Randomised phase II trial of weekly ixabepilone ± biweekly bevacizumab for platinum-resistant or refractory ovarian/fallopian tube/primary peritoneal cancer

BACKGROUND

This multi-center RP2 study assessed activity/safety of ixabepilone + bevacizumab compared to ixabepilone in platinum-resistant/refractory ovarian/fallopian tube/primary peritoneal cancer. Additional objectives were to examine the role of prior bevacizumab and taxanes, and explore class III-ß-tubulin (TUBB3) as a predictive biomarker.

METHODS

Participants were randomised to receive ixabepilone 20 mg/m2 days 1, 8, 15 with (IXA + BEV) or without (IXA) bevacizumab 10 mg/kg days 1, 15 every 28 days. Patients were stratified by prior BEV. The primary endpoint was PFS. OS, safety, and ORR served as secondary endpoints.

RESULTS

Among 76 evaluable patients who received IXA + BEV (n = 39) compared to IXA (n = 37), the ORR was 33% (n = 13) versus 8% (n = 3)(P = 0.004), durable at 6 months in 37% (n = 14) and 3% (n = 1) (P < 0.001). BEV significantly improved PFS (median:5.5 vs 2.2 months, HR = 0.33, 95%CI 0.19-0.55, P < 0.001) and OS (median:10.0 vs 6.0 months, HR = 0.52, 95%CI 0.31-0.87, P = 0.006). Both regimens were well-tolerated. TUBB3 expression did not predict response. Subgroup analyses revealed minimal effect of prior BEV or taxane resistant/refractory status on response to IXA + BEV.

CONCLUSIONS

IXA + BEV is a well-tolerated, effective combination for platinum/taxane-resistant ovarian cancer that extends PFS and likely OS relative to IXA monotherapy. Prior receipt of BEV should not preclude the use of IXA + BEV. TUBB3 is not a predictive biomarker.

CLINICAL TRIAL REGISTRATION

NCT3093155.

Microtentacle Formation in Ovarian Carcinoma

BACKGROUND

The development of chemoresistance to paclitaxel and carboplatin represents a major therapeutic challenge in ovarian cancer, a disease frequently characterized by malignant ascites and extrapelvic metastasis. Microtentacles (McTNs) are tubulin-based projections observed in detached breast cancer cells. In this study, we investigated whether ovarian cancers exhibit McTNs and characterized McTN biology.

METHODS

We used an established lipid-tethering mechanism to suspend and image individual cancer cells. We queried a panel of immortalized serous (OSC) and clear cell (OCCC) cell lines as well as freshly procured ascites and human ovarian surface epithelium (HOSE). We assessed by Western blot β-tubulin isotype, α-tubulin post-translational modifications and actin regulatory proteins in attached/detached states. We studied clustering in suspended conditions. Effects of treatment with microtubule depolymerizing and stabilizing drugs were described.

RESULTS

Among cell lines, up to 30% of cells expressed McTNs. Four McTN morphologies (absent, symmetric-short, symmetric-long, tufted) were observed in immortalized cultures as well as ascites. McTN number/length varied with histology according to metastatic potential. Most OCCC overexpressed class III ß-tubulin. OCCC/OSC cell lines exhibited a trend towards more microtubule-stabilizing post-translational modifications of α-tubulin relative to HOSE. Microtubule depolymerizing drugs decreased the number/length of McTNs, confirming that McTNs are composed of tubulin. Cells that failed to form McTNs demonstrated differential expression of α-tubulin- and actin-regulating proteins relative to cells that form McTNs. Cluster formation is more susceptible to microtubule targeting agents in cells that form McTNs, suggesting a role for McTNs in aggregation.

CONCLUSIONS

McTNs likely participate in key aspects of ovarian cancer metastasis. McTNs represent a new therapeutic target for this disease that could refine therapies, including intraperitoneal drug delivery.

