MicroRNA 21a-5p overexpression impacts mediators of extracellular matrix formation in uterine leiomyoma.

BACKGROUND: MicroRNAs (MiR) may promote fibroid development via altered expression of genes involved in cell proliferation and ECM formation, and evidence supports aberrant expression of MicroRNA (MiR) 21a-5p in fibroids. The purpose of this study was to investigate the functional significance of MiR 21a-5p overexpression in the pathobiology of leiomyomata (fibroids). METHODS: A basic science experimental design using immortalized fibroid and myometrial cell lines derived from patient-matched specimens was used. Stable overexpression of MiR-21a-5p in an immortalized fibroid and patient matched myometrial cell line was achieved through lentiviral vector infection. Main outcome measures were MiR-21-5p overexpression, target gene and protein expression, collagen (COL1A1) production, cell proliferation, cell migration, and cell cycle stages of fibroid and myometrial immortalized cell lines. RESULTS: MiR-21a-5p was overexpressed to similar levels in fibroid and myometrial cell lines after lentiviral infection. Increased expression of miR-21 resulted in increased gene and protein expression of TGF-ß3 in both fibroid and myometrial cells. Changes in expression of the ECM genes Fibronectin, Collagen 1A1, CTGF, Versican and DPT were seen in both fibroid and myometrial cells. Changes were also seen in Matrix Metalloproteinase (MMP) related genes including MMP 2, MMP 9, MMP 11 and Serpine 1 in both fibroid and myometrial cells. MiR-21 upregulation resulted in increased proliferation and migration in fibroid cells compared to myometrial cells. CONCLUSIONS: MiR-21a-5p overexpression results in changes in the expression of ECM mediators in both fibroid and myometrial cells, and increased cell proliferation in fibroid cells. These finding suggest a potential functional role of MiR-21a-5p in the development of uterine fibroids and warrant further investigation.

Ridaforolimus improves the anti-tumor activity of dual HER2 blockade in uterine serous carcinoma in vivo models with HER2 gene amplification and PIK3CA mutation.

OBJECTIVE: Uterine serous carcinomas (USC) harbor simultaneous HER2 (ERBB2) over-expression and gain of function mutations in PIK3CA. These concurrent alterations may uncouple single agent anti-HER2 therapeutic efficacy making inhibition of the mammalian target of rapamycin (mTOR) a promising option to heighten anti-tumor response. METHODS: Both in vitro and in vivo experiments were conducted to assess proliferation, cell death and anti-tumor activity of ridaforolimus, lapatinib and combination lapatinib, trastuzumab (L/T) and ridaforolimus. With institutional approval, NOD/SCID mice bearing xenografts of non-immortalized, HER2 gene amplified cell lines (ARK1, ARK2) with and without PIK3CA gene mutations were divided into four arm cohorts. Ridaforolimus was administered alone and in combination with L/T. Tumor volumes were assessed and posttreatment analysis was performed. RESULTS: We observed dose dependent in vitro abrogation of downstream target proteins including phospho-AKT and phospho-S6. In both in vivo models, single agent ridaforolimus impaired xenograft tumor growth. Combination ridaforolimus and L/T, however, further improved the observed anti-tumor activity only in the ARK1 model with the PIK3CA gene mutation (E542K). The addition of mTOR inhibition to dual HER2 blockade added no additional anti-tumor effects in the ARK2 xenografts. Western blot and immunohistochemical analysis of downstream pathway alterations following in vivo treatment revealed dual HER2 blockade with ridaforolimus was necessary to induce apoptosis, decrease proliferation and abrogate phospho-S6 protein expression in the PIK3CA mutated model. CONCLUSIONS: These pilot data suggest that PIK3CA gene mutation may be an effective biomarker for selecting those HER2 over-expressing USC tumors most likely to benefit from mTOR inhibition.

The Therapeutic Challenge of Targeting HER2 in Endometrial Cancer.

