)-associated human breast cancer has the same or similar histology to MMTV-associated mouse mammary tumors. Such associations may indicate a role for MMTV in human breast cancer. Immunohistochemical techniques (using antibodies directed against the signal peptide p14 of the envelope precursor protein of MMTV) and polymerase chain reaction (PCR) analyses were used to identify MMTV proteins and MMTV-like envelope gene sequences in a series of breast cancers from Australian women. The histological characteristics of these human breast cancer specimens were compared with MMTV positive mouse mammary tumors. The same methods were used to study benign breast tissues which 1-11 years later developed into breast cancer. MMTV p14 proteins were identified in 27 (54%) of 50 human breast cancers. MMTV env gene sequences were identified by PCR in 12 (27%) of 45 human breast cancers. There was a significant correlation between the presence of MMTV (identified by p14 immunohistochemistry) in human breast cancers and histological characteristics similar to MMTV positive mouse mammary tumors (p = 0.001). There was a non-significant correlation between the presence of MMTV env gene sequences (identified by PCR) in human breast cancers and histological characteristics similar to MMTV positive mouse mammary tumors (p = 0.290). MMTV p14 proteins were identified in 7 (54%) of 13 benign breast specimens that later developed into human breast cancers. MMTV by PCR was identified in two benign specimens one of whom later developed MMTV positive breast cancer. These observations offer evidence that MMTV may be associated with characteristic human breast cancer histology. p14-based immunohistochemistry appears to be a more reliable technique than PCR for the identification of MMTV in human breast cancer. Identification of MMTV-associated p14 proteins in benign breast tissues confirms prior PCR-based studies that MMTV infection occurs before the development of MMTV positive breast cancer. Many MMTV positive human breast cancers have similar histology to MMTV positive mouse mammary tumors. MMTV infection identified in benign breast tissues precedes development of MMTV positive human breast cancer. When considered in the context of prior studies, these observations indicate a likely role for MMTV in human breast cancer.

Association of BCSC-1 and MMP-14 with human breast cancer.

Breast cancer suppressor candidate-1 (BCSC-1) is a candidate tumor suppressor gene that was identified recently. Decreased levels of BCSC-1 have been detected in a variety of cancer types in previous studies. Matrix metalloproteinase (MMP)-14 is a membrane-type MMP that plays an important role in tumor progression and prognosis. Previous research has indicated that MMP-14 is highly expressed in different cancer types and promotes tumor invasion or metastasis by remodeling the extracellular matrix. However, there have been few reports on BCSC-1 and MMP-14 in human breast cancer in recent years. In the present study, the association of BCSC-1 and MMP-14 with human breast cancer was investigated. The immunohistochemical analysis results revealed reduced expression of BCSC-1 and overexpression of MMP-14 in breast cancer tissues compared with adjacent normal breast tissues. Quantitative polymerase chain reaction and western blot analyses also showed that BCSC-1 was expressed at significantly lower levels, and that MMP-14 was expressed at significantly higher levels in breast cancer tissues compared with healthy breast tissue. Furthermore, decreased expression of BCSC-1 and overexpression of MMP-14 were associated with tumor cellular differentiation, lymph node metastasis and distant metastasis. A correlational analysis between BCSC-1 and MMP-14 was also conducted, and the results indicated a negative correlation between the two. In conclusion, the current findings indicate that BCSC-1 is downregulated, while MMP-14 is overexpressed in human breast cancer. These two genes may play important roles during the process of human breast cancer development.

Detection of human papillomavirus DNA in tumors from Rwandese breast cancer patients.

