Epidemiology and Molecular Biology of HPV Variants in Cervical Cancer: The State of the Art in Mexico

Cervical cancer (CC) continues to be a major public health problem in Mexico, ranking second among cancers in women. A persistent infection with human papillomaviruses (HPV) is the main risk factor for CC development. In addition, a significant fraction of other cancers including those of the anus, oropharynx, and penis are also related to HPV infection. In CC, HPV-16 is the most prevalent high-risk HPV type, followed by HPV-18, both being responsible for 70% of cases. HPV intratype variant lineages differ in nucleotide sequences by 1–10%, while sublineages differ by 0.5–1%. Several studies have postulated that the nucleotide changes that occur between HPV intratype variants are reflected in functional differences and in pathogenicity. Moreover, it has been demonstrated that HPV-16 and -18 intratype variants differentially affect molecular processes in infected cells, changing their biological behavior that finally impacts in the clinical outcome of patients. Mexico has participated in providing knowledge on the geographical distribution of intratype variants of the most prevalent HPVs in premalignant lesions of the cervix and cervical cancer, as well as in other HPV-related tumors. In addition, functional studies have been carried out to assess the cellular effects of intratype variations in HPV proteins. This review addresses the state of the art on the epidemiology of HPV-16 and HPV-18 intratype variants in the Mexican population, as well as their association with persistence, precancer and cervical cancer, and functional aspects related to their biological behavior.     

Modulatory Effects of Polyphenols on Apoptosis Induction: Relevance for Cancer Prevention

Polyphenols, occurring in fruit and vegetables, wine, tea, extra virgin olive oil, chocolate and other cocoa products, have been demonstrated to have clear antioxidant properties in vitro, and many of their biological actions have been attributed to their intrinsic reducing capabilities. However, it has become clear that, in complex biological systems, polyphenols exhibit several additional properties which are yet poorly understood. Apoptosis is a genetically controlled and evolutionarily conserved form of cell death of critical importance for the normal embryonic development and for the maintenance of tissue homeostasis in the adult organism. The malfunction of the death machinery may play a primary role in various pathological processes, since too little or too much apoptosis can lead to proliferative or degenerative diseases, respectively. Cancer cells are characterized by a deregulated proliferation, and/or an inability to undergo programmed cell death. A large body of evidence indicates that polyphenols can exert chemopreventive effects towards different organ specific cancers, affecting the overall process of carcinogenesis by several mechanisms: inhibition of DNA synthesis, modulation of ROS production, regulation of cell cycle arrest, modulation of survival/proliferation pathways. In addition, polyphenols can directly influence different points of the apoptotic process, and/or the expression of regulatory proteins. Although the bulk of data has been obtained in in vitro systems, a number of clinical studies suggesting a preventive and therapeutic effectiveness of polyphenols in vivo is available. However, a deeper knowledge of the underlying mechanisms responsible for the modulation of apoptosis by polyphenols, and their real effectiveness, is necessary in order to propose them as potential chemopreventive and chemotherapeutic candidates for cancer treatment.     

天然抗氧化剂茶多酚的提取工艺

茶叶中一般含有20％－30％的多羟基酚类化合物，茶多酚可用作食品抗氧化剂。常用离子沉淀提取法、树脂吸附分离法、有机溶剂萃取法提取。采用酒石酸铁比色法测定茶多酚含量。     

Phytochemical Targeting of Mitochondria for Breast Cancer Chemoprevention,Therapy, and Sensitization

Breast cancer is a common and deadly disease that causes tremendous physical, emotional, and financial burden on patients and society. Early-stage breast cancer and less aggressive subtypes have promising prognosis for patients, but in aggressive subtypes, and as cancers progress, treatment options and responses diminish, dramatically decreasing survival. Plants are nutritionally rich and biologically diverse organisms containing thousands of metabolites, some of which have chemopreventive, therapeutic, and sensitizing properties, providing a rich source for drug discovery. In this study we review the current landscape of breast cancer with a central focus on the potential role of phytochemicals for treatment, management, and disease prevention. We discuss the relevance of phytochemical targeting of mitochondria for improved anti-breast cancer efficacy. We highlight current applications of phytochemicals and derivative structures that display anti-cancer properties and modulate cancer mitochondria, while describing future applicability and identifying areas of promise.     

