Autophagy induction of reversine on human follicular thyroid cancer cells

Reversine inhibits proliferation and induces apoptosis of human osteosarcoma cells through targeting MEK1

Reversine, or 2-(4-morpholinoanilino)-6-cyclohexylaminopurine, is a 2,6-disubstituted purine derivative. This small molecule shows anti-tumor potential by playing a central role in the inhibition of several kinases related to cell cycle regulation and cytokinesis. In this study, systematic review demonstrated the feasibility and pharmacological mechanism of anti-tumor effect of reversine. Firstly, we grafted MNNG/HOS, U-2 OS, MG-63 osteosarcoma cell aggregates onto chicken embryonic chorioallantoic membrane (CAM) to examine the tumor volume of these grafts after reversine treatment. Following culture, reversine inhibited the growth of osteosarcoma cell aggregates on CAM significantly. In vitro experiment, reversine suppressed osteosarcoma cell viability, colony formation, proliferation, and induced apoptosis and cell cycle arrest at G0-G1 phase. Scratch wound assay demonstrated that reversine restrained cell migration. Reversine increased the protein expression of E-cadherin. The mRNA expression of Rac1, RhoA, CDC42, PTK2, PXN, N-cadherin, Vimentin in MNNG/HOS, U-2 OS and MG-63 cells were suppressed and PTEN increased after reversine treatment. Network pharmacology prediction, molecular docking and systematic review revealed MEK1 can be used as an effective target for reversine to inhibit osteosarcoma. Western blot results show the regulation of MEK1 and ERK1/2 by reversine was not consistent in different osteosarcoma cell lines, but we found that reversine significantly inhibited the protein expression of MEK1 in MNNG/HOS, U-2 OS and MG-63. All these suggested that reversine can exert its anti-tumor effect by targeting the expression of MEK1.

In Vitro Characterization of Reversine-Treated Gingival Fibroblasts and Their Safety Evaluation after In Vivo Transplantation

Reversine is a purine derivative that has been investigated with regard to its biological effects, such as its anticancer properties and, mostly, its ability to induce the dedifferentiation of adult cells, increasing their plasticity. The obtained dedifferentiated cells have a high potential for use in regenerative procedures, such as regenerative dentistry (RD). Instead of replacing the lost or damaged oral tissues with synthetic materials, RD uses stem cells combined with matrices and an appropriate microenvironment to achieve tissue regeneration. However, the currently available stem cell sources present limitations, thus restricting the potential of RD. Based on this problem, new sources of stem cells are fundamental. This work aims to characterize mouse gingival fibroblasts (GFs) after dedifferentiation with reversine. Different administration protocols were tested, and the cells obtained were evaluated regarding their cell metabolism, protein and DNA contents, cell cycle changes, morphology, cell death, genotoxicity, and acquisition of stem cell characteristics. Additionally, their teratoma potential was evaluated after in vivo transplantation. Reversine caused toxicity at higher concentrations, with decreased cell metabolic activity and protein content. The cells obtained displayed polyploidy, a cycle arrest in the G2/M phase, and showed an enlarged size. Additionally, apoptosis and genotoxicity were found at higher reversine concentrations. A subpopulation of the GFs possessed stem properties, as supported by the increased expression of CD90, CD105, and TERT, the existence of a CD106+ population, and their trilineage differentiation capacity. The dedifferentiated cells did not induce teratoma formation. The extensive characterization performed shows that significant functional, morphological, and genetic changes occur during the dedifferentiation process. The dedifferentiated cells have some stem-like characteristics, which are of interest for RD.

The new insights into autophagy in thyroid cancer progression

In recent decades, the incidence of thyroid cancer keeps growing at a shocking rate, which has aroused increasing concerns worldwide. Autophagy is a fundamental and ubiquitous biological event conserved in mammals including humans. Basically, autophagy is a catabolic process that cellular components including small molecules and damaged organelles are degraded for recycle to meet the energy needs, especially under the extreme conditions. The dysregulated autophagy has indicated to be involved in thyroid cancer progression. The enhancement of autophagy can lead to autophagic cell death during the degradation while the produced energies can be utilized by the rest of the cancerous tissue, thus this influence could be bidirectional, which plays either a tumor-suppressive or oncogenic role. Accordingly, autophagy can be suppressed by therapeutic agents and is thus regarded as a drug target for thyroid cancer treatments. In the present review, a brief description of autophagy and roles of autophagy in tumor context are given. We have addressed summary of the mechanisms and functions of autophagy in thyroid cancer. Some potential autophagy-targeted treatments are also summarized. The aim of the review is linking autophagy to thyroid cancer, so as to develop novel approaches to better control cancer progression.

