A 16 Yin Yang gene expression ratio signature for ER+/node- breast cancer.

Breast cancer is one of the leading causes of cancer death in women. It is a complex and heterogeneous disease with different clinical outcomes. Stratifying patients into subgroups with different outcomes could help guide clinical decision making. In this study, we used two opposing groups of genes, Yin and Yang, to develop a prognostic expression ratio signature. Using the METABRIC cohort we identified a16-gene signature capable of stratifying breast cancer patients into four risk levels with intention that low-risk patients would not undergo adjuvant systemic therapy, intermediate-low-risk patients will be treated with hormonal therapy only, and intermediate-high- and high-risk groups will be treated by chemotherapy in addition to the hormonal therapy. The 16-gene signature for four risk level stratifications of breast cancer patients has been validated using 14 independent datasets. Notably, the low-risk group (n = 51) of 205 estrogen receptor-positive and node negative (ER+/node-) patients from three different datasets who had not had any systemic adjuvant therapy had 100% 15-year disease-specific survival rate. The Concordance Index of YMR for ER+/node negative patients is close to the commercially available signatures. However, YMR showed more significance (HR = 3.7, p = 8.7e-12) in stratifying ER+/node- subgroup than OncotypeDx (HR = 2.7, p = 1.3e-7), MammaPrint (HR = 2.5, p = 5.8e-7), rorS (HR = 2.4, p = 1.4e-6), and NPI (HR = 2.6, p = 1.2e-6). YMR signature may be developed as a clinical tool to select a subgroup of low-risk ER+/node- patients who do not require any adjuvant hormonal therapy (AHT).

Statin Use at the Time of Initiation of Androgen Deprivation Therapy and Time to Progression in Patients With Hormone-Sensitive Prostate Cancer.

IMPORTANCE: Statin use has been associated with improved prostate cancer outcomes. Dehydroepiandrosterone sulfate (DHEAS) is a precursor of testosterone and a substrate for SLCO2B1, an organic anionic transporter. We previously demonstrated that genetic variants of SLCO2B1 correlated with time to progression (TTP) during receipt of androgen deprivation therapy (ADT). Statins also use SLCO2B1 to enter cells, and thus we hypothesized that they may compete with DHEAS uptake by the tumor cells. OBJECTIVE: To evaluate whether statin use prolongs TTP during ADT for hormone-sensitive prostate cancer. DESIGN, SETTING, AND PARTICIPANTS: In vitro studies were performed using prostate cancer cell lines at an academic, comprehensive cancer center. Statin use was retrospectively analyzed in 926 patients who had received ADT for biochemical or metastatic recurrence or de novo metastatic prostate cancer between January 1996 and November 2013. MAIN OUTCOMES AND MEASURES: To determine whether statins interfere with DHEAS uptake, we performed in vitro studies using prostate cancer cell lines. Next, we queried our institutional clinical database to assess for an association between statin use and TTP during ADT using multivariable Cox regression analysis and adjusted for known prognostic factors. RESULTS: In vitro, we demonstrated that statins block DHEAS uptake by competitively binding to SLCO2B1. In our ADT cohort of 926 patients, 283 (31%) were taking a statin at ADT initiation. After a median follow-up of 5.8 years, 644 patients (70%) had experienced disease progression while receiving ADT. Median TTP during ADT was 20.3 months (95% CI, 18-24 months). Men taking statins had a longer median TTP during ADT compared with nonusers (27.5 [95% CI, 21.1-37.7] vs 17.4 [95% CI, 14.9-21.1] months; P < .001). The association remained statistically significant after adjusting for predefined prognostic factors (adjusted hazard ratio, 0.83 [95% CI, 0.69-0.99]; P = .04). The positive statin effect was observed for both patients with and without metastases (adjusted hazard ratio, 0.79 [95% CI, 0.58-1.07] for M0 disease and 0.84 [95% CI, 0.67-1.06] for M1 disease; P for interaction = .72). CONCLUSIONS AND RELEVANCE: Statin use at the time of ADT initiation was associated with a significantly longer TTP during ADT even after adjustment for known prognostic factors. Our in vitro finding that statins competitively reduce DHEAS uptake, thus effectively decreasing the available intratumoral androgen pool, affords a plausible mechanism to support the clinical observation of prolonged TTP in statin users.

