Aflatoxin-induced TP53 R249S mutation in hepatocellular carcinoma in Thailand: association with tumors developing in the absence of liver cirrhosis

p53 Mutation at Serine 249 and Its Gain of Function Are Highly Related to Hepatocellular Carcinoma after Smoking Exposure

BACKGROUND

It has been convincingly suggested that a close correlation exists between the incidence of hepatocellular carcinoma (HCC) and cigarette smoking. However, the underlying effect of smoking on HCC is not clear.

METHODS

A binary unconditional logistic regression was used for the data on a total of 300 cases and 612 controls. The approach of functional analysis of separated alleles in yeast and direct sequencing of TP53 mutations were applied to analyze the p53 status in the HCC group. The relationship between p53 mutation at serine 249 (p53-RS) and smoking was assessed. Quantitative reverse transcription PCR was employed for the evaluation to transcriptional activity of p53 and p53-RS.

RESULTS

Smoking was linked to the risk of HCC with an increased dose-response effect. Moreover, among subjects who did not drink, the risks of HCC were significantly increased for smokers between HCC and controls. Besides, there was an increase in the number of HCC in smokers compared to nonsmokers after exclusion of HBV and/or HCV infection. Also, a significant difference was observed in the incidence of p53-RS between smokers and nonsmokers the HCC group. Furthermore, the p53-RS transcriptional activity was significantly increased in tumor tissues.

CONCLUSIONS

It strongly demonstrated that tobacco smoking is positively and independently associated with HCC, which may be attributed to p53-RS and its gain of function.

Chemical Risk Factors of Primary Liver Cancer: An Update

Primary liver cancer has the sixth highest incidence and fourth highest cancer mortality worldwide. Hepatitis B is the leading cause of liver cancer, though its incidence is decreasing with vaccination. Alcohol is the leading cause of liver transplant, cirrhosis, and cancer in the developed world, and is projected to surpass hepatitis B as the leading hepatic cancer etiology worldwide. Tobacco smoking has shown a positive association with liver cancer in a majority of studies, though not all. Aflatoxin, a mycotoxin produced by Aspergillus, is estimated to account for 3–20% of global liver cancer cases, 40% of which occur in sub-Saharan Africa. These statistics are confounded by the prevalence of hepatitis B, which may have a synergistic effect on hepatic carcinogenesis. Aflatoxin is ingested and likely inhaled from agricultural products, placing farmers, food processors, and textile workers in developing nations at risk. Vinyl-chloride is used in the production of PVC plastics and causes rare liver angiosarcoma, hepatocellular carcinoma, and other neoplasms. Arsenic and cadmium are naturally-occurring, hepatocarcinogenic metals with high occupational exposure in industries involving coal, metals, plastics, and batteries. Millions of laborers in waste-disposal and manufacturing are exposed to organic solvents and N-nitrosamines, which vary from carcinogenic (group 1) to possibly carcinogenic (group 2B) in their IARC designation. Insecticide DDT is possibly hepatocarcinogenic (group 2B), though continues to be used for malaria control in the developing world. While suggested by case reports, anabolic steroids and oral contraceptives have not been shown to increase liver cancer risk in large studies.

Toward Cancer Diagnostics of the Tumor Suppressor p53 by Surface Enhanced Raman Spectroscopy

The tumor suppressor p53 protein plays a crucial role in many biological processes. The presence of abnormal concentrations of wild-type p53, or some of its mutants, can be indicative of a pathological cancer state. p53 represents therefore a valuable biomarker for tumor screening approaches and development of suitable biosensors for its detection deserves a high interest in early diagnostics. Here, we revisit our experimental approaches, combining Surface Enhanced Raman Spectroscopy (SERS) and nanotechnological materials, for ultrasensitive detection of wild-type and mutated p53, in the perspective to develop biosensors to be used in clinical diagnostics. The Raman marker is provided by a small molecule (4-ATP) acting as a bridge between gold nanoparticles (NPs) and a protein biomolecule. The Azurin copper protein and specific antibodies of p53 were used as a capture element for p53 (wild-type and its mutants). The developed approaches allowed us to reach a detection level of p53 down to 10^-17 M in both buffer and serum. The implementation of the method in a biosensor device, together with some possible developments are discussed.

Hepatocellular carcinoma: old friends and new tricks

Hepatocellular carcinoma (HCC) is the most prevalent primary liver cancer and a leading cause of cancer-related deaths worldwide. Ninety percent of HCC cases arise from cirrhosis, during which liver cells undergo chronic cycles of necrosis and regeneration. The complex genomic landscape of HCC has been extensively investigated to draw correlations between recurrently mutated pathways and patient prognosis. However, our limited success with targeted therapy shows that knowing the presence of somatic mutations alone is insufficient for us to gauge the full spectrum of their functional consequences in the context of tumor evolution. In addition, the current molecular classification of HCC offers little information on the relationship between the molecular features and immunological properties of HCC tumors and their immune microenvironment. This review introduces current challenges and advancements made in HCC surveillance, diagnosis, and treatment. We also discuss the suite of HCC-associated genetic changes and describe recent studies that provide evidence for an evolving functional model and its implications for understanding and targeting HCC progression.

The Effect of a Newly Synthesized Ferrocene Derivative against MCF-7 Breast Cancer Cells and Spheroid Stem Cells through ROS Production and Inhibition of JAK2/STAT3 Signaling Pathway

Background:

Breast Cancer Stem Cells (BCSCs) possess the ability of self-renewal and cellular heterogeneity, and therefore, play a key role in the initiation, propagation and clinical outcome of breast cancer. It has been shown that ferrocene complexes have remarkable potential as anticancer drugs.

