Surrogate Immunohistochemical Markers of Proliferation and Embryonic Stem Cells in Distinguishing Ameloblastoma from Ameloblastic Carcinoma

PURPOSE

The current study aimed to investigate the use of surrogate immunohistochemical (IHC) markers of proliferation and stem cells to distinguish ameloblastoma (AB) from ameloblastic carcinoma (AC).

METHODS

The study assessed a total of 29 ACs, 6 ABs that transformed into ACs, and a control cohort of 20 ABs. The demographics and clinicopathologic details of the included cases of AC were recorded. The Ki-67 proliferation index was scored through automated methods with the QuPath open-source software platform. For SOX2, OCT4 and Glypican-3 IHC, each case was scored using a proportion of positivity score combined with an intensity score to produce a total score.

RESULTS

All cases of AC showed a relatively high median proliferation index of 41.7%, with statistically significant higher scores compared to ABs. ABs that transformed into ACs had similar median proliferation scores to the control cohort of ABs. Most cases of AC showed some degree of SOX2 expression, with 58.6% showing high expression. OCT4 expression was not seen in any case of AC. GPC-3 expression in ACs was limited, with high expression in 17.2% of ACs. Primary ACs showed higher median proliferation scores and degrees of SOX2 and GPC-3 expression than secondary cases. Regarding SOX2, OCT4 and GPC-3 IHC expression, no statistically significant differences existed between the cohort of ABs and ACs.

CONCLUSION

Ki-67 IHC as a proliferation marker, particularly when assessed via automated methods, was helpful in distinguishing AC from AB cases. In contrast to other studies, surrogate IHC markers of embryonic stem cells, SOX2, OCT4 and GPC-3, were unreliable in distinguishing the two entities.

The Dynamic Changes of Transcription Factors During the Development Processes of Human Biparental and Uniparental Embryos

Previous studies have revealed that transcription factors (TFs) play important roles in biparental (BI) early human embryogenesis. However, the contribution of TFs during early uniparental embryo development is still largely unknown. Here we systematically studied the expression profiles of transcription factors in early embryonic development and revealed the dynamic changes of TFs in human biparental and uniparental embryogenesis by single-cell RNA sequencing (scRNA-seq). In general, the TF expression model of uniparental embryos showed a high degree of conformity with biparental embryos. The detailed network analysis of three different types of embryos identified that 10 out of 17 hub TFs were shared or specifically owned, such as ZNF480, ZNF581, PHB, and POU5F1, were four shared TFs, ZFN534, GTF3A, ZNF771, TEAD4, and LIN28A, were androgenic (AG) specific TFs, and ZFP42 was the only one parthenogenetic (PG) specific TF. All the four shared TFs were validated using human embryonic stem cell (hESC) differentiation experiments; most of their target genes are responsible for stem cell maintenance and differentiation. We also found that Zf-C2H2, HMG, and MYB were three dominant transcription factor families that appeared in early embryogenesis. Altogether, our work provides a comprehensive regulatory framework and better understanding of TF function in human biparental and uniparental embryogenesis.

Production of an anti-angiogenic factor sFLT1 is suppressed via promoter hypermethylation of FLT1 gene in choriocarcinoma cells

BACKGROUND

Soluble Fms-like tyrosine kinase-1 (sFLT1) as an anti-angiogenic factor is abundantly expressed in placental trophoblasts. Choriocarcinoma, a malignant tumor derived from trophoblasts, is known to be highly angiogenic and metastatic. However, the molecular mechanism underlying angiogenesis in choriocarcinoma pathogenesis remains unclear. We aimed to investigate the mRNA expression and DNA methylation status of the FLT1 gene in human choriocarcinoma cells and trophoblast cells.

METHODS

qRT-PCR, Western blotting and ELISA were conducted to evaluate the mRNA and protein expression levels of sFLT1. 5-aza-2'-deoxycytidine (5azadC) treatment and bisulfite sequencing were used to study the FLT1 gene promoter methylation. The effect of sFLT1 on choriocarcinoma growth and angiogenesis was evaluated in a xenograft mouse model.

RESULTS

Expression of the FLT1 gene was strongly suppressed in choriocarcinoma cell lines compared with that in the primary trophoblasts. Treatment of choriocarcinoma cell lines with 5azadC, a DNA methyltransferase inhibitor, markedly increased in mRNA expression of three FLT1 splice variants and secretion of sFLT1 proteins. Bisulfite sequencing revealed that the CpG hypermethylation was observed at the FLT1 promoter region in choriocarcinoma cell lines and a human primary choriocarcinoma tissue but not in human trophoblast cells. Interestingly, in 5azadC-treated choriocarcinoma cell lines, sFLT1 mRNA expression and sFLT1 production were further elevated by hypoxic stimulation. Finally, as expected, sFLT1-expressing choriocarcinoma cells implanted into nude mice showed significantly slower tumor growth and reduced microvessel formation compared with GFP-expressing control choriocarcinoma cells.

