Search

Little is known about the factors that regulate the asymmetric division of cancer stem–like cells (CSC). Here, we demonstrate that EGFL6, a stem cell regulatory factor expressed in ovarian tumor cells and vasculature, regulates ALDH+ ovarian CSC. EGFL6 signaled at least in part via the oncoprotein SHP2 with concomitant activation of ERK. EGFL6 signaling promoted the migration and asymmetric division of ALDH+ ovarian CSC. As such, EGFL6 increased not only tumor growth but also metastasis. Silencing of EGFL6 or SHP2 limited numbers of ALDH+ cells and reduced tumor growth, supporting a critical role for EGFL6/SHP2 in ALDH+ cell maintenance. Notably, systemic administration of an EGFL6-neutralizing antibody we generated restricted tumor growth and metastasis, specifically blocking ovarian cancer cell recruitment to the ovary. Together, our results offer a preclinical proof of concept for EGFL6 as a novel therapeutic target for the treatment of ovarian cancer. Cancer Res; 76(21); 6396–409. ©2016 AACR.

Supplementary Methods

Supplementary Figures 1-8

Background: In women with HER2-positive breast cancer progressing during trastuzumab treatment, continuation of trastuzumab plus capecitabine (XH) showed a significantly improved overall response rate and time to progression compared with capecitabine (X) alone (von Minckwitz et al, J Clin Oncol 27:1999-2006, 2009). Here we report the final analysis of overall survival (OS). Methods: Patients (pts) with HER2-positive, locally advanced or metastatic breast cancer who progressed during treatment with trastuzumab with or without adjuvant and/or 1st-line metastatic chemotherapy were prospectively randomized to X (2500 mg/m2 on days 1-14, q3w) or XH (6 mg/kg, q3w). OS was a pre-specified secondary endpoint of the study. Results: Median follow up at June 2010 was 20.7 months. 59 of 74 and 60 of 77 pts died in the X alone and XH arm, respectively. Median OS was 20.6 and 24.9 months with X alone and XH, respectively. This difference was not statistically significant (HR=0.94 [0.65-1.35]; p=0.73). Cox proportional hazard model showed performance status, hormone receptor status and metastatic site as independent prognosticators for survival. No difference between treatment arms was observed for pts with a clinical response or clinical benefit, respectively. Pts who continued/restarted anti-HER2 treatment (trastuzumab or lapatinib) after 2nd progression (N=88) had an OS of 18.8 compared with 13.3 months for those who did not receive 3rd line treatment with anti-HER2 agents (N=52) (HR 0.63; p=0.02). Pts who continued treatment after progression as initially randomized (anti-HER2 treatment after XH (N=31) or no anti-HER2 treatment after X alone (N=53)) had an OS of 26.7 months and 20.4 months (HR 0.71; p=0.2). Conclusions: Final OS analysis of the GBG-26 study could not demonstrate a survival benefit for treatment beyond progression with trastuzumab. However in a post-hoc analysis, pts receiving anti-HER2 treatment as 3rd line therapy showed a better OS than those not receiving this targeted treatment. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P6-14-05.

Angiogenesis, the formation of new blood vessels from preexisting ones, is an indispensible process under normal physiological conditions such as embryonic development, certain stages of the female reproductive cycle and placenta formation during pregnancy as well as under pathological conditions such as wound healing, diabetic retinopathy, and cancer initiation, progression and metastasis. We have previously identified the molecular mechanism by which a zinc finger transcription factor, ZNF24, functions as a new inhibitor of tumor angiogenesis. ZNF24 represses the transcription of vascular endothelial growth factor (VEGF) in breast cancer cells via direct binding to an 11-bp fragment within the VEGF proximal promoter. In the current study, we have focused on the role of ZNF24 in modulating the angiogenic potential of the endothelial compartment of the tumor microenvironment. Utilizing primary human microvascular endothelial cells, we have found that silencing ZNF24 in these cells leads to significantly decreased endothelial cell proliferation. Quantitative real-time PCR array analyses have identified multiple cell cycle regulators as potential downstream targets of ZNF24, which may be responsible for the decreased proliferation in these cells. Moreover, knockdown of ZNF24 in microvascular endothelial cells leads to significantly decreased cell migration and invasion. Consistently, we found that VEGFR2 signaling and the proteolytic activity of matrix metalloproteinase-2 (MMP2) were significantly downregulated in these cells. We also determined the effect of ZNF24 silencing on the levels of major regulators of MMP2 proteolytic activity such as the tissue inhibitors of metalloproteinases (TIMPs) and other MMPs. Knockdown of ZNF24 does not induce significant changes in levels of these TIMPs and MMPs, suggesting that ZNF24 regulates MMP2 at the transcriptional level. Indeed, the mRNA level of MMP2 is significantly decreased in cells transfected with ZNF24 siRNA, indicating that ZNF24 may be potentiating endothelial cell invasion by positively regulating MMP2 transcription. In a pilot in vivo angiogenesis assay, knockdown of ZNF24 in microvascular endothelial cells leads to the significantly decreased formation of vascular networks when co-implanted with bone marrow-derived mesenchymal progenitor cells in immunodeficient mice. Taken together, these results demonstrate that ZNF24 may be playing an essential role in modulating the angiogenic potential of microvascular endothelial cells by regulating the proliferation and motility of these cells. (Supported by NIH P01 CA045548 and the Breast Cancer Research Foundation) Citation Format: Di Jia, Lan Huang, Joyce Bischoff, Marsha Moses. Modulating the angiogenic potential of human microvascular endothelial cells by an endogenous zinc finger transcription factor, ZNF24. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 30. doi:10.1158/1538-7445.AM2014-30

