Transforming growth factor beta1 promotes chromosomal instability in human papillomavirus 16 E6E7-infected cervical epithelial cells

Inhibition of the serine/threonine kinase BUB1 reverses taxane resistance in prostate cancer

Men with incurable castration resistant prostate cancer (CRPC) are typically treated with taxanes; however, drug resistance rapidly develops. We previously identified a clinically relevant seven gene network in aggressive CRPC, which includes the spindle assembly checkpoint (SAC) kinase BUB1. Since SAC is deregulated in taxane resistant PC, we evaluated BUB1 and found that it was over-expressed in advanced PC patient datasets and taxane resistant PC cells. Treatment with a specific BUB1 kinase inhibitor re-sensitized resistant CRPC cells, including cells expressing constitutively active androgen receptor (AR) variants, to clinically used taxanes. Consistent with a role of AR variants in taxane resistance, ectopically expressed AR-V7 increased BUB1 levels and reduced sensitivity to taxanes. This work shows that disruption of BUB1 kinase activity reverted resistance to taxanes, which is essential to advancing BUB1 as a potential therapeutic target for intractable chemotherapy resistant CRPC including AR variant driven CRPC, which lacks durable treatment options.

Tumor in the Crossfire: Inhibiting TGF-β to Enhance Cancer Immunotherapy

Cancer immunotherapy using monoclonal antibodies targeting immune checkpoints has undoubtedly revolutionized the cancer treatment landscape in the last decade. Immune checkpoint inhibitors can elicit long-lasting, previously unheard-of responses in a number of tumor entities. Yet, even in such tumors as metastatic melanoma and non-small cell-lung cancer, in which immune checkpoint inhibition has become the first-line treatment of choice, only a minority of patients will benefit considerably from these treatments. This has been attributed to a number of factors, including an immune-suppressive tumor microenvironment (TME). Using different modalities to break these barriers is of utmost importance to expand the population of patients that benefit from immune checkpoint inhibition. The multifunctional cytokine transforming growth factor-β (TGF-β) has long been recognized as an immune-suppressive factor in the TME. A considerable number of drugs have been developed to target TGF-β, yet most of these have since been discontinued. The combination of anti-TGF-β agents with immune checkpoint inhibitors now has the potential to revive this target as a viable immunomodulatory therapeutic approach. Currently, a limited number of small molecular inhibitor and monoclonal antibody candidates that target TGF-β are in clinical development in combination with the following immune checkpoint inhibitors: SRK 181, an antibody inhibiting the activation of latent TGF-β1; NIS 793, a monoclonal antibody targeting TGF-β; and SHR 1701, a fusion protein consisting of an anti-PD-L1 monoclonal antibody fused with the extracellular domain of human TGF-β receptor II. Several small molecular inhibitors are also in development and are briefly reviewed: LY364947, a pyrazole-based small molecular inhibitor of the serine-threonine kinase activity of TGFβRI; SB-431542, an inhibitor targeting several TGF-β superfamily Type I activin receptor-like kinases as well as TGF-β1-induced nuclear Smad3 localization; and galunisertib, an oral small molecular inhibitor of the TGFβRI kinase. One of the most advanced agents in this area is bintrafusp alfa, a bifunctional fusion protein composed of the extracellular domain of TGF-β receptor II fused to a human IgG1 mAb blocking PD-L1. Bintrafusp alfa is currently in advanced clinical development and as an agent in this space with the most clinical experience, is a focused highlight of this review.

The Newly Synthetized Chalcone L1 Is Involved in the Cell Growth Inhibition, Induction of Apoptosis and Suppression of Epithelial-to-Mesenchymal Transition of HeLa Cells

Over the past decades, natural products have emerged as promising agents with multiple biological activities. Many studies suggest the antioxidant, antiangiogenic, antiproliferative and anticancer effects of chalcones and their derivatives. Based on these findings, we decided to evaluate the effects of the newly synthetized chalcone L1 in a human cervical carcinoma cell (HeLa) model. Presented results were obtained by western blot and flow cytometric analyses, live cell imaging and antimigratory potential of L1 in HeLa cells was demonstrated by scratch assay. In the present study, we proved the role of L1 as an effective agent with antiproliferative activity supported by G2/M cell cycle arrest and apoptosis. Moreover, we proved that L1 is involved in modulating Transforming Growth Factor-β1 (TGF-β) signal transduction through Smad proteins and it also modulates other signalling pathways including Akt, JNK, p38 MAPK, and Erk1/2. The involvement of L1 in epithelial-to-mesenchymal transition was demonstrated by the regulation of N-cadherin, E-cadherin, and MMP-9 levels. Here, we also evaluated the effect of conditioned medium from BJ-5ta human foreskin fibroblasts in HeLa cell cultures with subsequent L1 treatment. Taken together, these data suggest the potential role of newly synthesized chalcone L1 as an anticancer-tumour microenvironment modulating agent.

