Human papillomavirus infections and cancer stem cells of tumors from the uterine cervix

Identification of target cells of human papillomavirus 18 using squamocolumnar junction organoids

Human papillomavirus 18 (HPV18) is a highly malignant HPV genotype among high-risk HPVs, characterized by the difficulty of detecting it in precancerous lesions and its high prevalence in adenocarcinomas. The cellular targets and molecular mechanisms underlying its infection remain unclear. In this study, we aimed to identify the cells targeted by HPV18 and elucidate the molecular mechanisms underlying HPV18 replication. Initially, we established a lentiviral vector (HPV18LCR-GFP vector) containing the HPV18 long control region promoter located upstream of EGFP. Subsequently, HPV18LCR-GFP vectors were transduced into patient-derived squamocolumnar junction organoids, and the presence of GFP-positive cells was evaluated. Single-cell RNA sequencing of GFP-positive and GFP-negative cells was conducted. Differentially expressed gene analysis revealed that 169 and 484 genes were significantly upregulated in GFP-positive and GFP-negative cells, respectively. Pathway analysis showed that pathways associated with cell cycle and viral carcinogenesis were upregulated in GFP-positive cells, whereas keratinization and mitophagy/autophagy-related pathways were upregulated in GFP-negative cells. siRNA-mediated luciferase reporter assay and HPV18 genome replication assay validated that, among the upregulated genes, ADNP, FHL2, and NPM3 were significantly associated with the activation of the HPV18 early promoter and maintenance of the HPV18 genome. Among them, NPM3 showed substantially higher expression in HPV-related cervical adenocarcinomas than in squamous cell carcinomas, and NPM3 knockdown of HPV18-infected cells downregulated stem cell-related genes. Our new experimental model allows us to identify novel genes involved in HPV18 early promoter activities. These molecules might serve as therapeutic targets in HPV18-infected cervical lesions.

Role of MLH1 and MSH2 deficiency in the development of tumorigenesis and chemo-tolerance of cervical Carcinoma: Clinical implications

Cervical cancer (CACX) is one of the top causes of cancer death in women globally. The involvement of several cellular pathways in carcinogenesis is still poorly understood. Here, we focused to evaluate the contributory role of Mismatch Repair (MMR) pathway genes-MLH1 and MSH2 in CACX and their association with chemo-tolerance of the disease. For this purpose, molecular profiles (expression/promoter methylation/deletion) of the genes were analysed in both normal cervical epithelium and tumour tissue, also validated in in-silico dataset as well. Later on, prognostic importance of the genes was identified through analysis of their methylation/expression status in plasma DNA of circulating tumour cells (CTCs) and cisplatin-tolerant CACX cell lines respectively. It was found that the expression profile of MLH1 and MSH2 genes was considerably reduced from undifferentiated basal-parabasal layers of normal cervical epithelium towards progression of the disease. Further analysis showed that frequent deletion [34-48%] and promoter methylation events [28-46%] of the genes were the plausible reasons for their reduced expression during tumorigenesis. Incidentally, the prevalence of MLH1 [32%] and MSH2 [27%] promoter methylation found in CTCs of plasma of the clinically advanced CACX patients implicated their prognostic importance of the disease. In addition, the patients having high alterations of those genes resulted in poor patient outcomes even after the therapy. In in-depth analysis of this result in cisplatin-tolerant CACX cell lines, we discovered that increased promoter methylation frequency of those genes at higher concentrations of cisplatin and gradual accumulation of the cells in the G2/M phase of the cell cycle were the rational causes for their reduced expression and MMR deficiency in the system. Hence, it is possible to conclude that the gradual down-regulation of MLH1 and MSH2 proteins may be a key event for MMR pathway inactivation in CACX. This might also be associated with chemo-tolerance and overall poor survival among the patients.

Assessment and clinicopathological correlation of p16 expression in cervical squamous cell carcinoma of Indian population: Diagnostic implications

BACKGROUND

Our aim was to assess the p16 expression in normal cervical epithelium and cervical lesions and how it correlated with HPV oncoprotein E7 and other etiological parameters of cervical cancer.

METHODS

For this purpose, we analyzed protein expression of p16 and E7 oncoprotein in total 20 normal cervical epithelium tissue (as control) and 62 cervical lesions. Next, the result was correlated with different clinico-pathological parameters.

RESULTS

Out of 62 cases of cervical lesions, we found around 75%-100% of the cervical lesion samples exhibited E7 nuclear protein expression, whereas around 33.33%-75% samples were p16 positive. On the other hand, p16 expression showed strong association with E7 oncoprotein and other clinico-pathological parameters (like high parity, early age of sextual debut) in the same set of samples of our study.

CONCLUSION

We concluded that overexpression of p16 is very practical and can be readily implemented in most diagnostic pathology laboratories.

Carcinogenesis and management of human papillomavirus-associated cervical cancer

Approximately 95% of cervical cancer are caused by human papillomavirus (HPV) infection. Although it is estimated that HPV-associated cervical cancer will decrease with the widespread use of HPV vaccine, it may take time for HPV-associated cervical cancer to be eliminated. For the appropriate management of HPV-associated cervical cancer, it is important to understand the detailed mechanisms of cervical cancer development. First, the cellular origin of most cervical cancers is thought to be cells in the squamocolumnar junction (SCJ) of the uterine cervix. Therefore, it is important to understand the characteristics of SCJ for cervical cancer screening and treatment. Second, cervical cancer is caused by high risk HPV (HR-HPV) infection, however, the manner of progression to cervical cancer differs depending on the type of HR-HPV: HPV16 is characterized by a stepwise carcinogenesis, HPV18 is difficult to detect in precancerous lesions, and HPV52, 58 tends to remain in the state of cervical intraepithelial neoplasia (CIN). Third, in addition to the type of HPV, the involvement of the human immune response is also important in the progression and regression of cervical cancer. In this review, we demonstrate the carcinogenesis mechanism of HPV-associated cervical cancer, management of CIN, and the current treatment of CIN and cervical cancer.

