Association of xenobiotic-metabolizing genes polymorphisms with cervical cancer risk in the Tunisian population.

BACKGROUND: Host genetic characteristics and environmental factors interactions may play a crucial role in cervical carcinogenesis. We investigated the impact of functional genetic variants of four xenobiotic-metabolizing genes (AhR, CYP1A1, GSTM1, and GSTT1) on cervical cancer development in Tunisian women. METHODS: The AhR gene polymorphism was analyzed using the tetra-primer ARMS-PCR, whereas the CYP1A1 polymorphism genotypes were identified by PCR-RFLP. A multiplex ligation-dependent polymerase chain reaction approach was applied for the analysis of GSTM1 and GSTT1 polymorphisms. RESULTS: The homozygous A/A genotype of the AhR gene (rs2066853) and the heterozygous T/C genotype of the CYP1A1 SNP (CYP1A1-MspI) appeared to be associated with an increased risk of cervical tumorigenesis (ORa = 2.81; ORa = 5.52, respectively). Furthermore, a significantly increased risk of cervical cancer was associated with the GSTT1 null genotype (ORa = 2.65). However, the null GSTM1 genotype showed any significant association with the risk of cervical cancer compared to the wild genotype (ORa = 1.18; p = 0.784). Considering the combined effect, we noted a significantly higher association with cancer risk for individuals with at least two high-risk genotypes of CYP1A1/GSTT1 (ORa = 4.2), individuals with at least two high-risk genotypes of CYP1A1/GSTT1/AhR (ORa = 11.3) and individuals with at least two high-risk genotypes of CYP1A1/GSTM1/GSTT1/AhR exploitation low-risk genotype as a reference. CONCLUSION: This study indicated that the single-gene contribution and the combined effect of xenobiotic-metabolizing gene polymorphisms (AhR, CYP1A1-MspI, GSTM1, and GSTT1) may have a considerable association with increased cervical cancer risk.

Association between the ELAVL1 gene single nucleotide polymorphisms and the Genetic Susceptibility to cervical cancer by high resolution melting in a Tunisian population.

BACKGROUND: Human papillomavirus is the major cause of cervical cancer, but only few cases develop into cancer. Nevertheless, HuR (ELAVL1) gene has been implicated in the oncogenesis of certain cancers. The correlation between ELAVL1 gene and the risk of cervical cancer remains unclear. Therefore, this study investigated the effect of ELAVL1 gene polymorphisms (SNPs) in cervical cancer development in Tunisian women. METHOD: ELAVL1 gene SNPs: ELAVL1 rs12983784 T > C, ELAVL1 rs14394 T > C, ELAVL1 rs74369359 G > T, ELAVL1 rs35986520 G > A, ELAVL1 rs10402477 C > T, ELAVL1 rs12985234 A > G and ELAVL1 rs2042920 T > G, were genotyped by High resolution melting (HRM). SNPStats software was used to perform linkage disequilibrium (LD) and haplotype analysis. RESULTS: Comparing the cervical cancer patients with healthy control participants, the SNPs rs12983784 (P = 0.032), rs74369359 (p = < 10- 3) and rs10402477 (P = 0.001) were associated with an increased cervical cancer risk. Contrary to the SNPs rs14394, rs7469359, rs35986520, rs12985234 and rs2042920 (p˃0.05). The haplotype analysis of the seven SNPs of ELAVL1 gene showed that there is no association between the different haplotypes and a possible risk of cervical cancer disease. Moreover, there was a significant Linkage disequilibrium between rs35986520 and rs2042920 (D'=0.9972) and between rs2042920 and rs10402477 (D'=0.9977). CONCLUSION: Our results indicated that genetic variants in the ELAVL1 gene might be associated with susceptibility to cervical cancer in the Tunisian population.

A bioactivity guided study on the antibacterial activity of Hertia cheirifolia L. extracts.

