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.

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.

Lung cancer is one of the most common malignancies worldwide. Non-small-cell lung cancer (NSCLC) accounts for more than 80% of lung cancers, shows chemotherapy resistance, metastasis, and relapse. The phosphatidylinositol-3 kinase (PI3K)/Akt pathway has been implicated in the carcinogenesis and disease progression of NSCLC, suggesting that it may be a promising therapeutic target for cancer therapy. Although phenylurea derivatives have been reported as potent multiple kinase inhibitors, novel unsymmetrical N,Nʹ-diarylurea derivatives targeting the PI3K/Akt pathway in NSCLC cells remain unknown. Methods: N,Nʹ-substituted phenylurea derivatives CTPPU and CT-(4-OH)-PU were investigated for their anticancer proliferative activity against three NSCLC cell lines (H460, A549, and H292) by 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide, colony formation, Hoechst33342/PI staining assays, and apoptosis analysis. The protein expressions of Akt pathway-related proteins in response to CTPPU or CT-(4-OH)-PU were detected by Western blot analysis. The Kyoto Encyclopedia of Genes and Genomes mapper was used to identify the possible signaling pathways in NSCLC treated with CTPPU. The cell cycle was analyzed by flow cytometry. Molecular docking was used to investigate the possible binding interaction of CTPPU with Akt, the mammalian target of rapamycin complex 2 (mTORC2), and PI3Ks. Immunofluorescence and Western blot analysis were used to validate our prediction. Results: The cytotoxicity of CTPPU was two-fold higher than that of CT-(4-OH)-PU for all NSCLC cell lines. Similarly, the non-cytotoxic concentration of CTPPU (25 µM) dramatically inhibited the colony formation of NSCLC cells, whereas its relative analog CT-(4-OH)-PU had no effect. Protein analysis revealed that Akt and its downstream effectors, namely, phosphorylated glycogen synthase kinase (GSK)-3β (Ser9), β-catenin, and c-Myc, were reduced in response to CTPPU treatment, which suggested the targeting of Akt-dependent pathway, whereas CT-(4-OH)-PU had no effect on such cell growth regulatory signals. CTPPU induced G1/S cell cycle arrest in lung cancer cells. Immunofluorescence revealed that CTPPU decreased p-Akt and total Akt protein levels, which implied the effect of the compound on protein activity and stability. Next, we utilized in silico molecular docking analysis to reveal the potential molecular targets of CTPPU, and the results showed that the compound could specifically bind to the allosteric pocket of Akt and three sites of mTORC2 (catalytic site, A-site, and I-site), with a binding affinity greater than that of reference compounds. The compound cannot bind to PI3K, an upstream regulator of the Akt pathway. The effect of CTPPU on PI3K and Akt was confirmed. This finding indicated that the compound could decrease p-Akt but caused no effect on p-PI3K. Conclusions: The results indicate that CTPPU significantly inhibits NSCLC cell proliferation by inducing G1/S cell cycle arrest via the Akt/GSK-3β/c-Myc signaling pathway. Molecular docking revealed that CTPPU could interact with Akt and mTORC2 molecules with a high binding affinity. These data indicate that CTPPU is a potential novel alternative therapeutic approach for NSCLC.

Cancer stem cells (CSCs) found within cancer tissue play a pivotal role in its resistance to therapy and its potential to metastasize, contributing to elevated mortality rates among patients. Significant strides in understanding the molecular foundations of CSCs have led to preclinical investigations and clinical trials focused on CSC regulator β-catenin signaling targeted interventions in malignancies. As part of the ongoing advancements in marine-organism-derived compound development, it was observed that among the six analogs of Renieramycin T (RT), a potential lead alkaloid from the blue sponge Xestospongia sp., the compound DH_32, displayed the most robust anti-cancer activity in lung cancer A549, H23, and H292 cells. In various lung cancer cell lines, DH_32 exhibited the highest efficacy, with IC₅₀ values of 4.06 ± 0.24 μM, 2.07 ± 0.11 μM, and 1.46 ± 0.06 μM in A549, H23, and H292 cells, respectively. In contrast, parental RT compounds had IC₅₀ values of 5.76 ± 0.23 μM, 2.93 ± 0.07 μM, and 1.52 ± 0.05 μM in the same order. Furthermore, at a dosage of 25 nM, DH_32 showed a stronger ability to inhibit colony formation compared to the lead compound, RT. DH_32 was capable of inducing apoptosis in lung cancer cells, as demonstrated by increased PARP cleavage and reduced levels of the proapoptotic protein Bcl2. Our discovery confirms that DH_32 treatment of lung cancer cells led to a reduced level of CD133, which is associated with the suppression of stem-cell-related transcription factors like OCT4. Moreover, DH_32 significantly suppressed the ability of tumor spheroids to form compared to the original RT compound. Additionally, DH_32 inhibited CSCs by promoting the degradation of β-catenin through ubiquitin–proteasomal pathways. In computational molecular docking, a high-affinity interaction was observed between DH_32 (grid score = −35.559 kcal/mol) and β-catenin, indicating a stronger binding interaction compared to the reference compound R9Q (grid score = −29.044 kcal/mol). In summary, DH_32, a newly developed derivative of the right-half analog of RT, effectively inhibited the initiation of lung cancer spheroids and the self-renewal of lung cancer cells through the upstream process of β-catenin ubiquitin–proteasomal degradation.

New N-containing xanthone analogs of α-mangostin were synthesized via one-pot Smiles rearrangement. Using cesium carbonate in the presence of 2-chloroacetamide and catalytic potassium iodide, α-mangostin (1) was subsequently transformed in three steps to provide ether 2, amide 3, and amine 4 in good yields at an optimum ratio of 1:3:3, respectively. The evaluation of the biological activities of α-mangostin and analogs 2–4 was described. Amine 4 showed promising cytotoxicity against the non-small-cell lung cancer H460 cell line fourfold more potent than that of cisplatin. Both compounds 3 and 4 possessed antitrypanosomal properties against Trypanosoma brucei rhodesiense at a potency threefold stronger than that of α-mangostin. Furthermore, ether 2 gave potent SARS-CoV-2 main protease inhibition by suppressing 3-chymotrypsinlike protease (3CL^pro) activity approximately threefold better than that of 1. Fragment molecular orbital method (FMO–RIMP2/PCM) indicated the improved binding interaction of 2 in the 3CL^pro active site regarding an additional ether moiety. Thus, the series of N-containing α-mangostin analogs prospectively enhance druglike properties based on isosteric replacement and would be further studied as potential biotically active chemical entries, particularly for anti-lung-cancer, antitrypanosomal, and anti-SARS-CoV-2 main protease applications.

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.