Malignant Ascites in Ovarian Cancer: Cellular, Acellular, and Biophysical Determinants of Molecular Characteristics and Therapy Response

Ascites refers to the abnormal accumulation of fluid in the peritoneum resulting from an underlying pathology, such as metastatic cancer. Among all cancers, advanced-stage epithelial ovarian cancer is most frequently associated with the production of malignant ascites and is the leading cause of death from gynecologic malignancies. Despite decades of evidence showing that the accumulation of peritoneal fluid portends the poorest outcomes for cancer patients, the role of malignant ascites in promoting metastasis and therapy resistance remains poorly understood. This review summarizes the current understanding of malignant ascites, with a focus on ovarian cancer. The first section provides an overview of heterogeneity in ovarian cancer and the pathophysiology of malignant ascites. Next, analytical methods used to characterize the cellular and acellular components of malignant ascites, as well the role of these components in modulating cell biology, are discussed. The review then provides a perspective on the pressures and forces that tumors are subjected to in the presence of malignant ascites and the impact of physical stress on therapy resistance. Treatment options for malignant ascites, including surgical, pharmacological and photochemical interventions are then discussed to highlight challenges and opportunities at the interface of drug discovery, device development and physical sciences in oncology.

The Role of Eicosanoids in Gynecological Malignancies

Eicosanoids, bio-active lipid molecules, evoke a multitude of biological effects that directly affect cancer cells and indirectly affect tumor microenvironment. An emerging role has been shown for eicosanoids in the pathogenesis of gynecological malignancies which include cancers of the vulva, vagina, cervix, uterine, and ovary. Eicosanoid biosynthesis pathways start at the metabolism of phospholipids by phospholipase A2 then proceeding to one of three pathways: the cyclooxygenase (COX), lipoxygenase (LOX), or P450 epoxygenase pathways. The most studied eicosanoid pathways include COX and LOX; however, more evidence is appearing to support further study of the P450 epoxygenase pathway in gynecologic cancers. In this review, we present the current knowledge of the role of COX, LOX and P450 pathways in the pathogenesis of gynecologic malignancies. Vulvar and vaginal cancer, the rarest subtypes, there is association of COX-2 expression with poor disease specific survival in vulvar cancer and, in vaginal cancer, COX-2 expression has been found to play a role in mucosal inflammation leading to disease susceptibility and transmission. Cervical cancer is associated with COX-2 levels 7.4 times higher than in healthy tissues. Additionally, HPV elevates COX-2 levels through the EGFR pathway and HIV promotes elevated COX-2 levels in cervical tissue as well as increases PGE2 levels eliciting inflammation and progression of cancer. Evidence supports significant roles for both the LOX and COX pathways in uterine cancer. In endometrial cancer, there is increased expression of 5-LOX which is associated with adverse outcomes. Prostanoids in the COX pathway PGE2 and PGF2α have been shown to play a significant role in uterine cancer including alteration of proliferation, adhesion, migration, invasion, angiogenesis, and the inflammatory microenvironment. The most studied gynecological malignancy in regard to the potential role of eicosanoids in tumorigenesis is ovarian cancer in which all three pathways have shown to be associated or play a role in ovarian tumorigenesis directly on the tumor cell or through modulation of the tumor microenvironment. By identifying the gaps in knowledge, additional pathways and targets could be identified in order to obtain a better understanding of eicosanoid signaling in gynecological malignancies and identify potential new therapeutic approaches.

Multiple drug resistance-associated protein (MRP4) exports prostaglandin E2 (PGE2) and contributes to metastasis in basal/triple negative breast cancer

Cyclooxygenase-2 (COX-2) and its primary enzymatic product, prostaglandin E2 (PGE2), are associated with a poor prognosis in breast cancer. In order to elucidate the factors contributing to intratumoral PGE₂ levels, we evaluated the expression of COX-2/PGE₂ pathway members MRP4, the prostaglandin transporter PGT, 15-PGDH (PGE₂ metabolism), the prostaglandin E receptor EP4, COX-1, and COX-2 in normal, luminal, and basal breast cancer cell lines. The pattern of protein expression varied by cell line reflecting breast cancer heterogeneity. Overall, basal cell lines expressed higher COX-2, higher MRP4, lower PGT, and lower 15-PGDH than luminal cell lines resulting in higher PGE₂ in the extracellular environment. Genetic or pharmacologic suppression of MRP4 expression or activity in basal cell lines led to less extracellular PGE₂. The key finding is that xenografts derived from a basal breast cancer cell line with stably suppressed MRP4 expression showed a marked decrease in spontaneous metastasis compared to cells with unaltered MRP4 expression. Growth properties of primary tumors were not altered by MRP4 manipulation. In addition to the well-established role of high COX-2 in promoting metastasis, these data identify an additional mechanism to achieve high PGE₂ in the tumor microenvironment; high MRP4, low PGT, and low 15-PGDH. MRP4 should be examined further as a potential therapeutic target in basal breast cancer.

