Endocrine-related Cancer Research Articles

Bisphenol A induces cell cycle arrest in primary and prostate cancer cells through EGFR/ERK/p53 signaling pathway activation.

Bisphenol A (BPA) belongs to the class of chemicals known as endocrine disruptors and has been also involved in the pathogenesis and progression of endocrine related cancer such as breast and prostate cancers. Here, we have investigated the effect of BPA in human prostate cancer LNCaP cells and in human non-transformed epithelial prostate EPN cells. Our data showed that BPA induces the down regulation of cyclin D1 expression and the upregulation of the cell cycle inhibitors p21 and p27, leading to cell cycle arrest. Interestingly, we found that the BPA anti-proliferative response depends on a strong and rapid activation of epidermal growth factor receptor (EGFR), which stimulates ERK-dependent pathway. This, in turn, induces expression of p53 and its phosphorylation on residue Ser15, which is responsible for cell cycle arrest. EGFR activation occurs upon a cross talk with androgen (AR) and estradiol receptor-β (ERβ) which are known to bind BPA.Altogether, these findings show a novel signaling pathway in which EGFR activation plays a key role on BPA-induced cell cycle inhibition through a pathway involving AR and ERβ/EGFR complexes, ERK and p53. Our results provide new insights for understanding the molecular mechanisms in human prostate cancer. On the other, they could allow the development of new compounds that may be used to overcome human prostate cancer resistance to endocrine therapy in promising target therapeutic approaches.

Targeting mitotic pathways for endocrine-related cancer therapeutics.

A colossal amount of basic research over the past few decades has provided unprecedented insights into the highly complex process of cell division. There is an ever-expanding catalog of proteins that orchestrate, participate and coordinate in the exquisite processes of spindle formation, chromosome dynamics and the formation and regulation of kinetochore microtubule attachments. Use of classical microtubule poisons has still been widely and often successfully used to combat a variety of cancers, but their non-selective interference in other crucial physiologic processes necessitate the identification of novel druggable components specific to the cell cycle/division pathway. Considering cell cycle deregulation, unscheduled proliferation, genomic instability and chromosomal instability as a hallmark of tumor cells, there lies an enormous untapped terrain that needs to be unearthed before a drug can pave its way from bench to bedside. This review attempts to systematically summarize the advances made in this context so far with an emphasis on endocrine-related cancers and the avenues for future progress to target mitotic mechanisms in an effort to combat these dreadful cancers.

Peptides derived from the sst5TMD4 extracellular domain increase malignancy of endocrine-related cancer cells

Peptides derived from the sst5TMD4 extracellular domain increase malignancy of endocrine-related cancer cells

Transcription factor activity of estrogen receptor α activation upon nonylphenol or bisphenol A treatment enhances the in vitro proliferation, invasion, and migration of neuroblastoma cells.

Many kinds of endocrine-disrupting chemicals (EDCs), for example, the environmental estrogens bisphenol A and nonylphenol, may regulate the activity of estrogen receptor α (ERα) and therefore induce potential disruption of normal endocrine function. However, the involvement of EDCs in human cancers, especially in endocrine-related cancer neuroblastoma regulation, is not very clear. In this work, results showed that upon bisphenol A or nonylphenol treatment, the transcription factor activity of ERα was significantly increased in neuroblastoma cell line SH-SY5Y. Bisphenol A and nonylphenol could enhance ERα activity via recruiting it to the target gene promoter. Furthermore, treatment of bisphenol A and nonylphenol enhanced the in vitro proliferation, invasion, and migration ability of neuroblastoma cells. By investigating the role of EDC-induced ERα upregulation, our data extend the understanding of the function of EDCs and further suggest that ERα might be a potential therapeutic target in human neuroblastoma treatment.

Risk factors for subsequent endocrine-related cancer in childhood cancer survivors