Association of P16, Ki-67, and CD44 expression in high-grade squamous intraepithelial neoplasia and squamous cell carcinoma of the cervix

Background

Stem cells exist in niches in the cervical tissue at squamocolumnar junction, which when infected with HR-Human Papilloma Virus undergo malignant transformation to cancer stem cells and have a role in carcinogenesis and metastasis. The expression of CD44, P16, and Ki67 in high-grade squamous intraepithelial lesion (HSIL) and squamous cell carcinoma (SCC) is assessed in this study.

Materials and Methods

Twenty-six cases each of normal cervix, HSIL, and SCC of cervix cases were subjected to immunohistochemistry markers; p16, Ki-67, and CD44. The association of expression of these markers between normal, HSIL, SCC cervix, and clinic-pathological parameters was statistically analyzed. P < 0.05 was considered significant.

Results

Of 26 cases of HSIL, 61.5%, 7.7%, and 30.8% cases were positive, ambiguous, and negative respectively for p16 expression. About 11.5%, 53.8%, and 34.6% of cases were strongly positive, positive, and weakly positive, respectively, for Ki-67 expression. About 42.3%, 42.3%, and 15.4% cases were strongly positive, positive, and weakly positive, respectively, for CD44 expression. Among 26 cases of SCC of the cervix 92.3% and 7.7% were positive and ambiguous respectively. About 73.1% and 26.9% of cases were strongly positive and positive, respectively, for Ki-67 expression. 65.4%, 30.8%, and 3.8% of cases were strongly positive, positive, and weakly positive, respectively, for CD44 expression. p16, Ki-67, and CD44 expression between the three groups were statistically significant. p16 expression versus FIGO stage including lymph node involvement and CD44 expression versus lymph node involvement in carcinoma cervix was statistically significant.

Conclusion

Expression of p16, Ki-67, and CD44 increases as the lesion progress from normal to HSIL to carcinoma cervix. p16 and CD44 expression increase with lymph node involvement. P16 expression was maximum in Stage II than Stage III.

Cells with stem-like properties are associated with the development of HPV18-positive cervical cancer

The cellular origins of cervical cancer and the histological differentiation of human papillomavirus (HPV)-infected cells remain unexplained. To gain new insights into the carcinogenesis and histological differentiation of HPV-associated cervical cancer, we focused on cervical cancer with mixed histological types. We conducted genomic and transcriptomic analyses of cervical cancers with mixed histological types. The commonality of the cellular origins of these cancers was inferred using phylogenetic analysis and by assessing the HPV integration sites. Carcinogenesis was estimated by analyzing human gene expression profiles in different histological types. Among 42 cervical cancers with known HPV types, mixed histological types were detected in four cases, and three of them were HPV18-positive. Phylogenetic analysis of these three cases revealed that the different histological types had a common cell of origin. Moreover, the HPV-derived transcriptome and HPV integration sites were common among different histological types, suggesting that HPV integration could occur before differentiation into each histological type. Human gene expression profiles indicated that HPV18-positive cancer retained immunologically cold components with stem cell properties. Mixed cervical cancer has a common cellular origin among different histological types, and progenitor cells with stem-like properties may be associated with the development of HPV18-positive cervical cancer.

High nuclear expression of DNMT1 in correlation with inactivation of TET1 portray worst prognosis among the cervical carcinoma patients: clinical implications

In this study, we aimed to understand the interplay of the epigenetic modifier genes DNMT1 and TET1 along with HPV infection in the cervical epithelium and how it changes during tumorigenesis. For this purpose, initially the bioinformatical analysis (methylation and expression profile) of DNMT1 and TET1 was analyzed in the TCGA dataset. Next genetic (deletion) and epigenetic profiling (promoter methylation) of DNMT1 and TET1 were done in our sample pool and also validated in CACX cell lines as well. The results were further correlated with different clinicopathological parameters. Our data revealed that HPV infection in basal/parabasal layers of cervical epithelium actually disrupts the epigenetic homeostasis of DNMT1 and TET1 proteins which ultimately leads to the high expression of DNMT1 along with further reduction in TET1 protein during the development of carcinoma. Further, in-depth look into the results revealed that comparatively low methylation frequency of DNMT1 coupled with high promoter methylation and deletion frequency [22-46%] of TET1 were the plausible reasons of their antagonistic expression profile during the progression of the disease. Interestingly, the prevalence of DNMT1 [9.1%] and TET1 promoter methylation [22.7%] found in both the plasma DNA of the respective CACX patients implicated its diagnostic importance in this study. Lastly, molecular alteration of TET1 alone or in combination with DNMT1 showed the worst overall survival among the patients. Hence, it may be concluded that an inverse molecular profile of DNMT1 and TET1 genes seen in the proliferative basal-parabasal layers of the cervical epithelium was aggravated during the development of CACX along with genetic and epigenetic changes due to HPV infection.

Infection with high-risk genotypes of human papillomavirus and cervical cytological findings among kidney transplant recipients in Kenya: a single centre experience

BACKGROUND

High-risk human papillomavirus (hrHPV) infection is linked with uterine cervix premalignant lesions and invasive carcinoma of the uterine cervix.

METHODS

Descriptive cross sectional study carried out among female kidney transplant (KTx) recipients in Kenyatta National Hospital, Nairobi-Kenya. We studied the risk factors for acquisition of hrHPV, examined cervical cytology and assayed for 14 hrHPV DNA using Cervista® HPV HR test and Cervista® MTA (Hologic®) automated platforms.

