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S Parodi

Publications and source records attributed to S Parodi.

At least 19 recordsLinked to original sources
PubMed2007

Inhibition of a protein-protein interaction between INI1 and c-Myc by small peptidomimetic molecules inspired by Helix-1 of c-Myc: identification of a new target of potential antineoplastic interest.

c-Myc is a transcription modulator proto-oncogene. When overexpressed, it becomes an important contributor to the multi-hit process of malignant transformation. In two earlier papers in this journal (see refs. 19 , 20) we reported that retro-inverso peptidomimetic molecules inspired by the Helix-1 of c-Myc motif could be sequence-specific antiproliferative agents active in the low micromolar range. We also found that our peptides were not opening the four-alpha-helix Myc:Max bundle. Their antiproliferative activity in cancer cell lines needs the presence of side chains projecting outside of the bundle in the corresponding native H1 motif. This observation suggested interference with an external partner. In this study we investigated the INI1:Myc interaction. INI1 is a subunit of the SWI/SNF complex (component of the enhanceosome surrounding Myc:Max heterodimer). The INI1:Myc interaction was confirmed via pull down, ELISA, and fluorescence anisotropy assays. According to the length of INI1 fragments used, we calculated Kds ranging between 1.3x10(-6) and 4.8x10(-7) M. The three different techniques applied showed that the INI1:Myc interaction was also the target of our retro-inverso peptidomimetic molecules, which seem to bind specifically at INI1. A Myc binding, 21aa INI1 fragment (minimum interacting sequence), could inspire the synthesis of a new class of more selective c-Myc inhibitors.

Amino Acid Sequence↗
PubMed2006

Cis and trans regulatory elements in NPHS2 promoter: implications in proteinuria and progression of renal diseases.

Podocin (NPHS2) expression in podocytes is associated with variable degrees of proteinuria and progression to renal failure in different glomerular diseases that suggests different expression profiles in NPHS2 promoter. Three functional polymorphisms in NPHS2 promoter (-51T, -116T, and -535 insCTTTTTT(3)) were found determining strong downregulation (-73, -59, and -82%, respectively) of the reporter gene expression when transfected in podocytes. Electrophoretic mobility shift assay experiments showed that all wild-type variants (-51G, -116C, and -535 insCTTTTTT(2)) formed specific DNA-protein complexes with podocyte nuclear extracts that were abolished by the presence of the rare forms (-51T, -116T, and -535 insCTTTTTT(3)). In the case of -51G, upstream stimulatory factor-1 (USF1) was identified as the specific trans element in accord to binding inhibition experiments and USF1 RNAi silencing. Haplotype analysis of 204 normal controls and 545 patients with renal diseases (308 immunoglobulin (Ig)A nephropathy and 237 focal segmental glomerulosclerosis) evidenced that -116/-51 and -535/P2OL formed two blocks in strong linkage disequilibrium in both normal and pathological cohorts. The high NPHS2 promoter profile -116C/-51G haplotype was more frequent in patients with IgA nephropathy (P-value=0.005) and was associated with a better clinical outcome in terms of proteinuria and creatinine levels. Overall our study describes functional variants of NPHS2 promoter and characterizes trans-acting elements that modulate podocin expression in the kidney. High producer NPHS2 promoter haplotypes seem protective in patients with chronic glomerular diseases.

Adolescent↗
PubMed2006

Glomerular clusterin is associated with PKC-alpha/beta regulation and good outcome of membranous glomerulonephritis in humans.

