Cheng Yang Chou

Calcium store sensor stromal-interaction molecule 1-dependent signaling plays an important role in cervical cancer growth, migration, and angiogenesis.

Store-operated Ca2+ entry (SOCE) is the principal Ca2+ entry mechanism in nonexcitable cells. Stromal-interaction molecule 1 (STIM1) is an endoplasmic reticulum Ca2+ sensor that triggers SOCE activation. However, the role of STIM1 in regulating cancer progression remains controversial and its clinical relevance is unclear. Here we show that STIM1-dependent signaling is important for cervical cancer cell proliferation, migration, and angiogenesis. STIM1 overexpression in tumor tissue is noted in 71% cases of early-stage cervical cancer. In tumor tissues, the level of STIM1 expression is significantly associated with the risk of metastasis and survival. EGF-stimulated cancer cell migration requires STIM1 expression and EGF increases the interaction between STIM1 and Orai1 in juxta-membrane areas, and thus induces Ca2+ influx. STIM1 involves the activation of Ca2+-regulated protease calpain, as well as Ca2+-regulated cytoplasmic kinase Pyk2, which regulate the focal-adhesion dynamics of migratory cervical cancer cells. Because of an increase of p21 protein levels and a decrease of Cdc25C protein levels, STIM1-silencing in cervical cancer cells significantly inhibits cell proliferation by arresting the cell cycle at the S and G2/M phases. STIM1 also regulates the production of VEGF in cervical cancer cells. Interference with STIM1 expression or blockade of SOCE activity inhibits tumor angiogenesis and growth in animal models, confirming the crucial role of STIM1-mediated Ca2+ influx in aggravating tumor development in vivo. These results make STIM1-dependent signaling an attractive target for therapeutic intervention.

Worldwide human papillomavirus genotype attribution in over 2000 cases of intraepithelial and invasive lesions of the vulva

BACKGROUND Human papillomavirus (HPV) contribution in vulvar intraepithelial lesions (VIN) and invasive vulvar cancer (IVC) is not clearly established. This study provides novel data on HPV markers in a large series of VIN and IVC lesions. METHODS Histologically confirmed VIN and IVC from 39 countries were assembled at the Catalan Institute of Oncology (ICO). HPV-DNA detection was done by polymerase chain reaction using SPF-10 broad-spectrum primers and genotyping by reverse hybridisation line probe assay (LiPA25) (version 1). IVC cases were tested for p16(INK4a) by immunohistochemistry (CINtec histology kit, ROCHE). An IVC was considered HPV driven if both HPV-DNA and p16(INK4a) overexpression were observed simultaneously. Data analyses included algorithms allocating multiple infections to calculate type-specific contribution and logistic regression models to estimate adjusted prevalence (AP) and its 95% confidence intervals (CI). RESULTS Of 2296 cases, 587 were VIN and 1709 IVC. HPV-DNA was detected in 86.7% and 28.6% of the cases respectively. Amongst IVC cases, 25.1% were both HPV-DNA and p16(INK4a) positive. IVC cases were largely keratinising squamous cell carcinoma (KSCC) (N=1234). Overall prevalence of HPV related IVC cases was highest in younger women for any histological subtype. SCC with warty or basaloid features (SCC_WB) (N=326) were more likely to be HPV and p16(INK4a) positive (AP=69.5%, CI=63.6-74.8) versus KSCC (AP=11.5%, CI=9.7-13.5). HPV 16 was the commonest type (72.5%) followed by HPV 33 (6.5%) and HPV 18 (4.6%). Enrichment from VIN to IVC was significantly high for HPV 45 (8.5-fold). CONCLUSION Combined data from HPV-DNA and p16(INK4a) testing are likely to represent a closer estimate of the real fraction of IVC induced by HPV. Our results indicate that HPV contribution in invasive vulvar cancer has probably been overestimated. HPV 16 remains the major player worldwide.

Epithelial-Mesenchymal Transition in Cervical Cancer: Correlation with Tumor Progression, Epidermal Growth Factor Receptor Overexpression, and Snail Up-Regulation