RESULTS

The 14-hrHPV genotypes assayed were 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66, and 68 and the prevalence rate was 31.25 % (10/32). Abnormal cervical cytology was noted in 4/32 (12.5%) and included low-grade squamous intraepithelial lesion (2/32), atypical squamous cells of undetermined significance (1/32) and atypical glandular cells (1/32). The average age was 41.9 years with mean age at first coitus being 20.4 years. Majority of the women 20(62.5%) were married while 8(25%) were single. About 18(56.3%) had only one sexual partner. About 20% of women were nulliparous and 4(12.5%) had a parity of five. Duration since transplantation ranged between 1-21 years.

CONCLUSIONS

The burden of hrHPV and abnormal cervical cytology in our study seemed lower than that reported elsewhere and even in general population. This study may form basis for further studies about HPV infections and carcinoma of the uterine cervix among the kidney allograft recipients in our setting.

Differential Wnt-β- catenin pathway activation in HPV positive and negative oral epithelium is transmitted during head and neck tumorigenesis: clinical implications

The aim of this study is to understand the association of HPV infection and wnt-β-catenin self-renewal pathway in development of head and neck squamous cell carcinoma (HNSCC). For this reason, the molecular profiles (methylation/deletion/expression) of antagonists (SFRP1/2 and DKK1), agonists (FZD7 and LRP6) and effector protein β-catenin of the pathway were analyzed in HPV positive/negative oral epithelium at first, followed by its changes during development of the tumor along with correlations with different clinico-pathological parameters. HPV infection alone or in combination with tobacco habit could activate p- β-catenin expression in basal/parabasal layers of oral epithelium through high expression of FZD7 and significant down regulation of SFRP1/2 through promoter hypermethylation due to over expression of DNMT1 with ubiquitous down regulation of DKK1 and up-regulation of LRP6. This phenomenon has been seen in respective HPV positive and negative HNSCC tumors with additional deletion/microsatellite size alterations in the antagonists. Overall alterations (methylation/deletion) of SFRP1/2, DKK1 gradually increased from Group I (HPV-/Tobacco-) to Group IV(HPV+/Tobacco+) tumors, leading to the worst prognosis of the patients. Thus, the transmission of differentially activated wnt-β-catenin pathway from HPV positive/negative basal/parabasal layers of oral epithelium to HNSCC tumors determines differences in molecular pathogenesis of the disease.

Cervical cancer stem cells and other leading factors associated with cervical cancer development

Cervical cancer (CC) is one of the leading causes of cancer-associated mortalities in women from developing countries. Similar to other types of cancer, CC is considered to be a multifactorial disease, involving socioeconomic, cultural, immunological and epigenetic factors, as well as persistent human papilloma virus (HPV) infection. It has been well established that cancer stem cells (CSCs) play an important role in defining tumor size, the speed of development and the level of regression following treatment; therefore, CSCs are associated with a poor prognosis. CSCs have been detected in many types of cancer, including leukemia, pancreatic, colon, esophagus, liver, prostate, breast, gastric and lung cancer. In cervical cancer, CSCs have been associated with resistance to normally used drugs such as cisplatin. The present review summarizes the strategies that high-risk HPV viruses (HPV-16 and HPV-18) have developed to transform normal epithelial cells into cancer cells, as well as the cellular pathways and studies associated with the identification of cervical cancer stem cell biomarkers. In this sense, the present review provides state of the art information regarding CC development.

Cervical cancer stem cell-associated genes: Prognostic implications in cervical cancer

Cervical cancer is the fourth most common type of gynecological malignancy to affect females, worldwide. Although high-risk human papillomavirus (HR-HPV) infection is the primary etiologic agent associated with the development of cervical cancer, cancer stem cells (CSCs) also serve a prominent role in the development, metastasis, recurrence and prognosis of the disease. CSCs are a small subpopulation of cells that have the ability to self-renew and are present in the majority of tumors, including cervical cancer. Studies describing the phenotype of cervical CSCs (CCSCs) vary in their definition of the expression pattern of principal biomarkers, including Musashi-1, aldehyde dehydrogenase 1, Oct3/4, Sox2 and CD49f. However, these markers are not observed in all cancers, although several may be present in multiple tumor types. The present review describes the potential biomarkers of CSCs in cervical cancer. These CCSC biomarkers may serve as molecular targets to enhance the efficacy and reduce the side effects associated with chemotherapeutic treatment in HR-HPV-positive cervical cancer.

Cancer stem cell immunology and immunotherapy: Harnessing the immune system against cancer's source

Despite recent advances in diagnosis and therapy having improved cancer outcome, many patients still do not respond to treatments, resulting in the progression or relapse of the disease, eventually impairing survival expectations. The limited efficacy of therapy is often attributable to its inability to affect cancer stem cells (CSCs), a small population of cells resistant to current radio- and chemo-therapies. CSCs are characterized by self-renewal and tumor-initiating capabilities, and function as a reservoir for the local and distant recurrence of the disease. Therefore, new therapeutic approaches able to effectively target and deplete CSCs are urgently needed. Immunotherapy is facing a renewed interest for its potential in cancer treatment, and the possibility of harnessing the immune system to target CSCs is being addressed by a new exciting research field. In this chapter, we discuss the cancer stem cell model and illustrate CSC biological and molecular properties, critically addressing theoretical and practical issues linked with their definition and study. We then review the existing literature regarding the immunological properties of CSCs and the complex interplay occurring between CSCs and immune cells. Finally, we present up-to-date studies on CSC immunotargeting and its potential future perspective. In conclusion, understanding the interplay between CSC biology and tumor immunology will provide a deeper understanding of the mechanisms that regulate CSC immunological properties. This will contribute to the design of new CSC-directed immunotherapeutic strategies with the potential of strongly improving cancer outcomes.