CONCLUSIONS

Inhibition of sFLT1 production by FLT1 silencing occurs via the hypermethylation of its promoter in choriocarcinoma cells. The stable expression of sFLT1 in choriocarcinoma cells resulted in the suppression of tumor growth and tumor vascularization in vivo. We suggest that the FLT1 gene may be a cell-type-specific tumor suppressor in choriocarcinoma cells.

The Stem Cell-associated Transcription Factor SOX2 as a Diagnostic Marker of High-grade Squamous Intraepithelial Lesion of the Uterine Cervix in Comparison With p16 and Ki-67

The transcription factor SOX2 has been identified as an oncogene involved in the pathogenesis of squamous cell carcinoma (SCC) of multiple sites, including the uterine cervix. The relationship between SOX2 overexpression and the continuum of precancerous lesions of the cervix has not been previously elucidated. We evaluated SOX2 immunohistochemical expression in normal cervix, low-grade squamous intraepithelial lesion (LSIL) (mild squamous dysplasia), high-grade squamous intraepithelial lesion (HSIL) (moderate and severe dysplasia) and SCC of the cervix in comparison with p16 and Ki-67. Staining patterns were scored as negative, basal one third of the epithelium, lower two third, or full thickness. The results showed that SOX2 expression was limited to the basal one third in 84% of LSIL cases, whereas 95% of HSIL showed SOX2 expression up to two third or full thickness (P<0.0001). p16 and Ki-67 displayed similar results. The difference in SOX2 expression between moderate and severe dysplasia was not statistically significant (P=0.53). Invasive SCC positivity was as follows: SOX2 94%; p16 89%; and Ki-67 100%. Our findings support a role for SOX2 in the progression of squamous dysplasia to SCC. The Lower Anogenital Standardization Terminology Project's recent assertion of a lack of a biological correlate to cervical intraepithelial neoplasia II is also upheld by SOX2. For equivocal situations in which a diagnosis of cervical intraepithelial neoplasia II would have been made, Lower Anogenital Standardization Terminology recommends p16, or other biomarkers such as Ki-67 to clarify the diagnosis. SOX2, with a clean nuclear staining pattern, may also be suitable for this role.

SOX2 promoter hypermethylation in non-smoking Taiwanese adults residing in air pollution areas

BACKGROUND

Both SOX2 promoter methylation and air pollution have been associated with lung cancer risk. However, little has been done to assess SOX2 promoter methylation in individuals living in air pollution areas. The aim of this study was to investigate SOX2 promoter methylation in non-smoking Taiwanese adults living in areas with different levels of air pollution especially particulate matter with diameter < 2.5 μm (PM2.5).

METHODS

A total of 1142 individuals aged 30-70 years were recruited. Data on SOX2 methylation, residence, age, and exposure to second-hand smoke (SHS) among others were extracted from the Taiwan Biobank dataset (2008-2015). After excluding former and current smokers, alongside those with incomplete information, a total of 461 non-smokers comprising 176 men and 285 women were included in the study. Participants' residences were grouped under northern and central/southern areas because air pollution (PM2.5) is lower in northern compared to central and southern areas.

RESULTS

The methylation levels in men (0.16310 ± 0.01230) and women (0.15740 ± 0.01240) were significantly different (P < .0001). In both sexes, the SOX2 promoter region was shown to be significantly hypermethylated in central and southern areas compared with the northern areas. The regression coefficient (β) was 0.00331 (P = 0.0257) in men and 0.00514 (P < .0001) in women.

CONCLUSION

SOX2 was significantly hypermethylated in both men and women residing in central and southern areas. The consistency in the results for both sexes shows that SOX2 promoter methylation could serve as a potential biomarker for industrial air pollution exposure. Moreover, it might reflect predisposition to cancer. Hence, healthy non-smokers at precancerous stages who have not been clinically diagnosed could be identified.

