NRP2 transcriptionally regulates its downstream effector WDFY1

Neuropilins (NRPs) are cell surface glycoproteins that often act as co-receptors for plexins and VEGF family receptors. Neuropilin-2 (NRP2), a family member of NRPs, was shown to regulate autophagy and endocytic trafficking in cancer cells, a function distinctly different from its role as a co-receptor. WD Repeat and FYVE domain containing 1 (WDFY1)–protein acts downstream of NRP2 for this function. Our results indicated that NRP2 maintains an optimum concentration of WDFY1 by negatively regulating its expression. Since increased expression of WDFY1 reduces the endocytic activity, maintenance of WDFY1 level is crucial in metastatic cancer cells to sustain high endocytic activity, essential for promotion of oncogenic activation and cancer cell survival. Here, we have delineated the underlying molecular mechanism of WDFY1 synthesis by NRP2. Our results indicated that NRP2 inhibits WDFY1 transcription by preventing the nuclear localization of a transcription factor, Fetal ALZ50-reactive clone 1 (FAC1). Our finding is novel as transcriptional regulation of a gene by NRP2 axis has not been reported previously. Regulation of WDFY1 transcription by NRP2 axis is a critical event in maintaining metastatic phenotype in cancer cells. Thus, inhibiting NRP2 or hyper-activating WDFY1 can be an effective strategy to induce cell death in metastatic cancer.

Impact of reassessment of colonic hyperplastic polyps by expert GI pathologists

BACKGROUND

Recommended follow-up intervals after endoscopic removal of hyperplastic polyps (HP) and sessile serrated adenomas (SSA) differ because of assumed differences in biological behaviour. However, histopathologic differentiation is difficult, with higher SSA rates reported from specialist GI histopathologists.

OBJECTIVE

The objective of this study was to clarify the relevance of histologic reassessment of HP.

DESIGN AND SETTING

From a prospective screening colonoscopy study relevant serrated lesions (excluding distal small HP ≤5 mm) diagnosed by private practice pathologists were reassessed by four specialized GI pathologists

PATIENTS

One thousand sixty-nine screening colonoscopies were performed in patients.

MAIN OUTCOME MEASUREMENTS

In terms of main outcome measurements, there is a likelihood of changes of the HP diagnosis on reassessment, as well as interrater variability.

RESULTS

SSA were initially diagnosed in 7 cases (0.7%) and relevant HP in 83 (7.8%; 101 lesions). Of the latter, the chance of a change in diagnosis from HP to SSA by any of the four specialist histopathologists was higher for larger (>5 mm) and right-sided lesions (19.1 vs 1.3%, OR 18.4, p = 0.04) including a higher likelihood to change recommended follow-up intervals (32.1 vs 3.3%, p < 0.01). However, follow-up intervals were determined by concomitant adenomas in 41%. Interrater variability was also higher for these lesions (p = 0.04), with an overall kappa value of 0.48. However, this issue related to only 1.2% of the 1069 study cases.

LIMITATION

The limitations this study are the limited case number as well as limited retrospective assessment.

CONCLUSIONS

Right-sided HP >5 mm had a higher chance of change in diagnosis to SSA; therefore, they should probably be treated like adenomas and be removed. However, reliable data for recommendations on follow-up intervals of HP or SSA will require follow-up studies.

Low Cancer Stem Cell Marker Expression and Low Hypoxia Identify Good Prognosis Subgroups in HPV(-) HNSCC after Postoperative Radiochemotherapy: A Multicenter Study of the DKTK-ROG

PURPOSE

To investigate the impact of hypoxia-induced gene expression and cancer stem cell (CSC) marker expression on outcome of postoperative cisplatin-based radiochemotherapy (PORT-C) in patients with locally advanced head and neck squamous cell carcinoma (HNSCC).

EXPERIMENTAL DESIGN

Expression of the CSC markers CD44, MET, and SLC3A2, and hypoxia gene signatures were analyzed in the resected primary tumors using RT-PCR and nanoString technology in a multicenter retrospective cohort of 195 patients. CD44 protein expression was further analyzed in tissue microarrays. Primary endpoint was locoregional tumor control.