Abstract 1531: Distinct roles of CXCR3 isoforms in promoting breast cancer stem-like cell properties and metastasis

Growing evidence has demonstrated that the two major isoforms of chemokine receptor CXCR3 (CXCR3-A, CXCR3-B) both contribute to breast cancer pathogenesis and metastasis, however, in different ways. Understanding the relative contribution of each isoform is critical to optimize therapeutic strategies targeting CXCR3. Furthermore, the possible involvement of either CXCR3 isoform in cancer stem-like properties has not been reported. We examined the contribution of each isoform to metastasis using a panel of breast cell lines and a xenograft model of breast cancer; we also explored the role of major CXCR3 isoforms in the behavior of stem-like cells. CXCR3-A is more abundantly expressed than CXCR3-B in both primary human breast cancer tissue and in breast cancer cell lines. On the contrary, immortalized normal MCF-10A cells are CXCR3-B dominant. In basal-like MDA-MB-231 cells, CXCR3 ligand-stimulated proliferation is inhibited by CXCR3-B overexpression, with concurrent reduced activation of ERK1/2 and p38 kinases. Similarly, higher levels of CXCR3-B inhibit migration and invasion in vitro and metastasis in vivo. Accordingly, reduced CXCR3-B expression by gene-silencing enhances lung colonization in the xenograft model. Although exhibiting anti-proliferative and anti-metastatic roles in the non-stem cell population, CXCR3-B supports a cancer stem-like cell phenotype. In mammosphere-forming MDA-MB-231 cells, CXCR3-B is markedly up-regulated and mammosphere-forming capacity is further increased when overexpressing CXCR3-B. Likewise, soft agar growth is promoted by CXCR3-B overexpression. Accordingly, silencing CXCR3-B by shRNA inhibits stem-like properties. In conclusion, both isoforms need to be targeted to inhibit the pro-proliferative and pro-metastasis functions of CXCR3-A and the stem cell-promoting actions of CXCR3-B.

Citation Format: Yanchun Li, Jocelyn C. Reader, Xinrong Ma, Namita Kundu, Tyler Kochel, Amy M. Fulton. Distinct roles of CXCR3 isoforms in promoting breast cancer stem-like cell properties and metastasis. [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 1531. doi:10.1158/1538-7445.AM2015-1531

Abstract 3250: Prostaglandin E2 receptor EP1 suppresses breast cancer metastasis

Cyclooxygenases (COX-1 and COX-2) catalyze the formation of prostaglandins and play a role in the pathogenesis of breast cancer. Prostaglandin E2 (PGE2), the chief COX product in tumors, is the predominant protumorigenic prostanoid and mediates biological effects by binding to each of four EP receptors (EP1-4). Each receptor is coupled to different intracellular signaling pathways; and EP1 is coupled to calcium mobilization and PKC activation. Our published studies indicate that EP1 was detected in the cytoplasm and nucleus of benign ducts and malignant cells in invasive ductal carcinomas, and overall survival for women with tumors negative for nuclear EP1 was significantly worse than for women with any nuclear EP1 expression. Pharmacologic antagonism or reduction of EP1 expression increased metastatic capacity in a murine model of metastatic breast cancer. These data support our hypothesis that EP1 functions as a metastasis suppressor.

We now report that murine metastatic mammary tumor cell lines 410.4 and 66.1 have decreased EP1 mRNA expression compared to the non-metastatic cell line 410. Western blot analysis of total and subcellular fractions of EpH4 (normal, immortalized mammary epithelial) and malignant 410, 410.4 and 66.1 cell lines demonstrates that EP1 protein is present in the total and cytoplasmic fractions for all cell lines examined. Nuclear EP1 is detected in EpH4 and non-metastatic 410 cells; however, very little to no nuclear protein is detected in metastatic cell lines 410.4 and 66.1. The absence of nuclear EP1 in metastatic cell lines is consistent with the prognostic data that overall survival for women with tumors negative for nuclear EP1 was significantly worse.