During the last decades, a great interest was given to viral etiology of breast cancer. Indeed, due to recent technical improvements and some encouraging new results, it has been a resurgence of interest in the possibility that a substantial proportion of human breast cancers may be caused by viral infections. High-risk genotypes of human papillomavirus (HPV) have been found in breast cancer cases. In the present study, we aimed to assess the presence of HPV DNA in breast cancer cases from Rwanda and to evaluate the association between HPV infection and clinico-pathological features. Therefore, a total of 47 archived formalin-fixed paraffin-embedded biopsies were collected and complete information was recorded. HPV detection and genotyping were done by PCR amplification and DNA sequencing. Overall, HPV DNA was found in 46.81% of cases, HPV16 being the most prevalent subtype (77.27%) followed by HPV33 (13.64%) and HPV31 (9.09%). Comparison of HPV with clinico-pathological features showed no significant difference between HPV infection and breast localization, histological subtype, clinical stage, tumor grade, and intrinsic molecular subtypes. These findings provide evidence of high prevalence of high-risk HPV in Rwandese patients with breast cancer and suggest that high-risk HPV infections could be a risk factor associated with human breast cancer development.

Cytotoxicity and cell migration suppression by noni fruit extract on michigan cancer Foundation-7 human breast cancer cells and development of topical microemulsions

Background: There is limited data about the anti-breast cancer activity of noni fruit ethanolic extract. Topical route is gaining interest as an alternative route for breast cancer treatment. Objectives: The aims of this study were to investigate the effect of noni fruit extract on cytotoxicity and cell migration suppression in Michigan Cancer Foundation-7 (MCF-7) human breast cancer cells and to develop topical microemulsions (MEs). Materials and Methods: The noni fruit ethanolic extract was prepared. Rutin content, a marker, in the extract was analyzed, and the antioxidant activity of the extract was determined. Cytotoxicity and cell migration suppression, indicating anti-breast cancer activity, were also assessed in MCF-7 cells by SRB assay and wound-healing assay. The MEs were developed by titration method. The developed noni MEs were evaluated regarding their physical appearance, viscosity, and pH before and after stability test. Results: Results showed that the rutin content in the noni extract was 4.02 ± 0.34 mg/g. The extract possessed antioxidant activity with inhibitory concentration (IC50) of 1.03 ± 0.01 mg/ml. It also showed cytotoxicity with IC50 values of 158.4 ± 12.5 μg/ml and cell migration suppression on MCF-7 cells with significant effect at 100 μg/ml. Eight ME systems were selected to incorporate the extract. Conclusion: Noni extract had potential anti-breast cancer activity. The ME, named noni ME-3, consisting of 0.7% w/w noni extract, 56% w/w olive oil, 20% w/w polysorbate 80, 20% w/w sorbitan oleate, and 4% w/w water phase, was shown to be the most attractive noni ME for the topical treatment of breast cancer. Abbreviations used: HPLC: High-performance liquid chromatography; SRB: Sulforhodamine B assay; RT: Room temperature.

Nicotinic Acetylcholine Receptor Subtype Alpha-9 Mediates Triple-Negative Breast Cancers Based on a Spontaneous Pulmonary Metastasis Mouse Model.

Triple-negative breast cancer (TNBC) subtype is associated with poor prognosis and a high risk of recurrence-related death in women. Despite the aggressiveness of TNBCs, targeted TNBC therapy is not yet available in the clinic. To overcome this challenge, we generated highly metastatic TNBC cells (LM) derived from metastasized lung cells via a serial spontaneous pulmonary metastasis animal model to identify targetable molecules for attenuating the progression of TNBC metastasis. Gene analysis of primary tumor (P), first-round (1LM) and second-round (2LM) metastasized lung cells revealed that mesenchymal-related genes were significantly expressed in LM cells, especially in 2LM cells. Interestingly, α9-nAChR gene expression was also dramatically induced in LM cells, confirming our previous finding that α9-nAChR plays important roles in receptor-mediated carcinogenic signals in human breast cancer development. Using α9-nAChR as a biomarker, we transfected 2LM cells with CRISPR/Cas9 lentivirus targeting the α9-nAChR genomic region (2LM-α9-nAChR-null), showing that mesenchymal markers and the migration and invasion abilities of 2LM cells were significantly attenuated in 2LM-α9-nAChR-null cells both in vitro and in vivo. In addition, the high efficiency of editing the α9-nAChR gene using a CRISPR/Cas9 lentivirus was demonstrated by gene sequencing, genomic indel frequency and protein expression analyses. Collectively, these results confirmed those of our previous study that advanced-stage breast tumors are associated with substantially higher levels of α9-nAChR gene expression, indicating that α9-nAChR expression is essential for mediating TNBC metastasis during cancer development and may potentially act as a biomarker for targeted therapy in clinical investigations.