Objective:

The present study was conducted to investigate the effects of a novel ferrocene complex, 1- ferrocenyl-3-(4-methylsulfonylphenyl)propen-1-one (FMSP) on MCF-7 breast cancer cell line and its derived mammospheres with cancer stem cell properties.

Methods:

Mammospheres were developed from MCF-7 cells and validated by the evaluation of CD44 and CD24 cell surface markers by flow cytometry as well as of the expression of genes that are associated with stem cell properties by real-time PCR. Cells viability was assessed by a soluble tetrazolium salt (MTS) after the treatment of cells with various concentrations of FMSP. Apoptosis was evaluated by flow cytometry analysis of annexin V and PI labeling of cells. Reactive Oxygen Species (ROS) production was measured using a cellpermeable, oxidant-sensitive fluorescence probe (carboxy-H2DCFDA). The involvement of the JAK2/STAT3 pathway was also investigated by western blotting.

Results:

FMSP could successfully prevent mammosphere formation from differentiated MCF-7 cells and significantly down-regulated the expression of genes involved in the production of the stem cell properties including Wnt1, Notch1, β -catenin, SOX2, CXCR4 and ALDH1A1. FMSP decreased cell viability in both MCF-7 cells and spheroid cells, although MCF-10A cells were unaffected by this compound. Apoptosis was also dramatically induced by FMSP, via ROS production but independent of CD95 activation. Phosphorylation levels of JAK2 and STAT3 were also found to be significantly attenuated even in the presence of IL-6, the putative activator of the JAK/STAT pathway.

Conclusion:

FMSP can effectively target BCSCs via ROS production and modulation of major signaling pathways that contribute to the stemness of breast cancer cells, and therefore, might be considered a promising anticancer agent after in vivo studies.

Wild type p53 function in p53Y220C mutant harboring cells by treatment with Ashwagandha derived anticancer withanolides: bioinformatics and experimental evidence

Background

Tumor suppressor p53 protein is frequently mutated in a large majority of cancers. These mutations induce local or global changes in protein structure thereby affecting its binding to DNA. The structural differences between the wild type and mutant p53 thus provide an opportunity to selectively target mutated p53 harboring cancer cells. Restoration of wild type p53 activity in mutants using small molecules that can revert the structural changes have been considered for cancer therapeutics.

Methods

We used bioinformatics and molecular docking tools to investigate the structural changes between the wild type and mutant p53 proteins (p53^V143A, p53^R249S, p53^R273H and p53^Y220C) and explored the therapeutic potential of Withaferin A and Withanone for restoration of wild type p53 function in cancer cells. Cancer cells harboring the specific mutant p53 proteins were used for molecular assays to determine the mutant or wild type p53 functions.

Results

We found that p53^V143A mutation does not show any significant structural changes and was also refractory to the binding of withanolides. p53^R249S mutation critically disturbed the H-bond network and destabilized the DNA binding site. However, withanolides did not show any selective binding to either this mutant or other similar variants. p53^Y220C mutation created a cavity near the site of mutation with local loss of hydrophobicity and water network, leading to functionally inactive conformation. Mutated structure could accommodate withanolides suggesting their conformational selectivity to target p53^Y220C mutant. Using human cell lines containing specific p53 mutant proteins, we demonstrated that Withaferin A, Withanone and the extract rich in these withanolides caused restoration of wild type p53 function in mutant p53^Y220C cells. This was associated with induction of p21^WAF-1-mediated growth arrest/apoptosis.

Conclusion

The study suggested that withanolides may serve as highly potent anticancer compounds for treatment of cancers harboring a p53^Y220C mutation.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1099-x) contains supplementary material, which is available to authorized users.

Liquid biopsies for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the world's second leading cause of cancer death; 82.4% of patients die within 5 years. This grim prognosis is the consequence of a lack of effective early detection tools, limited treatment options, and the high frequency of HCC recurrence. Advances in the field of liquid biopsy hold great promise in improving early detection of HCC, advancing patient prognosis, and ultimately increasing the survival rate. In an effort to address the current challenges of HCC screening and management, several studies have identified and evaluated liver-cancer-associated molecular signatures such as genetic alterations, methylation, and noncoding RNA expression in the form of circulating biomarkers in body fluids and circulating tumor cells of HCC patients. In this review, we summarize the recent progress in HCC liquid biopsy, organized by the intended clinical application of the reported study.

Genetic polymorphisms in ataxin-3 and liver cirrhosis risk related to aflatoxin B1

BACKGROUND

Altered expression of ataxin-3 (AT3) can modify DNA repair capacity and is observed in human diseases. The genetic polymorphisms of this gene in aflatoxin B1 (AFB1)-related liver cirrhosis (LC) have not yet been elucidated.

MATERIALS AND METHODS

We conducted a hospital-based case-control study, including 384 patients with LC and 851 controls without any liver diseases, to assess the association between 264 polymorphisms in AT3 and AFB1-related LC risk. Genotype were tested using TaqMan-PCR or sequencing technique.

