Lack of Laminar Shear Stress Facilitates the Endothelial Uptake of Very Small Superparamagnetic Iron Oxide Nanoparticles by Modulating the Endothelial Surface Layer.

Purpose: To study whether the absence of laminar shear stress (LSS) enables the uptake of very small superparamagnetic iron oxide nanoparticles (VSOP) in endothelial cells by altering the composition, size, and barrier function of the endothelial surface layer (ESL). Methods and Results: A quantitative particle exclusion assay with living human umbilical endothelial cells using spinning disc confocal microscopy revealed that the dimension of the ESL was reduced in cells cultivated in the absence of LSS. By combining gene expression analysis, flow cytometry, high pressure freezing/freeze substitution immuno-transmission electron microscopy, and confocal laser scanning microscopy, we investigated changes in ESL composition. We found that increased expression of the hyaluronan receptor CD44 by absence of shear stress did not affect the uptake rate of VSOPs. We identified collagen as a previously neglected component of ESL that contributes to its barrier function. Experiments with inhibitor halofuginone and small interfering RNA (siRNA) demonstrated that suppression of collagen expression facilitates VSOP uptake in endothelial cells grown under LSS. Conclusion: The absence of laminar shear stress disturbs the barrier function of the ESL, facilitating membrane accessibility and endocytic uptake of VSOP. Collagen, a previously neglected component of ESL, contributes to its barrier function.

Discovery of tetrazolo-pyridazine-based small molecules as inhibitors of MACC1-driven cancer metastasis.

Metastasis is directly linked to poor prognosis of cancer patients and warrants search for effective anti-metastatic drugs. MACC1 is a causal key molecule for metastasis. High MACC1 expression is prognostic for metastasis and poor survival. Here, we developed novel small molecule inhibitors targeting MACC1 expression to impede metastasis formation. We performed a human MACC1 promoter-driven luciferase reporter-based high-throughput screen (HTS; 118.500 compound library) to identify MACC1 transcriptional inhibitors. HTS revealed 1,2,3,4-tetrazolo[1,5-b]pyridazine-based compounds as efficient transcriptional inhibitors of MACC1 expression, able to decrease MACC1-induced cancer cell motility in vitro. Structure-activity relationships identified the essential inhibitory core structure. Best candidates were evaluated for metastasis inhibition in xenografted mouse models demonstrating metastasis restriction. ADMET showed high drug-likeness of these new candidates for cancer therapy. The NFκB pathway was identified as one mode of action targeted by these compounds. Taken together, 1,2,3,4-tetrazolo[1,5-b]pyridazine-based compounds are effective MACC1 inhibitors and pose promising candidates for anti-metastatic therapies particularly for patients with MACC1-overexpressing cancers, that are at high risk to develop metastases. Although further preclinical and clinical development is necessary, these compounds represent important building blocks for an individualized anti-metastatic therapy for solid cancers.

Transporters, TBC1D4, and ARID5B Variants to Explain Glycated Hemoglobin Variability in Patients with Type 2 Diabetes.

INTRODUCTION: Genetic variants could aid in predicting antidiabetic drug response by associating them with markers of glucose control, such as glycated hemoglobin (HbA1c). However, pharmacogenetic implementation for antidiabetics is still under development, as the list of actionable markers is being populated and validated. This study explores potential associations between genetic variants and plasma levels of HbA1c in 100 patients under treatment with metformin. METHODS: HbA1c was measured in a clinical chemistry analyzer (Roche), genotyping was performed in an Illumina-GSA array and data were analyzed using PLINK. Association and prediction models were developed using R and a 10-fold cross-validation approach. RESULTS: We identified genetic variants on SLC47A1, SLC28A1, ABCG2, TBC1D4, and ARID5B that can explain up to 55% of the interindividual variability of HbA1c plasma levels in diabetic patients under treatment. Variants on SLC47A1, SLC28A1, and ABCG2 likely impact the pharmacokinetics (PK) of metformin, while the role of the two latter can be related to insulin resistance and regulation of adipogenesis. CONCLUSIONS: Our results confirm previous genetic associations and point to previously unassociated gene variants for metformin PK and glucose control.

Complete screening of exons 2, 3, and 4 of kras and nras genes reveals a higher number of clinically relevant mutations than food and drug administration quantitative polymerase chain reaction-based commercial kits

Abstract Background: The presence of clinically relevant mutations in KRAS and NRAS genes determines the response of anti-epidermal growth factor receptor antibody therapy for metastatic colorectal cancer (mCRC). The only quantitative polymerase chain reaction (qPCR)-based diagnostic tests approved by the Food and Drug Administration (FDA) screen merely for mutations in codons 12 and 13 of KRAS. Objective: The objective of the study was to study the frequency of clinically relevant mutations in KRAS and NRAS genes that are not included in FDA-approved qPCR tests. Methods: Formalin-fixed paraffin-embedded tumor specimens from 1113 mCRC Mexican patients from different health institutions across the country were analyzed by Sanger sequencing for KRAS mutations in exons 2, 3, and 4. Furthermore, 83 were analyzed in exons 2, 3, and 4 of NRAS. Results: From the specimens tested for KRAS, 33.69% harbored a mutation. From these, 71.77% were in codon 12 and 27.69% in codon 13 (both located in exon 2). Codons 59 (exon 3) and 146 (exon 4) accounted for the remaining 0.54%. From the 83 specimens, in which NRAS was analyzed, three mutations were found in codon 12 (3.61%). Approximately 6% of RAS mutated specimens would have been falsely reported as RAS wild type if an FDA-approved qPCR diagnostic test had been used. Conclusions: While these kits based on qPCR can be very practical and highly sensitive, their mutation coverage ignores mutations from poorly genetically characterized populations.

