Predictive and prognostic biomarkers in female genital tract tumours: an update highlighting their clinical relevance and practical issues

The evaluation of biomarkers by molecular techniques and immunohistochemistry has become increasingly relevant to the treatment of female genital tract tumours as a consequence of the greater availability of therapeutic options and updated disease classifications. For ovarian cancer, mutation testing for BRCA1/2 is the standard predictive biomarker for poly(ADP-ribose) polymerase inhibitor therapy, while homologous recombination deficiency testing may allow the identification of eligible patients among cases without demonstrable BRCA1/2 mutations. Clinical recommendations are available which specify how these predictive biomarkers should be applied. Mismatch repair (MMR) protein and folate receptor alpha immunohistochemistry may also be used to guide treatment in ovarian cancer. In endometrial cancer, MMR immunohistochemistry is the preferred test for predicting benefit from immune checkpoint inhibitor (ICI) therapy, but molecular testing for microsatellite instability may have a supplementary role. HER2 testing by immunohistochemistry and in situ hybridisation is applicable to endometrial serous carcinomas to assess trastuzumab eligibility. Immunohistochemistry for oestrogen receptor and progesterone receptor expression may be used for prognostication in endometrial cancer, but its predictive value for hormonal therapy is not yet proven. POLE mutation testing and p53 immunohistochemistry (as a surrogate for TP53 mutation status) serve as prognostic markers for favourable and adverse outcomes, respectively, in endometrial cancer, especially when combined with MMR testing for molecular subtype designation. For cervical cancer, programmed death ligand 1 immunohistochemistry may be used to predict benefit from ICI therapy although its predictive value is under debate. In vulvar cancer, p16 and p53 immunohistochemistry has established prognostic value, stratifying patients into three groups based on the human papillomavirus and TP53 mutation status of the tumour. Awareness of the variety and pitfalls of expression patterns for p16 and p53 in vulvar carcinomas is crucial for accurate designation. It is hoped that collaborative efforts in standardising and optimising biomarker testing for gynaecological tumours will contribute to evidence-based therapeutic decisions.

Evaluation of an Isothermal Amplification HPV Assay on Self-Collected Vaginal Samples as Compared to Clinician-Collected Cervical Samples

This study aimed to evaluate the concordance of HPV results between the SentisTM HPV assay (Sentis) (BGI Group, Shenzhen, China), an isothermal amplification-based HPV assay, on self-collected and clinician-collected samples and the agreement of Sentis on self-collected samples with the BD OnclarityTM HPV assay (Onclarity) (Becton, Dickinson, and Company, Franklin Lakes, New Jersey, USA), a PCR-based HPV assay, on clinician-collected samples. This was a prospective study of 104 women attending the colposcopy clinic for abnormal smears. After informed consent, participants self-collected vaginal samples before having clinician-collected cervical samples. Self-collected samples underwent HPV testing with Sentis (Self-Sentis HPV) and clinician-collected samples were tested with Sentis (Clinician-Sentis HPV) and Onclarity (Clinician-Onclarity), which was used as a reference standard. The concordance was assessed using Cohen's kappa. The prevalence of HPV and the acceptability of self-sampling were also evaluated. The concordance rate between Self-Sentis HPV and Clinician-Sentis HPV was 89.8% with a kappa of 0.769. The concordance rate between Self-Sentis HPV and Clinician-Onclarity was 84.4% with a kappa of 0.643. The prevalence of HPV was 26.0% on Clinician-Onclarity, 29.3% on Clinician-Sentis HPV, and 35.6% on Self-Sentis HPV. Overall, 65% of participants would undergo self-sampling again. This was attributed to mainly not feeling embarrassed (68%) and being convenient (58%). Our study showed a substantial agreement between Self-Sentis HPV with Clinician-Sentis HPV and Clinician-Onclarity. Self-sampling was also shown to be a generally well-accepted method of screening.

Clinical performance of the Roche Cobas 4800 HPV test for primary cervical cancer screening in a Chinese population

High-risk human papillomavirus (HR-HPV) testing has become an increasing important strategy in primary cervical cancer screening in recent years. It warrants the evaluation of molecular-based HPV tests for accuracy and efficacy of screening. The performance of Roche Cobas 4800 HPV test was validated and compared with Digene Hybrid Capture 2 (HC2) high-risk HPV DNA test for primary screening in a large Chinese screening cohort. Of 6345 women screened, overall agreement between Cobas and HC2 was 92.23% (95% CI: 91.57–92.89). The inter-assay agreement was correlated with the severity of underlying biology, with an increasing concordance found in samples with more severe abnormalities. Most of the discordant samples had the test signal strength closer to the test limits of the detection than concordant samples, reflecting a low viral load and infection of a cluster of low-risk HPV in these samples. The Cobas test demonstrated significantly higher specificity in identifying CIN2+/CIN3+ cases than HC2 test (66.46% vs 43.67% and 65.42% vs 42.86%, p<0.001), with comparable sensitivity in clinical evaluation. Increased specificity of Cobas test would accent women having the highest risk of developing CIN2+, with the potential to reduce unnecessary colposcopy referral in a screening population.

PFKFB3 Regulates Chemoresistance, Metastasis and Stemness via IAP Proteins and the NF-κB Signaling Pathway in Ovarian Cancer

Glycolysis has been reported to be critical for cancer stem cells (CSCs), which are associated with tumor chemoresistance, metastasis and recurrence. Thus, selectively targeting glycolytic enzymes may be a potential therapy for ovarian cancer. 6‐phosphofructo‐2‐kinase/fructose‐2,6‐biphosphatase 3 (PFKFB3), the main source of fructose-2,6-bisphosphate, controls the first committed step in glycolysis. We investigate the clinical significance and roles of PFKFB3 in ovarian cancer using in vitro and in vivo experiments. We demonstrate that PFKFB3 is widely overexpressed in ovarian cancer and correlates with advanced stage/grade and poor outcomes. Significant up-regulation of PFKFB3 was found in ascites and metastatic foci, as well as CSC-enriched tumorspheres and ALDH+CD44+ cells. 3PO, a PFKFB3 inhibitor, reduced lactate level and sensitized A2780CP cells to cisplatin treatment, along with the modulation of inhibitors of apoptosis proteins (c-IAP1, c-IAP2 and survivin) and an immune modulator CD70. Blockade of PFKFB3 by siRNA approach in the CSC-enriched subset led to decreases in glycolysis and CSC properties, and activation of the NF-κB cascade. PFK158, another potent inhibitor of PFKFB3, impaired the stemness of ALDH+CD44+ cells in vitro and in vivo, whereas ectopic expression of PFKFB3 had the opposite results. Overall, PFKFB3 was found to mediate metabolic reprogramming, chemoresistance, metastasis and stemness in ovarian cancer, possibly via the modulation of inhibitors of apoptosis proteins and the NF-κB signaling pathway; thus, suggesting that PFKFB3 may be a potential therapeutic target for ovarian cancer.

Targeting DNA Damage Response Pathway in Ovarian Clear Cell Carcinoma

Ovarian clear cell carcinoma (OCCC) is one of the major types of ovarian cancer and is of higher relative prevalence in Asians. It also shows higher possibility of resistance to cisplatin-based chemotherapy leading to poor prognosis. This may be attributed to the relative lack of mutations and aberrations in homologous recombination-associated genes, which are crucial in DNA damage response (DDR), such as BRCA1, BRCA2, p53, RAD51, and genes in the Fanconi anemia pathway. On the other hand, OCCC is characterized by a number of genetic defects rendering it vulnerable to DDR-targeting therapy, which is emerging as a potent treatment strategy for various cancer types. Mutations of ARID1A, PIK3CA, PTEN, and catenin beta 1 (CTNNB1), as well as overexpression of transcription factor hepatocyte nuclear factor-1β (HNF-1β), and microsatellite instability are common in OCCC. Of particular note is the loss-of-function mutations in ARID1A, which is found in approximately 50% of OCCC. ARID1A is crucial for processing of DNA double-strand break (DSB) and for sustaining DNA damage signaling, rendering ARID1A-deficient cells prone to impaired DNA damage checkpoint regulation and hence sensitive to poly ADP ribose polymerase (PARP) inhibitors. However, while preclinical studies have demonstrated the possibility to exploit DDR deficiency in OCCC for therapeutic purpose, progress in clinical application is lagging. In this review, we will recapitulate the preclinical studies supporting the potential of DDR targeting in OCCC treatment, with emphasis on the role of ARID1A in DDR. Companion diagnostic tests (CDx) for predicting susceptibility to PARP inhibitors are rapidly being developed for solid tumors including ovarian cancers and may readily be applicable on OCCC. The potential of various available DDR-targeting drugs for treating OCCC by drawing analogies with other solid tumors sharing similar genetic characteristics with OCCC will also be discussed.

