Cisplatin (CDDP) induces senescence characterized by senescence-associated secretory phenotypes (SASP) and the unfolded protein response (UPR). In this study, we investigated the proteins related to the UPR during the senescence cell fate. Strikingly, we found that one of the critical ER-resident proteins, GRP78/BiP, was significantly altered. Here we show that GRP78 levels differentially expressed depending on non-small lung cancer subtypes. GRP78 indeed regulates the evasion of senescence in adenocarcinoma A549 cells, in which the increased GRP78 levels enable them to re-proliferate after CDDP removal. Conversely, GRP78 is downregulated in the senescence H460 cells, making them lacking senescence evasion capability. We observed that the translational regulation critically contributed to the GRP78 protein levels in CDDP-induces senescence. Furthermore, the increased GRP78 level during senescence confers resistance to senolytic drug, Bortezomib, as observed by a twofold increase in IC50 in A549 senescence cells compared to the wild-type. This observation is also consistent in the cells that have undergone genetic manipulation by transfection with pcDNA3.1(+)-GRP78/BiP plasmids and pSpCas9(BB)-2A-Puro containing guide RNA sequence targeting GRP78 exon 3 to induce the overexpression and downregulation of GRP78 in H460 cells, respectively. Our findings reveal a unique role of GRP78 on the senescence evasion cell fate and senolytic drug resistance after cisplatin-based chemotherapy.
Stem cells have demonstrated significant potential for tissue engineering and repair, anti-aging, and rejuvenation. Hair follicle stem cells can be found in the dermal papilla at the base of the follicle and the bulge region, and they have garnered increased attention because of their potential to regenerate hair as well as their application for tissue repair. In recent years, these cells have been shown to affect hair restoration and prevent hair loss. These stem cells are endowed with mesenchymal characteristics and exhibit self-renewal and can differentiate into diverse cell types. As research in this field continues, it is probable that insights regarding stem cell maintenance, as well as their self-renewal and differentiation abilities, will benefit the application of these cells. In addition, an in-depth discussion is required regarding the molecular basis of cellular signaling and the influence of nature-derived compounds in stimulating the stemness properties of dermal papilla stem cells. This review summarizes (i) the potential of the mesenchymal cells component of the hair follicle as a target for drug action; (ii) the molecular mechanism of dermal papilla stem cells for maintenance of their stem cell function; and (iii) the positive effects of the natural product compounds in stimulating stemness in dermal papilla stem cells. Together, these insights may help facilitate the development of novel effective hair loss prevention and treatment.
Akt is a key regulatory protein of cancer stem cells (CSCs) and is responsible for cancer aggressiveness and metastasis. Targeting Akt is beneficial for the development of cancer drugs. renieramycin T (RT) has been reported to have Mcl-1 targeting activity, and the study of the structure-activity relationships (SARs) demonstrated that cyanide and the benzene ring are essential for its effects. In this study, novel derivatives of the RT right-half analog with cyanide and the modified ring were synthesized to further investigate the SARs for improving the anticancer effects of RT analogs and evaluate CSC-suppressing activity through Akt inhibition. Among the five derivatives, a compound with a substituted thiazole structure (DH_25) exerts the most potent anticancer activity in lung cancer cells. It has the ability to induce apoptosis, which is accompanied by an increase in PARP cleavage, a decrease in Bcl-2, and a diminishment of Mcl-1, suggesting that residual Mcl-1 inhibitory effects exist even after modifying the benzene ring to thiazole. Furthermore, DH_25 is found to induce CSC death, as well as a decrease in CSC marker CD133, CSC transcription factor Nanog, and CSC-related oncoprotein c-Myc. Notably, an upstream member of these proteins, Akt and p-Akt, are also downregulated, indicating that Akt can be a potential target of action. Computational molecular docking showing a high-affinity interaction between DH_25 and an Akt at the allosteric binding site supports that DH_25 can bind and inhibit Akt. This study has revealed a novel SAR and CSC inhibitory effect of DH_25 via Akt inhibition, which may encourage further development of RT compounds for cancer therapy.
Context Endoplasmic reticulum (ER) stress contributes to endothelium pathological conditions. Chitooligosaccharides (COS) have health benefits, but their effect on endothelial cells is unknown. We demonstrate for the first time a protective effect of COS against ER-induced endothelial cell damage. Objective To evaluate the protective effect of COS on ER stress-induced apoptosis in endothelial cells. Material and methods Endothelial (EA.hy926) cells were pre-treated with COS (250 or 500 μg/mL) for 24 h, and then treated with 0.16 μg/mL of Tg for 24 h and compared to the untreated control. Apoptosis and necrosis were detected by Annexin V-FITC/propidium iodide co-staining. Reactive oxygen species (ROS) were measured with the DCFH 2 -DA and DHE probes. The protective pathway and ER stress markers were evaluated by reverse transcription-polymerase chain reaction, western blot, and immunofluorescence analyses. Results COS attenuated ER stress-induced cell death. The viability of EA.hy926 cells treated with Tg alone was 44.97 ± 1% but the COS pre-treatment increased cells viability to 74.74 ± 3.95% in the 250 μg/mL COS and 75.34 ± 2.4% in the 500 μg/mL COS treatments. Tg induced ER stress and ROS, which were associated with ER stress-mediated death. Interestingly, COS reduced ROS by upregulating nuclear factor-E2-related factor 2 (Nrf2), and the oxidative enzymes, superoxide dismutase1 (SOD1) and catalase. COS also suppressed up-regulation of the ER-related apoptosis protein, CHOP induced by Tg. Conclusions COS protected against ER stress-induced apoptosis in endothelial cells by suppressing ROS and up-regulation Nrf2 and SOD1. These findings support the use of COS to protect endothelial cells.
Cellular senescence is linked with chemotherapy resistance. Based on previous studies, GRP78 is a signal transducer in senescent cells. However, the association between GRP78 and stem cell phenotype remains unknown. Cisplatin treatment was clarified to induce cellular senescence leading to stemness induction via GRP78/Akt signal transduction. H460 cells were treated with 5 μM of cisplatin for 6 days to develop senescence. The colony formation assay and cell cycle analysis were performed. SA-β-galactosidase staining indicated senescence. Western blot analysis and RT-PCR were operated. Immunoprecipitation (IP) and immunocytochemistry assays (ICC) were also performed. Colony-forming activity was completely inhibited, and 87.07% of the cell population was arrested in the G2 phase of the cell cycle. mRNA of p21 and p53 increased approximately by 15.91- and 19.32-fold, respectively. The protein level of p21 and p53 was elevated by 9.57- and 5.9-fold, respectively. In addition, the c-Myc protein level was decreased by 0.2-fold when compared with the non-treatment control. Even though, the total of GRP78 protein was downregulated after cisplatin treatment, but the MTJ1 and downstream regulator, p-Akt/Akt ratio were upregulated by approximately 3.38 and 1.44-fold, respectively. GRP78 and MTJ1 were found at the cell surface membrane. Results showed that the GRP78/MTJ1 complex and stemness markers, including CD44, CD133, Nanog, Oct4, and Sox2, were concomitantly increased in senescent cells. MTJ1 anchored GRP78, facilitating the signal transduction of stem-like phenotypes. The strategy that could interrupt the binding between these crucial proteins or inhibit the translocation of GRP78 might beuseful for cancer therapy.
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