PFOS induces proliferation, cell-cycle progression, and malignant phenotype in human breast epithelial cells

Perfluorooctanesulfonic acid (PFOS) is a synthetic fluorosurfactant widely used in the industry and a prominent environmental toxicant. PFOS is persistent, bioaccumulative, and toxic to mammalian species. Growing evidence suggests that PFOS has the potential to interfere with estrogen homeostasis, posing a risk of endocrine-disrupting effects. Recently, concerns about a potential link between PFOS and breast cancer have been raised, but the mechanisms underlying its actions as a potential carcinogen are unknown. By utilizing cell proliferation assays, flow cytometry, immunocytochemistry, and cell migration/invasion assays, we examined the potentially tumorigenic activity of PFOS (100 nM–1 mM) in MCF-10A breast cell line. The results showed that the growth of MCF-10A cells exposed to 1 and 10 µM PFOS was higher compared to that of the control. Mechanistic studies using 10 µM PFOS demonstrated that the compound promotes MCF-10A proliferation through accelerating G0/G1-to-S phase transition of the cell cycle after 24, 48, and 72 h of treatment. In addition, PFOS exposure increased CDK4 and decreased p27, p21, and p53 levels in the cells. Importantly, treatment with 10 µM PFOS for 72 h also stimulated MCF-10A cell migration and invasion, illustrating its capability to induce neoplastic transformation of human breast epithelial cells. Our experimental results suggest that exposure to low levels of PFOS might be a potential risk factor in human breast cancer initiation and development.

High prevalence of mouse mammary tumor virus-like gene sequences in breast cancer samples of Iranian women

ABSTRACTMouse mammary tumor virus (MMTV) is considered to be responsible for breast tumor development in mice. In several instances sequences homologous to the genome of this virus have been reported in human breast cancer samples.Here we aimed to evaluate MMTV involvement in human breast cancer development. DNA was extracted from 118 formalin fixed and paraffin embedded malignant (n = 59) and benign (n = 59) breast lesions. Using two sets of outer and inner MMTV-like envelope specific primers, in a nested PCR setup, MMTV genome was detected in 19 samples out of 59 (%32.2) cases of breast carcinomas, while in non-malignant breast tissue samples, only 3 samples out of 59 (%5) were positive. The difference was statistically highly significant (p < 0.001). Alignment of PCR amplified sequences with BR6, GR and C3H mouse mammary tumor virus strains emerged to be around 99% identical which is indicative of tumor tissue infection by an exogenous mouse MMTV genome.

Notch and its oncogenic activity in human malignancies.

SummaryBackgroundIncreasing evidence has demonstrated that Notch signaling is deregulated in human hematological malignancies and solid tumors. This signaling has a protumorigenic effect but may also act as a tumor suppressor. How induction of a single pathway gives rise to the opposite effects in different cell types is still unknown.MethodsThis review article includes available data from peer-reviewed publications associated with the role of Notch signaling during cancer pathogenesis.ResultsNumerous reports have indicated that alterations in Notch signaling and its oncogenic activity were originally associated with the pathogenesis of T‑cell acute lymphoblastic leukemia/lymphoma (T-ALL), an aggressive hematologic tumor affecting children and adolescents. The possibility that Notch could play a significant role in human breast cancer development comes from studies on mouse mammary tumor virus-induced cancer. Numerous findings over the past several years have indicated that alterations in Notch signaling are also responsible for ovarian cancer development. Mention should also be made of the connection between expression of Notch 3 and increased resistance to chemotherapy, which remains a major obstacle to successful treatment. Notch as an oncogenic factor is also involved in the development of colon cancer, lung carcinoma and Kaposi’s sarcoma.ConclusionNotch is a binary cell fate determinant and its overexpression has been described as oncogenic in a wide array of human malignancies. This finding led to interest in therapeutically targeting this pathway, especially by the use of gamma-secretase inhibitors (GSIs) blocking the cleavage of Notch receptors at the cell membrane by the inhibition of Notch intracellular domain (NICD) releasing. Preclinical cancer models have revealed that GSIs suppress the growth of cancers such as pancreatic, breast and lung cancer.

