Downregulation of PLK4 expression induces apoptosis and G0/G1-phase cell cycle arrest in keloid fibroblasts

FoxC1 activates Notch3 signaling to promote the inflammatory phenotype of keloid fibroblasts and aggravates keloid

Keloids are disfiguring proliferative scars, and their pathological mechanisms are still unclear. We have previously established that FoxC1 plays a significant role in rheumatoid arthritis and osteoarthritis, but its molecular mechanisms in pathological scar formation remain elusive. In this study, we analyzed keloid tissue characteristics using HE staining and immunohistochemistry, revealing abnormal expression of FoxC1 and Notch3 in keloids. Lentiviral modulation of FoxC1 and Notch3 demonstrated that they promote the expression of α-SMA, fibronectin, collagen I, and Hes-1, enhancing the proliferation, migration, invasion, and cytokine production of keloid fibroblasts (KFs) while inhibiting apoptosis. Co-immunoprecipitation (CO-IP), dual-luciferase reporter assays, and chromatin immunoprecipitation (ChIP) confirmed that FoxC1 can directly bind to the Notch3 promoter and enhance its transcription. Additionally, in vivo, overexpression of FoxC1 and Notch3 promoted keloid formation. In summary, our research highlights the critical regulatory role of FoxC1 in keloid formation through Notch3 activation, potentially offering new therapeutic targets for preventing scar formation.

NL13, a novel curcumin analogue and polo like kinase 4 inhibitor, induces cell cycle arrest and apoptosis in prostate cancer models

BACKGROUND AND PURPOSE

Prostate cancer remains a major public health burden worldwide. Polo like kinase 4 (PLK4) has emerged as a promising therapeutic target in prostate cancer due to its key roles in cell cycle regulation and tumour progression. This study aims to develop and characterize the novel curcumin analogue NL13 as a potential therapeutic agent and PLK4 inhibitor against prostate cancer.

EXPERIMENTAL APPROACH

NL13 was synthesized and its effects were evaluated in prostate cancer cells and mouse xenograft models. Kinome screening and molecular modelling identified PLK4 as the primary target. Antiproliferative and proapoptotic mechanisms were explored via cell cycle, apoptosis, gene and protein analyses.

KEY RESULTS

Compared with curcumin, NL13 exhibited much greater potency in inhibiting PC3 (IC50, 3.51 μM vs. 35.45 μM) and DU145 (IC50, 2.53 μM vs. 29.35 μM) prostate cancer cells viability and PLK4 kinase activity (2.32 μM vs. 246.88 μM). NL13 induced G2/M cell cycle arrest through CCNB1/CDK1 down-regulation and triggered apoptosis via caspase-9/caspase-3 cleavage. These effects were mediated by PLK4 inhibition, which led to the inactivation of the AKT signalling pathway. In mice, NL13 significantly inhibited tumour growth and modulated molecular markers consistent with in vitro findings, including decreased p-AKT and increased cleaved caspase-9/3.

CONCLUSION AND IMPLICATIONS

NL13, a novel PLK4-targeted curcumin analogue, exerts promising anticancer properties against prostate cancer by disrupting the PLK4-AKT-CCNB1/CDK1 and apoptosis pathways. NL13 represents a promising new agent for prostate cancer therapy.

Placental mesenchymal stem cells-secreted proenkephalin suppresses the p38 MAPK signaling to block hyperproliferation of keloid fibroblasts

BACKGROUND

Thanks to their multi-potency and secretory functions, mesenchymal stem cells (MSCs) have long been established as an ideal cell type for skin wound healing and a candidate therapeutic strategy for excessive pathological scarring in the meantime. This study focuses on the effect of placental MSCs (PMSCs) on the activity of keloid fibroblasts (KFs) and the potential involvement of proenkephalin (PENK).