Piperlongumine Induces Cellular Apoptosis and Autophagy via the ROS/Akt Signaling Pathway in Human Follicular Thyroid Cancer Cells

Thyroid cancer (TC) is the most common endocrine malignancy. Recently, the global incidence of TC has increased rapidly. Differentiated thyroid cancer includes papillary thyroid carcinoma (PTC) and follicular thyroid carcinoma (FTC), which are the most common types of TC. Although PTCs and FTCs exert good prognoses and high survival rates, FTCs tend to be more aggressive than PTCs. There is an urgent need to improve patient outcomes by developing effective therapeutic agents for FTCs. Piperlongumine exerts anti-cancer effects in various human carcinomas, including human anaplastic TCs and PTCs. However, the anti-cancer effects of piperlongumine in FTCs and the underlying mechanisms are yet to be elucidated. Therefore, in the present study, we evaluated the effect of piperlongumine on cell proliferation, cell cycle, apoptosis, and autophagy in FTC cells with flowcytometry and Western blot. We observed that piperlongumine caused growth inhibition, cell cycle arrest, apoptosis induction, and autophagy elevation in FTC cells. Activities of reactive oxygen species and the downstream PI3K/Akt pathway were the underlying mechanisms involved in piperlongumine mediated anti-FTC effects. Advancements in our understanding of the effects of piperlongumine in FTC hold promise for the development of novel therapeutic strategies.

Reversine ameliorates hallmarks of cellular senescence in human skeletal myoblasts via reactivation of autophagy

Cellular senescence leads to the depletion of myogenic progenitors and decreased regenerative capacity. We show that the small molecule 2,6-disubstituted purine, reversine, can improve some well-known hallmarks of cellular aging in senescent myoblast cells. Reversine reactivated autophagy and insulin signaling pathway via upregulation of Adenosine Monophosphate-activated protein kinase (AMPK) and Akt2, restoring insulin sensitivity and glucose uptake in senescent cells. Reversine also restored the loss of connectivity of glycolysis to the TCA cycle, thus restoring dysfunctional mitochondria and the impaired myogenic differentiation potential of senescent myoblasts. Altogether, our data suggest that cellular senescence can be reversed by treatment with a single small molecule without employing genetic reprogramming technologies.

Identification of Prognostic Biomarkers in Papillary Thyroid Cancer and Developing Non-Invasive Diagnostic Models Through Integrated Bioinformatics Analysis

BACKGROUND

Papillary thyroid cancer (PTC) is the most frequent subtype of thyroid carcinoma, mainly detected in patients with benign thyroid nodules (BTN). Due to the invasiveness of accurate diagnostic tests, there is a need to discover applicable biomarkers for PTC. So, in this study, we aimed to identify the genes associated with prognosis in PTC. Besides, we performed a machine learning tool to develop a non-invasive diagnostic approach for PTC.

METHODS

For the study purposes, the miRNA dataset GSE130512 was downloaded from the GEO database and then analyzed to identify the common differentially expressed miRNAs in patients with non-metastatic PTC (nm-PTC)/metastatic PTC (m-PTC) compared with BTNs. The SVM was also applied to differentiate patients with PTC from those patients with BTN using the common DEMs. A protein-protein interaction network was also constructed based on the targets of the common DEMs. Next, functional analysis was performed, the hub genes were determined, and survival analysis was then executed.

RESULTS

A total of three common miRNAs were found to be differentially expressed among patients with nm-PTC/m-PTC compared with BTNs. In addition, it was established that the autophagosome maturation, ciliary basal body-plasma membrane docking, antigen processing as ubiquitination & proteasome degradation, and class I MHC mediated antigen processing & presentation are associated with the pathogenesis of PTC. Furthermore, it was illustrated that RPS6KB1, CCNT1, SP1, and CHD4 might serve as new potential biomarkers for PTC prognosis.

CONCLUSION

RPS6KB1, CCNT1, SP1, and CHD4 may be considered new potential biomarkers used for prognostic aims in PTC. However, performing validation tests is inevitable in the future.

Piperlongumine, a Potent Anticancer Phytotherapeutic, Induces Cell Cycle Arrest and Apoptosis In Vitro and In Vivo through the ROS/Akt Pathway in Human Thyroid Cancer Cells

Simple Summary

There is no effective treatment currently available for patients with anaplastic, recurrent papillary, or follicular thyroid cancers. Reactive oxygen species (ROS) are believed to hold promise as a new therapeutic strategy for multiple human cancers. However, studies on ROS inducers for human thyroid cancer treatment are scarce. This study assesses the anticancer activity and the detailed downstream mechanisms of piperlongumine, a ROS inducer, in human thyroid cancer cells. We demonstrate that piperlongumine inhibits cell proliferation, regulates the cell cycle, and induces cellular apoptosis in various types of human thyroid cancer cells. The antihuman thyroid cancer activity of piperlongumine was through ROS induction, and it further suppressed the downstream Akt signaling pathway to elevate mitochondria-dependent apoptosis. A mouse xenograft study demonstrated that piperlongumine was safe and could inhibit tumorigenesis in vivo. The present study provides strong evidence that piperlongumine can be used as a therapeutic candidate for human thyroid cancers.

Abstract

Thyroid cancer (TC) is the most common endocrine malignancy, and its global incidence has steadily increased over the past 15 years. TC is broadly divided into well-differentiated, poorly differentiated, and undifferentiated types, depending on the histological and clinical parameters. Thus far, there are no effective treatments for undifferentiated thyroid cancers or advanced and recurrent cancer. Therefore, the development of an effective therapeutic is urgently needed for such patients. Piperlongumine (PL) is a naturally occurring small molecule derived from long pepper; it is selectively toxic to cancer cells by generating reactive oxygen species (ROS). In this study, we demonstrate the potential anticancer activity of PL in four TC cell lines. For this purpose, we cultured TC cell lines and analyzed the following parameters: Cell viability, colony formation, cell cycle, apoptosis, and cellular ROS induction. PL modulated the cell cycle, induced apoptosis, and suppressed tumorigenesis in TC cell lines in a dose- and time-dependent manner through ROS induction. Meanwhile, an intrinsic caspase-dependent apoptosis pathway was observed in the TC cells under PL treatment. The activation of Erk and the suppression of the Akt/mTOR pathways through ROS induction were seen in cells treated with PL. PL-mediated apoptosis in TC cells was through the ROS-Akt pathway. Finally, the anticancer effect and safety of PL were also demonstrated in vivo. Our findings indicate that PL exhibits antitumor activity and has the potential for use as a chemotherapeutic agent against TC. This is the first study to show the sensitivity of TC cell lines to PL.

