Combination effects of SC144 and cytotoxic anticancer agents

Perspective for Discovery of Small Molecule IL-6 Inhibitors through Study of Structure–Activity Relationships and Molecular Docking

Interleukin-6 (IL-6) is a proinflammatory cytokine that plays a key role in the pathogenesis and physiology of inflammatory and autoimmune diseases, such as coronary heart disease, cancer, Alzheimer's disease, asthma, rheumatoid arthritis, and most recently COVID-19. IL-6 and its signaling pathway are promising targets in the treatment of inflammatory and autoimmune diseases. Although, anti-IL-6 monoclonal antibodies are currently being used in clinics, huge unmet medical needs remain because of the high cost, administration-related toxicity, lack of opportunity for oral dosing, and potential immunogenicity of monoclonal antibody therapy. Furthermore, nonresponse or loss of response to monoclonal antibody therapy has been reported, which increases the importance of optimizing drug therapy with small molecule drugs. This work aims to provide a perspective for the discovery of novel small molecule IL-6 inhibitors by the analysis of the structure-activity relationships and computational studies for protein-protein inhibitors targeting the IL-6/IL-6 receptor/gp130 complex.

Synthesis, Antiproliferative Evaluation, and Molecular Docking Study of Novel Longifolene-Derived Tetraline Fused Thiazole-Amide Derivatives

Twenty novel longifolene-derived tetraline fused thiazole-amide compounds were synthesized from longifolene, a renewable natural resource. Their structures were characterized by FT-IR, NMR, ESI-MS, and elemental analysis. The in vitro antiproliferative activity of these compounds against SK-OV-3 ovarian cancer cell lines, MCF-7 human breast cancer cell lines, HepG2 human liver cancer cell lines, A549 human lung adenocarcinoma cell lines, and T-24 human bladder cancer cell lines was tested by MTT assay. Compounds 6a-6c displayed significant and broad-spectrum antiproliferative activity against almost the tested cancer cell lines with IC₅₀ in the range of 7.84 to 55.88 μM, of which compound 6c exhibited excellent antiproliferative activities with 7.84 μM IC₅₀ against SKOV-3, 13.68 μM IC₅₀ against HepG2, 15.69 μM IC₅₀ against A549, 19.13 μM IC₅₀ against MCF-7, and 22.05 μM IC₅₀ against T-24, showing better and broad-spectrum antiproliferative effect than that of the positive control 5-FU. Furthermore, the action model was analyzed by the molecular docking study. Some intriguing structure-activity relationships were found and discussed herein by DFT theoretical calculation.

Gp130 is expressed in pancreatic cancer and can be targeted by the small inhibitor molecule SC144

PURPOSE

Interleukin 6 (IL-6), Oncostatin M (OSM), and downstream effector STAT3 are pro-tumorigenic agents in pancreatic ductal adenocarcinoma (PDAC). Glycoprotein 130 (gp130) is a compound of the IL-6 and OSM receptor complex that triggers STAT3 signaling. SC144 is a small molecule gp130 inhibitor with anticancer activity. This study examines the gp130 expression in human PDAC specimens and the in vitro effects of SC144 in PDAC cell lines.

METHODS

Tissue micro-arrays were constructed from 175 resected human PDAC. The gp130 expression in tumor epithelium and stroma was determined by immunohistochemistry, and survival analysis was performed. Growth inhibition by SC144 was assessed in vitro using BrdU and MTT assays. Western blotting was performed to evaluate the SC144 effect on IL-6 and OSM signaling.

RESULTS

Gp130 was expressed in the epithelium of 78.8% and the stroma of 9.4% of the tumor samples. The median overall survival for patients with or without epithelial gp130 expression was 16.7 months and 15.9 months, respectively (p = 0.830). Patients with no stromal gp130 expression showed poorer survival than patients with stromal gp130 expression (median 16.2 and 22.9 months, respectively), but this difference did not reach significance (p = 0.144). SC144 inhibited cell proliferation and viability and suppressed IL-6- and OSM-stimulated STAT3^Y705 phosphorylation in PDAC cells.

CONCLUSION

Gp130 is expressed in the epithelium of most human PDAC, but stromal expression is rare. The small molecule gp130 inhibitor SC144 potently inhibits PDAC progression in vitro and may abrogate IL-6 or OSM/gp130/STAT3 signaling. These results suggest gp130 as a novel drug target for pancreatic cancer therapy.

Therapeutic Potential of Thymoquinone in Triple-Negative Breast Cancer Prevention and Progression through the Modulation of the Tumor Microenvironment

To date, the tumor microenvironment (TME) has gained considerable attention in various areas of cancer research due to its role in driving a loss of immune surveillance and enabling rapid advanced tumor development and progression. The TME plays an integral role in driving advanced aggressive breast cancers, including triple-negative breast cancer (TNBC), a pivotal mediator for tumor cells to communicate with the surrounding cells via lymphatic and circulatory systems. Furthermore, the TME plays a significant role in all steps and stages of carcinogenesis by promoting and stimulating uncontrolled cell proliferation and protecting tumor cells from the immune system. Various cellular components of the TME work together to drive cancer processes, some of which include tumor-associated adipocytes, fibroblasts, macrophages, and neutrophils which sustain perpetual amplification and release of pro-inflammatory molecules such as cytokines. Thymoquinone (TQ), a natural chemical component from black cumin seed, is widely used traditionally and now in clinical trials for the treatment/prevention of multiple types of cancer, showing a potential to mitigate components of TME at various stages by various pathways. In this review, we focus on the role of TME in TNBC cancer progression and the effect of TQ on the TME, emphasizing their anticipated role in the prevention and treatment of TNBC. It was concluded from this review that the multiple components of the TME serve as a critical part of TNBC tumor promotion and stimulation of uncontrolled cell proliferation. Meanwhile, TQ could be a crucial compound in the prevention and progression of TNBC therapy through the modulation of the TME.