Red Wine Polyphenols for Cancer Prevention

Conventional cancer therapies, the second leading cause of death worldwide, result in serious side effects and, at best, merely extend the patient''s lifespan by a few years. Searching for effective prevention is of high priority in both basic and clinical sciences. In recent decades natural products have been considered to be an important source of cancer chemopreventive agents. Red wine polyphenols, which consisted of various powerful antioxidants such as flavonoids and stilbenes, have been implicated in cancer prevention and that promote human health without recognizable side effects. Since resveratrol, a major component of red wine polyphenols, has been studied and reviewed extensively for its chemopreventive activity to interfere with the multi-stage carcinogenesis, this review focuses on recent progress in studies on cancer chemopreventive activities of red wine polyphenol extracts and fractions as well as other red wine polyphenols, like procyanidin B5 analogues and myricetin.     

Alteration of Gene and miRNA Expression in Cervical Intraepithelial Neoplasia and Cervical Cancer

Background: Cervical cancer is one of the most common malignancies in women in terms of prevalence and mortality. Cervical cancer has some particularities that distinguish it from any other oncologic pathology: first, it is completely preventable by prompt detection of its precursor, cervical intraepithelial neoplasia (CIN); second, the Human Papillomavirus (HPV) infection is a known etiological agent; third, the mean age at diagnosis is much lower than in other oncologic conditions, as a consequence of the sexually-transmitted HPV. Methods: We evaluated the expression level of several long noncoding RNAs and a microRNA in samples from 30 patients with CIN, 9 with cervical cancer and 38 normal samples using qRT-PCR technology. Results: We observed higher expression levels for MEG3, DAPK1, MLH1 and MALAT1 in CIN samples than in normal samples, whereas TIMP3 and SOX1 had lower expression levels. For cancer samples, DAPK1, MLH1 and MALAT1 had higher expression, and MEG3, TIMP3 and SOX1 had lower expression when compared to normal samples. In the case of CIN versus cancer samples, only MEG3 gene showed a statistically significant difference. The expression of miR-205-5p was lower in both CIN and cancer samples compared to normal samples. Conclusion: Decreased MEG3 expression could be considered an alarm signal in the transition from a premalignant cervical lesion to invasive cancer, while altered expression levels of TIMP3, SOX1, MLH1, MALAT1 and miR-205-5p could serve as early biomarkers in the diagnosis of premalignant cervical lesions. Future studies, including a larger number of patients with CIN, will be of particular importance in validating these observations.     

Bioprospecting of Natural Compounds from Brazilian Cerrado Biome Plants in Human Cervical Cancer Cell Lines

Cervical cancer is the third most common in Brazilian women. The chemotherapy used for the treatment of this disease can cause many side effects; then, to overcome this problem, new treatment options are necessary. Natural compounds represent one of the most promising sources for the development of new drugs. In this study, 13 different species of 6 families from the Brazilian Cerrado vegetation biome were screened against human cervical cancer cell lines (CCC). Some of these species were also evaluated in one normal keratinocyte cell line (HaCaT). The effect of crude extracts on cell viability was evaluated by a colorimetric method (MTS assay). Extracts from Annona crassiflora, Miconia albicans, Miconia chamissois, Stryphnodendron adstringens, Tapirira guianensis, Xylopia aromatica, and Achyrocline alata showed half-maximal inhibitory concentration (IC₅₀) values < 30 μg/mL for at least one CCC. A. crassiflora and S. adstringens extracts were selective for CCC. Mass spectrometry (Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometer (ESI FT-ICR MS)) of A. crassiflora identified fatty acids and flavonols as secondary compounds. One of the A. crassiflora fractions, 7C24 (from chloroform partition), increased H2AX phosphorylation (suggesting DNA damage), PARP cleavage, and cell cycle arrest in CCC. Kaempferol-3-O-rhamnoside and oleic acid were bioactive molecules identified in 7C24 fraction. These findings emphasize the importance of investigating bioactive molecules from natural sources for developing new anti-cancer drugs.     

