Circulating sphingosine-1-phosphate and erythrocyte sphingosine kinase-1 activity as novel biomarkers for early prostate cancer detection

Background:

Current markers available for screening normal populations and for monitoring prostate cancer (PCa) treatment lack sensitivity and selectivity. Sphingosine-1-phosphate (S1P) is a circulating lipid second messenger involved in cell growth and migration, the immune response, angiogenesis, and malignant transformation.

Methods:

Eighty-eight patients with localised, locally advanced, or metastatic PCa were recruited into this prospective single-centre study. Plasma S1P levels were measured and compared with age-matched controls with benign prostate hyperplasia (BPH) (n=110) or with young healthy males with the very small chance of having PCa foci (n=20).

Results:

Levels of circulating S1P were significantly higher in healthy subjects (10.36±0.69 pmol per mg protein, P<0.0001) and patients with BPH (9.39±0.75, P=0.0013) than in patients with PCa (6.89±0.58, ANOVA, P=0.0019). Circulating S1P levels were an early marker of PCa progression to hormonal unresponsiveness and correlated with prostate-specific antigen (PSA) levels and lymph node metastasis. During the course of the study, nine patients have died of PCa. Importantly, their circulating S1P levels were significantly lower (5.11±0.75) than in the surviving patients (7.02±0.22, n=79, P=0.0439). Our data suggest that the decrease in circulating S1P during PCa progression may stem from a highly significant downregulation of erythrocyte sphingosine kinase-1 (SphK1) activity (2.14±0.17 pmol per mg protein per minute in PCa patients vs 4.7±0.42 in healthy individuals, P<0.0001), which may be a potential mechanism of cancer-induced anaemia.

Conclusion:

This current study has provided a potential mechanism for cancer-related anaemia and the first evidence that plasma S1P and erythrocyte SphK1 activity are the potential markers for the diagnosis, monitoring, and predicating for PCa mortality.     

Oestrogen receptors β1 and βcx have divergent roles in breast cancer survival and lymph node metastasis

Background:

The expression of oestrogen receptor (ER) α characterises a subset of breast cancers associated with good response to endocrine therapy. However, the clinical significance of the second ER, ERβ1, and its splice variant ERβcx is still unclear.

Methods:

We here report an assessment of ERα, ERβ1 and ERβcx by immunohistochemistry using quantitative digital image analysis of 340 primary tumours and corresponding sentinel lymph nodes.

Results:

No differences were seen in ER levels in primary tumours vs lymph node metastases. ERβ1 and ERβcx were equally distributed among age groups and tumour histological grades. Loss of ERβ1 in the primary tumour was strongly associated with poor survival. Its prognostic impact was particularly evident in young patients and in high-grade tumours. The worst outcome was seen in the tumours lacking both ERα and ERβ1. ERβcx expression in the primary tumour correlated with a higher risk of lymph node metastasis, and with poor survival when expressed in sentinel node lymphocytes.

Conclusions:

Our study reveals highly significant although antagonising roles of ERβ1 and ERβcx in breast cancer. Consequently, we suggest that the histopathological assessment of ERβ1 is of value as a prognostic and potentially predictive biomarker.     

Increased mortality in HER2 positive, oestrogen receptor positive invasive breast cancer: a population-based study

Background:

This study assessed the impact of human epidermal growth factor receptor 2 (HER2) status on the outcomes in an unselected population of breast cancer patients who did not receive HER2-targeted therapy.

Methods:

HER2 status by immunohistochemistry and fluorescence in situ hybridisation was compared with clinicopathological data, overall survival (OS) and disease-free survival (DFS) for all patients presenting with breast cancer over 3 years.