CYP19 genetic polymorphism haplotype AASA is associated with a poor prognosis in premenopausal women with lymph node-negative, hormone receptor-positive breast cancer.

Given the critical role of CYP19 in estrogen synthesis, we investigated the influence of CYP19 gene polymorphisms on the clinical outcome of lymph node- (LN-) negative, hormone receptor- (HR-) positive early breast cancers. Genotyping for the CYP19 polymorphisms rs4646 (A/C), rs1065779 (A/C), CYP19 (TTTA)n (short allele/long (S/L) allele using the 7 TTTA repeat polymorphism as the cut-off), and rs1870050 (A/C) was performed on 296 patients with LN-negative, HR-positive breast cancers. All patients received adjuvant hormonal therapy. Associations were examined between these 4 genotypes and 6 common haplotypes of CYP19 and distant disease-free survival (DDFS), disease-free survival (DFS), and overall survival (OS). Patients were divided into the 6 subhaplotypes of CCLA (41.1%), AASA (17.1%), CASA (11.9%), CCLC (8.9%), CCSA (7.5%), AASC (8.9%), and others (4.6%). In premenopausal patients, haplotype AASA was significantly associated with a poor DDFS (adjusted hazard ratio (aHR), 3.3; P = 0.001), DFS (aHR, 2.5; P = 0.0008), and OS (aHR, 2.9; P = 0.0004) after adjusting for age, tumor size, tumor grade, estrogen receptor status, progesterone receptor status, chemotherapy, pathology, adjuvant hormone therapy, menopausal status, and radiotherapy. Furthermore, haplotype AASA remained a negative prognostic factor for premenopausal patients receiving adjuvant chemotherapy in terms of DDFS (aHR, 4.5; P = 0.0005), DFS (HR, 3.2; P = 0.003), and OS (HR, 6.4; P = 0.0009). However, in postmenopausal patients, haplotype AASA was not associated with a poor prognosis, whereas the AASC haplotype was significantly associated with a poor DFS (aHR, 3.1; P = 0.03) and OS (aHR, 4.4; P = 0.01). Our results indicate that, in patients with LN-negative, HR-positive breast cancers, genetic polymorphism haplotype AASA is associated with poor survival of premenopausal women but does not affect survival of postmenopausal women.

Prevalence of BRCA mutations in an unselected population of triple-negative breast cancer.

BACKGROUND: This study assessed BRCA1 and BRCA2 mutation prevalence in an unselected cohort of patients with triple-negative breast cancer (BC). METHODS: One hundred ninety-nine patients were enrolled. Triple negativity was defined as <1% estrogen and progesterone staining by immunohistochemistry and HER-2/neu not overexpressed by fluorescence in situ hybridization. Having given consent, patients had BRCA1 and BRCA2 full sequencing and large rearrangement analysis. Mutation prevalence was assessed among the triple-negative BC patients and the subset of patients without a family history of breast/ovarian cancer. Independent pathological review was completed on 50 patients. RESULTS: Twenty-one deleterious BRCA mutations were identified--13 in BRCA1 and 8 in BRCA2 (prevalence, 10.6%). In 153 patients (76.9%) without significant family history (first-degree or second-degree relatives with BC aged <50 years or ovarian cancer at any age), 8 (5.2%) mutations were found. By using prior National Comprehensive Cancer Network (NCCN) guidelines recommending testing for triple-negative BC patients aged <45 years, 4 of 21 mutations (19%) would have been missed. Two of 21 mutations (10%) would have been missed using updated NCCN guidelines recommending testing for triple-negative BC patients aged <60 years. CONCLUSIONS: The observed mutation rate was significantly higher (P = .0005) than expected based on previously established prevalence tables among patients unselected for pathology. BRCA1 mutation prevalence was lower, and BRCA2 mutation prevalence was higher, than previously described. Additional mutation carriers would have met new NCCN testing guidelines, underscoring the value of the updated criteria. Study data suggest that by increasing the age limit to 65 years, all carriers would have been identified.

Cribriform-morular variant of papillary thyroid carcinoma: characteristic histologic feature of adenomatous polyposis. A case report.

