Klotho inhibits EGF-induced cell migration in Caki-1 cells through inactivation of EGFR and p38 MAPK signaling pathways

Role of Fibroblast Growth Factor 23 (FGF23) and αKlotho in Cancer

Together with fibroblast growth factors (FGFs) 19 and 21, FGF23 is an endocrine member of the family of FGFs. Mainly secreted by bone cells, FGF23 acts as a hormone on the kidney, stimulating phosphate excretion and suppressing formation of 1,25(OH)₂D₃, active vitamin D. These effects are dependent on transmembrane protein αKlotho, which enhances the binding affinity of FGF23 for FGF receptors (FGFR). Locally produced FGF23 in other tissues including liver or heart exerts further paracrine effects without involvement of αKlotho. Soluble Klotho (sKL) is an endocrine factor that is cleaved off of transmembrane Klotho or generated by alternative splicing and regulates membrane channels, transporters, and intracellular signaling including insulin growth factor 1 (IGF-1) and Wnt pathways, signaling cascades highly relevant for tumor progression. In mice, lack of FGF23 or αKlotho results in derangement of phosphate metabolism and a syndrome of rapid aging with abnormalities affecting most organs and a very short life span. Conversely, overexpression of anti-aging factor αKlotho results in a profound elongation of life span. Accumulating evidence suggests a major role of αKlotho as a tumor suppressor, at least in part by inhibiting IGF-1 and Wnt/β-catenin signaling. Hence, in many malignancies, higher αKlotho expression or activity is associated with a more favorable outcome. Moreover, also FGF23 and phosphate have been revealed to be factors relevant in cancer. FGF23 is particularly significant for those forms of cancer primarily affecting bone (e.g., multiple myeloma) or characterized by bone metastasis. This review summarizes the current knowledge of the significance of FGF23 and αKlotho for tumor cell signaling, biology, and clinically relevant parameters in different forms of cancer.

SCAMP3 is regulated by miR-128-3p and promotes the metastasis of hepatocellular carcinoma cells through EGFR-MAPK p38 signaling pathway

PURPOSE

To explore the regulatory mechanism of secretory carrier membrane protein 3 (SCAMP3) and miR-128-3p in hepatocellular carcinoma (HCC).

PATIENTS AND METHODS

Cancer tissues and adjacent tissues of 52 HCC patients treated in our hospital were collected to explore the prognostic factors affecting their 3-year survival. HCC cells were purchased, the gene expression of Huh-7 and MHCC97 were adjusted by transfection, and the levels of SCAMP3, miR-128-3p, EGFR, p-EGFR, MAPK p38, p-MAPK p38, N-cadherin, vimentin, E-cadherin, cell proliferation, migration, invasion, apoptosis and epithelial-mesenchymal transition (EMT) were detected. A nude mouse model of HCC was constructed to verify the effects of transfection of mimics.

RESULTS

SCAMP3 was elevated in HCC patients and cancer tissues of HCC patients, while miR-128-3p showed opposite effects. High level SCAMP3 and low level miR-128-3p were related to poor prognosis of HCC. Both of them were correlated with excessive drinking history, N-stage, M-stage and pathological differentiation degree of HCC patients, as well as prognostic factors of HCC patients. SCAMP3 up-regulation or miR-128-3p down-regulation could promote HCC cell proliferation, migration, invasion, and transcription and protein levels of EGFR, p-EGFR, MAPK p38, p-MAPK p38, N-cadherin and vimentin, and inhibit HCC cell apoptosis and transcription and protein levels of E-cadherin. Dual luciferase reporter identified the targeting relationship between SCAMP3 and miR-128-3p. When both SCAMP3 and miR-128-3p were elevated or reduced, the biological manifestation of cells was not different from that of miR-NC transfected with unrelated sequences. Besides, miR-128-3p inhibited tumor growth in the HCC model in nude mice.

