Harmine inhibits the proliferation and migration of glioblastoma cells via the FAK/AKT pathway

Research progress on the antitumor effects of harmine

Harmine is a naturally occurring β-carboline alkaloid originally isolated from Peganum harmala. As a major active component, harmine exhibits a broad spectrum of pharmacological properties, particularly remarkable antitumor effects. Recent mechanistic studies have shown that harmine can inhibit cancer cell proliferation and metastasis through epithelial-to-mesenchymal transition, cell cycle regulation, angiogenesis, and the induction of tumor cell apoptosis. Furthermore, harmine reduces drug resistance when used in combination with chemotherapeutic drugs. Despite its remarkable antitumor activity, the application of harmine is limited by its poor solubility and toxic side effects, particularly neurotoxicity. Novel harmine derivatives have demonstrated strong clinical application prospects, but further validation based on drug activity, acute toxicity, and other aspects is necessary. Here, we present a review of recent research on the action mechanism of harmine in cancer treatment and the development of its derivatives, providing new insights into its potential clinical applications and strategies for mitigating its toxicity while enhancing its efficacy.

The roles of autophagy, ferroptosis and pyroptosis in the anti-ovarian cancer mechanism of harmine and their crosstalk

This study aimed to investigate the role of autophagy, ferroptosis, and pyroptosis in the antitumour mechanism of harmine (Har) and its crosstalk in ovarian cancer. By transmission electron microscopy, we found that compared with those in the control group, the cytoplasm of human ovarian cancer cells (SKOV3) treated with Har showed increased numbers of autophagic vesicles, decreased intracellular mitochondrial volume, increased bilayer membrane density, and decreased cristae. Western blot, immunofluorescence, and monodasylcadaverine (MDC) staining all suggested that Har promoted autophagy in SKOV3 cells. LY294002 and siFOXO3 rescued the inhibition of the PI3K/AKT/mTOR/FOXO3 signalling pathway and the promotion of autophagy by Har. Additionally, the levels of ferroptosis- and pyroptosis-related proteins and the levels of Fe2+ , glutathione (GSH), malondialdehyde (MDA), and superoxide dismutase (SOD) suggested that Har promoted ferroptosis and pyroptosis in SKOV3 cells. Interestingly, pretreatment with chloroquine (CQ), erastin, rapamycin (Rap), or ferrostatin-1 (Fer-1) increased or reversed the ferroptosis and pyroptosis promoted by Har, respectively. In vivo, the volume of tumours in the Har group was decreased, and immunohistochemistry revealed decreased levels of Ki-67 and GPX4 and increased levels of ATG5 and NARL3. In conclusion, Har exerts its anti-ovarian cancer effect not only by promoting autophagy by regulating the PI3K/AKT/mTOR/FOXO3 signalling pathway but also by promoting ferroptosis and pyroptosis. Additionally, there is complex crosstalk between autophagy, ferroptosis, and pyroptosis in ovarian cancer.

Inhibition of Integrin-Associated Kinases FAK and ILK on the In Vitro Model of Skin Wound Healing

Dermal fibroblasts are essential cells of skin tissue responsible for its normal functioning. In skin wounds, the differentiation of resident fibroblasts into myofibroblasts occurs, which is accompanied by the rearrangement of actin cytoskeleton with the expression of alpha-smooth muscle actin. This transformation is a prerequisite for a successful wound healing. At the same time, different studies indicate that extracellular matrix may be involved in regulation of this process. Since the connection between cells and matrix is provided by transmembrane integrin receptors, this work was aimed at studying the dynamics of signaling pathways associated with integrins on an in vitro model of wound healing using human skin fibroblasts. It was shown that the healing of simulated wound was accompanied by a change in the level of integrins as well as integrin-associated kinases ILK (integrin-linked kinase) and FAK (focal adhesion kinase). Pharmacological inhibition of ILK and FAK caused the suppression of p38 and Akt which proteins are involved in regulation of the actin cytoskeleton. Moreover, it resulted in an inefficient wound closure in vitro. The results of this study support the involvement of integrin-associated kinases in regulation of fibroblast-to-myofibroblast transition during wound healing.

