Metformin induces ZFP36 by mTORC1 inhibition in cervical cancer-derived cell lines.

BACKGROUND: Metformin, a widely prescribed antidiabetic drug, has shown several promising effects for cancer treatment. These effects have been shown to be mediated by dual modulation of the AMPK-mTORC1 axis, where AMPK acts upstream of mTORC1 to decrease its activity. Nevertheless, alternative pathways have been recently discovered suggesting that metformin can act through of different targets regulation. METHODS: We performed a transcriptome screening analysis using HeLa xenograft tumors generated in NOD-SCID mice treated with or without metformin to examine genes regulated by metformin. Western Blot analysis, Immunohistochemical staining, and RT-qPCR were used to confirm alterations in gene expression. The TNMplot and GEPIA2 platform were used for in silico analysis of genes found up-regulated by metformin, in cervical cancer patients. We performed an AMPK knock-down using AMPK-targeted siRNAs and mTOR inhibition with rapamycin to investigate the molecular mechanisms underlying the effect of metformin in cervical cancer cell lines. RESULTS: We shown that metformin decreases tumor growth and increased the expression of a group of antitumoral genes involved in DNA-binding transcription activator activity, hormonal response, and Dcp1-Dcp2 mRNA-decapping complex. We demonstrated that ZFP36 could act as a new molecular target increased by metformin. mTORC1 inhibition using rapamycin induces ZFP36 expression, which could suggest that metformin increases ZFP36 expression and requires mTORC1 inhibition for such effect. Surprisingly, in HeLa cells AMPK inhibition did not affect ZFP36 expression, suggesting that additional signal transducers related to suppressing mTORC1 activity, could be involved. CONCLUSIONS: These results highlight the importance of ZFP36 activation in response to metformin treatment involving mTORC1 inhibition.

Prevalence of anal high-risk human papillomavirus (HR-HPV) types in people living with HIV and a history of cancer.

This study aimed to describe the prevalence of high-risk human papillomavirus (HR-HPV) types in the anal canal in a cohort of people living with HIV (PLWHIV) with a history of malignancy. SETTING: Referral tertiary care hospital for adult patients with cancer. METHODS: We reviewed data of patients from the AIDS Cancer Clinic on antiretroviral therapy in chronic control who were consecutively referred for high-resolution anoscopy (HRA), where they underwent anal evaluation, collection of specimens for anal cytology and anal human papillomavirus (HPV) followed by HRA with directed biopsy if needed. RESULTS: A total of 155 patients were included; 149 (96.1%) were men, all of them men who have sex with men (MSM); the median age was 39 (IQR 32-47) years; 105 (67.7%) with Kaposi sarcoma, 40 (25.8%) with non-Hodgkin lymphoma and 10 (6.4%) with other neoplasms; only 7 (4.5%) had active cancer. The prevalence of HR-HPV infection was 89% (n=138) (95% CI 83-93) with at least one HR-HPV infection, and 62% (96) had coinfection with at least two types; the median HR-HPV types of coinfection were 3 (IQR 2-4). The number of patients infected with HPV 16 was 64 (41.3%, 95% CI 33.8-49.3), HPV 18 was 74 (47.7%, 95% CI 39.9-55.7) and with both 35 (22.6%). Some 59 patients (38%) had high-grade squamous intraepithelial lesions (HSIL) and 49 (31.6%) had low-grade squamous intraepithelial lesions (LSIL). The prevalence of HR-HPV and HSIL among patients aged ≤35 and >35 years was the same. CONCLUSIONS: In this cohort of PLWHIV with a history of malignancy we found a high prevalence of HR-HPV 16 and 18 and anal HSIL, even in persons aged ≤35 years. These data highlight the importance of anal cancer screening in PLWHIV and history of malignancy.

Mutant p53 gain-of-function stimulates canonical Wnt signaling via PI3K/AKT pathway in colon cancer.