RESULTS

We found three differentially distributed SNPs (rs8021276, rs7158733, and rs10146249) via the screening analysis; however, only rs8021276 polymorphism was further identified to modify the risk of LC. Compared with the homozygote of rs8021276 A alleles (rs8021276-AA), the genotypes of rs8021276 G alleles (rs8021276-AG or -GG) increased LC risk (OR: 2.48 and 6.98; 95% CI: 1.84-3.33 and 4.35-11.22, respectively). Significant interactive effects between risk genotypes and AFB1 exposure status were also observed in the joint effects analysis. Additionally, rs8021276 polymorphism was also associated with down-regulation of AT3 mRNA expression and increasing AFB1-DNA adducts in liver tissues with cirrhosis.

CONCLUSIONS

These results suggest AT3 polymorphisms may be risk biomarkers of AFB1-related LC, and rs8021276 is a potential candidate.

Somatic mutation driven codon transition bias in human cancer

Accumulation of DNA mutations alters amino acid sequence in the key domains of oncoproteins, leading to cellular malignant transformation. Due to redundancy of the genetic code, the same amino acid alteration can be achieved by multiple distinct genetic mutations, which are considered functionally identical and not actively distinguished in the current cancer genome research. For the first time, we analyzed the distribution of codon level transitions acquired by somatic mutations in human cancers. By analyzing the ~2.5 million nonsynonymous somatic single nucleotide variations (SNVs) found in the COSMIC database, we found 41 recurrent amino acid alterations whose DNA changes are significantly biased toward a specific codon transition. Additional analyses partially identified functional discrepancies between the favored and avoided codon transitions in terms of mutational process, codon usage, alternative splicing, and mRNA stability.

Association of Aflatoxin and Gallbladder Cancer

BACKGROUND & AIMS

Aflatoxin, which causes hepatocellular carcinoma, may also cause gallbladder cancer. We investigated whether patients with gallbladder cancer have higher exposure to aflatoxin than patients with gallstones.

METHODS

We measured aflatoxin B1 (AFB1)-lysine adducts in plasma samples from the Shanghai Biliary Tract Cancer case-control study, conducted from 1997 through 2001. We calculated age- and sex-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) and the population-attributable fraction for 209 patients with gallbladder cancer and gallstones vs 250 patients with gallstones without cancer (controls). In 54 patients with gallbladder cancer, tumor tissue was examined for the R249S mutation in TP53, associated with aflatoxin exposure, through targeted sequencing.

RESULTS

The AFB1-lysine adduct was detected in 67 (32%) of 209 patients with gallbladder cancer and 37 (15%) of the 250 controls (χ2 P < .0001), almost threefold more patients with gallbladder cancer than controls (OR, 2.71; 95% CI, 1.70-4.33). Among participants with detectable levels of AFB1-lysine, the median level of AFB1-lysine was 5.4 pg/mg in those with gallbladder cancer, compared with 1.2 pg/mg in controls. For patients in the fourth quartile of AFB1-lysine level vs the first quartile, the OR for gallbladder cancer was 7.61 (95% CI, 2.01-28.84). None of the 54 gallbladder tumors sequenced were found to have the R249S mutation in TP53. The population-attributable fraction for cancer related to aflatoxin was 20% (95% CI, 15%-25%).

CONCLUSIONS

In a case-control study of patients with gallbladder cancer and gallstones vs patients with gallstones without cancer, we associated exposure to aflatoxin (based on plasma level of AFB1-lysine) with gallbladder cancer. Gallbladder cancer does not appear associate with the R249S mutation in TP53. If aflatoxin is a cause of gallbladder cancer, it may have accounted for up to 20% of the gallbladder cancers in Shanghai, China, during the study period, and could account for an even higher proportion in high-risk areas. If our findings are verified, reducing aflatoxin exposure might reduce the incidence of gallbladder cancer.

Mutational spectra of aflatoxin B1 in vivo establish biomarkers of exposure for human hepatocellular carcinoma

Aflatoxin B₁ (AFB₁) and/or hepatitis B and C viruses are risk factors for human hepatocellular carcinoma (HCC). Available evidence supports the interpretation that formation of AFB₁-DNA adducts in hepatocytes seeds a population of mutations, mainly G:C→T:A, and viral processes synergize to accelerate tumorigenesis, perhaps via inflammation. Responding to a need for early-onset evidence predicting disease development, highly accurate duplex sequencing was used to monitor acquisition of high-resolution mutational spectra (HRMS) during the process of hepatocarcinogenesis. Four-day-old male mice were treated with AFB₁ using a regimen that induced HCC within 72 wk. For analysis, livers were separated into tumor and adjacent cellular fractions. HRMS of cells surrounding the tumors revealed predominantly G:C→T:A mutations characteristic of AFB₁ exposure. Importantly, 25% of all mutations were G→T in one trinucleotide context (CGC; the underlined G is the position of the mutation), which is also a hotspot mutation in human liver tumors whose incidence correlates with AFB₁ exposure. The technology proved sufficiently sensitive that the same distinctive spectrum was detected as early as 10 wk after dosing, well before evidence of neoplasia. Additionally, analysis of tumor tissue revealed a more complex pattern than observed in surrounding hepatocytes; tumor HRMS were a composite of the 10-wk spectrum and a more heterogeneous set of mutations that emerged during tumor outgrowth. We propose that the 10-wk HRMS reflects a short-term mutational response to AFB₁, and, as such, is an early detection metric for AFB₁-induced liver cancer in this mouse model that will be a useful tool to reconstruct the molecular etiology of human hepatocarcinogenesis.

