Vaccine antibodies against a synthetic epidermal growth factor variant enhance the antitumor effects of inhibitors targeting the MAPK/ERK and PI3K/Akt pathways.

BACKGROUND: The EGFR pathway is involved in intrinsic and acquired resistance to a wide variety of targeted therapies in cancer. Vaccination represents an alternative to the administration of anti-EGFR monoclonal antibodies, such as cetuximab or panitumumab. Here, we tested if anti-EGF antibodies generated by vaccination (anti-EGF VacAbs) could potentiate the activity of drugs targeting the ERK/MAPK and PI3K/Akt pathways. METHODS: Non-small cell lung cancer (NSCLC), colorectal cancer (CRC) and melanoma cell lines harboring KRAS, NRAS, BRAF and PIK3CA mutations were used. Anti-EGF VacAbs were obtained by immunizing rabbits with a fusion protein containing a synthetic, highly mutated variant of human EGF. Cell viability was determined by MTT, total and phosphorylated proteins by Western blotting, cell cycle distribution and cell death by flow cytometry and emergence of resistance by microscopic examination in low density cultures. RESULTS: Anti-EGF VacAbs potentiated the antiproliferative effects of MEK, KRAS G12C, BRAF, PI3K and Akt inhibitors in KRAS, NRAS, BRAF and PIK3CA mutant cells and delayed the appearance of resistant clones in vitro. The effects of anti-EGF VacAbs were comparable or superior to those of panitumumab and cetuximab. The combination of anti-EGF VacAbs with the targeted inhibitors effectively suppressed EGFR downstream pathways and sera from patients immunized with an anti-EGF vaccine also blocked activation of EGFR effectors. CONCLUSIONS: Anti-EGF VacAbs enhance the antiproliferative effects of drugs targeting the ERK/MAPK and PIK3CA/Akt pathways. Our data provide a rationale for clinical trials testing anti-EGF vaccination combined with inhibitors selected according to the patient's genetic profile.

Defining Optimal Conditions for Tumor Extracellular Vesicle DNA Extraction for Mutation Profiling.

(1) Background: Extracellular vesicles (EVs) have emerged as crucial players in the communication between cells in both physiological and pathological scenarios. The functions of EVs are strongly determined by their molecular content, which includes all bioactive molecules, such as proteins, lipids, RNA, and, as more recently described, double-stranded DNA. It has been shown that in oncological settings DNA associated with EVs (EV-DNA) is representative of the genome of parental cells and that it reflects the mutational status of the tumor, gaining much attention as a promising source of biomarker mutant DNA. However, one of the challenges in studies of EV-DNA is the lack of standardization of protocols for the DNA extraction from EVs, as well as ways to assess quality control, which hinders its future implementation in clinics. (2) Methods: We performed a comprehensive comparison of commonly used approaches for EV-DNA extraction by assessing DNA quantity, quality, and suitability for downstream analyses. (3) Results: We here established strategic points to consider for EV-DNA preparation for mutational analyses, including qPCR and NGS. (4) Conclusions: We put in place a workflow that can be applied for the detection of clinically relevant mutations in the EV-DNA of cancer patients.

Comprehensive cross-platform comparison of methods for non-invasive EGFR mutation testing: results of the RING observational trial.

Several platforms for noninvasive EGFR testing are currently used in the clinical setting with sensitivities ranging from 30% to 100%. Prospective studies evaluating agreement and sources for discordant results remain lacking. Herein, seven methodologies including two next-generation sequencing (NGS)-based methods, three high-sensitivity PCR-based platforms, and two FDA-approved methods were compared using 72 plasma samples, from EGFR-mutant non-small-cell lung cancer (NSCLC) patients progressing on a first-line tyrosine kinase inhibitor (TKI). NGS platforms as well as high-sensitivity PCR-based methodologies showed excellent agreement for EGFR-sensitizing mutations (K = 0.80-0.89) and substantial agreement for T790M testing (K = 0.77 and 0.68, respectively). Mutant allele frequencies (MAFs) obtained by different quantitative methods showed an excellent reproducibility (intraclass correlation coefficients 0.86-0.98). Among other technical factors, discordant calls mostly occurred at mutant allele frequencies (MAFs) ≤ 0.5%. Agreement significantly improved when discarding samples with MAF ≤ 0.5%. EGFR mutations were detected at significantly lower MAFs in patients with brain metastases, suggesting that these patients risk for a false-positive result. Our results support the use of liquid biopsies for noninvasive EGFR testing and highlight the need to systematically report MAFs.