Aberrant canonical Wnt signaling is a hallmark of colon cancer. The TP53 tumor suppressor gene is altered in many solid tumors, including colorectal cancer, resulting in mutant versions of p53 (mut-p53) that lose their tumor suppressor capacities and acquire new-oncogenic functions (GOFs) critical for disease progression. Although the mechanisms related to mut-p53 GOF have been explored extensively, the relevance of mut-p53 in the canonical Wnt pathway is not well defined. This work investigated the influence of mut-p53 compared to wt-p53 in ß-catenin-dependent Wnt signaling. Using the TCGA public data from Pan-Cancer and the GEPIA2 platform, an in silico analysis of wt-p53 versus mut-p53 genotyped colorectal cancer patients showed that TP53 (p53) and CTNNB1 (ß-catenin) are significantly overexpressed in colorectal cancer, compared with normal tissue. Using p53 overexpression or p53 knockdown assays of wt-p53 or mut-p53, we found that while wt-p53 antagonizes canonical Wnt signaling, mut-p53 induces the opposite effect, improving the ß-catenin-dependent transcriptional activity and colony formation ability of colon cancer cells, which were both decreased by mut-p53 knockdown expression. The mechanism involved in mut-p53-induced activation of canonical Wnt appears to be via AKT-mediated phosphorylation of Ser 552 of ß-catenin, which is known to stabilize and enhance its transcriptional activity. We also found that while wt-p53 expression contributes to 5-FU sensitivity in colon cancer cells, the RITA p53 reactivating molecule counteracted the resistance against 5-FU in cells expressing mut-p53. Our results indicate that mut-p53 GOF acts as a positive regulator of canonical Wnt signaling and participates in the induction of resistance to 5-FU in colon cancer cells.

CD24+CD44+CD54+EpCAM+ gastric cancer stem cells predict tumor progression and metastasis: clinical and experimental evidence.

BACKGROUND: Gastric cancer (GC) is a leading cause of cancer-related deaths worldwide. Specific and thorough identification of cancer cell subsets with higher tumorigenicity and chemoresistance, such as cancer stem cells (CSCs), could lead to the development of new and promising therapeutic targets. For better CSC identification, a complete or extended surface marker phenotype is needed to provide increased specificity for new cell targeting approaches. Our goal is to identify and characterize a putative extended phenotype for CSCs derived from patients with GC before treatment, as well as to evaluate its clinical value. In addition, we aim to ensure that cells with this phenotype have stemness and self-renewal capabilities. METHODS: This is a cohort study including 127 treatment-naïve patients with GC who attended the Instituto Nacional de Cancerología. Multiparametric flow cytometry analysis was performed to determine the extended phenotype of cells derived from gastric biopsies. The tumorigenic capability of cells identified in patients was assessed in a zebrafish model. RESULTS: CD24+CD44+CD54+EpCAM+ cells were present in all treatment-naïve patients included, with a median abundance of 1.16% (0.57-1.89%). The percentage of CD24+CD44+CD54+EpCAM+ cells was categorized as high or low using 1.19% as the cutoff for the CD24+CD44+CD54+EpCAM+ cell subset. Additionally, a higher TNM stage correlated with a higher percentage of CD24+CD44+CD54+EpCAM+ cells (Rho coefficient 0.369; p < 0.0001). We also demonstrated that a higher percentage of CD24+CD44+CD54+EpCAM+ cells was positively associated with metastasis. The metastatic potential of these cells was confirmed in a zebrafish model. Ultimately, under our conditions, we conclude that CD24+CD44+CD54+EpCAM+ cells are true gastric cancer stem cells (GCSCs). CONCLUSION: The CD24+CD44+CD54+EpCAM+ cells present in tissue samples from patients are true GCSCs. This extended phenotype results in better and more specific characterization of these highly tumorigenic cells. The relative quantification of CD24+CD44+CD54+EpCAM+ cells has potential clinical value, as these cells are associated with metastatic disease, making their presence an additional prognostic marker and possibly a target for the design of new antineoplastic treatments in the era of precision oncology. Overall, the extended CD24+CD44+CD54+EpCAM+ phenotype of GCSCs could support their isolation for the study of their stemness mechanisms, leading to the identification of better molecular targets for the development of both new therapeutic approaches such as oncoimmunotherapy and new diagnostic and clinical prognostic strategies for GC.

HPV Prevalence and Predictive Biomarkers for Oropharyngeal Squamous Cell Carcinoma in Mexican Patients.