Non‑infective occupational risk factors for hepatocellular carcinoma: A review (Review)

Liver cancer is the second leading worldwide cause of cancer‑associated mortalities. Hepatocellular carcinoma, which accounts for the majority of liver tumors, ranks fifth among types of human cancer. Well‑established risk factors for liver cancer include the hepatitis B and C viruses, aflatoxins, alcohol consumption, and oral contraceptives. Tobacco smoking, androgenic steroids, and diabetes mellitus are suspected risk factors. Current knowledge regarding non‑infective occupational risk factors for liver cancer is inconclusive. The relevance of liver disorders to occupational medicine lies in the fact that the majority of chemicals are metabolized in the liver, and toxic metabolites generated via metabolism are the predominant cause of liver damage. However, their non‑specific clinical manifestations that are similar in a number of liver diseases make diagnosis difficult. Furthermore, concomitant conditions, such as viral hepatitis and alcohol or drug abuse, may mask liver disorders that result from occupational hepatotoxic agents and block the demonstration of an occupational cause. The identification of environmental agents that result in human cancer is a long and often difficult process. The purpose of the present review is to summarize current knowledge regarding the association of non‑infective occupational risk exposure and HCC, to encourage further research and draw attention to this global occupational public health problem.

Distinct response of the hepatic transcriptome to Aflatoxin B1 induced hepatocellular carcinogenesis and resistance in rats

Aflatoxin is a natural potent carcinogen and a major cause of liver cancer. However, the molecular mechanisms of hepatocellular carcinogenesis remain largely unexplored. In this study, we profiled global gene expression in liver tissues of rats that developed hepatocellular carcinoma (HCC) from aflatoxin B₁ (AFB₁) administration and those that were AFB₁-resistant, as well as rats without AFB₁ exposure as a control. AFB₁ exposure resulted in extensive perturbation in gene expression with different functions in HCC and AFB₁ resistance (AR) samples. The differentially expressed genes (DEGs) in HCC sample were enriched for cell proliferation, cell adhesion and vasculature development that largely contribute to carcinogenesis. Anti-apoptosis genes were up-regulated in HCC sample whereas apoptosis-induction genes were up-regulated in AR sample. AFB₁ exposure also caused extensive alteration in expression level of lncRNAs. Among all the 4511 annotated lncRNAs, half of them were highly expressed only in HCC sample and up-regulated a group of protein-coding genes with cancer-related functions: apoptosis regulation, DNA repair, and cell cycle. Intriguingly, these genes were down-regulated by lncRNAs highly expressed in AR sample. Collectively, apoptosis is the critical biological process for carcinogenesis in response to AFB₁ exposure through changes in expression level of both protein-coding and lncRNA genes.

Coffee consumption and risk of hepatocellular carcinoma: a meta-analysis of eleven epidemiological studies

Growing evidence has shown that coffee consumption is inversely related with the risk of hepatocellular carcinoma. It is suggested that caffeine maintains strong antioxidative activity. With this property, coffee intake may lead to the inhibition of cell proliferation of liver cancer cells; also, some compounds contained in coffee can reduce the genotoxicity of aflatoxin B1 in vitro and lower the damage caused by some carcinogens. A computerized search was performed in PubMed to identify relevant articles published before August 2015. Eleven relevant studies were included with a total of 2,795 cases and 340,749 control subjects. According to the meta-analysis we performed, the pooled odds ratio (OR) from all included studies was 0.49 (95% confidence interval [CI] =0.46–0.52). The subgroup analysis indicated that the pooled ORs for Asian studies and other populations were 0.27 (95% CI =0.23–0.31) and 0.82 (95% CI =0.77–0.87), respectively. The overall pooled OR for high consumption was decreased to 0.21 (95% CI =0.18–0.25) and significance was observed. Among other populations, the pooled OR of subjects with high coffee consumption was 0.65 (95% CI =0.56–0.73) compared to the nondrinker. The corresponding OR of five Asian studies was 0.13 (95% CI =0.09–0.17). The findings from this meta-analysis further confirmed the inverse association between the coffee consumption and hepatocellular carcinoma risk with quantitative evidence. The protective effect can be detected among healthy population and patients with chronic liver diseases, and the consumption can also prevent the development of liver cirrhosis.

Genome-wide association study identified PLCE1- rs2797992 and EGFR- rs6950826 were associated with TP53 expression in the HBV-related hepatocellular carcinoma of Chinese patients in Guangxi

OBJECTIVE

The genome-wide association approach was employed to explore the association between single nucleotide polymorphisms (SNPs) and TP53 expression in the HBV-related hepatocellular carcinoma (HCC) of Chinese patients in Guangxi.

METHODS

403 HBV-related HCC patients were recruited into this study and classified according to the TP53 expression in the cancer by immunohistochemistry. DNA was extracted from the cancer and genotyped with the Human ExomeBeadChip 12v1-1 system; quality control and principal-component analysis (PCA) were applied for data analysis.

RESULTS

The Genome-wide association analysis indicated that rs2797992 with a P value of 4.35 × 10(-5) locus in PLCE1 gene and rs6950826 with a P value of 2.2 × 10(-3) locus in EGFR gene were associated with TP53 expression in the HCC. A allele of rs2797992 predicted a decreased risk for TP53 expression in HCC. In contrast, A allele of rs6950826 increased the risk for TP53 expression. There was no strong LD locus in the tested regions. PLCE1 and EGFR were associated with TP53 in pathway and at HCC mRNA level.

CONCLUSION

rs2797992 of PLCE1 gene and rs6950826 of EGFR gene are associated with TP53 expression, but not with the prognosis of HBV-related HCC in HBV-related HCC of Chinese patients in Guangxi.