Activation of endoplasmic reticulum stress by harmine suppresses the growth of esophageal squamous cell carcinoma

The worldwide overall 5-year survival rate of esophageal squamous cell carcinoma (ESCC) patients is less than 20%, and novel therapeutic strategies for these patients are urgently needed. Harmine is a natural β-carboline alkaloid, which received great interest in cancer research because of its biological and anti-tumor activities. The aim of this study is to examine the effects of harmine on ESCC and its mechanism. We investigated the effects of harmine on proliferation, cell cycle, apoptosis, and tumor growth in vivo. RNA sequencing (RNA-seq), real-time PCR, and western blotting were used to detect the mechanism. Harmine inhibited ESCC cell growth in vitro and tumor growth in vivo. Differentially expressed genes in harmine-treated ESCC cells were mainly involved in protein processing in the endoplasmic reticulum (ER). Real-time PCR and western blotting confirmed harmine-induced cellular ER stress. CRISPR-Cas9 knockout of C/EBP homologous protein (CHOP) abolished harmine-induced expression of death receptor 5 and apoptosis. Harmine also induced the expression of CHOP-mediated sestrin-2, which in turn contributes to autophagosome formation via suppressing the AMP-activated protein kinase-protein kinase B-mammalian target of rapamycin signaling pathway. In conclusion, our results demonstrate that harmine inhibits the growth of ESCC through its regulation of ER stress, suggesting that it is a promising candidate for ESCC treatment.

β-Carboline-α-aminophosphonate Derivative: A Promising Antitumor Agent for Breast Cancer Treatment

Breast cancer is the most common type of cancer and the leading cause of cancer mortality among women worldwide. Considering the limitations of the current treatments available, we analyzed the in vitro cytotoxic potential of ((4-Fluoro-phenyl)-{2-[(1-phenyl-9H-β-carboline-3-carbonyl)-amino]-ethylamino}-methyl)-phosphonic acid dibutyl ester (BCP-1) in breast cancer cells (MCF-7 and MDA-MB-231) and in a non-tumor breast cell line (MCF-10A). BCP-1 has an α-aminophosphonate unit linked to the β-carboline nucleus, and the literature indicates that compounds of these classes have high biological potential. In the present study, the mechanism of action of BCP-1 was investigated through methods of spectrofluorimetry, flow cytometry, and protein expression analysis. It was found that BCP-1 inhibited the proliferation of both cancer cell lines. Furthermore, it induced oxidative stress and cell cycle arrest in G2/M. Upregulation of apoptosis-related proteins such as Bax, cytochrome C, and caspases, as well as a decrease in the anti-apoptotic protein Bcl-2, indicated potential induction of apoptosis in the MDA-MB-231 cells. While in MCF-7 cells, BCP-1 activated the autophagic death pathway, which was demonstrated by an increase in autophagic vacuoles and acidic organelles, in addition to increased expression of LC3I/LC3II and reduced SQSTM1/p62 expression. Further, BCP-1 demonstrated antimetastatic potential by reducing MMP-9 expression and cell migration in both breast cancer cell lines. In conclusion, BCP-1 is a promising candidate for breast cancer chemotherapy.

Harmine exerts anxiolytic effects by regulating neuroinflammation and neuronal plasticity in the basolateral amygdala

