FHL1 promotes glioblastoma aggressiveness through regulating EGFR expression

EphB3 receptor suppressor invasion, migration and proliferation in glioma by inhibiting EGFR-PI3K/AKT signaling pathway

Eph receptors are the largest subfamily of receptor tyrosine kinases, and they have been shown to play a crucial role in glioma. The EphB3 receptor is a member of this family, and its effect on the invasion, migration and proliferation of glioma cells was examined in this study. It was found that the expression of EphB3 was decreased in glioma specimens with increasing tumor grade. Additionally, the U87MG and U251 cell lines showed low levels of EphB3 expression. This finding was consistent with the negative correlation between EphB3 expression in glioma tissues and tumor grade. Depletion of EphB3 gene in U87MG and U251 cell lines resulted in a substantial enhancement of their invasion, migration, and proliferation capacities in vitro. Furthermore, the knockdown of EphB3 led to an upregulation of EGFR, p-PI3K, and p-AKT protein levels. On the other hand, EphB3 overexpression reduced the invasiveness, proliferative capacity and migration rate of U87MG and U251 cells, and downregulated EGFR, p-PI3K and p-AKT. These findings indicate that EphB3 functions as a tumor suppressor in glioma, and its downregulation enhances the malignant potential of glioma cells by activating the EGFR-PI3K/AKT pathway. Thus, EphB3 is a promising diagnostic marker for glioma, and the EphB3-EGFR-PI3K / AKT axis deserves further investigation as a potential therapeutic target.

Oncolytic herpes simplex viruses designed for targeted treatment of EGFR-bearing tumors

Oncolytic herpes simplex viruses (oHSVs) have emerged as leading cancer therapeutic agents. Effective oHSV virotherapy may ultimately require both intratumoral and systemic vector administration to target the primary tumor and distant metastases. An attractive approach to enhancing oHSV tumor specificity is engineering the virus envelope glycoproteins for selective recognition of and infection via tumor-specific cell surface proteins. We previously demonstrated that oHSVs could be retargeted to EGFR-expressing cells by the incorporation of a single-chain antibody (scFv) at the N terminus of glycoprotein D (gD). Here, we compared retargeted oHSVs generated by the insertion of scFv, affibody molecule, or VHH antibody ligands at different positions within the N terminus of gD. When compared to the scFv-directed oHSVs, VHH and affibody molecules mediated enhanced EGFR-specific tumor cell entry, spread and cell killing in vitro, and enabled long-term tumor-specific virus replication following intravenous delivery in vivo. Moreover, oHSVs retargeted via a VHH ligand reduced tumor growth upon intravenous injection and achieved complete tumor destruction after intratumoral injection. Systemic oHSV delivery is important for the treatment of metastatic disease, and our enhancements in targeted oHSV design are a critical step in creating an effective tumor-specific oHSVs for safe administration via the bloodstream.

Targeting FHL1 impairs cell proliferation and differentiation of acute myeloid leukemia cells

The four and a half LIM domains 1 (FHL1) is considered to play important roles in tumors. This study aims to investigate the role and precise mechanisms of FHL1 in acute myeloid leukemia (AML). Here, we found that FHL1 was highly expressed in AML. CCK8, flow cytometry, and Western blot analysis of cell cycle-related proteins showed that overexpression of FHL1 promoted proliferation and accelerated cell cycle progression in HL-60 cells. Conversely, knockdown of FHL1 inhibited the proliferation and induced cell cycle arrest in KG-1 cells. Furthermore, knockdown of FHL1 promoted cell differentiation, while overexpression of FHL1 restrained all-trans retinoic acid induced cell differentiation in HL-60 cells, revealed by Wright-Giemsa staining and cell surface antigen analysis. Moreover, in vivo experiments revealed that depletion of FHL1 inhibited tumor growth and led to increased levels of CD11b and CD14. Here, we first identify an unexpected and important role of FHL1 that contributes to the AML progression, indicating that FHL1 may be a potential therapeutic target for AML.