Cinnamaldehyde causes apoptosis of myeloid-derived suppressor cells through the activation of TLR4

The role and mechanism of cinnamaldehyde in cancer

As cancer continues to rise globally, there is growing interest in discovering novel methods for prevention and treatment. Due to the limitations of traditional cancer therapies, there has been a growing emphasis on investigating herbal remedies and exploring their potential synergistic effects when combined with chemotherapy drugs. Cinnamaldehyde, derived from cinnamon, has gained significant attention for its potential role in cancer prevention and treatment. Extensive research has demonstrated that cinnamaldehyde exhibits promising anticancer properties by modulating various cellular processes involved in tumor growth and progression. However, challenges and unanswered questions remain regarding the precise mechanisms for its effective use as an anticancer agent. This article aims to explore the multifaceted effects of cinnamaldehyde on cancer cells and shed light on these existing issues. Cinnamaldehyde has diverse anti-cancer mechanisms, including inducing apoptosis by activating caspases and damaging mitochondrial function, inhibiting tumor angiogenesis, anti-proliferation, anti-inflammatory and antioxidant. In addition, cinnamaldehyde also acts as a reactive oxygen species scavenger, reducing oxidative stress and preventing DNA damage and genomic instability. This article emphasizes the promising therapeutic potential of cinnamaldehyde in cancer treatment and underscores the need for future research to unlock novel mechanisms and strategies for combating cancer. By providing valuable insights into the role and mechanism of cinnamaldehyde in cancer, this comprehensive understanding paves the way for its potential as a novel therapeutic agent. Overall, cinnamaldehyde holds great promise as an anticancer agent, and its comprehensive exploration in this article highlights its potential as a valuable addition to cancer treatment options.

The Therapeutic Roles of Cinnamaldehyde against Cardiovascular Diseases

Evidence from epidemiological studies has demonstrated that the incidence and mortality of cardiovascular diseases (CVDs) increase year by year, which pose a great threat on social economy and human health worldwide. Due to limited therapeutic benefits and associated adverse effects of current medications, there is an urgent need to uncover novel agents with favorable safety and efficacy. Cinnamaldehyde (CA) is a bioactive phytochemical isolated from the stem bark of Chinese herbal medicine Cinnamon and has been suggested to possess curative roles against the development of CVDs. This integrated review intends to summarize the physicochemical and pharmacokinetic features of CA and discuss the recent advances in underlying mechanisms and potential targets responsible for anti-CVD properties of CA. The CA-related cardiovascular protective mechanisms could be attributed to the inhibition of inflammation and oxidative stress, improvement of lipid and glucose metabolism, regulation of cell proliferation and apoptosis, suppression of cardiac fibrosis, and platelet aggregation and promotion of vasodilation and angiogenesis. Furthermore, CA is likely to inhibit CVD progression via affecting other possible processes including autophagy and ER stress regulation, gut microbiota and immune homeostasis, ion metabolism, ncRNA expression, and TRPA1 activation. Collectively, experiments reported previously highlight the therapeutic effects of CA and clinical trials are advocated to offer scientific basis for the compound future applied in clinical practice for CVD prophylaxis and treatment.

HSP90α induces immunosuppressive myeloid cells in melanoma via TLR4 signaling

Background

Tumor cells modulate host immunity by secreting extracellular vesicles (EV) and soluble factors. Their interactions with myeloid cells lead to the generation of myeloid-derived suppressor cells (MDSC), which inhibit the antitumor function of T and NK cells. We demonstrated previously that EV derived from mouse and human melanoma cells induced immunosuppressive activity via increased expression of programmed cell death ligand 1 (PD-L1) on myeloid cells that was dependent on the heat-shock protein 90α (HSP90α) in EV. Here, we investigated whether soluble HSP90α could convert monocytes into MDSC.

Methods

CD14 monocytes were isolated from the peripheral blood of healthy donors, incubated with human recombinant HSP90α (rHSP90α) alone or in the presence of inhibitors of TLR4 signaling and analyzed by flow cytometry. Inhibition of T cell proliferation assay was applied to assess the immunosuppressive function of rHSP90α-treated monocytes. HSP90α levels were measured by ELISA in plasma of patients with advanced melanoma and correlated with clinical outcome.

Results

We found that the incubation of monocytes with rHSP90α resulted in a strong upregulation of PD-L1 expression, whereas reactive oxygen species (ROS) and nitric oxide (NO) production as well as the expression of arginase-1, ectoenzymes CD39 and CD73 remained unchanged. The PD-L1 upregulation was blocked by anti-TLR4 antibodies and a nuclear factor-κB inhibitor. rHSP90α-treated monocytes displayed the downregulation of HLA-DR expression and acquired the resistance to apoptosis. Moreover, these monocytes were converted into MDSC as indicated by their capacity to inhibit T cell proliferation, which was mediated by TLR4 signaling as well as PD-L1 and indoleamine 2,3-dioxygenase (IDO) 1 expression. Higher levels of HSP90α in plasma of patients with melanoma correlated with augmented PD-L1 expression on circulating monocytic (M)-MDSC. Patients with melanoma with high levels of HSP90α displayed shorter progression-free survival (PFS) on the treatment with immune checkpoint inhibitors (ICIs).