RESULTS

Univariate analysis showed that hypoxia-induced gene expression was significantly associated with a high risk of locoregional recurrence using the 15-gene signature (P = 0.010) or the 26-gene signature (P = 0.002). In multivariate analyses, in patients with HPV16 DNA-negative but not with HPV16 DNA-positive tumors the effect of hypoxia-induced genes on locoregional control was apparent (15-gene signature: HR 4.54, P = 0.006; 26-gene signature: HR 10.27, P = 0.024). Furthermore, MET, SLC3A2, CD44, and CD44 protein showed an association with locoregional tumor control in multivariate analyses (MET: HR 3.71, P = 0.016; SLC3A2: HR 8.54, P = 0.037; CD44: HR 3.36, P = 0.054; CD44 protein n/a because of no event in the CD44-negative group) in the HPV16 DNA-negative subgroup.

CONCLUSIONS

We have shown for the first time that high hypoxia-induced gene expression and high CSC marker expression levels correlate with tumor recurrence after PORT-C in patients with HPV16 DNA-negative HNSCC. After validation in a currently ongoing prospective trial, these parameters may help to further stratify patients for individualized treatment de-escalation or intensification strategies. Clin Cancer Res; 22(11); 2639-49. ©2016 AACR.

Is the Post-Radical Prostatectomy Gleason Score a Valid Predictor of Mortality after Neoadjuvant Hormonal Treatment?

PURPOSE

To evaluate the validity of the Gleason score after neoadjuvant hormonal treatment as predictor of disease-specific mortality after radical prostatectomy.

PATIENTS AND METHODS

A total of 2,880 patients with a complete data set and a mean follow-up of 10.3 years were studied; 425 of them (15%) had a history of hormonal treatment prior to surgery. The cumulative incidence of deaths from prostate cancer was determined by univariate and multivariate competing risk analysis. Cox proportional hazard models for competing risks were used to study combined effects of the variables on prostate cancer-specific mortality.

RESULTS

A higher portion of specimens with a history of neoadjuvant hormonal treatment were assigned Gleason scores of 8-10 (28 vs. 17%, p < 0.0001). The mortality curves in the Gleason score strata <8 vs. 8-10 were at large congruent in patients with and without neoadjuvant hormonal treatment. In patients with neoadjuvant hormonal treatment, a Gleason score of 8-10 was an independent predictor of prostate cancer-specific mortality; the hazard ratio was, however, somewhat lower than in patients without neoadjuvant hormonal treatment.

CONCLUSION

This study suggests that the prognostic value of the post-radical prostatectomy Gleason score is not meaningfully jeopardized by heterogeneous neoadjuvant hormonal treatment in a routine clinical setting.

[The metastatic niche. Mechanisms and prognostic implications]

Disseminated tumor cells require a special microenvironment to form metastases. This metastatic niche is organ specific and forms prior to the establishment of visible metastases. The niche is characterized by vascular remodeling and bone marrow-derived cells which have migrated into it. Studies by other groups and our own results have already shown that intranodal lymphangiogenesis is an important prerequisite for regional lymph node metastases in rectal cancer patients, and can be used as a prognostic marker for progression-free survival. Niche cells such as endothelia secrete factors that attract tumor and bone marrow-derived cells. CXCL12 is one of these factors. CXCL12 activates the CXCR4 chemokine axis and induces migration along its gradient. Several factors, such as hypoxia, have been described to regulate CXCR4 function and surface expression on tumor cells. Low molecular weight agents have been used to block CXCR4 activation. This review focuses on the function and regulation of CXCR4 and its ligand CXCL12 in metastases formation. It also discusses potential options for therapeutic blockage.

Abstract 3304: Role of Vascular Endothelial Growth Factor C in promoting radioresistance of prostate cancer

Radiotherapy is an important treatment regimen for prostate cancer. We have shown that the lymphangiogenic growth factor, Vascular Endothelial Growth Factor C (VEGF-C), induces docetaxel resistance and autophagy in prostate cancer (Muders et al., Cancer Res 2009 and Stanton et al., Cancer Res 2013). In this study we have evaluated the role of VEGF-C and VEGF-C induced autophagy in radioresistance of prostate cancer using cell culture experiments and human tissue samples.