Activating the interleukin-6-Gp130-STAT3 pathway ameliorates ventricular electrical stability in myocardial infarction rats by modulating neurotransmitters in the paraventricular nucleus

Background

Malignant ventricular arrhythmia (VA) is the most common cause of death associated with acute myocardial infarction (MI). Recent studies have revealed direct involvement of the paraventricular nucleus (PVN) in the occurrence of VA. However, the underlying mechanisms remain incompletely understood. In this study, we investigated changes in the interleukin-6 (IL-6)-glycoprotein 130-signal transducer and activator of transcription 3 (STAT3) pathway in the PVN during acute MI and the effects of this pathway on ventricular stability.

Methods

Rats were divided into a control group, a MI group, a PVN-injected anti-IL-6 antibody group and a PVN-injected SC144 group to observe how IL-6 and its downstream glycoprotein 130-STAT3 pathway in the PVN affect ventricular stability. The left anterior descending coronary artery was ligated to induce MI. After that, an anti-IL-6 antibody and SC144 were injected into the PVNs of rats. All data are expressed as the mean ± SE and were analysed by ANOVA with a post hoc LSD test. p < 0.05 was considered to indicate statistical significance.

Results

After MI, the concentration of the inflammatory factor IL-6 increased, and its downstream glycoprotein 130-STAT3 pathway was activated in the PVN. After injection of MI rat PVNs with the anti-IL-6 antibody or glycoprotein 130 inhibitor (SC144), glutamate levels increased and γ-aminobutyric acid (GABA) levels decreased in the PVN. Plasma norepinephrine concentrations also increased after treatment, which increased the vulnerability to VA.

Conclusions

In summary, IL-6 in the PVN exerts a protective effect in MI rats, and the glycoprotein 130-STAT3 pathway plays a key role in this process. We anticipate that our findings will provide new ideas for the prevention and treatment of arrhythmia after MI.

Dual inhibition of survivin and MAOA synergistically impairs growth of PTEN-negative prostate cancer

Background:

Survivin and monoamine oxidase A (MAOA) levels are elevated in prostate cancer (PCa) compared to normal prostate glands. However, the relationship between survivin and MAOA in PCa is unclear.

Methods:

We examined MAOA expression in the prostate lobes of a conditional PTEN-deficient mouse model mirroring human PCa, with or without survivin knockout. We also silenced one gene at a time and examined the expression of the other. We further evaluated the combination of MAOA inhibitors and survivin suppressants on the growth, viability, migration and invasion of PCa cells.

Results:

Survivin and MAOA levels are both increased in clinical PCa tissues and significantly associated with patients' survival. Survivin depletion delayed MAOA increase during PCa progression, and silencing MAOA decreased survivin expression. The combination of MAOA inhibitors and the survivin suppressants (YM155 and SC144) showed significant synergy on the inhibition of PCa cell growth, migration and invasion with concomitant decrease in survivin and MMP-9 levels.

Conclusions:

There is a positive feedback loop between survivin and MAOA expression in PCa. Considering that survivin suppressants and MAOA inhibitors are currently available in clinical trials and clinical use, their synergistic effects in PCa support a rapid translation of this combination to clinical practice.

Methotrexate and 5-aminoimidazole-4-carboxamide riboside exert synergistic anticancer action against human breast cancer and hepatocellular carcinoma

AIM

To investigate the influences of methotrexate (MTX) on the anticancer actions and pharmacokinetics of 5-aminoimidazole-4-carboxamide riboside (AICA riboside) in human breast cancer and hepatocellular carcinoma.

METHODS

Human breast cancer cell line MCF-7 and human hepatocellular carcinoma cell line HepG2 were examined. The cell proliferation was assessed using a sulforhodamine B assay. Western blotting and radioactivity assays were used to analyze the phosphorylation of AMPK. The DNA synthesis was analyzed with BrdU incorporation. Nude mice bearing MCF-7 cell xenografts were used to for in vivo study. MTX (50 mg/kg, ip, per week) and AICA riboside (200 mg/kg, ip, every other day) were administered the animals for 2 weeks. The concentrations of AICA riboside and its active metabolite AICA ribotide in the plasma and tumors were measured with HPLC.

RESULTS

Synergistic cytotoxicity in vitro was observed with MTX (0.1, 0.5, and 1 μmol/L) combined with AICA riboside (0.25-1 mmol/L) in MCF-7 cells, and with MTX (0.5 and 1 μmol/L) combined with AICA riboside (0.5 and 1 mmol/L) in HepG2 cells. MTX (1 μmol/L) significantly enhanced the AICA riboside-induced AMPK activation and BrdU incorporation in both MCF-7 and HepG2 cells. Co-treatment with MTX and AICA riboside exerted more potent inhibition on the tumor growth in nude mice than either drug alone. After injection of AICA riboside (200 mg/kg, iv) in nude mice bearing MCF-7 xenografts, MTX (50 mg/kg, iv) significantly increased the concentrations of AICA riboside and its active metabolite AICA ribotide in tumors.

CONCLUSION

MTX and AICA riboside exert synergistic anticancer action against MCF-7 and HepG2 cells in vitro and in vivo. MTX increases the concentration of AICA riboside and its active metabolite AICA ribotide in tumors in vivo.