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Phosphatidylinositol 4,5-bisphosphate 3-kinases (PI3K) are a family of kinases whose activity affects pathways needed for basic cell functions. As a result, PI3K is one of the most mutated genes in all human cancers and serves as an ideal therapeutic target for cancer treatment. Expanding on work done by other groups we improved protein yield to produce stable and pure protein using a variety of modifications including improved solubility tag, novel expression modalities, and optimized purification protocol and buffer. By these means, we achieved a 40-fold increase in yield for p110α/p85α and a 3-fold increase in p110α. We also used these protocols to produce comparable constructs of the ß and δ isoforms of PI3K. Increased yield enhanced the efficiency of our downstream high throughput drug discovery efforts on the PIK3 family of kinases.

Asunto(s)

Fosfatidilinositol 3-Quinasa Clase I , Humanos , Fosfatidilinositol 3-Quinasa Clase I/genética , Fosfatidilinositol 3-Quinasa Clase I/metabolismo , Fosfatidilinositol 3-Quinasa Clase I/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/aislamiento & purificación , Fosfatidilinositol 3-Quinasa Clase Ia/genética , Fosfatidilinositol 3-Quinasa Clase Ia/química , Fosfatidilinositol 3-Quinasa Clase Ia/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Fosfatidilinositol 3-Quinasas/genética , Fosfatidilinositol 3-Quinasas/química , Solubilidad , Escherichia coli/genética , Escherichia coli/metabolismo

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Objective: PIK3CA-mutant non-small-cell lung cancer (NSCLC) is associated with other genetic mutations and may influence treatment strategies and clinical outcomes. We aimed to characterize PIK3CA mutations co-occurring with several major driver mutations using data from published cohorts and our medical center. Materials and Methods: We analyzed NSCLC patients harboring PIK3CA mutations from The Cancer Genome Atlas (TCGA) and Memorial Sloan Kettering (MSK) databases and retrospectively identified NSCLC patients with PIK3CA-mutants at a single medical center from our electronic records. The Log rank test was used to determine the association between PIK3CA mutations and overall survival (OS) in NSCLC patients. Results: Common hotspot mutations in PIK3CA were found in exon 9 (c.1633G > A, E545K, and c.1624G > A, E542K) and exon 20 (c.3140A > G, H1047R) in all cohorts. Co-occurring mutations of PIK3CA with EGFR, KRAS, and TP53 have been frequently observed in patients with NSCLC, with different percentages in these datasets generated by different background. PIK3CA mutations were observed to be significantly associated with poor OS in lung adenocarcinomas patients in the MSKCC cohort (hazard ratio [HR] = 0.519, 95% confidence interval [CI] = 0.301-0.896; P <0.05). Conclusion: PIK3CA co-occurring mutations in other genes may represent distinct subsets of NSCLC. Further elucidation of the roles of PIK3CA hotspot mutations combined with other driver mutations, including EGFR and KRAS, is needed to guide effective treatment in patients with advanced NSCLC.

