Free drug and ROS-responsive nanoparticle delivery of synergistic doxorubicin and olaparib combinations to triple negative breast cancer models

Combinations of the topoisomerase II inhibitor doxorubicin and the poly (ADP-ribose) polymerase inhibitor olaparib offer potential drug-drug synergy for the treatment of triple negative breast cancers (TNBC). In this study we performed in vitro screening of combinations of these drugs, administered directly or encapsulated within polymer nanoparticles, in both 2D and in 3D spheroid models of breast cancer. A variety of assays were used to evaluate drug potency, and calculations of combination index (CI) values indicated that synergistic effects of drug combinations occurred in a molar-ratio dependent manner. It is suggested that the mechanisms of synergy were related to enhancement of DNA damage as shown by the level of double-strand DNA breaks, and mechanisms of antagonism associated with mitochondrial mediated cell survival, as indicated by reactive oxygen species (ROS) generation. Enhanced drug delivery and potency was observed with nanoparticle formulations, with a greater extent of doxorubicin localised to cell nuclei as evidenced by microscopy, and higher cytotoxicity at the same time points compared to free drugs. Together, the work presented identifies specific combinations of doxorubicin and olaparib which were most effective in a panel of TNBC cell lines, explores the mechanisms by which these combined agents might act, and shows that formulation of these drug combinations into polymeric nanoparticles at specific ratios conserves synergistic action and enhanced potency in vitro compared to the free drugs.

Unravelling transcriptomic complexity in breast cancer through modulation of DARPP-32 expression and signalling pathways

DARPP-32 is a key regulator of protein-phosphatase-1 (PP-1) and protein kinase A (PKA), with its function dependent upon its phosphorylation state. We previously identified DKK1 and GRB7 as genes with linked expression using Artificial Neural Network (ANN) analysis; here, we determine protein expression in a large cohort of early-stage breast cancer patients. Low levels of DARPP-32 Threonine-34 phosphorylation and DKK1 expression were significantly associated with poor patient prognosis, while low levels of GRB7 expression were linked to better survival outcomes. To gain insight into mechanisms underlying these associations, we analysed the transcriptome of T47D breast cancer cells following DARPP-32 knockdown. We identified 202 differentially expressed transcripts and observed that some overlapped with genes implicated in the ANN analysis, including PTK7, TRAF5, and KLK6, amongst others. Furthermore, we found that treatment of DARPP-32 knockdown cells with 17β-estradiol or PKA inhibitor fragment (6-22) amide led to the differential expression of 193 and 181 transcripts respectively. These results underscore the importance of DARPP-32, a central molecular switch, and its downstream targets, DKK1 and GRB7 in breast cancer. The discovery of common genes identified by a combined patient/cell line transcriptomic approach provides insights into the molecular mechanisms underlying differential breast cancer prognosis and highlights potential targets for therapeutic intervention.

High BMP7 expression is associated with poor prognosis in ovarian cancer

Bone Morphogenetic Protein 7 (BMP7) is an extracellular signalling protein that belongs to the transforming growth factor-β (TGF- β) superfamily. Previous transcriptomic data suggested that BMP7 expression may be disrupted in ovarian carcinoma and may play an important role in the aggressiveness of the disease. However, the protein expression in patient tumours has not been well studied. The current study aimed to assess BMP7 protein expression in a large cohort of ovarian carcinoma patient tumour samples to establish its associations with different clinical endpoints. Ovarian carcinoma tissue samples from 575 patients who underwent surgery for different subtypes of ovarian cancer were used. BMP7 protein expression was analysed by immunohistochemistry using tissue microarray and full face tumour sections. High BMP7 expression is associated with aggressive ovarian cancer clinicopathological variables including advanced FIGO stage, high grade, residual disease and poor overall survival. Elevated cytoplasmic and nuclear BMP7 expression was significantly associated with advanced FIGO stage, high tumour grade, presence of residual tumours and high-grade serous carcinomas (p = 0.001, 0.005, 0.004, <0.001 and p < 0.001, <0.001, 0.002, 0.001 respectively). Increased cytoplasmic and nuclear BMP7 expression was also significantly associated with an adverse overall survival (p = 0.001 and 0.046 respectively). The study highlights the potential of BMP7 as a prognostic tool and as a potential novel target for ovarian cancer therapies to limit disease progression.

p53 and ovarian carcinoma survival: an Ovarian Tumor Tissue Analysis consortium study

Our objective was to test whether p53 expression status is associated with survival for women diagnosed with the most common ovarian carcinoma histotypes (high-grade serous carcinoma [HGSC], endometrioid carcinoma [EC], and clear cell carcinoma [CCC]) using a large multi-institutional cohort from the Ovarian Tumor Tissue Analysis (OTTA) consortium. p53 expression was assessed on 6,678 cases represented on tissue microarrays from 25 participating OTTA study sites using a previously validated immunohistochemical (IHC) assay as a surrogate for the presence and functional effect of TP53 mutations. Three abnormal expression patterns (overexpression, complete absence, and cytoplasmic) and the normal (wild type) pattern were recorded. Survival analyses were performed by histotype. The frequency of abnormal p53 expression was 93.4% (4,630/4,957) in HGSC compared to 11.9% (116/973) in EC and 11.5% (86/748) in CCC. In HGSC, there were no differences in overall survival across the abnormal p53 expression patterns. However, in EC and CCC, abnormal p53 expression was associated with an increased risk of death for women diagnosed with EC in multivariate analysis compared to normal p53 as the reference (hazard ratio [HR] = 2.18, 95% confidence interval [CI] 1.36-3.47, p = 0.0011) and with CCC (HR = 1.57, 95% CI 1.11-2.22, p = 0.012). Abnormal p53 was also associated with shorter overall survival in The International Federation of Gynecology and Obstetrics stage I/II EC and CCC. Our study provides further evidence that functional groups of TP53 mutations assessed by abnormal surrogate p53 IHC patterns are not associated with survival in HGSC. In contrast, we validate that abnormal p53 IHC is a strong independent prognostic marker for EC and demonstrate for the first time an independent prognostic association of abnormal p53 IHC with overall survival in patients with CCC.

A retrospective analysis of ezrin protein and mRNA expression in breast cancer: Ezrin expression is associated with patient survival and survival of patients with receptor-positive disease

INTRODUCTION

The cytoskeletal protein ezrin is upregulated in many cancer types and is strongly associated with poor patient outcome. While the clinical and prognostic value of ezrin has been previously evaluated in breast cancer, most studies to date have been conducted in smaller cohorts (less than 500 cases) or have focused on specific disease characteristics. The current study is the largest of its kind to evaluate ezrin both at the protein and mRNA levels in early-stage breast cancer patients using the Nottingham (n = 1094) and METABRIC (n = 1980) cohorts, respectively.

RESULTS

High expression of ezrin was significantly associated with larger tumour size (p = 0.027), higher tumour grade (p < 0.001), worse Nottingham Prognostic Index prognostic group (p = 0.011) and HER2-positive status (p = 0.001). High ezrin expression was significantly associated with adverse survival of breast cancer patients (p < 0.001) and remained associated with survival in multivariate Cox-regression analysis (p = 0.018, hazard ratio (HR) = 1.343, 95% confidence interval (CI) = 1.051-1.716) when potentially confounding factors were included. High ezrin expression was significantly associated with adverse survival of patients whose tumours were categorised as receptor (oestrogen receptor (ER), progesterone receptor (PgR) or HER2) positive (p < 0.001) in comparison to those categorised as triple-negative breast cancer (p = 0.889). High expression of ezrin mRNA (VIL2) in the METABRIC cohort was also significantly associated with adverse survival of breast cancer patients (p < 0.001).

CONCLUSION

Retrospective analyses show that ezrin is an independent prognostic marker, with higher expression associated with shortened survival in receptor-positive (ER, PgR or HER2) patients. Ezrin expression is associated with more aggressive disease and may have clinical utility as a biomarker of patient prognosis in early-stage breast cancer.

CYP2S1 and CYP2W1 expression is associated with patient survival in breast cancer

The cytochrome P450 family of enzymes metabolise a wide range of compounds and play important roles in breast cancer pathogenesis due to their involvement in estrogen metabolism and the production of carcinogenic metabolites during this process. The orphan CYPs, CYP2S1, and CYP2W1 are reportedly upregulated in breast cancer. However, their expression and association with clinicopathological and survival parameters have not been previously assessed in a large cohort of breast cancers. Protein expression of CYP2S1 and CYP2W1 was assessed in early-stage invasive breast cancers (n = 1,426) using immunohistochemistry and correlated with various clinicopathological parameters and survival. mRNA expression of CYP2S1 and CYP2W1 was also assessed in the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) cohort. Low nuclear and cytoplasmic CYP2S1 was significantly associated with high-grade tumours (p ≤ 0.009), intermediate Nottingham prognostic index (NPI) group (p ≤ 0.025), high mitotic frequency (p ≤ 0.002), human epidermal growth factor receptor 2 (HER2)-negative disease (p ≤ 0.011), and ductal carcinoma (p ≤ 0.022). Cytoplasmic CYP2S1 was additionally associated with patients ≥50 years (p < 0.001), estrogen receptor (ER)-positive tumours (p = 0.011), and high nuclear pleomorphism (p = 0.003). Low cytoplasmic CYP2W1 was significantly associated with patients ≥50 years (p = 0.002), HER2-negative disease (p = 0.003), intermediate NPI (p = 0.013), and mitosis (p = 0.009). Low cytoplasmic CYP2S1 was significantly associated with adverse breast cancer specific survival (p = 0.034), which remained so in multivariate analysis (hazard ratio [HR]: 0.639; 95% confidence interval [CI]: 0.483-0.846; p = 0.002). Low nuclear CYP2W1 was significantly associated with adverse breast cancer specific survival (p = 0.012), with significance also maintained in multivariate analysis (HR: 0.677; 95% CI: 0.510-0.898; p = 0.007). No associations with survival were observed in the METABRIC cohort. CYP2S1 and CYP2W1 are associated with patient survival in breast cancer and may be important prognostic biomarkers.