Ezrin-Radixin-Moesin Binding Phosphoprotein 50 (EBP50) Suppresses the Metastasis of Breast Cancer and HeLa Cells by Inhibiting Matrix Metalloproteinase-2 Activity.

Expression of ezrin-radixin-moesin-binding phosphoprotein-50 (EBP50) is correlated with human breast and cervical cancer development, but its effects on the metastasis of breast and cervical cancer and the underlying mechanism are not fully understood. In this study, EBP50 was overexpressed in MDA-MB-231 breast cancer and HeLa cervical cancer cells; moreover, EBP50 was knocked-down in MCF-7 breast cancer cells and HeLa cells. Metastasis-related ability and matrix metalloproteinase-2 (MMP-2) activity of these cells were investigated. Cell adhesion, wound-healing and invasion were significantly suppressed in EBP50-overexpressing cells. Contrarily, EBP50-knockdown promoted cell adhesion, wound healing and invasion. EBP50 overexpression inhibited MMP-2 activity, and the knockdown of EBP50 promoted the activity of MMP-2, suggesting that EBP50 inhibited cell metastasis via suppression of MMP-2 activity. Our work reveals the anti-metastatic effect and a new mechanism of EBP50 action in breast and cervical cancer cells.

Down-regulation of the Tumor Suppressor CYLD Enhances the Transformed Phenotype of Human Breast Cancer Cells.

The cylindromatosis tumor suppressor (CYLD) has been implicated in the inhibition of human breast cancer development by virtue of the poor prognosis of patients with down-regulated CYLD expression. In order to investigate the mechanism of breast cancer suppression by CYLD, in the present study, cellular and molecular aspects of CYLD-dependent phenotypic regulation of different types of human breast cancer cell lines were analyzed. CYLD expression was down-regulated by RNA interference in human breast cancer cell lines. Parental and CYLD-deficient cell lines were evaluated for their viability, migratory capacity, anchorage-independent growth and chemoresistance. Wild-type and mutated forms of CYLD were also evaluated for their ability to suppress the clonogenic potential of breast cancer cells. CYLD down-regulation enhanced the survival and migratory properties of basal and luminal breast cancer cell lines. In addition, down-regulation of CYLD expression enhanced the ability of human breast cancer cells to grow in an anchorage-independent manner and could be associated with resistance to chemotherapeutic drugs. The growth-suppressive properties of CYLD on breast cancer cell lines were dependent on its de-ubiquitinating activity and its amino terminal cytoskeleton-interacting region. Our results establish a broad range of tumor-suppressive properties that are conferred by CYLD in basal and luminal human breast cancer cells and support the significance of targeted de-ubiquitination by CYLD in breast cancer cell growth suppression.