Flow Cytometry Characterization of Pluripotent Transmembrane Glycoproteins on Resident Cervix Uteri Cells in Patients Screened for Cervical Cancer

The aim of this study was to characterize both by flow cytometry analysis and immunohistochemistry cervix uteri cells of nulliparous women screened for cervical intraepithelial neoplasia (CIN) in comparison to a group without CIN by using mesenchymal stem cell-like and hematopoietic lineage markers. A significant expression for CD29, CD38, HLA-I, and HLA-II was correlated positively to the CIN degree and it was more relevant in patients positive for human papilloma virus (HPV). Thus, identification and detailed characterization of pluripotent resident in uteri cells could be a promising therapeutic target.

Deciphering the Molecular Mechanism of Spontaneous Senescence in Primary Epithelial Ovarian Cancer Cells

Spontaneous senescence of cancer cells remains a puzzling and poorly understood phenomenon. Here we comprehensively characterize this process in primary epithelial ovarian cancer cells (pEOCs). Analysis of tumors from ovarian cancer patients showed an abundance of senescent cells in vivo. Further, serially passaged pEOCs become senescent after a few divisions. These senescent cultures display trace proliferation, high expression of senescence biomarkers (SA--Gal, -H2A.X), growth-arrest in the G₁ phase, increased level of cyclins D1, D2, decreased cyclin B1, up-regulated p16, p21, and p53 proteins, eroded telomeres, reduced activity of telomerase, predominantly non-telomeric DNA damage, activated AKT, AP-1, and ERK1/2 signaling, diminished JNK, NF-B, and STAT3 pathways, increased formation of reactive oxygen species, unchanged activity of antioxidants, increased oxidative damage to DNA and proteins, and dysfunctional mitochondria. Moreover, pEOC senescence is inducible by normal peritoneal mesothelium, fibroblasts, and malignant ascites via the paracrine activity of GRO-1, HGF, and TGF-1. Collectively, pEOCs undergo spontaneous senescence in a mosaic, telomere-dependent and telomere-independent manner, plausibly in an oxidative stress-dependent mechanism. The process may also be activated by extracellular stimuli. The biological and clinical significance of pEOC senescence remains to be explored.

The Intestinal Tumour Microenvironment

The tumour microenvironment (TME) of intestinal tumours is highly complex and comprises a network of stromal cells, tumour cells, immune cells and fibroblasts, as well as microorganisms. The tumour location, environmental factors and the tumour cells themselves influence the cells within the TME. Immune cells can destroy tumour cells and are associated with better patient prognosis and response to therapy; however, immune cells are highly plastic and easily influenced to instead promote tumour growth. The interaction between local immune cells and the microbiome can lead to progression or regression of intestinal tumours. In this chapter, we will discuss how tumour development and progression can influence, and be influenced by, the microenvironment surrounding it, focusing on immune and fibroblastic cells, and the intestinal microbiota, particularly in the context of colorectal cancer.

Negative roles of B7-H3 and B7-H4 in the microenvironment of cervical cancer

Although persistent human papilloma virus (HPV) infection exerts a crucial influence on cervical carcinogenesis, other factors are also involved in its development, such as intraepithelial lesions and cervical cancer. B7-H3 and B7-H4, which have been reported to be co-regulatory ligands in the B7 family, had been found to be overexpressed in cervical cancer and correlated with adverse clinicopathological features and poor prognosis in our previous studies. In this study, we sought to explore the effects of B7-H3 and B7-H4 on the cervical microenvironment. Among several immune cytokines, interleukin-10 (IL-10) and transforming growth factor (TGF) β1 stand out as important immunosuppressive factors. Our studies found that IL-10 expression increased with pathological change levels and significantly correlated with cervical cancer differentiation (P < 0.05). TGF-β1 correlated with lymph node metastasis (LNM) (P < 0.01). Expression of B7-H3 and B7-H4 positively correlated with the expression of IL-10 and TGF-β1. After co-culture, we found that overexpression of B7-H3 and B7-H4 in cervical cancer cell lines resulted in activation of the cell cycle and decreased apoptosis of U-937 cells. In addition, the contents of IL-10 and TGF-β1, as well as their protein expression levels, increased in co-culture supernatants in U-937 cells, suggesting regulation by the p-JAK2/STAT3 pathway. The in vivo results demonstrated that with the increasing expression of B7-H3/B7-H4, the expression of IL-10 and TGF-β1 also increased significantly. Overall, the expression of B7-H3 and B7-H4 favored an immunosuppressive microenvironment by promoting the production of IL-10 and TGF-β1, thereby resulting in progression of cervical carcinogenesis.

In situ expressions of protein 16 (p16CDKN2A) and transforming growth factor beta-1 in patients with cervical intraepithelial neoplasia and cervical cancer

OBJECTIVES

Protein 16 (p16^CDKN2A) and transforming growth factor-beta 1 (TGF- β1) are important tumor suppressor molecules. The aim of this study was to evaluate the frequency and simultaneous expression of p16^CDKN2A and TGF- β1 in cervical intraepithelial neoplasia (CIN) and cervical cancer and their relationship whit the neoplasia progression.

