DTX3L Accelerates Pancreatic cancer Progression via FAK/PI3K/AKT Axis

RGS4 promotes the progression of gastric cancer through the focal adhesion kinase/phosphatidyl-inositol-3-kinase/protein kinase B pathway and epithelial-mesenchymal transition

BACKGROUND

Regulator of G protein signaling (RGS) proteins participate in tumor formation and metastasis by acting on the α-subunit of heterotrimeric G proteins. The specific effect of RGS, particularly RGS4, on the progression of gastric cancer (GC) is not yet clear.

AIM

To explore the role and underlying mechanisms of action of RGS4 in GC development.

METHODS

The prognostic significance of RGS4 in GC was analyzed using bioinformatics based public databases and verified by immunohistochemistry and quantitative polymerase chain reaction in 90 patients with GC. Function assays were employed to assess the carcinogenic impact of RGS4, and the mechanism of its possible influence was detected by western blot analysis. A nude mouse xenograft model was established to study the effects of RGS4 on GC growth in vitro.

RESULTS

RGS4 was highly expressed in GC tissues compared with matched adjacent normal tissues. Elevated RGS4 expression was correlated with increased tumor-node-metastasis stage, increased tumor grade as well as poorer overall survival in patients with GC. Cell experiments demonstrated that RGS4 knockdown suppressed GC cell proliferation, migration and invasion. Similarly, xenograft experiments confirmed that RGS4 silencing significantly inhibited tumor growth. Moreover, RGS4 knockdown resulted in reduced phosphorylation levels of focal adhesion kinase, phosphatidyl-inositol-3-kinase, and protein kinase B, decreased vimentin and N-cadherin, and elevated E-cadherin.

CONCLUSION

High RGS4 expression in GC indicates a worse prognosis and RGS4 is a prognostic marker. RGS4 influences tumor progression via the focal adhesion kinase/phosphatidyl-inositol-3-kinase/protein kinase B pathway and epithelial-mesenchymal transition.

Spatial transcriptome profiling identifies DTX3L and BST2 as key biomarkers in esophageal squamous cell carcinoma tumorigenesis

BACKGROUND

Understanding the stepwise progression of esophageal squamous cell carcinoma (ESCC) is crucial for developing customized strategies for early detection and optimal clinical management. Herein, we aimed to unravel the transcriptional and immunologic alterations occurring during malignant transformation and identify clinically significant biomarkers of ESCC.

METHODS

Digital spatial profiling (DSP) was performed on 11 patients with early-stage ESCC (pT1) to explore the transcriptional alterations in epithelial, immune cell, and non-immune cell stromal compartments across regions of distinct histology, including normal tissues, low- and high-grade dysplasia, and cancerous tissues. Furthermore, single-cell spatial transcriptomics was performed using the CosMx Spatial Molecular Imaging (SMI) system on 4 additional patients with pT1 ESCC. Immunohistochemical (IHC) analysis was performed on consecutive histological sections of 20 pT1 ESCCs. Additionally, public bulk and single-cell RNA-sequencing (scRNA-seq) datasets were analyzed, and in vitro and in vivo functional studies were conducted.

RESULTS

Spatial transcriptional reprogramming and dynamic cell signaling pathways that determined ESCC progression were delineated. Increased infiltration of macrophages from normal tissues through dysplasia to cancerous tissues occurred. Macrophage subtypes were characterized using the scRNA-seq dataset. Cell-cell communication analysis of scRNA-seq and SMI data indicated that the migration inhibitory factor (MIF)-CD74 axis may exhibit pro-tumor interactions between macrophages and epithelial cells. DSP, SMI, and IHC data demonstrated that DTX3L expression in epithelial cells and BST2 expression in stromal cells increased gradually with ESCC progression. Functional studies demonstrated that DTX3L or BST2 knockdown inhibited ESCC proliferation and migration and decreased M2 polarization of tumor-associated macrophages.

CONCLUSIONS

Spatial profiling comprehensively characterized the molecular and immunological hallmarks from normal tissue to ESCC, guiding the way to a deeper understanding of the tumorigenesis and progression of this disease and contributing to the prevention of ESCC. Within this exploration, we uncovered biomarkers that exhibit a robust correlation with ESCC progression, offering potential new avenues for insightful therapeutic approaches.

Flavokawain C inhibits proliferation and migration of liver cancer cells through FAK/PI3K/AKT signaling pathway

PURPOSE

This study investigated the potential applicability and the underlying mechanisms of flavokawain C, a natural compound derived from kava extracts, in liver cancer treatment.