Potential role of cancer stem cells as biomarkers and therapeutic targets in cervical cancer

BACKGROUND

Eradicating cancer stem cells (CSCs) that are termed as the "beating heart" of various malignant tumors, including cervical cancer, holds great importance in cancer therapeutics. CSCs not only confer chemo-radio resistance but also play an important role in tumor metastasis and thereby pose a potential barrier for the cure of cervical cancer. Cervical cancer, a common malignancy among females, is associated with high morbidity and mortality rates, and the study on CSCs residing in the niche is promising.

RECENT FINDINGS

Biomarker approach to screen the cervical CSCs has gained impetus since the past decade. Progress in identification and characterization of the stem cell biomarkers has led to many insights. For the diagnostic purpose, several biomarkers like viral (HPV16), stem cell markers, transcription factors (viz, SOX2, OCT 4, and c-Myc), and CSC surface markers (viz, ALDH1 and CD44) have been identified. The research so far has been directed to study the CSC stemness and demonstrates various gene expression signatures in cervical CSCs. Such studies hold a potential to improve diagnostic accuracy and predict therapeutic response and clinical outcome in patients.

CONCLUSIONS

Stem cell biomarkers have been validated and their therapeutic targets are being developed as "strategies to improve therapeutic ratio in personalized medicine." This review gives a brief overview of the cervical CSC biomarkers, their current and future diagnostic, prognostic, and therapeutic potential.

DNA mismatch repair and CD133-marked cancer stem cells in colorectal carcinoma

Background

Except for a few studies with contradictory observations, information is lacking on the possibility of association between DNA mismatch repair (MMR) status and the presence of cancer stem cells in colorectal carcinoma (CRC), two important aspects in colorectal carcinogenesis.

Methods

Eighty (40 right-sided and 40 left-sided) formalin-fixed, paraffin-embedded primary CRC were immunohistochemically studied for CD133, a putative CRC stem cell marker, and MMR proteins MLH1, MSH2, MSH6 and PMS2. CD133 expression was semi-quantitated for proportion of tumor immunopositivity on a scale of 0-5 and staining intensity on a scale of 0-3 with a final score (units) being the product of proportion and intensity of tumor staining. The tumor was considered immunopositive only when the tumor demonstrated moderate to strong intensity of CD133 staining (a decision made after analysis of CD133 expression in normal colon). Deficient MMR (dMMR) was interpreted as unequivocal loss of tumor nuclear staining for any MMR protein despite immunoreactivity in the internal positive controls.

Results

CD133 was expressed in 36 (90.0%) left-sided and 28 (70.0%) right-sided tumors (p < 0.05) and CD133 score was significantly higher in left- (mean ± SD = 9.6 ± 5.3 units) compared with right-sided tumors (mean ± SD = 6.8 ± 5.6 units) p < 0.05). dMMR was noted in 14 (35%) right-sided and no (0%) left-sided CRC. When stratified according to MMR status, dMMR cases showed a lower frequency of CD133 expression (42.9%) and CD133 score (mean ± SD = 2.5 ± 3.6 units) compared with pMMR tumors on the right (frequency = 84.6%; mean score ± SD = 9.2 ± 5.0 units) as well as pMMR tumors on the left (frequency = 90.0%; mean score ± SD = 9.6 ± 5.3 units) (p < 0.05). Interestingly, frequencies of CD133 immunoreactivity and CD133 scores did not differ between pMMR CRC on the right versus the left (p > 0.05).

Conclusion

Proficient MMR correlated with high levels of CD133-marked putative cancer stem cells in both right- and left-sided tumors, whereas significantly lower levels of CD133-marked putative cancer stem cells were associated with deficient MMR status in colorectal carcinomas found on the right.

ALDH1A1 positive cells are a unique component of the tonsillar crypt niche and are lost along with NGFR positive stem cells during tumourigenesis

Interest into the cellular biology of human tonsillar crypts has grown in recent years because it is now known to be the site of origin of most human papilloma virus (HPV) induced oropharyngeal squamous cell carcinomas (OPSCC). Despite the interest, still relatively little is known regarding the cellular hierarchy and dynamics of this anatomical subsite. Here we evaluate normal tonsillar crypts for expression of putative stem cell markers. We found that ALDH1A1 was uniquely expressed in a subset of suprabasal tonsillar crypt epithelium. This cell population was unique from NGFR expressing cells, which were previously identified to have stem/progenitor activity in vitro. In vivo mitochondrial lineage tracing was consistent with a basal to luminal progression of cellular development. This provides support for NGFR cells as the resident stem/progenitor cells in tonsillar crypts, and suggests that the ALDH1A1 cells are not stem/progenitor cells, but merely a unique component of the crypt cellular microenvironment. Analysis of tumours found that both NGFR and ALDH1A1 are lost in HPV+ and HPV- tumours, while LGR5 expression is induced in the same tumours. These results identify a unique component of the tonsillar crypt epithelium-ALDH1A1 cells-and support a cellular model where NGFR+ cells are the long-lived progenitor cells within tonsillar crypts. They also provide evidence that NGFR and ALDH1A1+ cells are lost during tumourigenesis.

