Cetuximab enhances oridonin-induced apoptosis through mitochondrial pathway and endoplasmic reticulum stress in laryngeal squamous cell carcinoma cells

Therapeutic Potential of Terpenoids in Cancer Treatment: Targeting Mitochondrial Pathways

BACKGROUND

In recent decades, natural compounds have been considered a significant source of new antitumor medicines due to their unique advantages. Several in vitro and in vivo studies have focused on the effect of terpenoids on apoptosis mediated by mitochondria in malignant cells.

RECENT FINDINGS

In this review article, we focused on six extensively studied terpenoids, including sesquiterpenes (dihydroartemisinin and parthenolide), diterpenes (oridonin and triptolide), and triterpenes (betulinic acid and oleanolic acid), and their efficacy in targeting mitochondria to induce cell death. Terpenoid-induced mitochondria-related cell death includes apoptosis, pyroptosis, necroptosis, ferroptosis, autophagy, and necrosis caused by mitochondrial permeability transition. Apoptosis and autophagy interact in meaningful ways. In addition, in view of several disadvantages of terpenoids, such as low stability and bioavailability, advances in research on combination chemotherapy and chemical modification were surveyed.

CONCLUSION

This article deepens our understanding of the association between terpenoids and mitochondrial cell death, presenting a hypothetical basis for the use of terpenoids in anticancer management.

Endoplasmic reticulum stress-a key guardian in cancer

Endoplasmic reticulum stress (ERS) is a cellular stress response characterized by excessive contraction of the endoplasmic reticulum (ER). It is a pathological hallmark of many diseases, such as diabetes, obesity, and neurodegenerative diseases. In the unique growth characteristic and varied microenvironment of cancer, high levels of stress are necessary to maintain the rapid proliferation and metastasis of tumor cells. This process is closely related to ERS, which enhances the ability of tumor cells to adapt to unfavorable environments and promotes the malignant progression of cancer. In this paper, we review the roles and mechanisms of ERS in tumor cell proliferation, apoptosis, metastasis, angiogenesis, drug resistance, cellular metabolism, and immune response. We found that ERS can modulate tumor progression via the unfolded protein response (UPR) signaling of IRE1, PERK, and ATF6. Targeting the ERS may be a new strategy to attenuate the protective effects of ERS on cancer. This manuscript explores the potential of ERS-targeted therapies, detailing the mechanisms through which ERS influences cancer progression and highlighting experimental and clinical evidence supporting these strategies. Through this review, we aim to deepen our understanding of the role of ER stress in cancer development and provide new insights for cancer therapy.

Suppression of PERK/eIF2α/CHOP pathway enhances oridonin-induced apoptosis by inhibiting autophagy in Small-Cell lung cancer cells

Chinese herbs have been used to treat small-cell lung cancer (SCLC) due to their low toxicity and significant efficacy. This study focused on oridonin, a natural compound extracted from Rabdosia rubescens, and aimed to investigate its potential antitumor activity on SCLC and to evaluate the synergistic effect of combining oridonin with other small molecules. In this study, oridonin exhibited a dual effect. At lower concentrations, it suppressed the cell viability of SCLC cells (H1688 and H446). At high concentrations, oridonin induced SCLC cell apoptosis, damaged HBE cells in vitro and compromised the function of the liver and heart in vivo. The lower concentration of oridonin induced autophagy by enhancing the expression of p62 and the LC3B-II/LC3B-I ratio. This phenomenon might be associated with the activation of the protein kinase RNA-like ER kinase (PERK)/eukaryotic initiation factor 2 alpha (eIF2α)/growth arrest and DNA damage-inducible gene 153 (CHOP/GAD153) pathway. Therefore, the combined effect of oridonin with GSK2606414 or 3- methyladenine increased apoptosis in SCLC cells and reduced tumor growth. A similar phenomenon was observed after oridonin was combined with p62 or CHOP RNA interference treatment. Simultaneously, the combination of oridonin and GSK2606414 exhibited therapeutic efficacy without manifesting adverse effects. Our findings suggest that oridonin at lower concentrations can induce autophagy by activating the PERK/eIF2α/CHOP signaling pathway. The inhibition of the PERK/eIF2α/CHOP pathway could enhance oridonin therapeutic responses by triggering apoptosis. The novel therapeutic approach of combining oridonin with a PERK inhibitor is promising as a strategy for the treatment of SCLC.