Mechanisms for human membranous glomerulonephritis (MGN) remain elusive. Most up-to-date concepts still rely on the rat model of Passive Heymann Nephritis that derives from an autoimmune response to glomerular megalin, with complement activation and membrane attack complex assembly. Clusterin has been reported as a megalin ligand in immunodeposits, although its role has not been clarified. We studied renal biopsies of 60 MGN patients by immunohistochemistry utilizing antibodies against clusterin, C5b-9, and phosphorylated-protien kinase C (PKC) isoforms (pPKC). In vitro experiments were performed to investigate the role of clusterin during podocyte damage by MGN serum and define clusterin binding to human podocytes, where megalin is known to be absent. Clusterin, C5b-9, and pPKC-alpha/beta showed highly variable glomerular staining, where high clusterin profiles were inversely correlated to C5b-9 and PKC-alpha/beta expression (P=0.029), and co-localized with the low-density lipoprotein receptor (LDL-R). Glomerular clusterin emerged as the single factor influencing proteinuria at multivariate analysis and was associated with a reduction of proteinuria after a follow-up of 1.5 years (-88.1%, P=0.027). Incubation of podocytes with MGN sera determined strong upregulation of pPKC-alpha/beta that was reverted by pre-incubation with clusterin, serum de-complementation, or protein-A treatment. Preliminary in vitro experiments showed podocyte binding of biotinilated clusterin, co-localization with LDL-R and specific binding inhibition with anti-LDL-R antibodies and with specific ligands. These data suggest a central role for glomerular clusterin in MGN as a modulator of inflammation that potentially influences the clinical outcome. Binding of clusterin to the LDL-R might offer an interpretative key for the pathogenesis of MGN in humans.

Adult↗
PubMed2005

Central venous catheter-related complications in children with oncological/hematological diseases: an observational study of 418 devices.

BACKGROUND: The use of indwelling central venous catheters (CVCs) has become commonplace in the management of children undergoing anticancer treatment. Several types of CVC are available, while information on complications observed in children is scarce. We describe the experience of two tertiary care centers in Italy that prospectively followed up three types of CVC used at both institutions over a 30-month period. PATIENTS AND METHODS: Between January 2000 and May 2002, double-lumen (DL) or single-lumen (SL) Hickman-Broviac (HB) catheters, and single-lumen pressure-activated safety valve (PASV) catheters were used and prospectively evaluated. Four types of possible complication were defined a priori: mechanical, thrombotic, malfunctioning and infectious. RESULTS: Four hundred and eighteen CVCs (180 SL-HB, 162 DL-HB and 76 PASV) were inserted in 368 children, for a total of 107 012 catheter days at risk of complication. At least one complication occurred while using 169 of the devices (40%): 46% of the DL-HB, 46% of the PASV and 33% of the SL-HB (P=0.02) catheters. Subjects with hematological malignancies or non-malignant diseases had significantly more complications than those with solid tumors (P <0.0001). Overall, 234 complications were documented: 93 infectious [complication rate per 1000 catheter days at risk (CR)=0.87], 84 malfunctioning (CR=0.78), 48 mechanical (CR=0.45) and nine thrombotic (CR=0.08). SL-HB had statistically fewer infectious complications, while PASV had more mechanical complications. In a multivariate regression model, the most significant risk factors for having a CVC complication were hematological disease [relative risk (RR)=3.0; 95% confidence interval (CI) 1.8-4.8] and age <6 years at CVC insertion (RR=2.5; 95% CI 1.5-4.1). As for the type of CVC, compared with SL-HB, the DL-HB catheter had a statistically significant two-fold increased risk of any complication (RR=2.1; 95% CI 1.2-3.6), while the PASV catheter had a borderline RR of 1.8 (95% CI 1.0-3.6). Analysis by tumor type showed a higher risk of any kind of complication in patients with solid malignancies who had received a DL-HB catheter as compared with an SL-HB catheter (RR=7.2; 95% CI 2.8-18.7). CONCLUSIONS: CVCs may cause complications in up to 40% of patients, with type of CVC, underlying disease and patient age being the three main factors that affect the incidence of CVC-related complications. SL-HB catheters have the best performance.

Antineoplastic Agents↗
PubMed2005

Sequence specific peptidomimetic molecules inhibitors of a protein-protein interaction at the helix 1 level of c-Myc.