Long-term adverse health conditions, including secondary malignant neoplasms, are common in childhood cancer survivors. Although mortality attributable to secondary malignancies declined over the past decades, the risk for developing a solid secondary malignant neoplasm did not. Endocrine-related malignancies are among the most common secondary malignant neoplasms observed in childhood cancer survivors. In this systematic review, we describe risk factors for secondary malignant neoplasms of the breast and thyroid, since these are the most common secondary endocrine-related malignancies in childhood cancer survivors. Radiotherapy is the most important risk factor for secondary breast and thyroid cancer in childhood cancer survivors. Breast cancer risk is especially increased in survivors of Hodgkin lymphoma who received moderate- to high-dosed mantle field irradiation. Recent studies also demonstrated an increased risk after lower-dose irradiation in other radiation fields for other childhood cancer subtypes. Premature ovarian insufficiency may protect against radiation-induced breast cancer. Although evidence is weak, estrogen-progestin replacement therapy does not seem to be associated with an increased breast cancer risk in premature ovarian-insufficient childhood cancer survivors. Radiotherapy involving the thyroid gland increases the risk for secondary differentiated thyroid carcinoma, as well as benign thyroid nodules. Currently available studies on secondary malignant neoplasms in childhood cancer survivors are limited by short follow-up durations and assessed before treatment regimens. In addition, studies on risk-modifying effects of environmental and lifestyle factors are lacking. Risk-modifying effects of premature ovarian insufficiency and estrogen-progestin replacement therapy on radiation-induced breast cancer require further study.

Expression of Estrogen Receptor Beta Predicts Oncologic Outcome of pT3 Upper Urinary Tract Urothelial Carcinoma Better Than Aggressive Pathological Features.

Upper urinary tract urothelial carcinoma (UT-UC) is rare and treatment options or prognostic markers are limited. There is increasing evidence indicating that urothelial carcinoma may be an endocrine-related cancer. The aim of this study was to analyze the prognostic effect of estrogen receptor beta (ERβ) on the outcome of UT-UC. From 2005 to 2012, this study included 105 patients with pT3 UT-UC. Perioperative factors, pathological features, and ERβ immunostaining were reviewed and prognostic effects were examined by multivariate analysis. This study divided patients into either the ERβ-high (n = 52) or ERβ-low (n = 53) group and analyzed their oncologic outcomes. All pathological features except infiltrating tumor architecture (significantly higher incidence in ERβ-low group, p = 0.004) are symmetric in both groups. Low ERβ expression was significantly correlated with local recurrence and distant metastasis in univariate analysis (p = 0.035 and 0.004, respectively) and multivariate analysis (p = 0.05 and 0.008, respectively). Cell line study also proved that knock down of ERβ cause less UTUC proliferation and migration. In addition, ERβ agonist also enhanced the cytotoxic and migration inhibition effect of cisplatin and ERβ antagonist cause the UTUC cell more resistant to cisplatin. This result may help identify patients in need of adjuvant therapy or develop potential targeted therapy.

Abstract B04: The long noncoding RNA - PRINS as a novel recurrence biomarker and tumor suppressor for adrenocortical carcinoma