Previously, we determined that reduction of EP1 expression leads to increased metastatic capacity; therefore, we investigated the effect of EP1 overexpression on lung colonization in 410.4 and 66.1 cells via tail vein injection in a syngeneic murine model of breast cancer. In 410.4 cells, EP1 overexpression leads to a 57%-97% decrease in metastasis, and in 66.1 cells EP1 overexpression resulted in a 10% - 38% decrease in lung tumor burden compared to vector control mice. The inverse correlation between EP1 expression and metastatic capacity supports our hypothesis that EP1 functions as a metastasis suppressor. We explored potential mechanisms leading to the alteration in the metastatic behavior in response to manipulation of the expression of EP1. We previously published that an EP1 antagonist altered adhesion to laminin in 410.4 cells. Overexpression of EP1 altered the expression of several integrin receptors in 410.4 and 66.1 cell lines including integrins alpha-V, alpha-6 and alpha-3. Also, overexpression of EP1 led to altered adhesion of these cells to several extracellular matrices including fibronectin, collagen, laminin and fibrinogen. Alteration of the adhesive properties of these cells by EP1 could contribute to the metastasis suppressor function of the EP1 receptor.

Citation Format: Jocelyn C. Reader, Xinrong Ma, Namita Kundu, Olga Goloubeva, Amy Fulton. Prostaglandin E2 receptor EP1 suppresses breast cancer metastasis. [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 3250. doi:10.1158/1538-7445.AM2015-3250

Divergent roles of CXCR3 isoforms in promoting cancer stem-like cell survival and metastasis

There is growing evidence that several chemokine receptors including CXCR3 contribute to metastasis of breast and other cancers, however, in order to target CXCR3 effectively, it is critical to understand the relative contribution of each CXCR3 isoform. Furthermore, the possible contribution of either major CXCR3 isoform (CXCR3-A, CXCR3-B) to cancer stem cell behavior has not been reported. We employed primary invasive ductal carcinomas, a panel of breast cell lines, and a xenograft model of metastatic breast cancer to examine the role of CXCR3 isoforms in the behavior of breast cancer stem-like cells and the contribution of each isoform to metastasis. In primary human breast cancer specimens as well as established breast cancer cell lines, CXCR3-A is more highly expressed than CXCR3-B. Conversely, immortalized normal MCF10A cells express more CXCR3-B relative to CXCR3-A. Overexpression of CXCR3-B in MDA-MB-231 basal-like cells inhibits CXCR3 ligand-stimulated proliferation, which is accompanied by reduced ligand-mediated activation of ERK1/2 and p38 kinases. Likewise, metastatic capacity is reduced in vivo by higher levels of CXCR3-B, and migratory and invasive properties are inhibited in vitro; conversely, silencing of CXCR3-B enhances lung colonization. In contrast to the anti-metastatic and anti-proliferative roles of CXCR3-B in the non-stem cell population, this isoform supports a cancer stem-like cell phenotype. CXCR3-B is markedly elevated in mammosphere-forming parental cells and overexpressing CXCR3-B further enhances mammosphere-forming potential as well as growth in soft agar; stem-like behavior is inhibited in MDA-MB-231shCXCR3-B cells. Targeting of both CXCR3 isoforms may be important to block the stem cell-promoting actions of CXCR3-B, while inhibiting the pro-proliferative and metastasis-promoting functions of CXCR3-A.

Abstract 3862: Mechanistic studies of the metastasis suppressor prostaglandin E2 receptor EP1 in breast cancer

Prostaglandin E2 (PGE2), the chief cyclooxygenase-2 enzyme (COX-2) product in tumors, is the predominant protumorigenic prostanoid and mediates biological effects by binding to each of four EP receptors (EP1-4). Each receptor is coupled to different intracellular signaling pathways with EP1 coupled to calcium mobilization and PKC. EP4, expressed on malignant breast cells, promotes metastasis, but a role for EP1 in metastasis has not been investigated. Our published studies indicate that EP1 was detected in the cytoplasm and nucleus of benign ducts and malignant cells in invasive ductal carcinomas, and overall survival for women with tumors negative for nuclear EP1 was significantly worse than for women with EP1 expression. Pharmacologic antagonism and reduction of EP1 expression increased metastatic capacity in our murine model of metastatic breast cancer. These data support our hypothesis that EP1 functions as a metastasis suppressor.

