Late Stages Of Carcinogenesis Research Articles

Common Germline Risk Variants Impact Somatic Alterations and Clinical Features across Cancers.

Meta-analyses across cancers show that common germline risk variants affect not only cancer predisposition but the age of cancer onset and burden of somatic alterations, including total mutations and copy-number alterations.

Short-Term and Long-Term Carcinogenic Effects of Food Contaminants (4-Hydroxynonenal and Pesticides) on Colorectal Human Cells: Involvement of Genotoxic and Non-Genomic Mechanisms.

Simple SummaryOne’s environment, including diet, play a major role in the occurrence and the development of colorectal cancer (CRC). In this study, we are interested in two western diet associated food contaminants: 4-hydroxynonenal (HNE), a major lipid peroxidation product neoformed during digestion, and a mixture of pesticides to which we are commonly exposed to via fruit and vegetable consumption. The aim of this study was to analyse the impact of acute and long-term exposure to these contaminants, alone or in combination, on colorectal carcinogenesis. We used in vitro models of human colonic cells, either exhibiting or not different genetic susceptibilities to CRC. After acute exposure, we did not observe major alteration. However, long-term exposure to contaminants induce malignant transformation with different cellular mechanisms, depending on genetic susceptibility and contaminants alone or in mixtures.To investigate environmental impacts upon colorectal carcinogenesis (CRC) by diet, we assessed two western diet food contaminants: 4-hydroxynonenal (HNE), a major lipid peroxidation product neoformed during digestion, and a mixture of pesticides. We used human colonic cell lines ectopically eliciting varied genetic susceptibilities to CRC: the non-transformed human epithelial colonic cells (HCECs) and their five isogenic cell lines with the loss of APC (Adenomatous polyposis coli) and TP53 (Tumor protein 53) and/or ectopic expression of mutated KRAS (Kristen-ras). These cell lines have been exposed for either for a short time (2–24 h) or for a long period (3 weeks) to 1 µM HNE and/or 10 µM pesticides. After acute exposure, we did not observe any cytotoxicity or major DNA damage. However, long-term exposure to pesticides alone and in mixture with HNE induced clonogenic transformation in normal HCECs, as well as in cells representing later stages of carcinogenesis. It was associated with genotoxic and non-genomic mechanisms (cell growth, metabolic reprogramming, cell mobility and epithelial-mesenchymal transition) depending on genetic susceptibility. This study demonstrated a potential initiating and promoting effect of food contaminants on CRC after long-term exposure. It supports that these contaminants can accelerate carcinogenesis when mutations in oncogenes or tumor suppressor genes occur.

Role of p53 Expression in the Progression of Gastric Cancer in the Indian Population

Introduction: Gastric carcinogenesis frequently affects tumor suppressor TP53 gene, resulting in increased expression of p53 protein and mutations towards later stages of Gastric Carcinoma. Objectives: To analyze p53 protein expression in different stages of gastric cancer to determine if it could be used as a biomarker to allow targeted screening of high risk groups with intestinal metaplasia. Methods: We retrieved 101 formalin fixed paraffin embedded tissue blocks of histopathology proven Gastric Carcinoma specimens and conducted an immunohistochemical study on a subset of 25 cases. Tumor sections were taken with adjacent normal mucosa. p53 expression was evaluated using immunohistochemical markers. With the observations from the study, analysis of p53 expression in different areas of the mucosa was done. Result: Thirteen carcinoma cases (52%) expressed p53 protein with a majority of eight (66.7%) cases showing intensity 3. Normal and metaplastic mucosa did not express p53 protein. In dysplastic mucosa, seven (28%) cases showed p53 expression with intensity ranging from 1 to 3. On comparing the data after excluding the p53 negative regions of normal and metaplastic mucosa, there was no difference with statistical significance. Conclusion: p53 expression is negative in normal and metaplastic gastric mucosa but shows expression in dysplastic and cancer cells. Thus, TP53 mutation is most likely an event towards later stages of carcinogenesis. We are dubious on the ability of p53 to be used as an authentic screening tool at the metaplastic stage to predict progression to carcinoma.