Abstract 1839: TGFBR1*6A mouse model mimics human breast cancer development and progression

Abstract Transforming Growth Factor-ß (TGF-β) is one of the most commonly altered cellular signaling pathways in human cancer. Our group was the first to discover TGFBR1*6A (*6A), a common hypomorphic variant of the type I TGF-ß receptor (TGFBR1), which has been associated with increased risk for breast cancer in multiple epidemiological studies. Functional analysis also suggests that *6A is associated with decreased tumor suppressive TGF-β signaling in early tumor development and is involved with promoting tumorigenesis in advanced carcinomas. To better understand the functional impact of *6A and constitutively reduced TGF-ß signaling on breast cancer development and progression, we have recently developed a series of transgenic knock-in mouse model variants by replacing exon 1 of the mouse Tgfbr1 sequence with human exon 1 sequences harboring both *6A and wild-type (*9A) TGFBR1 variants and crossed them with MMTVneu mice. We generated a total of 5 FVB double and/or triple transgenic mouse strains: MMTVneu;9A/9A, MMTVneu;6A/6A, MMTVneu;9A/6A, MMTVneu;*9A/-, and MMTVneu;6A/-. Following tumor development, measurements were performed three times per week to determine tumor volume. All mice were allowed to live up to 18 months (548 days) or until they died of natural causes. Specimens were collected for later analysis of blood, tumors, normal mammary tissue, and were evaluated for lung metastases. Statistical comparisons performed using Student’s t-test. Only 34.4% of MMTVneu;9A/9A mice (11/32) developed mammary tumors, while 80% of MMTVneu;6A/6A mice (24/30; p=0.0002) and 62.5% of MMTVneu;6A/- mice (19/32, p=0.046) developed tumors. The percentage of MMTVneu;9A/6A and MMTVneu;*9A/- mice that developed tumors was higher than MMTVneu;9A/9A mice (48.3% and 50%, respectively) but was not statistically significant. Additionally, 66.7% of MMTVneu;6A/6A mice (20/30) developed 2 or more tumors, while only 25% of MMTVneu;9A/9A mice (8/32) developed multiple tumors (p=0.0007). Our data suggests that we have developed transgenic mouse strains that accurately mimic human breast cancer susceptibility associated with *6A and constitutively decreased TGFBR1 expression in humans, as evidenced by other studies. These mouse models may be a tool to provide invaluable insight to better understand the role of TGFBR1 variants in the development and progression of breast cancer. Citation Format: Michael James Pennison, Minghui Wang, Hugo Jimenez, Boris Pasche. TGFBR1*6A mouse model mimics human breast cancer development and progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1839. doi:10.1158/1538-7445.AM2017-1839

Acyl-CoA thioesterase 7 is involved in cell cycle progression via regulation of PKC\u03b6\u2013p53\u2013p21 signaling pathway

Acyl-CoA thioesterase 7 (ACOT7) is a major isoform of the ACOT family that catalyzes hydrolysis of fatty acyl-CoAs to free fatty acids and CoA-SH. However, canonical and non-canonical functions of ACOT7 remain to be discovered. In this study, for the first time, ACOT7 was shown to be responsive to genotoxic stresses such as ionizing radiation (IR) and the anti-cancer drug doxorubicin in time- and dose-dependent manners. ACOT7 knockdown induced cytostasis via activation of the p53–p21 signaling pathway without a DNA damage response. PKCζ was specifically involved in ACOT7 depletion-mediated cell cycle arrest as an upstream molecule of the p53–p21 signaling pathway in MCF7 human breast carcinoma and A549 human lung carcinoma cells. Of the other members of the ACOT family, including ACOT1, 4, 8, 9, 11, 12, and 13 that were expressed in human, ACOT4, 8, and 12 were responsive to genotoxic stresses. However, none of those had a role in cytostasis via activation of the PKCζ–p53–p21 signaling pathway. Analysis of the ACOT7 prognostic value revealed that low ACOT7 levels prolonged overall survival periods in breast and lung cancer patients. Furthermore, ACOT7 mRNA levels were higher in lung cancer patient tissues compared to normal tissues. We also observed a synergistic effect of ACOT7 depletion in combination with either IR or doxorubicin on cell proliferation in breast and lung cancer cells. Together, our data suggest that a low level of ACOT7 may be involved, at least in part, in the prevention of human breast and lung cancer development via regulation of cell cycle progression.

Molecular Signaling of Progesterone, Growth Hormone, Wnt, and HER in Mammary Glands of Dogs, Rodents, and Humans: New Treatment Target Identification.

