AZD8186 in Combination With Paclitaxel in Patients With Advanced Gastric Cancer: Results From a Phase Ib/II Study (KCSG ST18-20)

PI3Kδ as a Novel Therapeutic Target for Aggressive Prostate Cancer

Phosphoinositide 3-kinases (PI3Ks) signaling represents an important pathway regulating cell proliferation, survival, invasion, migration, and metabolism. Notably, PI3K/AKT/mTOR signaling is frequently dysregulated in the majority of malignancies. Among the class IA PI3Ks (PI3Kα/β/δ), emerging evidence has implicated that PI3Kδ is not only overexpressed in leukocytes but also in solid tumors, including prostate cancer. The critical role of PI3Kδ in tumorigenesis and in the creation of a suppressive tumor microenvironment, along with the recent finding of PI3Kδ splice isoforms in promoting tumor aggressiveness and resistance, further demonstrates the potential of developing novel PI3Kδ-targeted cancer therapies. In this review, we comprehensively describe the functional mechanisms underlying the PI3Kδ-driven tumor progression and immune regulation in prostate cancer diseases. Furthermore, the recent preclinical and clinical studies on the development of PI3Kδ-/PI3K-targeted inhibitors as single agents and in combination therapies (with chemotherapy, radiation, hormone therapy, or immunotherapy) are summarized. Finally, we discuss the potential novel therapies for improving the treatment efficacies, as well as the current limitations and challenges of PI3Kδ-based therapies for prostate cancer.

Comprehensive analysis and experimental validation of disulfidptosis-associated prognostic signature and immune microenvironment characterization of gastric cancer

BACKGROUND

Gastric cancer (GC) is one of the most common causes of cancer-related death worldwide. As a novel form of programmed cell death, disulfidptosis is characterized by excessive cysteine accumulation, disulfide stress and actin destruction. There is evidence that targeting disulfidptosis is a promising anticancer strategy. Further improvement of GC risk stratification based on disulfidptosis has positive clinical significance.

METHODS

We analyzed the expression levels of disulfidptosis-associated genes (DPAGs) in normal and GC tissues and characterized the molecular subtypes of GC patients. Based on the characteristics of DPAG subtypes, differentially expressed prognosis-related genes were selected by LASSO-univariate Cox analysis and multivariate Cox analysis analyzed to establish a prognostic model. Using single-cell sequencing analysis reveals the cell subpopulation for GC. The function of the selected target in GC was verified by in vitro experimental means, including siRNA, qRT-PCR, Western blot, CCK-8, and Transwell assay.

RESULTS

DPAG score was verified to be an independent prognostic factor of GC and was significantly associated with poor prognosis of gastric cancer. Subsequent studies on subgroup immunoinfiltration characteristics, drug sensitivity analysis, immunotherapy response and somatic mutation characteristics of DPAG score comprehensively confirmed the potential guiding significance of DPAG score for individualized treatment of gastric cancer patients. Single-cell sequencing analysis revealed the expression characteristics of DPAG-related prognostic signatures across cell subpopulations. In vitro experiments showed APC11, as one of the selected DPAGs, was highly expressed in gastric cancer, and knockdown of APC11 could significantly inhibit the proliferation and migration of GC cells, demonstrating the reliability of bioinformatics results.

CONCLUSION

The results of this study provide a new perspective for exploring the role of disulfidptosis in the occurrence and development of GC.