Detection of somatic mutations in peritoneal lavages and plasma of endometrial cancer patients: A proof-of-concept study.

Endometrial cancer (EC) is the most common gynecologic malignancy in developed countries. Although most patients are diagnosed at early stages, 15-20% will relapse despite local treatment. Presently, there are no reliable markers to identify patients with worse outcomes who may benefit from adjuvant treatments, such as chemotherapy, and liquid biopsies may be of use in this setting. Peritoneal lavages are systematically performed during endometrial surgery but little data are available about their potential as liquid biopsies. We analyzed KRAS and PIK3CA mutations in paired surgical biopsies, blood and cytology-negative peritoneal lavages in a cohort of 50 EC patients. Surgical biopsies were submitted to next-generation sequencing (NGS) while circulating-free DNA (cfDNA) purified from plasma and peritoneal lavages was analyzed for KRAS and PIK3CA hotspot mutations using a sensitive quantitative polymerase chain reaction (PCR) assay. NGS of biopsies revealed KRAS, PIK3CA or concomitant KRAS + PIK3CA mutations in 33/50 (66%) EC patients. Of those, 19 cases carried hotspot mutations. Quantitative PCR revealed KRAS and/or PIK3CA mutations in the lavages of 9/19 (47.4%) hotspot EC patients. In contrast, only 2/19 (10.5%) blood samples from hotspot EC patients were positive. Mutations found in cfDNA consistently matched those in paired biopsies. One of the two patients positive in plasma and lavage died in less than 6 months. In conclusion, mutational analysis in peritoneal lavages and blood from early stage EC is feasible. Further studies are warranted to determine if it might help to identify patients with worse prognosis. Human genes discussed: KRAS, KRAS proto-oncogene, GTPase; PIK3CA, phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha.

Evolution and Clinical Impact of EGFR Mutations in Circulating Free DNA in the BELIEF Trial.

INTRODUCTION: Longitudinal evaluation of mutations in blood samples was a prespecified secondary objective in the BELIEF trial of erlotinib and bevacizumab in advanced EGFR-positive NSCLC. Here, we report the testing results and explore the correlation of EGFR status in blood with clinical outcomes. METHODS: Blood samples were prospectively collected from patients at baseline, at response evaluation, and at progression and sent to a central laboratory. Circulating free DNA was purified and EGFR mutations were analyzed with a validated real-time quantitative polymerase chain reaction assay. RESULTS: EGFR exon 19/21 mutations were detected in 55 of 91 baseline blood samples (60.4%) and correlated with a significantly worse progression-free survival: 11.4 months (95% confidence interval [CI]: 9.0-14.8 mo) for the patients who were positive versus 22.9 months (95% CI: 9.5-33.9 mo) for those who were negative (log-rank p = 0.0020). Among the 74 samples at response, exon 19/21 mutations were detected only in three samples (4.1%). In contrast, 29 of 58 patients (50.0%) were exon 19/21 positive at progression and showed a significantly worse median overall survival of 21.7 months (95% CI: 17.0-30.9 mo) compared with 37.4 months (95% CI: 22.6-53.1 mo) for those who were negative (log-rank p = 0.011). Blood samples at the three time points were available for 48 patients. Of those, among 14 exon 19/21 EGFR-negative at presentation, 13 (93%) were persistently negative for the sensitizing mutations after progression and the p.T790M could only be detected in the blood of two patients. CONCLUSIONS: Longitudinal testing of EGFR mutations in blood can offer valuable clinical information. In patients of the BELIEF study, detection of EGFR mutations in circulating free DNA at presentation was associated with shorter progression-free survival, whereas positivity at progression correlated with shorter overall survival. Finally, patients negative in blood at presentation were almost invariably negative at relapse.