In vitro radiosensitization of breast cancer with hypoxia-activated prodrugs

KP167 is a novel hypoxia‐activated prodrug (HAP), targeting cancer cells via DNA intercalating and alkylating properties. The single agent and radiosensitizing efficacy of KP167 and its parental comparator, AQ4N, were evaluated in 2D and 3D cultures of luminal and triple negative breast cancer (TNBC) cell lines and compared against DNA damage repair inhibitors. 2D normoxic treatment with the DNA repair inhibitors, Olaparib or KU‐55933 caused, as expected, substantial radiosensitization (sensitiser enhancement ratio, SER_0.01 of 1.60–3.42). KP167 induced greater radiosensitization in TNBC (SER_0.01 2.53 in MDAMB‐231, 2.28 in MDAMB‐468, 4.55 in MDAMB‐436) and luminal spheroids (SER_0.01 1.46 in MCF‐7 and 1.76 in T47D cells) compared with AQ4N. Significant radiosensitization was also obtained using KP167 and AQ4N in 2D normoxia. Although hypoxia induced radioresistance, radiosensitization by KP167 was still greater under 2D hypoxia, yielding SER_0.01 of 1.56–2.37 compared with AQ4N SER_0.01 of 1.13–1.94. Such data show KP167 as a promising single agent and potent radiosensitiser of both normoxic and hypoxic breast cancer cells, with greater efficacy in TNBCs.

Cytotoxic and Radiosensitising Effects of a Novel Thioredoxin Reductase Inhibitor in Brain Cancers

The thioredoxin (Trx) system, a key antioxidant pathway, represents an attractive target for cancer therapy. This study investigated the chemotherapeutic and radiosensitising effects of a novel Trx reductase (TrxR) inhibitor, IQ10, on brain cancer cells and the underlying mechanisms of action. Five brain cancer cell lines and a normal cell type were used. TrxR activity and expression were assessed by insulin reduction assay and Western blotting, respectively. IQ10 cytotoxicity was evaluated using growth curve, resazurin reduction and clonogenic assays. Radiosensitivity was examined using clonogenic assay. Reactive oxygen species levels were examined by flow cytometry and DNA damage assessed by immunofluorescence. Epithelial-mesenchymal transition (EMT)-related gene expression was examined by RT-PCR array. IQ10 significantly inhibited TrxR activity but did not affect Trx system protein expression in brain cancer cells. The drug exhibited potent anti-proliferative and cytotoxic effects against brain cancer cells under both normoxic and hypoxic conditions in both 2D and 3D systems, with IC₅₀s in the low micromolar range. It was up to ~ 1000-fold more potent than temozolomide. IQ10 substantially sensitised various brain cancer cells to radiation, with such effect being due, in part, to functional inhibition of TrxR, making cells less able to deal with oxidative stress and leading to increased oxidative DNA damage. IQ10 significantly downregulated EMT-associated gene expression suggesting potential anti-invasive and antimetastatic properties. This study suggests that IQ10 is a potent anticancer agent and could be used as either a single agent or combined with radiation, to treat brain cancers.

Quantifying Lymphatic Vessel Density in Human Tissue Samples

The development of new blood and lymphatic vessels, through the process of angiogenesis and lymphangiogenesis, respectively, is critical to the development and growth of tumors, and integral to the process of metastasis. Lymphatic vessel density can be assessed as a surrogate measure of lymphangiogenesis in human tissue samples. Lymphatic vessel density has been shown to be associated with lymph node metastasis and patient survival in various solid tumor types. Here we describe a method for quantifying the number of lymphatic vessels within tumor tissue that can also be used to assess lymphatic vessel invasion, and compare with blood vessel density and invasion.

PP1, PKA and DARPP-32 in breast cancer: A retrospective assessment of protein and mRNA expression

Cyclic AMP–dependent protein kinase A (PKA) and protein phosphatase 1 (PP1) are proteins involved in numerous essential signalling pathways that modulate physiological and pathological functions. Both PP1 and PKA can be inhibited by dopamine‐ and cAMP‐regulated phosphoprotein 32 kD (DARPP‐32). Using immunohistochemistry, PKA and PP1 expression was determined in a large primary breast tumour cohort to evaluate associations between clinical outcome and clinicopathological criteria (n > 1100). In addition, mRNA expression of PKA and PP1 subunits was assessed in the METABRIC data set (n = 1980). Low protein expression of PKA was significantly associated with adverse survival of breast cancer patients; interestingly, this relationship was stronger in ER‐positive breast cancer patients. PP1 protein expression was not associated with patient survival. PKA and PP1 subunit mRNA was also assessed; PPP1CA, PRKACG and PRKAR1B were associated with breast cancer–specific survival. In patients with high expression of DARPP‐32, low expression of PP1 was associated with adverse survival when compared to high expression in the same group. PKA expression and PP1 expression are of significant interest in cancer as they are involved in a wide array of cellular processes, and these data indicate PKA and PP1 may play an important role in patient outcome.

Cytotoxic and radiosensitising effects of a novel thioredoxin reductase inhibitor in breast cancer

Radiotherapy is an effective treatment modality for breast cancer but, unfortunately, not all patients respond fully with a significant number experiencing local recurrences. Overexpression of thioredoxin and thioredoxin reductase has been reported to cause multidrug and radiation resistance - their inhibition may therefore improve therapeutic efficacy. Novel indolequinone compounds have been shown, in pancreatic cancer models, to inhibit thioredoxin reductase activity and exhibit potent anticancer activity. The present study evaluates, using in vitro breast cancer models, the efficacy of a novel indolequinone compound (IQ9) as a single agent and in combination with ionising radiation using a variety of endpoint assays including cell proliferation, clonogenic survival, enzyme activity, and western blotting. Three triple-negative breast cancer (MDA-MB-231, MDA-MB-468, and MDA-MB-436) and two luminal (MCF-7 and T47D) breast cancer cell lines were used. Results show that treatment with IQ9 significantly inhibited thioredoxin reductase activity, and inhibited cell growth and colony formation of breast cancer cells with IC₅₀ values in the low micromolar ranges. Enhanced radiosensitivity of triple-negative breast cancer cells was observed, with sensitiser enhancement ratios of 1.20–1.43, but with no evident radiosensitisation of luminal breast cancer cell lines. IQ9 upregulated protein expression of thioredoxin reductase in luminal but not in triple-negative breast cancer cells which may explain the observed differential radiosensitisation. This study provides important evidence of the roles of the thioredoxin system as an exploitable radiobiological target in breast cancer cells and highlights the potential therapeutic value of indolequinones as radiosensitisers.

***This study was not part of a clinical trial. Clinical trial registration number: N/A

Dopamine and cAMP-regulated phosphoprotein 32kDa (DARPP-32), protein phosphatase-1 and cyclin-dependent kinase 5 expression in ovarian cancer

Dopamine and cyclic‐AMP activated phosphoprotein Mr32kDa (DARPP‐32) is a central signalling protein in neurotransmission. Following DARPP‐32 phosphorylation by protein kinase A (PKA), DARPP‐32 becomes a potent protein phosphatase 1 (PP1) inhibitor. DARPP‐32 can itself inhibit PKA following DARPP‐32 phosphorylation by cyclin‐dependent kinase 5 (Cdk5). Increasing evidence indicates a role for DARPP‐32 and its associated signalling pathways in cancer; however, its role in ovarian cancer remains unclear. Using immunohistochemistry, expression of DARPP‐32, PP1 and Cdk5 was determined in a large cohort of primary tumours from ovarian cancer patients (n = 428, 445 and 434 respectively) to evaluate associations between clinical outcome and clinicopathological criteria. Low cytoplasmic and nuclear DARPP‐32 expression was associated with shorter patient overall survival and progression‐free survival (P = .001, .001, .004 and .037 respectively). Low nuclear and cytoplasmic DARPP‐32 expression remained significantly associated with overall survival in multivariate Cox regression (P = .045, hazard ratio (HR) = 0.734, 95% confidence interval (CI) = 0.542‐0.993 and P = .001, HR = 0.494, 95% CI = 0.325‐0.749, respectively). High cytoplasmic and nuclear PP1 expression was associated with shorter patient overall survival and high cytoplasmic PP1 expression with shorter progression‐free survival (P = .005, .033, and .037, respectively). High Cdk5 expression was associated with shorter progression‐free survival (P = .006). These data suggest a role for DARPP‐32 and associated signalling kinases as prognostic markers with clinical utility in ovarian cancer.

