Precision medicine in the era of multi-omics: can the data tsunami guide rational treatment decision?

Precision medicine for cancer is rapidly moving to an approach that integrates multiple dimensions of the biology in order to model mechanisms of cancer progression in each patient. The discovery of multiple drivers per tumor challenges medical decision that faces several treatment options. Drug sensitivity depends on the actionability of the target, its clonal or subclonal origin and coexisting genomic alterations. Sequencing has revealed a large diversity of drivers emerging at treatment failure, which are potential targets for clinical trials or drug repurposing. To effectively prioritize therapies, it is essential to rank genomic alterations based on their proven actionability. Moving beyond primary drivers, the future of precision medicine necessitates acknowledging the intricate spatial and temporal heterogeneity inherent in cancer. The advent of abundant complex biological data will make artificial intelligence algorithms indispensable for thorough analysis. Here, we will discuss the advancements brought by the use of high-throughput genomics, the advantages and limitations of precision medicine studies and future perspectives in this field.

Clinical utility of circulating tumor DNA sequencing with a large panel: a National Center for Precision Medicine (PRISM) study

BACKGROUND

Circulating tumor DNA (ctDNA) sequencing is a promising approach for tailoring therapy in patients with cancer. We report hereby the results from a prospective study where we investigated the impact of comprehensive molecular profiling of ctDNA in patients with advanced solid tumors.

PATIENTS AND METHODS

Genomic analysis was performed using the FoundationOne Liquid CDx Assay [324 genes, tumor mutational burden (TMB), microsatellite instability status]. Each individual genomic report was reviewed and discussed weekly by a multidisciplinary tumor board (MTB). Actionable targets were classified by ESMO Scale for Clinical Actionability of Molecular Targets (ESCAT) tier leading to molecular-based treatment suggestions wherever it was possible.

RESULTS

Between December 2020 and November 2021, 1772 patients with metastatic solid tumors underwent molecular profiling. Median time to assay results was 12 days. Results were contributive for 1658 patients (94%). At least one actionable target was detected in 1059 patients (64%) with a total of 1825 actionable alterations including alteration of the DNA damage repair response pathway (n = 336, 18%), high TMB (>16 mutations/Mb; n = 243, 13%), PIK3CA mutations (n = 150, 8%), ERBB family pathway alterations (n = 127, 7%), PTEN alterations (n = 95, 5%), FGFR alterations (n = 67, 4%) and MET activations (n = 13, 0.7%). The MTB recommended a matched therapy for 597 patients (56%) with a total of 819 therapeutic orientations: clinical trials (n = 639, 78%), off-label/compassionate use (n = 81, 10%), approved drug (n = 51, 6%), and early access program (n = 48, 6%). In total, 122 patients (21%) were treated. Among the assessable patients (n = 107), 4 (4%) had complete response, 35 (33%) had partial response, 27 (25%) had stable disease, and 41 (38%) a progressive disease as best response. The median progression-free survival and median overall survival were 4.7 months (95% confidence interval 2.7-6.7 months) and 8.3 months (95% confidence interval 4.7-11.9 months) respectively.

CONCLUSIONS

ctDNA sequencing with a large panel is an efficient approach to match patients with advanced cancer with targeted therapies.

Abstract 3413: Clinical utility of circulating tumor DNA sequencing with a large panel: The experience of Gustave Roussy/National Center for Precision Medicine (PRISM)

Background: Circulating tumor DNA (ctDNA) sequencing is a promising approach for testing gene alterations and tailoring therapy in cancer patients given, its limited invasiveness, high sensitivity and potential to comprehensively represent tumor heterogeneity. Here, we report the results from a single-center study conducted at Gustave Roussy (Villejuif, France) where we investigated the impact of comprehensive molecular profiling of ctDNA in patients with advanced solid tumors.

Methods: Genomic analysis was performed using the Foundation One Liquid CDx Assay (324 genes, tumor mutational burden [TMB], microsatellite instability status). Each individual genomic report was reviewed and discussed weekly by a multidisciplinary tumor board (MTB) dedicated to precision medicine, attended by experts in clinical oncology, molecular biology, and clinical genetics. Actionable targets were defined by the MTB according to the existing level of evidence (classified by ESCAT tier), and molecular-based treatment suggestions were proposed where possible.