Human placental PPAR-γ and SOX-2 expression in serologically proved toxoplasmosis

To explore PPAR-γ and SOX-2 transcription factors expression in placenta according to maternal anti-Toxoplasma gondii serological profile during pregnancy and pregnancy outcome. The study included 240 placentas, grouped according to IgM and IgG serostatus and then subgrouped according to pregnancy outcome that varied between miscarriages, premature labour, stillbirth and giving birth to CNS anomaly or apparently healthy neonates. Samples were H&E stained and histopathologically scored blindly. PPAR-γ expression was measured by ELISA, while SOX-2-positive nuclei were stained immunohistochemically to be calculated by ImageJ. The mean pathological score was significantly higher in IgM+ve and IgG rising than IgG-ve and persistent low groups. Former groups showed significantly higher PPAR-γ (mean = 258.63, 227.11). However, PPAR-γ was higher in apparently healthy neonate subgroups. SOX-2 was significantly lower in IgM+ve and IgG rising groups (mean = 12.87, 43.13) and associated with obvious fibrosis. SOX-2 lowest count was in CNS anomaly subgroup. PPAR-γ and SOX-2 changes may give clues of how Toxoplasma induces pathogenesis during vertical transmission. Triggering PPAR-γ expression may be a tool to downregulate the inflammatory response and establish a metabolically permissive cellular environment for Toxoplasma persistence. Low SOX-2 is suspected to disturb placental mesenchymal stem cells pluripotency and neuroectoderm development.

Identification of microRNA signature in the progression of gestational trophoblastic disease

Gestational trophoblastic disease (GTD) encompasses a range of trophoblast-derived disorders. The most common type of GTD is hydatidiform mole (HM). Some of HMs can further develop into malignant gestational trophoblastic neoplasia (GTN). Aberrant expression of microRNA (miRNA) is widely reported to be involved in the initiation and progression of cancers. MiRNA expression profile also has been proved to be the useful signature for diagnosis, staging, prognosis, and response to chemotherapy. Till now, the profile of miRNA in the progression of GTD has not been determined. In this study, a total of 34 GTN and 60 complete HMs (CHM) trophoblastic tissues were collected. By miRNA array screening and qRT-PCR validating, six miRNAs, including miR-370-3p, -371a-5p, -518a-3p, -519d-3p, -520a-3p, and -934, were identified to be differentially expressed in GTN vs. CHM. Functional analyses further proved that miR-371a-5p and miR-518a-3p promoted proliferation, migration, and invasion of choriocarcinoma cells. Moreover, we demonstrated that miR-371a-5p was negatively related to protein levels of its predictive target genes BCCIP, SOX2, and BNIP3L, while miR-518a-3p was negatively related to MST1 and EFNA4. For the first time, we proved that miR-371a-5p and miR-518a-3p directly targeted to 3′-UTR regions of BCCIP and MST1, respectively. Additionally, we found that miR-371a-5p and miR-518a-3p regulated diverse pathways related to tumorigenesis and metastasis in choriocarcinoma cells. The results presented here may offer new clues to the progression of GTD and may provide diagnostic biomarkers for GTN.

SOX2-silenced squamous cell carcinoma: a highly malignant form of esophageal cancer with SOX2 promoter hypermethylation

This study originally aimed to investigate whether the overexpression of SOX2 is associated with the poor prognosis of patients with squamous cell carcinoma of the esophagus. However, we unexpectedly found that esophageal squamous cell carcinomas completely lacking SOX2 expression showed distinct pathologic features and highly aggressive clinical courses. The study cohort consisted of 113 consecutive patients with esophageal squamous cell carcinoma who underwent surgical resection without neoadjuvant therapy. Immunostaining on tissue microarrays and whole sections revealed that 8/113 (7%) cases were entirely negative for this transcriptional factor. SOX2-negative cancers were histologically less differentiated (P=0.002) and showed higher pT and pStages (P=0.003 and 0.007, respectively) than SOX2-positive cases. A remarkable finding was widespread lymphatic infiltration distant from the primary invasive focus, which was observed in 4 SOX2-negative cancers (50%), but none of the SOX2-positive cases. All separate dysplastic lesions observed in SOX2-negative cases were also SOX2-negative. The negative expression of SOX2 appeared to be an independent poor prognostic factor (OR=7.05, 95% CI=1.27-39.0). No mutations were identified in the coding or non-coding regions of SOX2. Fluorescent in situ hybridization did not show any copy-number variations in this gene. Since the SOX2 promoter contains an extensive CpG island, SOX2-negative cases underwent methylation-specific PCR, which disclosed promoter hypermethylation in all cases. In conclusion, SOX2-silenced squamous cell carcinomas of the esophagus appear to be a minor, but distinct form of malignancy characterized by extensive lymphatic invasion, a poor prognosis, and potential association with multiple SOX2-negative neoplastic lesions. The hypermethylation of the promoter region is seemingly a critical epigenetic event leading to SOX2 silencing.