Abstract Background & Aims: Adrenocortical carcinoma (ACC) has recurrence rates of ~50% and new methods of predicting recurrence are required to complement existing biomarkers (Ki-67 staining) to tailor adjuvant therapy. We have shown expression of PRINS, a long noncoding RNA (lncRNA) can predict ACC recurrence, which is the first clinical association of this lncRNA with outcome in cancer.(1) In keratinocytes where PRINS was discovered, PRINS interacts with the protein nucleophosphmin (NPM) allowing its translocation from the cytoplasm to the nucleus.(2) In the nucleus NPM binds to TP53 to increase its transcriptional activity.(3) TP53 mutations are a key driver of ACC. The aim of this study was to establish a biological basis for PRINS as a biomarker by investigating a tumour suppressor RNA action in ACC. Method: PRINS expression was quantified in clinical samples using RT-qPCR and Ki-67 staining using immunohistochemistry (IHC). PRINS expression in ACC cells (NCI-H295R) was restored using the mammalian expression vector containing full length of PRINS cDNA transcript (pcDNA3.1[PRINS]). Cell phenotypes were compared to cells transfected with an empty vector (pcDNA3.1[Blank]). Transcriptome analysis was performed on clinical samples of ACC (n=10) and normal adrenal cortex (n=6) using the ArrayStar Human LncRNA V3.0 microarray. Results: Using RT-PCR NCI-H295R cells were found to have low expression of PRINS compared to clinical samples of normal adrenal cortex (Fold change 0.37, P<0.05) and ACC (Fold change 0.51, P<0.05). Transfection with pcDNA3.1[PRINS] lead to restoration of PRINS expression above that of normal adrenal cortex (P<0.05). In the pcDNA3.1[PRINS] NCI-H295R cells, rates of apoptosis were increased by 49.8% as assessed by Annexin V assays (P<0.05) and cPARP protein expression compared to pcDNA3.1[Blank] transfected cells. Reduced cell proliferation of 30-40% was also found using MTS assays (P<0.05) in PRINS transfected cells. Using RNA FISH, PRINS was localised to the cell cytoplasm. Correlation of ~26,000 mRNA transcripts found PRINS expression to be correlated with 48 mRNAs (Pearson Correlation Coefficients > 80%, corrected P<0.05), including p53 related genes – TNFRSF11B, MKI-67 and TTK. MKI67 codes for the protein Ki-67 and in clinical samples, PRINS relative expression had a moderate negative linear relationship to Ki-67 IHC scoring (n=14, R2=0.38, P=0.02). Following PRINS restoration in NCI-H295R cells, MKI-67 was unchanged, however TP53 was increased (Fold change 1.5, P<0.001) and TNFRSF11B reduced (Fold change 0.56, P<0.05) supporting a mechanism of increased apoptosis. Conclusions: This first report of PRINS acting as a tumour suppressor in cancer supports the association with ACC outcomes. As PRINS is also under-expressed in breast and prostate cancer it offers potential as a biomarker in other cancers to improve quality of life and further opportunities for research into a novel mechanism of TP53 action in cancer. This project was supported by a Sydney Vital Research Scholarship Grant. 1. Glover, A. R. et al. Long noncoding RNA profiles of adrenocortical cancer can be used to predict recurrence. Endocrine-Related Cancer 22, 99–109 (2014). 2. Szegedi, K. et al. Expression and Functional Studies on the Noncoding RNA, PRINS. Int J Mol Sci 14, 205–225 (2011). 3. Colombo, E., Marine, J.-C., Danovi, D., Falini, B. & Pelicci, P. G. Nucleophosmin regulates the stability and transcriptional activity of p53. Nature Cell Biology 4, 529–533 (2002). Citation Format: Anthony R. Glover, Jing T. Zhao, Lauren J S Joo, Anthony J. Gill, Bruce G. Robinson, Stan B. Sidhu. The long noncoding RNA - PRINS as a novel recurrence biomarker and tumor suppressor for adrenocortical carcinoma. [abstract]. In: Proceedings of the AACR Special Conference on Noncoding RNAs and Cancer: Mechanisms to Medicines ; 2015 Dec 4-7; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2016;76(6 Suppl):Abstract nr B04.

WAP four-disulfide core domain protein 2 gene(WFDC2) is a target of estrogen in ovarian cancer cells.

BackgroundWAP four-disulfide core domain protein 2 (WFDC2) shows a tumor-restricted upregulated pattern of expression in ovarian cancer.MethodsWe investigated the role of estradiol (E2) on cell growth in estrogen-sensitive or estrogen-insensitive ovarian cancer cell lines. Real-time (RT)-PCR and western blotting were used to examine the expression of WFDC2 at RNA and protein levels. Growth traits of cells transfected with WFDC2-shRNA or blank control were assessed using MMT arrays. Cell apoptosis was analyzed using annexin V-FITC/PI and flow cytometry. Estrogen receptor expression was evaluated using RT-PCR and flow cytometry. Apoptosis-related proteins induced by E2 directly and indirectly were determined using an antibody array comparing cells transfected with WFDC2- shRNA or a blank control.ResultsHigh-dose (625 ng/ml) E2 increased the expression of WFDC2 in HO8910 cells at both the mRNA and protein levels. However, E2 had no effect on WFDC2 expression in estrogen-insensitive SKOV3 cells. Of interest, knockdown of WFDC2 enabled a considerable estrogen response in SKOV3 cells in terms of proliferation, similar to estrogen-responsive HO8910 cells. This transformation of SKOV3 cells into an estrogen-responsive phenotype was accompanied by upregulation of estrogen receptor beta (ERß) and an effect on cell apoptosis under E2 treatment by regulating genes related to cell proliferation and apoptosis.ConclusionsWe postulate that increased WFDC2 expression plays an important role in altering the estrogen pathway in ovarian cancer, and the identification of WFDC2 as a new player in endocrine-related cancer encourages further studies on the significance of this gene in cancer development and therapy.Electronic supplementary materialThe online version of this article (doi:10.1186/s13048-015-0210-y) contains supplementary material, which is available to authorized users.

Modulatory role of 17β-estradiol in the tumor microenvironment of thyroid cancer.