Thioredoxin System Protein Expression Is Associated with Poor Clinical Outcome in Adult and Paediatric Gliomas and Medulloblastomas

The thioredoxin (Trx) system is an important enzyme family that regulates cellular redox homeostasis. Protein expression of Trx system family members has been assessed in various cancers and linked to various clinicopathological variables, disease progression, treatment response and survival outcomes but information is lacking in brain tumours. Expression of the system was therefore examined, by immunohistochemistry in different brain tumour types, adult and paediatric cases, to determine if expression was of importance to clinical outcome. Trx system proteins were expressed, to variable levels, across all brain tumour types with significant variations in expression between different tumour types/grades/regions. High Trx reductase (TrxR) expression was linked to worse prognosis across all cohorts. High cytoplasmic TrxR expression was significantly associated with adverse overall survival (OS) in adult glioblastoma (P = 0.027) and paediatric low-grade glioma (LGG) patients (P = 0.012). High expression of nuclear TrxR, cytoplasmic and nuclear Trx and Trx-interacting protein (TxNIP) was associated with improved OS in paediatric LGGs (P = 0.031, P < 0.001, P = 0.044 and P = 0.018, respectively). For patients with high-grade gliomas, both high cytoplasmic TrxR and Trx expression were associated with poor OS (P = 0.002 and P = 0.007, respectively). In medulloblastoma, high expression of cytoplasmic TrxR and Trx and nuclear Trx was associated with worse prognosis (P = 0.013, P = 0.033 and P = 0.007, respectively); with cytoplasmic TrxR and nuclear Trx remaining so in multivariate analysis (P = 0.009 and P = 0.013, respectively). The consistent finding that high levels of cytoplasmic TrxR are associated with a worse prognosis across all cohorts suggests that TrxR is an important therapeutic target in brain cancers.

Retrospective assessment of cyclin-dependent kinase 5 mRNA and protein expression and its association with patient survival in breast cancer

Cyclin‐dependent kinase 5 (Cdk5) is an atypical member of the cyclin‐dependent kinase family and functions as a serine/threonine kinase that can be activated by non‐cyclin binding activators p35 or p39. Cdk5 expression and activity has been linked with the development and progression of cancer; however, its expression in breast cancer has not been fully described. Protein expression of Cdk5 was determined in a large cohort of early‐stage invasive breast cancer tumours (n = 1110) with long‐term follow‐up data using immunohistochemistry. Expression of CDK5 mRNA was assessed in the METABRIC cohort (n = 1980). Low nuclear and cytoplasmic expression of Cdk5 expression was significantly associated with shorter breast cancer‐specific survival (P = .004 and P = .001, respectively). Importantly, low nuclear and cytoplasmic expression of Cdk5 remained associated with survival in multivariate analysis, including potentially confounding factors (hazard ratio (HR) = 0.612, 95% confidence interval (CI) = 0.418‐0.896, P = .011 and HR = 0.507, 95% CI = 0.318‐0.809, P = .004, respectively). In addition, low nuclear and cytoplasmic expression of Cdk5 was significantly associated with clinicopathological criteria associated with adverse patient prognosis. Low CDK5 mRNA expression was associated with shorter patient survival (P = .005) in the METABRIC cohort; no associations between copy gain or loss and survival were observed. These data suggest that low Cdk5 expression is associated with poor clinical outcome of breast cancer patients and may be of clinical relevance.

Clinicopathological and prognostic significance of Ras association and pleckstrin homology domains 1 (RAPH1) in breast cancer

BACKGROUND

Ras association and pleckstrin homology domains 1 (RAPH1) is involved in cytoskeleton regulation and re-epithelialisation in invasive carcinoma and, therefore, may play a key role in carcinogenesis and metastasis. We, herein, investigated the biological and clinical significance of RAPH1 in breast cancer using large annotated cohorts.

METHODS

The clinicopathological and prognostic significance of RAPH1 was assessed at the genomic and transcriptomic levels using The Cancer Genome Atlas (TCGA) dataset (n = 1039) and the results were validated using the Molecular taxonomy of breast cancer international consortium (METABRIC) cohort (n = 1980). RAPH1 protein expression was evaluated by immunohistochemistry in a large, well-characterised cohort of early-stage breast cancer (n = 1040).

RESULTS

In both the TCGA and METABRIC cohorts, RAPH1 mRNA expression and RAPH1 copy number alteration were strongly correlated. RAPH1 mRNA overexpression was significantly correlated with high expression of adhesion and EMT markers including CDH1, TGFβ1 and CD44. RAPH1 mRNA overexpression was a significant predictor of a poor prognosis (Hazard ratio 3.88; p = 0.049). High RAPH1 protein expression was associated with higher grade tumours with high proliferation index, triple negative phenotype and high E-cadherin expression. High RAPH1 protein expression was an independent predictor of shorter survival (Hazard ratio 4.37; p = 0.037).

CONCLUSIONS

High RAPH1 expression is correlated with aggressive breast cancer phenotypes and provides independent prognostic value in invasive breast cancer.

Low expression of G protein-coupled oestrogen receptor 1 (GPER) is associated with adverse survival of breast cancer patients

G protein-coupled oestrogen receptor 1 (GPER), also called G protein-coupled receptor 30 (GPR30), is attracting considerable attention for its potential role in breast cancer development and progression. Activation by oestrogen (17β-oestradiol; E2) initiates short term, non-genomic, signalling events both in vitro and in vivo. Published literature on the prognostic value of GPER protein expression in breast cancer indicates that further assessment is warranted. We show, using immunohistochemistry on a large cohort of primary invasive breast cancer patients (n=1245), that low protein expression of GPER is not only significantly associated with clinicopathological and molecular features of aggressive behaviour but also significantly associated with adverse survival of breast cancer patients. Furthermore, assessment of GPER mRNA levels in the METABRIC cohort (n=1980) demonstrates that low GPER mRNA expression is significantly associated with adverse survival of breast cancer patients. Using artificial neural networks, genes associated with GPER mRNA expression were identified; these included notch-4 and jagged-1. These results support the prognostic value for determination of GPER expression in breast cancer.

Caspase-3 and caspase-8 expression in breast cancer: caspase-3 is associated with survival

Impaired apoptosis is one of the hallmarks of cancer. Caspase-3 and -8 are key regulators of the apoptotic response and have been shown to interact with the calpain family, a group of cysteine proteases, during tumorigenesis. The current study sought to investigate the prognostic potential of caspase-3 and -8 in breast cancer, as well as the prognostic value of combinatorial caspase and calpain expression. A large cohort (n = 1902) of early stage invasive breast cancer patients was used to explore the expression of caspase-3 and -8. Protein expression was examined using standard immunohistochemistry on tissue microarrays. High caspase-3 expression, but not caspase-8, is significantly associated with adverse breast cancer-specific survival (P = 0.008 and P = 0.056, respectively). Multivariate analysis showed that caspase-3 remained an independent factor when confounding factors were included (hazard ratio (HR) 1.347, 95% confidence interval (CI) 1.086–1.670; P = 0.007). The analyses in individual subgroups demonstrated the significance of caspase-3 expression in clinical outcomes in receptor positive (ER, PR or HER2) subgroups (P = 0.001) and in non-basal like subgroup (P = 0.029). Calpain expression had been previously assessed. Significant association was also found between high caspase-3/high calpain-1 and breast cancer-specific survival in the total patient cohort (P = 0.005) and basal-like subgroup (P = 0.034), as indicated by Kaplan–Meier analysis. Caspase-3 expression is associated with adverse breast cancer-specific survival in breast cancer patients, and provides additional prognostic values in distinct phenotypes. Combinatorial caspase and calpain expression can predict worse prognosis, especially in basal-like phenotypes. The findings warrant further validation studies in independent multi-centre patient cohorts.