A bibliometric analysis of the application of the PI3K-AKT-mTOR signaling pathway in cancer

PI3K-AKT-mTOR plays as important role in the growth, metabolism, proliferation, and migration of cancer cells, and in apoptosis, autophagy, inflammation, and angiogenesis in cancer. In this study, the aim was to comprehensively review the current research landscape regarding the PI3K-AKT-mTOR pathway in cancer, using bibliometrics to analyze research hotspots, and provide ideas for future research directions. Literature published on the topic between January 2006 and May 2023 was retrieved from the Web of Science core database, and key information and a visualization map were analyzed using CiteSpace and VOSviewer. A total of 5800 articles from 95 countries/regions were collected, including from China and the USA. The number of publications on the topic increased year on year. The major research institution was the University of Texas MD Anderson Cancer Center. Oncotarget and Clinical Cancer Research were the most prevalent journals in the field. Of 26,621 authors, R Kurzrock published the most articles, and J Engelman was cited most frequently. "A549 cell," "first line treatment," "first in human phase I," and "inhibitor" were the keywords of emerging research hotspots. Inhibitors of the PI3K-AKT-mTOR pathway and their use in clinical therapeutic strategies for cancer were the main topics in the field, and future research should also focus on PI3K-AKT-mTOR pathway inhibitors. This study is the first to comprehensively summarize trends and development s in research into the PI3K-AKT-mTOR pathway in cancer. The information that was obtained clarified recent research frontiers and directions, providing references for scholars of cancer management.

A novel model based on protein post-translational modifications comprising the immune landscape and prediction of colorectal cancer prognosis

Background

Phosphorylation is a critical post-translational modification (PTM) type contributing to colorectal cancer (CRC). The study aimed to construct a nomogram model to predict colon adenocarcinoma (COAD) prognosis based on PTM signatures.

Methods

The Cancer Genome Atlas (TCGA) database has been indexed for COAD patients' RNA sequencing, proteomic data, and clinical details. To find potential PTM prognostic signatures, the least absolute shrinkage and selection operator (LASSO) was deployed. Model validation procedures included the use of the Kaplan-Meier (K-M) method, the receiver operating characteristic (ROC) curve, the area under the curve (AUC), and the decision curve analysis (DCA). Additionally, biological enrichment, tumor immune microenvironment, and chemotherapy were also assessed. To validate the model, CRC cells were used in in vitro experiments using western blotting, proliferation assay, colony formation assay, and flow cytometry.

Results

The LASSO regression analysis identified 8 PTM sites. Based on the median PTM score, patients were classified into low- and high-risk groups. K-M results showed that high-risk patients had worse prognoses (P<0.001). Our model demonstrated powerful effectiveness and predictive value (TCGA whole group: 1-year AUC =0.611, 2-year AUC =0.574, 3-year AUC =0.627). Additionally, high-risk CRC patients were enriched in KRAS signaling pathways (P=0.01), possessed more robust immune escape capacity (P=0.001, and induced cell-cycle arrest of CRC cells (P<0.01).

Conclusions

We established and validated a novel nomogram model related to PTM that can predict prognosis and guide the treatment of COAD.

Targeting PI3K family with small-molecule inhibitors in cancer therapy: current clinical status and future directions

The Phosphatidylinositol-3-kinase (PI3K) family is well-known to comprise three classes of intracellular enzymes. Class I PI3Ks primarily function in signaling by responding to cell surface receptor stimulation, while class II and III are more involved in membrane transport. Under normal physiological conditions, the PI3K signaling network orchestrates cell growth, division, migration and survival. Aberrant activation of the PI3K signaling pathway disrupts cellular activity and metabolism, often marking the onset of cancer. Currently, the Food and Drug Administration (FDA) has approved the clinical use of five class I PI3K inhibitors. These small-molecule inhibitors, which exhibit varying selectivity for different class I PI3K family members, are primarily used in the treatment of breast cancer and hematologic malignancies. Therefore, the development of novel class I PI3K inhibitors has been a prominent research focus in the field of oncology, aiming to enhance potential therapeutic selectivity and effectiveness. In this review, we summarize the specific structures of PI3Ks and their functional roles in cancer progression. Additionally, we critically evaluate small molecule inhibitors that target class I PI3K, with a particular focus on their clinical applications in cancer treatment. Moreover, we aim to analyze therapeutic approaches for different types of cancers marked by aberrant PI3K activation and to identify potential molecular targets amenable to intervention with small-molecule inhibitors. Ultimately, we propose future directions for the development of therapeutic strategies that optimize cancer treatment outcomes by modulating the PI3K family.