The Natural Product Oridonin as an Anticancer Agent: Current Achievements and Problems

Oridonin, an active diterpenoid isolated from traditional Chinese herbal medicine, has received a rising attention for its remarkable roles in cancer therapy. In recent years, increasing evidences have revealed that oridonin inhibits the occurrence and development of tumor cells through multiple mechanisms, including induction of apoptosis and autophagy, cell cycle arrest, and inhibition of angiogenesis as well as migration and invasion. In addition, several molecular signal targets have been identified, including ROS, EGFR, NF-κB, PI3K/Akt, and MAPK. In this paper, we review considerable knowledge about the molecular mechanisms and signal targets of oridonin, which has been studied in recent years. It is expected that oridonin may be developed as a novel anti-tumor herbal medicine in human cancer treatment.

A review on the mechanisms underlying the antitumor effects of natural products by targeting the endoplasmic reticulum stress apoptosis pathway

Cancer poses a substantial risk to human life and wellbeing as a result of its elevated incidence and fatality rates. Endoplasmic reticulum stress (ERS) is an important pathway that regulates cellular homeostasis. When ERS is under- or overexpressed, it activates the protein kinase R (PKR)-like endoplasmic reticulum kinase (PERK)-, inositol-requiring enzyme 1 (IRE1)- and activating transcription Factor 6 (ATF6)-related apoptotic pathways to induce apoptosis. Tumor cells and microenvironment are susceptible to ERS, making the modulation of ERS a potential therapeutic approach for treating tumors. The use of natural products to treat tumors has substantially progressed, with various extracts demonstrating antitumor effects. Nevertheless, there are few reports on the effectiveness of natural products in inducing apoptosis by specifically targeting and regulating the ERS pathway. Further investigation and elaboration of its mechanism of action are still needed. This paper examines the antitumor mechanism of action by which natural products exert antitumor effects from the perspective of ERS regulation to provide a theoretical basis and new research directions for tumor therapy.

Oridonin promotes endoplasmic reticulum stress via TP53-repressed TCF4 transactivation in colorectal cancer

BACKGROUND

The incidence of colorectal cancer and cancer death rate are increasing every year, and the affected population is becoming younger. Traditional Chinese medicine therapy has a unique effect in prolonging survival time and improving the prognosis of patients with colorectal cancer. Oridonin has been reported to have anti-cancer effects in a variety of tumors, but the exact mechanism remains to be investigated.

METHODS

Cell Counting Kit-8 assay (CCK8) and 5-Ethynyl-2'-deoxyuridine (EdU) staining assay, Tranwell, and Wound healing assays were performed to measure cell proliferation, invasion, and migration capacities, respectively. The protein and mRNA expression levels of various molecules were reflected by Western blot and Reverse Transcription quantitative Polymerase Chain Reaction (qRT-PCR). Transcription Factor 4 (TCF4) and its target genes were analyzed by Position Weight Matrices (PWMs) software and the Gene Expression Omnibus (GEO) database. Immunofluorescence (IF) was performed to visualize the expression and position of Endoplasmic Reticulum (ER) stress biomarkers. The morphology of the ER was demonstrated by the ER tracker-red. Reactive Oxygen Species (ROS) levels were measured using a flow cytometer (FCM) or fluorescent staining. Calcium ion (Ca²⁺) concentration was quantified by Fluo-3 AM staining. Athymic nude mice were modeled with subcutaneous xenografts.