Conclusion

Our findings demonstrated that soluble rHSP90α increased the resistance of normal human monocytes to apoptosis and converted them into immunosuppressive MDSC via TLR4 signaling that stimulated PD-L1 and IDO-1 expression. Furthermore, patients with melanoma with high concentrations of HSP90α displayed increased PD-L1 expression on M-MDSC and reduced PFS after ICI therapy, suggesting HSP90α as a promising therapeutic target for overcoming immunosuppression in melanoma.

Pharmacological modulation of myeloid-derived suppressor cells to dampen inflammation

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous cell population with potent suppressive and regulative properties. MDSCs’ strong immunosuppressive potential creates new possibilities to treat chronic inflammation and autoimmune diseases or induce tolerance towards transplantation. Here, we summarize and critically discuss different pharmacological approaches which modulate the generation, activation, and recruitment of MDSCs in vitro and in vivo, and their potential role in future immunosuppressive therapy.

Strategies for Biomaterial-Based Spinal Cord Injury Repair via the TLR4-NF-κB Signaling Pathway

The repair and motor functional recovery after spinal cord injury (SCI) has remained a clinical challenge. Injury-induced gliosis and inflammation lead to a physical barrier and an extremely inhibitory microenvironment, which in turn hinders the recovery of SCI. TLR4-NF-κB is a classic implant-related innate immunomodulation signaling pathway and part of numerous biomaterial-based treatment strategies for SCI. Numerous experimental studies have demonstrated that the regulation of TLR4-NF-κB signaling pathway plays an important role in the alleviation of inflammatory responses, the modulation of autophagy, apoptosis and ferroptosis, and the enhancement of anti-oxidative effect post-SCI. An increasing number of novel biomaterials have been fabricated as scaffolds and carriers, loaded with phytochemicals and drugs, to inhibit the progression of SCI through regulation of TLR4-NF-κB. This review summarizes the empirical strategies for the recovery after SCI through individual or composite biomaterials that mediate the TLR4-NF-κB signaling pathway.

Cinnamaldehyde Downregulation of Sept9 Inhibits Glioma Progression through Suppressing Hif-1α via the Pi3k/Akt Signaling Pathway

Purpose

Cinnamaldehyde (CA) is the main ingredient in cinnamon, and it has been proven to have an inhibitory effect on many different tumor types. However, it lacks effect on glioma. This paper explores the effect CA has on glioma cells U87 and U251 at the cellular and molecular levels.

Methods

The relationship between Hif-1α and Sept9 was found by CGGA. Cell Viability Assay (CCK8) was made to detect the proliferation ability. The scratch experiment and the transwell experiment were applied to the migration and invasion ability. Annexin V-FITC/PI were used to detect the cell apoptosis. Western blotting was used to determine the specified protein level.

Results

Cell proliferation assay results revealed CA to inhibit the proliferation of glioma cells in a dose-dependent manner. It promoted apoptosis for upregulating the expression of Bax and downregulating the expression of Bcl-2. Wound Healing Assay and transwell test found CA to have anti-invasion ability and that it upregulated the expression of E-cadherin and downregulated the expressions of MMP-2 and MMP-9. The molecular mechanism was studied from a tumor microenvironment (TME) perspective. Pi3k inhibitor (LY294002) was used for interfering with cells, and the results found CA to demonstrate a similar effect. Hif-1α and Sept9 expressions were inhibited, and Akt and p-Akt were also inhibited. By using CoCl₂ to make hypoxia, CA was discovered to inhibit the high expression of Hif-1α and Sept9, demonstrating a correlation with the Pi3k/Akt pathway. It is suggested that the mechanism of Sept9 under hypoxia regulation can be realized through the Pi3k/Akt pathway.

Conclusions

This study proves for the first time that CA is an effective drug for inhibiting the proliferation of glioma through Sept9 and reveals Sept9 to be related to the Pi3k/Akt pathway in terms of tumor microenvironment, providing a molecular basis for the further study of CA in glioma treatment.

Toll-like Receptor 4 Inhibitor TAK-242 Improves Fulminant Hepatitis by Regulating Accumulation of Myeloid-Derived Suppressor Cell

Fulminant hepatitis (FH) is an acute clinical disease with a poor prognosis and high mortality rate. The purpose of this study was to determine the protective effect of the Toll-like receptor 4 (TLR4) inhibitor TAK-242 on lipopolysaccharide (LPS)/D-galactosamine (D-GalN)-induced explosive hepatitis and explore in vivo and in vitro mechanisms. Mice were pretreated with TAK-242 for 3 h prior to LPS (10 μg/kg)/D-GalN (250 mg/kg) administration. Compared to the LPS/D-GalN group, the TAK-242 pretreatment group showed significantly prolonged survival, reduced serum alanine aminotransferase and aspartate aminotransferase levels, relieved oxidative stress, and reduced inflammatory interleukin (IL)-6, IL-12, and tumor necrosis factor-α levels. In addition, TAK-242 increased the accumulation of myeloid-derived suppressor cells (MDSCs). Next, mice were treated with an anti-Gr-1 antibody to deplete MDSCs, and adoptive transfer experiments were performed. We found that TAK-242 protected against FH by regulating MDSCs. In the in vitro studies, TAK-242 regulated the accumulation of MDSCs and promoted the release of immunosuppressive inflammatory cytokines. In addition, TAK-242 inhibited protein expression of nuclear factor-κB and mitogen-activated protein kinases. In summary, TAK-242 had a hepatoprotective effect against LPS/D-GalN-induced explosive hepatitis in mice. Its protective effect may be involved in suppressing inflammation, reducing oxidative stress, and increasing the proportion of MDSCs.