This study was carried out with the objective to investigate the antibacterial activity of Hertia cheirifolia L. extracts against Gram-positive and Gram-negative strains including Staphylococcus aureus (ATCC 6538), Bacillus subtilis (ATCC 6633), Bacillus licheniformis, Esherichia coli (ATCC 8739), Pseudomonas aeruginosa (ATCC 9027), Salmonella enterica (CIP 8039) and Salmonella typhimirium. The results of this antibacterial screening showed that the ethyl acetate (EtOAc) extracts had the best activity against the tested microorganisms. A bioassay-oriented fractionation approach for the more active extract (roots ethyl acetate extract) led to the obtaining five sub-fractions. Furthermore, these sub-fractions were also tested for antimicrobial activity and the best results were obtained for the roots EtOAc sub-fraction (C) with MICs values between 0.039 and 0.156 mg/mL. Reversed-phase high performance liquid chromatography (RP-HPLC) analysis indicated that the major phenolic components of active (EtOAc) extracts and sub-fraction (C) are fisetin hydrate (82.06%), trans cinnamic acid (63.66%), gallic acid (38.97%) and myricetin (20.92%). These results may help to improve these natural antibacterial substances that could serve as selective agents for bacterial diseases.

Naringin inhibits the invasion and migration of human glioblastoma cell via downregulation of MMP-2 and MMP-9 expression and inactivation of p38 signaling pathway.

Gliomas are the most common and malignant primary brain tumors. They are associated with a poor prognosis despite the availability of multiple therapeutic options. Naringin, a common dietary flavonoid abundantly present in fruits and vegetables, is believed to possess strong anti-proliferative and anti-cancer properties. However, there are no reports describing its effects on the invasion and migration of glioblastoma cell lines. Our results showed that the treatment of U251 glioma cell lines with different concentrations of naringin inhibited the invasion and migration of these cells. In addition, we revealed a decrease in the levels of matrix metalloproteinases (MMP-2) and (MMP-9) expression as well as proteinase activity in U251 glioma cells. In contrast, the expression of tissue inhibitor of metalloproteinases (TIMP-1) and (TIMP-2) was increased. Furthermore, naringin treatment decreased significantly the phosphorylated level of p38. Combined treatment with a p38 inhibitor (SB203580) resulted in the synergistic reduction of MMP-2 and MMP-9 expressions correlated with an increase of TIMP-1 and TIMP-2 expressions and the anti-invasive properties. However, p38 chemical activator (anisomycin) could block these effects produced by naringin, suggesting a direct downregulation of the p38 signaling pathway. These data suggest that naringin may have therapeutic potential for controlling invasiveness of malignant gliomas by inhibiting of p38 signal transduction pathways.

ANGPTL4 variants E40K and T266M are associated with lower fasting triglyceride levels and predicts cardiovascular disease risk in Type 2 diabetic Tunisian population.

BACKGROUND: Angiopoietin-like protein 4 (ANGPTL4) is a metabolic factor that increases plasma triglyceride levels by inhibiting lipoprotein lipase (LPL). The objective of this study was to investigate the association of ANGPTL4 variants (E40K and T266M) with triglyceride levels and with cardiovascular risk factors, such as metabolic syndrome (MetS) and obesity in type 2 diabetic Tunisian population. METHODS: We investigated the effect of the tagging single nucleotide polymorphisms (SNPs) rs1044250 (T266M) and rs116843064 (E40K) with triglyceride (TG) levels and CAD risk factors in a cohort of 220 patients undergoing coronary angiography for the evaluation of stable CAD, all of whom had (type 2 diabetes) T2D and were at least overweight. Multivariate logistic regressions were performed on association studies. RESULTS: TT genotype of rs1044250 (T266M variant) showed a protective effect on CVD risk in CAD group patients (OR 1.92, 95% CI 0.601.42, p =0.05) compared with control Group patients (OR 1.17, 95% CI 0.70-1.66, p = 0.72). Likewise, GA genotype of rs116843064 (E40K variant): (OR 0.74, 95% CI 0.54-1.65, p =0.01) for the CAD group compared with control Group patients (OR 1.12, 95% CI 0.68-1.74, p = 0.074). CONCLUSIONS: ANGPTL4 variants are associated with, not only lower fasting triglyceride levels, but also a decreased cardiovascular risk in T2D Tunisian patients. So, T266M and E40K polymorphism predicts cardiovascular disease risk in Type 2 diabetic Tunisian population.

Toxic effects of methamidophos on paraoxonase 1 activity and on rat kidney and liver and ameliorating effects of alpha-tocopherol.