We report the case of a 24-year-old woman with familial adenomatous polyposis and diagnosed with cribriform-morular variant of papillary thyroid carcinoma. Neck ultrasound and computed tomography identified multiple nodules in the thyroid gland and neck lymph nodes. The cytological analysis was compatible with the diagnosis of papillary cancer of the thyroid. Total thyroidectomy with lymph node dissection was performed. The histological analysis established the diagnosis of cribriform-morular variant of papillary thyroid carcinoma. Despite preoperative findings suggesting an aggressive form of thyroid cancer with lymph node involvement, the final diagnosis was a variant of papillary thyroid carcinoma often associated with familial adenomatous polyposis and known to have a good prognosis.

An iron regulatory gene signature predicts outcome in breast cancer.

Changes in iron regulation characterize the malignant state. However, the pathways that effect these changes and their specific impact on prognosis remain poorly understood. We capitalized on publicly available microarray datasets comprising 674 breast cancer cases to systematically investigate how expression of genes related to iron metabolism is linked to breast cancer prognosis. Of 61 genes involved in iron regulation, 49% were statistically significantly associated with distant metastasis-free survival. Cases were divided into test and training cohorts, and the supervised principal component method was used to stratify cases into risk groups. Optimal risk stratification was achieved with a model comprising 16 genes, which we term the iron regulatory gene signature (IRGS). Multivariable analysis revealed that the IRGS contributes information not captured by conventional prognostic indicators (HR = 1.61; 95% confidence interval: 1.16-2.24; P = 0.004). The IRGS successfully stratified homogeneously treated patients, including ER+ patients treated with tamoxifen monotherapy, both with (P = 0.006) and without (P = 0.03) lymph node metastases. To test whether multiple pathways were embedded within the IRGS, we evaluated the performance of two gene dyads with known roles in iron biology in ER+ patients treated with tamoxifen monotherapy (n = 371). For both dyads, gene combinations that minimized intracellular iron content [anti-import: TFRC(Low)/HFE(High); or pro-export: SLC40A1 (ferroportin)(High)/HAMP(Low)] were associated with favorable prognosis (P < 0.005). Although the clinical utility of the IRGS will require further evaluation, its ability to both identify high-risk patients within traditionally low-risk groups and low-risk patients within high-risk groups has the potential to affect therapeutic decision making.

Hydroxyflutamide enhances cellular sensitivity to 5-fluorouracil by suppressing thymidylate synthase expression in bicalutamide-resistant human prostate cancer cells.

We investigated the antitumor effects of combination therapy with anti-androgens and 5-fluorouracil (5-FU), and examined the underlying mechanism of the treatment. Initially, we established the bicalutamide-resistant subline CDX25R from the androgen receptor (AR)-positive human prostate cancer cell line LNCaP through continuous exposure to bicalutamide. CDX25R cells lost the ability to respond to androgens, but still expressed AR. They showed significant resistance to bicalutamide, but had high sensitivity to hydroxyflutamide (OH-flutamide) compared with LNCaP cells. The CDX25R subline was thus considered to be a suitable model for prostate cancer that has developed resistance to first-line hormonal therapy but shows sensitivity to an alternative approach. Combined treatment with 5-FU and OH-flutamide had a synergistic effect on CDX25R cells. OH-flutamide decreased expression of the transcription factor E2F1, and subsequently of thymidylate synthase (TS), in CDX25R cells but not in AR-negative DU145 cells. This suggested that OH-flutamide enhanced the growth-inhibitory activity of 5-FU in CDX25R cells by reducing TS expression through the AR pathway. Combined therapy with 5-FU and OH-flutamide may, therefore, be appropriate for patients with prostate cancer that has acquired resistance to initial hormone therapy including bicalutamide.

[CYP2D6 polymorphisms and tamoxifen: therapeutic perspectives in the management of hormonodependent breast cancer patients]. / Polymorphismes du CYP2D6 et tamoxifène : perspectives thérapeutiques dans la prise en charge des cancers du sein hormonodépendants.