Hypomethylation of LIMD1 and P16 by downregulation of DNMT1 results in restriction of liver carcinogenesis by amarogentin treatment

Amarogentin (active component of Chirata) was found to prevent CCl4/NDEA-induced liver carcinogenesis at mild dysplastic stage through modulation of cell cycle, apoptosis, self-renewal pathways. The cell cycle regulatory genes LIMD1, P16 and RBSP3 were found to be upregulated in restricted liver lesions. To understand the mechanism of upregulation during restriction of cacinogenesis, the effect of amarogentin on epigenetic modification was evaluated in this study. It was also validated in vitro. Hypermethylation of LIMD1 and P16 was seen in mouse hepatocellular carcinoma (30th week carcinogen control mice); however, hypomethylation of these genes was seen in amarogentin-treated liver. In the case of RBSP3, no such change was seen. DNMT1 expression (mRNA/protein) was significantly increased in later stages of carcinogenesis, whereas its expression was comparable to normal liver in the case of amarogentin treatment. No significant change in expression (mRNA/protein) of HDAC1/2 was observed irrespective of treatment. Amarogentin treatment upregulated the expression (mRNA/protein) of LIMD1, P16 and RBSP3 in the HepG2 cell line. Here also treated cells showed LIMD1 and P16 hypomethylation with DNMT1 downregulation. Increased expression of LIMD1, P16 and RBSP3 after treating cells with demethylating agent 5-aza-2-deoxycytidine indicated epigenetic modulation by amarogentin treatment.

Nuclear Factor Erythroid 2-related Factor 2 Knockout Suppresses the Development of Aggressive Colorectal Cancer Formation Induced by Azoxymethane/Dextran Sulfate Sodium-Treatment in Female Mice.

Colon tumors develop more frequently in male than in female. Nuclear factor erythroid 2-related factor 2 (Nrf2) plays differential roles in the stage of tumorigenesis. The purpose of this study was to investigate the role of Nrf2 on colitis-associated tumorigenesis using Nrf2 knockout (KO) female mice. Azoxymethane (AOM) and dextran sulfate sodium (DSS)-treated wild-type (WT) and Nrf2 KO female mice were sacrificed at week 2 and 16 after AOM injection. Severity of colitis, tumor incidence, and levels of inflammatory mediators were evaluated in AOM/DSS-treated WT and Nrf2 KO mice. Furthermore, qRT-PCR, Western blot abnalysis, and ELISA were performed in colon tissues. At week 2, AOM/DSS-induced colon tissue damages were significantly greater in Nrf2 KO than in WT mice. At week 16, tumor numbers (> 2 mm size) were significantly lower in both the proximal and distal colon in Nrf2 KO compared to WT. The overall incidences of adenoma/cancer of the proximal colon and submucosal invasive cancer of the distal colon were reduced by Nrf2 KO. The mRNA and protein expression levels of NF-κB-related mediators (i.e., iNOS and COX-2) and Nrf2-related antioxidants (i.e., heme oxygenase-1 and glutamate-cysteine ligase catalytic subunit) were significantly lower in the Nrf2 KO than in WT mice. Interestingly, the protein level of 15-hydroxyprostaglandin dehydrogenase (15-PGDH) was higher in AOM/DSS-treated Nrf2 KO than in WT mice. Our results support the oncogenic effect of Nrf2 in the later stage of carcinogenesis and upregulation of tumor suppressor 15-PGDH might contribute to the repression of colitis-associated tumorigenesis in Nrf2 KO female mice.

Vitamin B12 may play a preventive role in esophageal precancerous lesions: a case-control study based on markers in blood and 3-day duplicate diet samples.