The role of alpha-tocopherol on nephrotoxicity and hepatotoxicity induced by methamidophos (MT) was investigated in wistar rats. Animals were given via gavage, for four weeks, a low dose of MT (MT1), a high dose of MT (MT2), vitamin E (200 mg/kg of bw) or both MT2 plus vitamin E (Vit E) and control group was given distillate water. MT treatment resulted in a significant decrease in the body weight of MT2-treated group. Moreover, MT-treated groups had significantly lower butyrylcholinesterase (p < 0.01) and paraoxonase 1 (PON1) activities compared with the control group (p < 0.05). However, MT2-treated group had significantly higher alkaline phosphatase activity compared with untreated rats (p < 0.05). Both MT-treated groups had significantly higher urea (p < 0.01) and uric acid levels (p < 0.05) compared with the control group. However, significant low uric acid level (p < 0.05) was noted in MT2 plus vit E-treated rats compared with MT2-treated group. Histopathological changes in organ tissues were observed in both MT-treated groups and MT2 plus vit E-treated rats. However, the damage was reduced in MT2 plus vit E-treated rats. Therefore, this study deduces that alpha-tocopherol administration may ameliorate the adverse effects of subacute exposure to MT on rat liver and kidney and this antioxidant can protect PON1 from oxidative stress induced by this organophosphorus pesticide. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 842-854, 2016.

A Novel Platinum-Maurocalcine Conjugate Induces Apoptosis of Human Glioblastoma Cells by Acting through the ROS-ERK/AKT-p53 Pathway.

Glioblastoma multiforme (GBM) is a highly malignant and aggressive primary brain tumor. In spite of an arsenal of therapeutic interventions, the prognosis of glioblastoma remains very poor. Cisplatin-based therapy is one of the most important chemotherapy treatments for GBM, although its efficacy is limited by drug resistance and undesirable side effects. In the present study, we designed a chimera molecule containing the platinum binding moiety MBL-III-7 (1) attached N-terminal to the sequence of d-maurocalcine (D-MCa), a protease-resistant and highly efficient cell-penetrating peptide (CPP) derived from the Tunisian chactid scorpion toxin, L-MCa. The concept behind this design is that MCa, through its cell retention properties, should reduce cell expulsion of the platinum complex and increase its efficiency. The anti-cancer properties of the synthesized platinum analogue Pt-MBL-III_7-D_MCa (Pt-1-DMCa) were assessed in human glioblastoma cells (U87) by assaying cell viability and apoptosis. The new molecule exhibited enhanced anti-cancer efficacy compared to cisplatin, especially at low doses. By inducing intracellular oxidative stress, Pt-1-DMCa potentiated platinum-induced DNA damage and led to enhanced p53 phosphorylation, followed by increased activation of both mitochondrial and death receptor pathways. Decreased phosphorylated AKT and ERK levels were associated with the apoptosis induced by the novel synthesized cisplatin analogue. Our results suggested that a chimera between platinum and a maurocalcine-derived CPP is a highly successful anti-cancer compound that works by targeting the intracellular redox system. Pt-1-DMCa is an interesting candidate for a preclinical assessment of platinum-based therapy in GBM treatments and possibly other cancer types.

Potential role of genetic polymorphisms in neoadjuvant chemotherapy response in breast cancer.

Chemoresistance leads to treatment failure, which can arise through different mechanisms including patients' characteristics. Searching for genetic profiles as a predictor for drug response and toxicity has been extensively studied in pharmacogenomics, thus contributing to personalized medicine and providing alternative treatments. Numerous studies have demonstrated significant evidence of association between genetic polymorphisms and response to neoadjuvant chemotherapy (NAC) in breast cancer. In this review, we explored the potential impact of genetic polymorphisms in NAC primary resistance through selecting a specific clinical profile. The genetic variability within pharmacokinetics, pharmacodynamics, DNA synthesis and repair, and oncogenic signaling pathways genes could be predictive or prognostic markers for NAC resistance. The clinical implication of these results can help provide individualized treatment plans in the early stages of breast cancer treatment. Further studies are needed to determine the genetic hosts of primary chemoresistance mechanisms in order to further emphasize the implementation of genotypic approaches in personalized medicine.