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Objectives: Treatment of metastatic colorectal cancer (mCRC) includes resection of liver metastases (LM), however, no validated biomarker identifies patients most likely to benefit from this procedure. This meta-analysis aimed to assess the impact of the most relevant molecular alterations in cancer-related genes of CRC (i.e., RAS, BRAF, SMAD4, PIK3CA) as prognostic markers of survival and disease recurrence in patients with mCRC surgically treated by LM resection. Methods: A systematic literature review was performed to identify studies reporting data regarding survival and/or recurrence in patients that underwent complete liver resection for CRC LM, stratified according to RAS, BRAF, PIK3CA, and SMAD4 mutational status. Hazard ratios (HRs) from multivariate analyses were pooled in the meta-analysis and various adjustment strategies for confounding factors were combined. The search was conducted in numerous databases, including MEDLINE (PubMed), Embase, Cumulative Index to Nursing and Allied Health Literature (CINAHL) (EBSCO host), and WHO Global Index Medicus, through March 18th, 2022. Meta-analyses, editorials, letters to the editor, case reports, studies on other primary cancers, studies with primary metastatic sites other than the liver, studies lacking specific oncological outcome variables or genetic data, non-English language studies, and studies omitting residual disease data from liver metastasectomy were excluded. The remaining 47 studies were summarized in a descriptive table which outlines the key characteristics of each study and final results were graphically presented. Results: RAS mutation status was negatively associated with overall survival (OS) (HR, 1.68; 95% CI, 1.54-1.84) and recurrence free survival (RFS) (HR, 1.46; 95% CI, 1.33-1.61). A negative association was also found for BRAF regarding OS (HR, 2.64; 95% CI, 2.15-3.24) and RFS (HR, 1.89; 95% CI, 1.32-2.73) and SMAD4 regarding OS (HR, 1.93; 95% CI, 1.56-2.38) and RFS (HR, 1.95; 95% CI, 1.31-2.91). For PIK3CA only three studies were eligible and no significant association with either OS or RFS could be highlighted. Conclusion: RAS, BRAF, and SMAD4 are negatively associated with OS and RFS in patients undergoing curative liver metastasectomy from colorectal cancer. No conclusion can be drawn for PIK3CA due to the limited literature availability. These data support the integration of RAS, BRAF, and SMAD4 mutational status in the surgical decision-making for colorectal liver metastasis. Nevertheless, we have to consider several limitations, the major ones being the pooling of results from studies that evaluated patient outcomes as either disease-free survival (DFS) or RFS; the inclusion of patients with minimal residual disease and unconsidered potential confounding factors, such as variability in resectability definitions, chemotherapy use, and a potential interaction between biological markers and pre- and post-resection pharmacological treatments.

Asunto(s)

Neoplasias Colorrectales , Neoplasias Hepáticas , Mutación , Humanos , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/patología , Neoplasias Colorrectales/cirugía , Neoplasias Colorrectales/mortalidad , Neoplasias Hepáticas/secundario , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/cirugía , Neoplasias Hepáticas/mortalidad , Biomarcadores de Tumor/genética , Pronóstico , Hepatectomía/métodos , Proteínas Proto-Oncogénicas B-raf/genética , Fosfatidilinositol 3-Quinasa Clase I/genética , Proteína Smad4/genética , Recurrencia Local de Neoplasia/genética , Recurrencia Local de Neoplasia/patología , Recurrencia Local de Neoplasia/cirugía

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Breast cancer is a malignant tumor that poses a serious threat to women's health, and vasculogenic mimicry (VM) is strongly associated with bad prognosis in breast cancer. However, the relationship between VM and immune infiltration in breast cancer and the underlying mechanisms have not been fully studied. On the basis of the Cancer Genome Atlas (TCGA), Fudan University Shanghai Cancer Center (FUSCC) database, GSCALite database, and gene set enrichment analysis (GSEA) datasets, we investigated the potential involvement of VM-related genes in the development and progression of breast cancer. We analyzed the differential expression, mutation status, methylation status, drug sensitivity, tumor mutation burden (TMB), microsatellite instability (MSI), immune checkpoints, tumor microenvironment (TME), and immune cell infiltration levels associated with VM-related genes in breast cancer. We created two VM subclusters out of breast cancer patients using consensus clustering, and discovered that patients in Cluster 1 had better survival outcomes compared to those in Cluster 2. The infiltration levels of T cells CD4 memory resting and T cells CD8 were higher in Cluster 1, indicating an immune-active state in this cluster. Additionally, we selected three prognostic genes (LAMC2, PIK3CA, and TFPI2) using Lasso, univariate, and multivariate Cox regression and constructed a risk model, which was validated in an external dataset. The prognosis of patients is strongly correlated with aberrant expression of VM-related genes, which advances our knowledge of the tumor immune milieu and enables us to identify previously unidentified breast cancer subtypes. This could direct more potent immunotherapy approaches.