Results: Between December 2020 and November 2021, 1772 patients with metastatic solid tumors underwent molecular profiling. Median time to assay results was 12 days. Results were contributive for 1658 patients (94%). At least one actionable target was detected in 1059 patients (64%) with a total of 1825 theragnostic alterations including : high blood TMB (> 16 mutations/Mb) (N= 243, 13%), alteration of the DNA damage repair response pathway (N=336, 18%), PIK3CA mutations (N=150, 8%), FGFR alterations (N= 67, 4%), MET activations (N=13, 0.7%), ERBB family pathway alterations (N=127, 7%) and PTEN mutations (N=95, 5%). Overall, the MTB recommended a matched therapy for 597 patients (56%) with a total of 819 therapeutic orientations: clinical trials (N= 639, 78%), off label/compassionate use (N=81, 10%), drug with a market authorization (N=51, 6%) and drug within an early access program (N=48, 6%). MTB did not recommend treatment for 462 patients (44%) with targetable molecular alterations for the following reasons: no clinical trial (N=421, 65%), matched treatment was already received (N=169, 26%), worsening of performance status (N= 49, 8%).

Conclusions: This large-scale study demonstrates that liquid biopsy with a large NGS ctDNA panel is an efficient approach to match patients to genomically directed clinical trials/targeted therapies. Outcomes of patients treated with matched therapy will be presented at the meeting.

Citation Format: Arnaud Bayle, Laila Belcaid, Miha Aldea, Florent Peyraud, Patricia Martin Romano, Félix Blanc-Durand, Rebecca Clodion, Santiago Ponce, Claudio Nicotra, Antoine Hollebecque, Yohann Loriot, Benjamin Besse, Damien Vasseur, Ludovic Lacroix, Etienne Rouleau, Jean-Charles Soria, Fabrice Barlesi, Geoffrey R. Oxnard, Fabrice Andre, Antoine Italiano. Clinical utility of circulating tumor DNA sequencing with a large panel: The experience of Gustave Roussy/National Center for Precision Medicine (PRISM) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3413.

Abstract 3414: Systematic comparison of ctDNA vs tissue sequencing with a large panel to guide therapy in patients with advanced cancer: A study from the French National Center for Precision Medicine (PRISM)

Background: Genomic profiling with tissue sequencing is still considered as the gold standard despite several limitations including screening failures due to limited tissue availability, and inability to capture intratumor spatial and temporal heterogeneity, which may impair accurate treatment selection. Several studies have demonstrated the potential of circulating tumor DNA (ctDNA) to detect genomic alterations at high accuracy compared with tissue analysis. However, no studies have comprehensively evaluated differences between tissue and ctDNA by using a large panel in the same cohort.

Methods: Genomic analysis was performed for each patient by using the Foundation One Liquid CDx Assay and the Foundation One CDx Assay (324 genes, tumor mutational burden [TMB], microsatellite instability). Each individual genomic report was reviewed and discussed weekly by a multidisciplinary tumor board (MTB). Actionable targets were defined by the MTB according to the existing level of evidence (ESCAT tiers) and molecular-based treatment suggestions were proposed where possible.