BACKGROUND: Worldwide prevalence of Oropharyngeal Squamous Cell Carcinoma (OPSCC) has increased, affecting mostly young males. OPSCC associated with Human Papillomavirus (HPV) infection exhibits particular characteristics in terms of response to treatment, hence HPV has been proposed as a prognostic factor. The impact of HPV positivity and associated biomarkers on OPSCC in the Mexican population has not been addressed. Therefore, the analysis of OPSCC prognostic markers in the Mexican population is necessary. METHODS: Retrolective study in Mexican OPSCC patients, where HPV prevalence, p16 and EGFR levels were assessed using INNO-LiPA and immunohistochemistry. RESULTS: We found an HPV prevalence of 57.6% in OPSCC cases treated at a reference center in Mexico. HPV and p16 positivity, as well as EGFR, associate with better outcomes in OPSCC patients, and they also promote reduced death risk. Notably, HPV presence and p16 positivity showed a significant association with disease-free survival (DFS), with a HR of 0.15 (p = 0.006) and a HR of 0.17 (p = 0.012), respectively, indicating a possible role as predictive biomarkers in Mexican OPSCC patients. CONCLUSIONS: Our results reflect the clinical utility of p16 analysis to improve overall survival (OS) and to predict recurrence in oropharyngeal cancer. These results position p16 and HPV as predictive biomarkers for OPSCC.

Association of high-risk human papillomavirus with ocular surface squamous neoplasia: a case-control study in Mexico.

OBJECTIVE: To investigate the association of high-risk hu-man papilloma virus (HR-HPV) and other risk factors with ocular surface squamous cell neoplasia (OSSN). MATERIALS AND METHODS: We obtained DNA from 22 fresh frozen OSSN tissues and 22 pterygia as controls, we used a broad-spectrum HPV DNA amplification short PCR fragment to identify HPV infection in all specimens and then genotyped HPV by a reverse hybridization line probe assay. We also obtained demographic, sun exposure, and tobacco consump-tion information. RESULTS: HR-HPV frequency was 40.9% in the OSSN group and 4.5% in the pterygia group (p=0.009). After covariate adjustment, OSSN was associated with HR-HPV (OR=16.3, 95%CI=1.2,218.1, p=0.03) and sunburn (OR=10.8, 95%CI=1.8,86.0, p=0.02). CONCLUSIONS: Ocular surface squamous cell neoplasia is a multifactorial disease. The strong association between HR-HPV and OSSN, suggests that HR-HPV could play an etiological role in OSSN development.

Association of high-risk human papillomavirus with ocular surface squamous neoplasia: a case-control study in Mexico / Asociación del virus del papiloma humano de alto riesgo con la neoplasia escamosa de la superficie ocular: estudio de casos y controles en México

Abstract: Objective: To investigate the association of high-risk human papilloma virus (HR-HPV) and other risk factors with ocular surface squamous cell neoplasia (OSSN). Materials and methods: We obtained DNA from 22 fresh frozen OSSN tissues and 22 pterygia as controls, we used a broad-spectrum HPV DNA amplification short PCR fragment to identify HPV infection in all specimens and then genotyped HPV by a reverse hybridization line probe assay. We also obtained demographic, sun exposure, and tobacco consumption information. Results: HR-HPV frequency was 40.9% in the OSSN group and 4.5% in the pterygia group (p=0.009). After covariate adjustment, OSSN was associated with HR-HPV (OR=16.3, 95%CI=1.2,218.1, p=0.03) and sunburn (OR=10.8, 95%CI=1.8,86.0, p=0.02). Conclusions: Ocular surface squamous cell neoplasia is a multifactorial disease. The strong association between HR-HPV and OSSN, suggests that HR-HPV could play an etiological role in OSSN development.