UNLABELLED: Endometrial cancer is the most common gynecologic cancer in the United States, diagnosed in more than 50,000 women annually. While the majority of women present with low-grade tumors that are cured with surgery and adjuvant radiotherapy, a significant subset of women experience recurrence and do not survive their disease. A disproportionate number of the more than 8,000 annual deaths attributed to endometrial cancer are due to high-grade uterine cancers, highlighting the need for new therapies that target molecular alterations specific to this subset of tumors. Numerous correlative scientific investigations have demonstrated that the HER2 (ERBB2) gene is amplified in 17%-33% of carcinosarcoma, uterine serous carcinoma, and a subset of high-grade endometrioid endometrial tumors. In breast cancer, this potent signature has directed women to anti-HER2-targeted therapies such as trastuzumab and lapatinib. In contrast to breast cancer, therapy with trastuzumab alone revealed no responses in women with recurrent HER2 overexpressing endometrial cancer, suggesting that these tumors may possess acquired or innate trastuzumab resistance mechanisms. This review explores the literature surrounding HER2 expression in endometrial cancer, focusing on trastuzumab and other anti-HER2 therapy and resistance mechanisms characterized in breast cancer but germane to endometrial tumors. Understanding resistance pathways will suggest combination therapies that target both HER2 and key oncogenic escape pathways in endometrial cancer. IMPLICATIONS FOR PRACTICE: This review summarizes the role of HER2 in endometrial cancer, with a focus on uterine serous carcinoma. The limitations to date of anti-HER2 therapy in this disease site are examined, and mechanisms of drug resistance are outlined based on the experience in breast cancer. Potential opportunities to overcome inherent resistance to anti-HER2 therapy in endometrial cancer are detailed, offering opportunities for further clinical study with the goal to improve outcomes in this challenging disease.

HER2 over-expressing high grade endometrial cancer expresses high levels of p95HER2 variant.

BACKGROUND: Subsets of high grade endometrial cancer (EnCa) over-express HER2 (ERBB2), yet clinical trials have failed to demonstrate any anti-tumor activity utilizing trastuzumab, an approved platform for HER2 positive breast cancer (BrCa). A truncated p95HER2 variant lacking the trastuzumab binding site may confer resistance. The objective of this investigation was to characterize the expression of the p95HER2 truncated variant in EnCa. MATERIALS AND METHODS: With institutional approval, 86 high grade EnCa tumors were identified with tumor specimens from surgeries performed between 2000 and 2011. Clinical data were collected and all specimens underwent tumor genotyping, HER2 immunohistochemistry (IHC, HercepTest®), HER2 fluorescent in situ hybridization (FISH), along with total HER2 (H2T) and p95HER2 assessment with VeraTag® testing. Regression models were used to compare a cohort of 86 breast tumors selected for equivalent HER2 protein expression. RESULTS: We identified 44 high grade endometrioid and 42 uterine serous carcinomas (USC). IHC identified high HER2 expression (2+ or 3+) in 59% of the tumors. HER2 gene amplification was observed in 16 tumors (12 USC, 4 endometrioid). Both HER2 gene amplification and protein expression correlated with H2T values. High p95HER2 expression above 2.8RF/mm2 was observed in 53% (n=54) with significant correlation with H2T levels. When matched to a cohort of 107 breast tumors based on HercepTest HER2 expression, high grade EnCa presented with higher p95 levels (p<0.001). CONCLUSIONS: These data demonstrate that compared to BrCa, high grade EnCa expresses higher levels of p95HER2 possibly providing rationale for the trastuzumab resistance observed in EnCa.

Inhibition of gamma-secretase activity impedes uterine serous carcinoma growth in a human xenograft model.