METHODS

Drug distribution experiment used to demonstrate the preferential tissues enrichment of flavokawain C. Cell proliferation, apoptosis and migration effect of flavokawain C were determined by MTT, colony formation, EdU staining, cell adhesion, transwell, flow cytometry and western blot assay. The mechanism was explored by comet assay, immunofluorescence assay, RNA-seq-based Kyoto encyclopedia of genes and genomes analysis, molecular dynamics, bioinformatics analysis and western blot assay. The anticancer effect of flavokawain C was further confirmed by xenograft tumor model.

RESULTS

The studies first demonstrated the preferential enrichment of flavokawain C within liver tissues in vivo. The findings demonstrated that flavokawain C significantly inhibited proliferation and migration of liver cancer cells, induced cellular apoptosis, and triggered intense DNA damage along with strong DNA damage response. The findings from RNA-seq-based KEGG analysis, molecular dynamics, bioinformatics analysis, and western blot assay mechanistically indicated that treatment with flavokawain C notably suppressed the FAK/PI3K/AKT signaling pathway in liver cancer cells. This effect was attributed to the induction of gene changes and the binding of flavokawain C to the ATP sites of FAK and PI3K, resulting in the inhibition of their phosphorylation. Additionally, flavokawain C also displayed the strong capacity to inhibit Huh-7-derived xenograft tumor growth in mice with minimal adverse effects.

CONCLUSIONS

These findings identified that flavokawain C is a promising anticancer agent for liver cancer treatment.

DTX3L mediated ubiquitination of cGAS suppresses antitumor immunity in pancreatic cancer

The global incidence of pancreatic cancer is associated with a high mortality rate and one of the lowest survival rates among all types of cancer. The clinical management modalities for pancreatic cancer encompass surgical intervention, chemotherapy, radiation therapy, targeted therapy, immunotherapy, or a combination thereof. Nevertheless, the diagnosis of pancreatic cancer often occurs at an advanced stage, thereby restricting treatment options and diminishing the prospects of achieving a cure. The cGAS-STING pathway has emerged as a potential target for antitumor therapy due to its role in promoting immune responses against cancer cells. Activation of the cGAS-STING pathway in tumor cells can lead to the production of pro-inflammatory cytokines and type I interferons, which can enhance the recruitment and activation of immune cells to the tumor microenvironment. The cGAS protein was detected in only a half of tumor tissues in pancreatic cancer patients and the underlying mechanism is still elusive. In this study, we have identified the E3 ligase DTX3L as a key regulator of cGAS-STING signaling in pancreatic cancer cells by mediating the ubiquitination and degradation of cGAS. The expression levels of DTX3L were found to be upregulated in pancreatic tumor tissues and correlated with a poor prognosis for patients with pancreatic cancer. Silencing of DTX3L resulted in enhanced activation of the cGAS-STING signaling pathway and improved antitumor immunity for pancreatic cancer, suggesting that targeting the DTX3L-cGAS axis could hold promise for the treatment of this disease.

New emerging targets in osteosarcoma therapy: PTEN and PI3K/Akt crosstalk in carcinogenesis

Osteosarcoma (OS) is a malignant bone carcinoma that affects people in childhood and adulthood. The heterogeneous nature and chromosomal instability represent certain characteristics of OS cells. These cancer cells grow and migrate abnormally, making the prognosis undesirable for patients. Conventional and current treatments fail to completely eradicate tumor cells, so new therapeutics targeting genes may be considered. PI3K/Akt is a regulator of events such as growth, cell death, migration, and differentiation, and its expression changes during cancer progression. PTEN reduces PI3K/Akt expression, and its mutations and depletions have been reported in various tumors. Experimental evidence shows that there is upregulation of PI3K/Akt and downregulation of PTEN in OS. Increasing PTEN expression may suppress PI3K/Akt to minimize tumorigenesis. In addition, PI3K/Akt shows a positive association with growth, metastasis, EMT and metabolism of OS cells and inhibits apoptosis. Importantly, overexpression of PI3K/Akt causes drug resistance and radio-resistance and its level can be modulated by miRNAs, lncRNAs and circRNAs. Silencing PI3K/Akt by compounds and drugs can suppress OS. Here, we review in detail the function of the PTEN/PI3K/Akt in OS, revealing its biological function, function in tumor progression, resistance to therapy, and pharmacological significance.