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Endometrial carcinomas (EC) of no special molecular profile (NSMP) represent the largest molecular category of EC, comprising a mixture of tumors with different histology and molecular profiles. These facts likely point to different tumor biology, clinical outcomes, and targeted therapy responses within this molecular category. The PIK3CA is currently the only targetable kinase oncoprotein directly implicated in EC carcinogenesis. Investigating a unique single-institution cohort, we attempted to stratify NSMP ECs based on the presence of the PIK3CA pathogenic mutation. Those cases were further analyzed for other well-established-associated oncogenic driver gene mutations. Histological and clinical variables were also correlated in each case. Altogether, 175 ECs were prospectively tested by a limited custom NGS panel containing ARID1A, BCOR, BRCA1, BRCA2, CTNNB1, KRAS, MLH1, MSH2, MSH6, NRAS, PIK3CA, PMS2, POLD1, POLE, PTEN,and TP53 genes. We identified 24 PIK3CA mutated cases in the group of 80 NSMP ECs, with another co-occurring mutation in at least one oncogenic driver gene (CTNNB1, PTEN, ARID1A, KRAS, BCOR, PMS2) in 19 cases. In conclusion, a limited NGS panel can effectively test EC tissue for specific pathogenetically relevant oncogene mutations. The NSMP EC category contains 30% of the PIK3CA mutated cases. Of those, 21% contain the PIK3CA mutation as a sole EC-associated oncogene mutation, while 79% harbor at least one more mutated gene. These findings may inform future healthcare planning and improve the effectiveness of EC patient selection for the PIK3CA-targeted therapy.

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INTRODUCTION: Hotspots (HS) mutations in the PIK3CA gene may lead to poorer oncological outcomes and endocrine resistance in advanced breast cancer (BC), but their prognostic role in early-stage disease remains controversial. The overall agreement within plasma and tissue methods has not been well explored. Our aim was to correlate tissue and plasma approaches and to analyze the prognostic impact of PIK3CA mutations (PIK3CAm) in HR+/HER2- BC. METHODS: A retrospective and unicentric analysis of PIK3CA mutational status in tissue and plasma samples by Cobas®PIK3CA Mutation Kit in patients with HR+/HER2- BC. RESULTS: We analyzed 225 samples from 161 patients with luminal BC. PIK3CA mutations were identified in 62 patients (38.5%), of which 39.6% were found in tissue and 11.8% in plasma. In advanced disease, plasma and tissue correlation rate was performed in 64 cases, with an overall agreement of 70.3%. Eighty patients were treated with CDK4/6 inhibitors + endocrine therapy. We observed a moderately worse progression-free survival (PFS) in PIK3CAm versus wild-type (WT) (24 m vs. 30 m; HR = 1.39, p = 0.26). A subanalysis was carried out based on exons 9 and 20, which showed a statistically poorer PFS in PIK3CAm exon 9 versus 20 population (9.7 m vs. 30.3 m; HR = 2.84; p = 0.024). Furthermore, detection of PIK3CAm in plasma was linked to a worse PFS vs PIK3CAm detection just in tissue (12.4 vs. 29.3; HR = 2.4; p = 0.08). CONCLUSIONS: Our findings suggest the PIK3CA evaluation in tissue as the diagnostic method of choice, however, additional investigations are required to improve the role of liquid biopsy in the PIK3CA assessment. PIK3CAm show worse outcomes in advanced luminal BC, especially in exon 9 mutation carriers, despite visceral involvement, prior exposure to endocrine therapy or detection of PIK3CAm in plasma, with an unclear prognosis in early-stage disease. Nonetheless, this should be validated in a prospective cohort study.

Asunto(s)

Biomarcadores de Tumor , Neoplasias de la Mama , Fosfatidilinositol 3-Quinasa Clase I , Mutación , Receptor ErbB-2 , Humanos , Fosfatidilinositol 3-Quinasa Clase I/genética , Femenino , Neoplasias de la Mama/genética , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/sangre , Neoplasias de la Mama/mortalidad , Neoplasias de la Mama/patología , Persona de Mediana Edad , Biomarcadores de Tumor/genética , Biomarcadores de Tumor/sangre , Pronóstico , Receptor ErbB-2/genética , Receptor ErbB-2/metabolismo , Anciano , Estudios Retrospectivos , Adulto , Anciano de 80 o más Años , Receptores de Progesterona/metabolismo , Receptores de Progesterona/genética , Receptores de Estrógenos/metabolismo