We now report that murine metastatic mammary tumor cell lines 410.4 and 66.1 have decreased EP1 mRNA expression compared to the non-metastatic cell line 410. We have also identified the presence of a variant EP1 (EP1v) transcript. EP1v has been identified previously in murine mast cell line MC/9 and rat uterus but not in malignant cells. EP1v has a pattern of mRNA expression different than full-length EP1. Compared to the cell line 410, EP1v expression is slightly increased in 410.4 and decreased in 66.1 cell lines.

In order to determine the underlying mechanism in which EP1 suppresses metastasis, a metastasis gene array was performed comparing gene expression in EP1-vector, and EP1-silenced 66.1 cell lines and several candidate genes were identified including Fn1, whose protein is altered during epithelial-to-mesenchymal transition. qPCR analysis of Fn1 expression in EP1-silenced and overexpression cell lines revealed an inverse relationship between EP1 and Fn1 expression. A decrease in EP1 expression led to a 4-5 fold increase in Fn1 expression; whereas, increased EP1 expression resulted in a 0.50 fold decrease in Fn1 expression. Like full length EP1, overexpression of EP1v also resulted in a decrease in Fn1 expression.

Bioinformatic analysis of the EP1 gene identified several CpG islands. DNA methylation analysis revealed hypermethylation of the CpG island nearest to the promoter in normal, non-metastatic and metastatic murine mammary tumor cell lines. In the quest to identify a clinically relevant strategy to increase expression of this protective receptor, we treated 410.4 and 66.1 cells with demethylating agent 5-azacytidine which resulted in an increase in EP1 expression. Our published studies show that EP1 acts to suppress metastasis and we are currently exploring the contribution of EP1v to this mechanism. These findings suggest that EP1 has the potential to be a new therapeutic target in reducing breast cancer metastasis and increasing overall cancer survival.

Citation Format: Jocelyn C. Reader, Xinrong Ma, Namita Kundu, Olga Goloubeva, Amy Fulton. Mechanistic studies of the metastasis suppressor prostaglandin E2 receptor EP1 in breast cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3862. doi:10.1158/1538-7445.AM2013-3862

Abstract 1456: Prostaglandin E2 receptor EP1 as a metastasis suppressor in breast cancer

The cyclooxygenase-2 enzyme (COX-2) is highly expressed in breast cancer and contributes to the metastatic process. Inhibition of COX-2 can decrease breast tumor growth and metastasis. Prostaglandin E2 (PGE2), the chief COX-2 product in tumors, has been identified as a predominant protumorigenic prostanoid. PGE2 mediates biological effects by binding to each of four EP receptors (EP1-4). EP1 is coupled to calcium mobilization and PKC; whereas, EP2 and EP4 activate PKA/cAMP, PI3K and ERK pathways. EP3 generally inhibits cAMP levels. EP4, expressed on malignant breast cells, promotes metastasis, but a role for EP1 in metastasis has not been investigated. Using a combination of immunohistochemistry, pharmacologic and genetic approaches, we studied EP1 expression in human breast tissue and function in a murine model of breast cancer metastasis. Our published studies indicate that EP1 was detected by immunohistochemistry in the cytoplasm and nucleus of benign ducts and malignant cells in invasive ductal carcinomas. Overall survival for women with tumors that were negative for nuclear EP1 was significantly worse than for women with EP1 expression. Additionally, pharmacologic antagonism and reduction of EP1 expression by shRNA increased metastatic capacity in our murine model of metastatic breast cancer. These data suggested that EP1 may function as a metastasis suppressor. We now report that murine mammary tumor cell lines 410, 410.4 and 66.1 have decreased mRNA levels of EP1 compared to normal murine mammary epithelial cell line EpH4. The EP1 receptor is normally coupled to calcium mobilization. Even though EP1 expression is decreased in mammary tumor cell lines, preliminary studies suggest the existence of functional EP1 receptor as PGE2 is capable of inducing calcium mobilization in 410.4 cells. In addition, treatment of 410 and 66.1 cells with 5-azacytidine is capable of increasing EP1 mRNA levels which may identify a clinically relevant strategy to increase expression of this protective receptor. We have also identified the presence of a variant EP1 (EP1v) transcript in this murine metastatic breast cancer model. EP1v has been identified previously in murine mast cell line MC/9 and in rat uterus; however, this is the first report that EP1v has been identified in malignant cells. Like EP1, mRNA expression of EP1v is also decreased in 410, 410.4 and 66.1 cell lines compared to EpH4 cells. Our published studies show that EP1 acts to suppress metastasis and we are currently exploring the contribution of EP1v to this mechanism. These findings suggest that EP1 has the potential to be a new therapeutic target in reducing breast cancer metastasis and increasing overall cancer survival.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1456. doi:10.1158/1538-7445.AM2011-1456