Our work is focused in the broad area of strategies and efforts to inhibit protein-protein interactions. The possible strategies in this field are definitely much more varied than in the case of ATP-pocket inhibitors. In our previous work (10), we reported that a retro-inverso (RI) form of Helix1 (H1) of c-Myc, linked to an RI-internalization sequence arising from the third alpha-helix of Antennapedia (Int) was endowed with an antiproliferative and proapoptotic activity toward the cancer cell lines MCF-7 and HCT-116. The activity apparently was dependent upon the presence of the Myc motif. In this work, by ala-scan mapping of the H1 portion of our molecules with D-aa, we found two amino acids necessary for antiproliferative activity: D-Lys in 4 and D-Arg in 5 (numbers refer to L-forms). In the natural hetero-dimer, these two side chains project to the outside of the four alpha-helix bundle. Moreover, we were able to obtain three peptides more active than the original lead. They strongly reduced cell proliferation and survival (RI-Int-VV-H1-E2A,S6A,F8A; RI-Int-VV-H1-S6A,F8A,R11A; RI-Int-VV-H1-S6A,F8A,Q13A): after 8 days at 10 muM total cell number was approximately 1% of the number of cells initially seeded. In these more potent molecules, the ablated side chains project to the inside in the corresponding natural four alpha-helix bundle. In the present work, we also investigated the behavior of our molecules at the biochemical level. Using both a circular dichroism (CD) and a fluorescence anisotropy approach, we noted that side chains projecting at the interior of the four alpha-helix bundle are needed for inducing the partial unfolding of Myc-H2, without an opening of the leucine zipper. Side chains projecting at the outside are not required for this biochemical effect. However, antiproliferative activity had the opposite requirements: side chains projecting at the outside of the bundle were essential, and, on the contrary, ablation of one side chain at a time projecting at the inside increased rather than decreased biological activity. We conclude that our active molecules probably interfere at the level of a protein-protein interaction between Myc-Max and a third protein of the transcription complex. Finally, CD and nuclear magnetic resonance (NMR) data, plus dynamic simulations, suggest a prevalent random coil conformation of the H1 portion of our molecules, at least in diluted solutions. The introduction of a kink (substitution with proline in positions 5 or 7) led to an important reduction of biological activity. We have also synthesized a longer peptido-mimetic molecule (RI-Int-H1-S6A,F8A-loop-H2) with the intent of obtaining a wider zone of interaction and a stronger interference at the level of the higher-order structure (enhanceosome). RI-Int-H1-S6A,F8A-loop-H2 was less active rather than more active in respect to RI-Int-VV-H1-S6A,F8A, apparently because it has a clear bent to form a beta-sheet (CD and NMR data).

Amino Acid Sequence↗
PubMed2005

Ozone air pollution and daily mortality in Genoa, Italy between 1993 and 1996.

The association between ozone (O3) and daily mortality was investigated in Genoa, an Italian city characterized by a Mediterranean climate and a high prevalence of elderly inhabitants. The O3 effect, adjusted for long time trend, seasonality and weather, was assessed using Poisson regression modelling, allowing for overdispersion and autocorrelation, and expressed as mean variation percent of daily mortality per 50 microg/m3 increase (MV). Significant MVs for overall (+4.0%) and cardiovascular (+7.2%) mortality were detected at 1-day lag. The effects were stronger in the warmer season (May-October). Similar estimates were found after restricting the analyses to the elderly (>or=75 years). Furthermore, in this group, higher MVs were observed for total mortality at 2-day lag. A statistically significant synergistic effect between O3 and temperature was observed for cardiovascular mortality, particularly in elderly people, with an evident increase in mortality risk above 26 degrees C (MV +30.0% for the whole population and +40.0% for the elderly, respectively). This investigation highlights the importance of taking local climatic and demographic features into account when comparing different time-series studies, and substantiates the influence of photochemical pollution on mortality trends in small urban areas.

Age Factors↗
PubMed2005

Differences in the proportions of fluoroquinolone-resistant Gram-negative bacteria isolated from bacteraemic children with cancer in two Italian centres.