RESULTS

Oridonin inhibited the proliferation, invasion, and migration of colorectal cancer, and this effect was weakened in a concentration-dependent manner by ER stress inhibitors. In addition, oridonin-induced colorectal tumor cells showed increased expression of ER stress biomarkers, loose morphology of ER, increased vesicles, and irregular shape. TCF4 was identified as a regulator of ER stress by PWMs software and GEO survival analysis. In vitro and in vivo experiments confirmed that TCF4 inhibited ER stress, reduced ROS production, and maintained Ca²⁺ homeostasis. In addition, oridonin also activated TP53 and inhibited TCF4 transactivation, further exacerbating the elevated ROS levels and calcium ion release in tumor cells and inhibiting tumorigenesis in colorectal cancer cells in vivo.

CONCLUSIONS

Oridonin upregulated TP53, inhibited TCF4 transactivation, and induced ER stress dysregulation in tumor cells, promoting colorectal cancer cell death. Therefore, TCF4 may be one of the important nodes for tumor cells to regulate ER stress and maintain protein synthesis homeostasis. And the inhibition of the TP53/TCF4 axis plays a key role in the anti-cancer effects of oridonin.

Up-regulated oxidized USP2a can increase Mdm2-p60-p53 to promote cell apoptosis

Mdm2 promotes the ubiquitination and degradation of p53, while Mdm2-p60 can bind to p53 and reduce the Mdm2-induced p53 ubiquitination to improve its stability. USP2a can deubiquitinate and stabilize Mdm2, whether USP2a can regulate Mdm2-p60 needs to be further confirmed and elucidated. We found that oxidative stress can up-regulate USP2a at the post-transcriptional level and induce USP2a to be oxidized by forming inter-subunit disulfide bonds. The oxidized USP2a is closely related with cell apoptosis. In apoptotic cells, oxidized USP2a has enhanced protein stability and further stabilizes Mdm2-p60 through deubiquitination, and the USP2a-Mdm2-p60-p53 axis plays a role in cell apoptosis. Altogether USP2a is oxygen sensitive, oxidized USP2a exerts apoptotic effects through the Mdm2-p60-p53 axis, which provides an experimental basis for regulating p53 apoptotic signaling by targeting USP2a.

Comprehensive analysis reveals COPB2 and RYK associated with tumor stages of larynx squamous cell carcinoma

BACKGROUND

Laryngeal squamous cell carcinoma (LSCC) is one of the highly aggressive malignancy types of head and neck squamous cell carcinomas; genes involved in the development of LSCC still need exploration.

METHODS

We downloaded expression profiles of 96 (85 in advanced stage and 11 in early stage) LSCC patients from TCGA-HNSC. Function enrichment and protein-protein interactions of genes in significant modules were conducted. Univariate and multivariate Cox regression analyses were performed to explore potential prognostic biomarkers for LSCC. The expression levels of genes at different stages were compared and visualized via boxplots. Immune infiltration was examined by the CIBERSORTx web-based tool and depicted with ggplot2. Gene set enrichment analysis (GSEA) was utilized to analyze functional enrichment terms and pathways. Immunohistochemical staining (IHC) was used to verify the expression of genes in the LSCC samples.

RESULTS

We identified 25 modules, including 3 modules significantly related to tumor stages of LSCC via weighted gene co-expression network analysis (WGCNA). UIMC1, NPM1, and DCTN4 in the module 'cyan', TARS in the module 'darkorange', and COPB2 and RYK in the module 'lightyellow' showed statistically significant relation to overall survival. The expression of COPB2, DCTN4, RYK, TARS, and UIMC1 indicated association with the change of fraction of immune cells in LSCC patients; two genes, COPB2 and RYK, indicated different expression in various tumor stages of LSCC. Finally, COPB2 and RYK showed high-expression in tumor tissues of advanced LSCC patients.

CONCLUSIONS

Our study provided a potential perceptive in analyzing progression of LSCC cells and exploring prognostic genes.