Complete Screening of Exons 2, 3, and 4 of KRAS and NRAS Genes Reveals a Higher Number of Clinically Relevant Mutations than Food and Drug Administration Quantitative Polymerase Chain Reaction-Based Commercial Kits.

BACKGROUND: The presence of clinically relevant mutations in KRAS and NRAS genes determines the response of anti-epidermal growth factor receptor antibody therapy for metastatic colorectal cancer (mCRC). The only quantitative polymerase chain reaction (qPCR)-based diagnostic tests approved by the Food and Drug Administration (FDA) screen merely for mutations in codons 12 and 13 of KRAS. OBJECTIVE: The objective of the study was to study the frequency of clinically relevant mutations in KRAS and NRAS genes that are not included in FDA-approved qPCR tests. METHODS: Formalin-fixed paraffin-embedded tumor specimens from 1113 mCRC Mexican patients from different health institutions across the country were analyzed by Sanger sequencing for KRAS mutations in exons 2, 3, and 4. Furthermore, 83 were analyzed in exons 2, 3, and 4 of NRAS. RESULTS: From the specimens tested for KRAS, 33.69% harbored a mutation. From these, 71.77% were in codon 12 and 27.69% in codon 13 (both located in exon 2). Codons 59 (exon 3) and 146 (exon 4) accounted for the remaining 0.54%. From the 83 specimens, in which NRAS was analyzed, three mutations were found in codon 12 (3.61%). Approximately 6% of RAS mutated specimens would have been falsely reported as RAS wild type if an FDA-approved qPCR diagnostic test had been used. CONCLUSIONS: While these kits based on qPCR can be very practical and highly sensitive, their mutation coverage ignores mutations from poorly genetically characterized populations.

KRAS, NRAS, and BRAF mutation prevalence, clinicopathological association, and their application in a predictive model in Mexican patients with metastatic colorectal cancer: A retrospective cohort study.

Mutations in KRAS, NRAS, and BRAF (RAS/BRAF) genes are the main predictive biomarkers for the response to anti-EGFR monoclonal antibodies (MAbs) targeted therapy in metastatic colorectal cancer (mCRC). This retrospective study aimed to report the mutational status prevalence of these genes, explore their possible associations with clinicopathological features, and build and validate a predictive model. To achieve these objectives, 500 mCRC Mexican patients were screened for clinically relevant mutations in RAS/BRAF genes. Fifty-two percent of these specimens harbored clinically relevant mutations in at least one screened gene. Among these, 86% had a mutation in KRAS, 7% in NRAS, 6% in BRAF, and 2% in both NRAS and BRAF. Only tumor location in the proximal colon exhibited a significant correlation with KRAS and BRAF mutational status (p-value = 0.0414 and 0.0065, respectively). Further t-SNE analyses were made to 191 specimens to reveal patterns among patients with clinical parameters and KRAS mutational status. Then, directed by the results from classical statistical tests and t-SNE analysis, neural network models utilized entity embeddings to learn patterns and build predictive models using a minimal number of trainable parameters. This study could be the first step in the prediction for RAS/BRAF mutational status from tumoral features and could lead the way to a more detailed and more diverse dataset that could benefit from machine learning methods.

Genotypic and Phenotypic Factors Influencing Drug Response in Mexican Patients With Type 2 Diabetes Mellitus.

The treatment of Type 2 Diabetes Mellitus (T2DM) consists primarily of oral antidiabetic drugs (OADs) that stimulate insulin secretion, such as sulfonylureas (SUs) and reduce hepatic glucose production (e.g., biguanides), among others. The marked inter-individual differences among T2DM patients' response to these drugs have become an issue on prescribing and dosing efficiently. In this study, fourteen polymorphisms selected from Genome-wide association studies (GWAS) were screened in 495 T2DM Mexican patients previously treated with OADs to find the relationship between the presence of these polymorphisms and response to the OADs. Then, a novel association screening method, based on global probabilities, was used to globally characterize important relationships between the drug response to OADs and genetic and clinical parameters, including polymorphisms, patient information, and type of treatment. Two polymorphisms, ABCC8-Ala1369Ser and KCNJ11-Glu23Lys, showed a significant impact on response to SUs. Heterozygous ABCC8-Ala1369Ser variant (A/C) carriers exhibited a higher response to SUs compared to homozygous ABCC8-Ala1369Ser variant (A/A) carriers (p-value = 0.029) and to homozygous wild-type genotypes (C/C) (p-value = 0.012). The homozygous KCNJ11-Glu23Lys variant (C/C) and wild-type (T/T) genotypes had a lower response to SUs compared to heterozygous (C/T) carriers (p-value = 0.039). The screening of OADs response related genetic and clinical factors could help improve the prescribing and dosing of OADs for T2DM patients and thus contribute to the design of personalized treatments.