Background: The tyrosine-kinase inhibitor lapatinib (L) has shown to improve efficacy of cytotoxic and endocrine treatment in HER2-positive metastatic breast cancer (BC). Improved pathological complete response (pCR) rates were demonstrated by adding trastuzumab (T) to neoadjuvant chemotherapy. However, so far no head-to-head comparison of the two anti-HER2-agents is available. One primary aim of the GeparQuinto study was to improve the pCR rate by adding L instead of T to anthracycline-taxane-based neoadjuvant chemotherapy. We previously reported interim safety data of this study showing more diarrhea, skin changes, and hot flushes, but no cardiac events with L compared to T (von Minckwitz G et al, Ann Oncol 2010 in press). Patients and Methods: Patients (P) with untreated HER2-positive BC were eligible if they had cT3/4a-d; or estrogen (ER) and progesterone (PgR) receptor-negative; or ER/PgR-positive tumors with clinically N+ (for cT2) or pNSLN+ (for cT1) disease, and no increased cardiac risks. P were randomized to receive 4 cycles epirubicin/cyclophosphamide (EC) (90/600 mg/m2) q3w followed by 4 cycles docetaxel (D) (100mg/m2) given in combination with either T 6 (loading dose 8) mg/kg every 3 weeks or L 1000-1250 mg/d throughout all cycles. pCR was defined as no invasive or non-invasive tumor residuals in breast and nodes. We assumed a pCR rate of 26% with ECT-DT (based on GeparQuattro) and expected a pCR of 37% for ECL-DL (odds ratio 1.67). A two-sided Pearson's Chi2 with α=0.05 and β=0.20 calculated a sample size of 613 P. Results: Between May ‘07 and June ‘10 597 P were randomized to ECT-DT (N=299) and ECL-DL (N=298). Median tumor size was 40/40 [T/L] mm (clinically) and 28/29 mm (sonographically); 4.7%/4.3% had T4a-c, 14.8%/14.2% T4d, 2.9%/1.8% bilateral, 17.0%/17.7% multifocal, and 9.0%/12.1% multicentric disease, 96.7%/97.9% had non-lobular, 45.6%/48.9% grade 3, 70.0%/67.7% node-positive, and 56.5%/56.0% ER and PgR-negative disease. Baseline characteristics were well balanced between the treatment arms. The last randomized P will have surgery early Dec'10. Final results on histological response and surgical outcome will be reported. Conclusion: The GeparQuinto trial will provide for the first time randomized phase III efficacy data on the comparison of L and H in combination to chemotherapy for patients with early breast cancer. As pCR has been confirmed as being a surrogate marker for long-term outcome after T treatment, this result will give insight on the overall efficacy of L in patients with early breast cancer. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr S3-1.

Abstract #3115 Introduction: The number of scientific meetings with breast cancer-related topics increases constantly and therefore so does the number of presented abstracts. Many of these abstracts are not reported in peer-reviewed journals post-conference. This lack of final publication constitutes a loophole in scientific reporting. Furthermore, it retrospectively assesses the quality of the review process the abstracts undergo prior to the meetings. We critically reviewed the publication rates of breast cancer-related abstracts submitted to the four major oncology meetings for breast cancer in Europe and North America in 2002. Material and methods: The authors identified all breast cancer-related abstracts presented or published at the annual meetings of the ASCO, SABCS, EBCC and ESMO in 2002. First, a MEDLINE search identified the abstracts written by the first, second and last authors that matched a journal article by these authors. Second, the match between the study described in the abstract and full publication was determined. Results: A total number of 1620 abstracts were analyzed. Mean rate of full publication: 44,5%; publication rate of EUR meetings: 33,3%; publication rate of NA meetings: 52,7% (p Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3115.