Cytochrome P450 1B1 polymorphism drives cancer cell stemness and patient outcome in head-and-neck carcinoma

Background

Cytochrome P450 1B1 (CYP1B1) is mostly expressed in tumours and displays unusual properties. Its two polymorphic forms were differently associated with anticancer drug sensitivity. We decipher here the role of this polymorphism in anticancer drug efficacy in vitro, in vivo and in the clinical setting.

Methods

From head-and-neck squamous cell carcinoma cell lines not expressing CYP1B1, we generated isogenic derivatives expressing the two forms. Proliferation, invasiveness, stem cell characteristics, sensitivity to anticancer agents and transcriptome were analysed. Tumour growth and chemosensitivity were studied in vivo. A prospective clinical trial on 121 patients with advanced head-and-neck cancers was conducted, and a validation-retrospective study was conducted.

Results

Cell lines expressing the variant form displayed high rates of in vitro proliferation and invasiveness, stemness features and resistance to DNA-damaging agents. In vivo, tumours expressing the variant CYP1B1 had higher growth rates and were markedly drug-resistant. In the clinical study, overall survival was significantly associated with the genotypes, wild-type patients presenting a longer median survival (13.5 months) than the variant patients (6.3 months) (p = 0.0166).

Conclusions

This frequent CYP1B1 polymorphism is crucial for cancer cell proliferation, migration, resistance to chemotherapy and stemness properties, and strongly influences head-and-neck cancer patients’ survival.

CoDE-seq, an augmented whole-exome sequencing, enables the accurate detection of CNVs and mutations in Mendelian obesity and intellectual disability

Objective

The molecular diagnosis of extreme forms of obesity, in which accurate detection of both copy number variations (CNVs) and point mutations, is crucial for an optimal care of the patients and genetic counseling for their families. Whole-exome sequencing (WES) has benefited considerably this molecular diagnosis, but its poor ability to detect CNVs remains a major limitation. We aimed to develop a method (CoDE-seq) enabling the accurate detection of both CNVs and point mutations in one step.

Methods

CoDE-seq is based on an augmented WES method, using probes distributed uniformly throughout the genome. CoDE-seq was validated in 40 patients for whom chromosomal DNA microarray was available. CNVs and mutations were assessed in 82 children/young adults with suspected Mendelian obesity and/or intellectual disability and in their parents when available (n_total = 145).

Results

CoDE-seq not only detected all of the 97 CNVs identified by chromosomal DNA microarrays but also found 84 additional CNVs, due to a better resolution. When compared to CoDE-seq and chromosomal DNA microarrays, WES failed to detect 37% and 14% of CNVs, respectively. In the 82 patients, a likely molecular diagnosis was achieved in >30% of the patients. Half of the genetic diagnoses were explained by CNVs while the other half by mutations.

Conclusions

CoDE-seq has proven cost-efficient and highly effective as it avoids the sequential genetic screening approaches currently used in clinical practice for the accurate detection of CNVs and point mutations.

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Whole-exome sequencing (WES) poorly detects CNVs.

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Whole-genome sequencing remains expensive and hard to handle in clinical practice.

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CoDE-seq (based on an augmented WES protocol) accurately detect CNVs.

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CoDE-seq is highly effective for the diagnosis of obesity & intellectual disability.

Phenotypical characterization of peanut allergic children with differences in cross-allergy to tree nuts and other legumes

BACKGROUND

Peanut allergy in children is often associated with allergies to tree nuts and/or legumes. The aim of this study was to analyze in cluster a cohort of children allergic to peanuts and assessed for cross-reactivity to nuts and legumes and to identify different phenotypes.

METHODS

We included retrospectively 317 children with peanut allergy evaluated at the Allergy Unit of the Saint Vincent Hospital of Lille in the last 12 years. A complete workup for peanut allergy and nuts and legumes was carried out for each patient. A hierarchical agglomerative clustering method was used to search for clusters of individuals in the evaluated cohort.

RESULTS

Cross-allergy to TN and/or other legumes was identified in 137 patients (43.2%), atopic dermatitis being a major risk factor (adjusted OR = 16 [95% CI: 7.4-37]; p < 0.001). Three phenotypes emerged from cluster analysis. Cluster 1 (72 patients) is characterized by high level of rAra h 2, low threshold reactive doses for peanut and high proportion of asthma; Cluster 2 (93 patients) is characterized by high threshold reactive doses for peanut and the lowest proportion of cross-allergy to TN and/or legumes; Cluster 3 (152 patients) has a high risk of cross-allergy to TN and/or legumes and most patients suffer from eczema.

CONCLUSIONS

The three phenotypes highlighted by this study could be useful to identify children with high risk of cross-allergic reaction to TNs and legumes early after PA diagnosis.