Results:

In 865 patients (median follow up 6.02 years), HER2 positivity was identified in 13.3% of all cancers and was associated with higher tumour grade (P<10⁻⁸), lymphovascular invasion (P<0.001) and axillary nodal metastasis (P=0.003). There was a negative association with oestrogen-receptor (ER) and progesterone-receptor expression (P<10⁻⁸), but the majority (57%) of HER2+tumours were ER+HER2 positivity was associated with poorer OS (P=0.0046) and DFS (P=0.0001) confined to the lymph node-positive (LN+) and ER+ subgroups.

Conclusion:

HER2-positive cancers were less common in this population-based cohort than most selected series. The association of HER2 positivity with poor prognosis was confined to the ER+ and LN+ subgroups. The survival deficit for the 7.5% of patients with ER+/HER2+ cancer compared with ER+/HER2– patients points to a significant subgroup of women who may not (currently) be considered for HER2-directed therapy.     

Side-population cells in luminal-type breast cancer have tumour-initiating cell properties, and are regulated by HER2 expression and signalling

Background:

The expression of side-population (SP) cells and their relation to tumour-initiating cells (T-ICs) have been insufficiently studied in breast cancer (BC). We therefore evaluated primary cell cultures derived from patients and a panel of human BC cell lines with luminal- or basal-molecular signatures for the presence of SP and BC stem cell markers.

Methods:

The SPs from luminal-type BC were analysed for BC T-IC characteristics, including human epidermal growth factor receptor 2 (HER2), ERα, IGFBP7 expression and their ability to initiate tumours in non-obese diabetic severe combined immunodeficiency (NOD/SCID) mice. Pharmacological modulators were used to assess the effects of HER2 signalling and breast cancer-resistance protein (BCRP) expression on SPs.

Results:

The SP was more prevalent in the luminal subtype of BC compared with the basal subtype. HER2 expression was significantly correlated with the occurrence of an SP (r²=0.75, P=0.0003). Disappearance of SP in the presence of Ko143, a specific inhibitor of the ATP-binding cassette transporter BCRP, suggests that BCRP is the predominant transporter expressed in this population. The SP also decreased in the presence of HER2 signalling inhibitors AG825 or trastuzumab, strengthening the notion that HER2 contributed to the SP phenotype, likely through downstream AKT signalling. The SP cells from luminal-type MCF-7 cells with enforced expression of HER2, and primary cells with luminal-like properties from a BC patient, displayed enrichment in cells capable of repopulating tumours in NOD/SCID mice. Engraftment of SP cells was inhibited by pretreatment with AG825 or by in vivo treatment with trastuzumab.

Interpretation:

Our findings indicate an important role of HER2 in regulating SP and hence T-ICs in BC, which may account for the poor responsiveness of HER2-positive BCs to chemotherapy, as well as their aggressiveness.     

Upregulated FGFR1 expression is associated with the transition of hormone-naive to castrate-resistant prostate cancer

Background:

Prostate cancer (PC) represents a global health issue. Treatment for locally advanced and metastatic PC remains unsatisfactory. The androgen receptor (AR) has been validated in having a key role in both naïve and castrate-resistant PC (CRPC). However, the significance of other signalling pathways in CRPC is less well validated.

Methods:

To gain a better insight into the molecular signalling cascades involved in clinical CRPC, we performed gene expression profiling using the Illumina DASL assay and studied matched hormone-naive (HN) and CR prostate tumours (n=10 pairs). Ingenuity Pathways Analysis (IPA) was used to identify potential networks involved, and further validation was performed in in vitro cell models and clinical tumours.

Results:

Expression of 50 genes was significantly different between HN and CRPC. IPA revealed two networks of particular interest, including AR and FGFR1, respectively. FGFR1 expression was confirmed to be significantly upregulated in CRPC (P⩽0.005), and abnormal FGFR1 expression was associated with shorter time to biochemical relapse in HNPC (P=0.006) and less favourable disease-specific survival in CRPC (P=0.018).

Conclusion:

For the first time, our gene expression profiling experiment on archival tumour materials has identified upregulated FGFR1 expression to be associated with PC progression to the CR state.     