Targeting the duality of cancer

Cancer is the second leading cause of death in the United States, and is an increasing cause of death in the developing world. While there is great heterogeneity in the anatomic site and mutations involved in human cancer, there are common features, including immortal growth, angiogenesis, apoptosis evasion, and other features, that are common to most if not all cancers. However, new features of human cancers have been found as a result of clinical use of novel “targeted therapies,” angiogenesis inhibitors, and immunotherapies, including checkpoint inhibitors. These findings indicate that cancer is a moving target, which can change signaling and metabolic features based upon the therapies offered. It is well-known that there is significant heterogeneity within a tumor and it is possible that treatment might reduce the heterogeneity as a tumor adapts to therapy and, thus, a tumor might be synchronized, even if there is no major clinical response. Understanding this concept is important, as concurrent and sequential therapies might lead to improved tumor responses and cures. We posit that the repertoire of tumor responses is both predictable and limited, thus giving hope that eventually we can be more effective against solid tumors. Currently, among solid tumors, we observe a response of 1/3 of tumors to immunotherapy, perhaps less to angiogenesis inhibition, a varied response to targeted therapies, with relapse and resistance being the rule, and a large fraction being insensitive to all of these therapies, thus requiring the older therapies of chemotherapy, surgery, and radiation. Tumor phenotypes can be seen as a continuum between binary extremes, which will be discussed further. The biology of cancer is undoubtedly more complex than duality, but thinking of cancer as a duality may help scientists and oncologists discover optimal treatments that can be given either simultaneously or sequentially.

SOX2 Inhibition Promotes Promoter Demethylation of CDX2 to Facilitate Gastric Intestinal Metaplasia

BACKGROUND

Gastric intestinal metaplasia (IM) is regarded as a premalignant lesion, conferring risks for gastric cancer development. An intestinal transcription factor, CDX2, plays a vital role in establishing and maintaining IM. SOX2, an HMG-box transcription factor, is expressed in normal gastric mucosa and downregulated in IM. Therefore, it is important to elucidate the mutual interaction of SOX2 and CDX2 in gastric IM.

AIMS

This study aims to evaluate the negative correlation between SOX2 and CDX2 in mRNA expression and promoter methylation and to illuminate the effect of SOX2 on the promoter methylation of CDX2.

METHODS

Immunohistochemistry, real-time PCR and methylation-specific polymerase chain reaction assays were performed to evaluate the expression and promoter methylation of SOX2 and CDX2 in IM tissues from patients. SOX2 knockdown and CDX2 overexpression were performed in GES-1 cells to further clarify the relationship between SOX2 and CDX2.

RESULTS

A negative correlation between SOX2 and CDX2 was found in 120 gastric IM specimens. Additionally, significant DNA demethylation of CDX2 promoter in clinical IM specimens was observed concomitantly with partial methylation of the SOX2 promoter. Furthermore, SOX2 knockdown in GES-1 cells triggered promoter demethylation of CDX2. Finally, the phenotype shift of gastric intestinal metaplasia in GES-1 cells, marked by MUC2 expression, was effectively induced by the combination of SOX2 RNAi and CDX2 overexpression.

CONCLUSIONS

Aberrant DNA methylation of SOX2 and CDX2 genes contributes to the development of IM. Notably, SOX2 may play a role in establishing and maintaining the methylation status of the CDX2 gene in gastric tissues and cells.

LINE-1 Methylation Patterns as a Predictor of Postmolar Gestational Trophoblastic Neoplasia

Objective. To study the potential of long interspersed element-1 (LINE-1) methylation change in the prediction of postmolar gestational trophoblastic neoplasia (GTN). Methods. The LINE-1 methylation pattern from first trimester placenta, hydatidiform mole, and malignant trophoblast specimens were compared. Then, hydatidiform mole patients from 11999 to 2010 were classified into the following 2 groups: a remission group and a group that developed postmolar GTN. Specimens were prepared for a methylation study. The methylation levels and percentages of LINE-1 loci were evaluated for their sensitivity, specificity, and accuracy for the prediction of postmolar GTN. Results. First, 12 placentas, 38 moles, and 19 malignant trophoblast specimens were compared. The hydatidiform mole group had the highest LINE-1 methylation level (p = 0.003) and the ^uC^uC of LINE-1 increased in the malignant trophoblast group (p ≤ 0.001). One hundred forty-five hydatidiform mole patients were classified as 103 remission and 42 postmolar GTN patients. The %^mC^uC and %^uC^mC of LINE-1 showed the lowest p value for distinguishing between the two groups (p < 0.001). The combination of the pretreatment β-hCG level (≥100,000 mIU/mL) with the %^mC^uC and %^uC^mC, sensitivity, specificity, PPV, NPV, and accuracy modified the levels to 60.0%, 92.2%, 77.4%, 83.8%, and 82.3%, respectively. Conclusions. A reduction in the partial methylation of LINE-1 occurs early before the clinical appearance of malignant transformation. The %^mC^uC and %^uC^mC of LINE-1s may be promising markers for monitoring hydatidiform moles before progression to GTN.