Tamoxifen is a prodrug mainly metabolized by the CY2D6 cytochrome. More than 80 variants of the CYP2D6 gene have been identified. They predict four different enzymatic phenotypes: ultra-rapid metabolizers (UM), extensive metabolizers (EM), intermediate metabolizers (IM) and poor metabolizers (PM). Six retrospectives studies suggest a link between some polymorphisms of the CYP2D6 and tamoxifen efficacy and two studies have found no statistically significant data. Today, level of proof remains insufficient to recommend the testing of a patient's genotype before tamoxifen prescription. Designing prospective studies is necessary before considering therapy strategies based on pharmacogenetics data. In pre-menopausal breast cancer PM or IM patients, an increase in dosage of tamoxifen or a treatment with LH-RH analogues with aromatase inhibitors (AI) may be beneficial instead of the actual recommendations of a 5-year tamoxifen therapy. In postmenopausal EM patients, tamoxifen may be as efficient as AI. In post-menopausal PM patients, a switch strategy may be inferior to a 5-year IA strategy, which would therefore be the standard of care.

Tumor aromatase expression as a prognostic factor for local control in young breast cancer patients after breast-conserving treatment.

INTRODUCTION: We sought to determine whether the levels of expression of 17 candidate genes were associated with locoregional control after breast-conserving treatments of early-stage breast cancers in young, premenopausal women. METHODS: Gene expression was measured by using RT-PCR in the breast tumors of a series of 53 young (younger than 40 years), premenopausal patients. All treatments consisted of primary breast-conserving surgery followed by whole-breast radiotherapy (+/- regional lymph nodes) with or without systemic treatments (chemotherapy +/- hormone therapy). The median follow-up was 10 years. RESULTS: The 10-year locoregional control rate was 70% (95% CI, 57% to 87%). In univariate analysis, no clinical/pathologic prognostic factors were found to be significantly associated with decreased locoregional control. Expression of three genes was found to be significantly associated with an increased locoregional recurrence rate: low estrogen-receptor beta, low aromatase, and high GATA3. Two others were associated with only a trend (P < 0.10): low HER1 and SKP2. In multivariate analysis, only the absence of aromatase was significantly associated with an increased locoregional recurrence rate (P = 0.003; relative risk = 0.49; 95% CI 0.29 to 0.82). CONCLUSIONS: Recent data give credit to the fact that breast cancer in young women is a distinct biologic entity driven by special oncogenic pathways. Our results highlight the role of estrogen-signaling pathways (mainly CYP19/aromatase, GATA3, and ER-beta) in the risk of locoregional recurrence of breast cancer in young women. Confirmation in larger prospective studies is needed.

Clinical roundtable monograph: a multidisciplinary approach to the use of oncotype DX in clinical practice.

Recently, recommendations for the use of the Oncotype DX assay in estrogen receptor-positive node-negative breast cancer patients were incorporated into guidelines from both the American Society of Clinical Oncology and the National Comprehensive Cancer Network. The Oncotype DX assay is a diagnostic test which measures changes in a set of 21 genes in order to predict the likelihood of disease recurrence and also to predict which patients are most likely to respond to chemotherapy. Oncotype DX has been available commercially since January 2004 and has been used for more than 85,000 patients. Drs. William J. Gradishar, Nora M. Hansen, and Barbara Susnik answered questions regarding the incorporation of the Oncotype DX breast cancer assay into routine clinical practice. This expert dialog offers an update and clinical insights into when, how, and why clinicians might incorporate the Oncotype DX assay into the management of their breast cancer patients. Also, the latest research into the benefit of the Oncotype DX assay in node-positive patients is discussed. Finally, sample case studies offer clinically relevant examples of the practical application of the Oncotype DX assay.

Hormone receptor status and pathologic response of HER2-positive breast cancer treated with neoadjuvant chemotherapy and trastuzumab.