Increasing evidence indicates that an altered immune system is closely linked to the pathophysiology of anxiety disorders, and inhibition of neuroinflammation may represent an effective therapeutic strategy to treat anxiety disorders. Harmine, a beta-carboline alkaloid in various medicinal plants, has been widely reported to display anti-inflammatory and potentially anxiolytic effects. However, the exact underlying mechanisms are not fully understood. Our recent study has demonstrated that dysregulation of neuroplasticity in the basolateral amygdala (BLA) contributes to the pathological processes of inflammation-related anxiety. In this study, using a mouse model of anxiety challenged with Escherichia coli lipopolysaccharide (LPS), we found that harmine alleviated LPS-induced anxiety-like behaviors in mice. Mechanistically, harmine significantly prevented LPS-induced neuroinflammation by suppressing the expression of pro-inflammatory cytokines including IL-1β and TNF-α. Meanwhile, ex vivo whole-cell slice electrophysiology combined with optogenetics showed that LPS-induced increase of medial prefrontal cortex (mPFC)-driven excitatory but not inhibitory synaptic transmission onto BLA projection neurons, thereby alleviating LPS-induced shift of excitatory/inhibitory balance towards excitation. In addition, harmine attenuated the increased intrinsic neuronal excitability of BLA PNs by reducing the medium after-hyperpolarization. In conclusion, our findings provide new evidence that harmine may exert its anxiolytic effect by downregulating LPS-induced neuroinflammation and restoring the changes in neuronal plasticity in BLA PNs.

A slow-cycling/quiescent cells subpopulation is involved in glioma invasiveness

Pediatric and adult high-grade gliomas are the most common primary malignant brain tumors, with poor prognosis due to recurrence and tumor infiltration after therapy. Quiescent cells have been implicated in tumor recurrence and treatment resistance, but their direct visualization and targeting remain challenging, precluding their mechanistic study. Here, we identify a population of malignant cells expressing Prominin-1 in a non-proliferating state in pediatric high-grade glioma patients. Using a genetic tool to visualize and ablate quiescent cells in mouse brain cancer and human cancer organoids, we reveal their localization at both the core and the edge of the tumors, and we demonstrate that quiescent cells are involved in infiltration of brain cancer cells. Finally, we find that Harmine, a DYRK1A/B inhibitor, partially decreases the number of quiescent and infiltrating cancer cells. Our data point to a subpopulation of quiescent cells as partially responsible of tumor invasiveness, one of the major causes of brain cancer morbidity.

Quiescent cancer stem cells have been particularly associated to chemoresistance. Here, the authors show that a slowcycling subpopulation in high-grade glioma patients can invade the brain to promote tumourigenesis.

Shikonin inhibits the proliferation of cervical cancer cells via FAK/AKT/GSK3β signalling

Cervical cancer is one of the most lethal malignancies of the female reproductive system. Shikonin, a naphthoquinone pigment extracted from the traditional medicinal herb, Lithospermum erythrorhizon, has been demonstrated to exert significant inhibitory effects on a variety of tumours in vitro and in vivo. In the present study, the effects of shikonin on cervical cancer and the underlying mechanisms were investigated. The effects of shikonin on the viability on HeLa and SiHa cervical cancer cells was examined using cell counting kit (CCK-8) and colony formation assays. Immunofluorescence assay was performed to detect the levels of the proliferation-related protein, Ki67. Western blot analysis was utilized to measure the phosphorylated and total expression levels of proteins, including focal adhesion kinase (FAK), AKT, and glycogen synthase kinase 3β (GSK3β). Cell migration was determined by using wound healing assay. Metastasis-associated 1 (MTA1), TGFβ1 and VEGF mRNA expression levels were determined using reverse transcription-quantitative PCR. It was demonstrated that, shikonin inhibited cervical cancer cell proliferation and migration. The data of the present study revealed that shikonin inhibited the proliferation of HeLa and SiHa cells in a concentration- and time-dependent manner. Mechanistically, shikonin blocked the proliferation of cervical cancer cells by downregulating the phosphorylation of FAK, AKT and GSK3β induced by EGF. In addition, shikonin significantly suppressed cell migration and reduced the expression of migration-related proteins, including MTA1, TGFβ1 and VEGF. On the whole, the present study demonstrates that shikonin may exert an inhibitory effect on the cervical cancer cell proliferation and migration through the FAK/AKT/GSK3β signaling pathway. These findings suggest that shikonin may function as a potential therapeutic drug for the treatment of cervical cancer.