Results: Between Dec 2020 and Nov 2021, 1021 patients (median age: 62 years) with advanced cancer underwent both tissue and ctDNA NGS. Five most frequent tumor types were colorectal (N=137,13%), NSCLC (N=130,13%), breast (N=120, 12%), prostate (N=82, 8%) and pancreas (N=65, 6%). Median time elapsed between request and assay results was 12 days for ctDNA and 46 days for tissue. Testing failure was 15% for tissue and 3.9% for ctDNA. Overall, 824 (81%) patients had evaluable results for both tissue and liquid. Total number of cancer-related alterations and variants of unknown significance were 4704 and 11673 vs 4645 and 7481 for ctDNA and tissue, respectively. Proportion of patients with a higher number of cancer alterations identified in ctDNA compared with tissue increased in parallel with the time elapsed between the tissue and ctDNA sampling (45% vs 33% for a delay > 26 months or < 8 months). MSI and TMB status were concordant for 71% and 64% of patients, respectively. MSI status was evaluable for 97% of patients through ctDNA vs 90% through tissue. Number of actionable alterations was similar in 346 (42%) of cases, whereas it was higher in tissue for 289 (35%) and in liquid for 189 (23%) patients. ctDNA profiling allowed the identification of an ESCAT I/II or III or IV alteration not present in tissue for 74 (9%), 113 (14%) and 52 (6%) patients, respectively. Overall, MTB recommended a matched therapy for 430 patients (52%). Such a recommendation would not have been made without the results of ctDNA for 120 patients (15%).

Conclusion: This systematic comparison of ctDNA vs tissue sequencing demonstrates the capacity of ctDNA for capturing clinically relevant alterations to guide therapy in cancer patients with high accuracy and rapid turnover results.

Citation Format: Arnaud Bayle, Florent Peyraud, Laila Belcaid, Maxime Brunet, Miha Aldea, Rebecca Clodion, Paul Dubos, Damien Vasseur, Claudio Nicottra, Santiago Ponce, Isabelle Soubeyran, Emmanuel Khalifa, Yohann Loriot, Benjamin Besse, Ludovic Lacroix, Etienne Rouleau, Geoffrey Oxnard, Fabrice Barlesi, Fabrice Andre, Antoine Italiano. Systematic comparison of ctDNA vs tissue sequencing with a large panel to guide therapy in patients with advanced cancer: A study from the French National Center for Precision Medicine (PRISM) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3414.

Evaluating the appropriateness of a community pharmacy model for a colorectal cancer screening program in Catalonia (Spain)

Background

The traditional model of community pharmacy has changed, with patients, caregivers and consumers having access to many cognitive services other than the traditional dispensing and supply of medicines. In December 2009, a population-based colorectal cancer screening program started in Barcelona, introducing the community pharmacist and the professional expertise of the pharmacist into the organisational model.

Aim

To evaluate the program implementation process in the pharmacies, identify barriers and facilitators, and know the opinion of the professionals involved in the colorectal cancer screening program in Catalonia (Spain).

Methods

Cross-sectional study of the pharmacies that participated in the first round of the program during the first and second trimester of 2010 in Barcelona. A validated questionnaire was used to analyse several functional aspects in the implementation process. Qualitative aspects about the opinion of the pharmacist were studied. A descriptive and bivariate analysis was performed.

Results

All the pharmacies involved in the program (n = 74) participated in the study. The majority of the sample population was composed of women (70.3%), mean age 44.9 years, and most of them (74%) had attended a specific training session. Pharmacists considered their participation in the program to be an added value to their professional role and a way to increase consumer’s confidence on this kind of services. The average time to provide the service was estimated to be less than 10 minutes per consumer. Only three (4.1%) pharmacists considered that the program involved a lot of extra work in the daily activities of the pharmacy. The level of satisfaction of the pharmacists was very high.

Conclusions

Community pharmacies can be a successful alternative and great resource to implement a population cancer screening program. This functional model can improve the accessibility and participation rates on target population. The level of motivation of the community pharmacist, the specific training program and the perception to give a better care for their patients can be an enabler.

Factors influencing completion of multi-dose vaccine schedules in adolescents: a systematic review

BACKGROUND

Completion of multiple dose vaccine schedules is crucial to ensure a protective immune response, and maximise vaccine cost-effectiveness. While barriers and facilitators to vaccine uptake have recently been reviewed, there is no comprehensive review of factors influencing subsequent adherence or completion, which is key to achieving vaccine effectiveness. This study identifies and summarises the literature on factors affecting completion of multi-dose vaccine schedules by adolescents.

METHODS

Ten online databases and four websites were searched (February 2014). Studies with analysis of factors predicting completion of multi-dose vaccines were included. Study participants within 9-19 years of age were included in the review. The defined outcome was completion of the vaccine series within 1 year among those who received the first dose.