Prospective detection of mutations in cerebrospinal fluid, pleural effusion, and ascites of advanced cancer patients to guide treatment decisions.

Many advanced cases of cancer show central nervous system, pleural, or peritoneal involvement. In this study, we prospectively analyzed if cerebrospinal fluid (CSF), pleural effusion (PE), and/or ascites (ASC) can be used to detect driver mutations and guide treatment decisions. We collected 42 CSF, PE, and ASC samples from advanced non-small-cell lung cancer and melanoma patients. Cell-free DNA (cfDNA) was purified and driver mutations analyzed and quantified by PNA-Q-PCR or next-generation sequencing. All 42 fluid samples were evaluable; clinically relevant mutations were detected in 41 (97.6%). Twenty-three fluids had paired blood samples, 22 were mutation positive in fluid but only 14 in blood, and the abundance of the mutant alleles was significantly higher in fluids. Of the 34 fluids obtained at progression to different therapies, EGFR resistance mutations were detected in nine and ALK acquired mutations in two. The results of testing of CSF, PE, and ASC were used to guide treatment decisions, such as initiation of osimertinib treatment or selection of specific ALK tyrosine-kinase inhibitors. In conclusion, fluids close to metastatic sites are superior to blood for the detection of relevant mutations and can offer valuable clinical information, particularly in patients progressing to targeted therapies.

Prospective analysis of liquid biopsies of advanced non-small cell lung cancer patients after progression to targeted therapies using GeneReader NGS platform.

BACKGROUND: In a significant percentage of advanced non-small cell lung cancer (NSCLC) patients, tumor tissue is unavailable or insufficient for genetic analyses at time to progression. We prospectively analyzed the appearance of genetic alterations associated with resistance in liquid biopsies of advanced NSCLC patients progressing to targeted therapies using the NGS platform. METHODS: A total of 24 NSCLC patients were included in the study, 22 progressing to tyrosine kinase inhibitors and two to other treatments. Liquid biopsies samples were obtained and analyzed using the GeneReadTM QIAact Lung DNA UMI Panel, designed to enrich specific target regions and containing 550 variant positions in 19 selected genes frequently altered in lung cancer tumors. Previously, a retrospective validation of the panel was performed in clinical samples. RESULTS: Of the 21 patients progressing to tyrosine kinase inhibitors with valid results in liquid biopsy, NGS analysis identified a potential mechanism of resistance in 12 (57%). The most common were acquired mutations in ALK and EGFR, which appeared in 8/21 patients (38%), followed by amplifications in 5/21 patients (24%), and KRAS mutations in one patient (5%). Loss of the p.T790M was also identified in two patients progressing to osimertinib. Three of the 21 (14%) patients presented two or more concomitant alterations associated with resistance. Finally, an EGFR amplification was found in the only patient progressing to immunotherapy included in the study. CONCLUSIONS: NGS analysis in liquid biopsies of patients progressing to targeted therapies using the GeneReader platform is feasible and can help the oncologist to make treatment decisions.

An update on liquid biopsy analysis for diagnostic and monitoring applications in non-small cell lung cancer.

INTRODUCTION: Collection of tumor samples is not always feasible in non-small cell lung cancer (NSCLC) patients, and circulating free DNA (cfDNA) extracted from blood represents a viable alternative. Different sensitive platforms have been developed for genetic cfDNA testing, some of which are already in clinical use. However, several difficulties remain, particularly the lack of standardization of these methodologies. Areas covered: Here, the authors present a review of the literature to update the applicability of cfDNA for diagnosis and monitoring of NSCLC patients. Expert commentary: Detection of somatic alterations in cfDNA is already in use in clinical practice and provides valuable information for patient management. Monitoring baseline alterations and emergence of resistance mutations is one of the most important clinical applications and can be used to non-invasively track disease evolution. Today, different technologies are available for cfDNA analysis, including whole-genome or exome sequencing and targeted methods that focus on a selection of genes of interest in a specific disease. In the case of Next Generation Sequencing (NGS) approaches, in depth coverage of candidate mutation loci can be achieved by selecting a limited number of targeted genes.