BACKGROUND: The aim of this study was to compare the extent of pathologic response in patients with HER2-positive (HER2+) breast cancer treated with standard neoadjuvant chemotherapy, with or without trastuzumab (H), according to hormone receptor (HR) status. PATIENTS AND METHODS: We included 199 patients with HER2+ breast cancer from three successive cohorts of neo-adjuvant chemotherapy on the basis of paclitaxel (Taxol) (P) administered weekly (w) or three weekly (3-w), followed by 5-fluorouracil (F), doxorubicin (A) or epirubicin (E), and cyclophosphamide (C). Residual cancer burden (RCB) was determined from pathologic review of the primary tumor and lymph nodes and was classified as pathologic complete response (pCR) or minimal (RCB-I), moderate (RCB-II), or extensive (RCB-III) residual disease. RESULTS: In HR-positive (HR+) cancers, a higher rate of pathologic response (pCR/RCB-I) was observed with concurrent H + 3-wP/FEC (73%) than with 3-wP/FEC (34%, P = 0.002) or wP/FAC (47%; P = 0.02) chemotherapy alone. In HR-negative (HR-) cancers, there were no significant differences in the rate of pathologic response (pCR/RCB-I) from 3-wP/FAC (50%), wP/FAC (68%), or concurrent H + 3-wP/FEC (72%). CONCLUSIONS: Patients with HR+/HER2+ breast cancer obtained significant benefit from addition of trastuzumab to P/FEC chemotherapy; pathologic response rate was similar to that seen in HR-/HER2+ breast cancers.

Efficacy of sulforaphane is mediated by p38 MAP kinase and caspase-7 activations in ER-positive and COX-2-expressed human breast cancer cells.

Sulforaphane is an antioxidant and a potent stimulator of natural detoxifying enzyme and associated with lowered risk of cancer that is associated with the consumption of cruciferous vegetables. The chemopreventive effects of SFN was investigated using the MCF-7 human breast cancer cells and the M13SV1-immortalized human breast luminal epithelial cells. Sulforaphane reduced proliferation in MCF-7 cells and inhibited cyclooxygenase-2 expression in M13SV1 cells treated with 12-O-tetradecanoylphorbol-13-acetate (TPA). The chemopreventive effects of sulforaphane were associated with p38 mitogen-activated protein kinase suggest its important role in cell survival/apoptosis regulation and stabilization of cyclooxygenase-2. Sulforaphane upregulates p38 in MCF-7 cells and prevented TPA-reduced phosphorylation of p38 in M13SV1 cells, but activated caspase-7 associated with apoptosis in MCF-7 cells. These results suggest that sulforaphane may be an alternative candidate for targeted prevention of ER-positive and cyclooxygenase-2-induced phenotypes and breast cancer.

Comparative effects of DHEA and DHT on gene expression in human LNCaP prostate cancer cells.

BACKGROUND: DHEA is widely used as a dietary supplement in older men. Because DHEA can be converted to androgens or estrogens, such use may promote prostate cancer. In this study, the effects of DHEA were compared with those of DHT using gene expression array profiles in human LNCaP prostate cancer cells. MATERIALS AND METHODS: LNCaP cells were exposed to DHEA (300 nM), DHT (300 nM), or vehicle for 48 h, and mRNA expression was measured using Affymetrix HU-95 gene chips. Gene expression values were sorted in ascending order on the p-values corresponding to the extent of differential RNA expression between control and either hormone treatment. RESULTS: S100 calcium binding protein, neurotensin, 24-dehydrocholesterol reductase, and anterior-gradient 2 homologue were the four most differentially expressed genes (p-values all < 3 x 10(-5)). Nested tests of differential expression revealed lesser effects of DHEA versus DHT treatment (p < 0.01) for the S100 calcium binding protein and neurotensin genes. Microarray findings were confirmed by QRT-PCR. The top 83 genes exhibiting differential expression after DHEA or DHT were used for pathway analysis. DHT decreased expression of more genes involved in intercellular communication, signal transduction, nucleic acid binding and transport, and in structural components, such as myosin and golgin, than DHEA. CONCLUSION: These data revealed consistent, measurable changes in gene expression patterns following treatment of LNCaP prostate cancer cells with DHEA and DHT. Understanding the mechanisms of DHEA versus DHT actions in the prostate may help clarify the separate and interactive effects of androgenic and estrogenic actions in prostate cancer progression.

Molecular signatures of soy-derived phytochemicals in androgen-responsive prostate cancer cells: a comparison study using DNA microarray.