Nucleus Near-Infrared (nNIR) Irradiation of Single A549 Cells Induces DNA Damage and Activates EGFR Leading to Mitochondrial Fission

There has been great interest in identifying the biological substrate for light-cell interaction and their relations to cancer treatment. In this study, a near-infrared (NIR) laser is focused into the nucleus (nNIR) or cytoplasm (cNIR) of a single living cell by a high numerical aperture condenser to dissect the novel role of cell nucleus in mediating NIR effects on mitochondrial dynamics of A549 non-small cell lung cancer cells. Our analysis showed that nNIR, but not cNIR, triggered mitochondrial fission in 10 min. In contrast, the fission/fusion balance of mitochondria directly exposed to cNIR does not change. While the same phenomenon is also triggered by single molecular interactions between epidermal growth factor (EGF) and its receptor EGFR, pharmacological studies with cetuximab, PD153035, and caffeine suggest EGF signaling crosstalk to DNA damaging response to mediate rapid mitochondrial fission as a result of nNIR irradiation. These results suggest that nuclear DNA integrity is a novel biological target for cellular response to NIR.

Pharmacokinetics Study of Rabdosia Rubescens Drop Pills Based on UPLC-MS/MS

Background:

Rabdosia rubescens drop pills have the effects of clearing away heat and toxin, detumescence, relieving pain.

Objective:

A simple and sensitive method for simultaneous determination of oridonin, ponicidin, and rosmarinic acid in rat plasma was developed based on ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).

Methods:

Chromatographic separation was performed on a Waters ACQUITY UPLC BEH C18 column (2.1 × 100 mm, 1.7 µm) with a mobile phase consisting of water containing 0.2% formic acid (mobile phase A) and methanol (mobile phase B) at a flow rate of 0.3 mL/min over a total run time of 3.8 min. All analytes were measured with optimized multiple reaction monitoring (MRM) in positive and negative ion ESI mode.

Results:

The transitions of oridonin, ponicidin, rosmarinic acid, diphenhydramine, and chloramphenicol were 365.3→347.3, 363.3→345.2, 359.0→160.9, 256.0→167.2, and 321.1→151.9, respectively. The linear ranges were 1-256 ng/mL for ponicidin and rosmarinic acid and 2-512 ng/mL for oridonin. The validated method wasstable and reliable. There was no significant difference in the half-life (t1/2) of the three analytes at three doses. The area under the curve (AUC0-t) and peak concentration (Cmax) of the three analytes decreased linearly in each dose range, and the linear correlation R2 of each analyte under the three doses was greater than 0.95.

Conclusion:

This method was successfully applied to pharmacokinetic studies of oridonin, ponicidin, and rosmarinic acid in rat plasma after intragastric administration of Rabdosia rubescens drop pills.

Multiple targeted self-emulsifying compound RGO reveals obvious anti-tumor potential in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a highly vascularized, inflammatory, and abnormally proliferating tumor. Monotherapy is often unable to effectively and comprehensively inhibit the progress of HCC. In present study, we selected ginsenoside Rg3, ganoderma lucidum polysaccharide (GLP), and oridonin as the combined therapy. These three plant monomers play important roles in anti-angiogenesis, immunological activation, and apoptosis promotion, respectively. However, the low solubility and poor bioavailability seriously hinder their clinical application. To resolve these problems, we constructed a new drug, Rg3, GLP, and oridonin self-microemulsifying drug delivery system (RGO-SMEDDS). We found that this drug effectively inhibits the progression of HCC by simultaneously targeting multiple signaling pathways. RGO-SMEDDS restored immune function by suppressing the production of immunosuppressive cytokine and M2-polarized macrophages, reduced angiogenesis by downregulation of vascular endothelial growth factor and its receptor, and retarded proliferation by inhibiting the epidermal growth factor receptor EGFR/AKT/epidermal growth factor receptor/protein kinase B/glycogen synthase kinase-3 (GSK3) signaling pathway. In addition, RGO-SMEDDS showed considerable safety in acute toxicity tests. Results from this study show that RGO-SMEDDS is a promising therapy for the treatment of HCC.