Strategic Combination Therapies for Ovarian Cancer

Ovarian cancer remains the leading cause of gynecologic cancer-related deaths among women worldwide. The dismal survival rate is partially due to recurrence after standardized debulking surgery and first-line chemotherapy. In recent years, targeted therapies, including antiangiogenic agents or poly (ADP-ribose) polymerase inhibitors, represent breakthroughs in the treatment of ovarian cancer. As more therapeutic agents become available supplemented by a deeper understanding of ovarian cancer biology, a range of combination treatment approaches are being actively investigated to further improve the clinical outcomes of the disease. These combinations, which involve DNA-damaging agents, targeted therapies of signaling pathways and immunotherapies, simultaneously target multiple cancer pathways or hallmarks to induce additive or synergistic antitumor activities. Here we review the preclinical data and ongoing clinical trials for developing effective combination therapies in treating ovarian cancer. These emerging therapeutic modalities may reshape the treatment landscape of the disease.

Nuclear HKII-P-p53 (Ser15) Interaction is a Prognostic Biomarker for Chemoresponsiveness and Glycolytic Regulation in Epithelial Ovarian Cancer

Simple Summary

Hexokinase II (HKII) is a key glycolysis enzyme associated with tumorigenesis, but its molecular mechanism and pathophysiological role in chemoresistant ovarian cancer remain elusive. In this study, we delineate the novel mechanism showing that activated phosphorylated-p53 (P-p53 Ser15) is required for the regulation of HKII intracellular trafficking and metabolic regulation in chemosensitive ovarian cancer, but not in chemoresistant ovarian cancer harboring p53 mutation. We have observed that increased nuclear HKII-P-p53 (Ser15) interaction is likely associated with chemosensitivity and better survival outcomes in epithelial ovarian cell lines, human primary epithelial ovarian cancer cells, and tumor sections. Nuclear HKII-P-p53 (Ser15) interaction may function as a promising prognostic biomarker, enabling prediction of patients with poor prognosis for deciding better clinical strategies.

Abstract

In epithelial ovarian cancer (EOC), carboplatin/cisplatin-induced chemoresistance is a major hurdle to successful treatment. Aerobic glycolysis is a common characteristic of cancer. However, the role of glycolytic metabolism in chemoresistance and its impact on clinical outcomes in EOC are not clear. Here, we show a functional interaction between the key glycolytic enzyme hexokinase II (HKII) and activated P-p53 (Ser15) in the regulation of bioenergetics and chemosensitivity. Using translational approaches with proximity ligation assessment in cancer cells and human EOC tumor sections, we showed that nuclear HKII-P-p53 (Ser15) interaction is increased after chemotherapy, and functions as a determinant of chemoresponsiveness as a prognostic biomarker. We also demonstrated that p53 is required for the intracellular nuclear HKII trafficking in the control of glycolysis in EOC, associated with chemosensitivity. Mechanistically, cisplatin-induced P-p53 (Ser15) recruits HKII and apoptosis-inducing factor (AIF) in chemosensitive EOC cells, enabling their translocation from the mitochondria to the nucleus, eliciting AIF-induced apoptosis. Conversely, in p53-defective chemoresistant EOC cells, HKII and AIF are strongly bound in the mitochondria and, therefore, apoptosis is suppressed. Collectively, our findings implicate nuclear HKII-P-p53(Ser15) interaction in chemosensitivity and could provide an effective clinical strategy as a promising biomarker during platinum-based therapy.

MicroRNA-135a-induced formation of CD133+ subpopulation with cancer stem cell properties in cervical cancer

Cancer stem cells (CSCs) play significant roles in tumor initiation. MicroRNA-135a (miR-135a) induced the formation of a CD133+ subpopulation from a human papillomavirus-immortalized cervical epithelial cell line. Compared with the CD133- cells, the CD133+ cells expressed higher levels of miR-135a and OCT4, exhibited significantly higher tumorsphere forming capacity and the time required for tumorsphere formation was shortened in the second generation. Serum induction suppressed the expression of CD133, OCT4 and miR-135a, but increased expression of involucrin in the miR-135a-induced CD133+ cells. The miR-135a-induced CD133+ cells were tumorigenic in a limiting dilution approach in vivo. The cells expressed significantly higher level of active β-catenin and OCT4 than the CD133- counterpart. Wnt3a enhanced the expression of OCT4 and CD133 in cervical cancer cells but failed to enhance CD133 transcription in normal cervical cells. Wnt3a stimulation also increased tumorsphere size and self-renewal of miR-135a-induced CD133+ subpopulation. Wnt/β-catenin inhibition suppressed tumorsphere formation while Wnt3a partially nullified the inhibitory effect. Taken together, miR-135a induced the formation of a subpopulation of cells with CSC properties both in vitro and in vivo and the Wnt/β-catenin signaling pathway is essential to maintain its tumorigenicity.

SENP1-mediated deSUMOylation of JAK2 regulates its kinase activity and platinum drug resistance

The JAK2/STAT pathway is hyperactivated in many cancers, and such hyperactivation is associated with a poor clinical prognosis and drug resistance. The mechanism regulating JAK2 activity is complex. Although translocation of JAK2 between nucleus and cytoplasm is an important regulatory mechanism, how JAK2 translocation is regulated and what is the physiological function of this translocation remain largely unknown. Here, we found that protease SENP1 directly interacts with and deSUMOylates JAK2, and the deSUMOylation of JAK2 leads to its accumulation at cytoplasm, where JAK2 is activated. Significantly, this novel SENP1/JAK2 axis is activated in platinum-resistant ovarian cancer in a manner dependent on a transcription factor RUNX2 and activated RUNX2/SENP1/JAK2 is critical for platinum-resistance in ovarian cancer. To explore the application of anti-SENP1/JAK2 for treatment of platinum-resistant ovarian cancer, we found SENP1 deficiency or treatment by SENP1 inhibitor Momordin Ic significantly overcomes platinum-resistance of ovarian cancer. Thus, this study not only identifies a novel mechanism regulating JAK2 activity, but also provides with a potential approach to treat platinum-resistant ovarian cancer by targeting SENP1/JAK2 pathway.

p85β regulates autophagic degradation of AXL to activate oncogenic signaling

PIK3R2 encodes the p85β regulatory subunit of phosphatidylinositol 3-kinase and is frequently amplified in cancers. The signaling mechanism and therapeutic implication of p85β are poorly understood. Here we report that p85β upregulates the protein level of the receptor tyrosine kinase AXL to induce oncogenic signaling in ovarian cancer. p85β activates p110 activity and AKT-independent PDK1/SGK3 signaling to promote tumorigenic phenotypes, which are all abolished upon inhibition of AXL. At the molecular level, p85β alters the phosphorylation of TRIM2 (an E3 ligase) and optineurin (an autophagy receptor), which mediate the selective regulation of AXL by p85β, thereby disrupting the autophagic degradation of the AXL protein. Therapeutically, p85β expression renders ovarian cancer cells vulnerable to inhibitors of AXL, p110, or PDK1. Conversely, p85β-depleted cells are less sensitive to these inhibitors. Together, our findings provide a rationale for pharmacological blockade of the AXL signaling axis in PIK3R2-amplified ovarian cancer.