The calpain system is associated with survival of breast cancer patients with large but operable inflammatory and non-inflammatory tumours treated with neoadjuvant chemotherapy

The calpains are a family of intracellular cysteine proteases that function in a variety of important cellular functions, including cell signalling, motility, apoptosis and survival. In early invasive breast cancer expression of calpain-1, calpain-2 and their inhibitor, calpastatin, have been associated with clinical outcome and clinicopathological factors.The expression of calpain-1, calpain-2 and calpastatin was determined using immunohistochemistry on core biopsy samples, in a cohort of large but operable inflammatory and non-inflammatory primary breast cancer patients treated with neoadjuvant chemotherapy. Information on treatment and prognostic variables together with long-term clinical follow-up was available for these patients. Diagnostic pre-chemotherapy core biopsy samples and surgically excised specimens were available for analysis.Expression of calpastatin, calpain-1 or calpain-2 in the core biopsies was not associated with breast cancer specific survival in the total patient cohort; however, in patients with non-inflammatory breast cancer, high calpastatin expression was significantly associated with adverse breast cancer-specific survival (P=0.035), as was low calpain-2 expression (P=0.031). Low calpastatin expression was significantly associated with adverse breast cancer-specific survival of the inflammatory breast cancer patients (P=0.020), as was low calpain-1 expression (P=0.003).In conclusion, high calpain-2 and low calpastatin expression is associated with improved breast cancer-specific survival in non-inflammatory large but operable primary breast cancer treated with neoadjuvant chemotherapy. In inflammatory cases, high calpain-1 and high calpastatin expression is associated with improved breast cancer-specific survival. Determining the expression of these proteins may be of clinical relevance. Further validation, in multi-centre cohorts of breast cancer patients treated with neoadjuvant chemotherapy, is warranted.

High nuclear MSK1 is associated with longer survival in breast cancer patients

Purpose

Mitogen- and stress-activated kinases (MSKs) are important substrates of the mitogen-activated protein kinase (MAPK)-activated protein kinase family. MSK1 and MSK2 are both nuclear serine/threonine protein kinases, with MSK1 being suggested to potentially play a role in breast cancer cell proliferation, cell cycle progression, cell migration, invasion and tumour growth. The aim of the current study was to assess MSK1 protein expression in breast cancer tumour specimens, evaluating its prognostic significance.

Methods

A large cohort of 1902 early stage invasive breast cancer patients was used to explore the expression of MSK1. Protein expression was examined using standard immunohistochemistry on tissue microarrays.

Results

Low MSK1 protein expression was associated with younger age (P = 0.004), higher tumour grade (P < 0.001), higher Nottingham Prognostic Index scores (P = 0.007), negative ER (P < 0.001) and PR (P < 0.001) status, and with triple-negative (P < 0.001) and basal-like (P < 0.001) phenotypes. Low MSK1 protein expression was significantly associated with shorter time to distant metastasis (P < 0.001), and recurrence (P = 0.013) and early death due to breast cancer (P = 0.01). This association between high MSK1 expression and improved breast cancer-specific survival was observed in the whole cohort (P = 0.009) and in the HER2-negative and non-basal like tumours (P = 0.006 and P = 0.024, respectively). Multivariate analysis including other prognostic variables indicated that MSK1 is not an independent marker of outcome.

Conclusions

High MSK1 is associated with improved breast cancer-specific survival in early stage invasive breast cancer patients, and has additional prognostic value in HER2-negative and non-basal like disease. Although not an independent marker of outcome, we believe such findings and significant associations with well-established negative prognostic factors (age, grade, Nottingham Prognostic Index, hormone receptor status, time to distant metastasis, recurrence and triple-negative/basal-like status) warrant further examination and validation in independent patient cohorts.

IL-6 and IL-10 are associated with good prognosis in early stage invasive breast cancer patients

Macrophage-associated cytokines play an important role in cancer metastasis; however, the functions of interleukins (IL) 6 and 10 in breast cancer (BC) progression and metastasis are not clear. In this study the roles of IL-6/IL-10 in regulating vascular invasion and their prognostic significance in BC are investigated. MDA-MB-231 and MCF-7 migration (± IL-6 or IL-10) was assessed by scratch wound assay. Cancer cell adhesion to IL-6/IL-10 stimulated blood and lymphatic endothelial cells (EC) was investigated. Expression of IL-6 /IL-10 was assessed using immunohistochemistry in an annotated cohort of early stage BC (n = 1380) and associations with clinicopathological variables and clinical outcome evaluated. IL-6 did not alter BC cell migration however a dose-dependent inhibition in MDA-MB-231 migration with IL-10 treatment was observed (P = 0.03). BC cells were more adhesive to blood vs lymphatic EC, however, IL-6/IL-10 had no effect on adhesion patterns. High expression of IL-6/IL-10 was associated with clinicopathological criteria (e.g. hormone receptor status, all P < 0.05), improved disease-free survival (DFS; P < 0.05) and improved BC-specific survival (BCSS; only IL-6, P = 0.017). However, neither IL-6 nor IL-10 expression were independent prognostic factors from multivariate analysis. In BC subgroups, IL-6 and IL-10 were good prognosticators in terms of DFS in non-basal, non-triple-negative (non-TN), ER-positive, PgR-positive (only IL-10), and Her-2-negative (only IL-6) BC (all P < 0.05). IL-6 was associated with improved BCSS in non-basal, ER-positive and non-TN BC (all P < 0.05).

Rho-GTPase activating-protein 18: a biomarker associated with good prognosis in invasive breast cancer

BACKGROUND

The prognostic value of lymphovascular invasion (LVI) in breast cancer (BC) has been demonstrated in several independent studies. However, identification of driver molecules for LVI remains a challenging task. Large-scale transcriptomic profiling of histologically validated LVI can potentially identify genes that regulate LVI.

METHODS

Integrative bio-informatics analyses of the METABRIC study were performed utilising a subset of strictly defined LVI using histological and immunohistochemical (IHC) criteria. ARHGAP18 was among the top differentially expressed genes between LVI+ and LVI- BC with a 1.8-fold change. The prognostic impact of ARHGAP18 gene expression was assessed in the METABRIC data set (n=1980) and externally validated using the online BC gene expression data sets utilising bc-GenExMiner v4.0 (n=2016). Subsequently, ARHGAP18 protein expression was assessed on a large cohort of invasive BC (n=959) with long-term follow-up using IHC.

RESULTS

Pooled analysis of ARHGAP18 mRNA expression showed that overexpression was associated with better outcome (P<0.001, hazard ratio (HR)=0.82, 95% CI 0.75-0.90). ARHGAP18 protein was expressed in the cytoplasm and nuclei of the tumour cells and its expression was positively associated with good prognostic variables. Lack of cytoplasmic expression showed associations with LVI (P=0.006), epithelial-mesenchymal transition and the HER+ subtype (P=0.01). Loss of nuclear expression was associated with higher grade, HER2+ and high Ki67LI (P=0.001). Cytoplasmic and nuclear expression showed a positive association with improved survival independent of other variables (P=0.01, HR=0.74, 95% CI 0.60-87).

CONCLUSIONS

ARHGAP18 expression at transcriptomic and protein levels is associated with improved patients' outcomes whose deregulation may play a role in tumour progression and the development of LVI in BC. Further assessment of its potential therapeutic value in BC is warranted.

Abstract 5210: Differential cytotoxic effects of Piperlongumine analogues and their radiotherapeutic response in breast cancer

Background: Breast cancer is the most common cancer in women in the United Kingdom. The glutathione (GSH) system is a major redox buffering system involved in regulating radioresponse of cancer cells. Overexpression has been shown to cause multidrug and radiation resistance. Its modulation may increase radiosensitivity and improve radiotherapy efficacy. Piperlongumine (PL) can reportedly inhibit GSH system function and reduce proliferation of a variety cancer cells in vitro. The current study investigates novel PL analogues to determine efficacy in triple-negative (TNBC) and luminal breast cancer cell lines, as both single agents and in combination with ionising radiation.

Methods: Two novel PL analogues (LH91 and LH92) were used along with the parental drug, PL. Cell proliferation assays were conducted in MDA-MB-231 (TNBC) and T47D (luminal) lines at various drug concentrations and times. At 48hr post treatment, cells were also assessed for clonogenic survival. Clonogenic radiosensitisation was assessed by treating with PL agents or L-buthionine-S, R-sulfoximine (BSO, a well characterised GSH radiosensitiser) for 48hr then irradiation with 0-8Gy X-rays. ROS levels were evaluated using H2DCFDA flow cytometry following IC50 drug treatment alone or with subsequent exposure to 1mM H2O2 for 1hr.

Results: PL, LH91 and LH92 inhibited proliferation and decreased clonogenic survival in both lines. From proliferation assays, MDA-MB-231 cells were more sensitive to PL at 48hr (P=0.047) and 72hr (P=0.01) with an IC50 dose of approx. 4μM versus approx. 12μM in T47D’s. There was a significant difference between IC50 doses of LH91 in MDA-MB-231 (5μM) and T47D (12μM) cell lines at 72hr (P=0.006), however this was not observed at 48hr treatment (P=0.178). In contrast, there was no differential sensitivity of LH92 in cell proliferation between the two cell lines at 48 and 72hr. Interestingly, in clonogenic assays, MDA-MB-231’s were more sensitive to LH92 (P=0.01) with an IC50 of 4μM versus 11μM in T47D’s. There were no significant differences in clonogenic survival between each line after treatment with PL or LH91. No radiosensitisation was observed with PL or PL analogues in MDA-MBA-231 however BSO, as a drug comparator, enhanced radiation response with a sensitizer enhancement ratio (SER) of 1.13 at 1% iso-survival. Radiation and drug combinations in T47D cells are ongoing. There were no changes in ROS levels with the drug alone in MDA-MB-231; however, with subsequent exposure of H2O2, there was a 1.7-fold increase in ROS level with LH91 at 48hr (P=0.002).