S100A9 expressed in ER?PgR? breast cancers induces inflammatory cytokines and is associated with an impaired overall survival

Background:

Breast cancer is the most common cancer form among women today. Depending on hormone receptor status, breast cancers are divided into different subtypes with vastly varying prognosis. S100A9 is a calcium-binding protein that is associated with inflammation and expressed not only in myeloid cells but also in some tumours. The role for S100A9 in the malignant cells is not well characterised; however, previous studies have shown that the protein could have important immune-modulating properties.

Methods:

Using a human breast cancer cohort consisting of 144 tumour samples and in vitro analysis of human breast cancer cell lines, we investigated the expression and function of S100A9 in human breast cancer.

Results:

We show that S100A9 expression in breast cancer correlated with the ER⁻PgR⁻ breast tumour subtype (P<0.001) and with Ki67 (P=0.024) and was expressed both in the malignant cells and in the tumour-infiltrating anti-inflammatory CD163⁺ myeloid cells (P<0.001). Stromal expression of S100A9 also correlated to nodal stage, tumour size and Her2 positivity. Within the ER⁻PgR⁻ subgroup, all Her2⁺ and EGFR⁺ tumours expressed S100A9 in the cytoplasm. Both cytoplasmic staining in the malignant cells as well as stromal S100A9 expression in myeloid cells correlated with a decreased overall survival in breast cancer patients. Furthermore, rS100A9 homodimers induced expression of pro-inflammatory cytokines (IL-6, IL-8 and IL-1β) in a TLR4- and EGFR-dependent manner in human breast cancer cells in vitro.

Conclusion:

We suggest that S100A9 could be viewed as a novel therapeutic target for patients with ER⁻PgR⁻ breast cancers.     

Effect of (Neo)adjuvant zoledronic acid on disease-free and overall survival in clinical stage II/III breast cancer

Background:

Despite neoadjuvant/adjuvant chemotherapy, women with resectable stage II/III breast cancer (BC) have high risk of recurrent disease. Recent data suggest that zoledronic acid (ZOL) therapy concurrent with adjuvant treatments may improve cancer-related outcomes in patients with BC.

Methods:

Disease-free survival (DFS; secondary end point) and overall survival (OS; tertiary end point) were evaluated in 119 women with stage II/III BC randomised to intravenous ZOL 4 mg every 3 weeks for 1 year or no ZOL (control) starting with the first chemotherapy cycle.

Results:

At 61.9 months'' median follow-up, there was no significant difference in recurrence or survival between study arms. However, time to recurrence or death (DFS) was significantly different between subgroups defined by oestrogen receptor (ER) status (interaction P=0.010 for DFS and 0.025 for OS). Hazard ratios (HRs) for disease recurrence and death were significantly less among patients with ER-negative (ER⁻) tumours who received ZOL vs no ZOL (DFS: HR=0.361, 95% confidence interval (CI) 0.148, 0.880; OS: HR=0.375, 95% CI 0.143, 0.985).

Conclusion:

ZOL administered with chemotherapy may improve DFS and OS in a subset of BC patients with ER⁻ tumours. This study was not powered to compare subgroups of patients; thus, these findings should be considered hypothesis generating.     

Epstein-Barr virus as a marker of biological aggressiveness in breast cancer

Purpose:

Although a potential role of the Epstein-Barr virus (EBV) in the pathogenesis of breast cancer (BC) has been underlined, results remain conflicting. Particularly, the impact of EBV infection on biological markers of BC has received little investigation.

Methods:

In this study, we established the frequency of EBV-infected BC using real-time quantitative PCR (RT–PCR) in 196 BC specimens. Biological and pathological characteristics according to EBV status were evaluated.

Results:

EBV DNA was present in 65 of the 196 (33.2%) cases studied. EBV-positive BCs tended to be tumours with a more aggressive phenotype, more frequently oestrogen receptor negative (P=0.05) and with high histological grade (P=0.01). Overexpression of thymidine kinase activity was higher in EBV-infected BC (P=0.007). The presence of EBV was weakly associated with HER2 gene amplification (P=0.08).