The present study utilized microarray technology as a tool to elucidate the molecular signatures of soy-derived phytochemicals in the human androgen-responsive prostate cancer cell line LNCaP. Global gene expression pattern analysis of LNCaP cells exposed to 0, 1, 5, or 25 microM of the soy-derived phytochemicals equol and daidzein were conducted and compared. The data were further compared with previously generated data from exposure of LNCaP cells to the same doses of genistein, a soy isoflavone. Multidimensional scaling (MDS) analyses of the expression patterns suggest that these compounds exerted differential effects on gene expression in LNCaP cells. Further examination of specific gene changes revealed that these compounds differentially modulated genes in multiple cellular pathways, including the cell-cycle pathway genes. However, the three compounds also exerted similar effect on genes belonging to several other important cellular pathways. A universal effect of the three compounds on androgen-responsive genes, IGF-1 pathway gene, and MAP kinase-related pathway gene was observed. These results provide the foundation for establishing molecular signatures for equol, daidzein, and genistein. Moreover, these results also allow for the identification of candidate mechanism(s) by which soy phytochemicals and soy may act in prostate cancer cells.

Genomic alterations identified by array comparative genomic hybridization as prognostic markers in tamoxifen-treated estrogen receptor-positive breast cancer.

BACKGROUND: A considerable proportion of estrogen receptor (ER)-positive breast cancer recurs despite tamoxifen treatment, which is a serious problem commonly encountered in clinical practice. We tried to find novel prognostic markers in this subtype of breast cancer. METHODS: We performed array comparative genomic hybridization (CGH) with 1,440 human bacterial artificial chromosome (BAC) clones to assess copy number changes in 28 fresh-frozen ER-positive breast cancer tissues. All of the patients included had received at least 1 year of tamoxifen treatment. Nine patients had distant recurrence within 5 years (Recurrence group) of diagnosis and 19 patients were alive without disease at least 5 years after diagnosis (Non-recurrence group). RESULTS: Potential prognostic variables were comparable between the two groups. In an unsupervised clustering analysis, samples from each group were well separated. The most common regions of gain in all samples were 1q32.1, 17q23.3, 8q24.11, 17q12-q21.1, and 8p11.21, and the most common regions of loss were 6q14.1-q16.3, 11q21-q24.3, and 13q13.2-q14.3, as called by CGH-Explorer software. The average frequency of copy number changes was similar between the two groups. The most significant chromosomal alterations found more often in the Recurrence group using two different statistical methods were loss of 11p15.5-p15.4, 1p36.33, 11q13.1, and 11p11.2 (adjusted p values < 0.001). In subgroup analysis according to lymph node status, loss of 11p15 and 1p36 were found more often in Recurrence group with borderline significance within the lymph node positive patients (adjusted p = 0.052). CONCLUSION: Our array CGH analysis with BAC clones could detect various genomic alterations in ER-positive breast cancers, and Recurrence group samples showed a significantly different pattern of DNA copy number changes than did Non-recurrence group samples.

Worse survival for TP53 (p53)-mutated breast cancer patients receiving adjuvant CMF.

BACKGROUND: TP53 has been described as a prognostic factor in many malignancies, including breast cancer. Whether it also might be a predictive factor with reference to chemo- and endocrine therapy is more controversial. PATIENTS AND METHODS: We investigated relapse-free (RFS), breast cancer-corrected (BCCS) and overall survival (OS) related to TP53 status in node-positive breast cancer patients that had received polychemotherapy [cyclophosphamide, methotrexate, 5-fluorouracil (CMF)] and/or endocrine therapy (tamoxifen). Sequence analyses of the whole TP53 coding region was performed in 376 patients operated on for primary breast cancer with axillary lymph node metastases between 1984 and 1989 (median follow-up time 84 months). RESULTS: TP53 mutations were found in 105 patients (28%). We found 90 (82%) of the 110 mutations in the more frequently analysed exons 5-8, while the other 20 (18%) were located in exons 3-4 and 9-10, respectively. Univariate analyses showed TP53 to be a significant prognostic factor with regard to RFS, BCCS and OS in patients who received adjuvant CMF. CONCLUSIONS: TP53 mutations might induce resistance to certain modalities of breast cancer therapy. Sequence-determined TP53 mutation was of negative prognostic value in the total patient population and in the CMF treated patients.

Inhibition of cyclooxygenase (COX)-2 expression by Tet-inducible COX-2 antisense cDNA in hormone-refractory prostate cancer significantly slows tumor growth and improves efficacy of chemotherapeutic drugs.