EGFR mutations in lung cancer / Mutaciones de EGFR en cancer de pulmón

The study of epidermal growth factor receptor mutations has become essential for the treatment of lung cancer. The aim of this study was to find a correlation between morphological changes and EGFR mutational status using both immunohistochemistry and molecular techniques. We also analyzed the cross-reaction of the L858R mutation-specific monoclonal antibody in cases with HER2 amplification described previously in breast and gastric cancer. A series of 100 primary lung adenocarcinomas were examined. Exon 19 E746_A750del and exon 21 L858R mutations were studied using immunohistochemistry with two specific monoclonal antibodies. Gene mutational status was determined using real-time PCR or Sanger sequencing followed by real-time PCR when negative. EGFR mutations were detected in 22 cases (22%) by molecular techniques, being significantly more frequent in women, low grade carcinoma and lepidic subtype, (p-value <0.05 in all cases). In addition, in our series presence of tumoral necrosis correlated with absence of mutations. The anti-E746_A750del antibody achieved a 100% positive predictive value and a negative predictive value of 97.7% which could restrict the use of molecular techniques to the 7% of cases with an equivocal result. The antibody for L858R mutation showed inconsistent results compared to molecular techniques, giving false positive result in two adenocarcinomas with HER2 amplification. However, its negative predictive value was very high (98.9%). The use of real-time PCR identifies mutations not detected by the other two techniques. These new antibodies could be useful as a screening tool prior to EGFR molecular techniques (AU)

El estudio de las mutaciones de EGFR ha resultado ser esencial en el tratamiento del cáncer de pulmón. La finalidad de este trabajo ha sido estudiar la correlación entre los cambios morfológicos y el estado mutacional de EGFR utilizando técnicas de inmunohistoquímica y moleculares. Asimismo se analizó la reacción cruzada del anticuerpo anti-L858R en casos con amplificación de HER2 descrita previamente en cáncer de mama y gástrico. La serie consta de 100 adenocarcinomas pulmonares primarios. Las mutaciones E746_A750del exón-19 y L858R exón-21 se estudiaron por inmunohistoquímica con dos anticuerpos monoclonales específicos. El estado mutacional del gen se determinó mediante PCR en tiempo-real o secuenciación por Sanger seguida de PCR en tiempo-real cuando resultó negativa. Se detectaron mutaciones de EGFR en 22 casos (22%) por técnicas moleculares, siendo significativamente más frecuente en mujeres, carcinoma de bajo grado y subtipo lepídico, (p-valor<0,05 en todos los casos). Además, en nuestra serie la presencia de necrosis tumoral se correlaciona con ausencia de mutaciones. El anticuerpo anti-E746_A750del presentó un valor-predictivo-positivo del 100% y un valor-predictivo-negativo del 97,7%, lo que podría restringir el uso de técnicas moleculares al 7% de casos no-concluyentes. El anticuerpo anti-L858R mostró resultados inconsistentes en comparación con las técnicas moleculares, dando resultado falso-positivo en dos adenocarcinomas con amplificación de HER2. Sin embargo, su valor-predictivo-negativo es muy alto (98,9%). El uso de PCR en tiempo-real rescata mutaciones no detectadas por las otras dos técnicas. Estos nuevos anticuerpos podrían ser útiles como herramienta de cribado previo al estudio de EGFR mediante técnicas moleculares (AU)

Liquid Biopsy in Non-Small Cell Lung Cancer.