Resumen: Objetivo: Investigar la asociación del virus del papiloma humano de alto riesgo (VPH-AR), así como de otros factores, con neoplasia escamosa de la superficie ocular (NESO). Material y métodos: Se obtuvieron 22 especímenes de tejido fresco de NESO y 22 de pterigión como controles; se utilizó una técnica molecular altamente sensible para identificar la infección por VPH en todos los especímenes, así como la genotipificación del VPH. También se obtuvo información demográfica sobre exposición a la luz solar y tabaquismo. Resultados: La frecuencia de infección por VPH-AR fue de 40.9% en el grupo de NESO y de 4.5% en el grupo control (p=0.009). Después de ajustar por covariables, NESO se asoció con el VPH-AR (OR=16.3, IC95%=1.2,218.1, p=0.03) y el eritema solar (OR=10.8, IC95%=1.8,86.0, p=0.02). Conclusiones: La neoplasia escamosa de superficie ocular en una neoplasia multifactorial. Los presentes resultados sugieren que el VPH-AR podría tener un papel etiológico en el desarrollo de NESO.

Quantitative Proteomic Analysis of Cervical Cancer Tissues Identifies Proteins Associated With Cancer Progression.

BACKGROUND/AIM: To date, several proteomics studies in cervical cancer (CC) have focused mainly on squamous cervical cancer (SCC). Our study aimed to discover and clarify differences in SCC and CAD that may provide valuable information for the identification of proteins involved in tumor progression, in CC as a whole, or specific for SCC or CAD. MATERIALS AND METHODS: Total protein extracts from 15 individual samples corresponding to 5 different CC tissue types were compared with a non-cancerous control group using bidimensional liquid chromatography-mass spectrometry (2D LC-MS/MS), isobaric tags for relative and absolute quantitation (ITRAQ), principal component analysis (PCA) and gene set enrichment analysis (GSEA). RESULTS: A total of 622 statistically significant different proteins were detected. Exocytosis-related proteins were the most over-represented, accounting for 25% of the identified and quantified proteins. Based on the experimental results, reticulocalbin 3 (RCN3) and Ras-related protein Rab-14 (RAB14) were chosen for further downstream in vitro and vivo analyses. RCN3 was overexpressed in all CC tissues compared to the control and RAB14 was overexpressed in squamous cervical cancer (SCC) compared to invasive cervical adenocarcinoma (CAD). In the tumor xenograft experiment, RAB14 protein expression was positively correlated with increased tumor size. In addition, RCN3-expressing HeLa cells induced a discrete size increment compared to control, at day 47 after inoculation. CONCLUSION: RAB14 and RCN3 are suggested as potential biomarkers and therapeutic targets in the treatment of CC.

Polyphenols as Antitumor Agents Targeting Key Players in Cancer-Driving Signaling Pathways.

Polyphenols constitute an important group of natural products that are traditionally associated with a wide range of bioactivities. These are usually found in low concentrations in natural products and are now available in nutraceuticals or dietary supplements. A group of polyphenols that include apigenin, quercetin, curcumin, resveratrol, EGCG, and kaempferol have been shown to regulate signaling pathways that are central for cancer development, progression, and metastasis. Here, we describe novel mechanistic insights on the effect of this group of polyphenols on key elements of the signaling pathways impacting cancer. We describe the protein modifications induced by these polyphenols and their effect on the central elements of several signaling pathways including PI3K, Akt, mTOR, RAS, and MAPK and particularly those affecting the tumor suppressor p53 protein. Modifications of p53 induced by these polyphenols regulate p53 gene expression and protein levels and posttranslational modifications such as phosphorylation, acetylation, and ubiquitination that influence stability, subcellular location, activation of new transcriptional targets, and the role of p53 in response to DNA damage, apoptosis control, cell- cycle regulation, senescence, and cell fate. Thus, deep understanding of the effects that polyphenols have on these key players in cancer-driving signaling pathways will certainly lead to better designed targeted therapies, with less toxicity for cancer treatment. The scope of this review centers on the regulation of key elements of cancer signaling pathways by the most studied polyphenols and highlights the importance of a profound understanding of these regulations in order to improve cancer treatment and control with natural products.

High-risk human papillomavirus-18 uses an mRNA sequence to synthesize oncoprotein E6 in tumors.