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.

Loss of miR-638 in vitro promotes cell invasion and a mesenchymal-like transition by influencing SOX2 expression in colorectal carcinoma cells

Background

Colorectal carcinoma (CRC) is a major cause of cancer mortality. The aberrant expression of several microRNAs is associated with CRC progression; however, the molecular mechanisms underlying this phenomenon are unclear.

Methods

miR-638 and SRY-box 2 (SOX2) expression levels were detected in 36 tumor samples and their adjacent, non-tumor tissues from patients with CRC, as well as in 4 CRC cell lines, using real-time quantitative RT-PCR (qRT-PCR). SOX2 expression levels were detected in 90 tumor samples and their adjacent tissue using immunohistochemistry. Luciferase reporter and Western blot assays were used to validate SOX2 as a target gene of miR-638. The regulation of SOX2 expression by miR-638 was assessed using qRT-PCR and Western blot assays, and the effects of exogenous miR-638 and SOX2 on cell invasion and migration were evaluated in vitro using the HCT-116 and SW1116 CRC cell lines.

Results

We found that miR-638 expression was differentially impaired in CRC specimens and dependent on tumor grade. The inhibition of miR-638 by an antagomiR promoted cell invasion and a mesenchymal-like transition (lamellipodium stretching increased and cell-cell contacts decreased, which was accompanied by the suppression of the epithelial cell marker ZO-1/E-cadherin and the upregulation of the mesenchymal cell marker vimentin). A reporter assay revealed that miR-638 repressed the luciferase activity of a reporter gene coupled to the 3′-untranslated region of SOX2. miR-638 overexpression downregulated SOX2 expression, and miR-638 inhibition upregulated SOX2 expression. Moreover, miR-638 expression levels were correlated inversely with SOX2 mRNA levels in human CRC tissues. The RNAi-mediated knockdown of SOX2 phenocopied the invasion-inhibiting effect of miR-638; furthermore, SOX2 overexpression blocked the miR-638-induced CRC cell transition to epithelial-like cells.

Conclusions

These results demonstrate that the loss of miR-638 promotes invasion and a mesenchymal-like transition by directly targeting SOX2 in vitro. These findings define miR-638 as a new, invasion-associated tumor suppressor of CRC.

Activation of endocrine-related gene expression in placental choriocarcinoma cell lines following DNA methylation knock-down

Increasingly, placental DNA methylation is assessed as a factor in pregnancy-related complications, yet the transcriptional impact of such findings is not always clear. Using a proliferative in vitro placental model, the effect of DNA methylation loss on gene activation was evaluated at a number of genes selected for being differentially methylated in pre-eclampsia-associated placentae in vivo. We aimed to determine whether reduced DNA methylation at specific loci was associated with transcriptional changes at the corresponding gene, thus providing mechanistic underpinnings for previous clinical findings and to assess the degree of transcriptional response amongst our candidate genes. BeWo and JEG3 choriocarcinoma cells were exposed to 1 μM 5-Aza-2'-deoxycytidine (5-Aza-CdR) or vehicle control for 48 h, and re-plated and cultured for a further 72 h in normal media before cells were harvested for RNA and DNA. Bisulphite pyrosequencing confirmed that DNA methylation was reduced by ∼30-50% points at the selected loci studied in both cell lines. Gene activation, measured by qRT-PCR, was highly variable and transcript specific, indicating differential sensitivity to DNA methylation. Most notably, loss of DNA methylation at the leptin (LEP) promoter corresponded to a 200-fold and 40-fold increase in LEP expression in BeWo and JEG3 cells, respectively (P < 0.01). Transcripts of steroidogenic pathway enzymes CYP11A1 and HSD3B1 were up-regulated ∼40-fold in response to 5-Aza-CdR exposure in BeWo cells (P < 0.01). Other transcripts, including aromatase (CYP19), HSD11B2, inhibin (INHBA) and glucocorticoid receptor (NR3C1) were more moderately, although significantly, affected by loss of associated DNA methylation. These data present a mixed effect of DNA methylation changes at selected loci supporting cautionary interpretation of DNA methylation results in the absence of functional data.