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The gene PIK3CA, encoding the catalytic subunit p110α of PI3Kα, is the second most frequently mutated gene in cancer, with the highest frequency oncogenic mutants occurring in the C-terminus of the kinase domain. The C-terminus has a dual function in regulating the kinase, playing a putative auto-inhibitory role for kinase activity and being absolutely essential for binding to the cell membrane. However, the molecular mechanisms by which these C-terminal oncogenic mutations cause PI3Kα overactivation remain unclear. To understand how a spectrum of C-terminal mutations of PI3Kα alter kinase activity compared to the WT, we perform unbiased and biased Molecular Dynamics simulations of several C-terminal mutants and report the free energy landscapes for the C-terminal "closed-to-open" transition in the WT, H1047R, G1049R, M1043L and N1068KLKR mutants. Results are consistent with HDX-MS experimental data and provide a molecular explanation why H1047R and G1049R reorient the C-terminus with a different mechanism compared to the WT and M1043L and N1068KLKR mutants. Moreover, we show that in the H1047R mutant, the cavity, where the allosteric ligands STX-478 and RLY-2608 bind, is more accessible contrary to the WT. This study provides insights into the molecular mechanisms underlying activation of oncogenic PI3Kα by C-terminal mutations and represents a valuable resource for continued efforts in the development of mutant selective inhibitors as therapeutics.

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Somatic activating mutations in PIK3CA are common drivers of vascular and lymphatic malformations. Despite common biophysical signatures of tissues susceptible to lesion formation, including compliant extracellular matrix and low rates of perfusion, lesions vary in clinical presentation from localized cystic dilatation to diffuse and infiltrative vascular dysplasia. The mechanisms driving the differences in disease severity and variability in clinical presentation and the role of the biophysical microenvironment in potentiating progression are poorly understood. Here, we investigate the role of hemodynamic forces and the biophysical microenvironment in the pathophysiology of vascular malformations, and we identify hemodynamic shear stress and defective endothelial cell mechanotransduction as key regulators of lesion progression. We found that constitutive PI3K activation impaired flow-mediated endothelial cell alignment and barrier function. We show that defective shear stress sensing in PIK3CA E542K endothelial cells is associated with reduced myosin light chain phosphorylation, junctional instability, and defective recruitment of vinculin to cell-cell junctions. Using 3D microfluidic models of the vasculature, we demonstrate that PIK3CA E542K microvessels apply reduced traction forces and are unaffected by flow interruption. We further found that draining transmural flow resulted in increased sprouting and invasion responses in PIK3CA E542K microvessels. Mechanistically, constitutive PI3K activation decreased cellular and nuclear elasticity resulting in defective cellular tensional homeostasis in endothelial cells which may underlie vascular dilation, tissue hyperplasia, and hypersprouting in PIK3CA-driven venous and lymphatic malformations. Together, these results suggest that defective nuclear mechanics, impaired cellular mechanotransduction, and maladaptive hemodynamic responses contribute to the development and progression of PIK3CA-driven vascular malformations.

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BACKGROUND: DEAD-box RNA helicase 19 A (DDX19A) is overexpressed in cervical squamous cell carcinoma. However, its role in gastric cancer remains unclear. The present study aimed to explore the role and underlying mechanism of DDX19A in the development of gastric cancer. METHODS: The expression of DDX19A in gastric cancer and paracancerous tissues was evaluated through quantitative polymerase chain reaction, western blotting, and immunohistochemical staining. The biological functions of DDX19A in gastric cancer were determined using CCK8, plate colony-forming, and Transwell migration assays. The specific mechanism of DDX19A in gastric cancer cells was studied using western blotting, RNA-binding protein immunoprecipitation, mRNA half-life detection, and nuclear and cytoplasmic RNA isolation. RESULTS: DDX19A was highly expressed in gastric cancer and positively associated with malignant clinicopathological features and poor prognosis. Additionally, DDX19A promoted gastric cancer cell proliferation, migration, and epithelial-mesenchymal transition phenotypes. Mechanistically, DDX19A activated the PI3K/AKT pathway by upregulating phosphatidylinositol-3-kinase (PIK3CA) expression. Furthermore, DDX19A interacted with PIK3CA mRNA, stabilized it, and facilitated its export from the nucleus. CONCLUSIONS: Our study reveals a novel mechanism whereby DDX19A promotes the proliferation and migration of gastric cancer cells by enhancing the stability and nuclear export of PIK3CA mRNA, thereby activating the PI3K/AKT pathway.