Primary HPV testing with cytology versus cytology alone in cervical screening-A prospective randomized controlled trial with two rounds of screening in a Chinese population

We conducted a prospective randomized controlled trial with two screening rounds to evaluate the effectiveness of combining HPV testing with liquid-based cytology (LBC) as a co-test, compared to LBC only in cervical cancer screening of a Chinese population. First, 15,955 women aged 30-60 were randomized at a 1:1 ratio into an intervention group (Digene Hybrid Capture 2 HPV test with LBC) and a control group (LBC alone). Women in the intervention group would be referred for colposcopy and biopsy immediately if they were found to have high-risk HPV regardless of cytology results. The detection of cervical intraepithelial neoplasia grade 2 or above (CIN2+) lesions was significantly higher in the intervention group compared to the control (0.95% vs. 0.38%, OR 2.50, 95% CI 1.65-3.88). At the subsequent round of screening approximately 36 months later, CIN2+ detection was significantly lower in the intervention group (0.08% vs. 0.35%, OR 0.23, 95% CI 0.08-0.57). Over the two rounds of screening, the total detection of CIN2+ was higher in the intervention group (1.01% vs. 0.66%, OR 1.53, 95% CI 1.09-2.19). There was a fourfold increase (10.6% vs. 2.4%, p < 0.001) in the number of colposcopies performed in the intervention arm. Adding a high-risk HPV test to cytology for primary cervical screening led to earlier detection of clinically significant preinvasive lesions, resulting in a reduced detection of CIN2+ lesions in subsequent rounds and an increased rate of colposcopy.

ERK Regulates HIF1α-Mediated Platinum Resistance by Directly Targeting PHD2 in Ovarian Cancer

PURPOSE

Up to 80% of patients with ovarian cancer develop platinum resistance over time to platinum-based chemotherapy. Increased HIF1α level is an important mechanism governing platinum resistance in platinum-resistant ovarian cancer (PROC). However, the mechanism regulating HIF1α stability in PROC remains largely unknown. Here, we elucidate the mechanism of HIF1α stability regulation in PROC and explore therapeutic approaches to overcome cisplatin resistance in ovarian cancer.

EXPERIMENTAL DESIGN

We first used a quantitative high-throughput combinational screen (qHTCS) to identify novel drugs that could resensitize PROC cells to cisplatin. Next, we evaluated the combination efficacy of inhibitors of HIF1α (YC-1), ERK (selumetinib), and TGFβ1 (SB431542) with platinum drugs by in vitro and in vivo experiments. Moreover, a novel TGFβ1/ERK/PHD2-mediated pathway regulating HIF1α stability in PROC was discovered.

RESULTS

YC-1 and selumetinib resensitized PROC cells to cisplatin. Next, the prolyl hydroxylase domain-containing protein 2 (PHD2) was shown to be a direct substrate of ERK. Phosphorylation of PHD2 by ERK prevents its binding to HIF1α, thus inhibiting HIF1α hydroxylation and degradation-increasing HIF1α stability. Significantly, ERK/PHD2 signaling in PROC cells is dependent on TGFβ1, promoting platinum resistance by stabilizing HIF1α. Inhibition of TGFβ1 by SB431542, ERK by selumetinib, or HIF1α by YC-1 efficiently overcame platinum resistance both in vitro and in vivo. The results from clinical samples confirm activation of the ERK/PHD2/HIF1α axis in patients with PROC, correlating highly with poor prognoses for patients.

CONCLUSIONS

HIF1α stabilization is regulated by TGFβ1/ERK/PHD2 axis in PROC. Hence, inhibiting TGFβ1, ERK, or HIF1α is potential strategy for treating patients with PROC.

Oncogenic microRNA signature for early diagnosis of cervical intraepithelial neoplasia and cancer

Cervical cancer is one of the leading causes of cancer death in women globally, despite the widespread use of cytology/human papillomavirus (HPV) screening. In the present study, we aimed to identify the potential role of microRNA (miRNA) as a diagnostic biomarker in the detection of cervical pre‐malignant lesions and cancer. In total, we recruited 582 patients with cervical diseases and 145 control individuals. The expression levels of six miRNAs (miR‐20a, miR‐92a, miR‐141, miR‐183*, miR‐210 and miR‐944) were found to be significantly up‐regulated in cervical cancer and pre‐malignant lesions compared to normal cervical samples, indicating that they are oncogenic miRNAs. Receiver operating characteristic curve analysis showed that these six miRNAs can be used to distinguish patients with cervical pre‐malignant lesions or cancer from normal individuals and they also had a good predictive performance, particularly in cervical lesions. Combined use of these six miRNAs further enhanced the diagnostic accuracy over any single miRNA marker, with an area under the curve of 0.998, 0.996 and 0.959, a diagnostic sensitivity of 97.9%, 97.2% and 91.4%, and a specificity of 98.6%, 96.6% and 87.6% for low‐grade lesions, high‐grade lesions and cancer, respectively. This six oncogenic miRNA signature may be suitable for use as diagnostic marker for cervical pre‐malignant lesions and cancer in the near future.

Amyloid Precursor Protein Overexpression in Down Syndrome Trophoblast Reduces Cell Invasiveness and Interferes with Syncytialization

The placentas of Down syndrome (DS) pregnancies exhibit morphologic and functional abnormalities. Although the increase in dosage of certain genes on chromosome 21 has been associated with the DS phenotype, the effects on placenta have seldom been studied. Herein, we examine the expression of four dosage-sensitive genes (APP, ETS2, SOD1, and HMGN1) in normal and DS placentas. We demonstrated significant overexpression of amyloid precursor protein (APP) in DS placentas at RNA and protein levels by real-time quantitative PCR, Western blot analysis, and immunohistochemistry. Inducible APP overexpression trophoblast cell line models were established using a Tet-On system. APP induction in HTR-8/SVneo dose-dependently decelerated cell growth, enhanced apoptosis, and reduced cell migration and invasion when compared with the uninduced controls. Concomitantly, decreased β-human chorionic gonadotropin in the culture medium was also detected on induction. Moreover, although forskolin treatment induced α/β-human chorionic gonadotropin and syncytin expression in BeWo cells, such induction of syncytialization was inhibited by APP overexpression. E-cadherin immunofluorescence also demonstrated a decrease in syncytia formation in forskolin-treated BeWo-overexpressing APP. By liquid chromatography-tandem mass spectrometry, proteins related to cell-cell adhesion, protein translation, processing, and folding were found to be up-regulated in APP-induced HTR-8/SVneo clones. Our data demonstrated, for the first time, the effects of increased APP expression in DS placenta.

DUOXA1-mediated ROS production promotes cisplatin resistance by activating ATR-Chk1 pathway in ovarian cancer

The acquisition of resistance is a major obstacle to the clinical use of platinum drugs for ovarian cancer treatment. Increase of DNA damage response is one of major mechanisms contributing to platinum-resistance. However, how DNA damage response is regulated in platinum-resistant ovarian cancer cells remains unclear. Using quantitative high throughput combinational screen (qHTCS) and RNA-sequencing (RNA-seq), we show that dual oxidase maturation factor 1 (DUOXA1) is overexpressed in platinum-resistant ovarian cancer cells, resulting in over production of reactive oxygen species (ROS). Elevated ROS level sustains the activation of ATR-Chk1 pathway, leading to resistance to cisplatin in ovarian cancer cells. Moreover, using qHTCS we identified two Chk1 inhibitors (PF-477736 and AZD7762) that re-sensitize resistant cells to cisplatin. Blocking this novel pathway by inhibiting ROS, DUOXA1, ATR or Chk1 effectively overcomes cisplatin resistance in vitro and in vivo. Significantly, the clinical studies also confirm the activation of ATR and DOUXA1 in ovarian cancer patients, and elevated DOUXA1 or ATR-Chk1 pathway correlates with poor prognosis. Taken together, our findings not only reveal a novel mechanism regulating cisplatin resistance, but also provide multiple combinational strategies to overcome platinum-resistance in ovarian cancer.