It is hypothesized that vitamin B12 may prevent tumor initiation during the early stage of carcinogenesis such as esophageal precancerous lesions (EPL), whereas an excessive level may promote tumor progression during the later stages of carcinogenesis. This study aimed to determine the role of vitamin B12 in EPL by detecting vitamin B12-related markers in both blood and diet. This case-control study based on 3-day duplicated diet samples was conducted in a high-risk area of Huai'an, China. A 100 EPL cases and 100 healthy controls matched by gender, age (± 2years) and villages were included. Dietary intake of vitamin B12 and cobalt, plasma cobalt level, the serum levels of vitamin B12 and transcobalamin II (TC II) were quantitatively analyzed. Dietary vitamin B12 intake (p for trend = 0.384) and plasma cobalt level (p for trend = 0.253) were not associated with EPL risk, but high dietary cobalt intake (p for trend = 0.034), increased serum levels of vitamin B12 (p for trend = 0.036) and TC II (p for trend < 0.001) were significantly associated with the reduced EPL risk. However, the significant negative association between dietary cobalt intake, plasma cobalt level or serum vitamin B12 level and EPL was only found in female or male subjects. Excellent transport capability of bio-active vitamin B12 in vivo and adequate levels of vitamin B12 and cobalt may play preventive roles in EPL. Additionally, the association between vitamin B12, cobalt and the risk of EPL may vary in different genders.

The Screening of Antioxidant Activities of Meniran Plants (Phyllanthus niruri Linn) and Guava Leaves (Psidium guajava Linn) Combination Using DPPH Free Radical Method

Degenerative disease is a serious health problem and causes a lot of deaths in Indonesia. One of the most dangerous degenerative diseases is cancer. Free radicals play a role in oxidative stress in the later stages of carcinogenesis. Antioxidant delays or inhibits cellular damage mainly through its free radical scavenging property. Meniran plants and guava leaves have high radical-scavenging activities. The previous studies reported that the combination of ginger and Meniran plant extract has a stronger antioxidant activity than the extract of a single plant. This research aims at determining the antioxidant activities of Meniran plants and guava leaves compared with its singular form. This research was conducted from October to December 2016 at the Chemical Laboratory of Nasional Health Science Institute and the Center for Development and Research of Medicinal Plants and Traditional Medicine, Tawangmangu, Karanganyar. The antioxidant activity assay was done using DPPH free radical method and vitamin C was used as the control. They were measured with UV-Vis Spectrophotometer. This study concludes that the IC50 value of Meniran plants was 30.689 ppm and the IC50 value of guava leaves was 13.7859. The IC50 values of Meniran plant and guava leaf combination with various ratios were 20.6095 ppm (1:1), 12.5629 ppm (1:2), and 16.841 ppm (2:1). The combination of Meniran plant and guava leaf extract (1: 2) had the strongest antioxidant activity of 12.56 ppm.

The PKC universe keeps expanding: From cancer initiation to metastasis.

Classical and novel protein kinase C (PKC) isozymes (c/nPKCs), members of the PKC family that become activated by the lipid second messenger diacylglycerol (DAG) and phorbol esters, exert a myriad of cellular effects that impact proliferative and motile cellular responses. While c/nPKCs have been indisputably associated with tumor promotion, their roles exceed by far their sole involvement as promoter kinases. Indeed, this original dogma has been subsequently redefined by the introduction of several new concepts: the identification of tumor suppressing roles for c/nPKCs, and their participation in early and late stages of carcinogenesis. This review dives deep into the intricate roles of c/nPKCs in cancer initiation as well as in the different stages of the metastatic cascade, with great emphasis in their involvement in cancer cell motility via regulation of small Rho GTPases, the production of extracellular matrix (ECM)-degrading proteases, and the epithelial-to-mesenchymal transition (EMT) program required for the acquisition of highly invasive traits. Here, we highlight functional interplays between either PKCα or PKCε and mesenchymal features that may ultimately contribute to anticancer drug resistance in cellular and animal models. We also introduce the novel hypothesis that c/nPKCs may be implicated in the control of immune evasion through the regulation of immune checkpoint protein expression. In summary, dissecting the colossal complexity of c/nPKC signaling in the wide spectrum of cancer progression may bring new opportunities for the development of meaningful tools aiding for cancer prognosis and therapy.