Analysis of HPV Integrations in Mexican Pre-Tumoral Cervical Lesions Reveal Centromere-Enriched Breakpoints and Abundant Unspecific HPV Regions

Human papillomavirus (HPV) DNA integration is a crucial event in cervical carcinogenesis. However, scarce studies have focused on studying HPV integration (HPVint) in early-stage cervical lesions. Using HPV capture followed by sequencing, we investigated HPVint in pre-tumor cervical lesions. Employing a novel pipeline, we analyzed reads containing direct evidence of the integration breakpoint. We observed multiple HPV infections in most of the samples (92%) with a median integration rate of 0.06% relative to HPV mapped reads corresponding to two or more sequence breakages. Unlike cancer studies, most integrations events were unique (supported by one read), consistent with the lack of clonal selection. Congruent to other studies, we found that breakpoints could occur, practically, in any part of the viral genome. We noted that L1 had a higher frequency of rupture integration (25%). Based on host genome integration frequencies, we found previously reported integration sites in cancer for genes like FHIT, CSMD1, and LRP1B and putatively many new ones such as those exemplified in CSMD3, ROBO2, and SETD3. Similar host integrations regions and genes were observed in diverse HPV types within many genes and even equivalent integration positions in different samples and HPV types. Interestingly, we noted an enrichment of integrations in most centromeres, suggesting a possible mechanism where HPV exploits this structural machinery to facilitate integration. Supported by previous findings, overall, our analysis provides novel information and insights about HPVint.     

P16 and HPV Genotype Significance in HPV-Associated Cervical Cancer—A Large Cohort of Two Tertiary Referral Centers

The expression of p16 is a good surrogate of human papillomavirus (HPV) infection in HPV-associated cancers. The significance of p16 expression, HPV genotype and genera in the outcome of patients with HPV-associated cervical cancer (CC) is unclear. Our aim is to ascertain the prognostic significance of these factors. Data from 348 patients (median age: 47.5 years old) with CC, diagnosed in two referral centers, were retrospectively collected. Advanced disease (FIGO2018 IB2-IV) was present in 68% of patients. A single HPV genotype was identified in 82.8% of patients. The most common HPVs were HPV16 (69%) and HPV18 (14%). HPV genera reflected this distribution. HPV16 tumors presented at an earlier stage. P16 was negative in 18 cases (5.2%), 83.3% of which were squamous cell carcinomas. These cases occurred in older patients who tended to have advanced disease. In the univariate analysis, HPV16 (HR: 0.58; p = 0.0198), α-9 genera (HR: 0.37; p = 0.0106) and p16 overexpression (HR: 0.54; p = 0.032) were associated with better survival. HPV16 (HR: 0.63; p = 0.0174) and α-9 genera (HR: 0.57; p = 0.0286) were associated with less relapse. In the multivariate analysis, only the International Federation of Gynecology and Obstetrics (FIGO) stage retained an independent prognostic value. HPV16, α-9 genera and p16 overexpression were associated with better survival, although not as independent prognostic factors. Patients with p16-negative HPV-associated CC were older, presented with advanced disease and had worse prognosis.     

Dietary Polyphenols in Prevention and Treatment of Prostate Cancer

Prostate cancer is the most prevalent disease affecting males in many Western countries, with an estimated 29,480 deaths in 2014 in the US alone. Incidence rates for prostate cancer deaths have been decreasing since the early 1990s in men of all races/ethnicities, though they remain about 60% higher in African Americans than in any other group. The relationship between dietary polyphenols and the prevention of prostate cancer has been examined previously. Although results are sometimes inconsistent and variable, there is a general agreement that polyphenols hold great promise for the future management of prostate cancer. Various dietary components, including polyphenols, have been shown to possess anti-cancer properties. Generally considered as non-toxic, dietary polyphenols act as key modulators of signaling pathways and are therefore considered ideal chemopreventive agents. Besides possessing various anti-tumor properties, dietary polyphenols also contribute to epigenetic changes associated with the fate of cancer cells and have emerged as potential drugs for therapeutic intervention. Polyphenols have also been shown to affect post-translational modifications and microRNA expressions. This article provides a systematic review of the health benefits of selected dietary polyphenols in prostate cancer, especially focusing on the subclasses of polyphenols, which have a great effect on disease prevention and treatment.     