Abstract 2091: Atypical relationship between cytochrome P450 1B1 (CYP1B1) polymorphism and cell proliferation and invasiveness in head-and-neck carcinoma

We have previously shown a close association between a single nucleotide polymorphism (SNP) of cytochrome P450 1B1 (CYP1B1) (V432L, rs1056836) and in vitro sensitivity to several anticancer agents. From squamous cell carcinoma (HNSCC) cell lines not expressing this cytochrome, CAL27 and CAL33, we generated by lentiviral infection isogenic derivatives expressing to similar levels the two variant forms of CYP1B1.

Cell lines re-expressing CYP1B1 had higher proliferation and invasiveness than the original ones, and this was further increased when they expressed the variant form, which were significantly resistant to cisplatin and camptothecin. This was confirmed by in vivo studies in SCID mice: tumors re-expressing CYP1B1 had growth acceleration, especially those expressing the variant form. Treatment by cisplatin, irinotecan and doxorubicin induced regression of tumors obtained from vector-only infected cells, while those obtained from cells re-expressing CYP1B1, especially the variant form, were markedly resistant to all three drugs.

Four proteins representative of epithelial and mesenchymal phenotypes were determined by western blots. In the CAL33 cell line, the expression of E-cadherin and claudin-1 (epithelial markers) was decreased upon re-expression of CYP1B1, whereas the expression of N-cadherin and vimentin (mesenchymal markers) was increased. In the CAL27 cell line, this was the same only for mesenchymal markers. Using the Aldefluor assay kit, a stem cell phenotype was exhibited by the CAL27 line re-expressing the CYP1B1 variant genotype.

In silico studies on the collections of cancer cell lines (NCI-60 and CCLE) confirmed the significant association between CYP1B1 polymorphic status and resistance to DNA-damaging drugs. In addition, the variant genotype was associated to a mesenchymal phenotype defined by significant overexpression of series of 8-12 genes including vimentin and moesin, whereas the common and heterozygous genotypes were associated to an epithelial phenotype defined by significant overexpression of a series of 20-30 genes, including claudins 3, 4 and 7, E-cadherin and EPCAM.

The clinical consequences of the CYP1B1 L432V gene polymorphism were studied in a prospective population of 125 head-and-neck cancer patients (pts) treated in the palliative setting: 48 pts with common homozygous genotype (CH), 40 heterozygotes (HT) and 35 variant homozygous pts (VH). No differences in response rates as a function of the polymorphism were noticed. Overall median survival was significantly worse in VH pts (6.6 months) than in CH (13.2 months), HT falling in between (9.8 months) (p = 0.017).

As a conclusion, CYP1B1 appears to be involved in cell proliferation and invasiveness, these properties being magnified when expressed under its homozygous variant form, which is suggested to be associated to the epithelial-to-mesenchymal transition.

Citation Format: Valérie Le Morvan, Elodie Richard, Maud Cadars, Alban Pasquies, Amélie Lansiaux, Jacques Robert. Atypical relationship between cytochrome P450 1B1 (CYP1B1) polymorphism and cell proliferation and invasiveness in head-and-neck carcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2091.

Human epidermal growth factor receptor 3 in head and neck squamous cell carcinomas

Human epidermal growth factor receptor 3 (HER3) is a member of the human epidermal growth factor receptor (HER) family. The main characteristic of HER3 is that it does not possess tyrosine kinase activity, unlike other HERs. The role of HER3 in tumorigenesis has now been recognized, particularly in head and neck squamous cell carcinomas (HNSCCs). Despite conflicting studies, HER3 was found to be overexpressed in HNSCC samples, and correlates with disease progression and poor survival, especially when it is coexpressed with other HERs. HER3 is a significant factor in HNSCC treatment resistance. Indeed, HER3 is a major mechanism described for cetuximab resistance because of modification of epidermal growth factor receptor (EGFR) internalization and by phosphotidylinositol-3-kinase (PI3K)/AKT signaling pathway activation. HER3 also affects resistance to tyrosine kinase inhibitors (TKIs) and thereby promotes treatment escape and radiotherapy resistance by activation of the survival signaling pathway. To counteract this, pharmacologic inhibitors of HER3 are currently in development and could significantly improve HNSCC treatment. © 2016 Wiley Periodicals, Inc. Head Neck 38: E2412-E2418, 2016.