OBJECTIVE: Uterine serous carcinoma (USC) represents an aggressive subtype of endometrial cancer. We sought to understand Notch pathway activity in USC and determine if pathway inhibition has anti-tumor activity. METHODS: Patient USC tissue blocks were obtained and used to correlate clinical outcomes with Notch1 expression. Three established USC cell lines were treated with gamma-secretase inhibitor (GSI) in vitro. Mice harboring cell line derived or patient derived USC xenografts (PDXs) were treated with vehicle, GSI, paclitaxel and carboplatin (P/C), or combination GSI and P/C. Levels of cleaved Notch1 protein and Hes1 mRNA were determined in GSI treated samples. Statistical analysis was performed using the Wilcoxon rank sum and Kaplan-Meier methods. RESULTS: High nuclear Notch1 protein expression was observed in 58% of USC samples with no correlation with overall survival. GSI induced dose-dependent reductions in cell number and decreased levels of cleaved Notch1 protein and Hes1 mRNA in vitro. Treatment of mice with GSI led to decreased Hes1 mRNA expression in USC xenografts. In addition, GSI impeded tumor growth of cell line xenografts as well as UT1 USC PDXs. When GSI and P/C were combined, synergistic anti-tumor activity was observed in UT1 xenografts. CONCLUSIONS: Notch1 is expressed in a large subset of USC. GSI-mediated Notch pathway inhibition led to both reduced cell numbers in vitro and decreased tumor growth of USC some xenograft models. When combined with conventional chemotherapy, GSI augmented anti-tumor activity in one USC PDX line suggesting that targeting of the Notch signaling pathway is a potential therapeutic strategy for future investigation.

Assessing the efficacy of targeting the phosphatidylinositol 3-kinase/AKT/mTOR signaling pathway in endometrial cancer.

OBJECTIVE: Alterations in the PI3K pathway are prevalent in endometrial cancer due to PIK3CA mutation and loss of PTEN. We investigated the anti-tumor activity of the PI3K inhibitor NVP BKM-120 (BKM) as a single agent and in combination with standard cytotoxic chemotherapy in a human primary endometrial xenograft model. METHODS: NOD/SCID mice bearing xenografts of primary human tumors with and without PIK3CA gene mutations were divided into two and four arm cohorts with equivalent tumor volumes. BKM was administered alone and in combination with paclitaxel and carboplatin (P/C) and endometrial xenograft tumor volumes were assessed. Tumors from the BKM, P/C, P/C+BKM and vehicle treated mice were processed for determination of PI3K/AKT/mTOR pathway activation. RESULTS: In both single agent experiments, BKM resulted in significant tumor growth suppression starting at days 5-10 compared to the linear growth observed in vehicle treated tumors (p<0.04 in all experiments). Tumor resurgence manifested between days 14 and 25 (p<0.03). When BKM was combined with P/C, this resistance pattern failed to develop in three separate xenograft lines (p<0.05). Synergistic tumor growth suppression (p<0.05) of only one xenograft tumor with no detected PIK3CA mutation was observed. Acute treatment with BKM led to a decrease in pAKT levels. CONCLUSION: Independent of PIK3CA gene mutation, BKM mediated inhibition of the PI3K/AKT/mTOR pathway in endometrial tumors precludes tumor growth in a primary xenograft model. While a pattern of resistance emerges, this effect appears to be mitigated by the addition of conventional cytotoxic chemotherapy.

Open access publishing - noble intention, flawed reality.

For two decades, the international scholarly publishing community has been embroiled in a divisive debate about the best model for funding the dissemination of scientific research. Some may assume that this debate has been thoroughly resolved in favour of the Open Access (OA) model of scientific publishing. Recent commentaries reveal a less settled reality. This narrative review aims to lay out the nature of these deep divisions among the sector's stakeholders, reflects on their systemic drivers and considers the future prospects for actualising OA's intended benefits and surmounting its risks and costs. In the process, we highlight some of inequities OA presents for junior or unfunded researchers, and academics from resource-poor environments, for whom an increasing body of evidence shows clear evidence of discrimination and injustice caused by Article Processing Charges. The authors are university-appointed researchers working the UK and South Africa, trained in disciplines ranging from medicine and epidemiology to social science and digital science. We have no vested interest in any particular model of scientific publication, and no conflicts of interest to declare. We believe the issues we identify are pertinent to almost all research disciplines.

Tissue-specific signatures of activating PIK3CA and RAS mutations in carcinosarcomas of gynecologic origin.