Targeting glioma cells by antineoplastic activity of reversine

Gliomas are the most common type of primary central nervous system tumors and despite great advances in understanding the molecular basis of the disease very few new therapies have been developed. Reversine, a synthetic purine analog, is a multikinase inhibitor that targets aurora kinase A (AURKA) and aurora kinase B (AURKB). In gliomas, a high expression of AURKA or AURKB is associated with a malignant phenotype and a poor prognosis. The present study investigated reversine-related cellular and molecular antiglioma effects in HOG, T98G and U251MG cell lines. Gene and protein expression were assessed by reverse transcription-quantitative PCR and western blotting, respectively. For functional assays, human glioma cell lines (HOG, T98G and U251MG) were exposed to increasing concentrations of reversine (0.4–50 µM) and subjected to various cellular and molecular assays. Reversine reduced the viability and clonogenicity in a dose- and/or time-dependent manner in all glioma cells, with HOG (high AURKB-expression) and T98G (high AURKA-expression) cells being more sensitive compared with U251MG cells (low AURKA- and AURKB-expression). Notably, HOG cells presented higher levels of polyploidy, while T98G presented multiple mitotic spindles, which is consistent with the main regulatory functions of AURKB and AURKA, respectively. In molecular assays, reversine reduced AURKA and/or AURKB expression/activity and increased DNA damage and apoptosis markers, but autophagy-related proteins were not modulated. In conclusion, reversine potently induced mitotic catastrophe and apoptosis in glioma cells and higher basal levels of aurora kinases and genes responsive to DNA damage and may predict improved antiglioma responses to the drug. Reversine may be a potential novel drug in the antineoplastic arsenal against gliomas.

Reversine, a selective MPS1 inhibitor, induced autophagic cell death via diminished glucose uptake and ATP production in cholangiocarcinoma cells

Reversine is a selective inhibitor of mitotic kinase monopolar spindle 1 (MPS1) and has been reported as an anticancer agent in various cancers. The effects of reversine on bile duct cancer, cholangiocarcinoma (CCA), a lethal cancer in Northeastern Thailand, were investigated. This study reports that reversine inhibited cell proliferation of CCA cell lines in dose- and time-dependent manners but had less inhibitory effect on an immortalized cholangiocyte cell line. Reversine also triggered apoptotic cell death by decreasing anti-apoptotic proteins, Bcl-XL and Mcl-1, increasing Bax pro-apoptotic protein and activating caspase-3 activity. Moreover, reversine induced autophagic cell death by increasing LC3-II and Beclin 1 while decreasing p62. Reversine activated autophagy via the AKT signaling pathway. Additionally, this study demonstrated for the first time that reversine could diminish the expression of Hypoxia-Inducible Factor 1- alpha (HIF-1α) and glucose transporter 1 (GLUT1), resulting in a reduction of glucose uptake and energy production in CCA cell lines. These findings suggest that reversine could be a good candidate as an alternative or supplementary drug for CCA treatment.

Reversine exerts cytotoxic effects through multiple cell death mechanisms in acute lymphoblastic leukemia

PURPOSE

Acute lymphoblastic leukemia (ALL) is an aggressive hematological cancer with limited therapeutic options for adult patients. Aurora kinases have drawn attention as potential targets in hematological neoplasms due to their high expression and biological functions. Aurora kinase A (AURKA) and AURKB are essential for a successful mitosis, acting in spindle mitotic organization and cytokinesis. Reversine is a synthetic purine analog that acts as a multi-kinase inhibitor with anti-neoplastic activity by targeting AURKA and AURKB.

METHODS

ALL patient gene expression data were retrieved from the Amazonia!

DATABASE

For functional assays, Jurkat (T-ALL) and Namalwa (B-ALL) cells were exposed to increasing concentrations of reversine and submitted to various cellular and molecular assays.

RESULTS

We found that AURKB expression was higher in ALL patient samples compared to normal lymphocytes (p < 0.0001). The ALL cell lines tested displayed aberrant AURKA and AURKB expression. In Jurkat and Namalwa cells, reversine reduced cell viability in a dose- and time-dependent manner (p < 0.05). Reversine also significantly reduced the viability of primary ALL cells. Reversine induced apoptosis and autophagy, and reduced cell proliferation in both cell lines (p < 0.05). Mitotic catastrophe markers, including cell cycle arrest at G₂/M, increased cell size and DNA damage, were observed upon reversine exposure. Short- and long-term treatment with reversine inhibited autonomous clonogenicity (p < 0.05). At the molecular level, reversine reduced AURKB activity, induced SQSTM1/p62 consumption, and increased LC3BII and γ-H2AX levels. In Namalwa cells, reversine modulated 25 out of 84 autophagy-related genes, including BCL2, BAD, ULK1, ATG10, IRGM and MAP1LC3B, which indicates that reversine acts by initiating and sustaining autophagy signals in ALL cells.