Synthesis, antitumor activity, and mechanism of action of benzo[b]chromeno[6,5-g][1,8]naphthyridin-7-one analogs of acronycine

A series of 6-methoxy-3,3,14-trimethyl-3,14-dihydro-7H-benzo[b]chromeno[6,5-g][1,8]naphthyridin-7-one (4), 13-aza derivatives of benzo[b]acronycine, the isomeric 5-methoxy-2,2,13-trimethyl-2,13-dihydro-6H-benzo[b]chromeno[7,6-g][1,8]naphthyridin-6-one (5), and related cis-diols mono- and diesters were designed and synthesized. Their in vitro and in vivo biological activities were evaluated. As previously observed in the acronycine series, esters were the most potent derivatives exhibiting submicromolar activities; among them monoesters are particularly active. Racemic diacetate 21 showed a strong activity against KB-3-1 cell lines and was selected for in vivo evaluation and proved to be active, inhibiting tumor growth by more than 80%. After separation of the two enantiomers, compounds 21a and 21b were also evaluated against C38 colon adenocarcinoma; their activities were found to be significantly different.

Activity of the polyamine-vectorized anti-cancer drug F14512 against pediatric glioma and neuroblastoma cell lines

The poor prognosis of children with high-grade glioma (HGG) and high-risk neuroblastoma, despite multidisciplinary therapeutic approaches, demands new treatments for these indications. F14512 is a topoisomerase II inhibitor containing a spermine moiety that facilitates selective uptake by tumor cells via the Polyamine Transport System (PTS) and increases topoisomerase II poisoning. Here, F14512 was evaluated in pediatric HGG and neuroblastoma cell lines. PTS activity and specificity were evaluated using a fluorescent spermine-coupled probe. The cytotoxicity of F14512, alone or in combination with ionizing radiation and chemotherapeutic agents, was investigated in vitro. The antitumor activity of F14512 was assessed in vivo using a liver-metastatic model of neuroblastoma. An active PTS was evidenced in all tested cell lines, providing a specific and rapid transfer of spermine-coupled compounds into cell nuclei. Competition experiments confirmed the essential role of PTS in the cell uptake and cytotoxicity of F14512. This cytotoxicity appeared greater in neuroblastoma cells compared with HGG cells but appeared independent of PTS activity levels. In vivo evaluation confirmed a marked and prolonged antitumoral effect in neuroblastoma cells. The combinations of F14512 with cisplatin and carboplatin were often found to be synergistic, and we demonstrated the significant radiosensitizing potential of F14512 in the MYCN-amplified Kelly cell line. Thus, F14512 appears more effective than etoposide in pediatric tumor cell lines, with greater efficacy in neuroblastoma cells compared with HGG cells. The synergistic effects observed with platinum compounds and the radiosensitizing effect could lead to a clinical development of the drug in pediatric oncology.

Low level of baseline circulating VEGF-A is associated with better outcome in patients with vascular sarcomas receiving sorafenib: an ancillary study from a phase II trial

We have carried out a stratified phase II study of sorafenib (So) in patients with advanced angiosarcoma (n = 32) and epithelioid hemangioendothelioma (n = 13). This report concerns the correlative analysis of the predictive values of circulating pro/anti-angiogenetic biomarkers. Using the ELISA method (R&D Systems), circulating biomarkers (VEGF-A, in picograms per milliliter), thrombospondin-1 (TSP1, in micrograms per milliliter), stem cell factor (SCF, in picograms per milliliter), placental growth factor (PlGF, in picograms per milliliter), VEGF-C (in picograms per milliliter), and E-selectin (in nanograms per milliliter) were measured before So treatment and after 7 days. VEGF-A (mean value 475 vs. 541, p = 0.002), TSP1 (16 vs. 24, p = 0.0002), and PlGF (20.9 vs. 40.7, p = 0.0001) significantly increased during the treatment. Treatment did not affect the levels of SCF, VEGF-C, and E-selectin. Only two biomarkers were associated with better outcome as follows: VEGF-A and PlGF. Best objective response and non-progression at 180 days were associated with low level of VEGF-A at baseline (p = 0.04 and 0.03, respectively). There was a correlation between the circulating level of VEGF-A and time to progression (TTP) (r = -0.47, p = 0.001). Best objective response and non-progression at 180 days were not associated with baseline level of PIGF, but there was a correlation between the circulating level of PIGF at baseline and TTP. Low level of VEGF-A at baseline (<500) was significantly associated with better outcome.