Regulation of differentiation by a PHD domain in the NUP98-PHF23 fusion protein

Acute myeloid leukemia (AML) is frequently associated with chromosomal translocations. These translocations produce specific fusion genes that play crucial roles in leukemogenesis. We recently identified a novel NUP98-PHF23 fusion in AML. In this study, we attempt to determine the role of NUP98-PHF23 protein and its plant homeodomain (PHD) and coiled-coil domain in regulation of cellular differentiation and protein distribution. We provide evidence that NUP98-PHF23, through its PHD domain, impairs TPA-induced differentiation of K562 cells. While the fusion protein localizes to the nucleus, its deletion mutant without the PHD domain resides exclusively in the nucleolus, suggesting a potential link between chromatin-binding PHD domain and nuclear architecture.

Analysis of 6q deletion in Waldenstrom macroglobulinemia

The frequency and prognostic significance of chromosome 6q deletion were investigated in a cohort of patients with Waldenstrom macroglobulinemia (WM). By interphase cytoplasmic fluorescence in situ hybridization with probes for 6q21 and 6q25, we detected hemizygous 6q deletions in the clonal lymphoplasmacytic cells in 13 (38%) out of 34 patients. Patients with 6q deletions had a lower IgM paraprotein levels than non-deleted patients (P = 0.04). There was no correlation between 6q deletion and other clinical features of WM. There was no significant difference in overall survival between 6q deleted and non-6q deleted groups (P = 0.92). Our study confirms that 6q deletion is a frequent event, but it does not appear to be a prognostic marker for patients with WM.

Sex differences in the chloride cotransporters, NKCC1 and KCC2, in the developing hypothalamus

In immature neurones, high basal [Cl(-)](i) results in membrane depolarisation following GABA(A) receptor activation, which is critical for various developmental processes including steroid-mediated sexual differentiation of the hypothalamus. Previously, we demonstrated that oestradiol enhances GABA-mediated Ca(2+) influx in neonate hypothalamus and that Ca(2+) induced activation of the transcription factor, cyclicAMP response element binding protein (CREB), was higher in male (high oestradiol) relative to female neonate hypothalamus. Based on these results, we hypothesised that expression of developmentally regulated chloride cotransporters may be sexually dimorphic. Here, we investigate the expression of the chloride cotransporters, NKCC1 (Na-K-2Cl(-)) and KCC2 (K-Cl(-)) in neonate mediobasal hypothalamus of male and female rats. The NKCC1 transporter moves Cl(-) into cells and helps maintain depolarising GABA action while the KCC2 transporter has the opposite effect by moving Cl(-) out of cells. NKCC1 mRNA levels were higher in males than females on the day of birth (postnatal day 0; PND 0) and total NKCC1 protein levels were significantly higher in males than females on embryonic day (ED) 20 and PND0. Levels of activated phosphorylated NKCC1 (pNKCC1) were not sexually dimorphic. Females were treated with a masculinising dose of oestradiol benzoate (EB; 100 microg; EB-females) on PND0. Total NKCC1 protein levels in tissue processed on PND1 and PND2 were similar in EB-females and oil-treated PND0 males and females. However, pNKCC1 protein levels measured on PND2 (but not PND1) were significantly higher in EB-treated females relative to oil-treated males and females. By contrast, KCC2 mRNA levels were significantly lower in males relative to females on PND0. KCC2 protein was not detectable on ED20 or PND0 but was significantly lower in males relative to females on PND5. These results suggest a complex relationship between KCC2 and NKCC1 mRNA and protein in developing brain that is not easily linked to regulation by oestradiol.