The molecular mechanism of baicalein repressing progression of gastric cancer mediating miR-7/FAK/AKT signaling pathway

BACKGROUND

Baicalein (BAI) has a significant anti-cancerous function in the treatment of gastric cancer (GC). Focal adhesion kinase (FAK) is a key regulatory molecule in integrin and growth factor receptor mediated signaling. MicroRNA-7 (miR-7), has been considered as a potential tumor suppressor in a variety of cancers. However, the possible mechanisms by which BAI inhibiting progression of gastric cancer mediating miR-7/FAK/AKT signaling pathway remain unclear.

PURPOSE

To investigate the molecular mechanism and effects of BAI inhibiting progression of gastric cancer mediating miR-7/FAK/AKT signaling pathway.

METHODS

Gastric cancer cell lines with FAK knockdown and overexpression were constructed by lentivirus transfection. After BAI treatment, the effects of FAK protein on proliferation, metastasis and angiogenesis of gastric cancer cells were detected by MTT, EdU, colony formation, wound healing, transwell and Matrigel tube formation assays. In vivo experiment was performed by xenograft model. Immunofluorescence and western blot assay were used to detect the effects of FAK protein on the expression levels of EMT markers and PI3K/AKT signaling pathway related proteins. qRT-PCR and luciferase reporter assay were used to clarify the targeting relationship between miR-7 and FAK.

RESULTS

BAI can regulate FAK to affect proliferation, metastasis and angiogenesis of gastric cancer cells through PI3K/AKT signaling pathway. qRT-PCR showed BAI can upregulated the expression of miR-7 and luciferase reporter assay showed the targeting relationship between miR-7 and FAK. Additionally, miR-7 mediates cell proliferation, metastasis and angiogenesis by directly targeting FAK 3'UTR to inhibit FAK expression.

CONCLUSION

BAI repressing progression of gastric cancer mediating miR-7/FAK/AKT signaling pathway.

Harmine Alleviated Sepsis-Induced Cardiac Dysfunction by Modulating Macrophage Polarization via the STAT/MAPK/NF-κB Pathway

Sepsis is a dysregulated systemic inflammatory response that often leads to cardiac dysfunction, which is termed sepsis-induced cardiomyopathy (SIC). Harmine, a natural β-carboline alkaloid compound, has been shown to exert pharmacological effects on several diseases. Here, we investigated whether harmine protected against SIC development and the underlying mechanisms. In vitro, the expression of the M1 phenotype markers iNOS and COX-2 was increased in RAW 264.7 cells stimulated with lipopolysaccharide (LPS), but this effect was reversed by the harmine intervention. Furthermore, LPS-induced increases in the levels of inflammatory cytokines, including IL-1β, IL-6, TNF-α, iNOS, COX-2, PGE2 and TXB2, generated by macrophages were suppressed when the cells were pretreated with harmine. Meanwhile, our findings showed that harmine administration effectively attenuated inflammation and apoptosis in H9c2 cells in the proinflammatory environment produced by macrophages, as evidenced by reductions in NLRP3 and cleaved caspase 3 levels and the p-NF-κB/NF-κB ratio. The western blot results indicated that the mechanisms underlying harmine-mediated inhibition of M1 polarization might be associated with suppression of STAT1/3, NF-κB and MAPK activation. Furthermore, an LPS injection induced cardiac dysfunction and decreased the survival rate of mice, which were alleviated by harmine treatment, and the relevant mechanism was possibly attributed to a drug-induced attenuation of the inflammatory and apoptotic processes in cardiomyocytes. Collectively, these results implied that harmine treatment protected against SIC by suppressing M1 phenotypic polarization and inflammation in macrophages.