New selective carbonic anhydrase IX inhibitors: synthesis and pharmacological evaluation of diarylpyrazole-benzenesulfonamides

Carbonic anhydrase (CA) IX expression is increased upon hypoxia and has been proposed as a therapeutic target since it has been associated with poor prognosis, tumor progression and pH regulation. We report the synthesis and the pharmacological evaluation of a new class of human carbonic anhydrase (hCA) inhibitors, 4-(5-aryl-2-hydroxymethyl-pyrazol-1-yl)-benzenesulfonamides. A molecular modeling study was conducted in order to simulate the binding mode of this new family of enzyme inhibitors within the active site of hCA IX. Pharmacological studies revealed high hCA IX inhibitory potency in the parameters nanomolar range. This study showed that the position of sulfonamide group in meta of the 1-phenylpyrazole increase a selectivity hCA IX versus hCA II of our compounds. An in vitro antiproliferative screening has been performed on the breast cancer MDA-MB-231 cell using doxorubicin as cytotoxic agent and in presence of selected CA IX inhibitor. The results shown that the cytotoxic efficiency of doxorubicin in an hypoxic environment, expressed in IC50 value, is restored at 20% level with 1μM CA IX inhibitor.

Synthesis, antiproliferative activity and tubulin targeting effect of acridinone and dioxophenothiazine derivatives

The synthesis of new acridinone and dioxophenothiazine derivatives along with their tubulin polymerization inhibitory and antiproliferative activities is reported. The analysis of correlation for cytotoxic and antitubulin potential of tested compounds showed that 4-methoxyphenylethyl derivatives 18a and 19a were highly cytotoxic but were regarded to have no significant antitubulin activity. However, the introduction of a 3-hydroxy substituent leading to compounds 18e and 19e, strongly increased the antitubulin potential but was associated with a loss of the antiproliferative activity. Modeling studies, topoisomerase inhibition assays and cell cycle analysis have been performed to better investigate the mechanism of action of such compounds.

Dual inhibition of MAGL and type II topoisomerase by N-phenylmaleimides as a potential strategy to reduce neuroblastoma cell growth

The endocannabinoid system is implicated in numerous physiopathological processes while more and more pieces of evidence wave the link between this complex machinery and cancer related phenomenon. In these lines, we confirmed the effects of 2-arachidonoylglycerol (2-AG), the main endocannabinoid, on neuroblastoma cells proliferation in vitro, and proved that some N-phenylmaleimide compounds that were previously shown as MAGL inhibitors can also inhibit type 2 topoisomerase. We also shed light on their antiproliferative effects on a neuroblastoma cell line. In order to establish a link between MAGL inhibition, topoisomerase inhibition and the effects on N1E-115 cells, we tested combinations of maleimides or known endocannabinoid metabolism inhibitors and 2-AG, the major MAGL substrate, on N1E-115 cells. However, none of the inhibitors tested, except the carbamate CAY10499, managed to increase 2-AG's effects. Even the MAGL reference inhibitor JZL184 failed to induce a stronger inhibition of proliferation.

Mechanisms underlying resistance to cetuximab in the HNSCC cell line: role of AKT inhibition in bypassing this resistance

EGFR is frequently overexpressed in head and neck squamous cell cancer (HNSCC). Cetuximab is a monoclonal antibody designed to interact with EGFR, block its activation, reduce the downstream signaling pathways and induce EGFR internalization. This study aims to investigate the role of the EGFR signaling pathway and EGFR internalization in a cetuximab-resistant cell line and to propose a new therapeutic strategy to optimize treatment of HNSCC. The HNSCC cell line, CAL33 was sensitive to gefitinib but resistant to cetuximab. Cetuximab induces an unexpected EGFR phosphorylation in CAL33 cells similarly to EGF but this EGFR activation does not trigger EGFR internalization/degradation, the process currently implicated in the response to cetuximab. Cetuximab inhibits ERK and AKT phosphorylation in cetuximab-sensitive A431 cells, whereas the level of AKT phosphorylation is unmodified in cetuximab-resistant cells. Interestingly, CAL33 cells harbor a PIK3CA mutation. The treatment of CAL33 cells with PI3K inhibitor and cetuximab restores the inhibition of AKT phosphorylation and induces growth inhibition. Our results indicate that EGFR internalization is impaired by cetuximab treatment in CAL33 cells and that the AKT pathway is a central element in cetuximab resistance. The combination of cetuximab with a PI3K inhibitor could be a good therapeutic option in PIK3CA-mutated HNSCC.

Design, synthesis, and DNA-binding of N-alkyl(anilino)quinazoline derivatives

New N-alkylanilinoquinazoline derivatives 5, 12, 20, and 22 have been prepared from 4-chloro-6,7-dimethoxyquinazoline 3, 4-chloro-6,7-methylenedioxyquinazoline 19, and commercially available anilines. Differents classes of compounds substituted by an aryloxygroup (6a-c, 16a,b, and 17a,b), (aminophenyl)ureas (12a,b and 13a-f), anilines (4a-m, 20a,b), N-alkyl(aniline) (5a-m, 21a,b, 22a,d), and N-aminoalkyl(aniline) (22e-g) have been synthesized. These molecules were evaluated for their cytotoxic activities and as potential DNA intercalating agents. We studied the strength and mode of binding to DNA of these molecules by DNA melting temperature measurements, fluorescence emission, and circular dichroism. The results of various spectral and gel electrophoresis techniques obtained with the different compounds, in particular compounds 5g and 22f, revealed significant DNA interaction. These experiments confirm that the N-aminoalkyl(anilino)-6,7-dimethoxyquinazoline nucleus is an efficient pharmacophore to trigger binding to DNA, via an intercalative binding process.