CONCLUSIONS

From our data we conclude that reversine reduces the viability of ALL cells by triggering multiple cell death mechanisms, including apoptosis, mitotic catastrophe, and autophagy. Our findings highlight reversine as a potential anticancer agent for ALL.

Reversine: A Synthetic Purine with a Dual Activity as a Cell Dedifferentiating Agent and a Selective Anticancer Drug

The development of new therapeutic applications for adult and embryonic stem cells has dominated regenerative medicine and tissue engineering for several decades. However, since 2006, induced Pluripotent Stem Cells (iPSCs) have taken center stage in the field, as they promised to overcome several limitations of the other stem cell types. Nonetheless, other promising approaches for adult cell reprogramming have been attempted over the years, even before the generation of iPSCs. In particular, two years before the discovery of iPSCs, the possibility of synthesizing libraries of large organic compounds, as well as the development of high-throughput screenings to quickly test their biological activity, enabled the identification of a 2,6-disubstituted purine, named reversine, which was shown to be able to reprogram adult cells to a progenitor-like state. Since its discovery, the effect of reversine has been confirmed on different cell types, and several studies on its mechanism of action have revealed its central role in inhibitory activity on several kinases implicated in cell cycle regulation and cytokinesis. These key features, together with its chemical nature, suggested a possible use of the molecule as an anti-cancer drug. Remarkably, reversine exhibited potent cytotoxic activity against several tumor cell lines in vitro and a significant effect in decreasing tumor progression and metastatization in vivo. Thus, 15 years since its discovery, this review aims at critically summarizing the current knowledge to clarify the dual role of reversine as a dedifferentiating agent and anti-cancer drug.

Autophagy inhibition by reversine and its suppressive effects on human hepatocellular carcinoma cells

INTRODUCTION

Therapy for human hepatocellular carcinoma (HCC) remains a great challenge for physicians and patients worldwide. The anti-tumor effects of reversine have attracted much more concerns.

MATERIALS AND METHODS

This study evaluated the growth regulatory effects of reversine on HCC cells lines. Meanwhile, the underlying mechanism including autophagy modulation was also identified.

RESULTS

reversine markedly inhibited the proliferation of both HCC cells and induced cell apoptosis and multinuclear in a dose-dependent manner. In addition, the decreased ratio of LC3II/LC3I as well as elevated p62 expression were observed under reversine treatment, indicating the autophagy inhibition by reversine in HepG2 cell line. Moreover, modulation of autophagy with rapamycin and chloroquine significantly attenuated and enhanced the cytostatic effects of reversine, respectively.

CONCLUSIONS

reversine could reduce the cell viability of HCC cells via inducing cell apoptosis and polyploidy. In addition, cell autophagy was involved and might play a protective role in HCC cells, the joint use of autophagy inhibitor enhanced reversine-mediating antitumor effects. Our data offered novel ideas for comprehensive therapeutic regimes on human hepatocellular carcinoma.

Reversine inhibits MMP-3, IL-6 and IL-8 expression through suppression of ROS and JNK/AP-1 activation in interleukin-1β-stimulated human gingival fibroblasts

OBJECTIVE

Periodontitis is an inflammatory disease of the supporting tissue around teeth commonly caused by gram-negative bacterial infections. Interleukin (IL)-1β, a cytokine involved in host immune and inflammatory responses, is known to induce the activation of various intracellular signaling pathways. One of these signaling mechanisms involves the regulation of gene expression by activation of transcription factors (AP-1 and NF-κB). These transcription factors are controlled by mitogen-activated protein kinases (MAPKs), which increase cytokine and matrix metalloproteinase (MMP) expression. We examined the preventive effects of reversine, a 2,6-disubstituted purine derivative, on cytokine and MMP-3 expression in human gingival fibroblasts (HGFs) stimulated with IL-lβ.

STUDY DESIGN

Western blot analyses were performed to verify the activities of MAPK, p65, p50, and c-Jun and the expression of MMPs in IL-1β-stimulated HGFs. Cytokine and MMP-3 expression in IL-1β-stimulated HGFs was measured by real-time quantitative polymerase chain reaction.

RESULTS

Reversine decreased the IL-1β-induced expression of proinflammatory cytokines (IL-6 and IL-8) and MMP-3 in HGFs. Furthermore, the mechanism underlying the effects of reversine involved the suppression of IL-1β-stimulated MAPK activation and AP-1 activation.

CONCLUSION

Reversine inhibits IL-1β-induced MMP and cytokine expression via inhibition of MAPK/AP-1 activation and ROS generation. Therefore, we suggest that reversine may be an effective therapeutic candidate for preventing periodontitis.

Relation of AURKB over-expression to low survival rate in BCRA and reversine-modulated aurora B kinase in breast cancer cell lines

Background

New therapeutic drug for breast cancer (BRCA), especially triple negative BRCA (TNBC), is urgently needed. Even though 2-(4-morpholinoanilino)-6-cyclohexylaminopurine (reversine) is an aurora kinase inhibitor, it also inhibits some cancer cells and human BRCA cells. However, the potential roles of reversine as a novel therapeutic agent for the treatment of BRCA remains unknown and must be further investigation. Thus, the relationship of reversine to aurora kinase in BCRA has not been reported. The relationship between AURKB and survival rate in BRCA has never been reported. Herein, we tested the roles of reversine on different BRCA cell line subtypes. We also investigated the relationship between AURKB and survival rate in BRCA as well as reversine to Aurora kinase expression in BCRA cell lines, including TNBC subtype, 4T1, MDA-MB-231, and luminal subtype MCF-7.