Cinnamaldehyde and Hyperthermia Co-Treatment Synergistically Induces ROS-Mediated Apoptosis in ACHN Renal Cell Carcinoma Cells

Renal cell carcinoma (RCC) represents the most common form of kidney cancer, which accounts for 3-5% newly diagnosed cancer cases. Since limited therapies are available for RCC, a search for new options is required. Therefore, in this study, we evaluated the combination effect of cinnamaldehyde (CNM) and hyperthermia treatment. CNM treatment combined with 43 °C hyperthermia synergistically increased cytotoxicity in RCC cell line ACHN cells. Through Western blot assays, we observed increased apoptosis signaling and decreased proliferation/metastasis signaling, along with a repressed heat shock protein 70 level. In flow cytometry analyses, CNM and hyperthermia combination clearly induced apoptosis and mitochondrial potential of ACHN cells, while arresting the cell cycle. Investigation of reactive oxygen species (ROS) suggested a significant increase of ROS generation by CNM and 43 °C hyperthermia co-treatment. We could verify that ROS is crucial in the apoptotic action of combination treatment with CNM and hyperthermia through further experiments regarding an ROS scavenger. Overall, we suggest CNM and hyperthermia combination treatment as an alternative option of anticancer strategies for RCC.

Chemopreventive and Therapeutic Efficacy of Cinnamomum zeylanicum L. Bark in Experimental Breast Carcinoma: Mechanistic In Vivo and In Vitro Analyses

Comprehensive oncology research suggests an important role of phytochemicals or whole plant foods in the modulation of signaling pathways associated with anticancer action. The goal of this study is to assess the anticancer activities of Cinnamomum zeylanicum L. using rat, mouse, and cell line breast carcinoma models. C. zeylanicum (as bark powder) was administered in the diet at two concentrations of 0.1% (w/w) and 1% (w/w) during the whole experiment in chemically induced rat mammary carcinomas and a syngeneic 4T1 mouse model. After autopsy, histopathological and molecular evaluations of mammary gland tumors in rodents were carried out. Moreover, in vitro analyses using MCF-7 and MDA-MB-231 cells were performed. The dominant metabolites present in the tested C. zeylanicum essential oil (with relative content over 1%) were cinnamaldehyde, cinnamaldehyde dimethyl acetal, cinnamyl acetate, eugenol, linalool, eucalyptol, limonene, o-cymol, and α-terpineol. The natural mixture of mentioned molecules demonstrated significant anticancer effects in our study. In the mouse model, C. zeylanicum at a higher dose (1%) significantly decreased tumor volume by 44% when compared to controls. In addition, treated tumors showed a significant dose-dependent decrease in mitotic activity index by 29% (0.1%) and 45.5% (1%) in comparison with the control group. In rats, C. zeylanicum in both doses significantly reduced the tumor incidence by 15.5% and non-significantly suppressed tumor frequency by more than 30% when compared to controls. An evaluation of the mechanism of anticancer action using valid oncological markers showed several positive changes after treatment with C. zeylanicum. Histopathological analysis of treated rat tumor specimens showed a significant decrease in the ratio of high-/low-grade carcinomas compared to controls. In treated rat carcinomas, we found caspase-3 and Bax expression increase. On the other hand, we observed a decrease in Bcl-2, Ki67, VEGF, and CD24 expressions and MDA levels. Assessment of epigenetic changes in rat tumor cells in vivo showed a significant decrease in lysine methylation status of H3K4m3 and H3K9m3 in the high-dose treated group, a dose-dependent increase in H4K16ac levels (H4K20m3 was not changed), down-regulations of miR21 and miR155 in low-dose cinnamon groups (miR22 and miR34a were not modulated), and significant reduction of the methylation status of two out of five gene promoters-ATM and TIMP3 (PITX2, RASSF1, PTEN promoters were not changed). In vitro study confirmed results of animal studies, in that the essential oil of C. zeylanicum displayed significant anticancer efficacy in MCF-7 and MDA-MB-231 cells (using MTS, BrdU, cell cycle, annexin V/PI, caspase-3/7, Bcl-2, PARP, and mitochondrial membrane potential analyses). As a conclusion, C. zeylanicum L. showed chemopreventive and therapeutic activities in animal breast carcinoma models that were also significantly confirmed by mechanistic evaluations in vitro and in vivo.