Factors for hematopoietic toxicity of carboplatin: refining the targeting of carboplatin systemic exposure

PURPOSE

Area under the curve (AUC) dosing is routinely carried out for carboplatin, but the chosen target AUC values remain largely empirical. This multicenter pharmacokinetic-pharmacodynamic (PK-PD) study was performed to determine the covariates involved in the interindividual variability of carboplatin hematotoxicity that should be considered when choosing individual target AUCs.

PATIENTS AND METHODS

Three hundred eighty-three patients received carboplatin as part of established regimens. A semi-physiologic population PK-PD model was applied to describe separately the time course of absolute neutrophil and platelet counts using NONMEM software. The plasma ultrafiltrable carboplatin concentration (C(Carbo)) was assumed to inhibit the proliferation of blood cell precursors through a linear model: drug effect = slope × C(Carbo). The slope corresponds to the patients' sensitivity to carboplatin hematotoxicity. The relationships between the patients' sensitivity to the neutropenic or thrombopenic effects of carboplatin and various covariates, including associated chemotherapies, demographic, biologic, and pharmacogenetic data, were studied.

RESULTS

The sensitivity of carboplatin-induced thrombocytopenia decreased in the case of concomitant paclitaxel chemotherapy (slope decreased by 24%), whereas it increased with coadministration of etoposide and gemcitabine (slope increased by 45% and 133%, respectively). For neutropenia, the sensitivity increased when carboplatin was combined with other cytotoxics (slope increased by 76%).

CONCLUSION

This study provides useful information to clinicians to better estimate the hematopoietic toxicity of carboplatin and thus choose more rationally carboplatin target AUCs as a function of pretreatment or concomitantly administered chemotherapies. For example, an AUC of 5 mg/mL · min is associated with a risk of grade 3 or 4 thrombocytopenia of 2% in combination with paclitaxel versus 38% with gemcitabine in a non-pretreated patient.

Montmorillonite K-10 catalyzed cyclization of N-ethoxycarbonyl-N'-arylguanidines: access to pyrimido[4,5-c]carbazole and pyrimido[5,4-b]indole derivatives

Two new heterocycles, pyrimido[4,5-c]carbazole and pyrimido[5,4-b]indole, were prepared in three steps from 3-aminocarbazole and 3-aminoindole, respectively. The key Friedel-Crafts intramolecular cyclization was realized under microwave irradiation using montmorillonite K-10 clay as a catalyst. The pyrimido[4,5-c]carbazole derivative shows significant micromolar IC(50) against cancer cell lines. Unlike similar carbazole and indolocarbazole compounds, the molecule does not interfere with topoisomerase activity.

Differential apoptosis-like cell death in amastigote and trypomastigote forms from Trypanosoma cruzi-infected heart cells in vitro

Apoptosis, type-I of programmed cell death (PCD-I), is not restricted to multicellular organisms since many apoptotic features have been described in different trypanosomatids, including Trypanosoma cruzi. Our present aim was to monitor, by different morphological markers, the occurrence of apoptosis-like death in amastigotes and trypomastigotes of T.cruzi (Y strain) during the infection of heart culture cells. We documented the differential occurrence of PCD-I in amastigotes and trypomastigotes, with distinct death rates noticed between these two parasite-distinct forms. Fluorescence microscopy and flow cytometry analysis using different hall markers of apoptosis (phosphatidylserine exposure, collapse of mitochondrial membrane potential and DNA fragmentation) showed that amastigotes present higher levels of apoptosis-like cell death as compared to trypomastigotes. It is possible that the higher levels of PCD-I in these highly multiplicative forms may contribute to the control of the parasite burden within the host cells. On the other hand, the apoptosis-like occurrence in the infective but non-proliferative stage of the parasite (trypomastigotes) may play a role in parasite evasion mechanisms as suggested for other parasites.

