Cyclooxygenase-2 expression in primary breast cancers predicts dissemination of cancer cells to the bone marrow

The Efficacy and Safety of Celecoxib in Addition to Standard Cancer Therapy: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

The purpose of this meta-analysis was to evaluate the efficacy and safety of celecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor, in addition to standard anticancer therapy. Randomized controlled trials (RCTs) that evaluated the efficacy and safety of celecoxib-combined cancer therapy were systematically searched in PubMed and Embase databases. The endpoints were overall survival (OS), progression-free survival (PFS), disease-free survival (DFS), objective response rate (ORR), disease control rate (DCR), pathological complete response (pCR), and adverse events (AEs). The results of 30 RCTs containing 9655 patients showed limited benefits in celecoxib-combined cancer therapy. However, celecoxib-combined palliative therapy prolonged PFS in epidermal growth factor receptor (EGFR) wild-type patients (HR = 0.57, 95%CI = 0.35–0.94). Moreover, despite a slight increase in thrombocytopenia (RR = 1.35, 95%CI = 1.08–1.69), there was no increase in other toxicities. Celecoxib combined with adjuvant therapy indicated a better OS (HR = 0.850, 95%CI = 0.725–0.996). Furthermore, celecoxib plus neoadjuvant therapy improved the ORR in standard cancer therapy, especially neoadjuvant therapy (overall: RR = 1.13, 95%CI = 1.03–1.23; neoadjuvant therapy: RR = 1.25, 95%CI = 1.09–1.44), but not pCR. Our study indicated that adding celecoxib to palliative therapy prolongs the PFS of EGFR wild-type patients, with good safety profiles. Celecoxib combined with adjuvant therapy prolongs OS, and celecoxib plus neoadjuvant therapy improves the ORR. Thus, celecoxib-combined cancer therapy may be a promising therapy strategy.

Quantification of the Landscape for Revealing the Underlying Mechanism of Intestinal-Type Gastric Cancer

Gastric cancer is a daunting disease with a tragic impact on global health. It is the fourth most common cancer and has become the second most frequent cause of cancer death in recent times. According to the Lauren classification, gastric cancer can be classified into two types: intestinal and diffuse. Intestinal-type gastric cancer (IGC) is more common in elderly people, and atrophic gastritis (AG) and intestinal metaplasia (IM) have been proven to be the main premalignant causes of intestinal-type gastric cancer. In turn, Helicobacter pylori infection has been identified as the most significant cause of AG and IM. In this study, we determine the mechanism of IGC progression and how H. pylori infection induces IGC. Through researching the relevant literature, we identified the key genes associated with gastric cancer and the specific genes associated with IGC. We then use hese genes to build up a gene regulatory network for IGC. Based on this gene regulatory network, we quantify the IGC landscape. Within this landscape, there are three stable states, which are classified as the normal, AG, and gastric cancer states. Through landscape topography, we can determine the biological features and progression process of IGC. To investigate the influence of H. pylori infection on IGC, we simulated different degrees of H. pylori infection. As the H. pylori infection becomes more serious, the landscape topography changes accordingly. A fourth state, named the intestinal metaplasia (IM) state, emerges on the landscape and is associated with a very high risk of developing gastric cancer. The emergence of this state is due to the interactions/regulations among genes. Through variations in the landscape topography, we can determine the influence of H. pylori infection on IGC. Finally, we use global sensitivity analysis to research the regulations most sensitive to IGC prevention or therapies. This study presents a new approach and a novel model with which to explore the mechanism of IGC. The simulations of different degrees of H. pylori infection can provide us with a systematic view of IGC progression. The key regulations found can give us some insight and guidance for clinical trials and experimental studies.

Metformin suppresses breast cancer growth via inhibition of cyclooxygenase-2

Pre-clinical and on-going trials have indicated the advantage of using metformin as an anticancer drug alone or in combination with other chemotherapeutics for the treatment of patients with breast cancer. However, the mechanisms by which metformin attenuates tumorigenesis remain to be further elucidated. The present study investigated the anticancer effects of metformin in breast cancer and identified potential molecular targets of metformin using western blotting and immunohistochemical analysis. Metformin significantly decreased tumor cell proliferation in vitro and suppressed tumor growth in vivo. Moreover, it induced the activation of AMP-induced protein kinase and suppression of phosphorylated-eukaryotic translation initiation factor 4E-binding protein 1 (p-4E-BP1), a downstream effector of the mTOR signaling pathway, and decreased cyclin D1 levels in in vitro and in vivo experimental models. Additionally, metformin inhibited cyclooxygenase (COX)-2 expression. Clinically, high expression levels of COX-2 and p-4E-BP1 in tissues of patients with breast cancer were significantly associated with enhanced lymphatic metastasis and distant metastasis. Thus, the current data suggested that metformin may have potential value as a synergistic therapy targeting both the COX-2 and mTOR signaling pathways.

The Role of Inflammation in Breast and Prostate Cancer Metastasis to Bone

Tumor metastasis to bone is a common event in multiple forms of malignancy. Inflammation holds essential functions in homeostasis as a defense mechanism against infections and is a strategy to repair injured tissue and to adapt to stress conditions. However, exaggerated and/or persistent (chronic) inflammation may eventually become maladaptive and evoke diseases such as autoimmunity, diabetes, inflammatory tissue damage, fibrosis, and cancer. In fact, inflammation is now considered a hallmark of malignancy with prognostic relevance. Emerging studies have revealed a central involvement of inflammation in several steps of the metastatic cascade of bone-homing tumor cells through supporting their survival, migration, invasion, and growth. The mechanisms by which inflammation favors these steps involve activation of epithelial-to-mesenchymal transition (EMT), chemokine-mediated homing of tumor cells, local activation of osteoclastogenesis, and a positive feedback amplification of the protumorigenic inflammation loop between tumor and resident cells. In this review, we summarize established and evolving concepts of inflammation-driven tumorigenesis, with a special focus on bone metastasis.