Conclusion: The TNBC cell line is more sensitive to the cytotoxic effect of PL agents (PL and LH91 in cell proliferation and LH92 in clonogenic assays) in comparison to the luminal cell line; however no altered radiosensitisation was observed. The mechanism of such differential sensitivity is yet to be determined.

Note: This abstract was not presented at the meeting.

Citation Format: Nurul Akmaryanti Abdullah, John Moses, Li Chen Han, Sarah Storr, Aula Ammar, Stewart G. Martin. Differential cytotoxic effects of Piperlongumine analogues and their radiotherapeutic response in breast cancer [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 5210. doi:10.1158/1538-7445.AM2017-5210

Abstract 890: The role of calpastatin isoforms in breast cancer progression

Calpastatin is the endogenous inhibitor of the ubiquitously expressed m-calpain and μ-calpain. Both of them are important regulators of various cellular pathways including proliferation, apoptosis, adhesion, and migration. Dysregulation of the calpain system is associated with a wide range of pathologies including tumour invasion and metastasis. In breast cancer, down-regulation of calpastatin mRNA, in particular an exon 3 containing variant, is associated with lymphatic vessel invasion which is the predominant form of lymphovascular invasion (LVI) (96%), a critical initial step of metastases. The current project seeks to determine the role that individual calpastatin isoforms play in regulating breast cancer cell migration and endothelial interactions to understand processes involved in regulating LVI.

Seven breast cancer cell lines were assessed for calpain system protein expression (calpain-1, -2, -4 and calpastatin) and calpastatin (CAST) mRNA expression (total CAST, CASTexon3, CAST I, II and III) by Western blotting and qRT-PCR, respectively. T47D and MDA-MB-231 cell lines showed low calpastatin but high calpain expression. From haptotaxis cell migration data, T47D migrated more slowly than MDA-MB-231 (35.49±6.14 and 80.34±5.52 percent wound closure at 24 hours post-scratch respectively) (P value=0.0233). These cell lines, that represent different subtypes of breast cancer (luminal and basal respectively), were therefore selected to study the role of differential calpastatin type/isoform expression.

GFP-tagged XL and Leader domains of calpastatin type I, II and III, with or without exon 3 were overexpressed in each cell line. The different calpastatin types show differential subcellular localization. In MDA-MB-231, type I, III, IΔ3, IIIΔ3 were expressed generally in cytoplasm whereas type II and IIΔ3 were located as punctate nuclear invaginations. To assess if overexpression of the different calpastatin types cause phenotypic changes, full length HA-tagged calpastatin type I, II and III were transfected into MDA-MB-231 and T47D and stable clones produced. Thus far stable type II overexpression in MDA-MB-231 and type III in T47D have been obtained with others under single cell selection. The localization of full length type II in MDA-MB-231 was similar to the localization of the truncated form that showing a strong single perinuclear signal. In T47D, the full length and truncated type III also show similarly localization that expressed throughout the cytoplasm. For the effect of calpastatin types on cell proliferation, calpastatin type II in MDA-MB-231, and type III in T47D, had no significant effect on cell doubling time when compared to respective controls (P value=0.6400 and 0.8874, respectively). According to preliminary studies, calpastatin type II seems to have no effect on clonogenicity of MDA-MB-231. Such effect on T47D and other phenotypic changes involved in regulating LVI of transfected cell are being examined.

Citation Format: Bhudsaban Sukkarn, Sarah Storr, Ian O. Ellis, Kirsty Jewell, Tim Parr, Stewart G. Martin. The role of calpastatin isoforms in breast cancer 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 890. doi:10.1158/1538-7445.AM2017-890

Macrophage-derived interleukin-1beta promotes human breast cancer cell migration and lymphatic adhesion in vitro

Lymphovascular invasion (LVI), encompassing blood and lymphatic vessel invasion, is an important event in tumourigenesis. Macrophages within the tumour microenvironment are linked to the presence of LVI and angiogenesis. This study investigates the role of macrophage-derived, caspase-1-dependent interleukin-1beta (IL-1β) in an in vitro model of LVI. IL-1β significantly augmented the adhesion and transmigration of breast cancer cell lines MCF7 and MDA-MB-231 across endothelial cell barriers. MDA-MB-231 and MCF7 showed a higher percentage of adhesion to lymphatic endothelial cells than blood endothelial cells following endothelial cell IL-1β stimulation (P < 0.001 and P < 0.0001, respectively). Supernatants from activated macrophages increased the adhesion of tumour cells to lymphatic and blood endothelium. Secretion of IL-1β was caspase-1 dependent, and treatment with caspase-1 inhibitor reduced IL-1β production by 73% and concomitantly reduced tumour cell adhesion to levels obtained with resting macrophages. Transmigration of MDA-MB-231 cells across blood and lymphatic endothelial monolayers was significantly increased following IL-1β stimulation. Furthermore, supernatants from activated macrophages increased transmigration of MDA-MB-231 cells across endothelial monolayers, which was abolished by caspase-1 inhibition. IL-1β stimulation of tumour cells significantly increased their migratory ability and a significant increase in migration was observed when MDA-MB-231 cells were stimulated with macrophage conditioned media (two of three donors). Results demonstrate that macrophage production of IL-1β plays an important role in the migration of breast cancer cells and their adhesion to, and transmigration across, blood and lymphatic endothelial cells. Results suggest that IL-1β may play a role in the adhesion to lymphatic endothelial cells in particular.

RORγt+ Innate Lymphoid Cells Promote Lymph Node Metastasis of Breast Cancers

Cancer cells tend to metastasize first to tumor-draining lymph nodes, but the mechanisms mediating cancer cell invasion into the lymphatic vasculature remain little understood. Here, we show that in the human breast tumor microenvironment (TME), the presence of increased numbers of RORγt+ group 3 innate lymphoid cells (ILC3) correlates with an increased likelihood of lymph node metastasis. In a preclinical mouse model of breast cancer, CCL21-mediated recruitment of ILC3 to tumors stimulated the production of the CXCL13 by TME stromal cells, which in turn promoted ILC3-stromal interactions and production of the cancer cell motile factor RANKL. Depleting ILC3 or neutralizing CCL21, CXCL13, or RANKL was sufficient to decrease lymph node metastasis. Our findings establish a role for RORγt+ILC3 in promoting lymphatic metastasis by modulating the local chemokine milieu of cancer cells in the TME. Cancer Res; 77(5); 1083-96. ©2017 AACR.

FKBPL: a marker of good prognosis in breast cancer

FK506-binding protein-like (FKBPL) has established roles as an anti-tumor protein, with a therapeutic peptide based on this protein, ALM201, shortly entering phase I/II clinical trials. Here, we evaluated FKBPL's prognostic ability in primary breast cancer tissue, represented on tissue microarrays (TMA) from 3277 women recruited into five independent retrospective studies, using immunohistochemistry (IHC). In a meta-analysis, FKBPL levels were a significant predictor of BCSS; low FKBPL levels indicated poorer breast cancer specific survival (BCSS) (hazard ratio (HR) = 1.30, 95% confidence interval (CI) 1.14–1.49, p < 0.001). The prognostic impact of FKBPL remained significant after adjusting for other known prognostic factors (HR = 1.25, 95% CI 1.07–1.45, p = 0.004). For the sub-groups of 2365 estrogen receptor (ER) positive patients and 1649 tamoxifen treated patients, FKBPL was significantly associated with BCSS (HR = 1.34, 95% CI 1.13–1.58, p < 0.001, and HR = 1.25, 95% CI 1.04–1.49, p = 0.02, respectively). A univariate analysis revealed that FKBPL was also a significant predictor of relapse free interval (RFI) within the ER positive patient group, but it was only borderline significant within the smaller tamoxifen treated patient group (HR = 1.32 95% CI 1.05–1.65, p = 0.02 and HR = 1.23 95% CI 0.99–1.54, p = 0.06, respectively). The data suggests a role for FKBPL as a prognostic factor for BCSS, with the potential to be routinely evaluated within the clinic.

Calpain-1 is associated with adverse relapse free survival in breast cancer: a confirmatory study

AIMS

Calpain-1 is a ubiquitously expressed calcium-activated intracellular cysteine protease. Altered expression of calpain system proteins has been implicated in cancer progression and response to chemotherapy.

METHODS AND RESULTS

The aim of the current study was to confirm previous data that suggested that calpain-1 expression is associated with relapse-free survival in trastuzumab-treated breast cancer patients (n = 93). An expanded patient cohort from Nottingham (n = 194; including 72 of the previous cohort) and an independent patient cohort from Newcastle (n = 87) were used. All patients received trastuzumab following adjuvant therapy according to local guidelines with expression of calpain-1 investigated using standard immunohistochemistry. Results show that calpain-1 expression is associated with relapse-free survival in both the Nottingham (P = 0.01) and Newcastle (P = 0.019) cohorts, with high expression associated with adverse relapse-free survival. Expression was also associated with poor relapse-free survival when patient cohorts were combined (n = 281, P = 0.01). Calpain-1 remained, from multivariate analysis, an independent marker for relapse-free survival in the Newcastle cohort [hazard ratio (HR) = 5.169; 95% confidence interval (CI) 1.468-18.200; P = 0.011].