Thyroid cancer (TC) is an endocrine related cancer and is well coupled with the female reproductive hormone, 17β-estradiol (estrogen). Plenty of articles have discussed the role of tumor microenvironment (TME) with different types of tumors in a broad-spectrum but the role of female reproductive hormone, that is, involvement of estrogen in TME of TC have not been reviewed elsewhere. The aim of this review is to analyze how 17β-estradiol affects the TME of TC and also that subsequently leads to progression of cancer. This review is given a new insight on: 1) the estrogen's involvement in TME of TC; 2) how it interferes with the complex cross talk of signaling pathways established between cancer cells, host cells, and their surrounding extracellular matrix; and 3) the important factors of microenvironment comprising inflammation, hypoxia, angiogenesis, metastasis, various growth factors and fibroblasts in stromal cells.

Would the combination of everolimus with endocrine-therapy help in FGFR2 positive serous endometrial cancer?

Chemotherapy is a critical approach in the treatment of advanced or recurrent endometrial cancer. The use of chemotherapy is now the standard treatment for women with early-stage disease. However, there are no agents approved by the US Food and Drug Administration for the metastatic setting of endometrial cancer, which has a very low chance to be treated with success. Due to the great expectation on novel targeting agents in advanced endometrial cancer, new drugs against specific molecular pathways with particular focus on PI3KCA/AKT/mTOR axis are emerging as promising treatments for endometrial cancer with aggressive phenotype [1]. The very issue is the lack of progress in cancer treatment due to the heterogeneity and the genetic complexity of many tumours leading to an urgent knowledge of the molecular profile of an individual's tumour to guide appropriate treatment selection. We have read with enthusiasm the article by Slomovitz et al published in Journal of Clinical Oncology on January 26, 2015 where it was reported the increased clinical benefit rate with the combination of letrozole and everolimus in women with recurrent endometrial cancer along with a manageable toxicity [2]. Moreover, patients with endometriod histotype carrying the CTNNB1 mutations underwent to a good response to treatment. On the counterpart the serous histology did not respond with the same rate to mTOR inhibition; moreover they have not identified based on the molecular analysis they performed a possible responsive-subtype of the serous cancer. The Cancer Genome Atlas has led to the molecular reclassification of endometrial cancer. These genomic advances are determinant for the proper selection of the adequate therapy in the future of the patient care. In the genomic era, clinicians and molecular oncologists should invest their efforts in finding “druggable” targets for the available drugs on the market. In our clinical experience, letrozole alone is already able to modulate the mTOR axis in breast cancer [3] suggesting its use also in other endocrine-related cancer such as estrogen receptors positive endometrial cancer. In our experience, the molecular analysis of the primary tumor or of the metastasis from endometrial cancer showed low percentage rate of mutations of PIK3CA and KRAS according on what reported by Slomovitz et al [2]. As previously reported that from the minimal genetic variations in the PI3K or FGFR pathways or CCND1, derives the most benefit from EVE based-therapy (HR = 0.27 vs 0.40 for the full NGS population) [4], in three serous endometrial cancers not responsive to conventional therapies, we applied for further molecular analysis, a part KRAS, PIK3CA and proliferation related genes, with particular regards to the staining of the estrogen receptor and FGFR2 FISH-based evaluation (Figure 1 A e B). The combination of 1gr medroxyprogesterone acetate daily and 10 mg everolimus daily induced stable radiological response of the liver metastases and partial radiological response in lung metastases during the time course of treatment in 2 patients with FGFR2 amplification (Figure 1 C and D). No response was detected in 1 patient without amplification of FGFR signal. Amplification or mutation of fibroblast growth factor receptor (FGFR) has been reported in endometrial cancers with a frequency of 10% and FGFR2 may represent a novel molecular target for the treatment of endometrial cancer [5]. Activation of FGFR induces PI3K and AKT activities through recruitment and tyrosine phosphorylation of the docking protein Gab1 that results in the activation of PI3K [6]. In our FGFR2+ve patients, we obtained, accordingly to the mRECIST Criteria, stable disease longer than 12 months in line with the positive data from the recent progression free survival analysis from the BOLERO-2 trial [7]. These results suggest that longer stable disease maybe achieved in the absence of a direct alteration in the PI3K/AKT/mTOR pathway, even when multiple molecular aberrations are present. However, FGFR2 may modulate the PIK3CA/AKT/mTOR axis perhaps explaining in part the response. Slomovitz et reported that only few patients with serous endometrial cancer responded to the combination of letrozole/everolimus and maybe they were FGFR 1 or 2 amplified. Figure 1 Biological and radiological features: A) Estrogen Receptor, B) FGFR2 Amplification; C) Target lesion at basal CT scan, D) Target lesion after 12 months of treatment Thus, the combination of everolimus and aromatase inhibitors has the change to show some activity in the particular subtype of EC as the FGFR2+ve serous carcinoma. Tumors with ER expression are dependent upon downstream growth factor signaling and may respond better with the addition of molecular inhibitors based on the proper target selection. Indeed, our reports encourage the perspective investigation of combination of everolimus along with hormone-therapy in pre-treated FGFR2+ recurrent endometrial cancer patients. Specific molecular analysis with focus on FGFR signalling in serous endometrial cancer is mandatory.