METHODS

Secretory protein of PMSC that are lowly expressed in KFs were predicted by bioinformatics analyses. The expression of PENK in KFs was detected by RT-qPCR and western blot analysis. PMSCs were co-cultured with KFs and dermal fibroblasts (DFs) to examine their effect on proliferation, migration, invasion, and apoptosis of the distinct cell types. PENK secretion by PMSCs and its uptake by KFs were examined by ELISA, WB, and immunofluorescence staining. Loss-of-functions of PENK and p38-MAPK were induced to examine the activity of KFs in vitro and in mice.

RESULTS

PENK, a secretory protein of PMSCs, was conspicuously downregulated in KFs compared to normal DFs. PMSC stimulation suppressed proliferation, migration, invasion, and resistance to apoptosis of the co-cultured KFs but not DFs, which was ascribed to the upregulation of PENK protein in KFs. PMSCs-secreted PENK suppressed p38 phosphorylation in KFs. The proliferative and aggressive properties of KFs in vitro and the nodule-forming capacity of KFs in vivo were promoted upon PENK downregulation but suppressed by the p38 MAPK inhibitor SB202190.

CONCLUSION

This work unravels that PMSCs-secreted PENK suppresses the p38 MAPK signaling to block hyperproliferation of KFs.

Polo-like Kinase 4: A Multifaceted Marker Linking Tumor Aggressiveness and Unfavorable Prognosis, and Insights into Therapeutic Strategies

(1) Background: This study investigated whether polo-like kinase 4 (PLK4) is a suitable therapeutic target or biomarker for lung adenocarcinoma (LUAD). (2) Methods: We acquired LUAD data from The Cancer Genome Atlas (TCGA) database through the UCSC Xena data portal. Gene expression, clinical, survival, and mutation data from multiple samples were analyzed. Gene enrichment analysis, unsupervised clustering of PLK4-related pathways, and differential gene expression analyses were performed. Additionally, correlations, t-tests, survival analyses, and statistical analyses were performed. (3) Results: PLK4 expression was higher in LUAD tissues than in normal tissues and was associated with poor prognosis for both overall and progression-free survival in LUAD. PLK4 was highly correlated with cell-proliferation-related pathways using Gene Ontology (GO) biological process terms. PLK4 expression and pathways that were highly correlated with PLK4 expression levels were upregulated in patients with LUAD with the TP53 mutation. (4) Conclusions: PLK4 expression affects the survival of patients with LUAD and is a potential therapeutic target for LUAD with TP53 mutations.

TWEAK/Fn14 signaling may function as a reactive compensatory mechanism against extracellular matrix accumulation in keloid fibroblasts

Overabundance of the extracellular matrix resulting from hyperproliferation of keloid fibroblasts (KFs) and dysregulation of apoptosis represents the main pathophysiology underlying keloids. TWEAK is a weak apoptosis inducer, and it plays a critical role in pathological tissue remodeling via its receptor, Fn14. However, the role of TWEAK/Fn14 signaling in the pathogenesis of keloids has not been investigated. In this study, we confirmed the overexpression levels of TWEAK and Fn14 in clinical keloid tissue specimens and primary KFs. The extracellular matrix (ECM)-related genes were also evaluated between primary KFs and their normal counterparts to determine the factors leading to the formation or development of keloids. Unexpectedly, exogenous TWEAK significantly reduced the levels of collagen I and collagen III, as well as alpha-smooth muscle actin (α-SMA). Additionally, TWEAK promoted MMPs expression and apoptosis activity of KFs. Furthermore, we verified that the inhibitory effect of TWEAK on KFs is through down-regulation of Polo-like kinase 5, which modulates cell differentiation and apoptosis. The TWEAK-Fn14 axis seems to be a secondary, although less effective, compensatory mechanism to increase the catabolic functions of fibroblasts in an attempt to further decrease the accumulation of collagen. DATA AVAILABILITY: All data generated or analyzed during this study are included in this published article (and its Supporting Information files).