Low-dose Aspirin, Nonsteroidal Anti-inflammatory Drugs, Selective COX-2 Inhibitors and Breast Cancer Recurrence

BACKGROUND

Aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs), and selective COX-2 inhibitors may improve outcomes in breast cancer patients. We investigated the association of aspirin, NSAIDs, and use of selective COX-2 inhibitors with breast cancer recurrence.

METHODS

We identified incident stage I-III Danish breast cancer patients in the Danish Breast Cancer Cooperative Group registry, who were diagnosed during 1996-2008. Prescriptions for aspirin (>99% low-dose aspirin), NSAIDs, and selective COX-2 inhibitors were ascertained from the National Prescription Registry. Follow-up began on the date of breast cancer primary surgery and continued until the first of recurrence, death, emigration, or 1 January 2013. We used Cox regression models to compute hazard ratios (HR) and corresponding 95% confidence intervals (95% CI) associating prescriptions with recurrence, adjusting for confounders.

RESULTS

We identified 34,188 breast cancer patients with 233,130 person-years of follow-up. Median follow-up was 7.1 years; 5,325 patients developed recurrent disease. Use of aspirin, NSAIDs, or selective COX-2 inhibitors was not associated with the rate of recurrence (HRadjusted aspirin = 1.0, 95% CI = 0.90, 1.1; NSAIDs = 0.99, 95% CI = 0.92, 1.1; selective COX-2 inhibitors = 1.1, 95% CI = 0.98, 1.2), relative to nonuse. Prediagnostic use of the exposure drugs was associated with reduced recurrence rates (HRaspirin = 0.92, 95% CI = 0.82, 1.0; HRNSAIDs = 0.86, 95% CI = 0.81, 0.91; HRsCOX-2inhibitors = 0.88, 95% CI = 0.83, 0.95).

CONCLUSIONS

This prospective cohort study suggests that post diagnostic prescriptions for aspirin, NSAIDs, and selective COX-2 inhibitors have little or no association with the rate of breast cancer recurrence. Prediagnostic use of the drugs was, however, associated with a reduced rate of breast cancer recurrence.

Small GTPase RBJ promotes cancer progression by mobilizing MDSCs via IL-6

RBJ has been identified to be dysregulated in gastrointestinal cancer and promotes tumorigenesis and progression by mediating nuclear accumulation of active MEK1/2 and sustained activation of ERK1/2. Considering that nuclear accumulation and constitutive activation of MEK/ERK not only promotes tumor progression directly, but also induces chronic inflammation, we wonder whether and how RBJ impairs host immune-surveillance via chronic inflammation and consequently supports tumor progression. Here, we report that higher expression of RBJ in human breast cancer tissue has been significantly correlated with poorer prognosis in breast cancer patients. The forced expression of RBJ promotes tumor growth and metastasis both in vitro and in vivo. In addition, more accumulation of immune suppressive cells but less antitumor immune cell subpopulations were found in spleen and tumor tissue derived from RBJ force-expressed tumor-bearing mice. Furthermore, forced RBJ expression significantly promotes tumor cell production of pro-inflammatory cytokine IL-6 by constitutive activating MEK/ERK signaling pathway. Accordingly, RBJ knockdown significantly decreases tumor growth and metastasis in vitro and in vivo, with markedly reduced production of IL-6. Administration of anti-IL-6 neutralizing antibody could reduce MDSCs accumulation in tumor tissue in vivo. Therefore, our results demonstrate that RBJ-mediated nuclear constitutive activation of ERK1/2 leads to persistent production of IL-6 and increase of MDSCs recruitment, contributing to promotion of tumor growth and metastasis. These results suggest that RBJ contributes to tumor immune escape, maybe serving a potential target for design of antitumor drug.

Impact of cyclooxygenase-2 over-expression on the prognosis of breast cancer patients

OBJECTIVE

The aim of this present study was to assess the impact of COX-2 over-expression on breast cancer survival.

MATERIAL AND METHODS

Non-metastatic invasive breast cancer patients who received adequate loco-regional and systemic treatments were evaluated. Patients' demographic, clinical, pathologic, and treatment-related and survival data were retrieved from their hospital files. COX-2, estrogen/progesterone receptor (ER/PR), HER-2/neu expression and Ki67 index of the tumors were determined immunohistochemically. As the primary objective, COX-2 positive and negative patients were compared in terms of overall (OS), disease-free (DFS) and breast cancer-specific survival (BCSS). Secondary objectives were to assess the independent prognostic factors for survival. In addition, the correlation of COX-2 expression with conventional prognostic and predictive factors of breast cancer was assessed.

RESULTS

Two hundred and seventeen patients who underwent adequate breast cancer treatment between November 2004 and December 2013 were included in the study. The median follow-up was 37 months (range: 5-107). Eighty-one (37%) patients were COX-2 positive. OS, DFS, and BCSS were similar in COX-2 positive and negative patients. Ki67 index and age were significantly correlated with COX-2 expression (r=-0.116; p=0.02; r=0.159; p=0.02). PR expression was found to be the only independent factor for predicting OS, tumor size and molecular subtype classification were found to be the only independent factors for predicting DFS, and PR expression was found to be the only independent factor for predicting BCSS.