Autocrine activation of JAK2 by IL-11 promotes platinum drug resistance

Antineoplastic platinum agents are used in first-line treatment of ovarian cancer, but treatment failure frequently results from platinum drug resistance. Emerging observations suggest a role of reactive oxygen species (ROS) in the resistance of cancer drugs including platinum drugs. However, the molecular link between ROS and cellular survival pathway is poorly understood. Using quantitative high-throughput combinational screen (qHTCS) and genomic sequencing, we show that in platinum-resistant ovarian cancer elevated ROS levels sustain high level of IL-11 by stimulating FRA1-mediated IL-11 expression and increased IL-11 causes resistance to platinum drugs by constitutively activating JAK2-STAT5 via an autocrine mechanism. Inhibition of JAK2 by LY2784544 or IL-11 by anti-IL-11 antibody overcomes the platinum resistance in vitro or in vivo. Significantly, clinic studies also confirm the activated IL-11-JAK2 pathway in platinum-resistant ovarian cancer patients, which highly correlates with poor prognosis. These findings not only identify a novel ROS-IL-11-JAK2-mediated platinum resistance mechanism but also provide a new strategy for using LY2784544- or IL-11-mediated immunotherapy to treat platinum-resistant ovarian cancer.

Differential expression of estrogen receptor subtypes and variants in ovarian cancer: effects on cell invasion, proliferation and prognosis

BACKGROUND

Due to the presence of both classical estrogen receptor (ERα) and another ER subtype (ERβ) in ovarian cancer, hormonal treatment is an attractive option. However, response to tamoxifen in ovarian cancer is modest. The presence of ERβ variants further complicated the issue. We have recently shown that specifically targeting ER subtypes using selective ER modulators showed opposing functions of ER subtypes on cell growth. In the present study, the clinical significance of ERα and ERβ variants (β1, β2 and β5) and the functional effects of ERβ2 and ERβ5 in ovarian cancer was investigated.

METHODS

ERα, ERβ1, ERβ2 and ERβ5 expression were evaluated by immunohistochemistry in 106 ovarian cancer tissues. The association between ERs expression and clinicopathological parameters or prognosis was analyzed. Ectopic expression of ERβ2 and ERβ5 followed by functional assays were performed in ovarian cancer cell lines in order to detect their effects on cell invasion and proliferation.

RESULTS

We found significantly higher nuclear (n)ERα and nERβ5 and lower cytoplasmic (c)ERα expression in advanced cancers. Significantly lower ERβ1 expression was also detected in high grade cancers. Significant loss of nERα and cERβ2 expression were observed in clear cell histological subtypes. Higher nERβ5 and lower cERβ5 expression were associated with serous/clear cell subtypes, poor disease-free and overall survival. Positive cERα and higher cERβ1 expression were significantly associated with better disease-free and overall survival. Furthermore, we found nERβ5 as an independent prognostic factor for overall survival. Functionally, overexpression of ERβ5 enhanced ovarian cancer cell migration, invasion and proliferation via FAK/c-Src activation whereas ERβ2 induced cell migration and invasion.

CONCLUSIONS

Since tamoxifen binds to both ERα and ERβ1 which appear to bear opposing oncogenic roles, the histotypes-specific expression pattern of ERs indicates that personalized treatment for women based on ERs expression using selective estrogen receptor modulators may improve response rate. This study also suggests nERβ5 as a potential prognostic marker and therapeutic target in ovarian cancer.

The mitosis-specific marker phosphohistone-H3 (PHH3) is an independent prognosticator in uterine smooth muscle tumours: an outcome-based study

AIMS

Accurate mitosis counting, which is important in the diagnosis of uterine smooth muscle tumours (USMTs), is often difficult and subjective. The mitosis-specific immunohistochemical marker phosphohistone-H3 (PHH3) has been shown to be diagnostically useful, but its expression, in relation to outcome, has not been thoroughly investigated. The aim of this study is to evaluate PHH3 as a diagnostic and prognostic marker in USMTs.

METHODS AND RESULTS

PHH3 expression was evaluated in 55 leiomyosarcomas (LMSs), 26 smooth muscle tumours of uncertain malignant potential (STUMPs), 18 leiomyomas with bizarre nuclei (LBN), and 12 leiomyomas (LMs). Scores were expressed as counts per 10 high-power fields (HPFs). Median follow-up durations of patients with LMS, STUMP, LBN and LM were, respectively, 39, 78, 65.5 and 49.5 months. Twenty-eight patients with LMSs (50.9%) died, and two (7.7%) patients with STUMPs experienced recurrence. The median PHH3 scores for LMSs were significantly higher than those for other categories of tumour. A score of ≥29/10 HPFs was also independently associated with a poor outcome. To test whether the PHH3 score could distinguish between benign USMTs with atypical histology and those that were clinically malignant, two biological groups were further delineated. Patients in group 1 (18 LBNs and 24 STUMPs) all had an uneventful outcome, whereas patients in group 2 (two recurrent STUMPs and 32 LMSs) all had a recurrence or tumour-related death. Median PHH3 scores for the two groups were, respectively, 2/10 HPFs and 27/10 HPFs. A PHH3 score of ≥7/10 HPFs was highly associated with malignancy.

CONCLUSION

PHH3 is useful in evaluation of the biological behaviour of USMTs, and may serve as a prognostic indicator for LMSs.

FBI-1 Is Overexpressed in Gestational Trophoblastic Disease and Promotes Tumor Growth and Cell Aggressiveness of Choriocarcinoma via PI3K/Akt Signaling

Human placental trophoblasts can be considered pseudomalignant, with tightly controlled proliferation, apoptosis, and invasiveness. Gestational trophoblastic disease (GTD) represents a family of heterogeneous trophoblastic lesions with aberrant apoptotic and proliferative activities and dysregulation of cell signaling pathways. We characterize the oncogenic effects of factor that binds to the inducer of short transcripts of HIV-1 [FBI-1, alias POZ and Krüppel erythroid myeloid ontogenic factor (POKEMON)/ZBTB7A] in GTD and its role in promoting cell aggressiveness in vitro and tumor growth in vivo. IHC studies showed increased nuclear expression of FBI-1, including hydatidiform moles, choriocarcinoma (CCA), and placental site trophoblastic tumor, in GTD. In JAR and JEG-3 CCA cells, ectopic FBI-1 expression opposed apoptosis through repression of proapoptotic genes (eg, BAK1, FAS, and CASP8). FBI-1 overexpression also promoted Akt activation, as indicated by Akt-pS473 phosphorylation. FBI-1 overexpression promoted mobility and invasiveness of JEG-3 and JAR, but not in the presence of the phosphoinositide 3-kinase inhibitor LY294002. These findings suggest that FBI-1 could promote cell migration and invasion via phosphoinositide 3-kinase/Akt signaling. In vivo, nude mice injected with CCA cells with stable FBI-1 knockdown demonstrated reduced tumor growth compared with that in control groups. These findings suggest that FBI-1 is clinically associated with the progression of, and may be a therapeutic target in, GTD, owing to its diverse oncogenic effects on dysregulated trophoblasts.

Stem cell transcription factor NANOG in cancers--is eternal youth a curse?

INTRODUCTION

Targeting cancer stem cells can be a more effective approach to treat cancer. NANOG is one of the key factors for maintaining the self-renewal ability and pluripotency of stem cells, including cancer stem cells. Overexpression of NANOG has been observed in various human malignancies. Several reports have suggested that NANOG contributes to carcinogenesis by initiating and preserving cancer stem cells. It is obvious that NANOG is also involved in establishing other hallmarks of cancer such as uncontrolled cell growth, chemoresistance, metastasis, and immune evasion.

AREAS COVERED

This review will discuss the molecular properties and oncogenic roles of NANOG. The idea of using agents that inhibit the transcription factor to treat cancer is presented. Interfering with NANOG-mediated transcriptions using small interfering RNA, transcription factor decoy, genome editing, and small-molecule inhibitors may provide novel strategies to target cancer stem cells.