Isolation and characterization of human breast cancer cells with SOX2 promoter activity

Sex determining region Y-box 2 (SOX2) is well known as one of the "stemness" factors and is often expressed in cancers including breast cancer. In this study, we developed a reporter system using fluorescent protein driven by the promoter for SOX2 gene to detect and isolate living SOX2-positive cells. Using this system, we determined that SOX2 promoter activities were well correlated with SOX2 mRNA expression levels in 5 breast cancer cell lines, and that the cell population with positive SOX2 promoter activity (pSp-T(+)) isolated from one of the 5 cell lines, MCF-7 cells, showed a high SOX2 protein expression and high sphere-forming activity compared with very low promoter activity (pSp-T(low/-)). The pSp-T(+) population expressed higher mRNA levels of several stemness-related genes such as CD44, ABCB1, NANOG and TWIST1 than the pSp-T(low/-) population whereas the two populations expressed CD24 at similar levels. These results suggest that the cell population with SOX2 promoter activity contains cancer stem cell (CSC)-like cells which show different expression profiles from those of CSC-marker genes previously recognized in human breast cancers.

SOX2 overexpression correlates with poor prognosis in laryngeal squamous cell carcinoma

OBJECTIVE

The aim of present study was to investigate the expression of SOX2, a key transcription factor, in LSCC and to assess its prognostic significance.

METHODS

SOX2 expression of 161 LSCC tissues was detected by immunohistochemistry using a tissue microarray and statistically analyzed for its correlation with clinicopathological charateristics and patient outcome. In addition, SOX2 expression was also observed in 20 self-paired fresh LSCC tissues by western blot.

RESULTS

SOX2 was overexpressed in LSCC tissues as compared to the corresponding adjacent normal tissues. SOX2 expression was significantly associated with tumour T classification (p<0.001), clinical stage (p<0.001), lymph node metastasis (p=0.007) and recurrence (p=0.001). Univariate analysis revealed that patients with high SOX2 expression were significantly related to overall survival (p<0.001). Multivariate survival analysis further demonstrated that SOX2 expression was an independent prognostic factor for LSCC patients.

CONCLUSION

SOX2 may contribute to the malignant progression of laryngeal squamous cell carcinoma (LSCC), and present as a useful prognostic marker and a potential therapeutic target for LSCC patients.

HPV-16 exposed mouse embryos: a potential model for pregnancy wastage

PURPOSE

Placentas from spontaneous abortions and preterm deliveries have a higher prevalence of Human papillomavirus (HPV) compared to placentas from elective abortions and term births. The objective was to determine the effects of HPV-16 on the adhesion and implantation properties of early embryo trophoblasts.

METHODS

Two-cell mouse embryos were cultured (medium G2, 5 % CO2, 37 °C) for 72-96 h and exposed to either HPV-16 rich SiHa cell lysates which were refrigerated after mechanical lysis, thawed lysates which had been frozen for freeze/thaw lysis method, or control medium, incubated (4-5 days) and evaluated by microscopy (N = 96 embryos, 3 repeated experiments). Trophoblasts were stained and images were digitized. Adhesion and dimension data were analyzed by Chi-square and t test, respectively.

RESULTS

HPV-16 exposed embryos exhibited less adhesion through reduced implantation compared with the control (combined lysates 53.8 vs. 85.7 %, P < 0.05). Refrigerated and thawed lysate groups had similar reduced implantations (58.3 vs. 50.0 %). Of the embryos with implantation, 100 % in the refrigerated lysates were noted to have loose or abnormal adhesion. This was measured when embryos were noted to be lost after washes with HTF. There was no difference in trophoblast viability among the groups. Total trophoblast area was greater in the HPV-16 exposed frozen lysate group (1,881.8 ± 605.3 vs. control 848.8 ± 298.0 square units, mean ± SEM).

CONCLUSIONS

HPV-16 inhibited trophoblasts adhesion needed for normal implantation, but not embryo development. Total trophoblast spread was increased after HPV-16 exposure suggesting that HPV-16 altered trophoblast migration. These results suggest that HPV-16 may induce abnormal placental growth resulting in pregnancy wastage.