Mammary tumors are the most common form of neoplasia in the bitch. Female dogs are protected when they are spayed before the first estrus cycle, but this effect readily disappears and is already absent when dogs are spayed after the second heat. As the ovaries are removed during spaying, ovarian steroids are assumed to play an essential role in tumor development. The sensitivity toward tumor development is already present during early life, which may be caused by early mutations in stem cells during the first estrus cycles. Later on in life, tumors arise that are mostly steroid-receptor positive, although a small subset of tumors overexpressing human epidermal growth factor 2 (HER2) and some lacking estrogen receptor, progesterone receptor (PR), and HER2 (triple negative) are present, as is the situation in humans. Progesterone (P4), acting through PR, is the major steroid involved in outgrowth of mammary tissue. PRs are expressed in two forms, the progesterone receptor A (PRA) and progesterone receptor B (PRB) isoforms derived from splice variants from a single gene. The dog and the whole family of canids have only a functional PRA isoform, whereas the PRB isoform, if expressed at all, is devoid of intrinsic biological activity. In human breast cancer, overexpression of the PRA isoform is related to more aggressive carcinomas making the dog a unique model to study PRA-related mammary cancer. Administration of P4 to adult dogs results in local mammary expression of growth hormone (GH) and wing less-type mouse mammary tumor virus integration site family 4 (Wnt4). Both proteins play a role in activation of mammary stem cells. In this review, we summarize what is known on P4, GH, and Wnt signaling in canine mammary cancer, how the family of HER receptors could interact with this signaling, and what this means for comparative and translational oncological aspects of human breast cancer development.

Identification of NEK3 Kinase Threonine 165 as a Novel Regulatory Phosphorylation Site That Modulates Focal Adhesion Remodeling Necessary for Breast Cancer Cell Migration

Accumulating evidence supports a role for prolactin (PRL) in the development and progression of human breast cancer. Although PRL is an established chemoattractant for breast cancer cells, the precise molecular mechanisms of how PRL regulates breast cancer cell motility and invasion are not fully understood. PRL activates the serine/threonine kinase NEK3, which was reported to enhance breast cancer cell migration, invasion, and the actin cytoskeletal reorganization necessary for these processes. However, the specific mechanisms of NEK3 activation in response to PRL signaling have not been defined. In this report, a novel PRL-inducible regulatory phosphorylation site within the activation segment of NEK3, threonine 165 (Thr-165), was identified. Phosphorylation at NEK3 Thr-165 was found to be dependent on activation of the extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathway using both pharmacological inhibition and siRNA-mediated knockdown approaches. Strikingly, inhibition of phosphorylation at NEK3 Thr-165 by expression of a phospho-deficient mutant (NEK3-T165V) resulted in increased focal adhesion size, formation of zyxin-positive focal adhesions, and reorganization of the actin cytoskeleton into stress fibers. Concordantly, NEK3-T165V cells exhibited migratory defects. Together, these data support a modulatory role for phosphorylation at NEK3 Thr-165 in focal adhesion maturation and/or turnover to promote breast cancer cell migration.

MKNK2 is a valid target of miR-125b in breast cancer

MAP kinase interacting serine/threonine kinase 2 (MKNK2) belongs to the protein kinase superfamily which phosphorylates and activates eukaryotic initiation factor 4E (elF4E), a rate limiting factor in protein synthesis that enhances the translation of some proteins involved in cell cycle, apoptosis and angiogenesis regulation. In this study, we found that the expression levels of MKNK2 are inversely correlated with the expression levels of miR-125b in human breast cancer development. We showed that miR-125b inhibited tumor cell growth and invasion by regulating MKNK2 at posttranscriptional level. Thus, both miR-125b and MKNK2 could be therapeutically targeted in breast cancer.

Upregulation and activation of δ‑opioid receptors promotes the progression of human breast cancer.