A universal formula based on cystatin C to perform individual dosing of carboplatin in normal weight, underweight, and obese patients

2527

Background: It has recently been shown that it is possible to improve the prediction of carboplatin clearance by adding plasma cystatin C level (cysC), an endogenous marker of glomerular filtration rate, to the other patient characteristics routinely used for carboplatin individual dosing, namely serum creatinine (Scr), body weight (BW), age, and sex. This multi-center pharmacokinetic study was performed to evaluate prospectively the benefit of using cysC for carboplatin individual dosing. Methods: The 357 patients included in the study were receiving carboplatin as part of established protocols. A population pharmacokinetic analysis was performed using the NONMEM program. Seven covariates were studied: Scr, cysC, age, sex, BW, ideal body weight, and lean body mass. Results: The best covariate equation was: carboplatin clearance (mL/min) = 105. (Scr/75)-0.433. (cysC/1.00)-0.290 . (BW/65)+0.547 . (age/56)-0.351 . 0.855sex, with Scr in μmol/L, cysC in mg/L, BW in kg, age in years, and sex = 0 for male. Using an alternative weight descriptor (ideal body weight or lean body mass) did not improve the prediction. This final covariate model was validated by bootstrap analysis. The bias (mean percentage error) and imprecision (mean absolute percentage error) were +2% and 15% respectively on the total population, and were of a similar magnitude in each of the three subgroups of patients defined according to their body mass index. Conclusions: For the first time, a unique formula is proposed for carboplatin individual dosing to patients which is shown to be equally valid for underweight, normal weight, and obese patients.

No significant financial relationships to disclose.

Biological and clinical prognostic factors in patients with advanced non-small-cell cancer (NSCLC) treated by erlotinib: Preliminary results of the ERMETIC cohort

8079

Background: Although it has been suggested that results of EGFR-IHC, EGFR-FISH and EGFR and KRAS mutations are predictive of EGFR-TKIs efficacy, they are not used in clinical practice. ERMETIC is a French NCI granted prospective study aiming to facilitate implementation of these biomarkers in France. Methods: After a preliminary phase of validation in 16 French centers, these biomarkers were studied in available tumor specimens collected from all consecutive NSCLC patients (pts) treated by erlotinib, for the first time. Patients were followed-up until progression or death. Demographic, clinical, pathological characteristics and biomarkers were studied by Cox model as predictors of progression free survival (PFS) and overall survival (OS). Results: 493 of the 530 enrolled pts between 02/07 and 03/08 are included in this analysis, among whom at least 357 (72%) tumor specimens were collected. 88% were Caucasians, 32% females; median age was 62 (33–93); 15% were never smoker, 67% former and 15% active. 18% were PS0, 51% PS1 and 31% PS2–3. 92% pts were metastatic and 66% had adenocarcinoma (ADC). Erlotinib (150 mg in 98% of pts) was given as first-, second- and third-or-more-line in 10, 45, 42% of pts, respectively. 94% of pts had received previous platin-based chemotherapy. With a 11.5 months (mo.) median of follow-up, PFS was 2.4 mo. and OS 5.6 mo., with a 30% 1-year OS. Clinical factors independently associated with shorter OS were: PS1 and PS2–3 (HR=1.79 and 4.3, p<.0001); histology other than ADC and squamous cell (HR=1.44 and 1.03, p=.05); 2 sites of metastasis and more (HR=1.60 and 1.82, p<.0001) and former and active smoking (HR=1.49 and 2.12, p=.002). In multivariate analysis, line of treatment was not prognostic. Conclusions: The study confirmed in a large cohort of advanced NSCLC treated by erlotinib the independent value of several prognostic factors. Prognostic values of EGFR-IHC, EGFR-FISH and EGFR and KRAS mutations will be reported at the meeting.

[Table: see text]

Synthesis and antitumoral activity of novel thiazolobenzotriazole, thiazoloindolo[3,2-c]quinoline and quinolinoquinoline derivatives

The biological evaluation of some novel thiazoloindolo[3,2-c]quinoline, 8-substituted-11H-indolo[3,2-c]quinolines is described. These compounds were obtained via Graebe-Ullmann thermal cyclization from appropriated N-arylated benzotriazoles. 7H-4,7-Diaza-benzo[de]anthracene, a reaction by-product structurally closed to the pyridoacridine skeleton was also identified. All thiazolobenzotriazole intermediates were tested in vitro for their capacity to inhibit the growth of two breast cancer cell lines, MCF-7 and MDA-MB-231. In parallel, the newly synthesized skeletons were evaluated for DNA interaction, topoisomerases' inhibition, and cytotoxicity against HL60 and HL60/MX2 human leukemia cells. Most compounds showed a potent growth inhibitory effect on all the tested cell lines, with IC(50) in the muM range.