STUDY DESIGN

To evaluate the expressions of p16^CDKN2A and TGF- β1 an immunohistochemical study of both proteins in 75 cervical tissues (24 CIN I, 17 CIN II, 15 CIN III and 19 squamous cell cancer) was performed.

RESULTS

Increased expression of epithelial and stromal p16^CDKN2A in all grades of CIN and cancer was observed. Healthy controls were negative. The frequency of p16^CDKN2A expression in the patients was as follow: 75% in CIN I and 100% in CIN II, CIN III and cancer. TGF- β1 expression was found increased in all patients with CIN I and CIN II and decreased in CIN III and cancer; 60% of patients with CIN III and 16% with cancer showed reactivity for TGF- β1. High intensity of p16^CDKN2A reactivity and low intensity of TGF- β1 reactivity were observed.

CONCLUSIONS

The linear frequency of p16^CDKN2A expression accompanied by decreased frequency of TGF- β1 in CIN III and cancer could be involved in the neoplasia progression.

Human papillomavirus E6 protein enriches the CD55(+) population in cervical cancer cells, promoting radioresistance and cancer aggressiveness

Accumulating evidence indicates that the human papillomavirus (HPV) E6 protein plays a crucial role in the development of cervical cancer. Subpopulations of cells that reside within tumours are responsible for tumour resistance to cancer therapy and recurrence. However, the identity of such cells residing in cervical cancer and their relationship with the HPV-E6 protein have not been identified. Here, we isolated sphere-forming cells, which showed self-renewal ability, from primary cervical tumours. Gene expression profiling revealed that cluster of differentiation (CD) 55 was upregulated in primary cervical cancer sphere cells. Flow-cytometric analysis detected abundant CD55(+) populations among a panel of HPV-positive cervical cancer cell lines, whereas few CD55(+) cells were found in HPV-negative cervical cancer and normal cervical epithelial cell lines. The CD55(+) subpopulation isolated from the C33A cell line showed significant sphere-forming ability and enhanced tumourigenicity, cell migration, and radioresistance. In contrast, the suppression of CD55 in HPV-positive CaSki cells inhibited tumourigenicity both in vitro and in vivo, and sensitized cells to radiation treatment. In addition, ectopic expression of the HPV-E6 protein in HPV-negative cervical cancer cells dramatically enriched the CD55(+) subpopulation. CRISPR/Cas9 knockout of CD55 in an HPV-E6-overexpressing stable clone abolished the tumourigenic effects of the HPV-E6 protein. Taken together, our data suggest that HPV-E6 protein expression enriches the CD55(+) population, which contributes to tumourigenicity and radioresistance in cervical cancer cells. Targeting CD55 via CRISPR/Cas9 may represent a novel avenue for developing new strategies and effective therapies for the treatment of cervical cancer. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Somatic Host Cell Alterations in HPV Carcinogenesis

High-risk human papilloma virus (HPV) infections cause cancers in different organ sites, most commonly cervical and head and neck cancers. While carcinogenesis is initiated by two viral oncoproteins, E6 and E7, increasing evidence shows the importance of specific somatic events in host cells for malignant transformation. HPV-driven cancers share characteristic somatic changes, including apolipoprotein B mRNA editing catalytic polypeptide-like (APOBEC)-driven mutations and genomic instability leading to copy number variations and large chromosomal rearrangements. HPV-associated cancers have recurrent somatic mutations in phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) and phosphatase and tensin homolog (PTEN), human leukocyte antigen A and B (HLA-A and HLA-B)-A/B, and the transforming growth factor beta (TGFβ) pathway, and rarely have mutations in the tumor protein p53 (TP53) and RB transcriptional corepressor 1 (RB1) tumor suppressor genes. There are some variations by tumor site, such as NOTCH1 mutations which are primarily found in head and neck cancers. Understanding the somatic events following HPV infection and persistence can aid the development of early detection biomarkers, particularly when mutations in precancers are characterized. Somatic mutations may also influence prognosis and treatment decisions.

CD103+ tumor-infiltrating lymphocytes are tumor-reactive intraepithelial CD8+ T cells associated with prognostic benefit and therapy response in cervical cancer

Human papilloma virus (HPV)-induced cervical cancer constitutively expresses viral E6/E7 oncoproteins and is an excellent target for T cell-based immunotherapy. However, not all tumor-infiltrating T cells confer equal benefit to patients, with epithelial T cells being superior to stromal T cells. To assess whether the epithelial T cell biomarker CD103 could specifically discriminate the beneficial antitumor T cells, association of CD103 with clinicopathological variables and outcome was analyzed in the TCGA cervical cancer data set (n = 304) and by immunohistochemistry (IHC) in an independent cohort (n = 460). Localization of CD103+ cells in the tumor was assessed by immunofluorescence. Furthermore, use of CD103 as a response biomarker was assessed in an in vivo E6/E7+ tumor model. Our results show that CD103 gene expression was strongly correlated with cytotoxic T cell markers (e.g. CD8/GZMB/PD1) in the TCGA series. In line with this, CD103+ cells in the IHC series co-expressed CD8 and were preferentially located in cervical tumor epithelium. High CD103+ cell infiltration was strongly associated with an improved prognosis in both series, and appeared to be a better predictor of outcome than CD8. Interestingly, the prognostic benefit of CD103 in both series seemed limited to patients receiving radiotherapy. In a preclinical mouse model, HPV E6/E7-targeted therapeutic vaccination in combination with radiotherapy increased the intratumoral number of CD103+ CD8+ T cells, providing a potential mechanistic basis for our results. In conclusion, CD103 is a promising marker for rapid assessment of tumor-reactive T cell infiltration of cervical cancers and a promising response biomarker for E6/E7-targeted immunotherapy.