Multiple myeloma patients with CKS1B gene amplification have a shorter progression-free survival post-autologous stem cell transplantation

The prevalence and prognostic relevance of recurrent gains of CKS1B (cyclin kinase subunit 1B) gene at chromosome 1q21 region was investigated by interphase fluorescence in situ hybridisation in a cohort of 99 multiple myeloma (MM) patients treated with intensive chemotherapy followed by autologous stem cell transplantation. CKS1B amplification (3-8 CKS1B signals) was detected in 31of 99 (31%) patients and was associated with deletions of p53 (P = 0.003) and 13q (P = 0.039) but not with translocation t(11;14) or t(4;14). CKS1B amplification was associated with bone marrow plasmacytosis (P = 0.02), but there was no correlation with patient age, gender, disease stage, lytic bone lesions, albumin, creatinine, C-reactive protein or beta-2 microglobulin levels. Patients with CKS1B amplification had a significantly shorter progression-free survival than those without such amplification (18.5 vs. 25.7 months, P = 0.035). Likewise, a shorter overall survival (44.8 months vs. not reached) was observed; however, the difference did not reach statistical significance (P = 0.20). Seven patients had paired bone marrows obtained at diagnosis and at relapse, the percentage of cells with CKS1B amplification and the level of amplification were significantly increased in the relapse marrows. In this cohort of patients, CKS1B was frequently amplified in MM and may represent genetic instability associated with disease progression.

A statistical-based approach to assessing the fidelity of combinatorial libraries encoded with electrophoric molecular tags. Development and application of tag decode-assisted single bead LC/MS analysis

A statistical sampling protocol is described to assess the fidelity of libraries encoded with molecular tags. The methodology, termed library QA, is based on the combined application of tag decode analysis and single bead LC/MS. The physical existence of library compounds eluted from beads is established by comparing the molecular weight predicted by tag decode with empirical measurement. The goal of sampling is to provide information on overall library fidelity and an indication of the performance of individual library synthons. The minimal sampling size n for library QA is l0 x the largest synthon set. Data are reported as proportion (p) +/- lower and upper boundary (lb-ub) computed at the 95% confidence level (alpha = 0.05). As a practical demonstration, library QA was performed on a 25,200-member library of statine amides (size = 40 x 63 x 10). Sampling was conducted three times at n approximately 630 beads per run for a total of 1902 beads. The overall proportions found for the three runs were consistent with one another: p = 84.4%, lb-ub = 81.5-87.2%; p = 83.1%, lb-ub = 80.2-85.95; and p = 84.5%, lb-ub = 81.8-87.3%, suggesting the true value of p is close to 84% compound confirmation. The performance pi of individual synthons was also computed. Corroboration of QA data with biological screening results obtained from assaying the library against cathepsin D and plasmepsin II is discussed.

A paradigm for drug discovery employing encoded combinatorial libraries

Very large combinatorial libraries of small molecules on solid supports can now be synthesized and each library element can be identified after synthesis by using chemical tags. These tag-encoded libraries are potentially useful in drug discovery, and, to test this utility directly, we have targeted carbonic anhydrase (carbonate dehydratase; carbonate hydro-lyase, EC 4.2.1.1) as a model. Two libraries consisting of a total of 7870 members were synthesized, and structure-activity relationships based on the structures predicted by the tags were derived. Subsequently, an active representative of each library was resynthesized (2-[N-(4-sulfamoylbenzoyl)-4'-aminocyclohexanespiro]-4-oxo-7 -hydroxy- 2,3-dihydrobenzopyran and [N-(4-sulfamoylbenzoyl)-L-leucyl]piperidine-3-carboxylic acid) and these compounds were shown to have nanomolar dissociation constants (15 and 4 nM, respectively). In addition, a focused sublibrary of 217 sulfamoylbenzamides was synthesized and revealed a clear, testable structure-activity relationship describing isozyme-selective carbonic anhydrase inhibitors.

Complex synthetic chemical libraries indexed with molecular tags

Combinatorial methods of chemical synthesis allow the creation of molecular libraries having immense diversity. The utility of such libraries is dependent upon identifying the structures of the molecules so prepared. We describe the construction of a peptide combinatorial library, having 117,649 different members, synthesized on beads and indexed with inert chemical tags. These tags are used as a binary code to record the reaction history of each bead. The code can be read directly from a single bead by electron capture capillary gas chromatography. We demonstrate the correct selection of members of the library on the basis of binding to a monoclonal antibody.