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Recent studies have revealed an association between TP53 mutations and endocrine resistance in hormone receptor-positive, HER2-negative breast cancer (HR + HER2 -BC). Aberrant p53 immunostaining (IHC) patterns may provide a surrogate marker for TP53 mutations. Building upon a ternary algorithm of aberrant staining patterns, this study evaluates the reliability of p53 IHC as screening tool for TP53 mutations in BC (NST). Furthermore, it describes the histopathological and molecular characteristics of TP53-mutated cases, along with the mutational status of PIK3CA. This study comprised 131 early-stage, node-negative BCs with available core biopsies and resection specimens. Cases were categorized as follows: HR + HER2 - (85 cases), HER2 + (21 cases) and triple negative (TN, 25 cases). Aberrant IHC staining patterns for p53 were defined as overexpression (OE), complete absence (CA) and cytoplasmic (CY). In addition, targeted sequencing of TP53 and PIK3CA genes was performed. TP53 mutations were identified in 53 of 126 cases (42.1%). Within HR + HER2 - cases, TP53 mutations were found in 17 of 80 cases (21.3%). IHC accurately predicted TP53 mutation in 96.2% of cases with a specificity of 100%. Additionally, there was a significant agreement between missense mutations and OE, as well as between truncating mutations and CA (κ 73% and 76%). CY was observed in two TN cases with truncating mutations within the nuclear localization signalling domain of p53. TP53-mutated cases exhibited higher grade, greater nuclear pleomorphism and higher Ki-67 proliferation index and were associated with the PIK3CA wild-type status (p < 0.001). p53 IHC may provide a useful screening tool for identifying TP53-mutated BC of NST.

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Phosphoinositide-3-kinases (PI3 K) are pivotal regulators of cell signaling implicated in various cancers. Particularly, mutations in the PIK3CA gene encoding the p110α catalytic subunit drive oncogenic signaling, making it an attractive therapeutic target. Our study conducted in silico exploration of 31 PIK3CA mutations across breast, endometrial, colon, and ovarian cancers, assessing their impacts on response to PI3Kα inhibitors and identifying potential non-toxic inhibitors and also elucidating their effects on protein stability and flexibility. Specifically, we observed significant alterations in the stability and flexibility of the PI3 K protein induced by these mutations. Through molecular docking analysis, we evaluated the binding interactions between the selected inhibitors and the PI3 K protein. The filtration of ligands involved calculating chemical descriptors, incorporating Veber and Lipinski rules, as well as IC50 values and toxicity predictions. This process reduced the initial dataset of 1394 ligands to 12 potential non-toxic inhibitors, and four reference inhibitors with significant biological activity in clinical trials were then chosen based on their physico-chemical properties. This analysis revealed Lig5's exceptional performance, exhibiting superior affinity and specificity compared to established reference inhibitors such as pictilisib. Lig5 formed robust binding interactions with the PI3 K protein, suggesting its potential as a highly effective therapeutic agent against PI3 K-driven cancers. Furthermore, molecular dynamics simulations provided valuable insights into Lig5's stability and its interactions with PI3 K over 100 ns. These simulations supported Lig5's potential as a versatile inhibitor capable of effectively targeting various mutational profiles of PI3 K, thereby mitigating issues related to resistance and toxicity commonly associated with current inhibitors.

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Introduction: Vascular anomalies (VAs) constitute a heterogeneous group of tumors and malformations capable of inducing significant clinical events in specific patients, such as the compression of vital organs, pain, functional impairment, or acquired coagulopathy. Molecular investigations into the underlying mechanisms of VAs have unveiled the frequent involvement of the PI3 K/AKT/mTOR pathway. Sirolimus, a specific mTOR inhibitor, has emerged as a potential therapeutic agent; however, its routine clinical application in complex VAs is currently restricted by a lack of extensive clinical experience. Methods: Between 2015 and 2024, we administered sirolimus to 14 pediatric patients with various types of vascular anomalies in two Italian centers, subjecting them to clinical and instrumental follow-up to investigate its efficacy and the possible occurrence of adverse events. Results: An overall improvement in or stability of their vascular anomalies was reported by 86% of patients. We also assessed toxicity, noting a low prevalence of life-threatening adverse events: only one case of sepsis was reported in a patient with a severe clinical condition, and four cases of recurrent aphthosis (28%) were reported. The most common side effect was dyslipidemia, with 43% of patients developing hypercholesterolemia (21%) or hypertriglyceridemia (21%), although these patients generally did not reach severe levels. Discussion: In line with data in the literature, according to our experience, medical therapy with sirolimus should be considered in pediatric patients affected by vascular anomalies.