The Epidemiological Investigation on the Risk Factors of Hepatocellular Carcinoma: A Case-Control Study in Southeast China

Incidence of hepatocellular carcinoma (HCC) ranked the fifth in male and ninth in the female counterparts, and 50% of incidence HCC cases were occurred in China with high hepatitis B virus (HBV) prevalence. HCC has seriously compromised the health status of general population in China. A case-control study of 314 HCC cases and 346 controls was conducted in Xiamen, which is an epidemic area in China for both hepatitis B infection and HCC. Face-to-face interview was conducted to gather information on demographic characteristics as well as exposure of environmental factors. Commercial enzyme-linked immunosorbent assay kits were used to determine the status of serological markers of HBV infection. Odds ratios and 95% confidence intervals were estimated by using unconditional logistic regression. Multivariate unconditional logistic regression analysis was applied to evaluate the potential interactions of variables or confounders.As expected, HBV and alcohol intake still are the major risk factors of HCC. Liver disease history and passive smoking are also associated with elevated HCC risk. Indoor air pollution and pesticide exposure have newly identified as risk factors of HCC. Fruit and tea intake can significantly lower the HCC risk.The application of HBV vaccine and reduction on alcohol intake should be further promoted in high-risk population. Fruit and tea can be served as chemoprevention in daily life due to their high accessibility.

Characteristics of liver cancer at Khmer-soviet Friendship Hospital in Phnom Penh, Cambodia

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most frequent cancers in South East Asian countries including Cambodia, where prevalence of chronic carriers of hepatitis B and C virus (HBV and HCV) is reported to be very high. We reviewed HCC cases admitted to a cancer hospital in Phnom Penh, which is the only one hospital for cancer treatment and care in Cambodia during the study period.

MATERIALS AND METHODS

Information was collected from medical records of 281 cases (210 males and 71 females) diagnosed as primary HCC from 2006 to 2011.

RESULTS

The subjects were 7-81 years old with a median age of 53 years. Hypochondriac pain was the most common complained symptom (74%). One third of the cases presented with jaundice. Nearly half had ascites at their first visit. One third had liver cirrhosis. Nearly three fourths of the cases presented with tumor sized more than 50 mm in diameter, and in almost all cases (97.4%) the size was more than 20 mm. Among 209 subjects tested, hepatitis virus carriers were 75.6%; 46.4% for HBV only, 21.5% for HCV only, and 7.7% for both viral infections. Median age of patients with HBV was about ten years younger than those with HCV.

CONCLUSIONS

This study revealed the characteristics of HCC cases in Cambodia, although there were several limitations. Most HCC cases were infected with HBV and/or HCV, and diagnosed at late stages with complications. This implicated that public health intervention to prevent HBV and HCV infection is of high priority.

Validation of a predictive modeling approach to demonstrate the relative efficacy of three different schedules of the AKT inhibitor AZD5363

PURPOSE

Intermittent dosing of inhibitors of the PI3K/AKT/mTOR network offers the potential to maximize the therapeutic margin. Here, we validate a predictive modeling approach to establish the relative efficacy of continuous and two intermittent dosing schedules of the AKT inhibitor AZD5363.

METHODS

A mathematical model of pharmacokinetics, pharmacodynamics and anti-tumor effect was constructed based upon experimental data from dosing regimens that give constant and transient inhibition of the AKT pathway.

RESULTS

Continuous and intermittent dosing of AZD5363 inhibited growth of BT474c xenografts and caused dose- and time-dependent inhibition of AKT substrate phosphorylation. Both dosing schedules inhibited proliferation, but a higher intermittent dose also induced apoptosis. The mathematical model described this pharmacodynamic and efficacy data well, for both monotherapy and combination dosing with docetaxel, and predicted that equivalent efficacy could be achieved at 1.3- and 1.7× continuous dose when AZD5363 was dosed intermittently for 4 and 2 days per week, respectively. These predictions were confirmed in two independent xenograft models. Moreover, the model also correctly predicted the relative efficacy of three different sequences of intermittent dosing of AZD5363 with docetaxel.

CONCLUSIONS

Equivalent anti-tumor activity to continuous dosing can be achieved at modestly increased intermittent doses of AZD5363. These intermittent dosing regimens may potentially overcome tolerability issues seen with continuous dosing and enable greater flexibility of dosing schedule in combination with other agents, including chemotherapy.

Integration of tumour and viral genomic characterizations in HBV-related hepatocellular carcinomas

BACKGROUND AND AIM

Hepatocellular carcinoma (HCC) is the most common liver cancer. We characterised HCC associated with infection compared with non-HBV-related HCC to understand interactions between viral and hepatocyte genomic alterations and their relationships with clinical features.

METHODS

Frozen HBV (n=86) or non-HBV-related (n=90) HCC were collected in two French surgical departments. Viral characterisation was performed by sequencing HBS and HBX genes and quantifying HBV DNA and cccDNA. Nine genes were screened for somatic mutations and expression profiling of 37 genes involved in hepatocarcinogenesis was studied.