Arachidonic acid ω-hydroxylase CYP4A11: inter-ethnic variations in the 8590T>C loss-of-function variant.

The human Cytochrome P450 4A11 (CYP4A11) is a major ω-hydroxylase involved in the regulation of blood pressure in the kidney through the conversion of arachidonic acid into 20-hydroxyeicosatetraenoic acid (20-HETE). Previous studies have reported a significant association between the 8590T>C genetic variant of CYP4A11 and hypertension. Interestingly, several population-based studies have reported ethnic differences in the prevalence of hypertension, with the highest prevalence in African populations. The aim of this work was to determine the frequency and inter-ethnic comparison of the CYP4A11 (8590T>C) functional polymorphism, in five new ethnic groups: European (99 French Caucasians), African (36 Gabonese and 50 Senegalese), South American (60 Peruvians) and North African (53 Tunisians) populations, using polymerase chain reaction-single strand conformational polymorphism and sequencing strategies. We confirmed that the CYP4A11 (8590T>C) functional polymorphism exhibits inter-ethnic frequency differences. Noteworthy, the highest 8590C allele frequency was observed in the Tunisian (30.2%), followed by Senegalese (20%) populations. In addition, the CC genotype was only found in the Gabonese and Tunisian populations (5.6% and 8.4%, respectively). These populations may be of major interest to help to clarify the linkage between hypertension and CYP4A11 (8590T>C) genotype in African populations. These findings provide data for further studies that investigate the potential association of CYP4A11 (8590T>C) variant with an incidence of hypertension genesis in respect of ethnicity.

Inter-ethnic variability of three functional polymorphisms affecting the IMPDH2 gene.

Human type II inosine monophosphate dehydrogenase (IMPDH2) is a key enzyme in the purine nucleotide biosynthetic pathway and constitutes a pivotal biological target for immunosuppressant and antiviral drugs. Several Single Nucleotide Polymorphisms (SNP) affecting the IMPDH2 gene sequence have been reported with potential functional relevance and could impact drugs response. We aimed to determine the frequency of three of these polymorphisms, namely g.3375C>T (Leu(263)Phe), c.-95T>G and IVS7+10T>C, in Caucasians, Tunisians, Peruvians and Black Africans (Gabonese and Senegalese). The g.3375C>T and c.-95T>G polymorphisms are rare with a Minor Allele Frequency ≤1.0% in our populations, whereas the third variant, IVS7+10T>C, is more frequent and displays large interethnic variations, with an allelic frequency ranging from 14.6% in the French Caucasian population studied to less than 2% in Black African and Peruvian populations. This ethnic-related data might contribute to a better understanding of the variability in clinical outcome and/or dose adjustments of drugs that are IMPDH inhibitors such as mycophenolic acid.

Factors influencing plasma butyrylcholinesterase activity in agricultural workers.

We studied the influence of some factors on plasma butyrylcholinesterase activity (BChE) and we assessed the health status of agricultural workers and looked for the effects of chronic exposure to pesticides, in the aim to determinate factors that must be considered for interpretation of BChE, for occupational monitoring of workers exposed to pesticides. The study was carried out in 110 workers from the Sahel region of Tunisia exposed to pesticides and in 97 controls. All individuals have undergone clinical examination. BChE activity was measured by spectrophotometric method. The mean of BChE activity of workers was significantly lower than that of control group (P < 0.001). Among the 44% of farmworkers with at least one neurologic or neuropsychic symptom, 29% had BChE activity lower than 6000 IU/L. Headache was observed in 20% of workers. Ancientness of exposure equal to 10 years or more, last exposure dates back to 60 days or less, exposure for 2 days or more per week, exposure exceeding 150 h per year and to organophosphorus-carbamates mixture were implicated in significant decreases of BChE activity and can be considered as risk factors of cholinergic toxic effects. Thus, BChE activity is a useful indicator to monitor workers chronically exposed to pesticides. However, it should be accompanied by periodical health examination, taking into account risk factors, for an early identification of workers at increased risk.

Cytotoxicity, intracellular distribution and uptake of doxorubicin and doxorubicin coupled to cell-penetrating peptides in different cell lines: a comparative study.