Dissecting gastric cancer heterogeneity and exploring therapeutic strategies using bulk and single-cell transcriptomic analysis and experimental validation of tumor microenvironment and metabolic interplay

Gastric cancer, the fifth most prevalent cancer worldwide, is often diagnosed in advanced stages with limited treatment options. Examining the tumor microenvironment (TME) and its metabolic reprogramming can provide insights for better diagnosis and treatment. This study investigates the link between TME factors and metabolic activity in gastric cancer using bulk and single-cell RNA-sequencing data. We identified two molecular subtypes in gastric cancer by analyzing the distinct expression patterns of 81 prognostic genes related to the TME and metabolism, which exhibited significant protein-level interactions. The high-risk subtype had increased stromal content, fibroblast and M2 macrophage infiltration, elevated glycosaminoglycans/glycosphingolipids biosynthesis, and fat metabolism, along with advanced clinicopathological features. It also exhibited low mutation rates and microsatellite instability, associating it with the mesenchymal phenotype. In contrast, the low-risk group showed higher tumor content and upregulated protein and sugar metabolism. We identified a 15-gene prognostic signature representing these characteristics, including CPVL, KYNU, CD36, and GPX3, strongly correlated with M2 macrophages, validated through single-cell analysis and an internal cohort. Despite resistance to immunotherapy, the high-risk group showed sensitivity to molecular targeted agents directed at IGF-1R (BMS-754807) and the PI3K-mTOR pathways (AZD8186, AZD8055). We experimentally validated these promising drugs for their inhibitory effects on MKN45 and MKN28 gastric cells. This study unveils the intricate interplay between TME and metabolic pathways in gastric cancer, offering potential for enhanced diagnosis, patient stratification, and personalized treatment. Understanding molecular features in each subtype enriches our comprehension of gastric cancer heterogeneity and potential therapeutic targets.

Identification of neutrophil extracellular trap-driven gastric cancer heterogeneity and C5AR1 as a therapeutic target

Neutrophil extracellular traps (NETs) are implicated in gastric cancer (GC) growth, metastatic dissemination, cancer-associated thrombosis, etc. This work is conducted to elucidate the heterogeneity of NETs in GC. The transcriptome heterogeneity of NETs is investigated in TCGA-STAD via a consensus clustering algorithm, with subsequent external verification in the GSE88433 and GSE88437 cohorts. Clinical and molecular traits, the immune microenvironment, and drug response are characterized in the identified NET-based clusters. Based upon the feature genes of NETs, a classifier is built for estimating NET-based clusters via machine learning. Multiple experiments are utilized to verify the expressions and implications of the feature genes in GC. A novel NET-based classification system is proposed for reflecting the heterogeneity of NETs in GC. Two NET-based clusters have unique and heterogeneous clinical and molecular features, immune microenvironments, and responses to targeted therapy and immunotherapy. A logistic regression model reliably differentiates the NET-based clusters. The feature genes C5AR1, CSF1R, CSF2RB, CYBB, HCK, ITGB2, LILRB2, MNDA, MPEG1, PLEK, SRGN, and STAB1 are proven to be aberrantly expressed in GC cells. Specific knockdown of C5AR1 effectively hinders GC cell growth and elicits intracellular ROS accumulation. In addition, its suppression suppresses the aggressiveness and EMT phenotype of GC cells. In all, NETs are the main contributors to intratumoral heterogeneity and differential drug sensitivity in GC, and C5AR1 has been shown to trigger GC growth and metastatic spread. These findings collectively provide a theoretical basis for the use of anti-NETs in GC treatment.