ANALYSIS OF E-CADHERIN EXPRESSION IN A GROUP OF PRIMARY CUTANEOUS SQUAMOUS CELL CARCINOMAS

E-cadherin is an adhesion molecule essential in maintaining cellular integrity and preserving normal epithelial tissue architecture in adult organisms. Loss of E-cadherin expression and epithelial characteristics has been described in the late stages of carcinogenesis in various human cancers. By loosing cell-cell adhesion mediated by E-cadherin and acquiring mesenchymal properties, a process reffered to as epithelial to mesenchymal transition (EMT), carcinoma cells become more motile and invasive, thus being able to penetrate the surrounding stroma. Our aim is to investigate E-cadherin expression, part of the EMT phenomenom, in cutaneous squamous cell carcinomas (cSCCs), knowing that it represents a valuable model for understanding cancer progression. We conducted a retrospective study, performing immunohistochemical staining of E-cadherin and analyzing its expression in 32 cases of primary cSCCs. E-cadherin membrane positivity was assessed in cells from the main tumor and cells from the invasion front and described in terms of percentage of positive tumoral cells and in terms of intensity. Statistycal analysis showed the proportion of E-Cadherin positive cells in the tumor central and superficial areas is lower in higher degrees of anaplasia (marginally significant p=0.07), confirming the higher potential of poor outcome in these tumors. Median intensity and proportion values of E-Cadherin positive cells were significantly higher in the tumor central and superficial areas than in the invasion front (p&lt;0.0001), suggesting that loss of epithelial features portends higher potential of invasion and metastasis in the setting of EMT. Further studies are required in order to establish clear correlations.

EGFRvIII: An Oncogene with Ambiguous Role.

Epidermal growth factor receptor variant III (EGFRvIII) seems to constitute the perfect therapeutic target for glioblastoma (GB), as it is specifically present on up to 28–30% of GB cells. In case of other tumor types, expression and possible role of this oncogene still remain controversial. In spite of EGFRvIII mechanism of action being crucial for the design of small active anticancer molecules and immunotherapies, i.e., CAR-T technology, it is yet to be precisely defined. EGFRvIII is known to be resistant to degradation, but it is still unclear whether it heterodimerizes with EGF-activated wild-type EGFR (EGFRWT) or homodimerizes (including covalent homodimerization). Constitutive kinase activity of this mutated receptor is relatively low, and some researchers even claim that a nuclear, but not a membrane function, is crucial for its activity. Based on the analyses of recurrent tumors that are often lacking EGFRvIII expression despite its initial presence in corresponding primary foci, this oncogene is suggested to play a marginal role during later stages of carcinogenesis, while even in primary tumors EGFRvIII expression is detected only in a small percentage of tumor cells, undermining the rationality of EGFRvIII-targeting therapies. On the other hand, EGFRvIII-positive cells are resistant to apoptosis, more invasive, and characterized with enhanced proliferation rate. Moreover, expression of this oncogenic receptor was also postulated to be a marker of cancer stem cells. Opinions regarding the role that EGFRvIII plays in tumorigenesis and for tumor aggressiveness are clearly contradictory and, therefore, it is crucial not only to determine its mechanism of action, but also to unambiguously define its role at early and advanced cancer stages.

Expression of Bioactive Chemerin by Keratinocytes Inhibits Late Stages of Tumor Development in a Chemical Model of Skin Carcinogenesis.

Chemerin is a multifunctional protein acting mainly through the G protein-coupled receptor ChemR23/CMKLR1/Chemerin1. Its expression is frequently downregulated in human tumors, including in melanoma and squamous cell carcinoma of the skin and anti-tumoral properties of chemerin were reported in mouse tumor graft models. In the present study, we report the development of spontaneous skin tumors in aged ChemR23-deficient mice. In order to test the potential therapeutic benefit of chemerin analogs, a transgenic model in which bioactive chemerin is over-expressed by basal keratinocytes was generated. These animals are characterized by increased levels of chemerin immunoreactivity and bioactivity in the skin and the circulation. In a chemical carcinogenesis model, papillomas developed later, were less numerous, and their progression to carcinomas was delayed. Temporal control of chemerin expression by doxycycline allowed to attribute its effects to late stages of carcinogenesis. The protective effects of chemerin were partly abrogated by ChemR23 invalidation. These results demonstrate that chemerin is able to delay very significantly tumor progression in a model that recapitulates closely the evolution of solid cancer types in human and suggest that the chemerin-ChemR23 system might constitute an interesting target for therapeutic intervention in the cancer field.