The proportion of ciprofloxacin-resistant Gram-negative bacteria isolated from the blood of children with cancer (not receiving prophylaxis) was 10% in a paediatric hospital (Genoa) where the use of quinolones was highly restricted, compared with 41% in a department of haematology (Rome) where leukaemic adults, who received fluoroquinolone prophylaxis, were also treated (p < 0.0001). Moreover, simultaneous resistance to ciprofloxacin and ceftazidime, amikacin or imipenem-cilastatin was 11% in Genoa compared with 37% in Rome (p < 0.001). Ciprofloxacin resistance was more frequent in children who shared an environment with adults who were receiving ciprofloxacin prophylaxis.

Amikacin↗
PubMed2003

Differences in the epidemic rise and decrease of prostate cancer among geographical areas in Southern Europe. an analysis of differential trends in incidence and mortality in France, Italy and Spain.

This is a population-based study aimed at evaluating incidence and mortality trends for prostate cancer in France, Italy and Spain, during the prostate-specific antigen (PSA) era, considering elderly people aged 70 years and over and younger adults aged between 40 and 69 years. Trends were estimated by a log-linear Poisson regression model and expressed as an Estimated Annual Percent Change (EAPC). Incidence increased sharply in almost all areas. Spain showed the lowest increases. Incidence started to rise around 1985 in France and after 1990 in Italy and Spain. Mortality increased until the late 1980s in all countries, then declined in France and Italy (-2.5% in 40-69 year age group), but not in Spain. Younger people showed a much higher rise in incidence than the elderly, while mortality decreased mainly in the younger adults. The decrease in mortality was more marked in those areas and the younger age group where the rise in incidence was higher and started earlier, i.e. in France and in younger people, suggesting that the PSA test may have had a positive effect on mortality, although other clinical advances also have to be taken into account.

Adult↗
PubMed2003

Lymphohaematopoietic system cancer incidence in an urban area near a coke oven plant: an ecological investigation.

AIMS: To evaluate the incidence risk of lymphohaematopoietic cancers for the 1986-94 period in Cornigliano, a district of Genoa (Italy), where a coke oven is located a few hundred metres from the residential area. METHODS: The whole of Genoa and one of its 25 districts (Rivarolo) were selected as controls. The trend of risk around the coke oven was evaluated via Stone's method, while the geographic pattern of such risks across the Cornigliano district was evaluated by computing full Bayes estimates of standardised incidence ratio (FBE-SIR). RESULTS: In males, elevated relative risks (RR) were observed for all lymphohaematopoietic cancers (RR 1.7 v Rivarolo and 1.6 v Genoa), for NHL (RR 2.4 v Rivarolo and 1.7 v Genoa), and for leukaemia (RR 2.4 v Rivarolo and 1.9 v Genoa). In females, statistically non-significant RR were observed. In males no excess of risk was found close to the coke oven. In females, a rising risk for NHL was observed approaching the plant, although statistical significance was not reached, while the risk for leukaemia was not evaluable due to the small number of cases. Analysis of the geographic pattern of risk suggested the presence of a cluster of NHL in both sexes in the eastern part of the district, where a foundry had been operational until the early 1980s. A cluster of leukaemia cases was observed in males in a northern part of the area, where no major sources of benzene seemed to be present. CONCLUSIONS: The estimated risks seem to be slightly or not at all related to the distance from the coke oven. The statistically significant higher risks observed in males for NHL and leukaemia, and the clusters of leukaemia in males and of NHL in both sexes deserve further investigations in order to trace the exposures associated with such risks.

Benzene↗
PubMed2001

Intracystic epidermal growth factor level is predictive of breast-cancer risk in women with gross cystic disease of the breast.