CONCLUSION

Among the independent predictive and prognostic factors of breast cancer, COX-2 over-expression was only correlated with Ki67 index and age.

Effects of letrozole on breast cancer micro-metastatic tumor growth in bone and lung in mice inoculated with murine 4T1 cells

Breast cancer (BC) is the leading cancer in women worldwide. Metastasis occurs in stage IV BC with bone and lung being common metastatic sites. Here we evaluate the effects of the aromatase inhibitor letrozole on BC micro-metastatic tumor growth in bone and lung metastasis in intact and ovariectomized (OVX) mice with murine estrogen receptor negative (ER-) BC cells inoculated in tibia. Forty-eight BALB/c mice were randomly assigned to one of four groups: OVX, OVX + Letrozole, Intact, and Intact + Letrozole, and injected with 4T1 cells intra-tibially. Letrozole was subcutaneously injected daily for 23 days at a dose of 1.75 µg/g body weight. Tumor progression was monitored by bioluminescence imaging (BLI). Following necropsy, inoculated tibiae were scanned via µCT and bone response to tumor was scored from 0 (no ectopic mineralization/osteolysis) to 5 (extensive ectopic mineralization/osteolysis). OVX mice had higher tibial pathology scores indicative of more extensive bone destruction than intact mice, irrespective of letrozole treatment. Letrozole decreased serum estradiol levels and reduced lung surface tumor numbers in intact animals. Furthermore, mice receiving letrozole had significantly fewer tumor colonies and fewer proliferative cells in the lung than OVX and intact controls based on H&E and Ki-67 staining, respectively. In conclusion, BC-inoculated OVX animals had higher tibia pathology scores than BC-inoculated intact animals and letrozole reduced BC metastases to lungs. These findings suggest that, by lowering systemic estrogen level and/or by interacting with the host organ, the aromatase inhibitor letrozole has the potential to reduce ER- BC metastasis to lung.

The impact of low-dose carcinogens and environmental disruptors on tissue invasion and metastasis

The purpose of this review is to stimulate new ideas regarding low-dose environmental mixtures and carcinogens and their potential to promote invasion and metastasis. Whereas a number of chapters in this review are devoted to the role of low-dose environmental mixtures and carcinogens in the promotion of invasion and metastasis in specific tumors such as breast and prostate, the overarching theme is the role of low-dose carcinogens in the progression of cancer stem cells. It is becoming clearer that cancer stem cells in a tumor are the ones that assume invasive properties and colonize distant organs. Therefore, low-dose contaminants that trigger epithelial-mesenchymal transition, for example, in these cells are of particular interest in this review. This we hope will lead to the collaboration between scientists who have dedicated their professional life to the study of carcinogens and those whose interests are exclusively in the arena of tissue invasion and metastasis.

Protein deregulation associated with breast cancer metastasis

Breast cancer is one of the most prevalent malignancies worldwide. It consists of a group of tumor cells that have the ability to grow uncontrollably, overcome replicative senescence (tumor progression) and metastasize within the body. Metastases are processes that consist of an array of complex gene dysregulation events. Although these processes are still not fully understood, the dysregulation of a number of key proteins must take place if the tumor cells are to disseminate and metastasize. It is now widely accepted that future effective and innovative treatments of cancer metastasis will have to encompass all the major components of malignant transformation. For this reason, much research is now being carried out into the mechanisms that govern the malignant transformation processes. Recent research has identified key genes involved in the development of metastases, as well as their mechanisms of action. A detailed understanding of the encoded proteins and their interrelationship generates the possibility of developing novel therapeutic approaches. This review will focus on a select group of proteins, often deregulated in breast cancer metastasis, which have shown therapeutic promise, notably, EMT, E-cadherin, Osteopontin, PEA3, Transforming Growth Factor Beta (TGF-β) and Ran.

Bone marrow fat: linking adipocyte-induced inflammation with skeletal metastases

Adipocytes are important but underappreciated components of bone marrow microenvironment, and their numbers greatly increase with age, obesity, and associated metabolic pathologies. Age and obesity are also significant risk factors for development of metastatic prostate cancer. Adipocytes are metabolically active cells that secrete adipokines, growth factors, and inflammatory mediators; influence behavior and function of neighboring cells; and have a potential to disturb local milleu and dysregulate normal bone homeostasis. Increased marrow adiposity has been linked to bone marrow inflammation and osteoporosis of the bone, but its effects on growth and progression of prostate tumors that have metastasized to the skeleton are currently not known. This review focuses on fat-bone relationship in a context of normal bone homeostasis and metastatic tumor growth in bone. We discuss effects of marrow fat cells on bone metabolism, hematopoiesis, and inflammation. Special attention is given to CCL2- and COX-2-driven pathways and their potential as therapeutic targets for bone metastatic disease.