Cervical cancer is the fourth most common cause of cancer in women worldwide in terms of both incidence and mortality. Persistent infection with high-risk types of human papillomavirus (HPV), namely 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, and 68, constitute a necessary cause for the development of cervical cancer. Viral oncoproteins E6 and E7 play central roles in the carcinogenic process by virtue of their interactions with cell master proteins such as p53, retinoblastoma (Rb), mammalian target of rapamycin (mTOR), and c-MYC. For the synthesis of E6 and E7, HPVs use a bicistronic messenger RNA (mRNA) that has been studied in cultured cells. Here, we report that in cervical tumors, HPV-18, -39, and -45 transcribe E6/E7 mRNAs with extremely short 5' untranslated regions (UTRs) or even lacking a 5' UTR (i.e., zero to three nucleotides long) to express E6. We show that the translation of HPV-18 E6 cistron is regulated by the motif ACCaugGCGCG(C/A)UUU surrounding the AUG start codon, which we term Translation Initiation of Leaderless mRNAs (TILM). This motif is conserved in all HPV types of the phylogenetically coherent group forming genus alpha, species 7, which infect mucosal epithelia. We further show that the translation of HPV-18 E6 largely relies on the cap structure and eIF4E and eIF4AI, two key translation initiation factors linking translation and cancer but does not involve scanning. Our results support the notion that E6 forms the center of the positive oncogenic feedback loop node involving eIF4E, the mTOR cascade, and p53.

Nanog, in Cooperation with AP1, Increases the Expression of E6/E7 Oncogenes from HPV Types 16/18.

Persistent infections with some types of human papillomavirus (HPV) constitute the major etiological factor for cervical cancer development. Nanog, a stem cell transcription factor has been shown to increase during cancer progression. We wanted to determine whether Nanog could modulate transcription of E6 and E7 oncogenes. We used luciferase reporters under the regulation of the long control region (LCR) of HPV types 16 and 18 (HPV16/18) and performed RT-qPCR. We found that Nanog increases activity of both viral regulatory regions and elevates endogenous E6/E7 mRNA levels in cervical cancer-derived cells. We demonstrated by in vitro mutagenesis that changes at Nanog-binding sites found in the HPV18 LCR significantly inhibit transcriptional activation. Chromatin immunoprecipitation (ChIP) assays showed that Nanog binds in vivo to the HPV18 LCR, and its overexpression increases its binding as well as that of c-Jun. Surprisingly, we observed that mutation of AP1-binding sites also affect Nanog's ability to activate transcription, suggesting cooperation between the two factors. We searched for putative Nanog-binding sites in the LCR of several HPVs and surprisingly found them only in those types associated with cancer development. Our study shows, for the first time, a role for Nanog in the regulation of E6/E7 transcription of HPV16/18.

Circulating miR-15b, miR-34a and miR-218 as promising novel early low-invasive biomarkers of cervical carcinogenesis.

Circulating biological markers, such as miRNAs, hold the greatest possibilities to complement tissue biopsy and clinical diagnostic tests. The objective of this study was to evaluate the relative abundance of three circulating miRNAs in serum from 17 HPV16-positive patients with early cervical lesions known as Low-Grade Squamous Intraepithelial Lesions (LSILs). The expression of circulating microRNAs miR-15b, miR-34a and miR-218 in patients with LSILs was compared to 23 HPV-negative individuals showing normal cervical epithelium (healthy women) and 23 Squamous Cell Carcinoma (SCC) samples. The expression levels of miR-15b remained unchanged while those of miRNAs 34a and 218 were relatively high in serum obtained from LSIL patients in comparison with healthy women (results were statistically significant with a p of < 0.01 or < 0.001). According to previous findings, miR-15b was overexpressed and miRNAs 34a and 218 were underexpressed in serum from SCC patients. Additionally, the mRNA expression levels of some selected gene targets were determined [Cyclin D1 (CCND1), Cyclin E1 (CCNE1), B-cell lymphoma 2 (Bcl-2) and MutS homolog 2 (MSH-2)]. All serum results correlated with tissue samples from the same patients. We propose that circulating microRNAs can be valuable as molecular markers for the early follow-up of cervical carcinogenesis risk.

ALDHHIGH Population Is Regulated by the AKT/ß-Catenin Pathway in a Cervical Cancer Model.