OBJECTIVES: Gynecologic carcinosarcoma is an aggressive malignancy that requires more effective treatment approaches. However, therapeutic implications regarding the specific gynecologic site of origin and the admixture of carcinomatous and sarcomatous elements that define this tumor remain uncertain. Therefore, broad genotyping was performed to identify tissue-specific somatic mutational profiles that may help direct targeted therapies in this complex neoplasia. METHODS: Genotyping was conducted on primary gynecologic carcinosarcomas arising from various disease sites (uterus, ovary, fallopian tube, vagina) and within isolated histological subcomponents. Nucleic acids extracted from diagnostic tissue were used in a genotyping platform that simultaneously queried >120 common mutations across 14 cancer genes. Mutational status was correlated with clinical variables using logistic regression and Kaplan-Meier survival estimates. RESULTS: Cancer gene mutations were identified in 46% of the 52 patient cohort and include TP53 (23%), PIK3CA (19%), KRAS (15%), CTNNB1 (4%) and NRAS (2%). Mutation in a single gene was observed in 31% of patient samples, while synchronous mutations involving 2 and 3 genes were noted in 13% and 2% of samples, respectively. Comparative evaluation of the carcinomatous and sarcomatous elements within a tumor demonstrated a similar mutation signature. Mutations in PIK3CA, KRAS and NRAS were exclusive to tumors of uterine origin and age-adjusted Cox proportional hazards modeling associated advanced age, stage and TP53 mutations with decreased survival in the uterine subset. CONCLUSION: While carcinosarcomas across gynecologic disease sites are histologically similar, therapeutically relevant mutations in the mitogen-activated protein kinase and phosphatidylinositol 3-kinase pathways predominated in carcinosarcomas arising in the uterus.

CD133 expression defines a tumor initiating cell population in primary human ovarian cancer.

Evidence is accumulating that solid tumors contain a rare phenotypically distinct population of cells, termed cancer stem cells (CSC), which give rise to and maintain the bulk of the tumor. These CSC are thought to be resistant to current chemotherapeutic strategies due to their intrinsic stem-like properties and thus may provide the principal driving force behind recurrent tumor growth. Given the high frequency of recurrent metastasis associated with human ovarian cancer, we sought to determine whether primary human ovarian tumors contain populations of cells with enhanced tumor-initiating capacity, a characteristic of CSC. Using an in vivo serial transplantation model, we show that primary uncultured human ovarian tumors can be reliably propagated in NOD/SCID mice, generating heterogeneous tumors that maintain the histological integrity of the parental tumor. The observed frequency of tumor engraftment suggests only certain subpopulations of ovarian tumor cells have the capacity to recapitulate tumor growth. Further profiling of human ovarian tumors for expression of candidate CSC surface markers indicated consistent expression of CD133. To determine whether CD133 expression could define a tumor-initiating cell population in primary human ovarian tumors, fluorescence-activated cell sorting (FACS) methods were employed. Injection of sorted CD133(+) and CD133(-) cell populations into NOD/SCID mice established that tumor-derived CD133(+) cells have an increased tumorigenic capacity and are capable of recapitulating the original heterogeneous tumor. Our data indicate that CD133 expression defines a NOD/SCID tumor initiating subpopulation of cells in human ovarian cancer that may be an important target for new chemotherapeutic strategies aimed at eliminating ovarian cancer.

Epigenetic regulation of CD133 and tumorigenicity of CD133 positive and negative endometrial cancer cells.