The human prostate carcinoma cell lines PC-3, LNCaP and DU145 were used in these cell culture experiments. Clonogenic survival of prostate cancer cells, after RNA interference (RNAi) of VEGF-C, autophagy related gene 5 (ATG5), and after addition of recombinant human VEGF-C following irradiation therapy, was evaluated. Autophagic flux was tested after ionizing irradiation using a Light-Chain-3 II immunoblot. To confirm our in vitro findings, human tissues of patients who underwent radical prostatectomy and adjuvant radiotherapy at Mayo Clinic were evaluated for VEGF-C expression. The quantity and intensity of VEGF-C staining was evaluated by two pathologists independently and correlated with biochemical relapse free survival (BRFS). The follow-up time is up to 23 years after radiotherapy. Multivariate Cox analysis was performed.

VEGF-C levels correlated with a significantly higher radioresistance in colony formation assays and human tissue samples by multivariate analysis. The risk of biochemical recurrence increased 2.8 fold (95% confidence interval: 1.109 to 7.237; p = 0.03) when VEGF-C was highly expressed in prostatectomy patients with adjuvant radiotherapy. In line with our studies on autophagy in VEGF-C mediated docetaxel resistance of prostate cancer, autophagic flux was reduced after VEGF-C depletion during radiation. Interestingly, RNAi for ATG5 showed no effect on radiosensitivity which suggests that the decrease in autophagic flux after VEGF-C depletion is not responsible for the increased radiosensitivity.

We conclude that VEGF-C is an important mediator of radiotherapy resistance in prostate cancer. In contrast to our published results on chemotherapy resistance, VEGF-C induced autophagy appears to be less important for resistance against ionizing radiation. Other VEGF-C dependent mechanisms for therapy resistance are under investigation.

Citation Format: Steffi Haberlau, Pia Hönscheid, Rafael E. Jimenez, Gustavo B. Baretton, Donald J. Tindall, Mechthild Krause, Kaustubh Datta, Michael H. Muders. Role of Vascular Endothelial Growth Factor C in promoting radioresistance of prostate cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3304. doi:10.1158/1538-7445.AM2015-3304

Decreased Overall and Bladder Cancer-Specific Mortality with Adjuvant Chemotherapy After Radical Cystectomy: Multivariable Competing Risk Analysis

Adding chemotherapy to radical cystectomy (RC) may improve outcome. Neoadjuvant treatment is advocated by guidelines based on meta-analysis data but is severely underused in clinical practice. Adjuvant treatment of patients at risk could be an alternative. We analyzed a sample of 798 patients who underwent RC between 1993 and 2011 for high-risk superficial or muscle-invasive urothelial or undifferentiated bladder cancer, of which 23% received adjuvant cisplatin-based chemotherapy and %5 received neoadjuvant chemotherapy. The use of adjuvant chemotherapy was an independent predictor of decreased overall mortality (hazard ratio [HR]: 0.50; 95% confidence interval [CI], 0.38-0.66; p<0.0001) and bladder cancer-specific mortality (HR: 0.71; 95% CI, 0.52-0.97; p=0.0321), but it was not associated with competing mortality. Similar figures were obtained when analyzing the number of cisplatin-containing cycles administered or when restricting the analysis to patients with lymph node-positive or extravesical but lymph node-negative disease, suggesting a mortality-reducing treatment effect after adjusting for several patient- and tumor-related confounders. Future trials should directly compare the concepts of neoadjuvant and adjuvant application of chemotherapy in candidates for RC.

PATIENT SUMMARY

Adjuvant chemotherapy may decrease overall and bladder cancer-specific mortality after radical cystectomy (RC). Future trials should directly compare the concepts of neoadjuvant and adjuvant application of chemotherapy in candidates for RC.

WNT5A has anti-prostate cancer effects in vitro and reduces tumor growth in the skeleton in vivo

Prostate cancer is the most frequent malignancy in men, and a major cause of prostate cancer-related death is attributable to bone metastases. WNT5A is known to influence the clinical outcome of various cancer types, including prostate cancer, but the exact mechanisms remain unknown. The goal of this study was to assess the relevance of WNT5A for the development and progression of prostate cancer. WNT5A expression was determined in a cDNA and tissue microarray of primary tumor samples in well-defined cohorts of patients with prostate cancer. Compared with benign prostate tissue, the expression of WNT5A and its receptor Frizzled-5 was higher in prostate cancer, and patients with a WNT5A expression above the median had a higher probability of survival after 10 years. Using different osteotropic human prostate cancer cell lines, the influence of WNT5A overexpression and knock-down on proliferation, migration, and apoptosis was assessed. In vitro, WNT5A overexpression induced prostate cancer cell apoptosis and reduced proliferation and migration, whereas WNT5A knock-down showed opposite effects. In vivo, different xenograft models were used to determine the effects of WNT5A on tumor growth. Local tumor growth and tumor growth in the bone microenvironment was considerably diminished after WNT5A overexpression in PC3 cells. WNT5A exhibits antitumor effects in prostate cancer cells and may be suitable as a prognostic marker and therapeutic target for prostate cancer and associated skeletal metastases.