Methods

Cell viability and apoptosis were detected using Cell Counting Kit-8 and flow cytometry analysis, respectively. Apoptotic and tumor-related proteins were tested using Western blot analysis. Important microRNAs that regulate BRCA were analyzed using RT-PCR. UALCAN public databases were used to analyze the targeted gene profiles, and the PROGgeneV2 database was used to study the prognostic implications of genes.

Results

Reversine inhibits cell proliferation and induces cell apoptosis by modulating caspase-3 and bax/bcl-2 among the three cell lines. Data from the UALCAN public database show that BRCA tissues expressed high gene levels of AURKB, TIMP1, MMP9, and TGFB1 compared with the normal tissue. Among the over-expressed genes in BRCA, AURKB ranks 9th in TNBC, 49th in luminal subtype, and 48th in HER2 subtype. High AURKB level in BRCA is highly related to the low survival rate in patients displayed in 18 databases searched via PROGgeneV2. The protein levels of aurora B kinase (Aurora B), which is encoded by AURKB gene, are highly suppressed by reversine in the three cell lines. The tumor-related proteins TGF-β1, TIMP1, and MMP9 are partially suppressed by reversine but with different sensitivity in the three cell lines. The reversine-affected microRNAs, such as miR129-5p, miR-199a-3p, and miR-3960, in MDA-MB-231 cell line might be the research targets in TNBC regulation.

Conclusions

In BRCA, the level of AURKB are over-expressed and is related to low survival rate. Reversine contributes to anti-growth effect in BRCA cell lines, especially for TNBC, by modulating the aurora B. However, the invasiveness, metastasis, and anti-tumor effects of reversine in vivo and in vitro must be further investigated.

Reversine induces caspase-dependent apoptosis of human osteosarcoma cells through extrinsic and intrinsic apoptotic signaling pathways

BACKGROUND

The 2-(4-morpholinoanilino)-6-cyclohexylaminopurine (reversine) acts as a chemopreventive agent and induces apoptotic cell death in various cancer cells. However, the anticancer effects of reversine on osteosarcoma cells are not clearly established.

OBJECTIVE

The purpose of this study was to investigate the effect of reversine on cell proliferation and induction of apoptosis in human osteosarcoma cells.

METHODS

Cell viability assay, histological analysis, DAPI staining, caspase activation analysis, flow cytometric analysis and immunoblotting were carried out in MG-63 osteosarcoma cells.

RESULTS

Reversine inhibited the growth of cells in a dose-dependent manner and induced nuclear condensation and fragmentation. Reversine-treated cells showed caspase-3/7 activation and increased apoptosis versus control cells. FasL, a death ligand associated with extrinsic apoptotic signaling pathways, was significantly up-regulated by reversine treatment. Moreover, the caspase-8, a part of the extrinsic apoptotic pathway, was activated by reversine treatments. Expressions of anti-apoptotic factors such as Bcl-2 and Bcl-xL, components of the mitochondria dependent intrinsic apoptosis pathway, significantly decreased following reversine treatment. The expressions of pro-apoptotic factors such as BAX, BAD and caspase-9 increased by reversine treatments. In addition, reversine activated caspase-3 and Poly (ADP-ribose) polymerase (PARP) to induce cell death. The Z-VAD-fmk significantly inhibited cell death through the suppression of caspase-3 expression in MG-63 cells treated with reversine.

CONCLUSION

These results suggest that the reversine may inhibit cell proliferation and induce apoptotic cell death in MG-63 osteosarcoma cells through both the mitochondria-mediated intrinsic pathway and the death receptor-mediated extrinsic pathway, and may have potential properties for the discovery of anti-cancer agents.

Reversine induces cell cycle arrest and apoptosis via upregulation of the Fas and DR5 signaling pathways in human colorectal cancer cells

Reversine, a 2,6‑diamino‑substituted purine analogue, has been reported to be effective in tumor suppression via induction of cell growth arrest and apoptosis of cancer cells. However, it remains unclear whether reversine exerts anticancer effects on human colorectal cancer cells. In the present study, in vitro experiments were conducted to investigate the anticancer properties of reversine in human colorectal cancer cells. The effect of reversine on human colorectal cancer cell lines, SW480 and HCT‑116, was examined using a WST‑1 cell viability assay, fluorescence microscopy, flow cytometry, DNA fragmentation, small interfering RNA (siRNA) and western blotting. Reversine treatment demonstrated cytotoxic activity in human colorectal cancer cells. It also induced apoptosis by activating poly(ADP‑ribose) polymerase, caspase‑3, ‑7 and ‑8, and increasing the levels of the pro‑apoptotic protein second mitochondria‑derived activator of caspase/direct inhibitor of apoptosis‑binding protein with low pI. The pan‑caspase inhibitor Z‑VAD‑FMK attenuated these reversine‑induced apoptotic effects on human colorectal cancer cells. Additionally, reversine treatment induced cell cycle arrest in the subG1 and G2/M phases via increase in levels of p21, p27 and p57, and decrease in cyclin D1 levels. The expression of Fas and death receptor 5 (DR5) signaling proteins in SW480 and HCT116 cells was upregulated by reversine treatment. Reversine‑induced apoptosis and cell cycle arrest were suppressed by inhibition of Fas and DR5 expression via siRNA. In conclusion, Reversine treatment suppressed tumor progression by the inhibition of cell proliferation, induction of cell cycle arrest and induction of apoptosis via upregulation of the Fas and DR5 signaling pathways in human colorectal cancer cells. The present study indicated that reversine may be used as a novel anticancer agent in human colorectal cancer.