Liquid biopsy analyses are already incorporated in the routine clinical practice in many hospitals and oncology departments worldwide, improving the selection of treatments and monitoring of lung cancer patients. Although they have not yet reached its full potential, liquid biopsy-based tests will soon be as widespread as "standard" biopsies and imaging techniques, offering invaluable diagnostic, prognostic, and predictive information. This review summarizes the techniques available for the isolation and analysis of circulating free DNA and RNA, exosomes, tumor-educated platelets, and circulating tumor cells from the blood of cancer patients, presents the methodological challenges associated with each of these materials, and discusses the clinical applications of liquid biopsy testing in lung cancer.

Expresión inmunohistoquímica de CK19 en variantes comunes del carcinoma de mama y en subtipos histológicos infrecuentes / CK19 immunoexpression in common breast carcinomas and in special histological subtypes

El estudio del ganglio centinela es una parte esencial de la estadificación en cáncer de mama. El One-Step Nucleic Acid Amplification (OSNA) es un ensayo molecular intraoperatorio que mide la cantidad de ARNm de citoqueratina 19 (CK19) presente en la totalidad del ganglio. Debido a su mayor sensibilidad y especificidad en comparación con el examen histológico convencional se está incorporando progresivamente para la detección de metástasis en ganglio centinela, con la recomendación de demostrar la expresión inmunohistoquímica de CK19 en una biopsia previa para evitar falsos negativos. El objetivo de nuestro estudio fue evaluar la expresión de CK19 en carcinomas de mama con especial énfasis en los subtipos especiales o poco frecuentes. Se estudiaron un total de 337 carcinomas de mama distribuidos en tres series: una retrospectiva de casos no seleccionados estudiados sobre «tissue microarrays», otra retrospectiva de secciones completas, enriquecida con subtipos histológicos especiales y/o perfil molecular triple-negativo y una serie prospectiva de biopsias, sobre secciones completas, previas al estudio OSNA. Considerando los resultados de nuestras tres series, la gran mayoría de los carcinomas de mama presentan positividad difusa de CK19; por tanto, sería muy poco probable, especialmente en variantes comunes, obtener un falso negativo de OSNA debido a la falta de expresión de CK19 en el tumor primario. Se demuestra expresión heterogénea únicamente en casos de subtipos especiales (carcinoma apocrino, adenoide quístico y medular) y/o perfil TN (AU)

Sentinel lymph node assessment is an essential part of the staging procedure in breast cancer. Increasingly, One-Step Nucleic Acid Amplification (OSNA), an intraoperative molecular assay that measures the amount of cytokeratin 19 (CK19) mRNA present in the whole of the sentinel lymph node, is being used in the detection of sentinel lymph node metastasis, due to its superior sensitivity and equal specificity compared with conventional histological examination. CK19 positive immunostaining in a previous biopsy is recommended to avoid false negative results with OSNA analysis. The aim of our study was to assess the degree of CK19 positivity in series of breast carcinomas with particular emphasis on special histological subtypes. The total of 337 breast carcinomas studied were distributed in three series as follows: a retrospective unselected series studied on tissue microarray, a series of whole sections enriched for special histological subtypes and triple negative carcinomas, and a prospective series of biopsies studied in whole sections, prior to a routine OSNA assay. The results of our three series revealed that the great majority of breast carcinomas exhibits a diffuse CK19 positivity. Therefore it would be highly unlikely, especially in frequent variants, to have a false negative OSNA result due to lack of CK19 expression in the primary tumour. Heterogeneous expression was only observed in patients with infrequent variants (apocrine, adenoid cystic and medullary carcinomas) and/or TN profile (AU)

Prospective validation of the microsatellite instability prediction models: RERtest6 and RERtest8