Lee mortality index as comorbidity measure in patients undergoing radical cystectomy

To investigate the recently described Lee mortality index as predictor of mortality after radical cystectomy.

A total of 735 patients who underwent radical cystectomy for bladder cancer between 1993 and 2010 were studied. Median patient age was 67 years and the median follow-up was 7.8 years (censored patients). The Lee mortality index was assigned based on data derived from patient history, preoperative cardiopulmonary risk assessment and discharge records. The age-adjusted Charlson score and preoperative cardiopulmonary risk assessment classifications were used for comparison. Competing risk analysis and Cox proportional hazard models for competing risks were used for the statistical analysis.

The Lee mortality index predicted competing mortality in a dose–response relationship with somewhat lower 10-year mortality rates than predicted (p = 0.0120). Beside the age-adjusted Charlson score, the Lee mortality index was an independent predictor of overall mortality (hazard ratio per unit increase 1.06, p = 0.0415) and replaced the age-adjusted Charlson score as predictor of competing mortality (hazard ratio (HR) per unit increase 1.27, p < 0.0001). The American Society of Anesthesiologists (ASA) physical status classification was also an independent predictor of overall (HR for ASA 3–4 versus 1–2: 1.53, p = 0.0002) and competing mortality (HR for ASA 3–4 versus 1–2: 1.62, p = 0.0044).

The Lee mortality index is a promising and easily applicable tool to predict competing mortality after radical cystectomy. It is at least equal to the age-adjusted Charlson score and may be supplemented by information provided by the ASA classification.

RNA quality in fresh-frozen gastrointestinal tumor specimens-experiences from the tumor and healthy tissue bank TU Dresden

The term "pre-analytics" summarizes all procedures concerned with specimen collection or processing as well as logistical aspects like transport or storage of tissue specimens. All or these variables as well as tissue-specific characteristics affect sample quality. While certain parameters like warm ischemia or tissue-specific characteristics cannot be changed, other parameters can be assessed and optimized. The aim of this study was to determine RNA quality by assessing the RIN values of specimens from different organs and to assess the influence of vacuum preservation. Samples from the GI tract, in general, appear to have lower RNA quality when compared to samples from other organ sites. This may be due to the digestive enzymes or bacterial colonization. Processing time in pathology does not significantly influence RNA quality. Tissue preservation with a vacuum sealer leads to preserved RNA quality over an extended period of time and offers a feasible alternative to minimize the influence of transport time into pathology.

HPV16 DNA status is a strong prognosticator of loco-regional control after postoperative radiochemotherapy of locally advanced oropharyngeal carcinoma: results from a multicentre explorative study of the German Cancer Consortium Radiation Oncology Group (DKTK-ROG)

OBJECTIVE

To investigate the impact of HPV status in patients with locally advanced head and neck squamous cell carcinoma (HNSCC), who received surgery and cisplatin-based postoperative radiochemotherapy.

MATERIALS AND METHODS

For 221 patients with locally advanced squamous cell carcinoma of the hypopharynx, oropharynx or oral cavity treated at the 8 partner sites of the German Cancer Consortium, the impact of HPV DNA, p16 overexpression and p53 expression on outcome were retrospectively analysed. The primary endpoint was loco-regional tumour control; secondary endpoints were distant metastases and overall survival.

RESULTS

In the total patient population, univariate analyses revealed a significant impact of HPV16 DNA positivity, p16 overexpression, p53 positivity and tumour site on loco-regional tumour control. Multivariate analysis stratified for tumour site showed that positive HPV 16 DNA status correlated with loco-regional tumour control in patients with oropharyngeal carcinoma (p=0.02) but not in the oral cavity carcinoma group. Multivariate evaluation of the secondary endpoints in the total population revealed a significant association of HPV16 DNA positivity with overall survival (p<0.01) but not with distant metastases.