Abstract 5126: Genetic analysis of metachronous pancreatic cancers

Abstract [Introduction] Early detection of pancreatic cancer is a key to curable surgery, although many are diagnosed in advanced stage. However, even in those cases in which cancer was detected early enough for curative resection, metachronous pancreatic cancer may occur in residual pancreas, whose pathogenesis, including its relationship with primary cancer, has been poorly understood. In this study, we aimed to reveal the origin of metachronous pancreatic cancers using an unbiased detection of somatic mutations in primary and metachronous cancers as well as adjacent precursor lesions. [Methods] Samples were obtained from longitudinal sampling from above lesions using laser microdissection from formalin-fixed paraffin-embedded surgical specimens. DNA was extracted and analyzed for somatic mutations of each lesion by whole-exome sequencing with matched normal DNA. On the basis of shared and private mutations across different samples, we interrogated history of clonal evolution of these lesions. [Results] Four patients were enrolled who underwent curative surgery for early pancreatic cancer and subsequently for metachronous tumors in the residual pancreas. Pathology from surgery for primary cancer were margin-negative in all patients. The median interval between the initial and second surgery was 29.8 months (22.8 - 38.3 months). The number of precursor lesions analyzed was from 0 to 5 per patient. The median number of somatic mutations per sample was 78 (range: 41-92) in cancers and 20 (14-42) in precursor lesions. None of the patients have known pathogenic germline mutations. With a median of 78 and 20 mutations per sample, all samples had one or more driver mutations. In each case, all driver mutations that were detected in cancers were shared between primary and metachronous cancer. It indicated that metachronous cancer branched off from primary cancers at later stage of carcinogenesis. And negative margin at initial surgery suggested that metachronous cancer was formed by dissemination or metastasizing rather than Intraductal progression. By contrast, none of the mutations other than a hotspot KRAS mutations were shared between precursor lesions and cancers, suggesting multiple independent clonal growth of precancerous cells in the cancer bearing pancreas. [Conclusions] Our study shows that metachronous pancreatic cancers are derived from the same origin of initial cancer. Therefore, even in the case of early pancreatic cancer careful checkup for recurrence in the residual pancreas is important. Citation Format: Hirano Tomonori, Nobuyuki Kakiuchi, Yasuhide Takeuchi, Yoshikage Inoue, Tomomi Nishimura, Yoichi Fujii, Akira Yokoyama, Hideki Makishima, Toshihiko Masui, Shinji Uemoto, Sachiko Minamiguchi, Hironori Haga, Kenichi Chiba, Hiroko Tanaka, Yuichi Shiraishi, Satoru Miyano, Norimitsu Uza, Yuzo Kodama, Hiroshi Seno, Tsutomu Chiba, Seishi Ogawa. Genetic analysis of metachronous pancreatic cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 5126.

Comparison of oxidative stress on DNA, protein and lipids in patients with actinic keratosis, Bowen's disease and squamous cell carcinoma.

Detailed mechanisms on the effect of oxidative stress (OS), an etiological factor involved in photocarcinogenesis, remain to be fully elucidated. We used immunohistochemical methods to study OS in the DNA, protein and lipids of patients with actinic keratosis (AK), Bowen's disease (BD) and squamous cell carcinoma (SCC). Between January 2009 and December 2014, we treated 230 patients; 79 had AK, 61 had (BD) and 90 had cutaneous SCC; 28 healthy subjects served as the normal controls. OS on DNA, protein and lipids was assessed by the expression of 8-hydroxydeoxyguanosine (8-OHdG), dityrosine (DT) and malondialdehyde (MDA), respectively. 8-OHdG was significantly overexpressed in AK and BD lesions compared with surrounding non-lesional tissue, SCC lesions and the healthy controls. DT was more highly expressed in AK, BD and SCC than in the controls. There was no significant difference among AK, BD and SCC. The expression of MDA was higher in AK, BD and SCC lesions than the controls; SCC showed the highest expression. Our observations suggest that DNA oxidation plays an important role in the early stage of carcinogenesis, that protein oxidation is involved in all stages of carcinogenesis and that lipid oxidation is strongly implicated in the late stages of carcinogenesis.