Plant Polyphenols as Chemopreventive Agents for Lung Cancer

Lung cancer may be prevented by a diet rich in fruits and vegetables as they are enriched with dietary antioxidant polyphenols, such as flavonoids, proanthocyanidins, lignans, stilbenes, and phenolic acids. Dietary polyphenols exert a wide range of beneficial biological functions beyond their antioxidative properties and are involved in regulation of cell survival pathways leading to anticarcinogenic and antimutagenic functions. There are sufficient evidence from in vitro, in vivo, and epidemiological studies to suggest that the dietary intervention of polyphenols in cancer prevention, including the chemopreventive ability of dietary polyphenols, act against lung carcinogens. Cohort and epidemiological studies in selected risk populations have evaluated clinical effects of polyphenols. Polyphenols have demonstrated three major actions: antioxidative activity, regulation of phase I and II enzymes, and regulation of cell survival pathways against lung carcinogenesis. They have also shown an inverse association of lung cancer occurrences among high risk populations who consumed considerable amounts of fruits and vegetables in their daily diet. In in vitro cell culture experimental models, polyphenols bind with electrophilic metabolites from carcinogens, inactivate cellular oxygen radicals, prevent membrane lipid peroxidation and DNA oxidative damage, and adduct formation. Further, polyphenols enhance the detoxifying enzymes such as the phase II enzymes, glutathione transferases and glucuronosyl transferases.     

The Dysregulation of MicroRNAs in the Development of Cervical Pre-Cancer—An Update

Globally in 2020, an estimated ~600,000 women were diagnosed with and 340,000 women died from cervical cancer. Compared to 2012, the number of cases increased by 7.5% and the number of deaths increased by 17%. MiRNAs are involved in multiple processes in the pathogenesis of cervical cancer. Dysregulation of miRNAs in the pre-stage of cervical cancer is the focus of this review. Here we summarize the dysregulated miRNAs in clinical samples from cervical pre-cancer patients and relate them to the early transformation process owing to human papillomavirus (HPV) infection in the cervical cells. When HPV infects the normal cervical cells, the DNA damage response is initiated with the involvement of HPV’s E1 and E2 proteins. Later, cell proliferation and cell death are affected by the E6 and E7 proteins. We find that the expressions of miRNAs in cervical pre-cancerous tissue revealed by different studies seldom agreed with each other. The discrepancy in sample types, samples’ HPV status, expression measurement, and methods for analysis contributed to the non-aligned results across studies. However, several miRNAs (miR-34a, miR-9, miR-21, miR-145, and miR-375) were found to be dysregulated across multiple studies. In addition, there are hints that the DNA damage response and cell growth response induced by HPV during the early transformation of the cervical cells are related to these miRNAs. Currently, no review articles analyse the relationship between the dysregulated miRNAs in cervical pre-cancerous tissue and their possible roles in the early processes involving HPV’s protein encoded by the early genes and DNA damage response during normal cell transformation. Our review provides insight on spotting miRNAs involved in the early pathogenic processes and pointing out their potential as biomarker targets of cervical pre-cancer.     

分光光度法测定天然多酚类化合物含量的研究进展

介绍了近年来分光光度法在测定天然多酚类化合物方面的研究进展。综述了测定天然多酚类化合物方法的应用范围,对测定方法按化学反应进行分类,如络合反应、氧化还原反应、亲核加成反应和重氮化-偶合反应等,并探讨了测定方法的反应原理及测定方法中存在的问题,对今后的研究方向作了展望。     

Natural Polyphenols as Modulators of Etoposide Anti-Cancer Activity

Polyphenols are naturally occurring compounds found in abundance in fruits and vegetables. Their health-promoting properties and their use in the prevention and treatment of many human diseases, including cancer, have been known for years. Many anti-cancer drugs are derived from these natural compounds. Etoposide, which is a semi-synthetic derivative of podophyllotoxin, a non-alkaloid lignan isolated from the dried roots and rhizomes of Podophyllum peltatum or Podophyllum emodi (Berberidaceae), is an example of such a compound. In this review, we present data on the effects of polyphenols on the anti-cancer activity of etoposide in in vitro and in vivo studies.     