CONCLUSIONS

HPV16 DNA status appears to be a strong prognosticator of loco-regional tumour control after postoperative cisplatin-based radiochemotherapy of locally advanced oropharyngeal carcinoma and is now being explored in a prospective validation trial.

Lack of ephrin receptor A1 is a favorable independent prognostic factor in clear cell renal cell carcinoma

The EPH receptor tyrosine kinases and their cell-bound ligands, the ephrins, have been shown to be associated with cancer development and progression. In this study, mRNA and protein expression of the receptors EPHA1 and EPHA2 as well as of their ligand EFNA1 and their prognostic relevance in clear cell renal cell carcinoma was evaluated. Gene expression was measured in 75 cryo-preserved primary tumors and matched non-malignant renal specimens by quantitative PCR. Protein expression was analyzed by immunohistochemistry on tissue microarrays comprising non-malignant, primary tumors and metastatic renal tissues of 241 patients. Gene and protein expression of all three factors was altered in tumor specimens with EPHA1 and EPHA2 being generally diminished in tumors compared to normal renal tissue, whereas EFNA1 was commonly elevated. A positive EPHA1 and EPHA2 protein staining as well as a low EFNA1 protein level were significantly linked to more aggressive tumor features, but only a positive EPHA1 immunoreactivity was significantly associated with poor survival. In subgroup analyses, EPHA1 and EPHA2 protein levels were significantly higher in metastatic than in primary lesions. Patients with EPHA1/EPHA2-positive tumors or with tumors with positive EPHA1 and low EFNA1 immunoreactivity had the shortest survival rates compared to the respective other combinations. In a multivariate model, EPHA1 was an independent prognostic marker for different survival endpoints. In conclusion, an impaired EPH-ephrin signaling could contribute to the pathogenesis and progression of clear cell renal cell carcinoma.

Neuropilin-2 and its ligand VEGF-C predict treatment response after transurethral resection and radiochemotherapy in bladder cancer patients

The standard treatment for invasive bladder cancer is radical cystectomy. In selected patients, bladder-sparing therapy can be performed by transurethral resection (TURBT) and radio-chemotherapy (RCT) or radiotherapy (RT). Our published in vitro data suggest that the Neuropilin-2 (NRP2)/VEGF-C axis plays a role in therapy resistance. Therefore, we studied the prognostic impact of NRP2 and VEGF-C in 247 bladder cancer patients (cN0M0) treated with TURBT and RCT (n = 198) or RT (n = 49) and a follow-up time up to 15 years. A tissue microarray was analyzed by immunohistochemistry. NRP2 expression emerged as a prognostic factor in overall survival (OS; HR: 3.42; 95% CI: 1.48 - 7.86; p = 0.004) and was associated with a 3.85-fold increased risk of an early cancer specific death (95% CI: 0.91 - 16.24; p = 0.066) in multivariate analyses. Cancer specific survival (CSS) dropped from 166 months to 85 months when NRP2 was highly expressed (p = 0.037). Patients with high VEGF-C expression have a 2.29-fold increased risk of shorter CSS (95% CI: 1.03-5.35; p = 0.043) in univariate analysis. CSS dropped from 170 months to 88 months in the case of high VEGF-C expression (p = 0.041). Additionally, NRP2 and VEGF-C coexpression is a prognostic marker for OS in multivariate models (HR: 7.54; 95% CI: 1.57-36.23; p = 0.012). Stratification for muscle invasiveness (T1 vs. T2-T4) confirmed the prognostic role of NRP2 and NRP2/VEGF-C co-expression in patients with T2-T4 but also with high risk T1 disease. In conclusion, immunohistochemistry for NRP2 and VEGF-C has been determined to predict therapy outcome in bladder cancer patients prior to TURBT and RCT.

An exotic cause of exudative enteropathy

PATIENT

Male, 50 FINAL DIAGNOSIS: Exudative enteropathy Symptoms: Abdominal pain • diarrhea • fever • hyponatremia • lymphadenopathy • weight loss

MEDICATION

- Clinical Procedure: - Specialty: -

OBJECTIVE

Unusual clinical course.

BACKGROUND

Protein-losing enteropathy is a rare cause of hypoproteinemia. Erosive and non-erosive gastrointestinal diseases as well as vascular disorders that result in increased central venous pressure or mesenteric lymphatic obstruction may result in protein loss via the gastrointestinal tract.