EXPERT OPINION

As a pivotal controller in cancer stem cell maintenance and a positive regulator of various oncogenic pathways, NANOG may be an important target for cancer therapy. However, as a transcription factor, it is inherently difficult to target by pharmacological means. Novel approaches need to be explored before the inhibition of NANOG can be applied in a clinical setting.

p21-Activated Kinases 1, 2 and 4 in Endometrial Cancers: Effects on Clinical Outcomes and Cell Proliferation

p21-activated kinases (Paks) are serine/threonine protein kinases involved in biological events linked to malignant tumor progression. In this study, expression of Pak1, p-Pak2 Ser²⁰, Pak4, pPak4 Ser⁴⁷⁴ in 21 normal endometrium, 16 hyperplastic endometrium without atypia, 17 atypical complex hyperplasia and 67 endometrial cancers was assessed by immunohistochemistry and correlated with clinicopathological parameters. We also accessed the proliferative role and downstream targets of Pak1 in endometrial cancer. Pak1 was expressed in cytoplasm whereas Pak4 and p-Pak4 were expressed in both cytoplasm and nucleus of endometrial tissues. In normal endometrium, significantly higher Pak1 (P = 0.028) and cytoplasmic p-Pak2 (P = 0.048) expression was detected in proliferative endometrium than secretory endometrium. Pak1, cytoplasmic and nuclear Pak4 and nuclear p-Pak4 was significantly overexpressed in endometrial cancer when compared to atrophic endometrium (all P<0.05). Moreover, type I endometrioid carcinomas showed significantly higher Pak1 expression than type II non-endometrioid carcinomas (P<0.001). On the other hand, Pak1, Pak4 and p-Pak4 expression negatively correlated with histological grade (all P<0.05) while p-Pak2 and cytoplasmic Pak4 expression inversely correlated with myometrial invasion (all P<0.05). Furthermore, patients with endometrial cancers with lower cytoplasmic Pak4 expression showed poorer survival (P = 0.026). Multivariate analysis showed cytoplasmic Pak4 is an independent prognostic factor. Functionally, knockdown of Pak1, but not Pak4, in endometrial cancer cell line led to reduced cell proliferation along with reduced cyclin D1, estrogen receptor (ERα) and progestogen receptor (PR) expression. Significant correlation between Pak1 and PR expression was also detected in clinical samples. Our findings suggest that Pak1 and cytoplasmic p-Pak2 may promote cell proliferation in normal endometrium during menstral cycle. Pak1, cytoplasmic and nuclear Pak4 and nuclear p-Pak4 are involved in the pathogenesis of endometrial cancer especially in postmenopausal women. Pak1 promote endometrial cancer cell proliferation, particular in type I endometrioid carcinoma. Cytoplasmic Pak4 can be potential prognostic marker in endometrial cancer.

HPV 16 E2 binding sites 1 and 2 become more methylated than E2 binding site 4 during cervical carcinogenesis

E2 protein binding to the four E2 binding sites (E2BSs) at the long control region of Human Papillomavirus (HPV) 16/18 genome may exert either transcriptional activation/repression on E6 and E7 oncoproteins. Methylation status at the E2BSs may affect the relative binding of E2 protein to them. In this study, methylation percentage at E2BS 1, 2 (promoter-proximal), and 4 (promoter-distal) were assessed by pyrosequencing and compared among HPV 16/18-positive cervical cancer, high-grade, and low-grade Cervical Intraepithelial Neoplasia, Atypical Squamous Cells of Undetermined Significance, and normal cervical epithelium. HPV 16 E2BS1&2 were more methylated than HPV 16 E2BS4 in cervical cancer whereas in cervical premalignant lesions and normal epithelium, HPV 16 E2BS1&2 were less methylated than HPV 16 E2BS4. HPV 18 E2BS1&2 remained more methylated than E2BS4 in all histological groups. HPV 16 E2BS1&2 methylation increased from high-grade lesions to cervical cancer (P < 0.001). HPV 16 E2BS4 methylation increased from low-grade to high-grade premalignant lesions (P = 0.041). Both HPV 18 E2BS1&2 and E2BS4 methylation increased from low-grade to high-grade Cervical Intraepithelial Neoplasia (P = 0.019 and 0.001 respectively) and further increased form high-grade lesions to cervical cancer (P < 0.001 and 0.005 respectively). Conclusively, HPV 16 E2BS1&2 (for transcriptional repression of E6/E7 oncoproteins) became more heavily methylated than E2BS4 (for transcriptional activation of E6/E7) in cervical cancer, favouring the differential binding of E2 protein to E2BS4. Increasing methylation at HPV 16/18 E2BSs are potentially useful adjunctive molecular markers for predicting progression from low-grade to high-grade cervical premalignant lesions and from high-grade lesions to cervical cancer.

Overexpression of forkhead box protein M1 (FOXM1) in ovarian cancer correlates with poor patient survival and contributes to paclitaxel resistance

Aim

Deregulation of FOXM1 has been documented in various cancers. The aim of this study was to evaluate the role of FOXM1 in ovarian cancer tumorigenesis and paclitaxel resistance.

Experimental Design

Expression of FOXM1 was examined in 119 clinical samples by immunohistochemistry and correlated with clinicopathological parameters. Effects of FOXM1 knockdown on ovarian cancer cell migration, invasion and mitotic catastrophe were also studied. qPCR and ChIP-qPCR were used to establish KIF2C as a novel FOXM1 target gene implicated in chemoresistance.

Results

High nuclear FOXM1 expression in ovarian cancer patient samples was significantly associated with advanced stages (P = 0.035), shorter overall (P = 0.019) and disease-free (P = 0.014) survival. Multivariate analysis confirmed FOXM1 expression as an independent prognostic factor for ovarian cancer. FOXM1 knockdown significantly inhibited migration and invasion of ovarian cancer cells and enhanced paclitaxel-mediated cell death and mitotic catastrophe in a p53-independent manner. Bioinformatics analysis suggested a number of potential transcription targets of FOXM1. One of the potential targets, KIF2C, exhibited similar expression pattern to FOXM1 in chemosensitive and chemoresistant cells in response to paclitaxel treatment. FOXM1 could be detected at the promoter of KIF2C and FOXM1 silencing significantly down-regulated KIF2C.

Conclusion

Our findings suggest that FOXM1 is associated with poor patient outcome and contributes to paclitaxel resistance by blocking mitotic catastrophe. KIF2C is identified as a novel FOXM1 transcriptional target that may be implicated in the acquisition of chemoresistance. FOXM1 should be further investigated as a potential prognostic marker and therapeutic target for ovarian cancer.

Downregulation of the gli transcription factors regulator Kif7 facilitates cell survival and migration of choriocarcinoma cells

The kinesin protein Kif7 has been recognized as an integral component of hedgehog signalling. Aberrant activation of hedgehog signalling has been implicated in many human solid tumours. Gestational trophoblastic disease includes frankly malignant choriocarcinoma and potentially malignant hydatidiform mole. Here we investigated the hedgehog signalling components expression profiles in gestational trophoblastic disease. Downregulation of Gli1, Gli2, Gli3 and Kif7 was demonstrated in clinical samples of choriocarcinoma and hydatidiform moles as well as choriocarcinoma cell lines when compared with normal placentas. Ectopic expression of Kif7 in two choriocarcinoma cell lines JAR and JEG-3 led to a decrease in cell growth and increase in apoptosis demonstrated by MTT and TUNEL assays, respectively. Overexpression of Kif7 also led to suppressed cell migration through transwell assay. In contrast, knocking down Kif7 in HTR-8/SVneo, an immortalized trophoblast cell line, increased cell number over time and increased the migratory ability of the cells. Taken together, Kif7 may contribute to pathogenesis of gestational trophoblastic disease through enhancing survival and promoting dissemination of trophoblasts.

miR-135a leads to cervical cancer cell transformation through regulation of β-catenin via a SIAH1-dependent ubiquitin proteosomal pathway