Cyclooxygenase-2 expression in non-metastatic triple-negative breast cancer patients

Triple-negative breast cancer (TNBC) is characterised by lack of estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor (HER)2/neu gene amplification. TNBC patients typically present at a younger age, with a larger average tumor size, higher grade and higher rates of lymph node positivity compared to patients with ER/PR-positive tumors. Cyclooxygenase (COX)-2 regulates the production of prostaglandins and is overexpressed in a variety of solid tumors. In breast cancer, the overexpression of COX-2 is associated with indicators of poor prognosis, such as lymph node metastasis, poor differentiation and large tumor size. Since both TNBC status and COX-2 overexpression are known poor prognostic markers in primary breast cancer, we hypothesized that the COX-2 protein is overexpressed in the primary tumors of TNBC patients. The purpose of this study was to determine whether there exists an association between TNBC status and COX-2 protein overexpression in primary breast cancer. We prospectively evaluated COX-2 expression levels in primary tumor samples obtained from 125 patients with stage I-III breast cancer treated between February, 2005 and October, 2007. Information on clinicopathological factors was obtained from a prospective database. Baseline tumor characteristics and patient demographics were compared between TNBC and non-TNBC patients using the Chi-square and Fisher's exact tests. In total, 60.8% of the patients were classified as having ER-positive tumors, 51.2% were PR-positive, 14.4% had HER-2/neu amplification and 28.0% were classified as TNBC. COX-2 overexpression was found in 33.0% of the patients. TNBC was associated with COX-2 overexpression (P=0.009), PR expression (P=0.048) and high tumor grade (P=0.001). After adjusting for age, menopausal status, body mass index (BMI), lymph node status and neoadjuvant chemotherapy (NACT), TNBC was an independent predictor of COX-2 overexpression (P=0.01). In conclusion, the association between TNBC and COX-2 overexpression in operable breast cancer supports further investigation into COX-2-targeted therapy for patients with TNBC.

COX2 expression in high-grade breast cancer: evidence for prognostic significance in the subset of triple-negative breast cancer patients

COX2 expression correlates with high-grade breast cancer, but the clinical significance and possible prognostic influence in these patients have not been studied in depth. Our goal was to evaluate the significance of COX2 expression in a group of patients with high-grade breast cancer. Three hundred and three patients (median age 55; age range 25-95 years) with high-grade breast cancer entered this retrospective study. Mean follow-up was 65.2 months (4-179 months). COX2 expression was studied by immunohistochemistry. The distribution of patients with high-grade tumors according to staining for COX2 was as follows: score 0-28/303 (9.3 %); score 1-101/303 (33.3 %); score 2-114/303 (37.6 %); score 3-60/303 (19.8 %). Patients with score 2 and 3 were classified as COX2 positive (174 of 303 patients (57.4 %). There was no correlation between any clinicopathological pattern, ER, PR, Her2 status and COX2 expression. In the group of patients with triple-negative breast cancer, the 5-year disease-free survival rate was 58.3 % for patients with COX2 expression compared with 83.9 % for patients without COX2 expression (P = 0.042). COX2 expression did not provide any prognostic significance for the other biological subtypes of breast cancer with high-grade histological features.

A COX-2 inhibitor enhances the antitumor effects of chemotherapy and radiotherapy for esophageal squamous cell carcinoma

Cyclooxygenase-2 (COX-2) is a key enzyme of prostaglandin (PG) synthesis that has been demonstrated to be overexpressed in several types of cancers. The function of COX-2 in tumor progression has been recently elucidated. In tumors in which COX-2 is overexpressed, the antitumor effects are suppressed. We examined the effects of celecoxib, a COX-2 inhibitor, in enhancing the antitumor effects of chemotherapy and radiotherapy for esophageal squamous cell carcinoma (ESCC) by reducing the COX-2 activity. We used the human esophageal squamous cell lines TE2 and T.Tn treated with celecoxib and 5-FU/radiation, after which cell viability assays were performed. Changes in the expressions of dihydropyrimidine dehydrogenase (DPD), orotate phosphoribosyl transferase (OPRT) mRNA and PGE2 were also measured. In addition, apoptotic changes, and the invasion and migration activity in both the celecoxib and 5-FU treated cells were evaluated. The experiments showed that T.Tn and TE2 proliferation was strongly inhibited by the combination of 5-FU/radiation and the COX-2 inhibitor. Inhibiting the COX-2 activity induced a reduction in PGE2 levels in TE2/T.Tn cells. Following treatment with the COX-2 inhibitor and 5-FU, the OPRT expression was upregulated and the DPD expression was downregulated in the resistant cells. In addition, the combination treatment with the COX-2 inhibitor and 5-FU markedly inhibited both the cell invasion and migration activity. Therefore, COX-2 inhibitors can be useful enhancers of antitumor drugs and radiotherapy for ESCC.

Does regional anaesthesia and analgesia or opioid analgesia influence recurrence after primary cancer surgery? An update of available evidence

Cancer continues to be a key cause of morbidity and mortality worldwide and its overall incidence continues to increase. Anaesthetists are increasingly faced with the challenge of managing cancer patients, for surgical resection to debulk or excise the primary tumour, or for surgical emergencies in patients on chemotherapy or for the analgesic management of disease- or treatment-related chronic pain. Metastatic recurrence is a concern. Surgery and a number of perioperative factors are suspected to accelerate tumour growth and potentially increase the risk of metastatic recurrence. Retrospective analyses have suggested an association between anaesthetic technique and cancer outcomes, and anaesthetists have sought to ameliorate the consequences of surgical trauma and minimise the impact of anaesthetic interventions. Just how anaesthesia and analgesia impact cancer recurrence and consequent survival is very topical, as understanding the potential mechanisms and interactions has an impact on the anaesthetist's ability to contribute to the successful outcome of oncological interventions. The outcome of ongoing, prospective, randomized trials are awaited with interest.