PURPOSE: Overexpression of the proinflammatory enzyme cyclooxygenase (COX)-2 is associated with the progression of various malignancies; the role of COX-2 in prostate cancer is less clear. The significance of COX-2 in prostate cancer growth and response to chemotherapy was investigated in an androgen-refractory prostate cancer cell line using a Tet-inducible antisense COX-2 expression system. EXPERIMENTAL DESIGN: An antisense COX-2 cDNA construct under the control of a doxycycline-inducible promoter was transfected into a prostate cancer cell line, PC-3ML. Modulations of cell growth, apoptosis, and chemosensitivity in the presence or absence of doxycycline were analyzed. Tumor incidence, growth rate, and response to two cytotoxic drugs, COL-3 [chemically modified tetracycline-3-(6-demethyl-6-deoxy-4-dedimethylamino-tetracycline)] and Taxotere (docetaxel), were investigated in tumor xenografts. Apoptotic incidences and tumor microvessel density in tumors were determined by immunohistochemistry. RESULTS: Conditional suppression of COX-2 in PC-3ML caused reduced cell proliferation, decreased levels of phosphorylated AKT, G(0)-G(1) arrest, and increased apoptosis and caspase-3 activity. Suppression of COX-2 increased Bax protein and decreased Bcl-x(L) protein in vitro. COX-2 antisense-expressing PC-3ML tumors showed a 57% growth delay compared with nontransfected or vector controls. Oral administration of COL-3 (40 mg/kg, oral gavage) or Taxotere (2.3 mg/kg, intraperitoneally; 3x per week) in tumor-bearing mice further slowed tumor growth (65% and approximately 94%, respectively). Compared with the control group, the occurrence of apoptosis in antisense COX-2 tumors was eight times higher, and the tumor microvessel density was three times lower. CONCLUSIONS: These results provide direct evidence that constitutive expression of COX-2 in prostate cancer has both angiogenic and cytoprotective functions. Suppression of tumor cell COX-2 is sufficient to enhance chemotherapy response in prostate cancer.

Identification of HRPAP20: a novel phosphoprotein that enhances growth and survival in hormone-responsive tumor cells.

The prolactin (PRL)-dependent rat Nb2 T lymphoma is a valuable model for investigation of molecular mechanisms that underlie tumor progression in hormone-dependent cancers. mRNA differential display was used to screen for novel gene products expressed in hormone-stimulated or differentiating agent-treated Nb2 sublines. From numerous transcripts identified, DNA sequencing and GenBank analysis revealed a novel 289-bp fragment. Using 5'-rapid amplification of complementary ends-PCR, this fragment was used to clone a unique 2117-bp cDNA, designated HRPAP20 (hormone-regulated proliferation-associated protein), in rat lymphoma cells. Computer-assisted sequence analysis revealed a single open reading frame that encoded a putative 20.2-kDa protein. The effect of hormone stimulation to alter expression of HRPAP20 was evaluated by Northern blot analysis of total RNA obtained from PRL-stimulated, lactogen-dependent Nb2-11 cells. Quiescent cells, synchronized in the G(0)-G(1) phase of cell cycle, exhibited reduced HRPAP20 expression compared with exponentially proliferating cultures. The addition of mitogenic concentrations of PRL to stationary cells increased HRPAP20 mRNA accumulation within 4-6 h, corresponding to G(1) cell cycle progression. Immunoblot analysis showed that PRL also increased HRPAP20 protein levels within 4 h. In addition, PRL stimulated serine phosphorylation of the HRPAP20 protein with a similar kinetic pattern. Stable transfection of the HRPAP20 cDNA into Nb2-11 cells significantly (P < 0.01) increased proliferation in the absence of hormonal stimulation and inhibited apoptosis induced by lactogen deprivation (P < 0.001). In the hormone-independent and highly malignant Nb2-SFJCD1 subline, the constitutive expression of HRPAP20 was markedly reduced by exposure of the cells to dietary differentiating agents (butyrate, retinoic acid, and vitamin D(3)). After removal of these substances, PRL stimulated its expression in a manner similar to that observed in PRL-dependent Nb2-11 cells. HRPAP20 expression was also evaluated in MCF-7 cells. Its expression was detectable in quiescent cultures; addition of PRL significantly (P < 0.05) increased HRPAP20 during G(1) cell cycle progression. Exposure of the cells to butyrate or retinoic acid reduced HRPAP20 expression, similar to the effects of these substances in the malignant rat lymphoma. Stable transfection of HRPAP20 into MCF-7 cells significantly (P < 0.006) increased proliferation in the absence of hormone stimulation and augmented survival in the absence of serum (P < 0.05). We conclude that HRPAP20 is a phosphoprotein that is required for proliferation and survival of hormone-dependent tumor cells.