ALDH is an enzyme involved in different cellular processes, including cancer. It has been shown that a cellular subpopulation with high ALDH activity (ALDHHIGH) within a tumor is related to functional capabilities such as stemness, chemoresistance, and tumorigenicity. However, few studies have focused on determining the mechanisms behind ALDH activity within the cells. Previously, our group reported that ALDHHIGH cells have higher tumorigenicity in Cervical Cancer (CC) cell lines. Based on this, we were interested to know the molecular mediators of the ALDHHIGH cells, specifically ß-catenin, inasmuch as ß-catenin is regulated through different pathways, such as Wnt signaling, and that it acts as a transcriptional co-activator involved in cancer progression. In this work, we show that the increase in ALDHHIGH cell percentage is reverted by ß-catenin knockdown. Consistently, upon GSK3-ß inactivation, a negative regulator of ß-catenin, we observed an increase in ALDHHIGH cells. Additionally, we observed a low percentage of cells positive for Fzd receptor, suggesting that in our model there is a low capacity to respond to Wnt ligands. The analysis of ALDHHIGH cells in a sphere formation model demonstrated the active state of AKT. In accordance with this, impairment of AKT activity not only reduced ß-catenin active state, but also the percentage of ALDHHIGH cells. This corroborates that AKT acts upstream of ß-catenin, thus affecting the percentage of ALDHHIGH cells. In conclusion, our results show that ALDHHIGH cells are dependent on ß-catenin, in spite of the Wnt pathway seems to be dispensable, while AKT emerges as central player supporting a mechanism in this important axis that is not yet well known but its analysis improves our understanding of ALDH activity on CC.

High prevalence of human papillomavirus type 66 in low-grade cervical lesions of Mexican women.

Our aim was to analyze the prevalence of high-risk human papillomavirus (HR-HPV) and its association with risk factors related to cervical lesions. We used 362 cervical samples from a transversal study to detect nineteen types from the high-risk HPV clade by highly sensitive PCR. Unexpectedly, we found a very high prevalence of HPV type 66 (32.8%), particularly in low-grade squamous intraepithelial lesions. A significant association of HPV66 with previously sexually transmitted disease was observed (p < 0.05). Our results strongly suggest that HPV66 might be indicative of cervical lesions that will not progress to cancer. HPV genotyping by methods that grouped type 66 with other HR-HPV clade types should be interpreted with caution.

CDH1 and SNAI1 are regulated by E7 from human papillomavirus types 16 and 18.

A common characteristic of cancer types associated with viruses is the dysregulated expression of the CDH1 gene, which encodes E­cadherin, in general by activation of DNA methyltransferases (Dnmts). In cervical cancer, E7 protein from high risk human papillomaviruses (HPVs) has been demonstrated to interact with Dnmt1 and histone deacetylase type 1 (HDAC1). The present study proposed that E7 may regulate the expression of CDH1 through two pathways: i) Epigenetic, including DNA methylation; and ii) Epigenetic­independent, including the induction of negative regulators of CDH1 expression, such as Snail family transcriptional repressor Snai1 and Snai2. To test this hypothesis, HPV16­ and HPV18­positive cell lines were used to determine the methylation pattern of the CDH1 promoter and its expression in association with its negative regulators. Different methylation frequencies were identified in the CDH1 promoter in HeLa (88.24%) compared with SiHa (17.65%) and Ca Ski (0%) cell lines. Significant differences in the expression of SNAI1 were observed between these cell lines, and an inverse association was identified between the expression levels of SNAI1 and CDH1. In addition, suppressing E7 not only increased the expression of CDH1, but notably decreased the expression of SNAI1 and modified the methylation pattern of the CDH1 promoter. These results suggested that the expression of CDH1 was dependent on the expression of SNAI1 and was inversely associated with the expression of E7. The present results indicated that E7 from HPV16/18 regulated the expression of CDH1 by the two following pathways in which Snai1 is involved: i) Hypermethylation of the CDH1 promoter region and increasing expression of SNAI1, as observed in HeLa; and ii) Hypomethylation of the CDH1 promoter region and expression of SNAI1, as observed in SiHa. Therefore, the suppression of CDH1 and expression of SNAI1 may be considered to be biomarkers of metastasis in uterine cervical cancer.