Extremely stringent activation of p16INK4a prevents immortalization of uterine cervical epithelial cells without human papillomavirus oncogene expression

Cervical epithelial cell immortalization with defined genetic factors without viral oncogenes has never been reported. Here we report that HPV-negative cervical epithelial cells failed to be immortalized by telomerase activation or the combination of p53 knockdown and telomerase activation. Under those conditions, p16^INK4a expression was always elevated during the late stage of limited cell lifespan, suggesting that cervical epithelial cells possess an intrinsic property of uniquely stringent activation of p16^INK4a, which may offer an explanation for the rarity of HPV-negative cervical cancer. Combining p16^INK4a knockdown with telomerase activation resulted in efficient immortalization of HPV-negative cervical epithelial cells under ordinary culture conditions. Compared with the HPV16-E6E7-immortalized cell lines derived from the same primary cell sources, the novel HPV-negative immortalized cell lines had lower degrees of chromosomal instability, maintained more sensitive p53/p21 response to DNA damage, exhibited more stringent G2 checkpoint function, and were more resistant to replication-stress-induced genomic instability. The newly immortalized HPV-negative cervical epithelial cell lines were non-tumorigenic in nude mice. The cell lines can be used not only as much-needed HPV-negative non-malignant cell models but also as starting models that can be genetically manipulated in a stepwise fashion to investigate the roles of defined genetic alterations in the development of HPV-negative cervical cancer.

Phenotype transformation of immortalized NCM460 colon epithelial cell line by TGF-β1 is associated with chromosome instability

Transforming growth factor-β1 (TGF-β1) within tumor microenvironment has a pivotal function in cancer initiation and tumorigenesis, and hence this study was to observe the malignant transformation induced by TGF-β1 in an immortalized colon epithelial cell line NCM460 for better understanding the mechanisms of colon carcinogenesis. Immortalized colon epithelial cell line NCM460 was used as the model of this study, and was treated with different concentrations of TGF-β1 for different time. Then, immunofluorescence was performed to observe the change of phenotype hallmarks including adherent junction protein E-cadherin, cytoskeleton protein vimentin, and tight junction marker ZO-1, western blotting analysis was performed to detect the expression of the above three markers and two transcription factors (Snail and Slug) involved in the transformation by TGF-β1. In addition, chromosome instability (CHI) including analysis of DNA-ploid was detected by flow cytometry. Our results revealed significant loss or reduction of ZO-1 and E-cadherin, and robust emergence of vimentin in the cell line NCM460 after a 15-, 20-, and 25-day treatment with 10 ng/ml TGF-β1. Interestingly, 20 and 25 days after stimulation with 5 ng/ml TGF-β1, expression of E-cadherin and ZO-1 revealed a pattern roughly similar to that of 10 ng/ml TGF-β1, especially, both expressions was vanished and vimentin expression was dramatically increased at days 25 after TGF-β1 stimulation. After a stimulation with 10 ng/ml TGF-β1 for 15, 20, and 25 days, the levels of Snail and Slug expression in the cells were significantly up-regulated, compared with the cells treated with TGF-β1 inhibitor LY364947, PBS or balnk control (P < 0.01). Our results found that many abnormal mitotic patterns including lagging chromosomes and anaphase bridges in NCM460 cells were induced by TGF-β1 after its stimulation for 15, 20, and 25 days. Very few mitotic cells with treatment of PBS for 15, 20 and 25 days were non-diploid whose DNA content was greater or less than 4 N, but these cells were significantly increased after exposure to TGF-β1 for 15, 20, and 25 days, which was associated with the induction of hypo-diploid, hyper-diploid, and poly-diploid (P < 0.05).These data indicate that TGF-β1 induces a phenotypic transformation of normal colon epithelium similar to its pro-tumoral behaviors in TME, involving in alteration of chromosome stability.

Transforming growth factor-β1 in carcinogenesis, progression, and therapy in cervical cancer

Transforming growth factor β1 (TGF-β1) is a multifunctional cytokine that plays important roles in cervical tumor formation, invasion, progression, and metastasis. TGF-β1 functions as a tumor inhibitor in precancerous lesions and early stage cancers of cervix whereas as a tumor promoter in later stage. This switch from a tumor inhibitor to a tumor promoter might be due to various alterations in TGF-β signaling pathway, such as mutations or loss of expression of TGF-β receptors and SMAD proteins. Additionally, the oncoproteins of human papillomaviruses have been shown to stimulate TGF-β1 expression, which in turn suppresses host immune surveillance. Thus, in addition to driving tumor cell migration and metastasis, TGF-β1 is believed to play a key role in promoting human papillomavirus infection by weakening host immune defense. In this article, we will discuss the role of TGF-β1 in the expression, carcinogenesis, progression, and therapy in cervical cancers. A better understanding of this cytokine in cervical carcinogenesis is essential for critical evaluation of this cytokine as a potential prognostic marker and therapeutic target.