El estudio de la inestabilidad de microsatélites (MSI) es altamente recomendable en todos los carcinomas colorrectales, tanto como una primera aproximación para identificar posibles pacientes con síndrome de Lynch, como debido a su valor pronóstico y a su asociación con una mala respuesta a los regímenes basados en 5-fluorouracilo. A pesar de estas evidencias, la aplicación del estudio de MSI en la práctica general es bastante limitada. Este hecho pone de relieve la necesidad de herramientas de cribado para facilitar la implementación del estudio de MSI. Este trabajo presenta la validación de dos modelos de predicción previamente publicados, RERtest6 y RERtest8, basados en parámetros clínico-patológicos y dirigidos a una población no seleccionada por edad. La serie incluye 206 tumores colorrectales primarios de 199 pacientes, a los que se les aplicaron los modelos de predicción que contienen 6 ó 8 parámetros, respectivamente, antes de la evaluación del estado de MSI con el panel NCI consenso o el kit de MSI Promega. Se detectó alta inestabilidad de microsatélites (MSI-H) en 21 casos (10,1%). Ambos modelos han confirmado su robustez y fueron capaces de mantener valores predictivos negativos cercanos al 95%, lo que permite la reducción del número de casos que requieren un estudio molecular al 10%. Asimismo, la naturaleza de los parámetros incluidos en los modelos, que en su mayoría ya forman parte de un examen histopatológico de rutina, los convierten en una herramienta útil y de fácil aplicación en la práctica clínica (AU)

Determining microsatellite instability status (MSI) is now highly recommended for all diagnosed colorectal carcinomas, both as a first approach to identify putative Lynch syndrome patients, and as a valuable prognostic indicator as it is associated with a poor response to 5-fluorouracil-based regimes. However, generally the implementation of MSI testing is still quite limited, suggesting the need for screening tools which would simplify MSI testing. This study presents the validation of two previously published prediction models, RERtest6 and RERtest8, based on clinicopathological features and without age restriction. The series includes 206 primary colorectal tumors from 199 patients, to which the models containing 6 or 8 parameters were applied before the assessment of MSI status, using the consensus NCI panel or the MSI Promega kit. High-level microsatellite instability (MSI-H) was detected in 21 cases (10.1%). Both models confirmed their reliability and were able to maintain negative predictive values close to 95%, reducing the number of cases to be tested by molecular methods to 10%. Furthermore, the nature of the parameters included in the models, mostly already part of a routine histopathological examination, makes them a useful tool that can be easily implemented into routine practice (AU)

Cross-reactivity of EGFR mutation-specific immunohistochemistry assay in HER2-positive tumors.

The coexpression of HER2 and EGFR L858R in a solitary nodule removed from the lung, whose mutation was not confirmed by molecular techniques, made us think about the possible existence of a cross-reaction between HER2 and the EGFR L858R-specific antibody. Our study was designed to further analyze the existence of this cross-reaction and stress the need to exclude a metastatic breast cancer when dealing with EGFR L858R-positive cases. The series consists of 42 primary breast carcinomas, 22 HER2 positive for overexpression and amplification, and 20 negative for both. EGFR mutations were studied by immunohistochemistry and confirmed using real-time PCR when positive. Immunohistochemistry assay with EGFR L858R was positive in 19 (86%) of the HER2-positive breast carcinomas and negative in all HER2-negative carcinomas. The EGFR L858R antibody gives false-positive results in most of the breast carcinomas with HER2 overexpression/amplification. As a consequence, it is essential to confirm any EGFR L858R-positive cases by molecular methods or at least discard the presence of HER2 overexpression/amplification before rendering a diagnosis. It is also important to consider that HER2 has been described in other carcinomas such as urothelial, gastric or ovarian, as well as lung, although infrequently.

ERG expression and prostatic adenocarcinoma.