CONCLUSIONS

Calpain-1 expression is associated with poor relapse-free survival in breast cancer patients treated with trastuzumab. Further work is warranted to standardize and develop methodology with a view to potentially introducing assessment of this important biomarker into clinical practice.

Involvement of metformin and AMPK in the radioresponse and prognosis of luminal versus basal-like breast cancer treated with radiotherapy

Metformin is under evaluation as a potential anticancer agent. Expression of total and phospho(Thr172)-adenosine monophosphate-activated kinase-α (AMPKα and pAMPKα(Thr172) respectively), a main metformin target, was examined in radiotherapy treated breast cancers and metformin's ability to modulate Trx system expression and breast cancer radiosensitivity evaluated in vitro.

AMPKα and pAMPKα(Thr172) expression was assessed using a discovery (n=166) and validation cohort (n=609). Metformin's role in regulating radioresponse, and Trx family expression, was examined via clonogenic assays and Western blots. Intracellular reactive oxygen species (ROS) levels, cell cycle progression and apoptosis were assessed by flow cytometry.

High AMPKα expression associated with improved local recurrence-free (P=0.019), relapse-free (P=0.016) and breast cancer-specific survival (P=0.000065) and was, from multivariate analysis, an independent prognostic factor from the discovery cohort. From the validation cases AMPKα expression associated with relapse-free and breast cancer-specific survival in luminal breast cancers. Metformin substantially increased radiosensitivity, intracellular ROS levels and reduced Trx expression, in luminal breast cancer cells, but had little effect on basal phenotype cells.

In conclusion, high AMPKα expression associates with improved prognosis, especially in luminal breast cancer. Metformin preferentially radiosensitises luminal breast cancer cells, potentially due to alterations to intracellular ROS levels via modulation of Trx family protein expression.

Chk1 phosphorylated at serine345 is a predictor of early local recurrence and radio-resistance in breast cancer

Radiation-induced DNA damage activates the DNA damage response (DDR). DDR up-regulation may predict radio-resistance and increase the risk of early local recurrence despite radiotherapy in early stage breast cancers. In 1755 early stage breast cancers, DDR signalling [ATM, ATR, total Ckh1, Chk1 phosphorylated at serine(345) (pChk1), Chk2, p53], base excision repair [PARP1, POLβ, XRCC1, FEN1, SMUG1], non-homologous end joining (Ku70/Ku80, DNA-PKcs) and homologous recombination [RAD51, BRCA1, γH2AX, BLM, WRN, RECQL5, PTEN] protein expression was correlated to time to early local recurrence. Pre-clinically, radio-sensitization by inhibition of Chk1 activation by ATR inhibitor (VE-821) and inhibition of Chk1 (V158411) were investigated in MDA-MB-231 (p53 mutant) and MCF-7 (p53 wild-type) breast cancer cells. In the whole cohort, 208/1755 patients (11.9%) developed local recurrence of which 126 (61%) developed local recurrence within 5 years of initiation of primary therapy. Of the 20 markers tested, only pChk1 and p53 significantly associated with early local recurrence (p value = 0.015 and 0.010, respectively). When analysed together, high cytoplasmic pChk1-nuclear pChk1 (p = 0.039), high cytoplasmic pChk1-p53 (p = 0.004) and high nuclear pChk1-p53 (p = 0.029) co-expression remain significantly linked to early local recurrence. In multivariate analysis, cytoplasmic pChk1 level independently predicted early local recurrence (p = 0.025). In patients who received adjuvant local radiotherapy (n = 949), p53 (p = 0.014) and high cytoplasmic pChk1-p53 (p = 0.017) remain associated with early local recurrence. Pre-clinically, radio-sensitisation by VE-821 or V158411 was observed in both MCF-7 and MDA-MB-231 cells and was more pronounced in MCF-7 cells. We conclude that pChk1 is a predictive biomarker of radiotherapy resistance and early local recurrence.

Calpain in Breast Cancer: Role in Disease Progression and Treatment Response

The calpains are a family of intracellular cysteine proteases that function in a wide array of cellular activities, including cytoskeletal remodelling, survival and apoptosis. The ubiquitously expressed micro (µ)-calpain and milli (m)-calpain are archetypal family members that require calcium for function and can be inhibited by their endogenous inhibitor calpastatin. This review describes the role of the calpain system in the prognosis of breast cancer and disease progression, in addition to the role of the calpain system in the response to breast cancer treatments, including chemotherapeutic, endocrine and targeted therapies.

Analysis of lymphatic and blood vessel invasion biomarkers in T1 esophagogastric adenocarcinomas for improved patient prognostication

Lymphovascular invasion (LVI) in T1 esophagogastric adenocarcinoma may predict risk of recurrence despite definitive treatment with surgery or endoscopic resection. Podoplanin and CD34 are emerging biomarkers of lymphatic and blood vessel invasion, respectively, and could be adopted to refine LVI assessment. A consecutive series of 65 patients with T1 adenocarcinomas diagnosed at Nottingham University Hospitals were investigated. T1 tumors from 43/65 patients who received primary surgery only were suitable for LVI evaluation by hematoxylin and eosin (H&E) staining as well as by CD34 and Podoplanin immunohistochemistry. LVI was correlated to clinicopathological features and recurrence free survival. H&E staining detected LVI in 11.6% (5/43) of T1 tumors. CD34 and Podoplanin immunohistochemistry significantly improved LVI detection to 25.6% (11/43). Compared with LVI by H&E, immunohistochemical evaluation of blood vessel invasion (CD34) or lymphatic vessel invasion (Podoplanin) was significantly associated with higher grade (P = 0.005), submucosal invasion (T1b) (P = 0.018), lymph node positivity (N1) (P = 0.029) and poor recurrence free survival (P = 0.0003). Our study provides evidence that CD34 and Podoplanin immunohistochemistry could improve LVI detection and allow better prognostication of patients and optimum selection of definitive treatment. Larger multicenter studies are required for further validation that could have significant clinical implications.

The clinicopathological and gene expression patterns associated with ulceration of primary melanoma

Ulceration of primary melanomas is associated with poor prognosis yet is reported to predict benefit from adjuvant interferon. To better understand the biological processes involved, clinicopathological factors associated with ulceration were determined in 1804 patients. From this cohort, 348 primary tumor blocks were sampled to generate gene expression data using a 502-gene cancer panel and 195 blocks were used for immunohistochemistry to detect macrophage infiltration and vessel density. Gene expression results were validated using a whole genome array in two independent sample sets. Ulceration of primary melanomas was associated with more proliferative tumors, tumor vessel invasion, and increased microvessel density. Infiltration of tumors with greater number of macrophages and gene expression pathways associated with wound healing and up-regulation of pro-inflammatory cytokines suggests that ulceration is associated with tumor-related inflammation. The relative benefit from interferon reported in patients with ulcerated tumors may reflect modification of signaling pathways involved in inflammation.

Low calpain-9 is associated with adverse disease-specific survival following endocrine therapy in breast cancer

Background

The calpains are intracellular cysteine proteases that function in a variety of important cellular functions, including signalling, motility, apoptosis and survival. In breast cancer high calpain-1 and calpain-2 expression has been associated with adverse clinical outcome. Calpain-9 was thought to be exclusively expressed in the digestive tract; however recent studies have shown that this protein is also expressed in breast tissue.

Methods

We investigated the expression of calpain-9 in a large cohort of early stage breast cancer patients (n = 783) using immunohistochemistry on a tissue microarray. Patients had long-term follow-up information available for analysis.

Results

Low expression of calpain-9 was associated with patients over 40 years of age (P = 0.025), smaller tumour size (P = 0.001), lower tumour stage (P = 0.009), a more favourable Nottingham Prognostic Index value (P = 0.002) and positive oestrogen receptor status (P = 0.014). Calpain-9 expression was not associated with survival in the total patient cohort, however low calpain-9 expression was associated with adverse survival in patients who received endocrine therapy (P = 0.033), which remained significant in multivariate Cox regression analysis accounting for potential confounding factors (hazard ratio (HR) = 0.56, 95% confidence interval (95% CI) = 0.36-0.89, P = 0.013). Low calpain-9 expression was also associated with adverse survival in patients with an intermediate Nottingham Prognostic Index value (P = 0.009), and remained so in multivariate analysis (HR = 0.54, 95% CI = 0.36-0.82, P = 0.003).

Conclusions

This study suggests that calpain-9 may play a role in breast cancer and that low expression is associated with poorer patient clinical outcome following endocrine therapy. Validation studies are warranted as determining expression of calpain-9 may provide important prognostic information.