Premetastatic soil and prevention of breast cancer brain metastasis

BACKGROUND

As therapies for systemic cancer improve and patients survive longer, the risk for brain metastases increases. We evaluated whether immune mechanisms are involved in the development of brain metastasis.

METHODS

We conducted our studies using BALB/c mice bearing syngeneic 4T1 mammary adenocarcinoma cells in the mammary gland.

RESULTS

The brains of mice bearing 4T1 tumors at day 14 had no detectable metastatic tumor cells but presented with marked accumulation of bone marrow-derived CD11b(+)Gr1(+) myeloid cells, which express high levels of inflammatory chemokines S100A8 and S100A9. In vitro, S100A9 attracts 4T1 cells through Toll-like receptor 4 and CD11b(+)Gr1(+) myeloid cells through Toll-like receptor 4 and the receptor for advanced glycation end-products. Systemic treatment of 4T1-bearing mice with anti-Gr1 (RB6-8C5) monoclonal antibody reduces accumulation of CD11b(+)Gr1(+) myeloid cells in the day-14 premetastatic brain as well as subsequent brain metastasis of 4T1 cells detected on day 30. Furthermore, treatment of 4T1 tumor-bearing mice with the cyclooxygenase-2 inhibitor celecoxib or genetic disruption of cyclooxygenase-2 in 4T1 cells inhibits the inflammatory chemokines and infiltration of CD11b(+)Gr1(+) myeloid cells in the premetastatic brain and subsequent formation of brain metastasis.

CONCLUSIONS

Our results suggest that the primary tumor induces accumulation of CD11b(+)Gr1(+) myeloid cells in the brain to form "premetastatic soil" and inflammation mediators, such as S100A9, that attract additional myeloid cells as well as metastatic tumor cells. Celecoxib and anti-Gr1 treatment may be useful for blockade of these processes, thereby preventing brain metastasis in patients with breast cancer.

Elevated transcription of the gene QSOX1 encoding quiescin Q6 sulfhydryl oxidase 1 in breast cancer

The q arm of chromosome 1 is frequently amplified at the gene level in breast cancer. Since the significance of this is unclear we investigated whether 1q genes are overexpressed in this disease. The cDNA levels of 1q-located genes were analysed in a search for overexpressed genes. 26 genes mapping to the 1q arm show highly significant (P≤0.01) overexpression of transcripts in breast cancer compared to normal breast tissue. Amongst those showing the highest levels of overexpression in both expressed sequence tag (EST) and serial analysis of gene expression (SAGE) databases was enzyme quiescin Q6 sulfhydryl oxidase 1 (QSOX1). We investigated QSOX1 cDNA derived from T47D breast carcinoma cells by RT-PCR and 3′-RACE PCR and identified a novel extended form of QSOX1 transcript, containing a long 3′UTR, nearly double the size of the previously reported QSOX1 cDNA, and confirmed its 3′ end nucleotide sequence using RACE-PCR. We also used quantitative real-time PCR to analyse a panel of cDNAs derived from 50 clinically-graded normal and malignant breast tissue samples for the expression of QSOX1 mRNAs. QSOX1 transcription was elevated in an increasing proportion in the grade 2 and grade 3 tumours (graded according to the Nottingham prognostic index), with 10 of the 15 grade 3 tumours (67%) examined exceeding the normal range. There was a significant correlation between relative transcript level and clinical grade (P≤0.01) for all qPCR primer sets tested. QSOX1 mRNA levels, based on SAGE expression data, did not correlate with either Estrogen Receptor (ER) or Epidermal Growth Factor Receptor 2 (ErbB-2 or HER2/neu) expression. Our data indicate that QSOX1 is a potential new prognostic marker which may prove of use in the staging of breast tumours and the stratification of breast cancer patients.

Selection of metastatic breast cancer cells based on adaptability of their metabolic state

A small subpopulation of highly adaptable breast cancer cells within a vastly heterogeneous population drives cancer metastasis. Here we describe a function-based strategy for selecting rare cancer cells that are highly adaptable and drive malignancy. Although cancer cells are dependent on certain nutrients, e.g., glucose and glutamine, we hypothesized that the adaptable cancer cells that drive malignancy must possess an adaptable metabolic state and that such cells could be identified using a robust selection strategy. As expected, more than 99.99% of cells died upon glutamine withdrawal from the aggressive breast cancer cell line SUM149. The rare cells that survived and proliferated without glutamine were highly adaptable, as judged by additional robust adaptability assays involving prolonged cell culture without glucose or serum. We were successful in isolating rare metabolically plastic glutamine-independent (Gln-ind) variants from several aggressive breast cancer cell lines that we tested. The Gln-ind cells overexpressed cyclooxygenase-2, an indicator of tumor aggressiveness, and they were able to adjust their glutaminase level to suit glutamine availability. The Gln-ind cells were anchorage-independent, resistant to chemotherapeutic drugs doxorubicin and paclitaxel, and resistant to a high concentration of a COX-2 inhibitor celecoxib. The number of cells being able to adapt to non-availability of glutamine increased upon prior selection of cells for resistance to chemotherapy drugs or resistance to celecoxib, further supporting a linkage between cellular adaptability and therapeutic resistance. Gln-ind cells showed indications of oxidative stress, and they produced cadherin11 and vimentin, indicators of mesenchymal phenotype. Gln-ind cells were more tumorigenic and more metastatic in nude mice than the parental cell line as judged by incidence and time of occurrence. As we decreased the number of cancer cells in xenografts, lung metastasis and then primary tumor growth was impaired in mice injected with parental cell line, but not in mice injected with Gln-ind cells.