ERG gene rearrangement has been identified as a highly specific alteration that is present in 40-50 % of prostate carcinomas. The standardization of an immunohistochemical assay with a novel anti-ERG antibody recently described would have significant diagnostic value. The aims of this study were to identify the incidence of this rearrangement in a Spanish population and to test the specificity of immunohistochemical ERG evaluation for prostate carcinomas. Three prostate tissue microarrays were constructed using radical prostatectomy specimens and related to grade, local invasion, and regional invasion. In addition to samples from malignant cases (160), specimens of prostatic hyperplasia (26) and high-grade prostatic intraepithelial neoplasia (10) were included. Tissue microarrays of 270 samples from most common malignant tumors (breast, colon, lung, and bladder) were also tested. All were analyzed by immunohistochemistry. Seventy-five out of 154 evaluable cases (49 %) of prostate carcinoma showed ERG expression; 52/75 showed strong staining. No ERG expression was observed in any of the high-grade prostatic intraepithelial neoplasia. ERG expression was independent of Gleason score (p = 0.160), extent of invasion (p = 0.517), and regional lymph node involvement (p = 0.816). No ERG expression was found in any other type of tumor, with the exception of one bladder cancer sample that showed focal and weak expression. The frequency of ERG detected in our study correlated with the results published for other Caucasian populations. Strong ERG protein expression was exclusively detected in prostate carcinomas, corroborating the specificity of ERG rearrangements for these tumors. Thus, detecting ERG using immunohistochemistry may be useful in routine practice in pathology departments.

Maternal treatment with oleoyl-estrone induces resistance to lipid accrual in their descendants.

OBJECTIVE: To determine whether treatment of rat dams with oleoyl-estrone (OE) has an effect on the offspring's long-term response to diet restriction during lactation. METHODS AND PROCEDURES: Control, OE-treated, and diet-restricted dams were treated up to day 15 of lactation. Changes in food intake and body weight were recorded for dams and their pups. After weaning, pups received a 4-week standard diet followed by a 4-week period of high-fat diet. Lipid, protein, and energy content of pups plus energy intake and efficiency. Serum metabolites (glucose, urea, and cholesterol) and serum hormones (adiponectin, leptin, insulin, and sexual hormones). RESULTS: Neither pups from dams in the OE-treated nor in the diet-restricted group showed significant changes in weight, though these two groups ingested 79% of food ingested by controls. At weaning, the pups from OE-treated rats were smaller than those of the control or diet-restricted groups. These pups maintained the differences in size and lipid content during the 4-week standard-diet period, whereas pups from diet-restricted dams showed a sharp decrease in their lipid content. During the 4 weeks of high-fat diet, the male offspring from OE-treated dams increased the difference in lipid content in relation to the pups from control dams whereas in females the differences decreased. Female offspring from diet-restricted dams showed the most marked changes in metabolite and hormone levels in relation to controls. DISCUSSION: Treatment of lactating dams with OE programs the metabolic response of their offspring to resist the challenge of a high-fat diet that would lead to obesity in adulthood.

Treatment of pregnant rats with oleoyl-estrone slows down pup fat deposition after weaning.

BACKGROUND: In rats, oral oleoyl-estrone (OE) decreases food intake and body lipid content. The aim of this study was to determine whether OE treatment affects the energy metabolism of pregnant rats and eventually, of their pups; i.e. changes in normal growth patterns and the onset of obesity after weaning. METHODS: Pregnant Wistar rats were treated with daily intragastric gavages of OE in 0.2 ml sunflower oil from days 11 to 21 of pregnancy (i.e. 10 nmol oleoyl-estrone/g/day). Control animals received only the vehicle. Plasma and hormone metabolites were determined together with variations in cellularity of adipose tissue. RESULTS: Treatment decreased food intake and lowered weight gain during late pregnancy, mainly because of reduced adipose tissue accumulation in different sites. OE-treated pregnant rats' metabolic pattern after delivery was similar to that of controls. Neonates from OE-treated rats weighed the same as those from controls. They also maintained the same growth rate up to weaning, but pups from OE-treated rats slowed their growth rate afterwards, despite only limited differences in metabolite concentrations. CONCLUSION: The OE influences on pup growth can be partially buffered by maternal lipid mobilization during the second half of pregnancy. This maternal metabolic "imprinting" may condition the eventual accumulation of adipose tissue after weaning, and its effects can affect the regulation of body weight up to adulthood.

Oleoyl-estrone treatment to late pregnant and mid-lactating rats affects the expression of lipid metabolism genes.

