Identification of a Novel c-Myc Inhibitor 7594-0037 by Structure-Based Virtual Screening and Investigation of Its Anti-Cancer Effect on Multiple Myeloma

Discovery of 4-(4-(3-(1-(2-(piperidin-1-yl)ethyl)-1H-benzo[d]imidazole-2-yl)isoxazol-5-yl)phenyl)morpholine as a novel c-Myc inhibitor against lung cancer in vitro and in vivo

The critical role of c-Myc as a driving factor in the development and progression of lung cancer establishes it as a pivotal target for anti-lung cancer therapeutic research. In our previous study, we reported on the discovery of D347-2761, a novel small-molecule inhibitor that specifically targets the unstable domain of c-Myc and disrupts the c-Myc/Max heterodimer. To enhance targeted therapies further, we conducted an extensive structural analysis and designed a series of innovative benzimidazole derivatives. The cytotoxic activities of these compounds were assessed using the CCK-8 assay, revealing that compound A1 displayed IC50 values of 6.32 μM and 11.39 μM against the A549 and NCI-H1299 lung cancer cell lines, respectively, while compound A5 exhibited IC50 values of 4.08 μM and 7.86 μM against the same cell lines. Our findings revealed that compounds A1 and A5 exhibited potent anticancer activity by disrupting the interaction between c-Myc and Max proteins, leading to the downregulation of c-Myc protein levels and induction of apoptosis through apoptotic pathways. Notably, compound A5 demonstrated superior inhibitory capacity compared to other compounds tested. Furthermore, in a syngeneic tumor model, compound A5 exhibited excellent efficacy with a tumor growth inhibition rate reaching up to 76.4 %, accompanied by a significant reduction in c-Myc protein expression levels. Therefore, compound A5 holds promise as a potential agent for targeting c-Myc in anti-lung cancer therapy.

Design, synthesis, and activity evaluation of 2-iminobenzimidazoles as c-Myc inhibitors for treating multiple myeloma

Multiple myeloma (MM) is a plasma cell malignancy that remains incurable and poses a significant threat to global public health. The multifunctional transcription factor c-Myc plays a crucial role in various cellular processes and is closely associated with MM progression. As part of the basic-helix-loop-helix-leucine zipper (bHLHZip) family, c-Myc forms heterodimers with its obligate partner Max, binds to the Enhancer-box (E-box) of DNA, and ultimately co-regulates gene expression. Therefore, impeding the capacity for heterodimerization to bind to DNA represents a favored strategy in thwarting c-Myc transcription. In this study, we first synthesized a series of novel 2-iminobenzimidazole derivatives and further estimated their potential anti-MM activity. Notably, among all the derivatives, 5b and 5d demonstrated remarkable inhibitory activity against RPMI-8226 and U266 cells, with IC50 values of 0.85 μM and 0.97 μM for compound 5b, and 0.96 μM and 0.89 μM for compound 5d. Western blot and dual-luciferase reporter assays demonstrated that compounds 5b and 5d effectively suppressed both c-Myc protein expression and transcriptional activity of the c-Myc promoter in RPMI-8226 and U266 cells. Furthermore, these compounds induced apoptosis and G1 cell cycle arrest in the aforementioned MM cells. Molecular docking studies revealed that 5b and 5d exhibited strong binding affinity to the interface between c-Myc/Max and E-box of DNA. Taken together, our findings suggest that further investigations are warranted for potential therapeutic applications of 5b and 5d for c-Myc-related diseases.

Novel c-Myc G4 stabilizer EP12 promotes myeloma cytotoxicity by disturbing NF-κB signaling

Multiple myeloma (MM) is a B-cell malignancy characterized by the excessive proliferation of bone marrow plasma cells and the production of abnormal immunoglobulins. Despite advances in therapeutic strategies, it remains an incurable disease. Recently, innovative anticancer drugs have been developed and approved, leading to improvements in MM therapy; however, drug resistance continues to be a major obstacle that results in treatment failure. Therefore, the development of novel agents is imperative to achieve superior therapeutic outcomes for relapsed/refractory multiple myeloma (MM) patients. Previously, we identified EP12 as a c-Myc G4 stabilizer that could induce cytotoxicity in MM cells in vitro. However, further investigation is required to elucidate the underlying molecular mechanisms and anti-MM activity of EP12 in vivo. In this study, we have discovered that the compound EP12 effectively inhibits primary myeloma growth in vivo by destabilizing c-Myc and disrupting the canonical nuclear factor-κB (NF-κB) signaling pathway. Overall, our findings suggest that EP12, as a potent c-Myc inhibitor, holds great promise as a therapeutic agent for MM.