Invasion of uterine cervical squamous cell carcinoma cells is facilitated by locoregional interaction with cancer-associated fibroblasts via activating transforming growth factor-beta

OBJECTIVE

Local invasion is a common pattern of spread in uterine cervical squamous cell carcinoma (CSCC). Although transforming growth factor-beta (TGF-β) facilitates invasion of various types of cancer cells, the role of the TGF-β pathway in CSCC is unclear. In this study, we analyzed the role of TGF-β signaling in the progression of CSCC.

METHODS

Immunohistochemistry was used to examine the expression of TGF-β pathway molecules in 67 CSCC samples with clinicopathological data. Activation of the TGF-β pathway was investigated following co-culture of CSCC cells and cervical cancer-associated fibroblasts (CCAFs).

RESULTS

Clinicopathological analysis of CSCC samples revealed that prominent expression of TGF-β receptor-2 was more frequent in CSCC with lymphovascular space invasion (LVSI) than without LVSI (p < 0.01). Lymph node metastasis was more frequent in cases in which phosphorylated SMAD3 (pSMAD3) was localized exclusively at the boundary of tumor clusters (n = 9, p < 0.05). Recombinant TGF-β1 increased pSMAD3 expression and enhanced cellular invasion (p < 0.005) in CSCC cells, which was attenuated by an inhibitor of the TGF-β receptor (p < 0.005). Enhanced pSMAD3 expression and invasion was also observed when conditioned media from CSCC cells co-cultured with CCAFs were administered. Luciferase assays showed that this medium contained a large amount of active TGF-β. Along with TGF-β activation, thrombospondin-1 was upregulated in both CSCC cells and CCAFs, while thrombospondin-1 silencing in either CSCC cells or CCAFs repressed the activity of TGF-β. Thrombospondin-1 was prominently expressed in cases with pSMAD3 boundary staining (p < 0.05).

CONCLUSIONS

These results suggest that interaction between CSCC cells and surrounding CCAFs activates TGF-β via thrombospondin-1 secretion to facilitate CSCC invasion.

TGFβ receptor 1: an immune susceptibility gene in HPV-associated cancer

Only a minority of those exposed to human papillomavirus (HPV) develop HPV-related cervical and oropharyngeal cancer. Because host immunity affects infection and progression to cancer, we tested the hypothesis that genetic variation in immune-related genes is a determinant of susceptibility to oropharyngeal cancer and other HPV-associated cancers by performing a multitier integrative computational analysis with oropharyngeal cancer data from a head and neck cancer genome-wide association study (GWAS). Independent analyses, including single-gene, gene-interconnectivity, protein-protein interaction, gene expression, and pathway analysis, identified immune genes and pathways significantly associated with oropharyngeal cancer. TGFβR1, which intersected all tiers of analysis and thus selected for validation, replicated significantly in the head and neck cancer GWAS limited to HPV-seropositive cases and an independent cervical cancer GWAS. The TGFβR1 containing p38-MAPK pathway was significantly associated with oropharyngeal cancer and cervical cancer, and TGFβR1 was overexpressed in oropharyngeal cancer, cervical cancer, and HPV(+) head and neck cancer tumors. These concordant analyses implicate TGFβR1 signaling as a process dysregulated across HPV-related cancers. This study demonstrates that genetic variation in immune-related genes is associated with susceptibility to oropharyngeal cancer and implicates TGFβR1/TGFβ signaling in the development of both oropharyngeal cancer and cervical cancer. Better understanding of the immunogenetic basis of susceptibility to HPV-associated cancers may provide insight into host/virus interactions and immune processes dysregulated in the minority of HPV-exposed individuals who progress to cancer.

The prognosis significance of TGF-β1 and ER protein in cervical adenocarcinoma patients with stage Ib~IIa

The incidence of stage Ib~IIa of cervical adenocarcinoma accounts about 60 to 70% of all patients. This study aims to investigate the prognostic significance of protein estrogen receptor alpha (ERα) and transforming growth factor beta 1 (TGF-β1) level in different glandular epithelia of the cervix. In this study, immunohistochemistry was used to detect ERα and TGF-β1 in carcinomas and incisal margins of 66 cases with cervical adenocarcinoma, 20 cases with normal cervix, and 20 cases with chronic cervicitis. Uni- and multivariate analysis was applied to evaluate the prognostic significance of TGF-β1 and ERα in carcinomas. The results indicated that the positive expression of TGF-β1 in carcinomas was 71.21%, significantly higher compared to that in the normal cervix (35%) and chronic cervicitis (55%) (χ(2) = 8.901, P = 0.012). Similarly, the positive expression of ERα in the carcinomas was 68.18%, significantly higher compared to the normal cervix (35%) and chronic cervicitis (50%) (χ(2) = 7.693, P = 0.021). Both TGF-β1 and ERα in the carcinomas were associated with the vaginal recurrence, infection of HPV, depth of infiltration, and lymphatic metastasis (P < 0.05). The conjugation of TGF-β1 and ERα was an independent prognostic factor for cervical adenocarcinoma. Survival curve showed that the positive TGF-β1 and ERα indicated a short lifetime of patient with cervical adenocarcinoma. In conclusion, the expression of TGF-β1 and ERα protein in the carcinomas had a significant prognostic value in a patient of stage Ib~IIa in cervical adenocarcinoma.