Application of a NotI subtraction and methylation‑specific genome subtractive hybridization technique in the detection of genomic DNA methylation differences between hydatidiform moles and villi

Previous studies indicate that epigenetic modifications play an important role in transcriptional regulation and contribute to the pathogenesis of gestational trophoblastic disease, including complete hydatidiform moles (CHMs). However, the underlying mechanisms and the critical genes have not been clearly identified. In the present study, we developed a novel technique, NotI subtraction and methylation-specific genome subtractive hybridization (MS-G-SH), as a method of screening for methylation changes between hydatidiform moles and villi. Following NotI subtraction and hybridization, three different positive DNA clones were found in 110 random clones of DNA samples. Most importantly, two DNA clones having long CpG islands and high homology with exons of insulin-like growth factor 2 (IGF2) and transforming growth factor-β (TGF-β) were identified using bioinformatic tools. After bisulfite treatment and methylation-specific PCR, the specific methylation of certain exons of IGF2 and TGF-β was identified. In addition, the mRNA expression levels of these two genes were markedly different. In conclusion, this novel MS-G-SH technique is an alternative and effective approach for the detection of specific DNA methylation.

Cell proliferation and invasion ability of human choriocarcinoma cells lessened due to inhibition of Sox2 expression by microRNA-145

To date, the mechanism underlying the development of human choriocarcinomas has not been elucidated. It is hypothesized that the Sox2 protein plays a pivotal role in the proliferation and invasion capacity of tumor cells. A microRNA (miR-145) was cloned and used to study the expression of Sox2 and its regulatory effect on the proliferation and invasion capacity of the human choriocarcinoma cell line JAR. In the present study, Sox2 mRNA and protein expression decreased in JAR and JEG-3 cells following transfection with the miR-145 expression virus. Cell proliferation assays indicated that miR-145 expression affected cell cycle regulation and suppressed the proliferation of choriocarcinoma cells in vitro. In addition, xenograft experiments confirmed the suppression of tumor growth in vivo due to cell cycle arrest. Therefore, endogenous mature miR-145 expression may have an important role in the pathogenesis of human choriocarcinomas via interference with the Sox2 target gene by epigenetic modification. This information is of potential significance for the identification of therapeutic targets in human choriocarcinoma.

Establishment of a choriocarcinoma model from immortalized normal extravillous trophoblast cells transduced with HRASV12

Gestational choriocarcinoma is a malignant trophoblastic tumor. The development of novel molecular-targeted therapies is needed to reduce the toxicity of current multiagent chemotherapy and to treat successfully the chemoresistant cases. The molecular mechanisms underlying choriocarcinoma tumorigenesis remain uncharacterized, however, and appropriate choriocarcinoma animal models have not yet been developed. In this study, we established a choriocarcinoma model by inoculating mice with induced-choriocarcinoma cell-1 (iC³-1) cells, generated from HTR8/SVneo human trophoblastic cells retrovirally transduced with activated H-RAS (HRASV12). The iC³-1 cells exhibited constitutive activation of the mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K) pathways and developed into lethal tumors in all inoculated mice. Histopathological analysis revealed that the tumors consisted of two distinct types of cells, reminiscent of syncytiotrophoblasts and cytotrophoblasts, as seen in the human choriocarcinoma. The tumors expressed HLA-G and cytokeratin (trophoblast markers) and hCG (a choriocarcinoma marker). Comparative analysis of gene expression profiles between iC³-1 cells and parental HTR8/SVneo cells revealed that iC³-1 cells expressed matrix metalloproteinases, epithelial-mesenchymal transition-related genes, and SOX3 at higher levels than parental trophoblastic cells. Administration of SOX3-specific short-hairpin RNA decreased SOX3 expression and attenuated the tumorigenic activity of iC³-1 cells, suggesting that SOX3 overexpression might be critically involved in the pathogenesis of choriocarcinoma. Our murine model represents a potent new tool for studying the pathogenesis and treatment of choriocarcinoma.

Downregulation of ASPP1 in gestational trophoblastic disease: correlation with hypermethylation, apoptotic activity and clinical outcome