Deregulation of LIMD1-VHL-HIF-1α-VEGF pathway is associated with different stages of cervical cancer

To understand the mechanism of cellular stress in basal-parabasal layers of normal cervical epithelium and during different stages of cervical carcinoma, we analyzed the alterations (expression/methylation/copy number variation/mutation) of HIF-1α and its associated genes LIMD1, VHL and VEGF in disease-free normal cervix (n = 9), adjacent normal cervix of tumors (n = 70), cervical intraepithelial neoplasia (CIN; n = 32), cancer of uterine cervix (CACX; n = 174) samples and two CACX cell lines. In basal-parabasal layers of normal cervical epithelium, LIMD1 showed high protein expression, while low protein expression of VHL was concordant with high expression of HIF-1α and VEGF irrespective of HPV-16 (human papillomavirus 16) infection. This was in concordance with the low promoter methylation of LIMD1 and high in VHL in the basal-parabasal layers of normal cervix. LIMD1 expression was significantly reduced while VHL expression was unchanged during different stages of cervical carcinoma. This was in concordance with their frequent methylation during different stages of this tumor. In different stages of cervical carcinoma, the expression pattern of HIF-1α and VEGF was high as seen in basal-parabasal layers and inversely correlated with the expression of LIMD1 and VHL. This was validated by demethylation experiments using 5-aza-2'-deoxycytidine in CACX cell lines. Additional deletion of LIMD1 and VHL in CIN/CACX provided an additional growth advantage during cervical carcinogenesis through reduced expression of genes and associated with poor prognosis of patients. Our data showed that overexpression of HIF-1α and its target gene VEGF in the basal-parabasal layers of normal cervix was due to frequent inactivation of VHL by its promoter methylation. This profile was maintained during different stages of cervical carcinoma with additional methylation/deletion of VHL and LIMD1.

Regeneration of cervical reserve cell-like cells from human induced pluripotent stem cells (iPSCs): A new approach to finding targets for cervical cancer stem cell treatment

Cervical reserve cells are epithelial progenitor cells that are pathologically evident as the origin of cervical cancer. Thus, investigating the characteristics of cervical reserve cells could yield insight into the features of cervical cancer stem cells (CSCs). In this study, we established a method for the regeneration of cervical reserve cell-like properties from human induced pluripotent stem cells (iPSCs) and named these cells induced reserve cell-like cells (iRCs). Approximately 70% of iRCs were positive for the reserve cell markers p63, CK5 and CK8. iRCs also expressed the SC junction markers CK7, AGR2, CD63, MMP7 and GDA. While iRCs expressed neither ERα nor ERβ, they expressed CA125. These data indicated that iRCs possessed characteristics of cervical epithelial progenitor cells. iRCs secreted higher levels of several inflammatory cytokines such as macrophage migration inhibitory factor (MIF), soluble intercellular adhesion molecule 1 (sICAM-1) and C-X-C motif ligand 10 (CXCL-10) compared with normal cervical epithelial cells. iRCs also expressed human leukocyte antigen-G (HLA-G), which is an important cell-surface antigen for immune tolerance and carcinogenesis. Together with the fact that cervical CSCs can originate from reserve cells, our data suggested that iRCs were potent immune modulators that might favor cervical cancer cell survival. In conclusion, by generating reserve cell-like properties from iPSCs, we provide a new approach that may yield new insight into cervical cancer stem cells and help find new oncogenic targets.

Cancer stem cells and evolving novel therapies: a paradigm shift

Accumulating evidence of stem-like cells/cancer stem cells (CSCs) has been gaining attention of cancer researchers over the last decade. Though many tumors harbor CSCs in their dedicated niches, identifying and exterminating those cells has proved to be difficult, due to their heterogenous nature, as the CSC phenotype vary substantially and may undergo reversible phenotypic changes. As a tumor propagation initiator, CSCs are considered as an exciting novel therapy for a better therapeutic outcome. This review discusses the major advances in the development of CSC-based therapies of most common cancers which includes lung, cervix and liver cancers.

Activation of Wnt-β-catenin pathway in basal-parabasal layers of normal cervical epithelium comparable during development of uterine cervical carcinoma

In this study, importance of Wnt-β-catenin pathway in the development of uterine cervical carcinoma was evaluated. For this purpose, the profiles (expression/methylation/deletion) of β-catenin, p-β-catenin (Y654), Wnt3a, and APC were studied in disease free normal cervical epithelium (n = 9), adjacent normal cervical epithelium of primary tumors (n = 70), CIN (n = 28), CACX (n = 102) samples, and two CACX cell lines (HeLa and SiHa). Immunohistochemical analysis revealed high/medium (74-95%) expression of β-catenin/p-β-catenin (Y654) and Wnt3a and low expression (23-26%) of APC in proliferating basal-parabasal layers contrary to differentiated spinous layer in normal cervix irrespective of HPV16 infection. The expression profile of the genes in the basal-parabasal layers did not change significantly during development of CACX. High (66%) promoter methylation of APC was seen in basal-parabasal layers and the cervical lesions (42-69%), unlike in spinous layers (25%). The promoter methylation status of APC was validated by in vitro demethylation experiments using 5-aza-dC in CACX cell lines. However, additional deletion of APC was significantly increased from CIN (12%) to stage I/II (40%) and became comparable in stage III/IV (48%) of the tumor. Patients with alterations (deletion/methylation) of APC and high/medium expression of Wnt3a/β-catenin/p-β-catenin (Y654) showed significantly poor survival. Thus our data indicate that cumulative effect of Wnt3a overexpression and APC inactivation are needed for overexpression of β-catenin during the development of CACX.

Photobiomodulation of breast and cervical cancer stem cells using low-intensity laser irradiation

Breast and cervical cancers are dangerous threats with regard to the health of women. The two malignancies have reached the highest record in terms of cancer-related deaths among women worldwide. Despite the use of novel strategies with the aim to treat and cure advanced stages of cancer, post-therapeutic relapse believed to be caused by cancer stem cells is one of the challenges encountered during tumor therapy. Therefore, further attention should be paid to cancer stem cells when developing novel anti-tumor therapeutic approaches. Low-intensity laser irradiation is a form of phototherapy making use of visible light in the wavelength range of 630-905 nm. Low-intensity laser irradiation has shown remarkable results in a wide range of medical applications due to its biphasic dose and wavelength effect at a cellular level. Overall, this article focuses on the cellular responses of healthy and cancer cells after treatment with low-intensity laser irradiation alone or in combination with a photosensitizer as photodynamic therapy and the influence that various wavelengths and fluencies could have on the therapeutic outcome. Attention will be paid to the biomodulative effect of low-intensity laser irradiation on cancer stem cells.