Human papillomaviruses (HPVs) is the principal etiological agent of cervical cancer (CC). However, exposure to the high-risk type HPV alone is insufficient for tumor formation, and additional factors are required for the HPV-infected cells to become tumorigenic. Dysregulated microRNAs (miRNAs) expression is frequently observed in cancer but their roles in the formation of CC have not been fully revealed. In this study, we compared the expression of miR-135a in laser capture microdissected cervical specimens and confirmed overexpression of the miRNA in malignant cervical squamous cell carcinoma compared with precancerous lesions. Transient force-expression of miR-135a induced growth in low-density culture, anchorage-independent growth, proliferation and invasion of a HPV-16 E6/E7-immortalized cervical epithelial cell line, NC104-E6/E7. The observed effects were due to the inhibitory action of miR-135a on its direct target seven in absentia homolog 1 (SIAH1) leading to upregulation of β-catenin/T cell factor signaling. miR-135a force-expression enhanced the growth of HeLa- and NC104-E6/E7-derived tumor in vivo. The effect of miR-135a could be partially nullified by SIAH1 force-expression. More importantly, the expression of SIAH1 and β-catenin correlated with that of miR-135a in precancerous and cancerous lesions of cervical biopsies. By comparing the tumorigenic activities of miR-135a in E6/E7 positive/negative cell lines and in NC104-E6/E7 with or without E6/E7 knockdown, we demonstrated that HPV E6/E7 proteins are prerequisite for miR-135a as an oncomiR. Taken together, miR-135a/SIAH1/β-catenin signaling is important in the transformation and progression of cervical carcinoma.

BRCA1 deficiency induces protective autophagy to mitigate stress and provides a mechanism for BRCA1 haploinsufficiency in tumorigenesis

Stress adaptation has profound impacts on malignant progression and response to treatment. BRCA1 is an important modulator of cellular stress, but our understanding of its mechanisms of action remains incomplete. Here we identify autophagy as an essential mechanism protecting BRCA1 deficient cancer cells from metabolic stress and allow their survival, which may underlie its significant cancer-promoting properties. We showed that targeted inhibition of endogenous BRCA1 using small interfering RNA caused significant autophagy in response to serum starvation and endoplasmic reticulum stress, whereas overexpression of BRCA1 did not, confirming that the effect was BRCA1 specific. We demonstrated that Beclin 1 was activated in BRCA1 deficient cells, suggesting involvement of a canonical pathway. Importantly, BRCA1 deficient cells were highly dependent on autophagy for survival, and rapidly underwent cell death upon disruption of autophagy. Notably, this dependence on protective autophagy extended to their tissue of origin, as ovarian surface epithelial cells from women testing positive for BRCA1 mutations, in contrast to those with no mutations, robustly induced autophagy to mitigate the stress and promote their survival. These findings highlight a novel role for BRCA1 in protective autophagy, which may make its essential contribution to tumorigenesis and prognosis.

Downregulation of ASPP2 in choriocarcinoma contributes to increased migratory potential through Src signaling pathway activation

Gestational choriocarcinoma is a malignant tumor derived from placental trophoblast and the most aggressive member of gestational trophoblastic disease (GTD). Apoptosis-stimulating protein of p53-2 (ASPP2) is a member of ASPP family that transactivates p53 and thereby functions as a tumor suppressor. In this study, the expression profile of ASPP2 in choriocarcinoma was examined in comparison with normal placentas and hydatidiform moles, the latter being a type of GTD that carries malignant potential. Downregulation of ASPP2 messenger RNA and protein was demonstrated in choriocarcinoma by quantitative PCR and immunohistochemistry. ASPP2-transfected choriocarcinoma cells (JEG-3 and JAR) showed an increase in apoptosis and a decrease in cell migration as detected by TdT-mediated dUTP nick end labeling and wound healing assays, respectively, illustrating the complex action of ASPP2 on cell functions other than programmed cell death. Activated Src is known to be important in tumor progression. Transfection of ASPP2 but not ASPP1, another tumor-suppressive ASPP, was found to be related to subsequent decreased Src-pY416 phosphorylation, suggesting an inactivating effect of ASPP2 on Src. Moreover, this ASPP2-mediated inactivation of Src could be abolished by RNA interference with C-terminal Src kinase (Csk), a kinase that can inhibit Src activation. Our findings suggested that the ability of ASPP2 to attenuate Src activation was specific to ASPP2 in a Csk-dependent manner. Taken together, we demonstrated a loss of tumor-suppressive ASPP2 in choriocarcinoma with effects on cell migration and apoptosis. We also unveiled a possible mechanistic link between ASPP2 and Csk/Src signaling pathway, implicating the multiple cellular functions of ASPP2.

AMPK activators suppress cervical cancer cell growth through inhibition of DVL3 mediated Wnt/β-catenin signaling activity

Recent evidence has suggested that AMPK activators may be applied as therapeutic drugs in suppressing cancer cell growth. However, the molecular mechanism of their suppressive function in cancer cells is still unclear. Here we show that AMPK activators impair cervical cancer cell growth through the reduction of DVL3, a positive regulator in Wnt/β-catenin signaling and an oncogenic player in cervical cancer tumorigenesis. By western blot and immunohistochemical analyses, we demonstrated that DVL3 was frequently upregulated and significantly associated with elevated β-catenin (P = 0.009) and CyclinD1 (P = 0.009) expressions in cervical cancer. Enforced expression of DVL3 elevated β-catenin and augmented cervical cancer cell growth, verifying that DVL3-mediated Wnt/β-catenin activation is involved in cervical cancer oncogenesis. On the other aspect, we noted that the cervical cancer cell growth was remarkably suppressed by AMPK activators and such cell growth inhibition was in concomitant with the reduction of DVL3 protein level in dose- and time-dependent manners. Besides, impaired mTOR signaling activity also reduced DVL3 expression. In contrast, co-treatment with Compound C (AMPK inhibitor) could significantly abrogate metformin induced DVL3 reduction. In addition, co-treatment with AM114 or MG132 (proteosomal inhibitors) could partially restore DVL3 expression under the treatment of metformin. Further in vivo ubiquitination assay revealed that metformin could reduce DVL3 by ubiquitin/proteasomal degradation. To our knowledge, this is the first report showing the probable molecular mechanisms of that the AMPK activators suppress cervical cancer cell growth by impairing DVL3 protein synthesis via AMPK/mTOR signaling and/or partially promoting the proteasomal degradation of DVL3.

Dysregulated stemness-related genes in gynecological malignancies

In recent years, much attention has been paid to the concept of cancer stem cells (CSC) and self-renewal related pathways in cancer biology. This review outlines the dysregulated stemness-related genes or transcription factors in gynecological cancers. Hedgehog (Hh) and Notch signaling are important pathways in tissue pattern programming and cell fate determination during embryonic development. Hyperactivation of these two pathways was frequently observed in gynecological malignancies such as ovarian, endometrial and cervical cancers. In contrast, the expression profiles of pluripotency-regulating core transcriptional circuitry: Nanog, Oct4 and Sox2 appear heterogeneous. Among these transcription factors, overexpression of Nanog was found to exert a prominent effect in gynecological tumorigenesis, while dysregulations of Oct4 and Sox2 may vary in a context dependent manner. On the other hand, the isolation of putative CSC illustrates a hierarchy model of tumor heterogeneity, in which only a subset of cells among biologically distinct populations can initiate tumor growth. Re-activation of these pluripotent transcription factors (Nanog, Oct4 and/or Sox2) in association with distinct tumorigenic properties could be found in clones isolated from gynecological tumors using various approaches. Recent understanding on the roles of Hh and Notch signaling in enhancing CSC survival may help to better understand the mechanism of carcinogenesis and identify new pharmaceutical targets for gynecological malignancies.