Women affected by gross cystic disease of the breast have an increased risk of breast cancer. We report here the incidence of breast cancer by cyst type and intracystic epidermal growth factor (EGF) concentration. Our retrospective study included 504 women who had at least 1 cyst aspiration between 1985 and 1993. Cyst fluids were processed for electrolyte concentration (n = 378), EGF concentration (n = 347) or both (n = 337). Age-standardized incidence ratios (SIRs) were estimated using the population of the Genoa Cancer Registry. A multivariate Poisson regression model was used to estimate relative risks (RRs) when the study groups were compared directly. By June 1999, 19 invasive breast cancers had developed in the cohort of women. The age SIR of breast cancer calculated for the whole cohort was 3.32 (95% confidence interval 2.00-5.18). The ratio was not affected by age and was only moderately increased in women with a positive family history of breast cancer and type I cysts (i.e., those with a Na+/K+ ratio <3). However, it was significantly increased in women with high EGF concentrations. Direct comparisons confirmed that age, cyst type and family history only moderately increased the RR, whereas EGF concentration was a strong predictor of risk. Our results confirm that women affected by palpable cysts have an increased risk of developing breast cancer and suggest that the risk is higher in women with high intracystic EGF concentrations.

Adult↗
PubMed2001

Analysis of 13 (32)P-DNA postlabeling studies on occupational cohorts exposed to air pollution.

Industrial and urban workers may be exposed to significant levels of air pollutants resulting from the incomplete combustion of organic matter. The authors performed a meta-analysis of 13 DNA-adduct studies ((32)P-DNA postlabeling technique) on occupational cohorts exposed to air pollution. The association between levels of DNA adducts and air pollution exposure was significant both in heavily exposed industrial workers and in less severely exposed urban workers. Moreover, in an analysis using the seven studies that reported measuring levels of benzo[a]pyrene (B(a)P), a typical marker of exposure, DNA adduct levels in exposed workers (versus those in referents) were significantly correlated with air levels of B(a)P. The relation between DNA adducts and B(a)P was found to be linear at low doses and sublinear at high doses, indicating that DNA adduct formation tends to reach some kind of saturation point at higher levels of exposure to the chemical mixtures present in fumes. When the authors examined the efficiency of DNA adduct production associated with increasing air pollution exposures, the production of DNA adducts per unit of exposure was significantly decreased at higher B(a)P exposure levels. These findings suggest that linear downward extrapolations based on DNA adduct levels associated with B(a)P concentrations of > or =20 ng/m(3) might be affected by underestimation bias.

Air Pollutants, Occupational↗
PubMed2001

Mortality trend for multiple sclerosis in Italy (1974-1993).

The prevalence of multiple sclerosis (MS) in Italy is one of the highest in Europe, estimated proportions ranging between 32 and 69 cases per 100,000. An update of mortality time trend analyses can help trace a picture of the evolution of the disease and contribute to the interpretation of differences related to latitude and gender. Standardized mortality ratios (SMR) were computed for the 1974-1993 calendar period, using the pooled data set as standard. World population was the standard used to estimate age-adjusted rates for all Italy, while for selected regions the 1991 Italian population was utilized. Time trend analysis was performed using the Poisson regression model and the variation of mortality rates in time was expressed as mean difference per cent per year. Age-adjusted rates per million inhabitants were 4.1 for males and 5.0 for females. Northern Italian regions showed higher MS mortality rates than Central and Southern regions and Sicily, particularly in females; the effect was less evident in Sardinia. Time trend analysis by area showed a mortality decrease in Northern Italy (-1.15%) that reached statistical significance for men. In central regions a slight increase of borderline statistical significance (+1.03%) was observed only in women. while in the South and Sicily a statistically significant increase was seen in both males (+2.14%) and females (+3.09%). The analysis of the time trend for all Italy did not reveal significant variations in male mortality; by contrast, a slight, but statistically significant, increase (+0.88%) was observed in female mortality. Analysis of age-adjusted MS mortality rates in each region suggested the presence of an effect due to latitude. The occurrence of an increasing trend in Southern Italian regions and Sicily deserves further investigation.