Prognostic significance of lymphatic invasion in lymph node-positive breast carcinoma: findings from a large case series with long-term follow-up using immunohistochemical endothelial marker

The poor prognostic significance of lymphatic invasion (LI) in breast carcinoma (BC) as a whole and in lymph node (LN)-negative patients in particular has been recognized in several studies; however, its prognostic role in LN-positive patients is still questionable. Aim of the current study was to assess prognostic role of LI in LN-positive BC specimens. Sections from non-selected 557 LN-positive BC specimens were stained with antibody to podoplanin/D2-40. LI was identified and correlated with clinicopathological features and patients' outcome. Twenty-year overall survival (OS), disease-free interval (DFI), and development of distant metastasis (DM) or recurrence were known for all patients. LI was detected in 262/557 (47%) of specimens ranging from 1 to 350 lesion per tumor section. Its presence was associated with higher grade tumors (P<0.0001), negative hormonal receptors (P<0.0001), high HER-2 expression (P=0.006), and with increased number of positive LNs (P=0.019). In the whole LN-positive BC, presence of LI was a poor prognostic factor for OS, DFI, and development of DM both in univariate and in multivariate analysis. In further stratification of patients, LI was associated with poorer prognosis in patients with single positive LN and not in patients with >1 positive LN. In T1N1 stage, LI was highly associated with poor OS (P=0.002), DFI (P<0.0001), and DM (P<0.0001). In T2N1 patients, LI was associated only with poorer DFI (P=0.037) but not with death or DM. In the two former patient groups, LI lost significance in multivariate analysis. In conclusion, LI is a poor prognostic factor in LN-positive BC particularly for patients having single positive LN. LI therefore would add further prognostic significance when considered in treatment in those patients. We recommend incorporation of LI in breast carcinoma staging and in prognostic indices.

Redox proteins and radiotherapy

Although conventional radiotherapy can directly damage DNA and other organic molecules within cells, most of the damage and the cytotoxicity of such ionising radiation, comes from the production of ions and free radicals produced via interactions with water. This 'indirect effect', a form of oxidative stress, can be modulated by a variety of systems within cells that are in place to, in normal situations, maintain homeostasis and redox balance. If cancer cells express high levels of antioxidant redox proteins, they may be more resistant to radiation and so targeting such systems may be a profitable strategy to increase therapeutic efficacy of conventional radiotherapy. An overview, with exemplars, of the main systems regulating redox homeostasis is supplied and discussed in relation to their use as prognostic and predictive biomarkers, and how targeting such proteins and systems may increase radiosensitivity and, potentially, improve the radiotherapeutic response.

Expression of the calpain system is associated with poor clinical outcome in gastro-oesophageal adenocarcinomas

BACKGROUND

Surgery is critical in the management of gastro-oesophageal cancer, and the addition of neo-adjuvant chemotherapy has proved to be of benefit. The calpain system has been implicated in tumour progression and response to various anti-cancer therapies, and therefore expression of the system was determined in this tumour type.

METHODS

Two cohorts of gastro-oesophageal adenocarcinomas were investigated for calpain-1, calpain-2, calpain-9 and calpastatin expression using conventional immunohistochemistry. 88 patients who received neo-adjuvant chemotherapy and 140 patients who received surgery alone were investigated using a tissue microarray approach.

RESULTS

Calpain-1, calpain-2 and calpastatin expression was associated with adverse cancer-specific survival in the neo-adjuvant cohort (P = 0.004, P = 0.001 and P = 0.012 respectively); which remained significant in multivariate analysis (Hazard ratio (HR) = 0.337; 95% confidence interval (CI) = 0.140-0.81; P = 0.015, HR = 0.375; 95% CI = 0.165-0.858; P = 0.020 and HR = 0.481; 95% CI = 0.257-0.900; P = 0.022 respectively). Calpain-1 and calpastatin expression was also associated with adverse cancer specific survival in the primary surgery cohort (P = 0.001 and P = 0.013 respectively); which remained significant in multivariate analysis (HR = 0.309; 95% CI = 0.159-0.601; P = 0.001 and HR = 0.418; 95% CI = 0.205-0.850; P = 0.016 respectively). Calpain-9 expression was not associated with cancer-specific survival in the neo-adjuvant and primary surgery cohorts.

CONCLUSION

Determining the expression levels of calpain-1, calpain-2 and calpastatin may provide clinically relevant prognostic information for gastro-oesophageal adenocarcinomas; these findings warrant further studies in larger cohorts of patients.

Critical research gaps and translational priorities for the successful prevention and treatment of breast cancer

INTRODUCTION

Breast cancer remains a significant scientific, clinical and societal challenge. This gap analysis has reviewed and critically assessed enduring issues and new challenges emerging from recent research, and proposes strategies for translating solutions into practice.

METHODS

More than 100 internationally recognised specialist breast cancer scientists, clinicians and healthcare professionals collaborated to address nine thematic areas: genetics, epigenetics and epidemiology; molecular pathology and cell biology; hormonal influences and endocrine therapy; imaging, detection and screening; current/novel therapies and biomarkers; drug resistance; metastasis, angiogenesis, circulating tumour cells, cancer 'stem' cells; risk and prevention; living with and managing breast cancer and its treatment. The groups developed summary papers through an iterative process which, following further appraisal from experts and patients, were melded into this summary account.

RESULTS

The 10 major gaps identified were: (1) understanding the functions and contextual interactions of genetic and epigenetic changes in normal breast development and during malignant transformation; (2) how to implement sustainable lifestyle changes (diet, exercise and weight) and chemopreventive strategies; (3) the need for tailored screening approaches including clinically actionable tests; (4) enhancing knowledge of molecular drivers behind breast cancer subtypes, progression and metastasis; (5) understanding the molecular mechanisms of tumour heterogeneity, dormancy, de novo or acquired resistance and how to target key nodes in these dynamic processes; (6) developing validated markers for chemosensitivity and radiosensitivity; (7) understanding the optimal duration, sequencing and rational combinations of treatment for improved personalised therapy; (8) validating multimodality imaging biomarkers for minimally invasive diagnosis and monitoring of responses in primary and metastatic disease; (9) developing interventions and support to improve the survivorship experience; (10) a continuing need for clinical material for translational research derived from normal breast, blood, primary, relapsed, metastatic and drug-resistant cancers with expert bioinformatics support to maximise its utility. The proposed infrastructural enablers include enhanced resources to support clinically relevant in vitro and in vivo tumour models; improved access to appropriate, fully annotated clinical samples; extended biomarker discovery, validation and standardisation; and facilitated cross-discipline working.

CONCLUSIONS

With resources to conduct further high-quality targeted research focusing on the gaps identified, increased knowledge translating into improved clinical care should be achievable within five years.

Redox environment, free radical, and oxidative DNA damage

SIGNIFICANCE

Effective redox homeostasis is critical, and disruption of this process can have important cellular consequences. An array of systems protect the cell from potentially damaging reactive oxygen species (ROS), however if these systems are overwhelmed, for example, in aberrantly functioning cells, ROS can have a number of detrimental consequences, including DNA damage. Oxidative DNA damage can be repaired by a number of DNA repair pathways, such as base excision repair (BER).

RECENT ADVANCES

The role of ROS in oxidative DNA damage is well established, however, there is an emerging role for ROS and the redox environment in modulating the efficiency of DNA repair pathways targeting oxidative DNA lesions.

CRITICAL ISSUES

Oxidative DNA damage and modulation of DNA damage and repair by the redox environment are implicated in a number of diseases. Understanding how the redox environment plays such a critical role in DNA damage and repair will allow us to further understand the far reaching cellular consequence of ROS.

FUTURE DIRECTIONS

In this review, we discuss the detrimental effects of ROS, oxidative DNA damage repair, and the redox systems that exist to control redox homeostasis. We also describe how DNA pathways can be modulated by the redox environment and how the redox environment and oxidative DNA damage plays a role in disease.

Thioredoxin interacting protein and its association with clinical outcome in gastro-oesophageal adenocarcinoma

The overall prognosis for operable gastro-oesophageal adenocarcinoma remains poor and therefore neoadjuvant chemotherapy has become the standard of care, in addition to radical surgery. Certain anticancer agents (e.g. anthracyclines and cisplatin) generate damaging reactive oxygen species as by-products of their mechanism of action. Drug effectiveness can therefore depend upon the presence of cellular redox buffering systems that are often deregulated in cancer. The expression of the redox protein, thioredoxin interacting protein, was assessed in gastro-oesophageal adenocarcinomas. Thioredoxin interacting protein expression was assessed using conventional immunohistochemistry on a tissue microarray of 140 adenocarcinoma patients treated by primary surgery alone and 88 operable cases treated with neoadjuvant chemotherapy. In the primary surgery cases, high thioredoxin interacting protein expression associated with a lack of lymph node involvement (p=0.005), no perineural invasion (p=0.030) and well/moderate tumour differentiation (p=0.033). In the neoadjuvant tumours, high thioredoxin interacting protein expression was an independent marker for improved disease specific survival (p=0.002) especially in cases with anthracycline-based regimes (p=0.008). This study highlights the potential of thioredoxin interacting protein as a biomarker for response in neoadjuvant treated gastro-oesophageal adenocarcinoma and may represent a useful therapeutic target due to its association with tumour progression.

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In primary surgery cases, high TxNIP associates with disease progression markers.