SOX2 as a New Regulator of HPV16 Transcription

Persistent infections with high-risk human papillomavirus (HPV) constitute the main risk factor for cervical cancer development. HPV16 is the most frequent type associated to squamous cell carcinomas (SCC), followed by HPV18. The long control region (LCR) in the HPV genome contains the replication origin and sequences recognized by cellular transcription factors (TFs) controlling viral transcription. Altered expression of E6 and E7 viral oncogenes, modulated by the LCR, causes modifications in cellular pathways such as proliferation, leading to malignant transformation. The aim of this study was to identify specific TFs that could contribute to the modulation of high-risk HPV transcriptional activity, related to the cellular histological origin. We identified sex determining region Y (SRY)-box 2 (SOX2) response elements present in HPV16-LCR. SOX2 binding to the LCR was demonstrated by in vivo and in vitro assays. The overexpression of this TF repressed HPV16-LCR transcriptional activity, as shown through reporter plasmid assays and by the down-regulation of endogenous HPV oncogenes. Site-directed mutagenesis revealed that three putative SOX2 binding sites are involved in the repression of the LCR activity. We propose that SOX2 acts as a transcriptional repressor of HPV16-LCR, decreasing the expression of E6 and E7 oncogenes in a SCC context.

Nitrative and oxidative DNA damage in infection-related carcinogenesis in relation to cancer stem cells

Infection and chronic inflammation have been recognized as important factors for carcinogenesis. Under inflammatory conditions, reactive oxygen species (ROS) and reactive nitrogen species (RNS) are generated from inflammatory and epithelial cells, and result in the formation of oxidative and nitrative DNA lesions, such as 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) and 8-nitroguanine. The DNA damage can cause mutations and has been implicated in inflammation-mediated carcinogenesis. It has been estimated that various infectious agents are carcinogenic to humans (IARC group 1), including bacterium Helicobacter pylori (H. pylori), viruses [hepatitis B virus (HBV), hepatitis C virus (HCV), human papillomavirus (HPV) and Epstein-Barr virus (EBV)] and parasites [Schistosoma haematobium (SH) and Opisthorchis viverrini (OV)]. H. pylori, HBV/HCV, HPV, EBV, SH and OV are important risk factors for gastric cancer, hepatocellular carcinoma, nasopharyngeal carcinoma, bladder cancer, and cholangiocarcinoma, respectively. We demonstrated that 8-nitroguanine was strongly formed via inducible nitric oxide synthase (iNOS) expression at these cancer sites of patients. Moreover, 8-nitroguanine was formed in Oct3/4-positive stem cells in SH-associated bladder cancer tissues, and in Oct3/4- and CD133-positive stem cells in OV-associated cholangiocarcinoma tissues. Therefore, it is considered that nitrative and oxidative DNA damage in stem cells may play a key role in infection-related carcinogenesis via chronic inflammation.

Association of P16-RBSP3 inactivation with phosphorylated RB1 overexpression in basal-parabasal layers of normal cervix unchanged during CACX development

To understand the molecular mechanism of RB1 phosphorylation in basal-parabasal layers of normal cervix and during cervical cancer (CACX) development, we analyzed the alterations (expression/methylation/deletion/mutation) of RB1/phosphorylated RB1 (p-RB1) (ser807/811 and ser567) and two RB1 phosphorylation inhibitors, P16 and RBSP3, in disease-free normal cervical epithelium (n = 9), adjacent normal cervical epithelium of tumors (n = 70), cervical intraepithelial neoplasia (CIN; n = 28), CACX (n = 102) samples and two CACX cell lines. Immunohistochemical analysis revealed high/medium expression of RB1/p-RB1 (ser807/811 and ser567) and low expression of P16 and RBSP3 in proliferating basal-parabasal layers of majority of normal cervical epitheliums, irrespective of HPV16 infection. Interestingly, 35-52% samples showed high/medium expression of P16 in basal-parabasal layers of normal and had significant association with deleterious non-synonimous SNPs of P16. Methylation of P16 and RBSP3 in basal-parabasal layers of normal cervix (32 and 62%, respectively) showed concordance with their respective expressions in basal-parabasal layers. The methylation frequency of P16 and RBSP3 in basal-parabasal layers of normal did not change significantly in CIN and CACX. The deletion frequency of P16 and RB1 increased significantly with CACX progression. While, deletion of RBSP3 was high in CIN and comparable during CACX progression. P16 showed scattered and infrequent mutation in CACX. The alteration of P16 and RBSP3 was synergistic and showed association with overexpression of p-RB1 in tumors and associated with poor prognosis of patients. Thus, our data suggest that overexpression of p-RB1 in basal-parabasal layers of normal cervical epithelium was due to methylation/low functional-linked non-synonimous SNPs of P16 and RBSP3. This pattern was maintained during cervical carcinogenesis by additional deletion/mutation.

Cervical cancer stem cells

The concept of cancer stem cells (CSC) has been established over the past decade or so, and their role in carcinogenic processes has been confirmed. In this review, we focus on cervical CSCs, including (1) their purported origin, (2) markers used for cervical CSC identification, (3) alterations to signalling pathways in cervical cancer and (4) the cancer stem cell niche. Although cervical CSCs have not yet been definitively identified and characterized, future studies pursuing them as therapeutic targets may provide novel insights for treatment of cervical cancer.