Sestrin2 Supports Lung Tumor Growth in Early Stages of Cancer Development in Mice but Might Play a Tumor Suppressive Role in the Late Stages of Carcinogenesis

The goal of this study was to understand the role of the p53‐inducible SESN1 and SESN2 genes in the development of lung cancer. Our studies are based on the development of mouse models employing inducible activation of the Kras oncogene in mice deficient for Sesn1 or Sesn2 genes. These mice develop lung cancers in response to injection with Adeno‐Cre virus.The members of the mammalian Sestrin gene family (SESN1, SESN2 and SESN3) encode evolutionary conserved proteins called sestrins that play an important role in regulating cell viability and metabolism in response to stress. The major activity of Sestrins is modulation of mammalian target of rapamycin complexes 1 and 2 (mTORC1/2), which are responsible for regulation of cell growth, metabolism, autophagy and viability. Strikingly, two of three members of the mammalian sestrin family, i.e. SESN1 and SESN2, are targets of transcription factor p53 which plays a major role in tumor suppression. We found that both SESN1 and SESN2 genes are downregulated in the majority of human lung cancers. Therefore, we proposed that SESN1 and SESN2 might be responsible for tumor suppressive activities of p53. However, inactivation of a single Sesn2 gene or both Sesn1 and Sesn2 genes did not affect the number of tumors in mice. Moreover, we observed that Sestrin2‐positive tumors were larger, indicating that Sestrin2 supports tumor growth during early stages of lung carcinogenesis. These effects correlated with higher activity of AKT kinase in the Sestrin2‐proficient mice as compared to Sestrin2‐deficient counterparts. Being a major regulator of cell growth and proliferation, AKT can be a critical target of Sestrin2 in regulating of tumor growth. Nevertheless, we have also demonstrated that silencing of Sestrin2 in human lung adenocarcinoma cells accelerates growth of tumor xenografts in nude mice and provides resistance to anticancer genotoxic drugs.Therefore, we conclude that Sestrin2 support tumor growth at early stages of cancer development, but might suppress carcinogenesis in the late stages. Moreover, tumors with low expression of Sestrin2 may be selected during chemo‐ and radiotherapy.Support or Funding InformationThe studies were supported by the Grant 17‐14‐01420 from the Russian Science Foundation to AB and NCI CA172660 to SG.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Orientin mitigates 1, 2-dimethylhydrazine induced lipid peroxidation, antioxidant and biotransforming bacterial enzyme alterations in experimental rats.

Colorectal cancer (CRC) is the second most diagnosed cancer often identified during the later stages of carcinogenesis. Orientin, a C-glycoside of luteolin, is well known for its versatile therapeutic action toward oxidative stress-induced cellular response may exert chemoprevention against CRC. In our study, we investigated the modulatory effect of orientin on lipid peroxidation, antioxidant defense, and biotransforming bacterial enzymes in 1, 2-dimethylhydrazine (DMH)-induced male albino Wistar rats in a dose-dependent manner. Animals were induced with DMH (20 mg/kg b.wt) for 15 weeks and administered with orientin in three different doses (5 mg/kg, 10 mg/kg, and 20 mg/kg b. wt) daily under distinct phases (initiation, postinitiation, and the entire) for a total treatment period of 30 weeks. Orientin reinstates the alterations induced by DMH on lipid peroxidation and enzymatic antioxidants through its rich-free radical scavenging properties. In addition, orientin curtails the DMH-induced augmentation of biotransforming bacterial enzymes to inhibit the colon cancer progression. Overall, experimental findings suggest that orientin significantly inhibits the DMH induced colon cancer in all the three different doses, however, maximum inhibition was observed on supplementation of 10 mg/kg b.wt for the entire period of the study. Hence, the intraperitoneal administration of 10 mg/kg b.wt orientin for the entire period is recommended for further molecular investigation to elucidate the precise mechanism of inhibition and so orientin can be used as a novel chemotherapeutic agent for CRC.