RESULTS

HBX revealed frequent non-sense, frameshift and deletions in tumours, suggesting an HBX inactivation selected in HCC. The number of viral copies was frequently lower in tumour than in non-tumour tissues (p=0.0005) and patients with low HBV copies in the non-tumour liver tissues presented additional risk factor (HCV, alcohol or non-alcoholic steato-hepatitis, p=0.006). P53 was the most frequently altered pathway in HBV-related HCC (47%, p=0.001). Furthermore, TP53 mutations were associated with shorter survival only in HBV-related HCC (p=0.02) whereas R249S mutations were identified exclusively in migrants. Compared with other aetiologies, HBV-HCC were more frequently classified in tumours subgroups with upregulation of genes involved in cell-cycle regulation and a progenitor phenotype. Finally, in HBV-related HCC, transcriptomic profiles were associated with specific gene mutations (HBX, TP53, IRF2, AXIN1 and CTNNB1).

CONCLUSIONS

Integrated genomic characterisation of HBV and non-HBV-related HCC emphasised the immense molecular diversity of HCC closely related to aetiologies that could impact clinical care of HCC patients.

Impact of mannose-binding lectin 2 polymorphism on the risk of hepatocellular carcinoma: a case-control study in Chinese Han population

Background

Mannose-binding lectin2 (MBL2) is implicated in the host immune response, but there are limited data about MBL2 polymorphisms and hepatocellular carcinoma (HCC) risk. This study aimed to investigate the relationship between the MBL2 rs7096206 polymorphism and HCC risk in a Chinese Han population.

Methods

A population-based case-control study of 220 HCC patients and 220 age- and gender-matched healthy control subjects from a Chinese Han population was conducted. Genomic DNA was extracted from blood samples, and the presence of the MBL2 polymorphism rs7096206 was assessed using matrix-assisted laser desorption-ionization time-of-flight mass spectrometry. Conditional logistic regression was performed to assess the risk of HCC by determining odds ratios and 95% confidence intervals (CIs).

Results

The odds of HCC among carriers of CG and GG genotypes were 7.33 (95% CI, 2.53–21.29) and 12.48 (95% CI, 2.08–74.90), respectively. In the dominant genetic model, GG+CG carriers had an approximately 8-fold increased risk (95% CI, 2.83–22.62) compared with those with the CC genotype. The G allele was significantly associated with elevated HCC risk, with an odds ratio of 6.83 (95% CI, 2.90–16.10).

Conclusions

Our findings suggest that the MBL2 polymorphism rs7096206 is associated with HCC susceptibility and has the potential to serve as a biomarker to detect populations at increased HCC risk.

The p53 mutation spectrum in hepatocellular carcinoma from Guangxi, China : role of chronic hepatitis B virus infection and aflatoxin B1 exposure

BACKGROUND & AIMS

p53 is one of the most frequently mutated human tumour suppressor genes. Chronic infection with hepatitis B virus (HBV) and exposure to aflatoxin B1 (AFB1) induces p53 mutations in hepatocellular carcinoma (HCC) tissue. The aims of present study are to investigate the p53 mutation spectrum in HBV- and AFB1-related hepatocarcinogenesis in patients with hepatocellular carcinoma (HCC) in Guangxi, China.

METHODS

Tumour and adjacent liver tissue were collected from 397 HCC patients who were subdivided into HBV(+)/AFB1(+), HBV(+)/AFB1(-), HBV(-)/AFB1(+) and HBV(-)/AFB1(-) four groups. All 11 exons of the p53 gene were PCR-amplified and sequenced. Immunohistochemistry was used to evaluate the effect of mutations on the expression of p53 protein.

RESULTS AND CONCLUSIONS

P53 mutations were detected in 223 HCC samples, 13 adjacent liver tissue samples and only 1 of 68 normal liver tissue samples. The mutation sites concentrated at exon 4, 5, 6, 7, 8, 9 and no mutation was detected in exon 1, 2, 3, 10 and 11. The most frequently occurring mutation was in codon 249 (R249S) in exon 7. Patients in the HBV(+)/AFB1(+) and HBV(-)/AFB1(+) groups had significantly higher mutation rates compared with patients in the HBV(+)/AFB1(-) and HBV(-)/AFB1(-) groups. P53 mutation status and HBV/AFB1 status were independent predictors of tumour recurrence after surgery. Immunohistochemical analysis revealed that p53 gene mutations were correlated with the p53 expression. In Guangxi area, the significant association between AFB1-induced p53 mutations and the expression of p53 protein suggest an important role for p53 mutations in carcinogenesis of HCC.

Natural variations of copper and sulfur stable isotopes in blood of hepatocellular carcinoma patients

The widespread hypoxic conditions of the tumor microenvironment can impair the metabolism of bioessential elements such as copper and sulfur, notably by changing their redox state and, as a consequence, their ability to bind specific molecules. Because competing redox state is known to drive isotopic fractionation, we have used here the stable isotope compositions of copper ((65)Cu/(63)Cu) and sulfur ((34)S/(32)S) in the blood of patients with hepatocellular carcinoma (HCC) as a tool to explore the cancer-driven copper and sulfur imbalances. We report that copper is (63)Cu-enriched by ∼0.4‰ and sulfur is (32)S-enriched by ∼1.5‰ in the blood of patients compared with that of control subjects. As expected, HCC patients have more copper in red blood cells and serum compared with control subjects. However, the isotopic signature of this blood extra copper burden is not in favor of a dietary origin but rather suggests a reallocation in the body of copper bound to cysteine-rich proteins such as metallothioneins. The magnitude of the sulfur isotope effect is similar in red blood cells and serum of HCC patients, implying that sulfur fractionation is systemic. The (32)S-enrichment of sulfur in the blood of HCC patients is compatible with the notion that sulfur partly originates from tumor-derived sulfides. The measurement of natural variations of stable isotope compositions, using techniques developed in the field of Earth sciences, can provide new means to detect and quantify cancer metabolic changes and provide insights into underlying mechanisms.