p21/Cyclin E pathway modulates anticlastogenic function of Bmi-1 in cancer cells

Apart from regulating stem cell self-renewal, embryonic development and proliferation, Bmi-1 has been recently reported to be critical in the maintenance of genome integrity. In searching for novel mechanisms underlying the anticlastogenic function of Bmi-1, we observed, for the first time, that Bmi-1 positively regulates p21 expression. We extended the finding that Bmi-1 deficiency induced chromosome breaks in multiple cancer cell models. Interestingly, we further demonstrated that knockdown of cyclin E or ectopic overexpression of p21 rescued Bmi-1 deficiency-induced chromosome breaks. We therefore conclude that p21/cyclin E pathway is crucial in modulating the anticlastogenic function of Bmi-1. As it is well established that the overexpression of cyclin E potently induces genome instability and p21 suppresses the function of cyclin E, the novel and important implication from our findings is that Bmi-1 plays an important role in limiting genomic instability in cylin E-overexpressing cancer cells by positive regulation of p21.

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.

Development of biomarker panel to predict, prevent and create treatments tailored to the persons with human papillomavirus-induced cervical precancerous lesions

Introduction

Human papillomavirus (HPV) induce many cancer conditions and cause cervical cancer, second in frequency of malignant disease in women.

The aim was to develop biomarker panel for HPV-induced cervical precancerous diseases in patients infected with herpes simplex virus (HSV).

Material and methods

The study involved 71 women with cervical precancerous diseases (mean age 26 ± 5 years) revealed by colposcopic, cytomorphological, and ultrasound signs which were assessed according to the following: first group, 44 patients infected with HPV; second group, 27 HPV-negative patients; and third group, 30 healthy patients (controls). In cervical specimen, we identified HPV DNA of different oncogenic risk types by polymerase chain reaction (PCR). Enzyme-linked immunosorbent assay (ELISA) kits (JSC SPC ‘DiaprofMed’) were used for detecting antibodies to HSV1 and/or HSV2 and for determining the avidity index. The production of pro-inflammatory cytokines, interferon-γ (IFN-γ), IFN-α, TNF-α, and interleukin-1β (IL-1β), and anti-inflammatory cytokines, IL-4, IL-10, and transforming growth factor-β1 (TGF-β1), were studied by ELISA.

Results

In HPV-induced cervix precancerous diseases, we identified low-avidity IgG antibodies to HSV serum of 20 patients; in the serum of 17 patients, we identified average-avidity antibodies, and high-avidity antibodies were found in 2 patients only. In 14 HPV-negative patients, we found low-avidity IgG antibodies to HSV; in 10 patients, medium avidity. Patients with low-avidity IgG antibodies to herpes virus showed high and medium oncogenic risk HPV types and a decrease of IFN-γ compared to patients with medium-avidity IgG antibodies. Production of IFN-γ was suppressed also in HPV-negative patients with cervical precancers, but we found low- and medium-avidity IgG antibodies to herpes virus. In patients with low-avidity antibodies, we observed increased level of IL-10. Level of IFN-α, IL-1β, IL-2, and IL-4 did not change in patients of all groups, but TGF-β1 increased.

Conclusions

In HPV-positive patients, those with low-avidity IgG antibodies to HSV had immunosuppression, confirmed by increased TGF-β1 and violation of IFN-γ production. Therefore, in pro- and anti-inflammatory cytokines and IgG antibodies to HSV, their avidity is an important diagnostic biomarker of HPV-induced precancerous cervical diseases. Low-avidity IgG antibodies may be an indication for treatment with immunomodulators and antiviral drugs.

Nip the HPV encoded evil in the cancer bud: HPV reshapes TRAILs and signaling landscapes

HPV encoded proteins can elicit ectopic protein–protein interactions that re-wire signaling pathways, in a mode that promotes malignancy. Moreover, accumulating data related to HPV is now providing compelling substantiation of a central role played by HPV in escaping immunosurveillance and impairment of apoptotic response. What emerges is an intricate network of Wnt, TGF, Notch signaling cascades that forms higher-order ligand–receptor complexes routing downstream signaling in HPV infected cells. These HPV infected cells are regulated both extracellularly by ligand receptor axis and intracellularly by HPV encoded proteins and impair TRAIL mediated apoptosis. We divide this review into different sections addressing how linear signaling pathways integrate to facilitate carcinogenesis and compounds that directly or indirectly reverse these aberrant interactions offer new possibilities for therapy in cancer. Although HPV encoded proteins mediated misrepresentation of pathways is difficult to target, improved drug-discovery platforms and new technologies have facilitated the discovery of agents that can target dysregulated pathways in HPV infected cervical cancer cells, thus setting the stage for preclinical models and clinical trials.