Conclusion:

Our study provides evidence for EBV-associated BC undergoing distinct carcinogenic processes, with more aggressive features.     

Androgen receptors are acquired by healthy postmenopausal endometrial epithelium and their subsequent loss in endometrial cancer is associated with poor survival

Background:

Endometrial cancer (EC) is a hormone-driven disease, and androgen receptor (AR) expression in high-grade EC (HGEC) and metastatic EC has not yet been described.

Methods:

The expression pattern and prognostic value of AR in relation to oestrogen (ERα and ERβ) and progesterone (PR) receptors, and the proliferation marker Ki67 in all EC subtypes (n=85) were compared with that of healthy and hyperplastic endometrium, using immunohistochemisty and qPCR.

Results:

Compared with proliferative endometrium, postmenopausal endometrtial epithelium showed significantly higher expression of AR (P<0.001) and ERα (P=0.035), which persisted in hyperplastic epithelium and in low-grade EC (LGEC). High-grade EC showed a significant loss of AR (P<0.0001), PR (P<0.0001) and ERβ (P<0.035) compared with LGEC, whilst maintaining weak to moderate ERα. Unlike PR, AR expression in metastatic lesions was significantly (P=0.039) higher than that in primary tumours. Androgen receptor expression correlated with favourable clinicopathological features and a lower proliferation index. Loss of AR, with/without the loss of PR was associated with a significantly lower disease-free survival (P<0.0001, P<0.0001, respectively).

Conclusions:

Postmenopausal endometrial epithelium acquires AR whilst preserving other steroid hormone receptors. Loss of AR, PR with retention of ERα and ERβ may promote the unrestrained growth of HGEC. Androgen receptor may therefore be a clinically relevant prognostic indicator and a potential therapeutic target in EC.     

Pregnane X receptor suppresses proliferation and tumourigenicity of colon cancer cells

Background:

Pregnane X receptor (PXR) is a nuclear receptor that regulates the metabolism and disposition of various xenobiotics and endobioitics. We investigated a novel PXR function in regulating colon tumourigenesis in this study.

Methods:

Histochemistry, transfection, cell proliferation assay, anchorage-α-dependent assay, xenograft, immunohistochemistry, immunofluorescence flow cytometry.

Results:

Using histochemistry analysis, we found that PXR expressions were lost or greatly diminished in many colon tumours. Ectopic expression of human PXR through stable transfection of PXR into colon cancer cell line HT29 significantly inhibited cell proliferation as determined by cell proliferation assay and anchorage-independent assay. Pregnane X receptor suppressed significantly HT29 xenograft tumour growth in nude mice compared with control (310±6.2 vs 120±6 mg, P<0.01). Immunohistochemistry and immunofluorescence analysis of Ki-67 on excised xenograft tumour tissues showed that PXR inhibited cancer cell proliferation. Furthermore, expressions of PXR and Ki-67 were mutually exclusive. The flow cytometry analysis indicated that PXR caused G₀/G₁ cell-cycle arrest. p21^WAF1/CIP1 expression was markedly elevated whereas E2F1 expression was inhibited by PXR.

Conclusion:

PXR inhibits the proliferation and tumourigenicity of colon cancer cells by controlling cell cycle at G₀/G₁ cell phase by regulating p21^WAF1/CIP1 and E2F/Rb pathways.     

1H nuclear magnetic resonance spectroscopy characterisation of metabolic phenotypes in the medulloblastoma of the SMO transgenic mice

Background:

Human medulloblastomas exhibit diverse molecular pathology. Aberrant hedgehog signalling is found in 20–30% of human medulloblastomas with largely unknown metabolic consequences.