6-Thioguanine Inhibits Herpes Simplex Virus 1 Infection of Eyes

Herpes simplex virus 1 (HSV-1) infects eye corneal tissues leading to herpetic stromal keratitis (HSK), which is one of the leading causes of blindness. Here in our study, we found that 6-thioguanine (6-TG), a once clinically approved medication for child acute myelogenous leukemia, inhibited multiple strains of HSV-1 infection in vitro and in vivo. 6-TG is more potent than acyclovir (ACV) and ganciclovir (GCV), with the 50% inhibitory concentration (IC₅₀) of 6-TG at 0.104 μM with high stimulation index (SI) (SI = 6,475.48) compared to the IC₅₀ of ACV at 1.253 μM and the IC₅₀ of GCV at 1.257 μM. In addition, 6-TG at 500 μM topically applied to the eyes with HSV-1 infection significantly inhibits HSV-1 replication, alleviates virus-induced HSK pathogenesis, and improves eye conditions. More importantly, 6-TG is effective against ACV-resistant HSV-1 strains, including HSV-1/153 and HSV-1/blue. Knockdown of Rac1 with small interfering RNA (siRNA) negatively affected HSV-1 replication, suggesting that Rac1 facilitated HSV-1 replication. Following HSV-1 infection of human corneal epithelial cells (HCECs), endogenous Rac1 activity was upregulated by glutathione S-transferase (GST) pulldown assay. We further found that Rac1 was highly expressed in the corneal tissue of HSK patients compared to normal individuals. Mechanistic study showed that 6-TG inhibited HSV-1 replication by targeting Rac1 activity in HSV-1 infected cells, and the Rac1 is critical in the pathogenesis of HSK. Our results indicated that 6-TG is a promising therapeutic molecule for the treatment of HSK.

IMPORTANCE We reported the discovery of 6-TG inhibition of HSV-1 infection and its inhibitory roles in HSK both in vitro and in vivo. 6-TG was shown to possess at least 10× more potent inhibitory activity against HSV-1 than ACV and GCV and, more importantly, inhibit ACV/GCV-resistant mutant viruses. Animal model studies showed that gel-formulated 6-TG topically applied to eyes locally infected with HSV-1 could significantly inhibit HSV-1 replication, alleviate virus-induced HSK pathogenesis, and improve eye conditions. Further study showed that HSV-1 infection upregulated Rac1 expression, and knockdown of Rac1 using siRNA markedly restricted HSV-1 replication, suggesting that Rac1 is required for HSV-1 replication. In addition, we also documented that Rac1 is highly expressed in corneal tissues from HSK patients, indicating that Rac1 is associated with HSK pathogenesis. In view of the high potency of 6-TG, low cytotoxicity, targeting a distinct therapeutic target, we suggest that 6-TG is a potential candidate for development as a therapeutic agent for HSK therapy.

Cell-based assays and molecular simulation reveal that the anti-cancer harmine is a specific matrix metalloproteinase-3 (MMP-3) inhibitor

The biological activities of harmine have been a much clearer picture in recent years, which include anti-tumor, anti-inflammation and cytotoxic properties. Numerous in vitro and in vivo animal models have confirmed its activities, but its mode of action remains a relative unsolved issue. We therefore investigated harmine for its effects on MMP-3 and the molecular interaction was also simulated. The human glioma cancer cell line, U-87 MG cells, was subjected to different concentrations (1-10 μM) of harmine for 24 h. Methylthiazol tetrazolium (MTT) test, half maximal inhibitory concentration (IC50), western blot analysis, enzyme-linked immunosorbent assay and molecular docking through BIOVIA DiscoveryStudio™ were performed. These results showed that although harmine stimulation in vitro has very little or no effects on MMP-3 expression by U-87 MG cells, the treatment of harmine decreases MMP-3 activity in a dose dependent manner. It was further calculated that 7.9 μM is the IC50 towards MMP-3. Using a molecular dynamic simulation approach, we identified the N2, methyl of C1 and benzene ring of harmine interact with Zn²⁺ (2.4 Å), His205 (2.4 Å) and His211 (2.4 Å) as well as Val163 (2.7 Å) at the active site of MMP-3, respectively, and thus conferred a striking specific binding advantage. Taken altogether, the present study evidences that harmine acts as an MMP-3 inhibitor specially targeting the enzymatic active site and possibly efficiently ameliorates MMP-3-driven malignant and inflammatory diseases.