The Importance of Ultrasound Monitoring of the Normal and Lesional Cervical Ectropion Treatment

OBJECTIVE

to investigate the importance of various ultrasound prognosis features in the assessment of the cervical ectropion treatment monitoring.

METHOD

The inclusion criteria was the presence of ectropion and the selection was based on clinical examination performed during routine consultations in specialized clinics, later confirmed by colposcopic evaluation of cervix. The evaluation protocol included: clinical evaluation completed with colposcopy, guided biopsy when lesions were suspected, serological assay of day 21 progesteronemy, presence of Chlamydia, Mycoplasma, Ureaplasma, HVS type II, HPV and bacterial infections, transvaginal ultrasound serial evaluation at the 7th, 14th and 21st day before and after tretment concerning: cervical volumetric calculations and velocimetric measurements of uterine arteries flows. Progestative treatment was prescribed, and antiinfectious specific treatment when needed. Patients were reevaluated after 3 months.

RESULTS

The prospective study included 45 patients between 2013-2014. 28 presented serum progesterone levels below the reference range or borderline. We noted a moderate reduction of the ectropion area in 42 % and a marked reduction in 58% of the cases. No statistically significant differences were found between the size of the cervix before or after treatment, except certain evaluations (the 7th and the 14th day) in the presence of bacterial coinfections. Evaluation of pulsed Doppler velocimetric indices of uterine arteries flows showed generally minor variations with no constant positive or negative trend.

CONCLUSION

Based on the data obtained in our study, we conclude that ultrasound monitoring of ectropion treatment do not provide reliable prognosis data regarding the evolution of cervical lesion.

Conservative treatment of coexisting microinvasive squamous and adenocarcinoma of the cervix: report of two cases and literature review

Coexistence of microinvasive squamous cell carcinoma (MISCC) and microinvasive adenocarcinoma (MIAC) of the cervix is a rare phenomenon with very few clinically significant cases described in the literature. While a conservative approach has been studied, and may be effective in MISCC, a lower number of studies that recommend conservative treatment are available for MIAC. We report two cases of synchronous cervix lesions in two separate foci, MISCC and MIAC, who underwent fertility-sparing treatment with long-term follow-up. We describe clinical, histological, and immunohistochemical features of the two cases. The first case is a 41-year-old female with a diagnosis of MIAC of endocervical type, grade 1 differentiation, with a stromal invasion, associated with a separate area of squamous cell carcinoma (International Federation of Gynecology and Obstetrics/TNM stage: pT1a1G1). The second case is a 45-year-old female with a diagnosis of plurifocal MISCC, associated with an MIAC of endocervical type with a stromal invasion (International Federation of Gynecology and Obstetrics/TNM stage: pT1a1G1). After multidisciplinary counseling, both patients accepted conization as definitive treatment. Eleven years after the conization, all tests (Papanicolaou smear, colposcopy, cervical curettage, and hybrid capture 2-human papillomavirus test) planned quarterly in the first year and every 6 months in the subsequent years were negative in both patients. In women affected by stage IA1 squamous cervical cancer coexisting with stage IA1 adenocarcinoma endocervical type, with clear margins, and without lymphovascular space invasion, cervical conization may be considered a fertility-preserving, safe, and definitive therapeutic option.

Pathogenesis of human papillomavirus-associated mucosal disease

Human papillomaviruses (HPVs) are a necessary cause of carcinoma of the cervix and other mucosal epithelia. Key events in high-risk HPV (HRHPV)-associated neoplastic progression include persistent infection, deregulated expression of virus early genes in basal epithelial cells and genomic instability causing secondary host genomic imbalances. There are multiple mechanisms by which deregulated virus early gene expression may be achieved. Integration of virus DNA into host chromosomes is observed in the majority of cervical squamous cell carcinomas (SCCs), although in ∼15% of cases the virus remains extrachromosomal (episomal). Interestingly, not all integration events provide a growth advantage to basal cervical epithelial cells or lead to increased levels of the virus oncogenes E6 and E7, when compared with episome-containing basal cells. The factors that provide a competitive advantage to some integrants, but not others, are complex and include virus and host contributions. Gene expression from integrated and episomal HRHPV is regulated through host epigenetic mechanisms affecting the virus long control region (LCR), which appear to be of functional importance. New approaches to treating HRHPV-associated mucosal neoplasia include knockout of integrated HRHPV DNA, depletion of virus transcripts and inhibition of virus early gene transcription through targeting or use of epigenetic modifiers. Copyright © 2014 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Prevalence of human papillomaviruses in the healthy oral mucosa of women with high-grade squamous intra-epithelial lesion and of their partners as compared to healthy controls

Oral human papillomavirus (HPV) carriage rates were investigated in relation to genital HPV carriage in women with HPV-associated cervical lesions and male partner of such women, including several couples, in comparison with healthy individuals. Buccal and lingual mucosa of 60 males and 149 females with healthy oral mucosa and without known genital lesion, genital and oral mucosa of further 40 females with cervical high-grade squamous intraepithelial lesion (HSIL) and 34 male sexual partners of women with HSIL (including 20 couples) were sampled. HPV DNA was detected using MY/GP PCR. Genotype was determined by sequencing or restriction fragment length polymorphism. Virus copy numbers were determined by real-time PCR. Overall, oral HPV carriage rate was 5.7% (12/209) in healthy individuals; average copy number was 5.8 × 10(2) copies/1 μg DNA; male and female rates were comparable. Oral carriage in women with HSIL was significantly higher, 20.0% (8/40, P = 0.003); males with partners with HSIL showed a carriage rate of 17.6% (6/34), copy numbers were similar to the healthy controls. In contrast, genital carriage rate (52.9%, 18/34 vs. 82.5%, 33/40; P = 0.006) and average copy number were lower in males (5.0 × 10(5) vs. 7.8 × 10(5) copies/1 μg DNA; P = 0.01). Oral copy numbers in these groups and in healthy individuals were comparable. High-risk genotypes were dominant; couples usually had the same genotype in the genital sample. In conclusion, genital HPV carriage is a risk factor of oral carriage for the individual or for the sexual partner, but alone is not sufficient to produce an oral HPV infection in most cases.