RESULTS

Overall, 6159 abstracts were screened, and 502 full texts were reviewed. Sixty one studies were eligible for this review. All except two were set in high-income countries. Included studies evaluated human papillomavirus vaccine, hepatitis A, hepatitis B, and varicella vaccines. Reported vaccine completion rates, among those who initiated vaccination, ranged from 27% to over 90%. Minority racial or ethnic groups and inadequate health insurance coverage were risk factors for low completion, irrespective of initiation rates. Parental healthcare seeking behaviour was positively associated with completion. Vaccine delivery in schools was associated with higher completion than delivery in the community or health facilities. Gender, prior healthcare use and socio-economic status rarely remained significant risks or protective factors in multivariate analysis.

CONCLUSIONS

Almost all studies investigating factors affecting completion have been carried out in developed countries and investigate a limited range of variables. Increased understanding of barriers to completion in adolescents will be invaluable to future new vaccine introductions and the further development of an adolescent health platform. PROSPERO reg# CRD42014006765.

Comparison of haematopoietic stem cell engraftment through the retro-orbital venous sinus and the lateral vein: alternative routes for bone marrow transplantation in mice

Bone marrow transplantation in mice is performed by intravenous administration of haematopoietic repopulating cells, usually via the lateral tail vein. This technique can be technically challenging to carry out and may cause distress to the mice. The retro-orbital sinus is a large area where there is a confluence of several vessels that provides an alternative route for intravenous access. Retro-orbital injection, although aesthetically unpleasant, can be performed rapidly without requiring mechanical restriction or heat-induced vasodilation. In addition, this technique can be easily learned by novice manipulators. This route of administration has been reported for use in bone marrow transplantation but there is no comparison of retro-orbital and tail vein injections reported for this specific purpose, although both routes have been compared for many other applications. Here, we provide for the first time a comprehensive comparison between tail vein and retro-orbital injections for two different bone marrow transplant scenarios in P3B and B6D2F1 mice. In both cases, no significant differences regarding donor engraftment were observed between mice transplanted using each of the techniques. Haematological counts and leukocyte subpopulation distribution were practically identical between both animal groups. Moreover, donor engraftment levels were less homogenous when cells were transplanted by tail vein injection, probably due to a higher risk of failure associated with this technique. All these data suggest that retro-orbital injection is a compelling alternative to conventional tail vein injection for bone marrow transplant in mice, providing similar and more homogenous haematopoietic reconstitution.

Gearbox gene expression and growth rate

Regulation of gene expression in prokaryotic cells usually takes place at the level of transcription initiation. Different forms of RNA polymerase recognizing specific promoters are engaged in the control of many prokaryotic regulons. This also seems to be the case for some Escherichia coli genes that are induced at low growth rates and by nutrient starvation. Their gene products are synthesized at levels inversely proportional to growth rate, and this mode of regulation has been termed gearbox gene expression. This kind of growth-rate modulation is exerted by specific transcriptional initiation signals, the gearbox promoters, and some of them depend on a putative new σ factor (RpoS). Gearbox promoters drive expression of morphogenetic and cell division genes at constant levels per cell and cycle to meet the demands of cell division and septum formation. A mechanism is proposed that could sense the growth rate of the cell to alter gene expression by the action of specific σ factors.

Glioblastoma stem cells: a new target for metformin and arsenic trioxide

The high malignancy of glioblastoma has been recently attributed to the presence, within the tumor, of glioblastoma stem cells (GSC) poorly responsive to chemo- and radiotherapy. Here, the potential employment of metformin and arsenic trioxide (ATO) in glioblastoma therapy is discussed focusing on their effects on GSC. Metformin exerts anticancer effects by primarily blocking the pivotal LKB1/AMPK/mTOR/S6K1 pathway-dependent cell growth, induces selective lethal effects on GSC by impairing the GSC-initiating spherogenesis and inhibits the proliferation of CD133+ cells, while having a low or null effect on differentiated glioblastoma cells and normal human stem cells. Metformin and ATO induce autophagy and apoptosis in glioma cells by inhibiting and stimulating the PI3K/Akt and the mitogen-activated protein kinase pathways, respectively. Both drugs promote differentiation of GSC into non-tumorigenic cells. In this regard, metformin acts via activation of the AMPK-FOXO3 axis, whereas ATO blocks the interleukin 6-induced promotion of STAT3 phosphorylation. Blood-brain barrier, easily crossed by metformin but not by ATO, undergoes important glioblastoma-induced alterations that increase its permeability, thus allowing ATO to distribute more into the glioblastoma bulk than in the normal brain parenchyma. A prompt clinical assessment of metformin and ATO in glioblastoma patients would represent a valid attempt to improve their survival.