Molecular Targeting of the Phosphoinositide-3-Protein Kinase (PI3K) Pathway across Various Cancers

The dysregulation of the phosphatidylinositol-3-kinase (PI3K) pathway can lead to uncontrolled cellular growth and tumorigenesis. Targeting PI3K and its downstream substrates has been shown to be effective in preclinical studies and phase III trials with the approval of several PI3K pathway inhibitors by the Food and Drug Administration (FDA) over the past decade. However, the limited clinical efficacy of these inhibitors, intolerable toxicities, and acquired resistances limit the clinical application of PI3K inhibitors. This review discusses the PI3K signaling pathway, alterations in the PI3K pathway causing carcinogenesis, current and novel PI3K pathway inhibitors, adverse effects, resistance mechanisms, challenging issues, and future directions of PI3K pathway inhibitors.

Development of small-molecule inhibitors that target PI3Kβ

Phosphatidylinositol-3 kinase (PI3K) β, a subtype of class I PI3Ks, has an essential role in PTEN-deficient tumors and links to thrombosis, male fertility, and Fragile X syndrome. PI3Kβ-specific targeting therapy could be an efficacious treatment for diseases highly dependent on PI3Kβ, while mitigating the severe toxicity of pan-PI3K inhibitors. Achieving selectivity can be accomplished through three primary strategies, namely, binding to the induced lipophilic pocket, targeting the unique amino acid residue of PI3Kβ, or using atropisomerism to lock conformation. In this review, we focus on advances in the development of these β-isoform-selective PI3K inhibitors, providing potential guidance for the further development of novel clinical candidates.

Effects of polymer terminal group inside micelle core on paclitaxel loading promoting and burst release suppressing

Background

Paclitaxel (PTX) is widely used in the treatment of advanced esophageal and gastric cancer. Polymeric micelles can improve the drug-loading efficiency of PTX. However, the end groups on the amphiphilic blocks affect the drug-loading efficiency and the release kinetics of polymeric micelles. Therefore, there is an urgent need to disclose the tailoring of the core-/shell-forming terminal groups.

Methods

Different from the conventional block copolymer synthesis in the reversible addition-fragmentation chain-transfer polymerization, which has a hydrophilic end group on the core-forming blocks, an alternative monomer addition method was applied to tune and obtain two block copolymers with symmetrical and similar block length PBMAn-b-PNAMm [PNAM, poly(N-acryloylmorpholine); PBMA, poly(n-butyl methacrylate)] but distinct end groups on the hydrophobic core-forming blocks, that is, HOOC-PBMA-PNAM-Phen and HOOC-PNAM-PBMA-Phen. The chemical structure of the resulting copolymers was elucidated by proton nuclear magnetic resonance spectroscopy and differential scanning calorimetry. The spherical morphology revealed by transmission electron microscopy and the uniform particle size revealed by dynamic light scattering analysis clearly confirmed the successful preparation of a PTX-polymeric micelle complex.

Results

The particle sizes of HOOC-PBMA-PNAM-Phen and HOOC-PNAM-PBMA-Phen were about 40 and 235 nm respectively. The PTX loading efficiency of HOOC-PBMA-PNAM-Phen was much lower than that of HOOC-PNAM-PBMA-Phen. The PTX release from HOOC-PBMA-PNAM-Phen was much slower than that of HOOC-PNAM-PBMA-Phen. The polymers had glass transition temperature (Tg) values of 70.24 and 74.22 ℃, which was from the HOOC-PBMA-PNAM-Phen and HOOC-PNAM-PBMA-Phen micelles, respectively. The systematic study on the PTX loading and releasing profile disclosed that, compared with the HOOC-PBMA-PNAM-Phen, the micelles with Phen group on the hydrophobic block (HOOC-PNAM-PBMA-Phen) enhanced drug loading and prolonged drug release but with a larger particle size.

Conclusions

The results indicated that the hydrophobic end group Phen on the core-forming blocks can promote hydrophobic drug loading and suppress burst release.