Potential Antioxidant and Anti-Inflammatory Function of Gynura procumbens Polyphenols Ligand

The antioxidant and anti-inflammatory potentials of polyphenols contained in Gynura procumbens (GP) extract were systematically analyzed. Polyphenols in GP were analyzed for nine peaks using high-performance liquid chromatography (HPLC) combined with mass spectrometry (MS), and quantitatively determined through each standard. A total of nine polyphenolic compounds were identified in the samples and their MS data were tabulated. To determine the potential of bioactive ingredients targeting DPPH and COX-2, we analyzed them by ultrafiltration combined with LC. The results identified the major compounds exhibiting binding affinity for DPPH and COX-2. Caffeic acid, kynurenic acid, and chlorogenic acid showed excellent binding affinity to DPPH and COX-2, suggesting that they can be considered as major active compounds. Additionally, the anti-inflammatory effect of GP was confirmed in vitro. This study will not only be used to provide basic data for the application of GP to the food and pharmaceutical industries, but will also provide information on effective screening methods for other medicinal plants.     

Multistep Model of Cervical Cancer: Participation of miRNAs and Coding Genes

Aberrant miRNA expression is well recognized as an important step in the development of cancer. Close to 70 microRNAs (miRNAs) have been implicated in cervical cancer up to now, nevertheless it is unknown if aberrant miRNA expression causes the onset of cervical cancer. One of the best ways to address this issue is through a multistep model of carcinogenesis. In the progression of cervical cancer there are three well-established steps to reach cancer that we used in the model proposed here. The first step of the model comprises the gene changes that occur in normal cells to be transformed into immortal cells (CIN 1), the second comprises immortal cell changes to tumorigenic cells (CIN 2), the third step includes cell changes to increase tumorigenic capacity (CIN 3), and the final step covers tumorigenic changes to carcinogenic cells. Altered miRNAs and their target genes are located in each one of the four steps of the multistep model of carcinogenesis. miRNA expression has shown discrepancies in different works; therefore, in this model we include miRNAs recording similar results in at least two studies. The present model is a useful insight into studying potential prognostic, diagnostic, and therapeutic miRNAs.     

Trichostatin A Enhances the Apoptotic Potential of Palladium Nanoparticles in Human Cervical Cancer Cells

Cervical cancer ranks seventh overall among all types of cancer in women. Although several treatments, including radiation, surgery and chemotherapy, are available to eradicate or reduce the size of cancer, many cancers eventually relapse. Thus, it is essential to identify possible alternative therapeutic approaches for cancer. We sought to identify alternative and effective therapeutic approaches, by first synthesizing palladium nanoparticles (PdNPs), using a novel biomolecule called saponin. The synthesized PdNPs were characterized by several analytical techniques. They were significantly spherical in shape, with an average size of 5 nm. Recently, PdNPs gained much interest in various therapies of cancer cells. Similarly, histone deacetylase inhibitors are known to play a vital role in anti-proliferative activity, gene expression, cell cycle arrest, differentiation and apoptosis in various cancer cells. Therefore, we selected trichostatin A (TSA) and PdNPs and studied their combined effect on apoptosis in cervical cancer cells. Cells treated with either TSA or PdNPs showed a dose-dependent effect on cell viability. The combinatorial effect, tested with 50 nM TSA and 50 nMPdNPs, had a more dramatic inhibitory effect on cell viability, than either TSA or PdNPs alone. The combination of TSA and PdNPs had a more pronounced effect on cytotoxicity, oxidative stress, mitochondrial membrane potential (MMP), caspase-3/9 activity and expression of pro- and anti-apoptotic genes. Our data show a strong synergistic interaction between TSA and PdNPs in cervical cancer cells. The combinatorial treatment increased the therapeutic potential and demonstrated relevant targeted therapy for cervical cancer. Furthermore, we provide the first evidence for the combinatory effect and cytotoxicity mechanism of TSA and PdNPs in cervical cancer cells.