One of the major obstacles which are opposed to the success of anticancer treatment is the cell resistance that generally develops after administration of commonly used drugs. In this study, we try to overcome the tumour cell resistance of doxorubicin (Dox) by developing a cell-penetrating peptide (CPP)-anticancer drug conjugate in aim to enhance its intracellular delivery and that its therapeutic effects. For this purpose, two cell-penetrating peptides, penetratin (pene) and tat, derived from the HIV-1 TAT protein, were chemically conjugated to Dox. The cytotoxicity, intracellular distribution and uptake were accessed in CHO cells (Chinese Hamster Ovarian carcinoma cells), HUVEC (Human Umbilical Vein Endothelial Cells), differentiated NG108.15 neuronal cell and breast cancer cells MCF7drug-sensitive or MDA-MB 231 drug-resistant cell lines. The conjugates showed different cell killing activity and intracellular distribution pattern by comparison to Dox as assessed respectively by MTT-based colorimetric cellular cytotoxicity assay, confocal fluorescence microscopy and FACS analysis. After treatment with 3 microM with Dox-CPPs for 2h, pene increase the Dox cytotoxicity by 7.19-fold in CHO cells, by 11.53-fold in HUVEC cells and by 4.87-fold in MDA-MB 231 cells. However, cytotoxicity was decreased in NG108.15 cells and MCF7. Our CPPs-Dox conjugate proves the validity of CPPs for the cytoplasmic delivery of therapeutically useful molecules and also a valuable strategy to overcome drug resistance.

Doxorubicin coupled to penetratin promotes apoptosis in CHO cells by a mechanism involving c-Jun NH2-terminal kinase.

Doxorubicin (Dox) has demonstrated potent activity in treating malignant lymphomas but its therapeutic efficacy is hampered by induction of cardiotoxicity. This side effect is related to the ability of the drug to generate reactive oxygen species in cells. Previously, we demonstrated that coupling Dox to penetratin (Pen), a cell penetrating peptide, represent a valuable strategy to overcome drug resistance in CHO cells. In the present study, we evaluated the consequences of the conjugation of Dox to Pen in term of apoptosis induction. When tested on CHO cells, Dox-Pen generated a typical apoptotic phenotype but at lower dose that needed for unconjugated Dox. Cell death induction was associated with chromatin condensation, caspase activation, Bax oligomerisation and release of cytochrome c. By using reactive oxygen species and c-jun NH2-terminal kinase (JNK) inhibitors, we prevented Dox- and Dox-Pen-induced CHO cell death. The chimeric soluble DR5 receptor that inhibits TRAIL induced cell death does not prevent Dox or Dox-Pen-induced cytotoxicity. These observations indicate that conjugation of Dox to cell penetrating peptide does not impair the ability of the drug to trigger cell death through activation of the intrinsic pathway involving c-Jun NH2-terminal kinase but could exhibit less toxic side effects and could warrant its use in clinic.

MALDI imaging mass spectrometry in ovarian cancer for tracking, identifying, and validating biomarkers.

BACKGROUND: Among biomarkers, cancer-antigen 125 (CA-125) is the most studied. We propose an analytical tool to track ovarian carcinoma biomarkers, that is, the MALDI mass spectrometry imaging. MATERIAL/METHODS: Ovarian carcinomas and benign ovaries were directly analyzed by MALDI-TOF-MS. After automatic profiling and mass spectrometry imaging analyses, hierarchical clustering based on principal component analysis in nonsupervised mode was carried out. On the same samples, preparations were performed to investigate peptides, then proteins, followed by high mass proteins, in an automatic profiling to specific signatures for diagnosis. Using tissue bottom-up strategy on tissue digestion, and mass spectrometry imaging after by shotgun sequencing by nalano-LC-IT-MS in MS/MS mode from washing samples from on tissue digested peptides, several biomarkers were found. RESULTS: A list of specific biomarkers from the ovarian carcinoma regions was obtained and classified as proteins associated with cell proliferation, involved in immune response modulation, signaling to the cytoskeleton, and tumor progression. These specific biomarkers were then validated by immunocytochemistry using Tag-mass technology, cell biology, Western blot, and by PCR (using SKOV-3 ovarian epithelial cancer cells). A link between the immune regulation (innate immunity, tolerance) and virus cause is also discussed. CONCLUSIONS: From the biomarkers identified, proteins involved in immune response modulation and cell proliferation have been pointed out in this study. Two new markers have been identified using such a strategy, that is, fragment C-terminal of the PSME1 (Reg-Alpha) and mucin-9.