The activation of type 1 corticotropin releasing factor receptor (CRF-R1) inhibits proliferation and promotes differentiation of neuroblastoma cells in vitro via p27Kip1 protein up-regulation and c-Myc mRNA down-regulation

Our group has previously shown that corticotropin releasing factor (CRF) inhibits proliferation of human endocrine-related cancer cell lines via the activation of CRF type-1 receptors (CRF-R1). Tumors originating from the nervous system also express CRF receptors but their role on neoplastic cell proliferation was poorly investigated. Here we investigated the effect of CRF receptor stimulation on nervous system-derived cancer cells, using the SK-N-SH (N) human neuroblastoma cell line as an experimental model. We found that SK-N-SH (N) cells express functionally active CRF-R1, whose activation by CRF and the cognate peptide urocortin (UCN) is associated to reduced cell proliferation and motility, as well as neuronal-like differentiation. UCN did not interfere with cell viability and cell-cycle arrest. Those effects seem to be mediated by a mechanism involving the activation of cAMP/PKA/CREB pathway and the subsequent downstream increase in p27Kip1 and underphosphorylated retinoblastoma protein levels, as well as reduced c-Myc mRNA accumulation.

Targeting unfolded protein response in cancer and diabetes.

The maturation of secretory and membrane proteins in the endoplasmic reticulum (ER) is tightly regulated by the unfolded protein response (UPR), a signal transduction pathway maintaining ER protein folding homeostasis. However, certain ER states are incompatible with cell survival and therefore the UPR may choose to eliminate severely disrupted cells by apoptosis. This is accomplished primarily through the activation of the transcription factor CCAAT-enhancer-binding protein homologous protein (CHOP). In the April 2015 issue of Endocrine-Related Cancer, researchers from the universities of South Carolina and Athens (Greece) suggested a novel mechanism of CHOP-mediated apoptosis connected with the suppression of a prominent cell cycle regulator with anti-apoptotic activity, p21. These findings and suggested clinical applications, such as potentiation of cancer chemotherapy and a novel therapeutic approach for type 2 diabetes, are discussed in the context of UPR.

Radionuclide therapy of endocrine-related cancer

This article gives an overview of the established radionuclide therapies for endocrine-related cancer that already have market authorization or are currently under evaluation in clinical trials. Radioiodine therapy is still the gold standard for differentiated iodine-avid thyroid cancer. In patients with bone and lung metastases (near) total remission is seen in approximately 50% and the 15-year survival rate for these patients is approximately 90%. In contrast to the USA, meta-iodobenzylguanidine (MIBG) therapy has market approval in Europe. According to the current literature, in the setting of advanced stage neuroblastoma and malignant pheochromocytoma or paraganglioma, radiological remission can be achieved in >30% and symptom control in almost 80% of the treated patients. Somatostatin receptor targeted radionuclide therapies (e.g. with DOTATATE or DOTATOC) demonstrated promising results in phase 2 trials, reporting progression-free survival in the range of 24-36 months. A first phase 3 pivotal trial for intestinal carcinoids is currently recruiting and another trial for pancreatic neuroendocrine tumors is planned. Radiopharmaceuticals based on glucagon-like peptide 1 (GLP1) or minigastrins are in the early evaluation stage for application in the treatment of insulinomas and medullary thyroid cancer. In general, radiopharmaceutical therapy belongs to the group of so-called theranostics which means that therapy is tailored for individual patients based on molecular imaging diagnostics to stratify target positive or target negative tumor phenotypes.

Zoledronic acid at the time of castration prevented castration-induced bone metastasis in mice.