BACKGROUND: Recent data provide significant evidence to support the hypothesis that there are sub-populations of cells within solid tumors that have an increased tumor initiating potential relative to the total tumor population. CD133, a cell surface marker expressed on primitive cells of neural, hematopoietic, endothelial and epithelial lineages has been identified as a marker for tumor initiating cells in solid tumors of the brain, colon, pancreas, ovary and endometrium. Our objectives were to assess the relative level of CD133 expressing cells in primary human endometrial tumors, confirm their tumorigenic potential, and determine whether CD133 expression was epigenetically modified. METHODS: We assessed CD133 expression in primary human endometrial tumors by flow cytometry and analyzed the relative tumorigenicity of CD133+ and CD133- cells in an in vivo NOD/SCID mouse model. We assessed potential changes in CD133 expression over the course of serial transplantation by immunofluorescence and flow cytometry. We further examined CD133 promoter methylation and expression in normal endometrium and malignant tumors. RESULTS: As determined by flow cytometric analysis, the percentage of CD133+ cells in primary human endometrial cancer samples ranged from 5.7% to 27.4%. In addition, we confirmed the tumor initiating potential of CD133+ and CD133- cell fractions in NOD/SCID mice. Interestingly, the percentage of CD133+ cells in human endometrial tumor xenografts, as evidenced by immunofluorescence, increased with serial transplantation although this trend was not consistently detected by flow cytometry. We also determined that the relative levels of CD133 increased in endometrial cancer cell lines following treatment with 5-aza-2'-deoxycytidine suggesting a role for methylation in the regulation of CD133. To support this finding, we demonstrated that regions of the CD133 promoter were hypomethylated in malignant endometrial tissue relative to benign control endometrial tissue. Lastly, we determined that methylation of the CD133 promoter decreases over serial transplantation of an endometrial tumor xenograft. CONCLUSIONS: These findings support the hypotheses that CD133 expression in endometrial cancer may be epigenetically regulated and that cell fractions enriched for CD133+ cells may well contribute to endometrial cancer tumorigenicity, pathology and recurrence.

Monozygotic twins discordant for neurofibromatosis 1.

We present monozygotic twins discordant for the autosomal dominant disorder neurofibromatosis type 1 (NF1). The affected twin was diagnosed with NF1 at age 12, based upon accepted clinical criteria for the disorder. Both twins were re-examined at ages 35 and 57, at which times the unaffected twin continued to show no clinical manifestations of NF1. Short tandem repeat marker (STR) genotyping at 10 loci on chromosome 17 and 10 additional loci dispersed across the genome revealed identical genotypes for the twins, confirming their monozygosity. The affected twin has three children, two of whom also have NF1, while the unaffected twin has two children, both unaffected. Using lymphoblastoid, fibroblast, and buccal cell samples collected from both twins and from other family members in three generations, we discovered a pathogenic nonsense mutation in exon 40 of the NF1 gene. This mutation was found in all cell samples from the affected twin and her affected daughter, and in lymphoblastoid and buccal cells but not fibroblasts from the unaffected twin. We also found a novel non-synonymous change in exon 16 of the NF1 gene that was transmitted from the unaffected mother to both twins and co-segregated with the pathogenic mutation in the ensuing generation. All cells from the twins were heterozygous for this apparent exon 16 polymorphism and for single nucleotide polymorphisms (SNPs) within 2.5 kb flanking the site of the exon 40 nonsense mutation. This suggests that the NF1 gene of the unaffected twin differed in the respective lymphoblastoid cells and fibroblasts only at the mutation site itself, making post-zygotic mutation leading to mosaicism the most likely mechanism of phenotypic discordance. Although the unaffected twin is a mosaic, the distribution of the mutant allele among different cells and tissues appears to be insufficient to cause overt clinical manifestations of NF1.

Monitoring diseases across borders: African regional integrative information systems.

In African countries, communicable diseases remain the chief cause of a heavy disease burden. Regional economic, political and social integration bring new challenges in the management of these diseases, many of which are treatable. Information Communication Technology (ICT) applied through electronic health systems has the potential to strengthen healthcare service delivery and disease surveillance within these countries. This paper discusses the importance of well-defined e-Health strategies within countries and, in addition, proposes that countries within regions collaborate in planning for health information exchange across borders. It is suggested that particular attention be paid to technical and data standards enabling interoperability, and also to issues of security, patient privacy and governance.

Transient commensal clonal interactions can drive tumor metastasis.