Simple analytical method for determination of pesticide residues in human serum by liquid chromatography tandem mass spectrometry.

The aim of this study was to develop an analytical method for the determination of residues of organophosphorus and carbamate pesticides which are widely used in Tunisia. This method involves a liquid-liquid extraction procedure followed by liquid chromatography tandem mass spectrometry (LC/MS/MS) for the identification and quantification of compounds. Ionization of molecules was performed by the electrospray mode. Multiple reactions monitoring (MRM) was the acquisition mode used for the monitoring of two MS/MS transitions for each compound. The average recoveries obtained, at three different fortification levels, ranged between 65% and 106% for most of the pesticides studied, except for methamidophos (lower than 25%).The linearity of the method was in the range of 5 to 50 micro g/L with a correlation coefficient from 0.995 to 0.999, depending on the analyte. The estimated limit of detection and limit of quantification were 2 micro g/L and 5 micro g/L, respectively. The precision of the analytical procedure was satisfactory and the coefficients of variation, evaluated at three concentration levels were lower than 15% for most pesticides studied. The application of the method was investigated in a population of agricultural workers chronically exposed to various pesticides some of which, such as carbofuran, carbendazim, methomyl and pirimicarb, were detected in some serum samples.

Natural dietary compound naringin inhibits glioblastoma cancer neoangiogenesis.

BACKGROUND: Flavonoids, which existed nearly in all fruits and vegetables, are considered as a class of plant-secondary metabolites with a polyphenolic structure and have properties with health-improving potential. Yet, not so many experimental focus on the benefits of flavonoid in vivo after external application. Here we assessed the impacts of naringin in vitro and in vivo in the human glioma U-87 cells implanted into athymic mice. METHODS: Tumor size and animal survival time were followed in naringin-treated mice bearing subcutaneous gliomas. To define the effects of naringin on angiogenesis, in vitro, tube formation and migration were assayed using endothelial HUVEC cell line. RESULTS: Low concentration of naringin remarkably inhibited tubulogenesis and reduced cell invasion. Moreover, naringin has been shown to have a toxicity effect on U-87 cells in a dose-dependent way. Furthermore, naringin administration (120 mg/kg/day) applies serious anti-cancer belongings on glioblastoma, as demonstrated by a slow cancer progression. CONCLUSIONS: Our study has provided the first evidence on the antitumor effect of naringin, which is somehow due to the inhibition of invasion and angiogenesis.

IGF1 polymorphisms and colon cancer risk in Tunisian population.

BACKGROUND: Insuline-like growth factor I (IGF1) is a peptide growth factor that promotes cell proliferation and inhibits apoptosis. AIM: To examine the association of genetic variants in IGF1 (rs12423791, rs1019731, rs5742632, rs2033178 and rs2373722) with risk of colon cancer in Tunisia. METHODS: The study included 76 formalin-fixed paraffin embedded primary colorectal carcinomas and paired normal colon. The five IGF1 polymorphisms were determined by polymerase chain-restriction fragment length polymorphism (PCR-RFLP). RESULT: A significant differences in genotypes and alleles frequency of the five examined IGF1 polymorphisms was determined between tumor and healthy tissues of colon cancer patients (P<0,01). While, no significant association was found between genetic variation in IGF1 variants and clinic-pathological parameters in tumors tissues. Expect for rs2373722, a statistically significant correlation was detected between tumor localization and the presence of the (A) mutated allele (OR=0,49; 95% CI 0,25-0,99; P=0,03). CONCLUSION: This analysis shows that IGF1gene polymorphisms rs12423791, rs1019731, rs5742632, rs2033178 and rs2373722 are associated with the risk of colon cancer in Tunisian population.

Association between HER2 and IL-6 genes polymorphisms and clinicopathological characteristics of breast cancer: significant role of genetic variability in specific breast cancer subtype.