Emergence of CD26+ Cancer Stem Cells with Metastatic Properties in Colorectal Carcinogenesis

Colorectal cancer results from genetic aberrations which accumulate over a long period of time, with malignant and metastatic properties acquired at a relatively late stage. A subpopulation of CD26+ colorectal cancer stem cells are known to be implicated in metastasis. We quantified CD26+ cancer cells in 11 primary tumor samples by flow cytometry, and showed that tumors having confirmed or suspected metastases harbored a relatively high CD26+ level in these samples. We hypothesized that this subpopulation of cancer stem cells arises in the late stage of carcinogenesis from the bulk of tumor daughter cells which are CD26−. The manipulation of PIK3CA and TP53, two genes commonly deregulated in the late stage, had an effect on the maintenance of the CD26+ cell population. When CD26− tumor daughter cells were sorted and cultured, the emergence of tumor spheres containing CD26+ cells occurred. These findings shed light to the origin of colorectal cancer stem cells with metastatic properties, which has an implication on conventional treatments by surgery or adjuvant chemotherapy for tumor debulking.

Down-Regulation of miRNA-34a, -143 and -212 in the Serum of Patients with Ovarian Cancer

Introduction: Ovarian cancer is one of the most common gynecological malignancy, ranking sixth in frequency and seventh for mortality. Because of the late stage at diagnosis, 5-years survival of patients is remaining below 50% and almost 70% of women present at late stages of carcinogenesis. Expression profile of circulating miRNAs in serum have emerged as potential biomarkers for early detecting various types of diseases including cancer. Present project investigated the expression profile of miRNA-34a, miRNA-143 and miRNA-212 in the serum of 30 ovarian cancer patients and 30 healthy subjects. Materials and Methods: 5 cc of whole blood was collected from each participant and total RNA was extracted using acid guanidinium-phenol-chloroform methods. Expression of targeted miRNAs was evaluated after cDNA synthesis using Real-Time PCR methods. Results: Our results showed expression levels of miRNA-34a (P<0.0001), miRNA-143 (P=0.028) and miRNA-212 (P<0.0001) were significantly decreased in patients with ovarian cancer compare to controls. Data from Receiver Operating Characteristic (ROC) curve analysis has shown that expression profile of these miRNAs could act as potential biomarker for diagnosis of ovarian cancer patients. XRCC3 Thr241Met polymorphism has been associated with cancer susceptibility. Studies have shown a relationship between Thr241Met polymorphism and gastric cancer. The present study was aimed at examining the presence of XRCC3 Thr241Met polymorphism in patients diagnosed with gastric cancer in the city of Macapa. We analyzed 150 DNA samples, of which 100 comprised the control group and 50 were case patients. Our findings revealed that 76% of case samples had the Thr/Met genotype (OR (CI 95% 54.29 (18.84-156.38) p ≤ 0.0001) whereas in the control group, the same genotype represented 7%. Also, most gastric cancer patients with XRCC3 241 Met polymorphism were heterozygotes. Given the small sample size in this study, a larger number of patients will be analyzed.