Oridonin: A Review of Its Pharmacology, Pharmacokinetics and Toxicity

Oridonin, as a natural terpenoids found in traditional Chinese herbal medicine Isodon rubescens (Hemsl.) H.Hara, is widely present in numerous Chinese medicine preparations. The purpose of this review focuses on providing the latest and comprehensive information on the pharmacology, pharmacokinetics and toxicity of oridonin, to excavate the therapeutic potential and explore promising ways to balance toxicity and efficacy of this natural compound. Information concerning oridonin was systematically collected from the authoritative internet database of PubMed, Elsevier, Web of Science, Wiley Online Library and Europe PMC applying a combination of keywords involving "pharmacology," "pharmacokinetics," and "toxicology". New evidence shows that oridonin possesses a wide range of pharmacological properties, including anticancer, anti-inflammatory, hepatorenal activities as well as cardioprotective protective activities and so on. Although significant advancement has been witnessed in this field, some basic and intricate issues still exist such as the specific mechanism of oridonin against related diseases not being clear. Moreover, several lines of evidence indicated that oridonin may exhibit adverse effects, even toxicity under specific circumstances, which sparked intense debate and concern about security of oridonin. Based on the current progress, future research directions should emphasize on 1) investigating the interrelationship between concentration and pharmacological effects as well as toxicity, 2) reducing pharmacological toxicity, and 3) modifying the structure of oridonin-one of the pivotal approaches to strengthen pharmacological activity and bioavailability. We hope that this review can provide some inspiration for the research of oridonin in the future.

Mitochondrial Dynamics, ROS, and Cell Signaling: A Blended Overview

Mitochondria are key intracellular organelles involved not only in the metabolic state of the cell, but also in several cellular functions, such as proliferation, Calcium signaling, and lipid trafficking. Indeed, these organelles are characterized by continuous events of fission and fusion which contribute to the dynamic plasticity of their network, also strongly influenced by mitochondrial contacts with other subcellular organelles. Nevertheless, mitochondria release a major amount of reactive oxygen species (ROS) inside eukaryotic cells, which are reported to mediate a plethora of both physiological and pathological cellular functions, such as growth and proliferation, regulation of autophagy, apoptosis, and metastasis. Therefore, targeting mitochondrial ROS could be a promising strategy to overcome and hinder the development of diseases such as cancer, where malignant cells, possessing a higher amount of ROS with respect to healthy ones, could be specifically targeted by therapeutic treatments. In this review, we collected the ultimate findings on the blended interplay among mitochondrial shaping, mitochondrial ROS, and several signaling pathways, in order to contribute to the dissection of intracellular molecular mechanisms involved in the pathophysiology of eukaryotic cells, possibly improving future therapeutic approaches.

Behind the Scenes: Nod-Like Receptor X1 Controls Inflammation and Metabolism

Regulatory Nod-like receptors (NLRs) are a subgroup of the cytosolic NLR family of pathogen recognition receptors (PRRs). These receptors can tune the innate immune responses triggered by the activation of other PRRs by either augmenting or attenuating the activated pro-inflammatory signaling cascades. Nod-like receptor X1 (NLRX1) is the only known mitochondria-associated negative regulatory NLR. NLRX1 attenuates several inflammatory pathways and modulates cellular processes such as autophagy and mitochondrial function following infection or injury. Using both in vitro expression and in vivo experimental models, NLRX1 is extensively described in the context of anti-viral signaling and host-defense against invading pathogens. More recently, NLRX1 has also gained interest in the field of cancer and metabolism where NLRX1 functions to attenuate overzealous inflammation in various inflammatory and autoimmune diseases. However, the exact function of this novel receptor is still under debate and many, often contradictory, mechanisms of action together with cellular localizations have been proposed. Thus, a better understanding of the underlying mechanism is crucial for future research and development of novel therapeutical approaches. Here, we summarize the current findings on NLRX1 and discuss its role in both infectious and inflammatory context.