δ‑opioid receptor(DOR) belongs to the family of Gprotein‑coupled receptors(GPCRs). Numerous studies have shown that DOR is widely distributed in human peripheral tissues and is closely related to the development and progression of certain malignant tumours. However, there is controversy in the literature regarding whether DOR has an impact on the development and progression of human breast cancer. The present study comprehensively elaborates on the biological functions of DOR by determining the distribution of DOR expression in breast cancer tissues and cells and by further verifying the effects of DOR on breast cancer progression. DOR was found to be highly expressed in human breast cancer tissues and cells. In addition, the high expression level of DOR positively correlated with tumour grade and clinical stage and negatively correlated with breast cancer metastasis and prognosis. Upregulating and activating DOR promoted the proliferation of human breast cancer cells in a concentration‑dependent manner within a specific concentration range, whereas downregulating or inhibiting DOR activation significantly suppressed cell proliferation. The majority of tumour cells were arrested in G1 phase, and some cells exhibited apoptosis. DOR upregulation and activation induced protein kinaseC(PKC) activation, resulting in increased phosphorylation levels of extracellular signal‑regulated kinases(ERKs). After inhibition of the PKC/ERK signalling pathway, the effects of DOR on breast cancer were significantly attenuatedinvivo andinvitro. In summary, DOR is highly expressed in breast cancer and is closely related to its progression. These results suggest that DOR may serve as a potential biomarker for the early diagnosis of breast cancer and may be a viable molecular target for therapeutic intervention.

Dual roles of CCN proteins in breast cancer progression.

The tumor microenvironment has a powerful effect on the development and progression of human breast cancer, which may be used therapeutically. Despite efforts to understand the complex role of the tumor microenvironment in breast cancer development, the specific players and their contributions to tumorigenesis need further investigation. The CCN family of matricellular proteins comprises six members (CCN1-6; CYR61, CTGF, NOV, WISP1-3) with central roles in development, inflammation, and tissue repair. CCN proteins also exert functions during pathological processes including fibrosis and cancer by regulating extracellular signals in the cellular environment. Studies have demonstrated that all six CCN proteins exert functions in breast tumorigenesis. Although CCN proteins share a multimodular structure in which most cysteine residues are conserved within structural motifs, they may have opposing functions in breast cancer progression. A better understanding of the functions of each CCN member will assist in the development of specific therapeutic approaches for breast cancer.

Abstract 820: Molecular epidemiological studies of germinal center-associated nuclear protein (ganp) in the development of human sporadic breast cancers

Abstract [Introduction] The altered expression of germinal center-associated nuclear protein (GANP), a member of mammalian TREX2 complex, has been observed in various tumors. Previously, we demonstrated that deficiency of GANP developed mammary gland tumors resembling human breast cancers in two mouse models. In addition, we showed that decreased expression of GANP was an independent prognostic factor of human breast cancer in a retrospective cohort study. These results suggested that GANP might be associated with breast cancer development. Although a little is know about functional significance of ganp polymorphisms, we explored possible association. [Methods] We conducted a case-control study to examine association between ganp polymorphisms and risk of breast cancer among Japanese population within the framework of the Hospital-based Epidemiologic Research Program at Aichi Cancer Center (HERPACC). Cases are 694 incident cases who had been diagnosed as breast cancer at Aichi Cancer Center Hospital (ACCH) during 2001-2005. A total of 1,376 non-cancer controls were patients who visited ACCH at same period as cases and were confirmed to have no evidence of cancer. Controls were individually matched for age and menopausal status with cases. ganp polymorphisms were assessed by iCOGS chip (Reference: Michailidou K et al. Nat. Genet. 2013;45:353-361). Multivariable conditional logistic regression models were applied to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for each locus. [Results] Ten out of 13 polymorphisms, in high linkage disequilibrium, showed statistically significant associations with breast cancer risk. For instance, in rs2839186, the OR for those with AA alleles compared with those with GG alleles is 0.41 (95% CI, 0.23-0.72, p = 0.002) in genotype model. As compared with those with G allele, the OR for those without was 0.40 (95% CI, 0.23-0.71, p = 0.002) in recessive model. On the other hand, in dominant model, the OR for those with A allele was 0.95 (95% CI, 0.78-1.16, p = 0.635) in comparison to those without that. [Conclusion] In this study, we clearly show that mutant SNPs in rs2839186 decrease breast cancer risk. We are currently analyzing if the ganp SNPs affect the prognosis of breast cancer patients. Citation Format: Kazuhiko Kuwahara, Hidemi Ito, Kiyotaka Kuzushima, Hiroji Iwata, Hideo Tanaka, Keitaro Matsuo. Molecular epidemiological studies of germinal center-associated nuclear protein (ganp) in the development of human sporadic breast cancers. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 820.