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The incidence of thyroid cancer keeps rising and obesity emerges as an important risk factor for thyroid cancer, but the underlying mechanism is far from clear. Here, we hypothesize that leptin and insulin, two hormones closely related to obesity, may contribute to the pathogenesis of thyroid cancer. By using a combination of assays like CRISPR KO, cancer cell-T cell co-culture, ApoLive-Glo™ multiplex assay and syngeneic mouse model, we show that PD-L1 protein levels are increased dose-dependently by leptin or insulin in multiple thyroid cancer cell lines. Leptin and insulin converge to activate the PI3K-AKT pathway to enhance PD-L1 expression and activity. In addition, we use CRISPR KO to generate human thyroid cancer cells expressing WT PIK3CA or PIK3CA-E545K mutant. PIK3CA- E545K mutation makes the thyroid cancer cells to produce more PD-L1 protein upon leptin or insulin treatment. Thus, leptin and insulin synergize with PIK3CA mutation to enhance PD-L1 expression. Dual blockade of leptin and insulin signaling pathways reduces tumor size in a syngeneic mouse model. Our study suggests that understanding the interaction between genetic mutation and obesity is crucial for comprehensively assessing thyroid cancer risk and developing effective treatment strategies.

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BACKGROUND: Somatic mutations in the EGFR gene occur in about 50% of non-small cell lung cancers, with the T790M mutation significantly contributing to secondary resistance against EGFR-TKI drugs. However, EGFR T790M germline mutations rarely occur. CASE PRESENTATION: In this study, we report a case of a lung adenocarcinoma family lineage linked to a germline EGFR T790M mutation. The main subject was diagnosed with stage IV lung adenocarcinoma and experienced a 19-month period without disease progression while treated with Osimertinib. We collected both clinicopathological and familial data from a patient with lung adenocarcinoma. Next-generation sequencing of 40 key genes was performed on the proband's tumor tissue. To detect EGFR germline mutations, Sanger sequencing was conducted on peripheral blood mononuclear cells from the proband and his two daughters. Mutations such as EGFR T790M, EGFR 19-Del, TP53, and PIK3CA were identified in the proband's lung cancer tissue. Additionally, germline EGFR T790M mutations were confirmed in the proband and his daughters through sequencing of their peripheral blood samples. CT scans revealed multiple pulmonary nodules in both daughters. CONCLUSIONS: These observations suggest that germline mutations in EGFR T790M could be strongly linked to a familial predisposition to lung cancer.

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BACKGROUND: Alpelisib is an oral α-specific class I PI3K inhibitor approved in combination with fulvestrant for the treatment of PIK3CA-mutated hormone receptor-positive (HR+), human epidermal growth factor receptor 2 negative (HER2-) metastatic breast cancer. The tolerability of this drug with the oral chemotherapy capecitabine is unknown. PATIENTS AND METHODS: This phase I trial evaluated the dose-limiting toxicities (DLTs) and maximum tolerated dose (MTD) of alpelisib (250 mg or 300 mg daily for 3-weeks) with capecitabine (1000 mg/m2 twice daily for 2-weeks followed by a 1-week rest period) in patients with metastatic HER2-negative breast cancer, regardless of PIK3CA mutation status. RESULTS: Eighteen patients were treated with alpelisib-capecitabine. Half of the patients had HR+ breast cancer, and 16 had prior systemic therapy for metastatic disease. The MTD of alpelisib was 250 mg daily in combination with capecitabine 1000 mg/m2 twice daily. DLTs included hyperglycemia, QTc prolongation, fatigue, and chest pain. The most common grade 3 adverse event (AE) was hyperglycemia (28%). No grade 4 AEs were observed. Three patients discontinued therapy due to an AE. One-third of patients required dose reduction of both alpelisib and capecitabine. Four patients experienced a partial response and 8 patients experienced stable disease. The median progression-free survival was 9.7 months (95% CI 2.8-13.5 months) and median overall survival was 18.2 months (95% CI 7.2-35.2 months). Twelve patients had PIK3CA mutation testing completed, of these 2 had known or likely deleterious PIK3CA mutation. CONCLUSION: This study provides safety data for an oral combination therapy of alpelisib-capecitabine and defines tolerable doses for further study.