Androgen deprivation therapy (ADT) is known to cause bone loss in a majority of patients with castration-resistant prostate cancer (CRPC). A study published in this issue of Endocrine-Related Cancer by Ottewell and colleagues shows that ADT increased bone resorption and triggered growth of disseminated prostate cancer (CaP) cells to form bone metastasis using an in vivo model. However, prevention of bone decay by weekly administration of zoledronic acid (ZOL) at the time of castration prevented ADT-induced tumor growth in bone. Recently, two publications from Japan have demonstrated that ZOL combined with ADT improved outcomes for patients with treatment-naïve CaP with bone metastasis. The mechanistic cause for these patients having an improved overall survival compared with those who were treated with ZOL after ADT initiation or before metastasis development was never explained. Ottewell and colleague's study now suggests that it is the bone loss caused by ADT that promoted bone metastasis, and if ZOL is administered at the time of ADT initiation, it would prevent this bone loss and prolong skeletal-related event-free survival.

Epigenetic alterations in endocrine-related cancer.

Aberrant epigenetics is a hallmark of cancer, and endocrine-related tumors are no exception. Recent research has been identifying an ever-growing number of epigenetic alterations in both genomic DNA methylation and histone post-translational modification in tumors of the endocrine system. Novel microarray and ultra-deep sequencing technologies have allowed the identification of genome-wide epigenetic patterns in some tumor types such as adrenocortical, parathyroid, and breast carcinomas. However, in other cancer types, such as the multiple endocrine neoplasia syndromes and thyroid cancer, tumor information is limited to candidate genes alone. Future research should fill this gap and deepen our understanding of the functional role of these alterations in cancer, as well as defining their possible clinical uses.

Lymphocytes and thyroid cancer: more to it than meets the eye?

Immune responses by innate and adaptive immune cells are crucial for the suppression of carcinogenesis and tumor spread. Effector T cells such as, cytotoxic CD8(+) T (CTL), natural killer (NK), and NK T cells (NKT cells) prevent tumor growth by their ability to induce apoptosis in cancer cells. To circumvent anti-tumor immunity, tumors commonly attract regulatory T cells (Treg), which suppress the function of CTL and NKT cells in a contact- and cytokine-dependent manner. Recent findings in patients with thyroid cancer have suggested that an imbalance between immune suppressive and anti-tumor cells occurs during thyroid carcinogenesis. However, the composition and regulation of immune responses in thyroid cancer are still elusive and a comprehensive immune profile of thyroid cancer is missing. In this issue of Endocrine-Related Cancer, Imam et al. compare immune profiles between patients with papillary thyroid carcinoma and autoimmune thyroiditis. Their data suggest that an imbalance between immunosuppressive Treg cells and effector T cells occurs during papillary thyroid carcinogenesis. Their study identified double-negative T cells as a novel key factor involved in this process. Future research is required to recapitulate these findings, to elucidate the mechanisms by which the immune response is regulated and to evaluate if this process might be used for the therapeutical management of thyroid cancer.

Disruption of mutated BRAF signaling modulates thyroid cancer phenotype

BackgroundThyroid cancer is the most common endocrine-related cancer in the United States and its incidence is rising rapidly. Since among various genetic lesions identified in thyroid cancer, the BRAFV600E mutation is found in 50% of papillary thyroid cancers and 25% of anaplastic thyroid cancers, this mutation provides an opportunity for targeted drug therapy. Our laboratory evaluated cellular phenotypic effects in response to treatment with PLX4032, a BRAFV600E-specific inhibitor, in normal BRAF-wild-type thyroid cells and in BRAFV600E-positive papillary thyroid cancer cells.MethodsNormal BRAF-wild-type thyroid cells and BRAFV600E-mutated papillary thyroid cancer cells were subjected to proliferation assays and analyzed for cell death by immunofluorescence. Cell cycle status was determined using an EdU uptake assay followed by laser scanning cytometry. In addition, expression of proteins within the MAPK signal transduction pathway was analyzed by Western blot.ResultsPLX4032 has potent anti-proliferative effects selectively in BRAF-mutated thyroid cancer cells. These effects appear to be mediated by the drug’s activity of inhibiting phosphorylation of signaling molecules downstream of BRAF within the pro-survival MAPK pathway. Interestingly, PLX4032 promotes the phosphorylation of these signaling molecules in BRAF-wild-type thyroid cells.ConclusionsThese findings support further evaluation of combinational therapy that includes BRAFV600E inhibitors in thyroid cancer patients harboring the BRAFV600E mutation.