CONCLUSION

SCAMP3 can be controlled by miR-128-3p and can mediate the EGFR-MAPK p38 signaling pathway to inhibit HCC cell metastasis, which is expected to become a promising therapeutic target for HCC.

Identification of low-dose multidrug combinations for sunitinib-naive and pre-treated renal cell carcinoma

Background

Combinations of drugs can improve the efficacy of cancer treatment, enable the reduction of side effects and the occurrence of acquired drug resistance.

Methods

We approached this challenge mathematically by using the validated technology called the Therapeutically Guided Multidrug Optimization (TGMO) method. In a set of genetically distinct human renal cell carcinoma (RCC) cell lines, either treated chronically with sunitinib (−ST) or sunitinib-naive, we identified cell line-specific low-dose-optimised drug combinations (ODC).

Results

Six cell-type-specific low-dose drug combinations for three sunitinib-naive as well as three sunitinib pre-treated cells were established. These ODCs effectively inhibited the RCC cell metabolic activity while being ineffective in non-cancerous cells. Based on a single screening test and three searches, starting with ten drugs, we identified highly efficacious drug mixtures containing four drugs. All ODCs contained AZD4547 (FGFR signalling pathway inhibitor) and pictilisib (pan-phosphatidylinositol 3-kinase inhibitor), but varied in the third and fourth drug. ODC treatment significantly decreased cell metabolic activity (up to 70%) and induced apoptosis, independent of the pretreatment with sunitinib. The ODCs outperformed sunitinib, the standard care for RCC. Moreover, short-term starvation potentiated the ODC activity. The translation of the 2D-based results to 3D heterotypic co-culture models revealed significant inhibition of the spheroid growth (up to 95%).

Conclusion

We demonstrate a promising low-dose drug combination development to obtain drug combinations effective in naive as well as resistant tumours. Nevertheless, we emphasise the need for further mechanistic investigation and preclinical development.

VHL-HIF-2α axis-induced SMYD3 upregulation drives renal cell carcinoma progression via direct trans-activation of EGFR

It has been well established that the von Hippel-Lindau/hypoxia-inducible factor α (VHL-HIFα) axis and epidermal growth factor receptor (EGFR) signaling pathway play a critical role in the pathogenesis and progression of renal cell carcinoma (RCC). However, few studies have addressed the relationship between the two oncogenic drivers in RCC. SET and MYND domain-containing protein 3 (SMYD3) is a histone methyltransferase involved in gene transcription and oncogenesis, but its expression and function in RCC remain unclear. In the present study, we found that SMYD3 expression was significantly elevated in RCC tumors and correlated with advanced tumor stage, histological and nuclear grade, and shorter survival. Depletion of SMYD3 inhibited RCC cell proliferation, colony numbers, and xenograft tumor formation, while promoted apoptosis. Mechanistically, SMYD3 cooperates with SP1 to transcriptionally promote EGFR expression, amplifying its downstream signaling activity. TCGA data analyses revealed a significantly increased SMYD3 expression in primary RCC tumors carrying the loss-of-function VHL mutations. We further showed that HIF-2α can directly bind to the SMYD3 promoter and subsequently induced SMYD3 transcription and expression. Taken together, we identify the VHL/HIF-2α/SMYD3 signaling cascade-mediated EGFR hyperactivity through which SMYD3 promotes RCC progression. Our study suggests that SMYD3 is a potential therapeutic target and prognostic factor in RCC.