Metformin plus PIAF combination chemotherapy for hepatocellular carcinoma

OBJECTIVES

Metformin, the most used oral antidiabetic drug for the treatment of type 2 diabetus mellitus, has proved encouraging results when used in the treatment of various types of cancer such as triple-negative breast cancer. Despite compelling evidence of a role of metformin as an anticancer drug, the mechanisms by which metformin exerts its oncostatic actions are not fully understood yet. Therefore, we tried to bring new insights by analyzing the anti-neoplastic effect of metformin for hepatocellular carcinoma-derived stem-like cells treated with conventional combination chemotherapy.

METHODS

Cancer stem-like cells previusly isolated from a hepatocellular carcinoma biopsy were treated with metformin, PIAF chemotherapy regimen and the combination of these two protocols. Measurements of lipid peroxidation, reduced glutathione, fluorescein diacetate and proliferation rates were determined, apart from the autophagy assay and apoptosis determination by chip flow cytometry.

RESULTS

Metformin alone and especially metformin in association with PIAF increases oxidative stress within the cells by increasing the levels of lipid peroxids as well as decreasing the levels of reduced glutathione. The MTT cell proliferation assay showed decreased prolife-ration rates for the arm treated with metformin and with the combination of drugs in comparison with the control arm, proving high correlation with the oxidative stress results. The autophagy assay and determination of apoptosis by chip flow cytometry confirmed the results obtained in the previous assays.

CONCLUSION

Metformin could be used in chemotherapy treatments to induce reactive oxygen species and increase the cytostatics effects within the tumor cell. Still, further experiments must be carried out on murine models before we can move on and use this drugs in the adjuvant setting for unresectable primary liver cancer.

Reverse phase protein microarrays quantify and validate the bioenergetic signature as biomarker in colorectal cancer

A reverse phase protein microarray approach has been applied to quantify proteins of energy metabolism in normal and tumor biopsies of colorectal cancer (CRC) patients. The metabolic proteome of CRC specimens revealed a profound shift towards and enhanced glycolytic phenotype and concurrent mitochondrial alteration. The metabolic signature discriminated CRC patients with highly significant differences in overall and disease-free prognosis. The quantification of the bioenergetic signature of the tumor offers a relevant biomarker of CRC that could contribute in the handling of these patients.

Antidiabetic pharmacology: a link between metabolic syndrome and neuro-oncology?

One of the main topics of the annual meeting of the American Society for Clinical Oncology in 2011 were the results presented on breast cancer chemotherapy and concomitant administration of the oral antidiabetic metformin. The overall agreement was that current evidence is just enough to dramatically change the clinical practice of oncology, and in our case, brain cancer treatment, and that further research is needed to address the relationship between diabetes, metabolism, insulin analogues and neoplasia. Still, it is very interesting to explore the potentially beneficial effects of metformin in glioma chemo/immunotherapy and wait for results in the clinic. In the current paper we present the cell and molecular aspects of the metabolic syndrome, metformin administration and cancer chemotherapy, with a special emphasis in neuro-oncology, since brain tumors are usually devastating diseases with an extremely high mortality within two years of diagnosis even when surgical, radiotherapeutic and chemotherapeutic interventions are applied.