The extent and importance of functional heterogeneity and crosstalk between tumor cells is poorly understood. Here, we describe the generation of clonal populations from a patient-derived ovarian clear cell carcinoma model which forms malignant ascites and solid peritoneal tumors upon intraperitoneal transplantation in mice. The clonal populations are engineered with secreted Gaussia luciferase to monitor tumor growth dynamics and tagged with a unique DNA barcode to track their fate in multiclonal mixtures during tumor progression. Only one clone, CL31, grows robustly, generating exclusively malignant ascites. However, multiclonal mixtures form large solid peritoneal metastases, populated almost entirely by CL31, suggesting that transient cooperative interclonal interactions are sufficient to promote metastasis of CL31. CL31 uniquely harbors ERBB2 amplification, and its acquired metastatic activity in clonal mixtures is dependent on transient exposure to amphiregulin, which is exclusively secreted by non-tumorigenic clones. Amphiregulin enhances CL31 mesothelial clearance, a prerequisite for metastasis. These findings demonstrate that transient, ostensibly innocuous tumor subpopulations can promote metastases via "hit-and-run" commensal interactions.

The Metabolic Inhibitor CPI-613 Negates Treatment Enrichment of Ovarian Cancer Stem Cells.

One of the most significant therapeutic challenges in the treatment of ovarian cancer is the development of recurrent platinum-resistant disease. Cancer stem cells (CSCs) are postulated to contribute to recurrent and platinum-resistant ovarian cancer (OvCa). Drugs that selectively target CSCs may augment the standard of care cytotoxics and have the potential to prevent and/or delay recurrence. Increased reliance on metabolic pathway modulation in CSCs relative to non-CSCs offers a possible therapeutic opportunity. We demonstrate that treatment with the metabolic inhibitor CPI-613 (devimistat, an inhibitor of tricarboxylic acid (TCA) cycle) in vitro decreases CD133+ and CD117+ cell frequency relative to untreated OvCa cells, with negligible impact on non-CSC cell viability. Additionally, sphere-forming capacity and tumorigenicity in vivo are reduced in the CPI-613 treated cells. Collectively, these results suggest that treatment with CPI-613 negatively impacts the ovarian CSC population. Furthermore, CPI-613 impeded the unintended enrichment of CSC following olaparib or carboplatin/paclitaxel treatment. Collectively, our results suggest that CPI-613 preferentially targets ovarian CSCs and could be a candidate to augment current treatment strategies to extend either progression-free or overall survival of OvCa.

PARP Inhibition Induces Enrichment of DNA Repair-Proficient CD133 and CD117 Positive Ovarian Cancer Stem Cells.

PARP inhibitors (PARPi) are FDA-approved monotherapy agents for the treatment of recurrent ovarian cancer in patients with and without a BRCA mutation. Despite promising response rates, not all patients derive benefit, and the majority develop resistance. PARPi treatment in vitro and in vivo induced an enrichment of CD133+ and CD117+ ovarian cancer stem cells (CSC). This effect was not affected by BRCA mutation status. In the CSC fractions, PARPi induced cell-cycle arrest in G2-M with a consequent accumulation of γH2AX, RAD51, and uniquely DMC1 foci. DNA damage and repair monitoring assays demonstrated that CSCs display more efficient DNA repair due, in part, to activation of embryonic repair mechanisms which involved the RAD51 homologue, DMC1 recombinase. Preserved and induced homologous repair (HR) could be a mechanism of an inherent resistance of CSCs to the synthetic lethality of PARPi that likely promotes disease recurrence. IMPLICATIONS: Treatment with PARPi fails to significantly affect ovarian cancer CSC populations, likely contributing to recurrent disease. Ovarian cancer CSCs stabilize genomic integrity after PARPi treatment, due to a more efficient inherent DNA repair capacity. PARPi-induced DMC1 recombinase and HR proficiency provide CSCs the opportunity to repair DNA damage more efficiently.Visual Overview: http://mcr.aacrjournals.org/content/molcanres/17/2/431/F1.large.jpg.

Treatment of ovarian cancer by targeting the tumor stem cell-associated carbohydrate antigen, Sialyl-Thomsen-nouveau.