Association between polymorphisms in tumor suppressor genes and oncogenes and risk of hepatocellular carcinoma: a case-control study in an HCC epidemic area within the Han Chinese population

Data concerning the risk of hepatocellular carcinoma (HCC) and specific single nucleotide polymorphisms (SNPs) in an HBV-free population are currently limited. Therefore, we performed a case-control study to investigate the association between SNPs and the risk of HCC in individuals without chronic HBV infection. A total of 160 Han Chinese patients with HCC and an identical number of healthy controls were enrolled in this study. rs1042522, rs10814325, rs17401966, and rs2279744 genotypes were determined using matrix-associated laser desorption ionization-time of flight-mass spectrometry (MALDI-TOF-MS). CG and GG genotypes in rs1042522 and heterozygote and homozygote in rs2279744 were significantly associated with an elevated risk of HCC. Homozygous mutation of rs1081432 conferred a 2.68-fold risk of HCC (95% CI 1.35-5.34); however heterozygosity was not statistically significant. rs17401966 heterozygosity or homozygosity was not significantly associated with a increased risk of HCC. Several polymorphisms associated with a significantly increased risk of HCC were identified. These may serve as biomarkers in evaluating HCC risk in the general population.

DNA markers in molecular diagnostics for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the one of the leading causes of cancer mortality in the world, mainly due to the difficulty of early detection and limited therapeutic options. The implementation of HCC surveillance programs in well-defined, high-risk populations were only able to detect about 40-50% of HCC at curative stages (Barcelona Clinic Liver Cancer stages 0 & 1) due to the low sensitivities of the current screening methods. The advance of sequencing technologies has identified numerous modifications as potential candidate DNA markers for diagnosis/surveillance. Here we aim to provide an overview of the DNA alterations that result in activation of cancer pathways known to potentially drive HCC carcinogenesis and to summarize performance characteristics of each DNA marker in the periphery (blood or urine) for HCC screening.

The association between exposure to aflatoxin, mutation in TP53, infection with hepatitis B virus, and occurrence of liver disease in a selected population in Hyderabad, India

Aflatoxin B1 is a carcinogen produced by Aspergillus flavus and a few related fungi that are often present in many food substances. It interacts synergistically with Hepatitis B or C virus (HBV, HBC) infection, thereby increasing the risk of hepatocellular carcinoma (HCC). The G to T transversion at the third position of codon 249 (AGG) of the TP53 gene, substituting arginine to serine, is the most common aflatoxin-induced mutation linked to HCC. This study examined mutations in TP53 by PCR-RFLP analysis and by measurement of an aflatoxin-albumin adduct as a biomarker for human exposure of aflatoxin B1 by indirect-competitive ELISA, in samples collected from healthy controls as well as patients with hepatitis in Hyderabad, Andhra Pradesh, India. A total of 238 blood samples were analyzed the presence of the G to T mutation. Eighteen of these samples were from HBV-positive subjects, 112 of these were from subjects who had HBV-induced liver cirrhosis, and 108 samples were taken from subjects without HBV infection or liver cirrhosis (control group). The G to T mutation was detected in 10 samples, 8 of which were from subjects positive to both HBV and aflatoxin-albumin adduct in blood (p=0.07); whilst two were from individuals who were HBV-negative, but positive for the aflatoxin-albumin adduct (p=0.14). The aflatoxin-albumin adduct was detected in 37 of 238 samples, 29 samples were from HBV-positive subjects and eight were from individuals who were positive for both HBV and the TP53 mutation (p=0.07). The concentration of aflatoxin-albumin adduct ranged from 2.5 to 667pg/mg albumin. Despite low incidence of the G to T mutation, its detection in subjects positive to aflatoxin-adducts is indicative of a strong association between the mutation and aflatoxin exposure in India.

Cytochrome P450 isoforms are differently up-regulated in aflatoxin B₁-exposed human lymphocytes and monocytes

CONTEXT

Aflatoxins (AFs) are highly hazardous mycotoxins with potent carcinogenic, mutagenic and immune disregulatory properties. Cytochrome P450 (CYP) isoforms are central for enhanced AFB₁ toxicity in situ. It remains to be seen whether and how these AFB₁ activators work in human leukocytes.

OBJECTIVE

To investigate the involvement of CYP isoforms in AFB₁ toxicity of circulating mononuclear cells, we examined the impact of environmentally relevant levels of AFB1 on lymphocytes and monocytes.

MATERIALS AND METHODS

Very low and moderate doses of AFB₁ with/without CYP inducers on transcription of key CYP isoforms and toll-like receptor 4 (TLR4) were examined in human lymphocytes, monocytes and HepG2 cells; cell cycle distribution and viability were also analyzed in AFB₁-exposed lymphocytes and monocytes.

RESULTS

Only CYP1A1, CYP1B1, CYP3A4, CYP3A5 and CYP3A7 expressed in lymphocytes and monocytes. TLR4 much more expressed in monocytes than in lymphocytes, but HepG2 showed little TLR4 transcription. While CYP1A1, CYP1B1 and CYP3A4 were highly induced by AFB₁ in monocytes, in lymphocytes only CYP1A1 was induced. Among CYP1A1, CYP1B1 and CYP3A4 only CYP1A1 responded to low and moderate levels of AFB₁. Enhanced transcripts of CYPs by AFB₁ yielded little synergies on TLR4 transcription in lymphocytes and monocytes. Cell cycle arrest and necrosis were also detected in AFB₁-exposed lymphocytes and monocytes.