Design of DNA minor groove binding diamidines that recognize GC base pair sequences: a dimeric-hinge interaction motif

The classical model of DNA minor groove binding compounds is that they should have a crescent shape that closely fits the helical twist of the groove. Several compounds with relatively linear shape and large dihedral twist, however, have been found recently to bind strongly to the minor groove. These observations raise the question of how far the curvature requirement could be relaxed. As an initial step in experimental analysis of this question, a linear triphenyl diamidine, DB1111, and a series of nitrogen tricyclic analogues were prepared. The goal with the heterocycles is to design GC binding selectivity into heterocyclic compounds that can get into cells and exert biological effects. The compounds have a zero radius of curvature from amidine carbon to amidine carbon but a significant dihedral twist across the tricyclic and amidine-ring junctions. They would not be expected to bind well to the DNA minor groove by shape-matching criteria. Detailed DNase I footprinting studies of the sequence specificity of this set of diamidines indicated that a pyrimidine heterocyclic derivative, DB1242, binds specifically to a GC-rich sequence, -GCTCG-. It binds to the GC sequence more strongly than to the usual AT recognition sequences for curved minor groove agents. Other similar derivatives did not exhibit the GC specificity. Biosensor-surface plasmon resonance and isothermal titration calorimetry experiments indicate that DB1242 binds to the GC sequence as a highly cooperative stacked dimer. Circular dichroism results indicate that the compound binds in the minor groove. Molecular modeling studies support a minor groove complex and provide an inter-compound and compound-DNA hydrogen-bonding rational for the unusual GC binding specificity and the requirement for a pyrimidine heterocycle. This compound represents a new direction in the development of DNA sequence-specific agents, and it is the first non-polyamide, synthetic compound to specifically recognize a DNA sequence with a majority of GC base pairs.

Novel Stable Camptothecin Derivatives Replacing the E-Ring Lactone by a Ketone Function Are Potent Inhibitors of Topoisomerase I and Promising Antitumor Drugs

The E-ring lactone is the Achilles' heel of camptothecin derivatives: although it is considered necessary for the inhibition of the enzyme topoisomerase I (topo1), the opening of the lactone into a carboxylate abolishes the generation of topo1-mediated DNA breaks. S38809 is a novel camptothecin analog with a stable 5-membered E-ring ketone; therefore, it lacks the lactone function. DNA relaxation and cleavage assays revealed that S38809 functions as a typical topo1 poison by stimulating DNA cleavage at T downward arrow G sites. The activity was strongly dependent on the stereochemistry of the C-7 carbon atom that bears the hydroxy group. S38809 proved to be a potent cytotoxic agent, with a mean IC50 of 5.4 nM versus 11.6 nM for topotecan and 3.3 nM for SN38 (the active metabolite of irinotecan) on a panel of 31 human tumor cell lines. The cytotoxicity of S38809 and its ability to stabilize cleavable complexes was considerably reduced in camptothecin-resistant cells that express a mutated topo1, confirming that topo1 is its primary target. Cell death induced by topo1 poisoning requires the conversion of DNA single-strand breaks into double-strand breaks that can be detected by the formation of phosphorylated histone H2AX. In HCT116 cells, topotecan, SN38, and S38809 induced histone H2AX phosphorylation in S phase of the cell cycle, with S38809 being as potent as SN38 and 5-fold more potent than topotecan. In vivo, S38809 showed a marked antitumor activity against HCT116 xenografts. These findings open a new route for improving the pharmacological properties of camptothecin derivatives.

[Pemetrexed: from preclinic to clinic]

The pemetrexed (Alimta) is a new generation antifolate prescribed in the treatment of mesothelioma in association with cisplatin and in the 2nd line treatment of locally advanced or metastatic non-small lung cancer. Pemetrexed is an original molecule, different from the other antifolates. On the opposite methotrexate, pemetrexed inhibits several enzymes involved in the synthesis of purines and pyrimidines, in particular thymidylate synthase, dihydrofolate reductase, glycinamide ribonucleotide formyltransferase and 5-aminoimidazole-4-carboxamide ribonucleotide formyltransferase. Pemetrexed is transported in cells by three receptors, which make easier its cellular penetration. On the other hand, the polyglutamation of the product by the folylpolyglutamate synthetase increases considerably its activity notably towards the thymidylate synthase. Finally, unlike methotrexate, pemetrexed presents an atypical effect on cellular synchronisation. The wide spectre of activity of pemetrexed confers it a therapeutic advantage with regard to the other antifolates specific of one or other one enzymes. The clinical results show an anti-tumoral activity against non-small lung cancer and in mesothelioma and recently towards other solid tumours, in particular in head an neck, colon and mammary cancers.