Recurrent ovarian cancer (OvCa) is thought to result in part from the inability to eliminate rare quiescent cancer stem cells (CSCs) that survive cytotoxic chemotherapy and drive tumor resurgence. The Sialyl-Thomsen-nouveau antigen (STn) is a carbohydrate moiety present on protein markers of CSCs in pancreatic, colon, and gastric malignancies. We have demonstrated that human OvCa cell lines contain varying levels of cells that independently express either STn or the ovarian CSC marker CD133. Here we determine co-expression of STn and CD133 in a subset of human OvCa cell lines. Analyses of colony and sphere forming capacity and of response to standard-of-care cytotoxic therapy suggest a subset of OvCa STn+ cells display some CSC features. The effect of the anti-STn antibody-drug conjugates (ADCs) S3F-CL-MMAE and 2G12-2B2-CL-MMAE on OvCa cell viability in vitro and in vivo was also assessed. Treatment with S3F-CL-MMAE reduced the viability of two of three OvCa cell lines in vitro and exposure to either S3F-CL-MMAE or 2G12-2B2-CL-MMAE reduced OVCAR3-derived xenograft volume in vivo, depleting STn+ tumor cells. In summary, STn+ cells demonstrate some stem-like properties and specific therapeutic targeting of STn in ovarian tumors may be an effective clinical strategy to eliminate both STn+ CSC and STn+ non-CSC populations.

SD-1029 inhibits signal transducer and activator of transcription 3 nuclear translocation.

PURPOSE: Signal transducer and activator of transcription 3 (Stat3) proteins have important roles in cancer cell survival and proliferation. Recent studies show that aberrant Stat3 activation promotes tumor growth and survival in several human cancers, and thus, presents an attractive pathway for the development of targeted anticancer therapy. Stat3 is a DNA-binding transcription factor, and thus, its function depends on cytoplasmic to nuclear translocation. To discover novel inhibitors of the Stat3 signaling pathway, we designed a cell-based screening assay capable of identifying compounds that inhibit Stat3 nuclear translocation and activity. EXPERIMENTAL DESIGN: Cell-based fluorescence microscope screening and quantitative measurement of enhanced green fluorescent protein-Stat3 nuclear translocation assays were used to identify novel Stat3 inhibitors. The effects of identified Stat3 inhibitors on Janus kinase (Jak), Stat3 expression, and activation were determined by Western blotting and kinase in vitro autophosphorylation assay. The effects of identified Stat3 inhibitors on cell growth was evaluated by cell proliferation assay and apoptosis assay. RESULTS: Among the National Cancer Institute Diversity set, a 2,000-member library of bioactive small molecules, we identified SD-1029 as a micromolar inhibitor of IL-6 or oncostatin-induced Stat3 nuclear translocation. Biochemical analysis shows that SD-1029 inhibits tyrosyl phosphorylation of Stat3 implicating SD-1029 as an inhibitor of Jak. Further analysis shows that this compound inhibits tyrosyl phosphorylation of the Jak2 isoenzyme. The antiapoptotic proteins Bcl-X(L) and survivin, target proteins of activated Stat3, are down-regulated by SD-1029 resulting in the induction of apoptosis in several human breast and ovarian cancer cell lines. SD-1029 also enhances apoptosis induced by paclitaxel in ovarian cancer cells. CONCLUSIONS: These results show that SD-1029 directly abrogates the Jak-Stat3 signaling pathway in human cancer cells expressing constitutively active Stat, and add to the growing literature that validates this pathway as a viable target for further drug development. Finally, SD-1029 may represent a suitable prototype for structural optimization and exploration as a therapeutic lead.

Signal transducers and activators of transcription 3 pathway activation in drug-resistant ovarian cancer.