Gene profiling and promoter reporter assays: novel tools for comparing the biological effects of botanical extracts on human prostate cancer cells and understanding their mechanisms of action.

The use of botanical mixtures is commonplace in patients with prostate cancer, yet the majority of these products have not been rigorously tested in clinical trials. Here we use PC-SPES, a combination of eight herbs that has been shown to be effective in clinical trials in patients with prostate cancer, as a model system to demonstrate 'proof of principle' as to how gene expression profiling coupled with promoter assays can evaluate the effect of herbal cocktails on human prostate cancer. In addition, we demonstrate how such approaches may be used for standardization of herbal extract activity by comparing the gene profile of PC-SPES with that of PC-CARE, a product with a similar herbal composition. Since prior studies have shown that PC-SPES contains estrogenic organic compounds, and such compounds are known to affect prostate cancer, an important issue is whether these are the primary drivers of the gene profile. Our data suggest that gene expression profiles of LNCaP human prostate cancer cells in response to PC-SPES are different from those found when diethylstilbestrol (DES), a synthetic estrogen, is used, suggesting that the estrogenic moieties within PC-SPES do not drive this expression signature. In contrast, the expression profile of PC-CARE was almost identical to that of DES, highlighting that mixtures containing similar herbal compositions do not necessarily result in similar biological activities. Interestingly, these three agents cause similar in vitro morphological changes and growth effects on LNCaP. To validate the expression profiling data, we evaluated the protein expression and promoter activity of prostate-specific antigen (PSA), a gene induced by PC-SPES but repressed by DES. In order to gain a mechanistic understanding of how PC-SPES and DES affect PSA expression differently, LNCaP cells were transiently transfected with wild-type and mutagenized PSA promoter, ARE concatemers and appropriate controls. We provide evidence that androgen response elements (ARE) II and III within the promoter region are responsible for the suppressive effects of DES and stimulatory effects of PC-SPES. In addition, we show that the effects on PSA transcription are ARE specific in the case of DES while PC-SPES affects this promoter nonspecifically. In conclusion, expression profiling coupled with mechanistic target validation yield valuable clues as to the mode of action of complex botanical mixtures and provides a new way to compare objectively mixtures with similar components either for effect or quality assurance prior to their use in clinical trials.

Selenium modulation of cell proliferation and cell cycle biomarkers in human prostate carcinoma cell lines.

Prostate cancer (PCA) is the most common histological malignancy and the second leading cause of cancer deaths among North American men. There has been considerable interest in the chemopreventative properties of selenium. In this study, we assessed whether selenium inhibits cell growth and associated cell cycle regulatory proteins. Human PCA cells (LNCaP, PC3, PC3-AR2, and PC3-M) were incubated with and without selenium (Seleno-DL-methionine, 150 microM) for 24, 48, and 72 h. Cells were fixed and stained with propidium iodide for flow cytometry analysis. In parallel experiments, total protein was extracted, immunoprecipitated with cyclin E antibody, and analyzed by Western blot for the expression of cell cycle markers. Treatment with selenium caused G1 arrest and an 80% reduction in the S phase of LNCaP with no effect on PC3. However, PC3 cells transfected with the androgen receptor (PC3-AR2) exhibited a G2/M arrest and a marked reduction (57%) in the S phase during cell cycle progression. In the analysis of cell cycle regulatory molecules, selenium-treated cells demonstrated a significant induction of cyclin-dependent kinase inhibitors Cip1/p21 and Kip1/p27. These data suggest that selenium possesses strong antiproliferative properties in regard to human PCA. This effect appears to be dependent on the presence of a functioning androgen receptor. This provides a theoretical basis for Phase III studies of selenium in PCA prevention.