High prevalence of human papillomavirus and European variants of HPV 16 infecting concomitantly to cervix and oral cavity in HIV positive women.

OBJECTIVE: Identify the prevalence of HPV infections in the uterine cervix and oral cavity and HPV16 variants in HIV+ women. METHODS: A total of 174 HIV+ women attended an HIV+ specialized clinic in Mexico City. Cells were obtained from the oral cavity and cervix to extract DNA. Polymerase chain reaction (PCR) was used to amplify the HPV sequence with generic primers. We detected specific HPV types using the INNO-LiPA HPV Genotyping Extra II Kit (INNOGENETICS). The identification of variants was studied by sequencing the E6 gene with a Big Dye Terminator Kit and an Applied Biosystems 3500/3500xL genetic analyzer. RESULTS: HPV infection was very high in the uterine cervix (168/174, 96.6%) and oral cavity (161/174, 92.5%). The prevalence of HPV concurrent infections in the cervix and oral cavity was 155/174 (89.1%). We found hrHPVs to be more prevalent than low-risk HPVs (lrHPVs) in the oral cavity (90.2% versus 45.4%) and that infections simultaneously affected the cervix (94.3% versus 36.2%) and oral cavity (85.1% versus 20.1%). Surprisingly, only European variants of HPV type 16 were found in the uterine cervix of women and the oral cavity of all tested samples (52 oral cavity samples and 52 uterine cervix samples). CONCLUSIONS: The high prevalence of HPV, multiple infections and presence of the EP350G intravariant in both anatomical regions are strongly related to the persistence of the virus, which is fundamental for the development of cancer. Therefore, it is very important to control and monitor this high-risk population as well as implement programs for the early detection of HPV and vaccination.

High prevalent human papillomavirus infections of the oral cavity of asymptomatic HIV-positive men.

BACKGROUND: Incidence of anal and oral infections with Human Papillomavirus (HPV) is increasing, particularly among Human Immunodeficiency Virus-positive (HIV+) men. HPV type 16 has exhibited the highest incidence and only limited data is available on other prevalent types, variants of HPV16, as well as associated factors. We were interested in identifying prevalent HPV types, variants of type 16, as well as factors associated with HPV16 infections in the oral cavity of HIV+ men who have sex with men (MSM). METHODS: A cross-sectional study of oral cavity samples from HIV+ MSM, that in a previous study were identified as positive for HPV16 in the anal canal. Cells from the oral cavity (102 samples, paired with 102 from the anal canal of same patient) were used to extract DNA and detect HPV infections using INNO-LiPA HPV Genotyping Extra II, and PCR. From these, 80 samples (paired, 40 anal and 40 oral) were used to identify variants of type 16 by sequencing. Statistical differences were estimated by the X2 test, and p values equal to or less than 0.05 were considered significant. SPSS ver. Twenty-four statistical software (IBM Corp) was used. RESULTS: We found a high prevalence of High-Risk HPV (HR-HPV) and Low-Risk HPV (LR-HPV). Patients were positive in the oral cavity for HR types; 16, 39 and 18 (80.4, 61.8 and 52.9% respectively) and LR types 11 and 6 (53.9 and 34.3% respectively). Surprisingly, only European variants of type 16 were found in the oral cavity, although American Asian (22.5%) and African (2.5%) variants were identified in the anal canal. The analysis showed that CD4 counts could be the most important risk factor associated with HR-HPV infections in the oral cavity, anal canal or both anatomical regions. The risk of infection of the oral cavity with type 18 increased in men diagnosed with HIV for more than 6 years. CONCLUSIONS: Prevalence of both HR and LR HPV's in the oral cavity of Mexican HIV+ MSM is very high. The fact that only European variants of HPV16 were found in the oral cavity suggest a possible tropism not previously described.

Mutant p53 Gain-of-Function: Role in Cancer Development, Progression, and Therapeutic Approaches.