[Gemcitabine: from preclinic to clinic passing by pharmacokinetics]

Gemcitabine or Gemzar forms part of the class of the anti-cancer drugs antimetabolites. Gemcitabine is a structural analogue of the deoxycytidine with 2 fluorine atoms. There is a strong analogy between gemcitabine and cytosine arabinoside (Aracytine or Depocyt), at the same time structural, mechanistic and metabolic. However, if the intracellular derivatives triphosphate of gemcitabine seem more stable than those of the cytarabine, the two molecules move away from share their therapeutic activity. Indeed, if the cytosine arabinoside finds its place in the treatment of hematologic diseases, myeloblastic or lymphoblastic acute leukaemia and in acute myeloid leukaemias and myelodysplasy, gemcitabine sees its indications in the treatment of solid tumours such as non small cell lung cancer, adenocarcinoma of the pancreas, cancer of the bladder and metastatic breast cancer.

Chiral capillary electrophoretic determination of the enantiomeric purity of homocamptothecin derivatives, promising antitumor topoisomerase I inhibitors, using highly sulfated CDs and fluorescence detection

EKC methods for the enantiomeric resolution of homocamptothecin derivatives, potent anticancer agents targeting DNA topoisomerase I selected for clinical trials, were developed using highly sulfated beta-CD as chiral selectors at acidic pH. Optimal electrophoretic conditions, with migration times under 15 min, were as follows: for the neutral homocamptothecin analog 1, a BGE of 75 mM phosphate buffer pH 2.5 (H(3)PO(4) + triethanolamine)/ACN - 95/5 v/v, with 7.5% w/v highly S-beta-CD, an applied field of 0.2 kV/cm and a fused capillary temperature control of 30 +/- 0.1 degrees C (typical current approximately 175 microA); for the cationic homocamptothecin 2, a BGE of 25 mM phosphate buffer pH 2.5 (H(3)PO(4) + TEA)/ACN - 90/10 v/v, with 2.5% w/v highly S-beta-CD, an applied field of 0.15 kV/cm and a fused capillary temperature control of 25 +/- 0.1 degrees C (typical current approximately 45 muA), and both are validated. The best results in terms of LOQ were obtained by EC with fluorescence detection: 10 ng/mL and 20 ng/mL for 1 and 2, respectively (LOQ divided by 150 for 1 and 5 for 2 with respect to UV), thus making this method particularly convenient for enantiomeric purity determination of galenic forms. UV detection appears to be an alternative to fluorescence for the analysis of the main component either for the control of galenic forms or for therapeutic adaptation. Moreover, this method exhibits better performances than HPLC.

Amino- and glycoconjugates of pyrido[4,3,2-kl]acridine. Synthesis, antitumor activity, and DNA binding

A series of amino- and glycoconjugates of pyrido[4,3,2-kl]acridine and pyrido[4,3,2-kl]acridin-4-one have been prepared. The most active molecules, the amino conjugates 7 and 11, display a cytostatic activity against HT-29 cancer cells at micromolar concentration. This activity correlates well with a strong DNA binding. The molecules, amino or glycoconjugates, bind DNA by intercalation, the amino or glyco substituent being located in one groove. None of the molecules inhibits topoisomerase activity.

Generation of Replication-Dependent Double-Strand Breaks by the Novel N2-G-Alkylator S23906-1

S23906-1, a new DNA alkylating agent that reacts with the exocyclic 2-NH2 group of guanine residues yielding monofunctional adducts, is currently under clinical evaluation in phase I trials. To investigate the mechanism of action of S23906-1, we compared parental KB-3-1 cells and KB/S23-500 cells that are 15-fold resistant to S23906-1. Cell death induced by 1 micromol/L S23906-1 in KB-3-1 cells was associated with their irreversible arrest in the G2-M phases of the cell cycle followed by apoptosis, whereas a proportion of the resistant KB/S23-500 cells were able to exit from the G2 arrest and divide, leading to a significantly lower rate of apoptosis. The attenuated apoptotic response was associated with decreased Chk2 protein phosphorylation, indicating that the DNA damage signaling pathways are more potently activated in the sensitive cells. However, similar rates of adduct formation and repair were measured in both cell lines. Exposure to S23906-1 induced a higher formation of DNA breaks, measured by the comet assay, in sensitive cells. In agreement, a histone H2AX phosphorylation assay revealed that S23906-1 induced double-strand breaks (DSB) in a dose- and time-dependent manner and that these were more persistent in the parental cells. These DSBs were found mainly in S-phase cells and inhibited by aphidicolin, suggesting that they are DNA replication-mediated DSBs. These results suggest that secondary DNA lesions play an important role in the cytotoxicity of this compound and make histone H2AX phosphorylation an attractive marker for monitoring the efficacy of S23906-1.