Synthesis of 2,6-Diamino-Substituted Purine Derivatives and Evaluation of Cell Cycle Arrest in Breast and Colorectal Cancer Cells

Reversine is a potent antitumor 2,6-diamino-substituted purine acting as an Aurora kinases inhibitor and interfering with cancer cell cycle progression. In this study we describe three reversine-related molecules, designed by docking calculation, that present structural modifications in the diamino units at positions 2 and 6. We investigated the conformations of the most stable prototropic tautomers of one of these molecules, the N6-cyclohexyl-N6-methyl-N2-phenyl-7H-purine-2,6-diamine (3), by Density Functional Theory (DFT) calculation in the gas phase, water and chloroform, the last solvent considered to give insights into the detection of broad signals in NMR analysis. In all cases the HN(9) tautomer resulted more stable than the HN(7) form, but the most stable conformations changed in different solvents. Molecules 1–3 were evaluated on MCF-7 breast and HCT116 colorectal cancer cell lines showing that, while being less cytotoxic than reversine, they still caused cell cycle arrest in G2/M phase and polyploidy. Unlike reversine, which produced a pronounced cell cycle arrest in G2/M phase in all the cell lines used, similar concentrations of 1–3 were effective only in cells where p53 was deleted or down-regulated. Therefore, our findings support a potential selective role of these structurally simplified, reversine-related molecules in p53-defective cancer cells.

Reversine inhibits Colon Carcinoma Cell Migration by Targeting JNK1

Colorectal cancer is one of the most commonly diagnosed cancers and the third most common cause of cancer-related death. Metastasis is the leading reason for the resultant mortality of these patients. Accordingly, development and characterization of novel anti-cancer drugs limiting colorectal tumor cell dissemination and metastasis are needed. In this study, we found that the small molecule Reversine reduces the migration potential of human colon carcinoma cells in vitro. A coupled kinase assay with bio-informatics approach identified the c-Jun N-terminal kinase (JNK) cascade as the main pathway inhibited by Reversine. Knockdown experiments and pharmacological inhibition identified JNK1 but not JNK2, as a downstream effector target in cancer cell migration. Xenograft experiments confirm the effect of JNK inhibition in the metastatic potential of colon cancer cells. These results highlight the impact of individual JNK isoforms in cancer cell metastasis and propose Reversine as a novel anti-cancer molecule for treatment of colon cancer patients.

Reversine induces autophagic cell death through the AMP-activated protein kinase pathway in urothelial carcinoma cells

Urothelial carcinoma is one of the most common malignancies of the urinary tract. Effective treatment of advanced urothelial carcinoma remains a clinical challenge with poor outcomes in these patients. Previous reports have shown that the expression of aurora kinase is associated with clinical stage and prognosis; hence, aurora kinases are potential targets in urothelial carcinoma therapy. Reversine, an aurora kinase inhibitor, was analyzed for its cytotoxicity in this study. Cell proliferation, flow cytometry, western blotting, and immunofluorescent assay were used to determine the effect of reversine on urothelial carcinoma cells. The results showed that reversine significantly inhibits the growth of urothelial carcinoma cell lines. Reversine induced cell cycle arrest at the G2/M phase, leading to autophagic cell death by activating the AMP-activated protein kinase pathway. Reversine induced significant cell death in urothelial carcinoma cells. Our results suggest that reversine may be a suitably small molecule for treating urothelial carcinoma in the future.

Reversine, a substituted purine, exerts an inhibitive effect on human renal carcinoma cells via induction of cell apoptosis and polyploidy

Background

Human renal cell carcinoma (RCC) is the most common type of kidney cancer that arises from the renal epithelium. Up to 33.3% of RCC patients treated with local tumor resections will subsequently develop recurrence or metastases. Thus, optimized therapeutic regimes are urgently needed to improve the prognosis of RCC. Reversine was recently reported to exert critical roles in cancer therapy.

Materials and methods

This study evaluated the anti-tumor effects of reversine on cell viability, colony formation, apoptosis, and cell cycle in 786-O and ACHN cell lines.

Results

It was demonstrated that reversine significantly inhibited the proliferation of both cell lines in time- and dose-dependent manners. Polyploidy formation was observed under high-concentration reversine treatment. In addition, reversine induced cell death via caspase-dependent apoptotic pathways, which could be partially inhibited by Z-VAD-FMK, a pan-caspase inhibitor.

Conclusion

Reversine could effectively suppress the proliferation of human RCC cells, and may serve as a novel therapeutic regimen for RCC in clinical practice.