CASE REPORT

We present the case of a 50-year-old man with protein-losing enteropathy, who had profuse diarrhea, abdominal pain, lymphadenopathy, fever, and a weight loss of 10 kg in the preceding 2 months. Extensive work-up revealed infection with Giardia lamblia. We review clinical signs and symptoms, laboratory findings, and imaging studies, and discuss potential pitfalls in establishing the diagnosis.

CONCLUSIONS

To the best of our knowledge, this represents one of the few published cases of intestinal giardiasis as a cause of protein-losing enteropathy in an immunocompetent adult. The diagnosis of lambliasis should be based on a combination of stool cultures and serum serology, and in cases of high clinical suspicion, an endoscopy and biopsy of the upper GI tract is recommended.

A combined index to classify prognostic comorbidity in candidates for radical prostatectomy

BACKGROUND

In patients with early prostate cancer, stratification by comorbidity could be of importance in clinical decision making as well as in characterizing patients enrolled into clinical trials. In this study, we investigated several comorbidity classifications as predictors of overall mortality after radical prostatectomy, searching for measures providing complementary prognostic information which could be combined into a single score.

METHODS

The study sample consisted of 2205 consecutive patients selected for radical prostatectomy with a mean age of 64 years and a mean follow-up of 9.2 years (median: 8.6). Seventy-four patients with incomplete tumor-related data were excluded. In addition to age and tumor-related parameters, six comorbidity classifications and the body mass index were assessed as possible predictors of overall mortality. Kaplan-Meier curves and Mantel-Haenszel hazard ratios were used for univariate analysis. The impact of different causes of death was analyzed by competing risk analysis. Cox proportional hazard models were calculated to analyze combined effects of variables.

RESULTS

Age, Gleason score, tumor stage, Charlson score, American Society of Anesthesiologists (ASA) physical status class and body mass index were identified a significant predictors of overall mortality in the multivariate analysis regardless whether two-sided and three-sided stratifications were used. Competing risk analysis revealed that the excess mortality in patients with a body mass index of 30 kg/m2 or higher was attributable to competing mortality including second cancers, but not to prostate cancer mortality.

CONCLUSION

Stratifying patients by a combined consideration of the comorbidity measures Charlson score, ASA classification and body mass index may assist clinical decision making in elderly candidates for radical prostatectomy.

Down-regulation of heat shock protein HSP90ab1 in radiation-damaged lung cells other than mast cells

Ionizing radiation (IR) leads to fibrosing alveolitis (FA) after a lag period of several weeks to months. In a rat model, FA starts at 8 weeks after IR. Before that, at 5.5 weeks after IR, the transcription factors Sp1 (stimulating protein 1) and AP-1 (activator protein 1) are inactivated. To find genes/proteins that were down-regulated at that time, differentially expressed genes were identified in a subtractive cDNA library and verified by quantitative RT-PCR (reverse transcriptase polymerase chain reaction), western blotting and immunohistochemistry (IH). The mRNA of the molecular chaperone HSP90AB1 (heat shock protein 90 kDa alpha, class B member 1) was down-regulated 5.5 weeks after IR. Later, when FA manifested, HSP90ab1 protein was down-regulated by more than 90% in lung cells with the exception of mast cells. In most mast cells of the normal lung, both HSP90ab1 and HSP70, another major HSP, show a very low level of expression. HSP70 was massively up-regulated in all mast cells three months after irradiation whereas HSP90AB1 was up-regulated only in a portion of mast cells. The strong changes in the expression of central molecular chaperones may contribute to the well-known disturbance of cellular functions in radiation-damaged lung tissue.

Dickkopf-1 is regulated by the mevalonate pathway in breast cancer

Introduction

Amino-bisphosphonates and statins inhibit the mevalonate pathway, and may exert anti-tumor effects. The Wnt inhibitor dickkopf-1 (DKK-1) promotes osteolytic bone lesions by inhibiting osteoblast functions and has been implicated as an adverse marker in multiple cancers. We assessed the effects of mevalonate pathway inhibition on DKK-1 expression in osteotropic breast cancer.