Paradoxical impact of two folate receptors, FRα and RFC, in ovarian cancer: effect on cell proliferation, invasion and clinical outcome

Despite being an essential vitamin, folate has been implicated to enhance tumor growth, as evidenced by reports on overexpression of folate receptor alpha (FRα) in carcinomas. The role of another folate transporter, reduced folate carrier (RFC), is largely unknown. This study investigated the roles of folate, FRα and RFC in ovarian cancers. We demonstrated FRα mRNA and protein overexpression and reduced RFC expression in association with FRα gene amplification and RFC promoter hypermethylation, respectively. FRα overexpression was associated with tumor progression while RFC expression incurred a favorable clinical outcome. Such reciprocal expression pattern was also observed in ovarian cancer cell lines. Folate was shown to promote cancer cell proliferation, migration and invasion in vitro, and down-regulate E-cadherin expression. This effect was blocked after either stable knockdown of FRα or ectopic overexpression of RFC. This hitherto unreported phenomenon suggests that, RFC can serve as a balancing partner of FRα and confer a protective effect in patients with high FRα-expressing ovarian carcinomas, as evidenced by their prolonged overall and disease-free survivals. In conclusion, we report on the paradoxical impact of FRα (putative oncogenic) and RFC (putative tumor suppressive) in human malignancies. FRα and RFC may potentially be explored as therapeutic target or prognostic marker respectively. We recommend caution and additional research on folate supplements in cancer patients.

Possible role of adrenomedullin in the pathogenesis of tubal ectopic pregnancy

CONTEXT

Tubal ectopic pregnancy (tEP) is currently the leading cause of pregnancy-related deaths during the first trimester. Our current knowledge on the molecular pathogenesis is limited.

OBJECTIVE

The objective of the study was to find out the possible role of adrenomedullin (ADM) in the pathogenesis of tEP.

DESIGN

This was an experimental in vitro study on oviductal tissue.

SETTING

The study was conducted at a university teaching hospital.

PATIENTS AND INTERVENTIONS

Patients included those having oviducts removed surgically during salpingectomy for tEP or hysterectomy for benign gynecological conditions. Oviductal tissues were incubated in hormonal condition mimicking early pregnancy before used for in vitro experiments.

MAIN OUTCOME MEASURES

Plasma ADM concentration, oviductal expression of ADM and its receptors, ciliary beat frequency, smooth muscle contraction were measured.

RESULTS

The ciliary beat frequency and frequency of muscle contraction were lower in the oviducts from patients with tEP than those from simulated normal pregnancy. The plasma and oviductal tissue ADM levels were also lower. The decreases in ciliary beat and frequency of contraction were restored to normal after ADM treatment.

CONCLUSIONS

The results suggest that the lower ADM level in the oviducts of tEP may lead to the decrease in ciliary beating and muscle contraction, with the result that the embryo is retained and implanted in the oviduct. Our findings explain for the first time the etiology of tubal pregnancy on the basis of an impairment of the transport of the fertilized ovum resulting from an ADM deficiency and raise the possibility of using the plasma ADM level as a predictor for tubal ectopic pregnancy.

Increased expression of PITX2 transcription factor contributes to ovarian cancer progression

BACKGROUND

Paired-like homeodomain 2 (PITX2) is a bicoid homeodomain transcription factor which plays an essential role in maintaining embryonic left-right asymmetry during vertebrate embryogenesis. However, emerging evidence suggests that the aberrant upregulation of PITX2 may be associated with tumor progression, yet the functional role that PITX2 plays in tumorigenesis remains unknown.

PRINCIPAL FINDINGS

Using real-time quantitative RT-PCR (Q-PCR), Western blot and immunohistochemical (IHC) analyses, we demonstrated that PITX2 was frequently overexpressed in ovarian cancer samples and cell lines. Clinicopathological correlation showed that the upregulated PITX2 was significantly associated with high-grade (P = 0.023) and clear cell subtype (P = 0.011) using Q-PCR and high-grade (P<0.001) ovarian cancer by IHC analysis. Functionally, enforced expression of PITX2 could promote ovarian cancer cell proliferation, anchorage-independent growth ability, migration/invasion and tumor growth in xenograft model mice. Moreover, enforced expression of PITX2 elevated the cell cycle regulatory proteins such as Cyclin-D1 and C-myc. Conversely, RNAi mediated knockdown of PITX2 in PITX2-high expressing ovarian cancer cells had the opposite effect.

CONCLUSION

Our findings suggest that the increased expression PITX2 is involved in ovarian cancer progression through promoting cell growth and cell migration/invasion. Thus, targeting PITX2 may serve as a potential therapeutic modality in the management of high-grade ovarian tumor.

iASPP and chemoresistance in ovarian cancers: effects on paclitaxel-mediated mitotic catastrophe

PURPOSE

iASPP is a specific regulator of p53-mediated apoptosis. Herein, we provided the first report on the expression profile of iASPP in ovarian epithelial tumor and its effect on paclitaxel chemosensitivity.

EXPERIMENTAL DESIGN

Expression and amplification status of iASPP was examined in 203 clinical samples and 17 cell lines using immunohistochemistry, quantitative real-time PCR, and immunoblotting, and correlated with clinicopathologic parameters. Changes in proliferation, mitotic catastrophe, apoptosis, and underlying mechanism in ovarian cancer cells of different p53 status following paclitaxel exposure were also analyzed.

RESULTS

The protein and mRNA expression of iASPP was found to be significantly increased in ovarian cancer samples and cell lines. High iASPP expression was significantly associated with clear cell carcinoma subtype (P = 0.003), carboplatin and paclitaxel chemoresistance (P = 0.04), shorter overall (P = 0.003), and disease-free (P = 0.001) survival. Multivariate analysis confirmed iASPP expression as an independent prognostic factor. Increased iASPP mRNA expression was significantly correlated with gene amplification (P = 0.023). iASPP overexpression in ovarian cancer cells conferred resistance to paclitaxel by reducing mitotic catastrophe in a p53-independent manner via activation of separase, whereas knockdown of iASPP enhanced paclitaxel-mediated mitotic catastrophe through inactivating separase. Both securin and cyclin B1/CDK1 complex were involved in regulating separase by iASPP. Conversely, overexpressed iASPP inhibited apoptosis in a p53-dependent mode.

CONCLUSIONS

Our data show an association of iASPP overexpression with gene amplification in ovarian cancer and suggest a role of iASPP in poor patient outcome and chemoresistance, through blocking mitotic catastrophe. iASPP should be explored further as a potential prognostic marker and target for chemotherapy.

Zic2 synergistically enhances Hedgehog signalling through nuclear retention of Gli1 in cervical cancer cells

Aberrant activation of Hedgehog (Hh) signalling has been implicated in the pathogenesis of human cancers. However, the cognate molecular mechanisms contributing to this disregulated pathway are incompletely understood. In this study, we showed that Zic2 was frequently over-expressed and associated with high-grade cervical cancer (p = 0.032), high levels of Gli1 (p < 0.001) and CyclinD1 (p < 0.001) by immunohistochemical and quantitative RT-PCR analyses. Further biochemical studies using luciferase reporter, co-immunoprecipitation, subcellular fractionation and immunofluorescence analyses demonstrated that Zic2 can physically interact with Gli1 and retain it in the nucleus, which in turn increases Gli-mediated transcriptional activity. Gain- and loss-of-function analyses of Zic2 showed that Zic2 could increase Hh signalling activity, cell proliferation and anchorage-independent growth ability in cervical cancer cells. Conversely, deletion of the zinc finger domain at C-terminus of Zic2 significantly abrogated its interaction with Gli1, the retention of Gli1 in the nucleus, effects on Hh signalling activity and oncogenic properties in cervical cancer cells. Our findings suggest that Zic2 is a positive modulator increasing Gli1 transcriptional and oncogenic activity by retaining Gli1 in the nucleus of cervical cancer cells.