Metformin plus temozolomide-based chemotherapy as adjuvant treatment for WHO grade III and IV malignant gliomas

PURPOSE

Glioblastoma multiforme (GBM) remains one of the most devastating diseases known to man and affects more than 17,000 patients in the United States alone every year. This malignancy infiltrates the brain early in its course and makes complete neurosurgical resection almost impossible. Recent years have brought significant advances in tumor biology, including the discovery that many cancers, including gliomas, appear to be supported by cells with stem-like properties. In the current study we have investigated the effects of combining metformin with the standard treatment-of-care, as this drug, already used in the treatment of diabetes mellitus, has shown surprising results in the treatment of breast cancer, being also associated with lower mortality in several other malignancies.

METHODS

The subjects of the current study were 8 patients with newly diagnosed high-grade gliomas, operated at the Department of Neurosurgery - Clinical University Emergency Hospital, Cluj Napoca. Tumor tissue cultures were established and characterized using immunofluorescence microscopy and PCR analysis and the sensitivity to metformin, epidermal growth factor (EGF) and temozolomide (TMZ) was tested. Microvascular density (MVD) assay was performed on the tumor samples.

RESULTS

Seven of the 8 cases had a positive correlation between the number of endothelial cells, the phenotype of isolated tumor cells and the response to adjuvant chemoradiotherapy. The isolated tumor cells had a stem-like behavior, being resistant to conventional drugs. In most cases there was no statistical significant difference between TMZ alone and TMZ plus EGF arms, but there was a important difference between TMZ alone and TMZ plus metformin arms in 6 of the cases.

CONCLUSION

New drugs and targeted molecular therapies are important for future therapeutics, but sometimes we must not exclude drugs already used in the clinic that might have remarkable results. Such is the case of metformin, a drug used for decades in the treatment of type 2 diabetes mellitus that has proven to enhance the effect of TMZ in the treatment of breast cancer and, starting with this paper, of brain cancer.

1,25-Dihydroxyvitamin D3 stimulates vascular smooth muscle cell proliferation through a VEGF-mediated pathway

Atherosclerosis is a complex process characterized by an increase in the wall thickness owing to the accumulation of cells and extracellular matrix between the endothelium and the smooth muscle cell wall. This process is associated with different pathologies and it is accelerated in patients with chronic renal failure. In these patients, decreased synthesis of 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) leads to secondary complications, like hyperparathyroidism, and treatment with 1,25(OH)(2)D(3) is a common practice. The effect of 1,25(OH)(2)D(3) on vascular smooth muscle cells (VSMCs) calcification has been widely studied, but the role of 1,25(OH)(2)D(3) on VSMC proliferation remains obscure. We have analyzed the effects of 1,25(OH)(2)D(3) in the proliferation of VSMC. We found that 1,25(OH)(2)D(3) (5-100 nM) induces a dose-dependent increase in VSMC proliferation in quiescent cells and in cells stimulated to grow. This increase in proliferation is achieved by shortening the G1 phase. The effect of 1,25(OH)(2)D(3) on VSMC proliferation is mediated by an increase of the expression of vascular endothelial growth factor A (VEGF), as the inhibition of VEGF activity totally blunted the 1,25(OH)(2) D(3)-induced VSMC proliferation. We found this increase in proliferation in vitro, ex vivo in aortic rings incubated with 1,25(OH)(2)D(3), and in vivo in animals with a model of chronic renal failure (5/6 nephrectomy) treated with 1,25(OH)(2)D(3) (1 mug/kg three times a week for 8 weeks). Thus, we conclude that 1,25(OH)(2)D(3) induces increases in VSMC proliferation through an increase on VEGF expression.

Mercury and trace element fractionation in Almaden soils by application of different sequential extraction procedures

A comparative evaluation of the mercury distribution in a soil sample from Almaden (Spain) has been performed by applying three different sequential extraction procedures, namely, modified BCR (three steps in sequence), Di Giulio-Ryan (four steps in sequence), and a specific SEP developed at CIEMAT (six steps in sequence). There were important differences in the mercury extraction results obtained by the three procedures according to the reagents applied and the sequence of their application. These findings highlight the difficulty of setting a universal SEP to obtain information on metal fractions of different mobility for any soil sample, as well as the requirement for knowledge about the mineralogical and chemical characteristics of the samples. The specific six-step CIEMAT sequential extraction procedure was applied to a soil profile (Ap, Ah, Bt1, and Bt2 horizons). The distribution of mercury and major, minor, and trace elements in the different fractions were determined. The results indicate that mercury is mainly released with 6 M HCl. The strong association of mercury with crystalline iron oxyhydroxides, present in all the horizons of the profile, and/or the solubility of some mercury compounds in such acid can explain this fact. Minor mercury is found in the fraction assigned to oxidizable matter and in the final insoluble residue (cinnabar).