Female↗
PubMed2001

Diagnostic value of CYFRA 21-1 tumor marker and CEA in pleural effusion due to mesothelioma.

STUDY OBJECTIVE: The aim of our study was to assess the clinical value of CYFRA 21-1 tumor marker and carcinoembryonic antigen (CEA) as diagnostic tools that are complementary to cytology in the diagnosis of malignant mesotheliomas. PATIENTS: We measured CEA and CYFRA 21-1 in the pleural effusions (PEs) and serum of 106 patients (benign lung disease, 34 patients; bronchogenic and metastatic carcinoma, 40 patients; mesothelioma, 32 patients). METHODS: CEA and CYFRA 21--1 levels were determined by means of two commercial enzyme immunoassays. RESULTS: The cutoff levels of CYFRA 21--1 and CEA in malignant PEs, selected on the basis of the best diagnostic efficacy, were 41.9 ng/mL and 5.0 ng/mL, respectively. In all neoplastic PEs, CYFRA 21--1 and CEA sensitivity was 78% and 30.6%, respectively, with a specificity of 80% and 91%, respectively. The sensitivity of CYFRA 21--1 and CEA in patients with mesothelioma was 87.5% and 3.1%, respectively. The results of the CYFRA 21--1 assay were positive in 17 of 19 cases of mesothelioma (89.5%) with a negative or uncertain cytology. The association of the tumor marker assay and the cytology allowed a correct diagnosis in 30 of 32 cases of mesothelioma (93.7%). CONCLUSION: This study suggests that CYFRA 21--1 would provide a useful parameter for the differential diagnosis between benign and malignant PE from mesothelioma when the result of cytology is negative or uncertain and the clinical context does not allow a more aggressive approach. Moreover, the association of CYFRA 21--1 with CEA could provide details for a differential diagnosis between mesotheliomas and carcinomas. In fact, an elevated CYFRA 21--1 level with a low CEA level is highly suggestive of mesothelioma, whereas high levels of CEA alone or high levels of both the markers suggest a diagnosis of malignant PE, excluding mesothelioma.

Antigens, Neoplasm↗
PubMed2001

HPV16-E6 enhances mitoxantrone sensitivity in a human ovarian cancer line: an isolated instance or a trend?

A cellular isogenic system, in which wt-p53 expression level is challenged through human papilloma virus 16-E6 gene transfection, was previously developed in our laboratory. As an average trend, cancer lines bearing an inactivated p53 have a general tendency toward an increased resistance to chemotherapeutic agents. However, using the above isogenic system, the transfected line (A2780-N9) was found to be more sensitive to taxol than the parental one (A2780-WT). In a NCI meta-analysis study the average trend is that altered p53 status is related to cellular resistance to topoisomerase II inhibitors, while it is irrelevant in determining sensitivity/resistance to mitotic spindle poisons. We report that our E6 transfected line, previously shown to be hypersensitive to taxol, is also clearly hypersensitive to a topoisomerase II inhibitor (mitoxantrone). Differences in cytotoxicity are more evident after a shorter/more intense exposure, than after a milder/longer exposure, being A2780-WT 27-fold more resistant than the transfected clone in the former case. These differences seem to be related to the different activities ("cross-talks") of E6 protein, among which shortening of p53 half-life is only one aspect. After mitoxantrone treatment A2780-N9 cells display also an increased propensity to apoptosis. In addition, a literature survey of E6 effects in transfected cancer cell lines, seems to suggest that chemosensitization to different classes of antineoplastic agents is the rule rather than the exception in these E6-based isogenic systems.

Antineoplastic Agents↗
PubMed2001

Direct in situ PCR allows rapid and sensitive detection of high risk human papillomavirus in cytologic specimens and formalin-fixed paraffin tissues by fluorescent labelling.