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Although anti-HER2 therapy has made significant strides in reducing metastasis and relapse in HER2-positive breast cancer, resistance to agents like trastuzumab, pertuzumab, and lapatinib frequently develops in patients undergoing treatment. Previous studies suggest that the hyperactivation of the PI3K-AKT signaling pathway by PIK3CA/PTEN gene mutations is implicated in HER2 resistance. In this study, we introduce a novel PI3K-p110α Proteolysis TAargeting Chimera (PROTAC) that effectively inhibits the proliferation of breast cancer cells by degrading PI3K-p110α. When tested in two lapatinib-resistant cell lines, JIMT1 and MDA-MB-453, both of which harbor PIK3CA mutations, the PI3K PROTAC notably reduced cell proliferation and induced G1 phase cell cycle arrest. Importantly, even at very low concentrations, PI3K PROTAC restored sensitivity to lapatinib. Furthermore, the efficacy of PI3K PROTAC surpassed that of Alpelisib, a selective PI3K-p110α kinase inhibitor in clinic. The superior performance of PI3K PROTAC was also confirmed in lapatinib-resistant breast cancer xenograft tumors and patient-derived breast cancer organoids (PDOs). In conclusion, this study reveals that the novel PI3K PROTAC we synthesized could serve as an effective agent to overcome lapatinib resistance.

Asunto(s)

Neoplasias de la Mama , Proliferación Celular , Fosfatidilinositol 3-Quinasa Clase I , Resistencia a Antineoplásicos , Lapatinib , Proteolisis , Receptor ErbB-2 , Ensayos Antitumor por Modelo de Xenoinjerto , Humanos , Lapatinib/farmacología , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/genética , Neoplasias de la Mama/patología , Femenino , Resistencia a Antineoplásicos/efectos de los fármacos , Fosfatidilinositol 3-Quinasa Clase I/genética , Fosfatidilinositol 3-Quinasa Clase I/metabolismo , Animales , Receptor ErbB-2/genética , Receptor ErbB-2/metabolismo , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Ratones , Proteolisis/efectos de los fármacos , Mutación , Antineoplásicos/farmacología , Inhibidores de Proteínas Quinasas/farmacología , Ratones Desnudos , Tiazoles

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Palmoplantar keratoderma (PPK) is a group of -disorders with genetic and phenotypic heterogeneity featuring skin thickening of the palms and soles. More than 60 genes involved in various biological processes are implicated in PPK. PIK3CA is an oncogene encoding p110α, and its somatic variants contribute to a spectrum of congenital overgrowth disorders, including epidermal nevi (EN). To identify the genetic basis and elucidate the pathogenesis of a patient with unilateral focal PPK. Whole-exome sequencing and Sanger sequencing combined with laser capture microdissection (LCM) were performed on genomic DNA extracted from the patient's peripheral blood and skin lesion. Skin biopsies were taken from the lesion of the patient and normal controls for immunofluorescence. Molecular docking was performed using Alphafold2-multimer. A three-year-old girl presented with unilateral focal PPK with an identified missense -variant (c.3140A>G, p.His1047Arg) in PIK3CA from affected tissue. This variant only existed in the lesional epidermis. Elevated PI3K/AKT/mTOR signalling in the affected epidermis and an increased number of Ki67-positive keratinocytes were demonstrated. Molecular docking indicated instability of the p110α-p85α dimer caused by the PIK3CA His1047Arg variant. We describe the first PPK case associated with a variant in PIK3CA, which expands the spectrum of PIK3CA-related disorders. Our study further underscores the importance of the PI3K/AKT/mTOR pathway in the homeostasis of skin keratinization.