[Differential effect of vitamin D analogues on the proliferation of vascular smooth muscle cells]

Atherosclerosis is the principal cause of myocardial infarction, stroke, and peripheral vascular disease, accounting for nearly half of all mortality in developed countries. The excessive growth of vascular smooth muscle cells is an important component in the development of atherosclerotic lesion. The direct effect of calcitriol and vitamin D analogs on the VSMCs proliferation is not clear. In this study we have analysed if calcitriol, Paricalcitol (19-nor-1,25-dihydroxy-vitamin D2) and EB1089 (experimental analog used as anticancerous) modify proliferation and the expression of vitamin D receptor (VDR) gene that is regulated at the transcriptional level by itself in the VSMCs. VSMCs proliferation was analysed by BrdU incorporation and VDR gene expression using RT-PCR. VSMCs proliferation was stimulated when calcitriol was added to the culture. VSMCs proliferation was significantly lower with analogs at the same dose. With regard to the functional study, the expression of VDR gene was upregulated by calcitriol at a concentration of 100 nM. There were no changes in this expression with the analogs. In conclusion, calcitriol, do not modify VSMCs proliferation. Therefore, Paricalcitol could have a minor proliferating effect on the wall of vessels that vitamin D.

[Nicotinic Receptor, galantamine and Alzheimer disease]

Population aging has increased and will drastically increase the prevalence of Alzheimer disease. The disease develops inexorably towards a syndrome of marked cognitive impairment, accompanied of emotional alterations and profound changes of personality. The patient loses its autonomy, and requires special attention of caregivers; this leads to a decrease of the quality of life, not only of the patient but also of its caregivers and family. The reduction of the number of functional nicotinic receptors in brain keeps pace with neurological symptoms and the severity of the disease (cholinergic theory of Alzheimer disease). There is a pleyade of data and observations reinforcing the idea that improving cholinergic neurotransmission is an investment in memory. Up to now, although with limited success, this improvement has been achieved only with the reversible inhibitors of acetylcholinesterase tacrine, rivastigmine and donepezil, available in the clinic since a few years. The last approved has been galantamine that in spite of being a modest inhibitor of acetylcholinesterase, improves memory (ADAS cog test) and slows down cognitive impairment of Alzheimer patients. To explain this therapeutic effect, a second mechanism of action for galantamine has been suggested, the positive allosteric modulation of presynaptic nicotinic receptors, that will favour the release of acetylcholine and other neurotransmitters involved in memory formation. Furthermore, galantamine possesses neuroprotectant antiapoptotic effects, according to recent data from our laboratory. These effects provide new ideas and therapeutic targets that might help to find novel and efficacious treatments for patients suffering Alzheimer disease.

Whi3 binds the mRNA of the G1 cyclin CLN3 to modulate cell fate in budding yeast

Eukaryotic cells commit in G1 to a new mitotic cycle or to diverse differentiation processes. Here we show that Whi3 is a negative regulator of Cln3, a G1 cyclin that promotes transcription of many genes to trigger the G1/S transition in budding yeast. Whi3 contains an RNA-recognition motif that specifically binds the CLN3 mRNA, with no obvious effects on Cln3 levels, and localizes the CLN3 mRNA into discrete cytoplasmic foci. This is the first indication that G1 events may be regulated by locally restricting the synthesis of a cyclin. Moreover, Whi3 is also required for restraining Cln3 function in meiosis, filamentation, and mating, thus playing a key role in cell fate determination in budding yeast.