Disseminated tumor cells predict survival after neoadjuvant therapy in primary breast cancer

BACKGROUND

Tumor cells that disseminate to the bone marrow (disseminated tumor cells [DTCs]) have been identified in 30% of patients with stage I through II breast cancer (BC) and predict outcome. Neoadjuvant chemotherapy (NACT) is effective in reducing the size of primary tumors or eradicating lymph node metastases before surgery, but little is known regarding the presence or significance of DTCs after NACT.

METHODS

The authors evaluated DTCs in 95 patients with clinical stage I through III BC. Bone marrow samples were collected after completion of NACT at the time they underwent surgery for primary BC. DTCs were assessed using an anticytokeratin antibody cocktail. Primary tumor markers, the extent of lymph node (LN) involvement, they type of NACT administered, and response to NACT were compared with presence of DTCs. Chi-square and Fisher exact tests were used for statistical analyses.

RESULTS

The median patient age at diagnosis was 51 years, and the median follow-up was 24 months. Forty-six percent of patients had tumors classified as T1/T2, 20% had T3 tumors, 34.5% had T4 tumors, and 81% had lymph node metastasis before NACT. DTCs were identified in 26% of patients after NACT. No associations were observed between DTCs and primary tumor characteristics or LN involvement. A pathologic complete response was observed in 25 patients (26%) but was not predictive of DTCs after NACT (P = .83). DTCs after NACT predicted worse BC-specific survival (P < .02).

CONCLUSIONS

The presence of DTCs was an independent predictor of outcome after NACT. The current results indicated that monitoring hematogenous micrometastatic disease after NACT may be useful in selecting patients who might benefit from additional systemic adjuvant therapies.

microRNAs, Gap Junctional Intercellular Communication and Mesenchymal Stem Cells in Breast Cancer Metastasis

The failed outcome of autologous bone marrow transplantation for breast cancer opens the field for investigations. This is particularly important because the bone marrow could be a major source of cancer cells during tertiary metastasis. This review discusses subsets of breast cancer cells, including those that enter the bone marrow at an early period of disease development, perhaps prior to clinical detection. This population of cells evades chemotherapeutic damage even at high doses. An understanding of this population might be crucial for the success of bone marrow transplants for metastatic breast cancer and for the eradication of cancer cells in bone marrow. In vivo and in vitro studies have demonstrated gap junctional intercellular communication (GJIC) between bone marrow stroma and breast cancer cells. This review discusses GJIC in cancer metastasis, facilitating roles of mesenchymal stem cells (MSCs). In addition, the review addresses potential roles for miRNAs, including those already linked to cancer biology. The literature on MSCs is growing and their links to metastasis are beginning to be significant leads for the development of new drug targets for breast cancer. In summary, this review discusses interactions among GJIC, miRNAs and MSCs as future consideration for the development of cancer therapies.

TAK1-TAB2 signaling contributes to bone destruction by breast carcinoma cells

Advanced-stage breast cancers frequently metastasize to the bones and cause bone destruction, but the underlying mechanism is not fully understood. This study presents evidence that TGF-β-activated protein kinase 1 (TAK1) signaling in tumor cells promotes bone destruction by metastatic breast carcinoma cells, controlling expression of prometastatic factors including matrix metalloproteinase (MMP) 9 and COX2. Suppression of TAK1 signaling by dominant-negative TAK1 (dn-TAK1) in breast carcinoma MDA-MB-231 cells impairs bone colonization by carcinoma cells and bone osteolysis in the intracardiac injection model. Mechanistic studies showed that inhibition of TAK1 by dn-TAK1 or siRNA blocked expression of factors implicated in bone metastasis, such as MMP-9, COX2/PTGS2, parathyroid hormone-related protein (PTHrP) and interleukin 8 (IL-8), but did not affect activation of p38MAPK by TGF-β. TAK1 signaling is mediated by TAK1-binding partners TAB1, TAB2, and TAB3. Carcinoma cells express elevated mRNA levels of TAB2 and TAB3, whereas the TAB1 expression is noticeably low. Accordingly, depletion of TAB2 by siRNA reduced expression of MMP-9 and COX2. Together, these studies show that the TAK1-TAB2-TAB3 signaling axis is critical for carcinoma-induced bone lesions, mediating expression of proinvasive and osteolytic factors. These findings identify the TAK1-TAB2 axis as a potential therapeutic target in bone metastasis.

COX2 overexpression is a prognostic marker for Stage III breast cancer

To determine the significance of (Cyclooxygenase 2) COX2 for clinical outcome in breast cancer, we analyzed the correlation between COX2 overexpression and survival in 687 patients with invasive breast cancer. Cytoplasmic immunoreactivity of COX2 was determined as positive in 325 of 687 (47.3%) invasive breast cancers. COX2 positivity was significantly correlated with high histologic grade, negative estrogen receptor (ER), high Ki67, luminal B and triple-negative tumors, Bcl2 negativity, and p53 overexpression. In univariate analysis, COX2 overexpression resulted in significantly shorter relapse-free survival (RFS) [hazard ratio (HR) 1.487, 95% CI 1.035-2.110, P = 0.032]. Multivariate analysis revealed no significant association between COX2 overexpression and either overall survival (OS) or RFS. Kaplan-Meier analysis of the whole patient group showed significantly reduced RFS in patients with high COX2 expression, compared to those that did not overexpress COX2 (91 vs. 162 months, P = 0.031). Stratified subgroup analysis by TNM stage disclosed marked differences in OS and RFS rates in Stage III patients. We observed a significant association of COX2 overexpression with shorter RFS in the ER-negative subgroup of Stage III patients. The results show that COX2 overexpression is a significant unfavorable prognostic factor in Stage III breast cancer, and provide selective criteria for COX2 inhibitor combinations for invasive breast cancer therapy.