Overexpressed PAK4 promotes proliferation, migration and invasion of choriocarcinoma

Gestational trophoblastic disease (GTD) includes frankly malignant choriocarcinoma (CCA) and placental site trophoblastic tumor and potentially malignant hydatidiform mole. p21-Activated kinase (PAK) 4 promotes cell motility. This study investigated the role of PAK4 in the pathogenesis of GTD. PAK4 messenger RNA and protein expressions in clinical samples and cell lines of normal placentas and GTD were determined by quantitative real-time polymerase chain reaction and western blot, respectively. The effects of human chorionic gonadotropin (hCG) and phosphoinositide 3 kinase (PI3K) on the expression and activation of PAK4 were investigated by treating CCA JEG3 and JAR cells with anti-hCG antibody and PI3K inhibitor, respectively. The effects of PAK4 on CCA cell proliferation, migration and invasion were assessed by corresponding functional assays. We demonstrated overexpression of PAK4 in GTD and CCA cell lines at both RNA and protein level. hCG is one of the upstream regulators of PAK4 expression, whereas activation of PAK4 is PI3K/PKB dependent in JEG3 and JAR cells. Significant correlation was found between PAK4 expression and proliferation index minichromosome maintenance complex component 7 (P = 0.007). In JEG3 and JAR cells, stably transfected PAK4 increased proliferation, migration and invasion, whereas small interfering RNA knockdown of PAK4 decreased proliferation, migration and invasion along with downregulated CDK6 and membrane-type 1 matrix metalloproteinase (MT1-MMP) and upregulated p16. We further found PAK4-mediated transcription of MT1-MMP in CCA cells by luciferase reporter assay. Our results demonstrated for the first time that overexpressed PAK4 was involved in the pathogenesis of GTD, promoting proliferation and enhancing cell migration and invasion in CCA cells.

P-cadherin cooperates with insulin-like growth factor-1 receptor to promote metastatic signaling of gonadotropin-releasing hormone in ovarian cancer via p120 catenin

Gonadotropin-releasing hormone (GnRH) is a potent prometastatic factor in ovarian cancer, but the intracellular signaling events are not well understood. The classical Gα(q)-phospholipase C signal transduction pathway known to operate in the pituitary is not involved in GnRH actions at non-pituitary targets. Here we showed that GnRH treatment of ovarian cancer cells led to a rapid and remarkable tyrosine phosphorylation of p120 catenin (p120(ctn)), which was mediated by P-cadherin. The use of P-cadherin small interfering RNA or neutralizing antibodies to inhibit P-cadherin expression and function resulted in diminished p120(ctn) activation, confirming that the effect was P-cadherin specific. On exploring how P-cadherin, which lacks intrinsic kinase activity, might regulate the activation of p120(ctn), we found that P-cadherin could induce the ligand-independent activation of insulin-like growth factor-1 receptor (IGF-1R). Inhibition of IGF-1R expression or its activity significantly inhibited GnRH-induced p120(ctn) activation, and the subsequent cell migration and invasion. In addition, we showed that IGF-1R regulation by P-cadherin was associated with complex formation between IGF-1R and P-cadherin, and this regulation was also observed to be in vivo correlated with metastasis. Furthermore, using a mouse model of ovarian cancer metastasis, GnRH receptor knockdown was shown to diminish peritoneal dissemination of tumors and ascites formation. These findings suggest for the first time that GnRH can initiate an outside-in p120(ctn) signal transduction through the cross-talk between P-cadherin and IGF-1R, thus providing a novel molecular mechanism by which GnRH may control the high level of aggressiveness and invasion and metastasis potential that are characteristic of ovarian cancer.

Atypical glandular cells diagnosed during pregnancy and the postpartum period: a retrospective analysis

OBJECTIVES

The objective of the study was to determine the prevalence and clinical significance of atypical glandular cells (AGC) or atypical glandular cells of undetermined significance (AGUS) diagnosed in pregnant and postpartum women.

STUDY DESIGN

Smears having a diagnosis of AGC or AGUS, taken from pregnant and postpartum (within six weeks after delivery) women between 1995 and 2008 were reviewed and subclassified according to the Bethesda 2001 classification. Case records were then reviewed and a second cytology review was performed after disclosure of the follow-up data.

RESULTS

Among 91,133 smears taken from pregnant and postpartum women, 70 had AGC or AGUS (0.07%) diagnosed. Follow-up data were available in 40 cases, with mean duration of follow-up being 43 months. Among the 40 patients with follow-up data, nineteen had smears with coexisting squamous abnormalities. Thirty patients had positive pathology, including 18 (45%) cervical intraepithelial neoplasia III (CIN III), four (10%) cervical adenocarcinoma-in situ, three (7.5%) squamous cell carcinoma of cervix, four (10%) condylomas and one (2.5%) hydatidiform mole. On review, 24 out of 32 smears with AGC 'not otherwise specified' ('NOS') had significant pathology.

CONCLUSIONS

AGC found on cervical smears during pregnancy and the postpartum period is uncommon. The chance of having significant cervical pathology, however, is high and colposcopy should be performed.

Overexpression of proto-oncogene FBI-1 activates membrane type 1-matrix metalloproteinase in association with adverse outcome in ovarian cancers

Background

FBI-1 (factor that binds to the inducer of short transcripts of human immunodeficiency virus-1) is a member of the POK (POZ and Kruppel) family of transcription factors and play important roles in cellular differentiation and oncogenesis. Recent evidence suggests that FBI-1 is expressed at high levels in a subset of human lymphomas and some epithelial solid tumors. However, the function of FBI-1 in human ovarian cancers remains elusive.

Results

In this study, we investigated the role of FBI-1 in human ovarian cancers, in particularly, its function in cancer cell invasion via modulating membrane type 1-matrix metalloproteinase (MT1-MMP). Significantly higher FBI-1 protein and mRNA expression levels were demonstrated in ovarian cancers samples and cell lines compared with borderline tumors and benign cystadenomas. Increased FBI-1 mRNA expression was correlated significantly with gene amplification (P = 0.037). Moreover, higher FBI-1 expression was found in metastatic foci (P = 0.036) and malignant ascites (P = 0.021), and was significantly associated with advanced stage (P = 0.012), shorter overall survival (P = 0.032) and disease-free survival (P = 0.016). In vitro, overexpressed FBI-1 significantly enhanced cell migration and invasion both in OVCA 420 and SKOV-3 ovarian carcinoma cells, irrespective of p53 status, accompanied with elevated expression of MT1-MMP, but not MMP-2 or TIMP-2. Moreover, knockdown of MT1-MMP abolished FBI-1-mediated cell migration and invasion. Conversely, stable knockdown of FBI-1 remarkably reduced the motility of these cells with decreased expression of MT1-MMP. Promoter assay and chromatin immunoprecipitation study indicated that FBI-1 could directly interact with the promoter spanning ~600bp of the 5'-flanking sequence of MT1-MMP and enhanced its expression in a dose-dependent manner. Furthermore, stable knockdown and ectopic expression of FBI-1 decreased and increased cell proliferation respectively in OVCA 420, but not in the p53 null SKOV-3 cells.

Conclusions

Our results suggested an important role of FBI-1 in ovarian cancer cell proliferation, cell mobility, and invasiveness, and that FBI-1 can be a potential target of chemotherapy.

Wild type and mutant 2009 pandemic influenza A (H1N1) viruses cause more severe disease and higher mortality in pregnant BALB/c mice

Background

Pregnant women infected by the pandemic influenza A (H1N1) 2009 virus had more severe disease and higher mortality but its pathogenesis is still unclear.

Principal Findings

We showed that higher mortality, more severe pneumonitis, higher pulmonary viral load, lower peripheral blood T lymphocytes and antibody responses, higher levels of proinflammatory cytokines and chemokines, and worse fetal development occurred in pregnant mice than non-pregnant controls infected by either wild type (clinical isolate) or mouse-adapted mutant virus with D222G substitution in hemagglutinin. These disease-associated changes and the lower respiratory tract involvement were worse in pregnant mice challenged by mutant virus. Though human placental origin JEG-3 cell line could be infected and proinflammatory cytokines or chemokines were elevated in amniotic fluid of some mice, no placental or fetal involvement by virus were detected by culture, real-time reverse transcription polymerase chain reaction or histopathological changes. Dual immunofluorescent staining of viral nucleoprotein and type II alveolar cell marker SP-C protein suggested that the majority of infected alveolar epithelial cells were type II pneumocytes.

Conclusion

The adverse effect of this pandemic virus on maternal and fetal outcome is largely related to the severe pulmonary disease and the indirect effect of inflammatory cytokine spillover into the systemic circulation.