Frequent p53 mutations (mutp53) not only abolish tumor suppressor capacities but confer various gain-of-function (GOF) activities that impacts molecules and pathways now regarded as central for tumor development and progression. Although the complete impact of GOF is still far from being fully understood, the effects on proliferation, migration, metabolic reprogramming, and immune evasion, among others, certainly constitute major driving forces for human tumors harboring them. In this review we discuss major molecular mechanisms driven by mutp53 GOF. We present novel mechanistic insights on their effects over key functional molecules and processes involved in cancer. We analyze new mechanistic insights impacting processes such as immune system evasion, metabolic reprogramming, and stemness. In particular, the increased lipogenic activity through the mevalonate pathway (MVA) and the alteration of metabolic homeostasis due to interactions between mutp53 and AMP-activated protein kinase (AMPK) and Sterol regulatory element-binding protein 1 (SREBP1) that impact anabolic pathways and favor metabolic reprograming. We address, in detail, the impact of mutp53 over metabolic reprogramming and the Warburg effect observed in cancer cells as a consequence, not only of loss-of-function of p53, but rather as an effect of GOF that is crucial for the imbalance between glycolysis and oxidative phosphorylation. Additionally, transcriptional activation of new targets, resulting from interaction of mutp53 with NF-kB, HIF-1α, or SREBP1, are presented and discussed. Finally, we discuss perspectives for targeting molecules and pathways involved in chemo-resistance of tumor cells resulting from mutp53 GOF. We discuss and stress the fact that the status of p53 currently constitutes one of the most relevant criteria to understand the role of autophagy as a survival mechanism in cancer, and propose new therapeutic approaches that could promote the reduction of GOF effects exercised by mutp53 in cancer.

Genes Involved in the Transcriptional Regulation of Pluripotency Are Expressed in Malignant Tumors of the Uterine Cervix and Can Induce Tumorigenic Capacity in a Nontumorigenic Cell Line.

Transcription factors OCT4, SOX2, KLF4, C-MYC, and NANOG (OSKM-N) regulate pluripotency and stemness, and their ectopic expression reprograms human and murine fibroblasts that constitute the key of regenerative medicine. To determine their contribution to cell transformation, we analyzed the gene expression profiles of these transcription factors in cervical cancer samples and found that they are preferentially expressed in the tumor component. Also, cancer stem cell-enriched cultures grown as sphere cultures showed overexpression of OSKM-N genes. Importantly, we observed that lentiviral-mediated transduction of these factors confers, to a nontumorigenic immortalized human cell line, properties of cancer stem cells as the ability to form tumors in a mouse model. When we performed a meta-analysis using microarray data from cervical cancer biopsies and normal tissues, we found that the expression of OSKM-N and some target genes allowed separating tumor and normal tissues between samples, which enhanced the importance of OSKM-N in the tumorigenesis. Finally, we analyzed and compared both transcript and protein expression profiles of these factors within a cohort of patients with cervical cancer. To our knowledge, this is the first time that the expression of OSKM-N is described to induce one of the main characteristics of the cancer stem cell, the tumorigenicity. And, more importantly, its exogenous expression in a nontumorigenic cell line is sufficient to induce a tumorigenic phenotype; furthermore, the differential expression of this transcription factor distinguishes tumor tissue and normal tissue in cervical samples.

Lactate in the Regulation of Tumor Microenvironment and Therapeutic Approaches.

Tumor cells must generate sufficient ATP and biosynthetic precursors in order to maintain cell proliferation requirements. Otto Warburg showed that tumor cells uptake high amounts of glucose producing large volumes of lactate even in the presence of oxygen, this process is known as "Warburg effect or aerobic glycolysis." As a consequence of such amounts of lactate there is an acidification of the extracellular pH in tumor microenvironment, ranging between 6.0 and 6.5. This acidosis favors processes such as metastasis, angiogenesis and more importantly, immunosuppression, which has been associated to a worse clinical prognosis. Thus, lactate should be thought as an important oncometabolite in the metabolic reprogramming of cancer. In this review, we summarized the role of lactate in regulating metabolic microenvironment of cancer and discuss its relevance in the up-regulation of the enzymes lactate dehydrogenase (LDH) and monocarboxilate transporters (MCTs) in tumors. The goal of this review is to expose that lactate is not only a secondary product of cellular metabolic waste of tumor cells, but also a key molecule involved in carcinogenesis as well as in tumor immune evasion. Finally, the possible targeting of lactate production in cancer treatment is discussed.