Reversine inhibits MMP-1 and MMP-3 expressions by suppressing of ROS/MAPK/AP-1 activation in UV-stimulated human keratinocytes and dermal fibroblasts

UVB has been shown to stimulate the generation of reactive oxygen species (ROS), which subsequently results in the activation of various intracellular signalling pathways and transcription factors (AP-1, NF-κB). These transcription factors are regulated by MAPKs, which increase cytokine and MMP expression. We examined the preventive effects of reversine on MMP-1 and MMP-3 expressions in NHEKs and NHDFs exposed to UVB irradiation. Also, we confirmed that reversine decreased pro-inflammatory cytokine expression in NHEKs. The mechanism underlying the MMP inhibitory effects of reversine occurred via the suppression of UVB-induced ROS generation and MAPK/AP-1 activation. Therefore, reversine is an effective therapeutic candidate for preventing skin photoageing.

Reciprocal Crosstalk Between Autophagic and Endocrine Signaling in Metabolic Homeostasis

Autophagy is a cellular quality control and energy-providing process that is under strict control by intra- and extracellular stimuli. Recently, there has been an exponential increase in autophagy research and its implications for mammalian physiology. Autophagy deregulation is now being implicated in many human diseases, and its modulation has shown promising results in several preclinical studies. However, despite the initial discovery of autophagy as a hormone-regulated process by De Duve in the early 1960s, endocrine regulation of autophagy still remains poorly understood. In this review, we provide a critical summary of our present understanding of the basic mechanism of autophagy, its regulation by endocrine hormones, and its contribution to endocrine and metabolic homeostasis under physiological and pathological settings. Understanding the cross-regulation of hormones and autophagy on endocrine cell signaling and function will provide new insight into mammalian physiology as well as promote the development of new therapeutic strategies involving modulation of autophagy in endocrine and metabolic disorders.

Reversine Induced Multinucleated Cells, Cell Apoptosis and Autophagy in Human Non-Small Cell Lung Cancer Cells

Reversine, an A3 adenosine receptor antagonist, has been shown to induce differentiated myogenic-lineage committed cells to become multipotent mesenchymal progenitor cells. We and others have reported that reversine has an effect on human tumor suppression. This study revealed anti-tumor effects of reversine on proliferation, apoptosis and autophagy induction in human non-small cell lung cancer cells. Treatment of these cells with reversine suppressed cell growth in a time- and dosage-dependent manner. Moreover, polyploidy occurred after reversine treatment. In addition, caspase-dependent apoptosis and activation of autophagy by reversine in a dosage-dependent manner were also observed. We demonstrated in this study that reversine contributes to growth inhibition, apoptosis and autophagy induction in human lung cancer cells. Therefore, reversine used as a potential therapeutic agent for human lung cancer is worthy of further investigation.

Reversine triggers mitotic catastrophe and apoptosis in K562 cells

Chronic myeloid leukemia (CML) is a clonal myeloproliferative neoplasm of the hematopoietic stem cell characterized by presence of the oncoprotein BCR-ABL1, which have constitutive tyrosine kinase activity. BCR-ABL1 activation induces aurora kinase A (AURKA) and aurora kinase B (AURKB) expression, which are serine-threonine kinases that play an important function in chromosome alignment, segregation and cytokinesis during mitosis. Acquisition of resistance to tyrosine kinase inhibitors has emerged as a problem for CML patients and the identification of novel targets with an important contribution for CML phenotype is of interest. In the present study, we explored the cellular effects of reversine, an AURKA and AURKB inhibitor, in the BCR-ABL1+ K562 cells. Our results indicate that reversine reduces AURKA and AURKB expression, leads to reduction of cell viability and increased apoptosis in a dose- and time-dependent manner, as well as, induces mitotic catastrophe in K562 cells. Our preclinical study establishes that reversine presents an effective antileukemia activity against K562 cells and provide new insights on anticancer opportunities for CML.

Hinokitiol induces autophagy in murine breast and colorectal cancer cells

Hinokitiol is found in the heartwood of cupressaceous plants and possesses several biological activities. Hinokitiol may play an important role in anti-inflammation and antioxidant processes, making it potentially useful in therapies for inflammatory-mediated disease. Previously, the suppression of tumor growth by hinokitiol has been shown to occur through apoptosis. Programmed cell death can also occur through autophagy, but the mechanism of hinokitiol-induced autophagy in tumor cells is poorly defined. We used an autophagy inhibitor (3-methyladenine) to demonstrate that hinokitiol can induce cell death via an autophagic pathway. Further, we suggest that hinokitiol induces autophagy in a dose-dependent manner. Markers of autophagy were increased after tumor cells were treated with hinokitiol. In addition, immunoblotting revealed that the levels of phosphoprotein kinase B (P-AKT), phosphomammalian target of rapamycin (P-mTOR), and phospho-p70 ribosomal s6 kinase (P-p70S6K) in tumor cells were decreased after hinokitiol treatment. In conclusion, our results indicate that hinokitiol induces the autophagic signaling pathway via downregulation of the AKT/mTOR pathway. Therefore, our findings show that hinokitiol may control tumor growth by inducing autophagic signaling.