Methods:

Transgenic mice over-expressing smoothened (SMO) receptor in granule cell precursors with high incidence of exophytic medulloblastomas were sequentially followed up by magnetic resonance imaging (MRI) and characterised for metabolite phenotypes by ¹H MR spectroscopy (MRS) in vivo and ex vivo using high-resolution magic angle spinning (HR-MAS) ¹H MRS.

Results:

Medulloblastomas in the SMO mice presented as T₂ hyperintense tumours in MRI. These tumours showed low concentrations of N-acetyl aspartate and high concentrations of choline-containing metabolites (CCMs), glycine, and taurine relative to the cerebellar parenchyma in the wild-type (WT) C57BL/6 mice. In contrast, ¹H MRS metabolite concentrations in normal appearing cerebellum of the SMO mice were not different from those in the WT mice. Macromolecule and lipid ¹H MRS signals in SMO medulloblastomas were not different from those detected in the cerebellum of WT mice. The HR-MAS analysis of SMO medulloblastomas confirmed the in vivo ¹H MRS metabolite profiles, and additionally revealed that phosphocholine was strongly elevated in medulloblastomas accounting for the high in vivo CCM.

Conclusions:

These metabolite profiles closely mirror those reported from human medulloblastomas confirming that SMO mice provide a realistic model for investigating metabolic aspects of this disease. Taurine, glycine, and CCM are potential metabolite biomarkers for the SMO medulloblastomas. The MRS data from the medulloblastomas with defined molecular pathology is discussed in the light of metabolite profiles reported from human tumours.     

Activation of the EGFR/ERK pathway in high-grade mucoepidermoid carcinomas of the salivary glands

Background:

Mucoepidermoid carcinoma (MEC) shows differences in biological behaviour depending mainly on its histological grade. High-grade tumours usually have an aggressive biological course and they require additional oncological treatment after surgery.

Methods:

In a series of 43 MECs of the salivary glands, we studied the epidermal growth factor receptor (EGFR) gene by using dual-colour chromogenic in situ hybridisation (CISH). Moreover, we assessed the protein expressions of the EGFR and the activated extracellular signal-regulated kinases (pERK1/2) by using immunohistochemistry. These results were correlated with the histological grade of the tumours and the outcome of the patients.

Results:

The CISH study demonstrated a high-EGFR gene copy number, with balanced chromosome 7 polysomy, in 8 out of 11 high-grade MECs (72.7%), whereas 27 low-grade and 15 intermediate-grade tumours had a normal EGFR gene copy number (P<0.001). The EGFR gene gains correlated with disease-free interval (P=0.003) and overall survival of the patients (P=0.019). The EGFR protein expression had a significant correlation with the histological grade of the tumours but not with the outcome of the patients. The pERK1/2 expression correlated with histological grade of tumours (P<0.001), disease-free interval (P=0.004) and overall survival (P=0.001).

Conclusions:

The EGFR/ERK pathway is activated in high-grade MECs with aggressive behaviour. Patients with these tumours who require oncological treatment in addition to surgery could benefit from EGFR and mitogen-activated protein kinase pathway inhibitors.     

The interrelationships between Src, Cav-1 and RhoGD12 in transitional cell carcinoma of the bladder

Background:

The aim of this current study was to assess the expression and activity of Src family kinases, focal adhesion kinase (FAK), caveolin (Cav-1) and RhoGD12 in bladder cancer.

Methods:

Fifty-eight patients with a new diagnosis of bladder cancer undergoing transurethral resection were included. Immunohistochemical staining was utilised to assess expression of c-Src, dephosphorylated (SrcY⁵³⁰), phosphorylated Src (Y⁴¹⁹), phosphorylated FAK (FAK Y⁸⁶¹), Cav-1 and RhoGD12. Expression was assessed using the weighted histoscore method.