Genomic instability and colon carcinogenesis: from the perspective of genes

Colon cancer is the second most lethal cancer; approximately 600,000 people die of it annually in the world. Colon carcinogenesis generally follows a slow and stepwise process of accumulation of mutations under the influence of environmental and epigenetic factors. To adopt a personalized (tailored) cancer therapy approach and to improve current strategies for prevention, diagnosis, prognosis, and therapy overall, advanced understanding of molecular events associated with colon carcinogenesis is necessary. A contemporary approach that combines genetics, epigenomics, and signaling pathways has revealed many genetic/genomic alterations associated with colon cancer progression and their relationships to a genomic instability phenotype prevalent in colon cancer. In this review, we describe the relationship between gene mutations associated with colon carcinogenesis and a genomic instability phenotype, and we discuss possible clinical applications of genomic instability studies. Colon carcinogenesis is associated with frequent mutations in several pathways that include phosphatidylinositol 3-kinase, adenomatous polyposis coli, p53 (TP53), F-box and WD repeat domain containing 7, transforming growth factor-β, chromosome cohesion, and K-RAS. These genes frequently mutated in pathways affecting colon cancer were designated colon cancer (CAN) genes. Aberrations in major colon CAN genes have a causal relationship to genomic instability. Conversely, genomic instability itself plays a role in colon carcinogenesis in experimental settings, as demonstrated in transgenic mouse models with high genomic instability. Thus, there is a feedback-type relationship between CAN gene mutations and genomic instability. These genetic/genomic studies have led to emerging efforts to apply the knowledge to colon cancer prognosis and to targeted therapy.

Expression of HPV16 E5 down-modulates the TGFbeta signaling pathway

Background

Infection with high-risk human papillomavirus (HR-HPV) genotypes, mainly HPV16 and HPV18, is a major risk factor for cervical cancer and responsible for its progression. While the transforming role of the HPV E6 and E7 proteins is more characterized, the molecular mechanisms of the oncogenic activity of the E5 product are still only partially understood, but appear to involve deregulation of growth factor receptor expression. Since the signaling of the transforming growth factor beta (TGFbeta) is known to play crucial roles in the epithelial carcinogenesis, aim of this study was to investigate if HPV16 E5 would modulate the TGF-BRII expression and TGFbeta/Smad signaling.

Findings

The HPV16 E5 mRNA expression pattern was variable in low-grade squamous intraepithelial lesions (LSIL), while homogeneously reduced in high-grade lesions (HSIL). Parallel analysis of TGFBRII mRNA showed that the receptor transcript levels were also variable in LSILs and inversely related to those of the viral protein. In vitro quantitation of the TGFBRII mRNA and protein in human keratinocytes expressing 16E5 in a dose-dependent and time-dependent manner showed a progressive down-modulation of the receptor. Phosphorylation of Smad2 and nuclear translocation of Smad4 were also decreased in E5-expressing cells stimulated with TGFbeta1.

Conclusions

Taken together our results indicate that HPV16 E5 expression is able to attenuate the TGFbeta1/Smad signaling and propose that this loss of signal transduction, leading to destabilization of the epithelial homeostasis at very early stages of viral infection, may represent a crucial mechanism of promotion of the HPV-mediated cervical carcinogenesis.

Pericentromeric regions are refractory to prompt repair after replication stress-induced breakage in HPV16 E6E7-expressing epithelial cells

Chromosomal instability is the major form of genomic instability in cancer cells. Amongst various forms of chromosomal instability, pericentromeric or centromeric instability remains particularly poorly understood. In the present study, we found that pericentromeric instability, evidenced by dynamic formation of pericentromeric or centromeric rearrangements, breaks, deletions or iso-chromosomes, was a general phenomenon in human cells immortalized by expression of human papillomavirus type 16 E6 and E7 (HPV16 E6E7). In particular, for the first time, we surprisingly found a dramatic increase in the proportion of pericentromeric chromosomal aberrations relative to total aberrations in HPV16 E6E7-expressing cells 72 h after release from aphidicolin (APH)-induced replication stress, with pericentromeric chromosomal aberrations becoming the predominant type of structural aberrations (∼70% of total aberrations). In contrast, pericentromeric aberrations accounted for only about 20% of total aberrations in cells at the end of APH treatment. This increase in relative proportion of pericentromeric aberrations after release from APH treatment revealed that pericentromeric breaks induced by replication stress are refractory to prompt repair in HPV16 E6E7-expressing epithelial cells. Telomerase-immortalized epithelial cells without HPV16 E6E7 expression did not exhibit such preferential pericentromeric instability after release from APH treatment. Cancer development is often associated with replication stress. Since HPV16 E6 and E7 inactivate p53 and Rb, and p53 and Rb pathway defects are common in cancer, our finding that pericentromeric regions are refractory to prompt repair after replication stress-induced breakage in HPV16 E6E7-expressing cells may shed light on mechanism of general pericentromeric instability in cancer.