CONCLUSIONS

Our novel findings indicate that AFB₁ more intensively stimulates CYP genes expression in monocytes than in lymphocytes. Mechanistically, this could explain a more pronounced immunotoxicity of AFB₁ in myeloid than in lymphoid lineage cells in vitro/situ/vivo.

Mutations in TP53, CTNNB1 and PIK3CA genes in hepatocellular carcinoma associated with hepatitis B and hepatitis C virus infections

Hepatocellular carcinoma (HCC) is the third leading cause of cancer death worldwide. Hepatocarcinogenesis is a multistep process mainly associated with persistent infection with hepatitis B (HBV) or C (HCV) viruses and always involving the accumulation of genetic alterations over decades of chronic liver disease. Mutations in TP53 and CTNNB1 genes are considered the cancer drivers for HCC development with variable frequencies depending on the etiology. Here we present a comprehensive review evaluating somatic mutations in TP53 and CTNNB1 genes in HBV- and HCV-related HCCs. Moreover, we report the mutational analysis of TP53 (exons 4-9) and CTNNB1 (exon 3) as well as PIK3CA (exon 9) genes in HCC from Southern Italy. The overall mutation frequency of TP53 and CTNNB1 was 33.3%, while hotspot variations in PIK3CA were completely absent. CTNNB1 mutations were significantly associated with young age (P=0.019) and moderately/poorly differentiated HCV-related HCC (P=0.015). The extended analysis of genetic alterations will help to identify molecular markers for liver cancer prevention, diagnosis and treatment of HBV and HCV-associated liver cancer.

Association between TP53 R249S mutation and polymorphisms in TP53 intron 1 in hepatocellular carcinoma

Over 100 single nucleotide polymorphisms (SNP) are validated in the TP53 tumor suppressor gene. They define haplotypes, which may differ in their activities. Therefore, mutation in cancer may occur at different rates depending upon haplotypes. However, these associations may be masked by differences in mutations types and causes of mutagenesis. We have analyzed the associations between 19 SNPs spanning the TP53 locus and a single specific aflatoxin-induced TP53 mutation (R249S) in 85 in hepatocellular carcinoma cases and 132 controls from Thailand. An association with R249S mutation (P = 0.007) was observed for a combination of two SNPs (rs17882227 and rs8064946) in a linkage disequilibrium block extending from upstream of exon 1 to the first half of intron 1. This domain contains two coding sequences overlapping with TP53 (WRAP53 and Hp53int1) suggesting that sequences in TP53 intron 1 encode transcripts that may modulate R249S mutation rate in HCC.

Hepatitis B virus genetic variation and TP53 R249S mutation in patients with hepatocellular carcinoma in Thailand

Chronic hepatitis B virus (HBV) infection and dietary exposure to aflatoxin B1 (AFB1) are major risk factors for hepatocellular carcinoma (HCC). The aim of this study was to evaluate the role of HBV genetic variation and the R249S mutation of the p53 gene, a marker of AFB1-induced HCC, in Thai patients chronically infected with HBV. Sixty-five patients with and 89 patients without HCC were included. Viral mutations and R249S mutation were characterized by direct sequencing and restriction fragment length polymorphism (RFLP) in serum samples, respectively. The prevalences of T1753C/A/G and A1762T/G1764A mutations in the basal core promotor (BCP) region were significantly higher in the HCC group compared to the non-HCC group. R249S mutation was detected in 6.2% and 3.4% of the HCC and non-HCC groups, respectively, which was not significantly different. By multiple logistic regression analysis, the presence of A1762T/G1764A mutations was independently associated with the risk of HCC in Thai patients.

Detection of cancer-specific epigenomic changes in biofluids: powerful tools in biomarker discovery and application

The genetic and epigenetic material originating from tumour that can be found in body fluids of individuals with cancer harbours tumour-specific alterations and represents an attractive target for biomarker discovery. Epigenetic changes (DNA methylation, histone modifications and non-coding RNAs) are present ubiquitously in virtually all types of human malignancies and may appear in early cancer development, and thus they provide particularly attractive markers with broad applications in diagnostics. In addition, because changes in the epigenome may constitute a signature of specific exposure to certain risk factors, they have the potential to serve as highly specific biomarkers for risk assessment. While reliable detection of cancer-specific epigenetic changes has proven to be technically challenging, a substantial progress has been made in developing the methodologies that allow an efficient and sensitive detection of epigenomic changes using the material originating from body fluids. In this review we discuss the application of epigenomics as a tool for biomarker research, with the focus on the analysis of DNA methylation in biofluids.

Association between HBX status, aflatoxin-induced R249S TP53 mutation and risk of hepatocellular carcinoma in a case-control study from Thailand

Hepatocellular carcinoma (HCC) is associated with hepatitis B virus (HBV) chronicity and dietary exposure to aflatoxin, a mutagen targeting codon 249 of tumor suppressor TP53 (R249S mutation). Based on a case-control in Thailand, we have measured R249S and the status of HBX gene in plasma DNA of 176 cases and 133 referents. Detection of HBX complete sequences was associated with R249S in HCC with no documented prior cirrhosis but not in HCC developing in a context of cirrhosis or in non-cancer chronic liver diseases. Thus, R249S may specifically cooperate with HBX in a pathway to HCC that bypasses cirrhosis.