Results:

High expression of dephosphorylated Y⁵²⁷, phosphorylated Y⁴¹⁶ and phosphorylated FAK Y⁸⁶¹ in the membrane were associated with increased cancer-specific survival (P=0. 01, P=0.001, P=0.008, respectively) and expression of Y⁴¹⁶ in the membrane was an independent factor on multivariate analysis when combined with known clinical parameters (P=0.008, HR 0.288, 95% CI 0.11–0.72).

Conclusion:

These results demonstrate that in contrast to other solid tumours, activation of the Src family members and downstream signalling proteins are associated with a good prognosis in transitional cell carcinoma of the bladder, and activated Src has a positive relationship with RhoGD12.     

Do type 1 receptor tyrosine kinases inform treatment choice? A prospectively planned analysis of the TEAM trial

Background:

Epidermal growth factor receptors contribute to breast cancer relapse during endocrine therapy. Substitution of aromatase inhibitors (AIs) may improve outcomes in HER-positive cancers.

Methods:

Tissue microarrays were constructed. Quantitative analysis of HER1, HER2, and HER3 was performed. Data were analysed relative to disease-free survival and treatment using outcomes at 2.75 and 6.5 years.

Results:

Among 4541 eligible samples, 4225 (93%) had complete HER1–3 data. Overall, 5% were HER1-positive, 13% HER2-positive, and 21% HER3-positive; 32% (n=1351) overexpressed at least one HER receptor. In the HER1–3-negative subgroup, the hazard ratio (HR) for upfront exemestane vs tamoxifen at 2.75 years was 0.67 (95% confidence interval (CI), 0.52–0.87), in the HER1–3-positive subgroup, the HR was 1.15 (95% CI, 0.85–1.56). A prospectively planned treatment-by-marker analysis demonstrated a significant interaction between HER1–3 and treatment at 2.75 years (HR=0.58; 95% CI, 0.39–0.87; P=0.008), as confirmed by multivariate regression analysis adjusting for prognostic factors (HR=0.55; 95% CI, 0.36–0.85; P=0.005). This effect was time dependent.

Conclusion:

In the 2.75 years prior to switching patients initially treated with tamoxifen to exemestane, a significant treatment-by-marker effect exists between AI/tamoxifen treatment and HER1-3 expression, suggesting HER expression could be used to select appropriate endocrine treatment at diagnosis to prevent or delay early relapses.     

ADAM10: a new player in breast cancer progression?

Background:

The ADAM proteases are best known for their role in shedding the extracellular domain of transmembrane proteins. Among the transmembrane proteins shed by ADAM10 are notch, HER2, E-cadherin, CD44, L1 and the EGFR ligands, EGF and betacellulin. As cleavage of several of these proteins has been implicated in cancer formation and progression, we hypothesised that ADAM10 is also involved in these processes.

Methods:

ADAM10 expression was decreased by RNA interference and the effects of this on cell numbers, invasion and migration were determined. We also examined the effect of ADAM10 inhibition on breast cancer cell line invasion and migration.

Results:

Using the triple-negative (TN) breast cancer cell lines, BT20, MDA-MB-231 and the non-TN cell line MDA-MB-453, knockdown of ADAM10 expression significantly decreased in vitro migration (P<0.01; for each cell line). Similarly, treatment with the ADAM10-selective inhibitor GI254023X reduced migration in the three cell lines (for BT20, P<0.001; for MDA-MB-231, P=0.005; for MDA-MB-453, P=0.023). In contrast, neither knockdown of ADAM10 nor treatment with the ADAM10-selective inhibitor GI254023X significantly affected cell numbers. Using extracts of primary breast cancers, higher levels of ADAM10 were found more frequently in high-grade vs low-grade tumours (P<0.001) and in oestrogen receptor (ER)-negative compared with ER-positive tumours (P=0.005). Analysis of pooled publicly available data sets found that high levels of ADAM10 mRNA were associated with adverse outcome in patients with the basal subtype of breast cancer.

Conclusions:

Based on our combined cell line and breast cancer extract data, we conclude that ADAM10 is likely to be involved in breast cancer progression, especially in the basal subtype.