Methods

Regulation of DKK-1 by bisphosphonates and statins was assessed in human breast cancer cell lines, and the role of the mevalonate pathway and downstream targets was analyzed. Moreover, the potential of breast cancer cells to modulate osteoblastogenesis via DKK-1 was studied in mC2C12 cells. Clinical relevance was validated by analyzing DKK-1 expression in the tissue and serum of women with breast cancer exposed to bisphosphonates.

Results

DKK-1 was highly expressed in receptor-negative breast cancer cell lines. Patients with receptor-negative tumors displayed elevated levels of DKK-1 at the tissue and serum level compared to healthy controls. Zoledronic acid and atorvastatin potently suppressed DKK-1 in vitro by inhibiting geranylgeranylation of CDC42 and Rho. Regulation of DKK-1 was strongest in osteolytic breast cancer cell lines with abundant DKK-1 expression. Suppression of DKK-1 inhibited the ability of breast cancer cells to block WNT3A-induced production of alkaline phosphates and bone-protective osteoprotegerin in preosteoblastic C2C12 cells. In line with the in vitro data, treatment of breast cancer patients with zoledronic acid decreased DKK-1 levels by a mean of 60% after 12 months of treatment.

Conclusion

DKK-1 is a novel target of the mevalonate pathway that is suppressed by zoledronic acid and atorvastatin in breast cancer.

Abstract P6-06-48: Breast cancer subtypes and metastatic pattern at the Regional Breast Center Dresden

Background: Breast cancer is classified into the subtypes luminal A, luminal B (HER2 positive or negative), HER2 enriched (not luminal) and triple negative (St. Gallen International Breast Cancer Conference 2011). These breast cancer subtypes show differences in response to therapies and prognosis. Amongst others prognosis is depended on hormone receptor positivity, extent and localization of metastases. Routine screening for metastatic disease is not part of the guidelines for breast cancer aftercare although in oligometastatic disease surgery or local ablative therapies can be used to improve outcome. We evaluated if tumor aftercare should be individualized due to different patterns of metastases of the breast cancer subtypes.

Methods: Four hospitals incorporated into the Regional Breast Center Dresden as a certified center of excellence for treating breast cancer. We retrospectively evaluated sites and characteristics of metastases and survival data according to the intrinsic breast cancer subtypes from patients treated between 2006 and 2011. Immunohistochemical detection of estrogen and progesterone receptor, grading and overexpression of HER2 oncogene was used for identifying tumor subtypes. All data were collected at the Clinical Cancer Registry Dresden.

Results: In 2006 routinely identification of overexpression of HER2 started. Since that time 2334 patients had therapy for breast cancer- 12,4% (290/2334) with metastatic disease (7.2%; 168/2334 primary and 5.2%; 122/2334 relapse). Mean duration of follow up was 38 months. Metastatic disease was more frequently found in HER2 enriched, 27.2%; 30/110, and triple negative, 19.7%; 44/223, than in the luminal subtypes: luminal A 8.3%; 107/1284, luminal B HER2 negative 12.2%; 23/188, luminal B HER2 positive 16%; 36/225. Luminal A and B HER2 negative subtypes showed a preference for solely bone metastases (43%; 56/130) which was rare in triple negative breast cancer (6.8% 3/44). If bone metastases occurred in triple negative breast cancer they mostly appeared together with visceral and/or brain metastatic disease (27%; 12/44). Solely visceral metastases were found in the HER2 enriched subtype (46.7%; 14/30), luminal B HER2 positive (38.9%; 14/36), and triple negative breast cancer (20.2%; 19/44). Brain metastases were more frequently observed in triple negative breast cancer (22.7%; 10/44). Overall survival rate at 5 years for metastatic disease was 38.5% (95%CI 28.2-52.5) for luminal A, 23.1% (95%CI 12.0-44.5) for luminal B (HER2 negative), 11.9% (95%CI 5.5-25.7) for luminal B (HER2 positive), 27.6% (95%CI 14.4-52.8) for HER2 enriched and 6.5% (95%CI 2.4-17.1) for triple negative subtype.

Conclusion: Different patterns of metastatic disease were seen according to the subtypes of breast cancer. An individualized tumor aftercare that includes screening for visceral metastasis might improve prognosis of patients with luminal B HER positive, HER enriched and triple negative subtype. Further investigation on patients eligible for metastatic surgery should be performed with longer follow up and evaluated with respect to post-interventional survival.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-06-48.