We developed a rapid, sensitive and robust high risk human papillomavirus (HR HPV) detection protocol based on direct in situ PCR technology and fluorochrome-modified nucleotides on cytologic specimens (cell smears) and on HPV infected tissues (CIN III). Reproducible results on both cytologic specimens and paraffin-embedded tissues were obtained, providing a powerful tool for clinical investigation on HR HPV infection. Quantitative PCR performed on the same tissue sections adjacent to those used for in situ techniques allowed us to establish the sensitivity of our methods, able to detect rare copies (about 15 in our paraffin-embedded tissues) of HPV.

Female↗
PubMed2000

A retro-inverso peptide homologous to helix 1 of c-Myc is a potent and specific inhibitor of proliferation in different cellular systems.

In 1998 we reported that an L-peptide derived from H1 of c-Myc (Int-H1-S6A,F8A), linked to an internalization sequence from the third a-helix of Antennapedia, was endowed with an antiproliferative and proapoptotic activity toward a human mammary cancer cell line: The activity apparently depends upon the presence of the Myc motif. In the present work we have added new dimensions to our original findings. It is known that short retro-inverso (RI-) peptides can assume a 3D conformation very close to their corresponding L-forms and can be recognized by the same monoclonal antibody. We synthesized a RI-peptide form of our original L-peptide: It was much more resistant to serum peptidases than the original molecule (a half life of days rather than hours); in addition, the RI-form of the original Antennapedia internalization sequence was perfectly capable of carrying a D-peptide into human cells. We have studied three different potentially active peptides. L-peptides: Int-H1wt, Int-H1-S6A,F8A. D-peptides: RI-Int -H1-S6A,F8A. We have also studied three presumed control peptides: Int and RI-Int (no H1 motif), H1-S6A,F8A (no internalization sequence). Both 'active' and 'control' peptides have essentially confirmed our expectations, however, in cells treated with the higher concentration (10 mM) of the control peptide RI-Int, non-Myc related side effects could be detected. In order to investigate whether the antiproliferative activities displayed by some of our molecules were indeed related to an interference with the role of c-Myc (and molecules of the family), we chose an iso-amphipathic modified peptide of the H1 motif, with a proximity coefficient >50% and where the major change was at position 7 (F-->A). From a family of 73 H1 motifs belonging to (H1-Loop-H2) hu man sequences, the smallest evolutionary distance from our reference peptide was observed for the H1 of N-Myc, L-Myc, c-Myc, H1-S6A,F8A of c-Myc, and Max, in that order. Our reference peptide was therefore appropriate as a check of whether we were indeed observing activities related to Myc functions. Both Int-H1isoamph and the corresponding RI-Int-H1isoamph peptide were synthesized and studied. In terms of biological targets, we added to the human mammary cancer line of our previous work (MCF-7 cells) a colon cancer line (HCT-116 cells) and also a system of normal cells: human peripheral blood lymphocytes (PBLs) stimulated with phytohemoagglutinin (PHA). Peptides carrying an iso-amphipathic-modified H1 sequence were always very clearly (3-10 times) less active than the corresponding peptides carrying a conserved "H1 of Myc" motif. This finding was noted in five independent situations (all the cellular models considered at the present time): MCF-7 cells treated with L-peptides; MCF-7 cells treated with RI-peptides; HCT-116 cells treated with L-peptides; PBLs treated with L-peptides; PBLs treated with RI-peptides. Modulation of transcription levels of ornithine decarboxylase (ODC), p53, and glyceraldehyde-3-phosphate dehydrogenase (GAPDH), in PBLs treated with our different molecules, was well compatible with an interference by our active peptides at the level of Myc transcriptional activity. We had already reported a similar observation in MCF-7 cells. On a molar basis, RI-peptides were about 5-10 times more potent and 30-35 times more stable in complete culture medium, than their corresponding L-forms. RI-Int can probably internalize longer peptido-mimetic molecules (for instance molecules mimetic of (H1-Loop-H2), or even more. These possibilities open the way to rodent studies and to more potent/selective Myc inhibitors-two steps closer to a potential drug.

Amino Acid Motifs↗