Pim-2 Kinase Regulates Energy Metabolism in Multiple Myeloma

Pim-2 kinase is overexpressed in multiple myeloma (MM) and is associated with poor prognosis in patients with MM. Changes in quantitative metabolism, glycolysis, and oxidative phosphorylation pathways are reportedly markers of all tumor cells. However, the relationship between Pim-2 and glycolysis in MM cells remains unclear. In the present study, we explored the relationship between Pim-2 and glycolysis. We found that Pim-2 inhibitors inhibited glycolysis and energy production in MM cells. Inhibition of Pim-2 decreased the proliferation of MM tumor cells and increased their susceptibility to apoptosis. Our data suggest that reduced Pim-2 expression inhibits the energy metabolism process in MM, thereby inhibiting tumor progression. Hence, Pim-2 is a potential metabolic target for MM treatment.

Epithelial Cell Adhesion Molecule (EpCAM) Expression Can Be Modulated via NFκB

The epithelial cell adhesion molecule (EpCAM) is considered an essential proliferation signature in cancer. In the current research study, qPCR induced expression of EpCAM was noted in acute lymphoblastic leukemia (ALL) cases. Costunolide, a sesquiterpene lactone found in crepe ginger and lettuce, is a medicinal herb with anticancer properties. Expression of EpCAM and its downstream target genes (Myc and TERT) wasdownregulated upon treatment with costunolide in Jurkat cells. A significant change in the telomere length of Jurkat cells was not noted at 72 h of costunolide treatment. An in silico study revealed hydrophobic interactions between EpCAM extracellular domain and Myc bHLH with costunolide. Reduced expression of NFκB, a transcription factor of EpCAM, Myc, and TERT in costunolide-treated Jurkat cells, suggested that costunolide inhibits gene expression by targeting NFκB and its downstream targets. Overall, the study proposes that costunolide could be a promising therapeutic biomolecule for leukemia.

Novel dual-targeting c-Myc inhibitor D347-2761 represses myeloma growth via blocking c-Myc/Max heterodimerization and disturbing its stability

Background

Transcription factor c-Myc plays a critical role in various physiological and pathological events. c-Myc gene rearrangement is closely associated with multiple myeloma (MM) progression and drug resistance. Thereby, targeting c-Myc is expected to be a useful therapeutic strategy for hematological disease, especially in MM.

Methods

Molecular docking-based virtual screening and dual-luciferase reporter gene assay were used to identify novel c-Myc inhibitors. Cell viability and flow cytometry were performed for evaluating myeloma cytotoxicity. Western blot, immunofluorescence, immunoprecipitation, GST pull down and Electrophoretic Mobility Shift Assay were performed for protein expression and interaction between c-Myc and Max. c-Myc downstream targets were measured by Q-PCR and Chromatin immunoprecipitation methods. Animal experiments were used to detect myeloma xenograft and infiltration in vivo.

Results

We successfully identified a novel c-Myc inhibitor D347-2761, which hindered the formation of c-Myc/Max heterodimer and disturbed c-Myc protein stability simultaneously. Compound D347-2761 dose-and time-dependently inhibited myeloma cell proliferation and induced apoptosis. Dual knockout Bak/Bax partially restored D347-2761-mediated cell death. Additionally, compound D347-2761 could, in combination with bortezomib (BTZ), enhance MM cell DNA damage and overcome BTZ drug resistance. Our in vivo studies also showed that compound D347-2761 repressed myeloma growth and distal infiltration by downregulating c-Myc expression. Mechanistically, novel dual-targeting c-Myc inhibitor D347-2761 promoted c-Myc protein degradation via stimulating c-Myc Thr58 phosphorylation levels, which ultimately led to transcriptional repression of CDK4 promoter activity.

Conclusions

We identified a novel dual-targeting c-Myc small molecular inhibitor D347-2761. And this study may provide a solid foundation for developing a novel therapeutic agent targeting c-Myc.