Purpose: Acquisition of epithelial-mesenchymal transition (EMT) by primary carcinoma cells is associated with disrupted epithelial integrity, local invasion, and ultimately metastasis. Little is known about the existence and function of EMT in cervical cancer. This study aims to investigate the regulation of EMT in cervical squamous cell carcinoma. Experimental Design: We investigated the molecular events of EMT in surgical specimens, which present the progression of cervical carcinoma. Two cervical cancer cell lines and the primary culture of normal cervical epithelia were used to study the regulatory mechanisms of EMT. Results: The chronic epidermal growth factor (EGF) treatment induces the elongation of cell shape, increases cell scattering, and enhances cell invasion. EGF treatment down-regulates E-cadherin and up-regulates vimentin in cervical cancer cells. These characteristics are consistent with the morphologic changes, molecular events, and functional significance of EMT. EGF receptor (EGFR) signaling inactivates glycogen synthase kinase-3β, which results in the nuclear accumulation of up-regulated Snail and then leads to EMT program. α5β1 integrin signaling and extracellular matrix fibronectin can modulate EGF-induced EMT. Importantly, the immunofluorescent stainings of surgical specimens indicate that cervical carcinoma progression is accompanied by EGFR overexpression, which is in parallel with decreased E-cadherin and increased vimentin. Up-regulation and nuclear accumulation of Snail correlate with EMT program in tumor tissues. Conclusion: EGF cooperates with α5β1 integrin signaling to induce EMT in cervical cancer cells via up-regulated Snail. Blockade of EGFR activity or expression may provide a potential target for the treatment of cervical cancer progression.

Cathepsin L mediates resveratrol-induced autophagy and apoptotic cell death in cervical cancer cells.

Cathepsins have long been considered as housekeeping molecules. However, specific functions have also been attributed to each one of these lysosomal proteases. Squamous cell carcinoma antigen (SCCA) 1, widely expressed in various uterine cervical cells, is an endogenous cathepsin (cat) L inhibitor. In this study, we investigated whether the cat L-SCCA 1 lysosomal pathway and autophagy were involved in resveratrol (RSV)-induced cytotoxicity in cervical cancer cells. RSV induced GFP-LC3 aggregation as well as increased the presence of LC3-II and autophagosomes as was revealed by electron microscopy in cervical cancer cells. Prolonged treatment of RSV induced cytosolic translocation of cytochrome c, caspase 3 activation, and apoptotic cell death. This apoptotic effect was abrogated by trans-epoxysuccinyl- L-leucylamido - (4-guanidino)butane, an inhibitor of cat B and L, but not by pepstatin A, an inhibitor of cat D. As cervical cancer cells express little cat B, we further studied the role of cat L. RSV induced dissipation of the lysosomal membrane permeability (LMP), leakage and increased cytosolic expression and activity of cat L. Inhibition of cat L by small interference RNA (siRNA) protected cells from RSV-induced cytotoxicity. In contrast, inhibition of SCCA 1 by siRNA promoted RSV-induced cytotoxicity. Inhibition of autophagic response by wormannin (WT) or asparagine (ASP) resulted in decreased early LC3-II formation, reduced LMP, and abolishment of the increase in RSV-induced cell death. In conclusion, we have identified a new cytotoxic mechanism in which the lysosomal enzyme cat L acts as a death signal integrator in cervical cancer cells. Furthermore, SCCA 1 may play an anti-apoptotic role through anti-cat L activity.

The KCl cotransporter isoform KCC3 can play an important role in cell growth regulation.

The KCl cotransporter (KCC) plays a significant role in the ionic and osmotic homeostasis of many cell types. Four KCC isoforms have been cloned. KCC1 and KCC4 activity is osmolality-sensitive and involved in volume regulation. KCC2, a neuronal-specific isoform, can lower intracellular Cl− and is critical for inhibitory GABA responses in the mature central nervous system. KCC3, initially cloned from vascular endothelial cells, is widely but not universally distributed and has an unknown physiological significance. Here we show a tight link between the expression and activity of KCC3 and cell growth by a NIH/3T3 fibroblast expression system. KCC3 activity is sensitive to [(dihydroindenyl)oxy] alkanoic acid (DIOA) and N-ethylmaleimide and is regulated by tyrosine phosphorylation. Osmotic swelling does not activate KCC3, and the process of regulatory volume decrease is refractory to DIOA, indicating that KCC3 is not involved in volume regulation. KCC3 expression enhances cell proliferation, and this growth advantage can be abolished by the inhibition of KCC3 by DIOA. Fluorescence-activated cell sorting measurements and Western blot analysis show DIOA caused a significant reduction of the cell fraction in proliferative phase and a change in phosphorylation of retinoblastoma protein (Rb) and cdc2, suggesting that KCC3 activity is important for cell cycle progression. Insulin-like growth factor-1 up-regulates KCC3 expression and stimulates cell growth. Tumor necrotic factor-α down-regulates KCC3 expression and causes growth arrest. These data indicate that KCC3 is an important KCC isoform that may be involved in cell proliferation.