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TxNIP expression is higher in tumours from chemotherapy treated patients.

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High TxNIP associates with improved survival in neoadjuvant treated cases.

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High TxNIP expression may be a biomarker for anthracycline based treatment.

Calpain-2 expression is associated with response to platinum based chemotherapy, progression-free and overall survival in ovarian cancer

Ovarian cancer is routinely treated with surgery and platinum-based chemotherapy. Resistance is a major obstacle in the efficacy of this chemotherapy regimen and the ability to identify those patients at risk of developing resistance is of considerable clinical importance. The expression of calpain-1, calpain-2 and calpastatin were determined using standard immunohistochemistry on a tissue microarray of 154 primary ovarian carcinomas from patients subsequently treated with platinum-based adjuvant chemotherapy. High levels of calpain-2 expression was significantly associated with platinum resistant tumours (P = 0.031). Furthermore, high expression of calpain-2 was significantly associated with progression-free (P = 0.049) and overall survival (P = 0.006) in this cohort. The association between calpain-2 expression and overall survival remained significant in multivariate analysis accounting for tumour grade, stage, optimal debulking and platinum sensitivity (hazard ratio = 2.174; 95% confidence interval = 1.144–4.130; P = 0.018). The results suggest that determining calpain-2 expression in ovarian carcinomas may allow prognostic stratification of patients treated with surgery and platinum-based chemotherapy. The findings of this study warrant validation in a larger clinical cohort.

A comparative study of adhesion of melanoma and breast cancer cells to blood and lymphatic endothelium

BACKGROUND

Lymphovascular invasion (LVI) is an important step in the metastatic cascade; tumor cell migration and adhesion to blood and lymphatic vessels is followed by invasion through the vessel wall and subsequent systemic spread. Although primary breast cancers and melanomas have rich blood vascular networks, LVI is predominately lymphatic in nature. Whilst the adhesion of tumor cells to blood endothelium has been extensively investigated, there is a paucity of information on tumor cell adhesion to lymphatic endothelium.

METHODS AND RESULTS

Breast cancer (MDA-MB-231 and MCF7) and melanoma (MeWo and SKMEL-30) cell adhesion to lymphatic (hTERT-LEC and HMVEC dLy Neo) and blood (HUVEC and hMEC-1) endothelial cells were assessed using static adhesion assays. The effect of inflammatory conditions, tumor necrosis factor-α (TNF-α) stimulation of endothelial and tumor cells, on the adhesive process was also examined. In addition, the effects of TNF-α stimulation on tumor cell migration was investigated using haplotaxis (scratch wound) assays. Breast cancer and melanoma cells exhibited higher levels of adhesion to blood compared to lymphatic endothelial cells (p<0.001). TNF-α stimulation of endothelial cells, or of tumor cells alone, did not significantly alter tumor-endothelial cell adhesion or patterns. When both tumor and endothelial cells were stimulated with TNF-α, a significant increase in adhesion was observed (p<0.01), which was notably higher in the lymphatic cell models (p<0.001). TNF-α-stimulation of all tumor cell lines significantly increased their migration rate (p<0.01).

CONCLUSIONS

Results suggest that metastasis resultant from lymphatic vessel-tumor cell adhesion may be modulated by cytokine stimulation, which could represent an important therapeutic target in breast cancer and melanoma.

Calpain system protein expression in carcinomas of the pancreas, bile duct and ampulla

Background

Pancreatic cancer, including cancer of the ampulla of Vater and bile duct, is very aggressive and has a poor five year survival rate; improved methods of patient stratification are required.

Methods

We assessed the expression of calpain-1, calpain-2 and calpastatin in two patient cohorts using immunohistochemistry on tissue microarrays. The first cohort was composed of 68 pancreatic adenocarcinomas and the second cohort was composed of 120 cancers of the bile duct and ampulla.

Results

In bile duct and ampullary carcinomas an association was observed between cytoplasmic calpastatin expression and patient age (P = 0.036), and between nuclear calpastatin expression and increased tumour stage (P = 0.026) and the presence of vascular invasion (P = 0.043). In pancreatic cancer, high calpain-2 expression was significantly associated with improved overall survival (P = 0.036), which remained significant in multivariate Cox-regression analysis (hazard ratio = 0.342; 95% confidence interva l = 0.157-0.741; P = 0.007). In cancers of the bile duct and ampulla, low cytoplasmic expression of calpastatin was significantly associated with poor overall survival (P = 0.012), which remained significant in multivariate Cox-regression analysis (hazard ratio = 0.595; 95% confidence interval = 0.365-0.968; P = 0.037).

Conclusion

The results suggest that calpain-2 and calpastatin expression is important in pancreatic cancers, influencing disease progression. The findings of this study warrant a larger follow-up study.

Calpain system protein expression in basal-like and triple-negative invasive breast cancer

BACKGROUND

Basal-like and triple-negative breast tumours encompass an important clinical subgroup and biomarkers that can prognostically stratify these patients are required.

MATERIALS AND METHODS

We investigated two breast cancer tissue microarrays for the expression of calpain-1, calpain-2 and calpastatin using immunohistochemistry. The first microarray was comprised of invasive tumours from 1371 unselected patients, and the verification microarray was comprised of invasive tumours from 387 oestrogen receptor (ER)-negative patients.

RESULTS

The calpain system contains a number of proteases and an endogenous inhibitor, calpastatin. Calpain activity is implicated in important cellular processes including cytoskeletal remodelling, apoptosis and survival. Our results show that the expression of calpastatin and calpain-1 are significantly associated with various clinicopathological criteria including tumour grade and ER expression. High expression of calpain-2 in basal-like or triple-negative disease was associated with adverse breast cancer-specific survival (P = 0.003 and <0.001, respectively) and was verified in an independent cohort of patients. Interestingly, those patients with basal-like or triple-negative disease with a low level of calpain-2 expression had similar breast cancer-specific survival to non-basal- or receptor- (oestrogen, progesterone or human epidermal growth factor receptor 2 (HER2)) positive disease.

CONCLUSIONS

Expression of the large catalytic subunit of m-calpain (calpain-2) is significantly associated with clinical outcome of patients with triple-negative and basal-like disease.

The prognostic and predictive power of redox protein expression for anthracycline-based chemotherapy response in locally advanced breast cancer

Neoadjuvant chemotherapy has become the standard of care for locally advanced primary breast cancer. Anthracycline-based regimens have proven to be one of the most effective treatments in this setting. As certain cytotoxic antineoplastic agents, such as anthracyclines, generate reactive oxygen species as a by-product of their mechanism of action, we examined whether redox protein expression was involved in the response to anthracycline-based chemotherapy and with clinical outcome. Pre-treatment needle core biopsy and post-anthracycline treatment tumour sections were analysed from 98 cases. In all, 32 individuals had a complete clinical response and 17 had a complete pathological response. Immunohistochemical staining was performed for eight redox proteins: thioredoxin, thioredoxin reductase, thioredoxin interacting protein (TxNIP), glutathione S-transferase (GST) π, θ and α, catalase and manganese superoxide dismutase. GST π (P=0.05) and catalase (P=0.045) were associated with pathological complete response in pre-chemotherapy samples. TxNIP (P=0.017) and thioredoxin reductase (P=0.022) were independent prognostic factors for distant metastasis-free survival and TxNIP for overall survival (P=0.014). In oestrogen receptor negative patients that are known to have a poor overall survival, a considerably worse prognosis was seen in cases that exhibited low expression of TxNIP (P=0.000003), stratifying patients into more defined groups. This study indicates the importance of redox regulation in determining breast cancer response to anthracycline-based chemotherapy and provides ways of further stratifying pre-chemotherapy patients to potentially allow more tailored treatments.

Expression of angiogenic chemokines in ovarian clear cell carcinoma

AIMS

The aim of this study was to assess the expression of angiogenic chemokines (CXCR4/CXCL12) and the vascular endothelial growth factor in ovarian clear cell carcinoma, comparing levels against those in ovarian high-grade serous carcinoma.

MATERIAL AND METHODS

Tissue microarray samples from 136 cases of epithelial ovarian carcinoma (108 high-grade serous carcinoma and 28 clear cell carcinoma) were reviewed with World Health Organization histological criteria strictly applied to categorize cases according to histological subtype. Only cases without prior exposure to chemotherapy were included. Sections were stained with vascular endothelial growth factor, CXCR4, CXCL12 and assessed using conventional histological scoring (H-scoring).

RESULTS

  Patients with clear cell carcinoma presented at an early stage of the disease (74% stage 1 and 2) and had a significantly better progression-free (P=0.042) survival than those with high-grade serous carcinoma. Low expression profile of the tested markers was seen in cases of clear cell carcinoma contrary to that seen in high-grade serous carcinoma.

CONCLUSION

The current study reports, for the first time, the difference in expression of a set of angiogeneic prognostic markers between clear cell carcinoma and high-grade serous carcinoma, offering a possible explanation for the apparent chemotherapy resistance. These results are relevant for the design of future clinical studies of first-line treatment for patients with ovarian clear cell carcinoma.