Quercetin Attenuates Podocyte Apoptosis of Diabetic Nephropathy Through Targeting EGFR Signaling

Podocytes injury is one of the leading causes of proteinuria in patients with diabetic nephropathy (DN), and is accompanied by podocytes apoptosis and the reduction of podocyte markers such as synaptopodin and nephrin. Therefore, attenuation of podocyte apoptosis is considered as an effective strategy to prevent the proteinuria in DN. In this study, we evaluated the anti-podocyte-apoptosis effect of quercetin which is a flavonol compound possessing an important role in prevention and treatment of DN and verified the effect by using db/db mice and high glucose (HG)-induced mouse podocytes (MPs). The results show that administration of quercetin attenuated the level of podocyte apoptosis by decreasing the expression of pro-apoptotic protein Bax, cleaved caspase 3 and increasing the expression of anti-apoptotic protein Bcl-2 in the db/db mice and HG-induced MPs. Furthermore, epidermal growth factor receptor (EGFR) was predicted to be the potential physiological target of quercetin by network pharmacology. In vitro and vivo experiments confirmed that quercetin inhibited activation of the EGFR signaling pathway by decreasing phosphorylation of EGFR and ERK1/2. Taken together, this study demonstrates that quercetin attenuated podocyte apoptosis through inhibiting EGFR signaling pathway, which provided a novel approach for further research of the mechanism of quercetin in the treatment of DN.

Targeted therapy of multiple myeloma

Multiple myeloma (MM) is a malignant proliferative disease of monoclonal plasma cells (PCs) and is characterized by uncontrolled proliferation of PCs and excessive production of specific types of immunoglobulins. Since PCs are terminally differentiated B cells, the World Health Organization (WHO) classifies MM as lymphoproliferative B-cell disease. The incidence of MM is 6-7 cases per 100,000 people in the world every year and the second most common cancer in the blood system. Due to the effects of drug resistance and malignant regeneration of MM cells in the microenvironment, all current treatment methods can prolong both overall and symptom-free survival rates of patients with MM but cannot cure MM. Both basic and clinical studies have proven that targeted therapy leads to a clear and significant prolongation of the survival of patients with MM, but when the disease recurs again, resistance to the previous treatment will occur. Therefore, the discovery of new targets and treatment methods plays a vital role in the treatment of MM. This article introduces and summarizes targeted MM therapy, potential new targets, and future precision medicine in MM.

MYC inhibitors in multiple myeloma

The importance of MYC function in cancer was discovered in the late 1970s when the sequence of the avian retrovirus that causes myelocytic leukemia was identified. Since then, over 40 years of unceasing research have highlighted the significance of this protein in malignant transformation, especially in hematologic diseases. Indeed, some of the earliest connections among the higher expression of proto-oncogenes (such as MYC), genetic rearrangements and their relation to cancer development were made in Burkitt lymphoma, chronic myeloid leukemia and mouse plasmacytomas. Multiple myeloma (MM), in particular, is a plasma cell malignancy strictly associated with MYC deregulation, suggesting that therapeutic strategies against it would be beneficial in treating this disease. However, targeting MYC was - and, somehow, still is - challenging due to its unique properties: lack of defined three-dimensional structure, nuclear localization and absence of a targetable enzymatic pocket. Despite these difficulties, however, many studies have shown the potential therapeutic impact of direct or indirect MYC inhibition. Different molecules have been tested, in fact, in the context of MM. In this review, we summarize the current status of the different compounds, including the results of their clinical testing, and propose to continue with the efforts to identify, repurpose, redesign or improve drug candidates to combine them with standard of care therapies to overcome resistance and enable better management of myeloma treatment.

Design, Synthesis and Pharmacological Evaluation of Naphthofuran Derivatives as Potent SIRT1 Activators

Diabetic nephropathy (DN) is one of the most important medical complications in diabetic patients, which is an essential cause of end-stage renal disease in diabetic patients and still lacks effective medicines. Silent information regulator 1 (SIRT1) is closely related to the occurrence and development of DN. Activation of SIRT1 could significantly improve the symptoms of DN, while the activities of SIRT1 activators need to be further improved. Based on the crystal structure of SIRT1, structure and ligand-based approaches were carried out, and a lead compound 4,456–0661 (renamed as M1) was identified. Moreover, seven M1 analogues (6a-6g) were designed using a structure-based drug design strategy followed by bioactivity evaluation with SRTR2104 used as positive drugs. Among the target molecules, compounds M1, 6b, and 6d were proved to be potent SIRT1 activators, the activities of which are comparable to SRT2104. More importantly, compounds M1, 6b, and 6d could resist high glucose-induced apoptosis of HK-2 cells by activating SIRT1 and deacetylation of p53. Apart from the beneficial effect on apoptosis of DN, these compounds also alleviated high glucose stimulating inflammation response in HK-2 cells through SIRT1/NF-κB (p65) pathway. Consequently, M1, 6b, and 6d could be promising drug candidates for SIRT1 related diseases.