PURPOSE: One of the major obstacles in the treatment of ovarian cancer is the development of multidrug resistance. Recent evidence shows that high-grade ovarian cancer often shows activation of the signal transducers and activators of transcription 3 (Stat3) pathway with subsequent transcription of genes that support tumor growth and survival. Less studied is the role of the Stat3 pathway in acquired drug resistance. There is no information on Stat3 expression in chemotherapy naïve ovarian cancer as compared with tumors collected later in the natural history of the disease. To further clarify the significance of Stat3 activation in ovarian cancer, here we investigated the Stat3 expression and activation in ovarian cancer and ovarian cancer multidrug resistance cell lines. EXPERIMENTAL DESIGN: Western blotting, electrophoretic mobility shift assay, luciferase assays, ELISA assay, and real-time reverse transcription-PCR determined interleukin-6 and Stat3 pathway expression and activation in cell lines. Stat3 expression in ovarian cancer tissue microarray was evaluated by immunohistochemistry. RESULTS: Activated (phosphorylated) Stat3 is overexpressed in most paclitaxel-resistant ovarian cancer cells. Inhibition of Stat3 activation results in significant decreases in paclitaxel resistance and enhanced apoptosis. Drug-resistant recurrent tumors have significantly greater phosphorylated Stat3 (pStat3) expression as compared with matched primary tumors. Tumors with associated inflammatory cell infiltrates also have a higher proportion of cells staining intensely for nuclear phosphorylated Stat3 as compared with tumors without inflammatory infiltrates, consistent with paracrine activation of the Stat3 pathway by immune-mediated cytokines. CONCLUSIONS: These data support the hypothesis that interruption of Stat3 signaling could reverse resistance to paclitaxel and perhaps other chemotherapy agents in human cancer.

Immunisation coverage of Queensland indigenous two-year-old children by cluster sampling and by register.

OBJECTIVES: To obtain, through a survey, estimates of immunisation coverage in a birth cohort of Indigenous children, and to compare survey estimates with those obtained from the Australian Childhood Immunisation Register (ACIR) for the same birth cohort of Indigenous children. METHODS: Cluster sampling of a birth cohort of two-year-old Indigenous children across Queensland, stratified according to accessibility/remoteness from services, was undertaken in 2003. An innovative method of identifying participants was used. Survey results of 10 vaccine doses were compared with ACIR data. RESULTS: The survey obtained a 4% sample of the birth cohort (137 children). Universally recommended vaccines showed high levels of coverage at 12 and 24 months, and survey estimates were slightly higher than ACIR estimates. Diphtheria-tetanus-acellular pertussis vaccine dose 3 (DTPa3) coverage was 93.8% (95% CI 88.0-99.6) by 12 months on survey and 87.5% on ACIR. Coverage was not timely and a lag phase of 4-6 months occurred for each vaccine dose. Haemophilus influenzae type b vaccine dose 2 (Hib2), scheduled for the age of four months, reached 90% coverage by nine months of age in the survey children. CONCLUSION: Both methods reported here provided similar results. IMPLICATIONS: These data indicate that ACIR Indigenous reporting rates have increased and coverage estimates are comparable to those provided by a survey. Immunisation coverage appears to be high, and the main remaining challenge in further reducing vaccine-preventable disease in Indigenous children is to improve immunisation timeliness.

Chemosensitization to cisplatin by inhibitors of the Fanconi anemia/BRCA pathway.

Cisplatin resistance occurs, at least in part, through the function of the Fanconi anemia (FA)/BRCA pathway, a DNA-damage response pathway required for repair of cisplatin cross-links. In the current study, we designed a cell-based screening strategy to identify small-molecule inhibitors of the FA/BRCA pathway with the hypothesis that such molecules could restore sensitivity to platinum agents. We identified four inhibitors, including three protein kinase inhibitors (wortmannin, H-9, and alsterpaullone) and one natural compound (curcumin) that inhibit the FA/BRCA pathway. We show that curcumin, a compound that is generally regarded as safe, inhibits the monoubiquitination of the FANCD2 protein as predicted by the screen and consequently sensitizes ovarian and breast tumor cell lines to cisplatin through apoptotic cell death. We believe that this study shows an efficient, high-throughput method for identifying new compounds that may sensitize cancer cells to DNA-damaging chemotherapy.