Abstract P1-03-01: Circulating CAIX as a biomarker in breast cancer

Abstract Introduction: Carbonic anhydrase-IX (CAIX) facilitates the reversible hydration of carbon dioxide to bicarbonate and protons, a process integral to maintaining pH differences across the cancer cell plasma membrane. CAIX is regulated by hypoxia inducible factor-1 alpha (HIF-1 alpha) and is essential for the elimination of acid loads generated by glycolysis. High CAIX expression is associated with poor prognosis and chemoresistance in breast cancer patients (pts) (1-3). To explore the role of CAIX as a possible biomarker for predicting breast cancer therapies, we measured plasma CAIX levels in response to various chemotherapy regimens, including anti-angiogenics, in several breast cancer clinical trials. Methods: Circulating plasma CAIX was quantified using a commercially available enzyme-linked immunosorbent assay (ELISA) kit (R & D Systems). We evaluated the plasma stability of CAIX by quantifying levels within 1 hour as well as at 24 and 48 hours post phlebotomy in healthy controls (n = 10). We also evaluated the ideal anticoagulant for sample collection and stability of CAIX levels over time in healthy controls. For our analysis in breast cancer pts, we quantified plasma CAIX levels in two populations treated on chemotherapeutic clinical trials: 1) locally advanced breast cancer (LABC) pts treated in the neoadjuvant setting with paclitaxel in combination with sunitinib followed by anthracycline (AC) based chemotherapy (n = 63); 2) metastatic breast cancer (MBC) pts treated with systemic chemotherapy with either irinotecan + etoposide; or paclitaxel + a novel immunomodulatory agent (n = 22). Results: In healthy control subjects, plasma levels of CAIX were stable at all time points tested (within1 hour, 24 hrs, 48 hours post phlebotomy) with no significant change on repeat testing at 6 months. Average baseline plasma CAIX levels were lowest in normal controls (20.5 pg/ml) compared to pts with LABC (34.1 pg/ml) or MBC (90.7 pg/ml) (p = <0.001). In pts with LABC, CAIX rose significantly in response to paclitaxel/sunitinib (TS) therapy (p = 0.01) but not further with anthracycline based therapy (p = 0.37). The rise in response to TS was primarily in pts with baseline levels below the median. In pts with MBC treated with cytotoxic chemotherapies (without an anti-angiogenic) CAIX levels did not change in response to therapy. Discussion: Plasma CAIX is a robust biomarker that is stable at room temperature in plasma for at least 48hrs and over time in healthy controls. Plasma CAIX levels are elevated in pts with MBC when compared to those with LABC or normal controls. CAIX levels rise in response to anti-angiogenic therapy but not in response to cytotoxic chemotherapy. Our results suggest CAIX may be a robust and easily measured pharmacodynamic biomarker of anti-angiogenic induced hypoxia and HIF-1 alpha upregulation. 1. Potter CP and Harris AL. Br J Cancer. 89:2-7, 2003. 2. Betof AS, Rabbani ZN, Hardee ME, et al. BJ Cancer. 106:916-922, 2012. 3. Generali D, Fox Berruti A, et al. Endocrine-Related Cancer. 13:921-30, 2006. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-03-01.

IGF2 revs the steroidogenesis engine

Molecular understanding of how prostate cancers evade hormone therapy greatly increased over the last several years, and the realization that de novo steroidogenesis plays a significant role in tumor progression and therapeutic bypass has led to development of promising new therapeutics. In the April 2013 issue of Endocrine-Related Cancer, Lubik et al. revealed a new molecular pathway by which the IGF2 can ignite the de novo steroidogenesis engine and promote molecular events associated with tumor progression.

The changing roles of steroid nuclear receptors with prostate cancer progression

Estrogens were once used for the treatment of prostate cancer (PC). They may still be used in various parts of the world to that effect. Recent developments in the understanding of a role for estrogen receptor β (ERβ) in the development and progression of this disease resurrect the discussion on the intertwined roles of ERβ and the androgen receptor (AR) in promoting PC. A new article by Zellweger et al. in Endocrine-Related Cancer investigates the expression and assesses the activity of ERα and ERβ as well as the AR, in addition to a phosphorylated form of AR in hormone-naïve and castration-resistant PC.