Clinical implications of single nucleotide polymorphisms (SNPs) in breast cancer have been explored to determine the impact of SNP in modulating the pathogenesis of breast cancer. This study aimed to evaluate the association between HER2 (rs2517956) and (IL-6) (rs1800795 and rs2069837) and clinicopathological characteristics in HER2-positive and HER2-negative breast cancer in Tunisian women. A retrospective cohort study included 273 patients. Genomic DNA was extracted from peripheral blood samples, and genotyping of selected SNP was performed by PCR-RFLP assays. Statistical analysis was then carried out to assess genotypic frequencies and genetic association in relation to breast cancer subtypes. SHEsis software was applied to IL-6 haplotypic structure analysis. The distribution of genotype frequencies of rs2517956, rs1800795 and rs2069837 showed no statistically difference between HER2-positive and HER2-negative breast cancer. HER2 (rs2517956) was associated with tumor size (p = 0.01) and age at diagnosis (p = 0.02) in HER2-negative breast cancers, but no significant association was observed in HER2-positive breast cancer. For IL-6 gene, none of the clinicopathological parameters were associated with rs1800795 and rs2069837 in both breast cancer subtypes (p > 0.05). SHEsis analysis revealed a high linkage disequilibrium between rs1800795 and rs2069837; differences in the distribution of IL-6 two loci haplotypes were statistically negative between HER2-positive and HER2-negative breast cancer (p = 0.20) which confirmed no association with HER2 overexpression. This study demonstrates that rs2517956 is associated with clinicopathological characteristics in HER2-negative breast cancer, which could have a differential prognostic role compared to HER2-positive breast cancer.

Conjugation of doxorubicin to cell penetrating peptides sensitizes human breast MDA-MB 231 cancer cells to endogenous TRAIL-induced apoptosis.

Previous work from our laboratory has shown that coupling doxorubicin (Dox) to cell penetrating peptides (Dox-CPPs) is a good strategy to overcome Dox resistance in MDA-MB 231 breast cancer cells. We also reported that, in contrast to unconjugated Dox-induced cell death, the increase in apoptotic response does not involve the mitochondrial apoptotic pathway. In this study, we demonstrate that both Dox and Dox-CPPs can increase the density of the TRAIL receptors DR4 and DR5 at the plasma membrane and moderately sensitize MDA-MB 231 cells to exogeneously added recombinant TRAIL, as has already been shown for other chemotherapeutic drugs. Moreover, we show that Dox-CPPs, used alone, induce the clustering of TRAIL receptors into ceramide-enriched membrane lipid rafts, a property not shared by unconjugated Dox and that this process is due to the generation of ceramide during Dox-CPPs treatment. In addition, MDA-MB 231 cells were found to express TRAIL and we show that the increased apoptotic rate induced by Dox-CPPs is due to the sensitization of MDA-MB 231 cells to endogenous TRAIL. The capacity of Dox-CPPs to sensitize cancer cells to physiologic amounts of TRAIL suggests that, in addition to their efficiency in combination chemotherapy, these compounds might increase the response of tumor cells to cytotoxic lymphocyte-mediated killing via TRAIL.

Involvement of C-jun NH2-terminal kinase and apoptosis induced factor in apoptosis induced by deglycosylated bleomycin in laryngeal carcinoma cells.

In our previous studies, we demonstrated that the deglycosylation of bleomycin-A2 (BLM-A2) does not affect the capacity of this drug to induce cell death by apoptosis in a caspase-independent manner in laryngeal cancer cells (HEp-2), but suppresses the ability of BLM-A2 to induce ROS formation. We have now investigated the consequence of BLM-A2 deglycosylation in terms of the involvement of apoptotic pathways in HEp-2 cells. Apoptosis induced by bleomycin-A2 and deglyco-BLM-A2 is associated with the release of cytochrome c and AIF. Only Bax was oligomerized with BLM-A2-induced HEp-2 cell death. BLM-A2 and deglyco-BLM-A2-induced apoptosis depended on JNK activation but was independent of death receptors expression. In contrast, both of these drugs would sensitize HEp-2 cells to death receptor ligand-induced cell death. These observations indicate that the deglycosylation of BLM does not impair the ability of the drug to trigger cell death through activation of the intrinsic pathway by the release of AIF responsible for mitochondrial permeability and chromatin condensation independent of caspases activation.