COX2 expression predicts resistance to chemoradiotherapy in esophageal squamous cell carcinoma

PURPOSE

The overexpression of cyclooxygenase (COX)2 is correlated with carcinogenesis, tumor progression, and prognosis, and increased COX2 expression is correlated with radiation resistance. However, no correlation between the COX2 expression and resistance to chemoradiotherapy for esophageal squamous cell carcinoma has been characterized. The purpose of the present study was to evaluate whether COX2 expression is an indicator of resistance to chemoradiotherapy in esophageal squamous cell carcinoma and the feasibility of COX2 as a biomarker for CRT.

METHODS

Fifty-eight patients who were diagnosed with esophageal squamous cell carcinoma from biopsy samples were enrolled in the present series. All patients underwent concurrent chemoradiotherapy in a neoadjuvant setting, followed by radical esophagectomy. COX2 expression was evaluated by immunohistochemical staining and statistically compared with the histopathologic findings in surgically resected specimens.

RESULTS

The rate of responders was 87% for weak expression of COX2, 62% for moderate expression, and 30% for strong expression, and there was a close correlation between COX2 expression and the response rate (Kendall's τb = 0.396, P = 0.001). In the univariate analysis, negative or weak expression of COX2 was found to correlate significantly with CRT response (odds ratio, 6.296; 95% confidence interval (CI), 1.58-25.096; P = 0.010). In the multivariate analysis, weak expression of COX2 (30% or less) was found to be an independent prognostic factor (odds ratio, 6.534; 95% CI, 1.535-27.803; P = 0.011).

CONCLUSIONS

The COX2 expression predicts resistance to chemoradiotherapy in esophageal squamous cell carcinoma, and it also is a feasible biomarker for evaluating the CRT response.

Overexpression of COX-2 in celecoxib-resistant breast cancer cell lines

BACKGROUND

Cyclooxygenase-2 (COX-2) plays a key role in breast cancer progression and metastasis. Effective therapeutic targeting of COX-2 would require the knowledge of whether a tumor is addicted to COX-2, and if we can counter the potential resistance to anti-COX-2 therapy. Herein we tested the hypothesis that celecoxib-resistance involves selection of cancer cells that overexpress COX-2.

MATERIALS AND METHODS

We selected celecoxib-resistant (CER) variants from two metastatic cell lines, SUM149 inflammatory breast cancer (IBC) cell line and MDA-MB-231-BSC60 cell line, by culturing them in the presence of celecoxib. We measured the relative levels of COX-2 protein and its network components Bcl-2, Bcl-xL, and Bax in the parental cell lines and their CER variants by Western blotting. To determine whether celecoxib resistance would increase tumorigenicity, we performed an in vitro clonogenicity assay. We determined the statistical significance of differences between the groups using the two-sample t-test.

RESULTS

Both the celecoxib-resistant cell lines SUM149-CER and BSC60-CER produced significantly higher levels of COX-2 protein than their parental counterparts (P < 0.05). The CER variants produced a reduced level of pro-apoptosis protein Bax (both cell lines) and increased levels of anti-apoptosis proteins Bcl-2 (BSC60) or Bcl-xL (SUM149). Importantly, the CER variants had significantly higher clonogenicity than their parental cell lines (P < 0.05). The siRNA-mediated COX-2 knockdown in SUM149-CER cell line resulted in a significant decrease in clonogenicity and in Bcl-xL and Bcl-2 protein levels, thus supporting our hypothesis.

CONCLUSION

Celecoxib-resistant variant cells present in breast cancer cell lines overexpress COX-2, which is robustly linked with survival pathways and clonogenicity. Since COX-2 is important in the variant cancer cells of aggressive nature, it represents a good therapeutic target.

A multicenter randomized phase II study of sequential epirubicin/cyclophosphamide followed by docetaxel with or without celecoxib or trastuzumab according to HER2 status, as primary chemotherapy for localized invasive breast cancer patients

To assess anti-tumor activity of sequential epirubicin/cyclophosphamide followed by docetaxel with the randomized addition of celecoxib in HER2 negative patients or trastuzumab in HER2 positive patients. From May 2004 till October 2007, 340 patients with stage II and III breast adenocarcinoma, ineligible for breast conserving surgery, received eight sequential three weekly cycles of EC-D [epirubicin (75 mg/m(2))-cyclophosphamide (750 mg/m(2)) for four cycles followed by docetaxel (100 mg/m(2)) for four cycles]. HER2-negative patients (N = 220) were randomized to receive concomitantly with docetaxel celecoxib 800 mg/day during cycles 5-8 or no additional treatment, while HER2-positive patients confirmed by FISH (N = 120) were randomized to trastuzumab concomitant to docetaxel (8 mg/kg then 6 mg/kg IV every 3 weeks) or no additional preoperative treatment. In the HER2 negative group, pCR (grade 1 and 2 of Chevallier's classification) was observed in 11.5 and 13% of patients treated without and with neoadjuvant Celecoxib, respectively. In the HER2 positive group, pCR rate reached 26% in those who received neoadjuvant trastuzumab versus 19% in the others. There was no unexpected toxicity, no cardiac toxicity, and no toxic death. Triple negative breast cancers experience the highest pCR rate of 30%. Celecoxib is not likely to improve pCR rates in addition to EC-D in patients with HER2-negative tumor. In HER2-positive tumor patients, trastuzumab added to ECD leads to increased pCR rates. It was the only combination to deserve further study according to the two-stage Fleming's design used in this trial.