EGF upregulates Na+/H+ exchanger NHE1 by post-translational regulation that is important for cervical cancer cell invasiveness

Na+/H+ exchanger 1 (NHE1) is involved in cell migration but little is known about the signal pathways that regulate NHE1 activity and that are associated with tumor cell invasiveness. This study is to investigate the mechanisms by which epidermal growth factor (EGF) regulates NHE1 expression to promote cervical cancer cell invasiveness and the clinical significance in early‐stage cervical cancer. NHE1 protein was scanty in normal or noncancerous cervical tissues of all surgical specimens examined (n = 92). Tumor tissues clearly expressed NHE1 protein with different amounts. The differential expression level of NHE1 is associated with the clinical outcome. NHE1 protein was also differentially expressed between normal cervical epithelial cells and two cervical cancer cell lines. Cervical cancer cells benefit some enhanced cellular functions from NHE1 abundance, such as cell volume regulation, migration, and invasion. Interestingly, NHE1 colocalized with EGF in cervical cancer tissues. Studies in cell culture systems indicated that EGF‐stimulated NHE1 abundance in a time‐dependent manner by post‐translational regulation. This implies a likely autocrine or paracrine EGF stimulation of NHE1 production in vivo. In addition, the phosphoinositide 3‐kinase pathway is the dominant signal controlling EGF‐stimulated NHE1 abundance. Pharmacological inhibition of NHE1 activity markedly inhibited the basal and EGF‐stimulated cervical cancer cell migration. Image studies and immunoprecipitaion experiments suggest that EGF‐induced NHE1 translocation to the leading‐edge lamellipodia, where NHE1 interacted with actin‐associated protein Ezrin, thereby remodeling cytoskeleton and stimulating cervical cancer cell migration. In conclusion, EGF upregulates NHE1 by post‐translational regulation that is important for cervical cancer cell invasiveness. J. Cell. Physiol. 214: 810–819, 2008.

Serum CA-125 in preoperative patients at high risk for endometriosis

OBJECTIVE To investigate the factors contributing to the elevated level of CA‐125 in endometriosis and to study whether CA‐125 assay is useful to identify women who require preoperative bowel preparation. METHODS A total of 685 women undergoing surgery for endometriosis between July 1988 and June 1999 were studied. Preoperative serum CA‐125 levels were compared between various pelvic conditions using F statistics. Multiple regression was employed to determine significant correlates of elevated serum CA‐125, and the receiver operating characteristic curve was applied to assess the utility of serum CA‐125 in preoperative preparation. Based on the two‐sample Student t test, the sample size required to detect a difference in mean serum CA‐125 levels of one‐half of one standard deviation with a power of 90% when the sample size ratio of the two groups was 1:50 was 675 with a significance level of 5%. RESULTS The mean serum CA‐125 levels (IU/mL) for American Society of Reproductive Medicine stages I, II, III, and IV endometriosis were 18.8 ± 0.9, 40.3 ± 2.8, 77.1 ± 3.5, and 182.4 ± 14.0, respectively. CA‐125 levels were significantly increased with advanced stages (P < .001, F test). Furthermore, serum CA‐125 levels were significantly higher in patients with more extensive adhesions to the peritoneum, omentum, ovary, fallopian tube, colon, and cul‐de‐sac, or with ruptured endometrioma (P < .001, F test). We then classified patients with at least one of the three factors including dense omentum adhesion, ruptured endometrioma, and complete cul‐de‐sac obliteration as the high‐risk group that required preoperative bowel preparation, and the others as the low‐risk group. Receiver operating characteristic curve analyses set a cutoff point of 65 IU/mL, which gave a sensitivity of 76%, a specificity of 71%, a positive predictive value of 76%, and a negative predictive value of 93.2%. CONCLUSION Our results suggest that preoperative CA‐125 assay is useful to decide which women should receive preoperative bowel preparation. Endometriosis patients with preoperative CA‐125 levels higher than 65 IU/mL are at high risk for severe pelvic adhesions that warrant thorough preoperative bowel preparation.