Inactivation of PTCH1 is associated with the development of cervical carcinoma: clinical and prognostic implication

The aim of this study was to analyze the alterations of PTCH1 (deletion/promoter methylation/mutation/expression) during the development of cervical cancer (CACX). For this purpose, deletion/methylation of PTCH1 were analyzed in HPV16 positive exfoliated asymptomatic cervical swabs (n = 74), cervical intraepithelial neoplasia (CIN) (n = 32), CACX (n = 174) samples, and two CACX cell lines. The deletion of PTCH1 increased significantly from CIN (11.5%) to stage I/II (42%) and comparable in stage III/IV (46%). Low frequency (14-16%) of PTCH1 methylation was seen in the asymptomatic exfoliated cervical cells and in the normal epithelium adjacent to the tumor followed by a significant increase in CIN (31%) to stage I/II (57%) and comparable in stage III/IV (58%). The overall alterations (deletion/methylation) of PTCH1 significantly increased from CIN (34%) to stage I/II (70%) and comparable in stage III/IV (69%). Interestingly, in the normal epithelium, methylation of PTCH1 was high in basal/parabasal layers (83%), followed by decrease in the spinous layer (33 %), and showed significant inverse correlation with its expression. Reduced expression of PTCH1 seen in tumors showed a significant association with its alterations (deletion/methylation). The expression pattern of PTCH1 showed an inverse correlation with the nuclear expression of GLI1 in the normal epithelium as well as in the tumors. High nuclear expression of HPV16, E6, and E7 were seen in basal/parabasal layers of the normal epithelium and also in tumors. The PTCH1 alterations (deletion and/or methylation) in tumors and its methylation in adjacent normal epithelium were associated with poor prognosis of patients. Thus, our data suggests that activation of the Hedgehog pathway due to PTCH1 inactivation along with HPV infection is important in CACX development.

p16 INK4a and Ki67 expression in normal, dysplastic and neoplastic uterine cervical epithelium and human papillomavirus (HPV) infection

Cellular cycle proteins like the p16(INK4a) and the Ki67 proliferation nuclear antigen have been used as oncogenicity cellular markers. The E6 and E7 oncoproteins interact with tumor suppressor genes p53 and pRb, culminating with the p16(INK4a) overexpression. The objective of this study was to evaluate the presence of HPV-DNA in 174 cervical biopsies and correlate the different histological grades with the p16(INK4a) and Ki67 immunohistochemical expression (IHC). A cross-sectional study that enrolled a total of 174 women who underwent uterine cervical biopsies between February 2003 and December 2006, in southern Brazil, was performed. Cervical smear samples were analyzed for the presence of HPV-DNA through polymerase chain reaction (PCR), and biopsy samples were examined for p16(INK4A) and Ki67 expression through IHC techniques. The presence of HPV-DNA was observed in 89% of the tested patients, among which 52% were positive for high-risk (HR) viral types [16, 18 and 31]. Regarding p16(INK4a), an expression of 69% was observed, being expressed in 100% of the high-grade squamous lesions (HSIL) and HR-HPV-DNA positives. Ki67 expression was associated with the lesion grade, being more expressive in the most severe lesions (p<0.001). p16(INK4A) and Ki67 markers coexpression was present in 86% of the samples (p<0.001), being 100% among those positive to HR-HPV-DNA with HSIL (p<0.001). The results suggest an association between the presence of HR-HPV infection and the p16(INK4a) and Ki67 expression and which is even stronger among women with HSIL.

Shared mechanisms in stemness and carcinogenesis: lessons from oncogenic viruses

A rise in technologies for epigenetic reprogramming of cells to pluripotency, highlights the potential of understanding and manipulating cellular plasticity in unprecedented ways. Increasing evidence points to shared mechanisms between cellular reprogramming and the carcinogenic process, with the emerging possibility to harness these parallels in future therapeutics. In this review, we present a synopsis of recent work from oncogenic viruses which contributes to this body of knowledge, establishing a nexus between infection, cancer, and stemness.

Embryonic stem cell-specific signature in cervical cancer

The wide range of invasive and noninvasive lesion phenotypes associated with high-risk human papillomavirus (HR-HPV) infection in cervical cancer (CC) indicates that not only the virus but also specific cervical epithelial cells in the transformation zone (TZ), such as stem cells (SCs), play an important part in the development of cervical neoplasia. In this review, we focused in an expression signature that is specific to embryonic SCs and to poorly differentiated cervical malignant tumors and we hypothesize that this expression signature may play an important role to promote cell growth, survival, colony formation, lack of adhesion, as well as cell invasion and migration in CC.

Latent papillomavirus infections and their regulation

Model systems show that papillomavirus DNA can persist after lesion-regression, and be maintained in a subset of epithelial basal cells. These are very likely long-lived 'stem-cells' or 'stem-like cells', with latency arising via at least two distinct mechanisms. The first involves low-titre virus infection and the retention of viral DNA at levels that are too low to allow life-cycle completion. The second involves lesion-formation, and clearance by the adaptive immune system, followed by persistence with low-level viral gene expression, and possible reactivation upon immune depletion. Mechanical irritation, inflammation and other extracellular influences affect viral copy number in the latently infected cell, and may predispose to lesion-reappearance. Reactivation may account for the recurrence of 'apparently cleared' cervical lesions caused by high-risk types, the appearance of Beta HPV-lesions following immunosuppression, and the development of recurrent respiratory papillomatosis in afflicted children.