Abstract P4-04-08: Presence of tumor-specific cytolytic T cells in human primary breast carcinoma: Consequences for immunotherapy

Abstract Background: Immunotherapy through stimulatory antibodies targeting the CTLA-4 or PD-1 pathways has a clear clinical efficacy in a fraction of patients with various cancers. It is likely that the main immune effectors of these therapies are CD8+ cytolytic T lymphocytes (CTL) recognizing tumor-specific antigens. The antigenicity of human tumors has been demonstrated with studies conducted mostly on melanomas. However the genetic mechanisms leading to antigenicity, notably point mutations in the tumor cells, apply to all cancer types. Thus primary breast carcinoma cells do certainly bear tumor-specific antigens, even though the extent of this antigenicity is unknown. Most melanomas, which are highly antigenic tumors, are also immunogenic, i.e. they stimulate spontaneous anti-tumor CTL responses. This immunogenicity, of which the presence of tumor-infiltrating T cells (TILs) is probably a surrogate marker, might be a predictive marker for clinical benefit to immunostimulatory antibodies. Whether primary breast carcinomas are immunogenic is not known, mainly due the absence of autologous tumor cell lines to analyze patients' T cells. However even in the absence of T-cell aimed immunotherapy the amounts of TILs have been positively correlated with patients' survival. Here we wished to obtain evidence for the presence of tumor-specific CD8+ T cells in TILs from primary breast carcinomas. Methods: From each tumor we isolated TILs and derived a random set of ±100 CD8+ clones maintained in culture by stimulation with anti-CD3 antibodies, thus irrespective of their antigenic specificity. We screened these clones for recognition of tumor-specific antigens present on the autologous tumor. In the absence of autologous tumor lines we restricted our analysis to mutated antigens selected on the basis of tumor exome sequencing and gene expression profiling. Indels and non-synonymous base substitutions were selected to synthesize candidate mutated peptides. Results: Thus far we have analyzed two hormone receptor-positive HER2-negative primary carcinomas. For one patient we screened 144 T cell clones for recognition of 40 candidate mutated peptides, without any positive result. For the other patient, 6 out of 98 T cell clones recognized 4 out of 119 candidate mutated peptides. Two peptides were recognized by two different T cell clones, i.e. with different T cell receptor sequences. These 4 'antigenic' mutations appear to be passenger, i.e. the four genes have a low published mutation frequency. Conclusions: We conclude that some human primary breast carcinomas are immunogenic, as one tumor contained at least 6% of tumor-specific T cells among the CD8+ TILs. It suggests that the corresponding patient could benefit from the currently used immunostimulatory antibodies. More work is required to understand the reasons for the negative results in the first patient. We are pursuing the work on 2 HER2-positive and 2 triple-negative tumors, in which TILs are better correlated with prognosis. Our results warrant more investigations on the activation or inhibition of tumor-specific T cells at early stages of human breast cancer development. Citation Format: Schröder DJ, Bricard O, Hames G, Remy N, Carrasco J, Canon J-L, Berlière M, Galant C, Coulie PG. Presence of tumor-specific cytolytic T cells in human primary breast carcinoma: Consequences for immunotherapy. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-04-08.