KCl cotransport is an important modulator of human cervical cancer growth and invasion

Cervical cancer is a major world health problem for women, but the pathophysiology of this disease has received scant attention. Here we show that the growth and invasion of cervical cancer cells are strongly linked the expression and activity of the KCl cotransporter (KCC), an important regulator of the ionic and cellular osmotic homeostasis. Functional assays of KCl cotransport activation by osmotic swelling, staurosporine, and N-ethylmaleimide indicate that removal of the N-terminal 117 amino acids from KCC1 produces a dominant-negative loss-of-function phenotype for KCl cotransport in human cervical cancer cells. The capability for regulatory volume decrease is much attenuated in the loss-of-function KCC mutant cervical cancer cells. The loss-of-function KCC mutant cervical cancer cells exhibit inhibited cell growth accompanied by decreased activity of the cell cycle gene products retinoblastoma and cdc2 kinase. Reduced cellular invasiveness is in parallel by reduced expression of αvβ3 and α6β4 integrins, accompanied by decreased activity of matrix metalloproteinase 2 and 9. Inhibition of tumor growth in SCID mice confirms the crucial role of KCC in promoting cervical cancer growth and invasion. Thus, blockade of KCl cotransport may be a useful therapeutic adjunctive strategy to retard or prevent cervical cancer invasion.

Human cervical cancer cells use Ca2+ signalling, protein tyrosine phosphorylation and MAP kinase in regulatory volume decrease.

1 This study was aimed at identifying the signalling pathways involved in the activation of volume‐regulatory mechanisms of human cervical cancer cells. 2 Osmotic swelling of human cervical cancer cells induced a substantial increase in intracellular Ca2+ ([Ca2+]i) by the activation of Ca2+ entry across the cell membrane, as well as Ca2+ release from intracellular stores. This Ca2+ signalling was critical for the normal regulatory volume decrease (RVD) response. 3 The activation of swelling‐activated ion and taurine transport was significantly inhibited by tyrosine kinase inhibitors (genistein and tyrphostin AG 1478) and potentiated by the tyrosine phosphatase inhibitor Na3VO4. However, the Src family of tyrosine kinases was not involved in regulation of the swelling‐activated Cl− channel. 4 Cell swelling triggered mitogen‐activated protein (MAP) kinase cascades leading to the activation of extracellular signal‐regulated kinase 1 and 2 (ERK1/ERK2) and p38 kinase. The volume‐responsive ERK1/ERK2 signalling pathway linked with the activation of K+ and Cl− channels, and taurine transport. However, the volume‐regulatory mechanism was independent of the activation of p38 MAP kinase. 5 The phosphorylated ERK1/ERK2 expression following a hypotonic shock was up‐regulated by protein kinase C (PKC) activator phorbol 12‐myristate 13‐acetate (PMA) and down‐regulated by PKC inhibitor staurosporine. The response of ERK activation to hypotonicity also required Ca2+ entry and depended on tyrosine kinase and mitogen‐activated/ERK‐activating kinase (MEK) activity. 6 Considering the results overall, osmotic swelling promotes the activation of tyrosine kinase and ERK1/ERK2 and raises intracellular Ca2+, all of which play a crucial role in the volume‐regulatory mechanism of human cervical cancer cells.

COL11A1 promotes tumor progression and predicts poor clinical outcome in ovarian cancer

Biomarkers that predict disease progression might assist the development of better therapeutic strategies for aggressive cancers, such as ovarian cancer. Here, we investigated the role of collagen type XI alpha 1 (COL11A1) in cell invasiveness and tumor formation and the prognostic impact of COL11A1 expression in ovarian cancer. Microarray analysis suggested that COL11A1 is a disease progression-associated gene that is linked to ovarian cancer recurrence and poor survival. Small interference RNA-mediated specific reduction in COL11A1 protein levels suppressed the invasive ability and oncogenic potential of ovarian cancer cells and decreased tumor formation and lung colonization in mouse xenografts. A combination of experimental approaches, including real-time RT–PCR, casein zymography and chromatin immunoprecipitation (ChIP) assays, showed that COL11A1 knockdown attenuated MMP3 expression and suppressed binding of Ets-1 to its putative MMP3 promoter-binding site, suggesting that the Ets-1–MMP3 axis is upregulated by COL11A1. Transforming growth factor (TGF)-beta (TGF-β1) treatment triggers the activation of smad2 signaling cascades, leading to activation of COL11A1 and MMP3. Pharmacological inhibition of MMP3 abrogated the TGF-β1-triggered, COL11A1-dependent cell invasiveness. Furthermore, the NF-YA-binding site on the COL11A1 promoter was identified as the major determinant of TGF-β1-dependent COL11A1 activation. Analysis of 88 ovarian cancer patients indicated that high COL11A1 mRNA levels are associated with advanced disease stage. The 5-year recurrence-free and overall survival rates were significantly lower (P=0.006 and P=0.018, respectively) among patients with high expression levels of tissue COL11A1 mRNA compared with those with low expression. We conclude that COL11A1 may promote tumor aggressiveness via the TGF-β1–MMP3 axis and that COL11A1 expression can predict clinical outcome in ovarian cancer patients.