Gestational trophoblastic disease encompasses a spectrum of trophoblastic lesions including true neoplasms such as choriocarcinomas and the potentially malignant hydatidiform moles, which may develop persistent disease requiring chemotherapy. ASPP1, a member of apoptosis-stimulating proteins of p53 (ASPPs), is a proapoptotic protein that can stimulate apoptosis through its interaction with p53. We evaluated the promoter methylation and expression profiles of ASPP1 in different trophoblastic tissues and its in vitro functional effect on two choriocarcinoma cell lines, namely JEG-3 and JAR. Significant downregulation of ASPP1 mRNA and protein levels was demonstrated in hydatidiform moles and choriocarcinomas, when compared with normal placentas by quantitative-PCR and immunohistochemistry. The ASPP1 mRNA level was significantly correlated with its hypermethylation status, evaluated with methylation-specific PCR, in placenta and gestational trophoblastic disease samples (P=0.024). Moreover, lower ASPP1 immunoreactivity was shown in hydatidiform moles that progressed to persistent gestational trophoblastic neoplasms than in those that regressed (P=0.045). A significant correlation was also found between expression of ASPP1 and proliferative indices (assessed by Ki67 and MCM7), apoptotic activity (M30 CytoDeath antibody), p53 and caspase-8 immunoreactivities. An in vitro study showed that ectopic expression of ASPP1 could trigger apoptosis through intrinsic and extrinsic pathways as indicated by an increase in cleaved caspase-9 and Fas ligand protein expression. The latter suggests a hitherto unreported novel link between ASPP1 and the extrinsic pathway of apoptosis. Our findings suggest that downregulation of ASPP1 by hypermethylation may be involved in the pathogenesis and progress of gestational trophoblastic disease, probably through its effect on apoptosis.

Expression of Sox2 in human cervical carcinogenesis

Sox2 is a key transcription factor for embryonic development and plays a critical role in determining the fate of stem cells. Recently, Sox2 has been detected in several human tumors, indicating a potential function in tumorigenesis. We initially reported remarkably increased nuclear Sox2 staining in cervical carcinomas compared with normal cervix (P < .05). Furthermore, Sox2 staining was detected in most tumorsphere cells isolated from fresh cervical cancer tissues but not among the differentiated tumorsphere cells. When Sox2 was stably expressed in cervical cancer cells (SiHa and HeLa), Sox2-overexpressing cells had increased proliferation, clonogenicity, and tumorigenicity in vitro and in vivo than control cells. These results suggest that Sox2 may participate in carcinogenesis of cervical carcinomas and may be a potential therapeutic target molecule for cervical cancers.

Hypermethylation of SOX2 Promoter in Endometrial Carcinogenesis

This paper aimed at investigating the expression and methylation profiles of SOX2, a gene coding for the stem cell-related transcription factor SOX2, in endometrial carcinomas. By methylation-specific polymerase chain reaction (MS-PCR), the methylation status of SOX2 promoter region in 72 endometrial carcinomas and 12 normal endometrial samples was examined. Methylated allele was found in 37.5% (27/72) of endometrial carcinomas but only in 8.3% (1/12) of normal endometrial, significantly more frequent in cancers (P = .0472). SOX2 mRNA level was significantly reduced in endometrial carcinoma compared with nonneoplastic endometrium (P = .045). A significant correlation between SOX2 mRNA expression and hypermethylation of SOX2 was found (P = .024). Hypermethylation of SOX2 tended to be more frequently found in type II serous or clear cell adenocarcinoma. SOX2 methylation was also significantly correlated with shorter survival of patients (P = .046). In conclusion, epigenetic mechanisms may play a crucial role on the transcriptional regulation of SOX2 and loss of SOX2 expression may be related to endometrial carcinogenesis.

Tyrosine kinase B receptor and BDNF expression in ovarian cancers - Effect on cell migration, angiogenesis and clinical outcome

In this report, we demonstrated that overexpression of tropomyosin-related kinase B (TrkB) was associated with shorter survival in ovarian cancer patients. Brain-derived neurotrophic factor (BDNF), the TrkB ligand, induced activation (phosphorylation) of TrkB in a dose dependent manner. Besides demonstrating the effect of BDNF/TrkB pathway in enhancing cancer cell migration and invasion but inhibiting apoptosis, we also report for the first time that exogenous hepatocyte growth factor induced TrkB expression at both mRNA and protein levels as well as phosphorylation. Our findings suggest that BDNF/TrkB pathway is important in ovarian carcinogenesis and TrkB may be a potential therapeutic target for ovarian cancer.

Pathogenesis of choriocarcinoma: clinical, genetic and stem cell perspectives

Choriocarcinoma is a unique malignant neoplasm composed of mononuclear cytotrophoblasts and multinucleated syncytiotrophoblasts that produce human chorionic gonadotrophin. Choriocarcinoma can occur after a pregnancy, as a component of germ cell tumors, or in association with a poorly differentiated somatic carcinoma, each with distinct clinical features. Cytogenetic and molecular studies, predominantly on gestational choriocarcinoma, revealed the impact of oncogenes, tumor suppressor genes and imprinting genes on its pathogenesis. The role of stem cells in various types of choriocarcinoma has been studied recently. This review will discuss how such knowledge can enhance our understanding of the pathogenesis of choriocarcinoma, enable exploration of novel anti-choriocarcinoma targeted therapy and possibly improve our insight on embryological and placental development.