Autophagy in endocrine tumors

Autophagy is an important intracellular process involving the degradation of cytoplasmic components. It is involved in both physiological and pathological conditions, including cancer. The role of autophagy in cancer is described as a 'double-edged sword,' a term that reflects its known participation in tumor suppression, tumor survival and tumor cell proliferation. Available research regarding autophagy in endocrine cancer supports this concept. Autophagy shows promise as a novel therapeutic target in different types of endocrine cancer, inhibiting or increasing treatment efficacy in a context- and cell-type-dependent manner. At present, however, there is very little research concerning autophagy in endocrine tumors. No research was reported connecting autophagy to some of the tumors of the endocrine glands such as the pancreas and ovary. This review aims to elucidate the roles of autophagy in different types of endocrine cancer and highlight the need for increased research in the field.

Autophagy in thyroid cancer: present knowledge and future perspectives

Thyroid cancer is the most common endocrine malignancy. Despite having a good prognosis in the majority of cases, when the tumor is dedifferentiated it does no longer respond to conventional treatment with radioactive iodine, the prognosis worsens significantly. Treatment options for advanced, dedifferentiated disease are limited and do not cure the disease. Autophagy, a process of self-digestion in which damaged molecules or organelles are degraded and recycled, has emerged as an important player in the pathogenesis of different diseases, including cancer. The role of autophagy in thyroid cancer pathogenesis is not yet elucidated. However, the available data indicate that autophagy is involved in several steps of thyroid tumor initiation and progression as well as in therapy resistance and therefore could be exploited for therapeutic applications. The present review summarizes the most recent data on the role of autophagy in the pathogenesis of thyroid cancer and we will provide a perspective on how this process can be targeted for potential therapeutic approaches and could be further explored in the context of multimodality treatment in cancer and personalized medicine.

Autophagy: A potential target for thyroid cancer therapy (Review)

The sharply increasing incidence of thyroid cancer has attracted considerable attention over the last few years. The combination of surgery, radioiodine ablation and thyroid-stimulating hormone suppression is usually efficient for the majority of thyroid tumors. However, advanced thyroid cancer that is recurrent, metastatic and 131I-refractory, or medullary thyroid cancer, pose a therapeutic challenge. Autophagy is a process that metabolizes damaged cytoplasmic organelles and long-lived proteins in order to recycle cellular materials and maintain homeostasis. It has been confirmed that autophagy plays a dual role during cancer development, progression and treatment, mainly depending on the type and stage of the tumor. Autophagy modulation has become a potential therapeutic target for diverse diseases. The mechanism of thyroid tumorigenesis and cancer progression was largely demonstrated to be correlated with the dysregulation of the Ras/Raf/mitogen-activated protein kinase kinase/extracellular signal-regulated kinase and the phosphoinositide 3-kinase/Akt/mammalian target of rapamycin pathways, as well as with abnormal epigenetic modifications. Those mechanisms are associated with autophagy regulation and may be beneficial for the treatment of advanced thyroid cancer. However, the number of available studies on the role of autophagy in thyroid cancer development, progression and treatment outcome, is currently limited. The aim of this review was to elaborate on the relevant knowledge and future prospectives of autophagy in the treatment of thyroid cancer.

Autophagy and thyroid carcinogenesis: genetic and epigenetic links

Thyroid cancer is the most common cancer of the endocrine system and is responsible for the majority of deaths from endocrine malignancies. Although a large proportion of thyroid cancers belong to well differentiated histologic subtypes, which in general show a good prognosis after surgery and radioiodine ablation, the treatment of radio-resistant papillary-type, of undifferentiated anaplastic, and of medullary-type thyroid cancers remains unsatisfactory. Autophagy is a vesicular process for the lysosomal degradation of protein aggregates and of damaged or redundant organelles. Autophagy plays an important role in cell homeostasis, and there is evidence that this process is dysregulated in cancer cells. Recent in vitro preclinical studies have indicated that autophagy is involved in the cytotoxic response to chemotherapeutics in thyroid cancer cells. Indeed, several oncogenes and oncosuppressor genes implicated in thyroid carcinogenesis also play a role in the regulation of autophagy. In addition, some epigenetic modulators involved in thyroid carcinogenesis also influence autophagy. In this review, we highlight the genetic and epigenetic factors that mechanistically link thyroid carcinogenesis and autophagy, thus substantiating the rationale for an autophagy-targeted therapy of aggressive and radio-chemo-resistant thyroid cancers.

Targeting focal adhesion turnover in invasive breast cancer cells by the purine derivative reversine

Background:

The dynamics of focal adhesion (FA) turnover is a key determinant for the regulation of cancer cell migration. Here we investigated FA turnover in a panel of breast cancer models with distinct invasive properties and evaluated the impact of reversine on this turnover in relation to cancer cell invasion in in vitro and in vivo conditions.

Methods:

Live imaging and immunofluorescence assays were used to investigate FA turnover in breast cancer cells. Biochemical studies were used to investigate the impact of reversine on FA signalling and turnover. In vivo activity was investigated using orthotopic breast cancer mouse models.

Results:

Accelerated FA disassembly from plasma membrane protrusions was observed in invasive compared with non-invasive breast cancer cells or non-immortalised mammary epithelial cells. Reversine significantly inhibited FA disassembly leading to stable FAs, which was associated with reduced cell motility and invasion. The inhibitory effect of reversine on FA turnover accounted for a large part on its capacity to interfere with FAK function on regulating its downstream targets. In orthotopic breast cancer mouse models, reversine revealed a potent inhibitory activity on tumour progression to metastasis.

Conclusion:

These results support the utility of targeting FA turnover as a therapeutic approach for invasive breast cancer.