Osmotic stress causes a G1 cell cycle delay and downregulation of Cln3/Cdc28 activity in Saccharomyces cerevisiae

Moderate hyperosmotic stress on Saccharomyces cerevisiae cells produces a temporary delay at the G1 stage of the cell cycle. This is accompanied by transitory downregulation of CLN1, CLN2 and CLB5 transcript levels, although not of CLN3, which codes for the most upstream activator of the G1/S transition. Osmotic shock to cells synchronized in early G1, when Cln3 is the only cyclin present, causes a delay in cell cycle resumption. This points to Cln3 as being a key cell cycle target for osmotic stress. We have observed that osmotic shock causes downregulation of the kinase activity of Cln3-Cdc28 complexes. This is concomitant with a temporary accumulation of Cln3 protein as a result of increased stability. The effects of the osmotic stress in G1 are not suppressed in CLN3-1 cells with increased kinase activity, as the Cln3-Cdc28 activity in this mutant is still affected by the shock. Although Hog1 is not required for the observed cell cycle arrest in hyperosmotic conditions, it is necessary to resume the cell cycle at KCl concentrations higher than 0.4 M.

The yeast ser/thr phosphatases sit4 and ppz1 play opposite roles in regulation of the cell cycle

Yeast cells overexpressing the Ser/Thr protein phosphatase Ppz1 display a slow-growth phenotype. These cells recover slowly from alpha-factor or nutrient depletion-induced G1 arrest, showing a considerable delay in bud emergence as well as in the expression of the G1 cyclins Cln2 and Clb5. Therefore, an excess of the Ppz1 phosphatase interferes with the normal transition from G1 to S phase. The growth defect is rescued by overexpression of the HAL3/SIS2 gene, encoding a negative regulator of Ppz1. High-copy-number expression of HAL3/SIS2 has been reported to improve cell growth and to increase expression of G1 cyclins in sit4 phosphatase mutants. We show here that the described effects of HAL3/SIS2 on sit4 mutants are fully mediated by the Ppz1 phosphatase. The growth defect caused by overexpression of PPZ1 is intensified in strains with low G1 cyclin levels (such as bck2Delta or cln3Delta mutants), whereas mutation of PPZ1 rescues the synthetic lethal phenotype of sit4 cln3 mutants. These results reveal a role for Ppz1 as a regulatory component of the yeast cell cycle, reinforce the notion that Hal3/Sis2 serves as a negative modulator of the biological functions of Ppz1, and indicate that the Sit4 and Ppz1 Ser/Thr phosphatases play opposite roles in control of the G1/S transition.

G1 cyclins block the Ime1 pathway to make mitosis and meiosis incompatible in budding yeast

Diploid yeast cells switch from mitosis to meiosis when starved of essential nutrients. While G1 cyclins play a key role in initiating the mitotic cell cycle, entry into meiosis depends on Ime1, a transcriptional activator regulated by both nutritional and cell-type signals. We show here that G1 cyclins downregulate IME1 transcription and prevent the accumulation of the Ime1 protein within the nucleus, which results in repression of early-meiotic gene expression. As G1-cyclin deficient cells do not require nutrient starvation to undergo meiosis, G1 cyclin would exert its role by transmitting essential nutritional signals to Ime1 function. The existence of a negative cross-talk mechanism between mitosis and meiosis may help explain why these two developmental options are incompatible in budding yeast.

Functional analysis of yeast essential genes using a promoter-substitution cassette and the tetracycline-regulatable dual expression system

A promoter-substitution cassette has been constructed that allows one-step substitution of chromosomal gene promoters for the tetracycline-regulatable tetO promoter in yeast cells, which uses kanMX4 as selective marker for geneticin resistance. Oligonucleotides for PCR amplification of the cassette are designed to allow homologous recombination through short flanking regions of homology with the upstream sequences of the chromosomal gene, upon transformation of target cells. By testing three essential genes of chromosome XV (YOL135c, YOL142w and YOL144w), the system causes tetracycline-dependent conditional growth of the cells, being modulatable by intermediate concentrations of the effector. Analysis of terminal phenotypes of the promoter-substituted cells in the presence of the antibiotic may facilitate functional analysis of essential orphan genes.