IGFBP2 regulates PD-L1 expression by activating the EGFR-STAT3 signaling pathway in malignant melanoma

Immunotherapy targeting the PD-1/PD-L1 receptor has achieved great success in melanoma patients. Although many studies have addressed the underlying mechanisms involved in the blockade of PD-1/PD-L1 and the consequent modulation of the immune system, the mechanisms of PD-L1 upregulation and reliable biomarkers to predict the efficacy of anti-PD-1/PD-L1 therapy remain unknown. The present study demonstrates the correlation between IGFBP2 and PD-L1, revealing a novel immune-associated tumor function of IGFBP2 in facilitating nuclear accumulation of EGFR and activation of the EGFR/STAT3/PD-L1 signaling pathway in melanoma cells. Our results also suggest that combined IGFBP2 and PD-L1 expression has the potential to predict the efficacy of anti-PD-1 treatment for malignant melanoma; because the combination of high IGFBP2 and PD-L1 expression characterizes melanoma patients with worse overall survival and is associated with a better immune ecosystem. These characteristics have been confirmed by both in vitro and in vivo data. Consequently, IGFBP2 regulates PD-L1 expression by activating the EGFR-STAT3 signaling pathway and its function as a PD-L1 regulator might suggest novel therapeutic approach for melanoma.

Towards Age-Related Anti-Inflammatory Therapy: Klotho Suppresses Activation of ER and Golgi Stress Response in Senescent Monocytes

Immunosenescence in monocytes has been shown to be associated with several biochemical and functional changes, including development of senescence-associated secretory phenotype (SASP), which may be inhibited by klotho protein. To date, it was believed that SASP activation is associated with accumulating DNA damage. However, some literature data suggest that endoplasmic reticulum and Golgi stress pathways may be involved in SASP development. Thus, the aim of this study was to investigate the role of klotho protein in the regulation of immunosenescence-associated Golgi apparatus and ER stress response induced by bacterial antigens in monocytes. We provide evidence that initiation of immunosenescent-like phenotype in monocytes is accompanied by activation of CREB34L and TFE3 Golgi stress response and ATF6 and IRE1 endoplasmic reticulum stress response, while klotho overexpression prevents these changes. Further, these changes are followed by upregulated secretion of proinflammatory cytokines, which final modification takes place exclusively in the Golgi apparatus. In conclusion, we provide for the first time evidence of klotho involvement in the crosstalk on the line ER-Golgi, which may, in turn, affect activation of SASP. This data may be useful for a novel potential target for therapy in age-related and chronic inflammatory conditions.

Heat injured stromal cells-derived exosomal EGFR enhances prostatic wound healing after thulium laser resection through EMT and NF-κB signaling

BACKGROUND

This study investigated shallow heat injury to prostate stromal fibroblasts and epithelial cells and their interaction to regulate the wound healing and the underlying molecular events.

METHODS

Prostate stromal fibroblasts and epithelial cells were cultured individually or cocultured and subjected to shallow heat injury for assessments of cell proliferation, migration, apoptosis, cell cycle distribution, and gene expression. The supernatant of heat-injured WPMY-1 cells was collected for exosome extraction and assessments. Furthermore, beagle dogs received thulium laser resection of the prostate (TmLRP) and randomly divided into Gefitinib, GW4869, and control treatment for the histological analysis, tissue re-epithelialization, and epidermal growth factor receptor (EGFR) expression on the prostatic wound surface. Immunofluorescence was to evaluate p63-positive basal progenitor cell trans-differentiation and macrophage polarization and ELISA was to detect cytokine levels in beagles' urine.

RESULTS

Shallow heat injury caused these cells to enter a stressed state and enhanced their crosstalk. The prostate stromal fibroblasts produced and secreted more exosomal-EGFR and other cytokines and chemokines after shallow heat injury, resulting in increased proliferation and migration of prostate epithelial cells during wound healing. The wound healing of the canine prostatic urethra following the TmLRP procedure was slower in the Gefitinib and GW4869 treatment group than in the control group of animals. Immunofluorescence and ELISA showed that reduced EGFR expression interrupted macrophage polarization but increased the inflammatory response.

CONCLUSIONS

Shallow heat injury was able to promote the interaction of prostate stromal cells with prostate epithelial cells to enhance wound healing. Stromal-derived exosomal-EGFR plays a crucial role in the balance of the macrophage polarization and prostatic wound healing.