Expression of ATP6V1C1 during oral carcinogenesis

We investigated the gene and protein expressions of V-type ATPase protein subunit C1 (ATP6V1C1) in cases of oral squamous cell carcinoma (OSCC) and contralateral normal mucosa in smokers, nonsmokers and former smokers. Subjects were separated into five groups of 15: group 1, smokers with OSCC; group 2, normal contralateral mucosa of OSCC patients; group 3, chronic smokers; group 4, former smokers who had stopped smoking 1 year earlier; group 5, individuals who had never smoked. Exfoliative cytology specimens from oral mucosa of smokers, former smokers and nonsmokers showed normal gene and protein expression. We found significantly greater gene expression in the OSCC group than in the nonsmoker groups. No difference in gene expression was observed between normal contralateral mucosa and nonsmoker groups, smoker and nonsmoker groups or former smoker and nonsmoker groups. We observed intense immunostaining for ATP6V1C1 protein in all cases of OSCC and weak or no staining in smoker, former smoker and nonsmoker groups. Significantly greater expression of ATP6V1C1 protein was observed in the OSCC group compared to the other groups, which supports the role of ATP6V1C1 in effecting changes associated with oral cancer. Analysis of the mucosae of chronic smokers, former smokers and the normal contralateral mucosa of patients with OSCC showed unaltered ATP6V1C1 gene and protein expression. Early stages of carcinogenesis, represented by altered epithelium of chronic smokers, had neither gene nor protein alterations as seen in OSCC. Therefore, we infer that the changes in ATP6V1C1 occur during later stages of carcinogenesis. Our preliminary study provides a basis for future studies of using ATP6V1C1 levels for detecting early stage OSCC.

Gene expression profiling signatures for the diagnosis and prevention of oral cavity carcinogenesis-genome-wide analysis using RNA-seq technology.

We compared the changes in global gene expression between an early stage (the termination of the carcinogen treatment and prior to the appearance of frank tumors) and a late stage (frank squamous cell carcinoma (SCC)) of tongue carcinogenesis induced by the carcinogen 4-nitroquinoline 1-oxide (4-NQO) in a mouse model of human oral cavity and esophageal squamous cell carcinoma. Gene ontology and pathway analyses show that increases in "cell cycle progression" and "degradation of basement membrane and ECM pathways" are early events during SCC carcinogenesis and that changes in these pathways are even greater in the actual tumors. Myc, NFκB complex (NFKB1/RELA), and FOS transcription networks are the major transcriptional networks induced in early stage tongue carcinogenesis. Decreases in metabolism pathways, such as in "tricarboxylic acid cycle" and "oxidative phosphorylation", occurred only in the squamous cell carcinomas and not in the early stages of carcinogenesis. We detected increases in ALDH1A3, PTGS2, and KRT1 transcripts in both the early and late stages of carcinogenesis. The identification of the transcripts and pathways that change at an early stage of carcinogenesis provides potentially useful information for early diagnosis and for prevention strategies for human tongue squamous cell carcinomas.

Ionizing radiation, inflammation, and their interactions in colon carcinogenesis in Mlh1-deficient mice.

Genetic, physiological and environmental factors are implicated in colorectal carcinogenesis. Mutations in the mutL homolog 1 (MLH1) gene, one of the DNA mismatch repair genes, are a main cause of hereditary colon cancer syndromes such as Lynch syndrome. Long-term chronic inflammation is also a key risk factor, responsible for colitis-associated colorectal cancer; radiation exposure is also known to increase colorectal cancer risk. Here, we studied the effects of radiation exposure on inflammation-induced colon carcinogenesis in DNA mismatch repair-proficient and repair-deficient mice. Male and female Mlh1−/− and Mlh1+/+ mice were irradiated with 2 Gy X-rays when aged 2 weeks or 7 weeks and/or were treated with 1% dextran sodium sulfate (DSS) in drinking water for 7 days at 10 weeks old to induce mild inflammatory colitis. No colon tumors developed after X-rays and/or DSS treatment in Mlh1+/+ mice. Colon tumors developed after DSS treatment alone in Mlh1−/− mice, and exposure to radiation prior to DSS treatment increased the number of tumors. Histologically, colon tumors in the mice resembled the subtype of well-to-moderately differentiated adenocarcinomas with tumor-infiltrating lymphocytes of human Lynch syndrome. Immunohistochemistry revealed that expression of both p53 and β-catenin and loss of p21 and adenomatosis polyposis coli proteins were observed at the later stages of carcinogenesis, suggesting a course of molecular pathogenesis distinct from typical sporadic or colitis-associated colon cancer in humans. In conclusion, radiation exposure could further increase the risk of colorectal carcinogenesis induced by inflammation under the conditions of Mlh1 deficiency.