Role of COX-2 in tumorospheres derived from a breast cancer cell line

BACKGROUND

Cyclooxygenase-2 (COX-2) expression in primary breast cancer predicts tumor cell dissemination to bone marrow, which is a risk factor for recurrence and distant metastasis. "Stem-like" phenotype may be important in cancer metastasis.

METHODS

To investigate the role of COX-2 protein in breast cancer stem-like cells, we analyzed it by co-immunofluorescence in tumorospheres derived from the MCF7 estrogen receptor-positive breast cancer cell line. To evaluate COX-2 function we utilized a COX-2 inhibitor in a clonogenicity assay performed with tumorospheres-derived cells.

RESULTS

We detected rare cells in tumorospheres (one cell per tumorosphere) with very high COX-2 expression (COX-2(high)). COX-2 transfected MCF7 cells were able to generate long-term tumorospheres culture, even though transfection efficiency was only one in a million cells. We detected expression of OCT4 in some COX-2(high) cells, supporting the hypothesis that these cells could be cancer stem-like cells. It is important that COX-2(high) cells showed less expression of Ki-67 than did neighboring cells, indicating that COX-2(high) cells may be progenitors of tumorospheres. Celecoxib inhibited the growth of tumorosphere cultures and the ability of tumorosphere-derived cells to form colonies in vitro, indicating an active role of COX-2 in these processes. However, 2 μM celecoxib failed to eradicate tumorosphere-initiating cells. Finally, we detected rare COX-2(high) cells among SUM149 inflammatory breast cancer cells growing on plastic in serum-containing medium; the SUM149 cell line produces a very high level of COX-2 protein.

CONCLUSION

Our results support a role for COX-2 in stem-like breast cancer cells and suggest a mechanism behind a role for COX-2 in disseminated tumor cells, which are known to exhibit characteristic biomarkers and functional properties of stem-like cells.

Reduced risk of bone metastasis for patients with breast cancer who use COX-2 inhibitors

PURPOSE

We hypothesize that the use of cyclooxygenase (COX)-2 inhibitors in early disease phases could protect against the development of bony metastases.

PATIENTS AND METHODS

The medical charts of patients with stage II-III breast cancer diagnosed between 1999 and 2005 were reviewed. Patients were subdivided according to the use of COX-2 inhibitors after the diagnosis and for > or = 6 months. Bivariate analyses were undertaken, and statistically significant variables were included in a multivariate logistic regression model.

RESULTS

Eleven percent of patients (74 of 644) who did not use COX-2 inhibitors developed bone metastases compared with 2% (1 of 48) of those who did use COX-2 inhibitors (Fisher exact test, P = .05). Significant predictors for bone metastases in a multivariate logistic regression model included: > or = 3 positive nodes (odds ratio [OR], 3.26 [95% CI, 1.79-5.93]; P < .001), stage IIB-IIIC disease (OR, 3.89 [95% CI: 1.74-8.69]; P = .001) and use of COX-2 inhibitors (OR, 0.12 [95% CI, 0.02-0.88]; P = .037). Adjusting for TNM stage, of the 327 patients with stages IIB-IIIC disease, 22% (63 of 293) had bone metastases in the non-COX-2 group versus 3% (1 of 34) in the COX-2 inhibitors consumers (Fisher exact test, P = .006). In this high-risk group of patients, the calculated OR associated with COX-2 inhibitors was 0.10 (95% CI, 0.01-0.78).

CONCLUSION

The use of COX-2 inhibitors could reduce the risk of bone metastases in stage II-III breast cancer.

DNA damage drives an activin a-dependent induction of cyclooxygenase-2 in premalignant cells and lesions

Cyclooxygenase-2 (COX-2) catalyzes the rate-limiting step in the synthesis of prostaglandins. Its overexpression induces numerous tumor-promoting phenotypes and is associated with cancer metastasis and poor clinical outcome. Although COX-2 inhibitors are promising chemotherapeutic and chemopreventative agents for cancer, the risk of significant cardiovascular and gastrointestinal complications currently outweighs their potential benefits. Systemic complications of COX-2 inhibition could be avoided by specifically decreasing COX-2 expression in epithelial cells. To that end, we have investigated the signal transduction pathway regulating the COX-2 expression in response to DNA damage in breast epithelial cells. In variant human mammary epithelial cells that have silenced p16 (vHMEC), double-strand DNA damage or telomere malfunction results in a p53- and activin A-dependent induction of COX-2 and continued proliferation. In contrast, telomere malfunction in HMEC with an intact p16/Rb pathway induces cell cycle arrest. Importantly, in ductal carcinoma in situ lesions, high COX-2 expression is associated with high gammaH2AX, TRF2, activin A, and telomere malfunction. These data show that DNA damage and telomere malfunction can have both cell-autonomous and cell-nonautonomous consequences and can provide a novel mechanism for the propagation of tumorigenesis.