The purpose of this study was to determine whether OE treatment affects the expression of genes related to lipid metabolism under two physiological conditions: late pregnancy and mid-lactation, both characterized by lipid mobilization. Samples of periovarian and retroperitoneal adipose tissue from 21-day pregnant or 15-day lactating dams were used. The expression of LPL, FATP1, FABP4, HSL, ACC1, FAS, PEPCK, GLUT4, PDK4, SREBP1c, adiponutrin and leptin, were compared with their expression in virgin rats. In pregnant rats, FABP4, HSL, PEPCK and PDK4 were over expressed in the periovarian site compared to virgin rats, whereas adiponutrin, FAS, GLUT4 and SREBP1c were underexpressed; the retroperitoneal fat depot showed a similar pattern but ACC1 and leptin were also underexpressed. OE treatment caused a generalized decrease in gene expression in both adipose depots. In lactating dams, the gene expression profile at the periovarian depot was similar to that observed in pregnant rats. OE treatment mimicked the trend observed in pregnant rats, although the intensity of the gene expression changes was lower. After OE treatment, the retroperitoneal adipose depot showed a completely different pattern since the values were close to those of virgin rats. These results corroborate that OE effects in adipose tissue, lowering lipids and depressing their metabolism, already described under other physiological situations, can be also found in late pregnancy and lactation.

Effects of oral estrone on rat energy balance.

Oral doses of estrone from 10 nmol/(kg day) to 10 micromol/(kg day) were given to adult Wistar male rats for 10 days. Body composition, energy balance, total body estrone balance and plasma metabolites and hormones were measured at the end of the treatment. Body weight (as well as food intake, body energy, fat and water accrual) increased at doses in the 10--100 nmol/(kg day) range, but decreased at higher doses. Energy expenditure decreased with increasing doses of estrone. Plasma metabolite changes suggested the maintenance of energy homeostasis, and lipid parameters indicated that lipid mobilization increased with the increasing doses of estrone. Plasma estrone, acyl-estrone and estradiol levels decreased at low doses and increased at high doses of estrone. We conclude that: (a) repeated estrone gavages, even at very high doses, do not result in the accrual of estrone in the body; (b) low doses of estrone promote growth and high doses decrease body mass and fat accretion; (c) administration of estrone at low doses decreases its circulating levels and the levels of estradiol and acyl-estrone, a situation reverted at higher doses and (d) estrone administration induces a dose-dependent shift towards lower energy expenditure.

Tamoxifen does not prevent the mobilization of body lipids elicited by oleoyl-estrone.

Oleoyl-estrone is a powerful, slimming adipose tissue-derived signal that has biological effects widely opposed to those of its estrone moiety. The present experiment was designed to determine whether oleoyl-estrone effects on body energy are mediated by the estrogen receptor, blocked with the antagonist tamoxifen. Male Wistar rats were given daily oral doses of 10 micromol/kg d of oleoyl-estrone in oil containing 0 or 0.40 mg/kg d of tamoxifen. The data were compared with controls receiving only oil or 50 nmol/kg d of free estrone. After 10 days, the rats were killed, and their body composition and plasma metabolites and hormones were analyzed. Rats receiving estrone increased their body energy and lipid content compared with controls. Both groups of oleoyl-estrone-treated rats lost body weight, energy, and lipid; the losses in the rats receiving tamoxifen alone were less marked than in those receiving oleoyl-estrone. No significant changes in plasma glucose or triacylglycerols were observed. The patterns of change of estrone sulphate, estradiol, and oleoyl-estrone were consistent with a noticeable hydrolysis of oleoyl-estrone. The lack of differences in the fat mass in oleoyl-estrone-treated rats irrespective of the presence of tamoxifen suggested that the estrogenic pathway was not responsible for the slimming effects observed. Thus, it can be concluded that oleoyl-estrone effects are not mediated through its conversion to estrone or estradiol acting through the estrogen receptor. Tamoxifen partly mimicked the slimming effects of oleoyl-estrone; this could be speculatively explained by tamoxifen acting through the oleoyl-estrone signalling pathway.