Establishment and characterization of a differentiated epithelial cell culture model derived from the porcine cervix uteri

Background

Cervical uterine epithelial cells maintain a physiological and pathogen-free milieu in the female mammalian reproductive tract and are involved in sperm-epithelium interaction. Easily accessible, differentiated model systems of the cervical epithelium are not yet available to elucidate the underlying molecular mechanisms within these highly specialized cells. Therefore, the aim of the study was to establish a cell culture of the porcine cervical epithelium representing in vivo-like properties of the tissue.

Results

We tested different isolation methods and culture conditions and validated purity of the cultured cells by immunohistochemistry against keratins. We could reproducibly culture pure epithelial cells from cervical tissue explants. Based on a morphology score and the WST-1 Proliferation Assay, we optimized the growth medium composition. Primary porcine cervical cells performed best in conditioned Ham's F-12, containing 10% FCS, EGF and insulin. After cultivation in an air-liquid interface for three weeks, the cells showed a discontinuously multilayered phenotype. Finally, differentiation was validated via immunohistochemistry against beta catenin. Mucopolysaccharide production could be shown via alcian blue staining.

Conclusions

We provide the first suitable protocol to establish a differentiated porcine epithelial model of the cervix uteri, based on easily accessible cells using slaughterhouse material.

High expression of TGF-β1 in the vaginal incisional margin predicts poor prognosis in patients with stage Ib-IIa cervical squamous cell carcinoma

This study evaluated the relationship between altered cytoplasmic expression of TGF-β1 in tissues of the vaginal incisional margin and vaginal cancer recurrence in patients with stage Ib-IIa cervical squamous cell carcinoma (CSCC). This paper also discusses the prognostic value of TGF-β1 expression at these locations. We found that TGF-β1 expression in the vaginal margin had a close association with vaginal recurrence of stage Ib-IIa CSCC and was an independent prognostic marker of this disease.

Genomic instability and cancer: lessons learned from human papillomaviruses

High-risk HPV E6 and E7 oncoproteins cooperate to subvert critical host cell cycle checkpoint control mechanisms in order to promote viral genome replication. This results not only in aberrant proliferation but also in host cellular changes that can promote genomic instability. The HPV-16 E7 oncoprotein was found to induce centrosome abnormalities thereby disrupting mitotic fidelity and increasing the risk for chromosome missegregation and aneuploidy. In addition, expression of the high-risk HPV E7 oncoprotein stimulates DNA replication stress as a potential source of DNA breakage and structural chromosomal instability. Proliferation of genomically unstable cells is sustained by several mechanisms including the accelerated degradation of claspin by HPV-16 E7 and the degradation of p53 by the high-risk HPV E6 oncoprotein. These results highlight the oncogenic potential of aberrant proliferation and opens new avenues for prevention of malignant progression, not only in HPV-associated cervical cancer but also in non-virally associated malignancies with disrupted cell cycle checkpoint control mechanisms.

Impact of G₂ checkpoint defect on centromeric instability

Centromeric instability is characterized by dynamic formation of centromeric breaks, deletions, isochromosomes and translocations, which are commonly observed in cancer. So far, however, the mechanisms of centromeric instability in cancer cells are still poorly understood. In this study, we tested the hypothesis that G(2) checkpoint defect promotes centromeric instability. Our observations from multiple approaches consistently support this hypothesis. We found that overexpression of cyclin B1, one of the pivotal genes driving G(2) to M phase transition, impaired G(2) checkpoint and promoted the formation of centromeric aberrations in telomerase-immortalized cell lines. Conversely, centromeric instability in cancer cells was ameliorated through reinforcement of G(2) checkpoint by cyclin B1 knockdown. Remarkably, treatment with KU55933 for only 2.5 h, which abrogated G(2) checkpoint, was sufficient to produce centromeric aberrations. Moreover, centromeric aberrations constituted the major form of structural abnormalities in G(2) checkpoint-defective ataxia telangiectasia cells. Statistical analysis showed that the frequencies of centromeric aberrations in G(2) checkpoint-defective cells were always significantly overrepresented compared with random assumption. As there are multiple pathways leading to G(2) checkpoint defect, our finding offers a broad explanation for the common occurrence of centromeric aberrations in cancer cells.

The role of inflammation in HPV carcinogenesis

The role of inflammation in human papillomavirus (HPV) infection and disease is complex since it involves responses capable of preventing initial infections, clearing those ongoing as well as promoting persistence and progression of associated lesions. Avoiding the immune response has been considered a key aspect of HPV persistence which is the main factor leading to HPV-related neoplasia. HPVs have evolved different ways of targeting immune signaling pathways. Moreover, host inflammatory response may promote lesion progression and affect tumor fate by diverse mechanisms including the direct participation of inflammatory cells. In this review, we discuss the interplay between HPV oncogenic proteins and an array of inflammatory responses that ultimately may lead to cancer.