Asunto(s)

Fosfatidilinositol 3-Quinasa Clase I , Queratodermia Palmoplantar , Mutación Missense , Transducción de Señal , Preescolar , Femenino , Humanos , Fosfatidilinositol 3-Quinasa Clase I/genética , Secuenciación del Exoma , Queratodermia Palmoplantar/genética , Queratodermia Palmoplantar/patología , Proteínas Proto-Oncogénicas c-akt/genética , Proteínas Proto-Oncogénicas c-akt/metabolismo , Transducción de Señal/genética , Serina-Treonina Quinasas TOR/genética , Serina-Treonina Quinasas TOR/metabolismo

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PIK3CA-related overgrowth spectrum (PROS) is an umbrella term to describe a diverse range of developmental disorders. Research to date has predominantly emerged from Europe and North America, resulting in a notable scarcity of studies focusing on East Asian populations. Currently, the prevalence and distribution of PIK3CA variants across various genetic loci and their correlation with distinct phenotypes in East Asian populations remain unclear. This study aims to elucidate the phenotype-genotype correlations of PROS in East Asian populations. We presented the phenotypes and genotypes of 82 Chinese patients. Among our cohort, 67 individuals carried PIK3CA variants, including missense, frameshift, and splice variants. Six patients presented with both PIK3CA and an additional variant. Seven PIK3CA-negative patients exhibited overlapping PROS manifestations with variants in GNAQ, AKT1, PTEN, MAP3K3, GNA11, or KRAS. An integrative review of the literature pertaining to East Asian populations revealed that specific variants are uniquely associated with certain PROS phenotypes. Some rare variants were exclusively identified in cases of megalencephaly and diffuse capillary malformation with overgrowth. Non-hotspot variants with undefined oncogenicity were more common in CNS phenotypes. Diseases with vascular malformation were more likely to have variants in the helical domain, whereas phenotypes involving adipose/muscle overgrowth without vascular abnormalities predominantly presented variants in the C2 domain. Our findings underscore the unique phenotype-genotype patterns within the East Asian PROS population, highlighting the necessity for an expanded cohort to further elucidate these correlations. Such endeavors would significantly facilitate the development of PI3Kα selective inhibitors tailored for the East Asian population in the future.

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Pueblo Asiatico , Fosfatidilinositol 3-Quinasa Clase I , Genotipo , Fenotipo , Adolescente , Niño , Preescolar , Femenino , Humanos , Lactante , Masculino , Asia Oriental , Pueblo Asiatico/genética , Fosfatidilinositol 3-Quinasa Clase I/genética , Pueblos del Este de Asia , Estudios de Asociación Genética , Trastornos del Crecimiento/genética , Trastornos del Crecimiento/patología , Mutación

RESUMEN

Introduction: Mesenchymal stem cells can develop into osteoblasts, making them a promising cell-based osteoporosis treatment. Despite their therapeutic potential, their molecular processes are little known. Bioinformatics and experimental analysis were used to determine the molecular processes of bone marrow mesenchymal stem cell (BMSC) therapy for postmenopausal osteoporosis (PMO). Material and methods: We used weighted gene co-expression network analysis (WGCNA) to isolate core gene sets from two GEO microarray datasets (GSE7158 and GSE56815). GeneCards found PMO-related genes. GO, KEGG, Lasso regression, and ROC curve analysis refined our candidate genes. Using the GSE105145 dataset, we evaluated KLF2 expression in BMSCs and examined the link between KLF2 and PIK3CA using Pearson correlation analysis. We created a protein-protein interaction network of essential genes involved in osteoblast differentiation and validated the functional roles of KLF2 and PIK3CA in BMSC osteoblast differentiation in vitro. Results: We created 6 co-expression modules from 10 419 differentially expressed genes (DEGs). PIK3CA, the key gene in the PI3K-Akt pathway, was among 197 PMO-associated DEGs. KLF2 also induced PIK3CA transcription in PMO. BMSCs also expressed elevated KLF2. BMSC osteoblast differentiation involved the PI3K-Akt pathway. In vitro, KLF2 increased PIK3CA transcription and activated the PI3K-Akt pathway to differentiate BMSCs into osteoblasts. Conclusions: BMSCs release KLF2, which stimulates the PIK3CA-dependent PI3K-Akt pathway to treat PMO. Our findings illuminates the involvement of KLF2 and the PI3K-Akt pathway in BMSC osteoblast development, which may lead to better PMO treatments.