Paeonol-mediated apoptosis of hepatocellular carcinoma cells by NF-κB pathway

Silencing of TRAF5 enhances necroptosis in hepatocellular carcinoma by inhibiting LTBR-mediated NF-κB signaling

Background

Hepatocellular carcinoma (HCC) is a common malignancy with poor prognosis and high mortality. This study aimed to explore the oncogenic mechanisms of TRAF5 in HCC and provide a novel therapeutic strategy for HCC.

Methods

Human HCC cell lines (HepG2, HuH7, SMMC-LM3, and Hep3B), normal adult liver epithelial cells (THLE-2), and human embryonic kidney cells (HEK293T) were utilized. Cell transfection was performed for functional investigation. qRT-PCR and western blotting were used to detect mRNA expression of TRAF5, LTBR, and NF-κB and protein expression of TRAF5, p-RIP1(S166)/RIP1, p-MLKL(S345)/MLKL, LTBR, and p-NF-κB/NF-κB. Cell viability, proliferation, migration, and invasion were evaluated using CCK-8, colony formation, wound healing, and Transwell assays. Cell survival, necrosis, and apoptosis were assessed using flow cytometry and Hoechst 33342/PI double staining. Co-immunoprecipitation and immunofluorescence were performed to determine the interaction between TRAF5 and LTBR. A xenograft model was established to validate the role of TRAF5 in HCC.

Results

TRAF5 knockdown inhibited HCC cell viability, colony formation, migration, invasion, and survival but enhanced necroptosis. Additionally, TRAF5 is correlated with LTBR and TRAF5 silencing down-regulated LTBR in HCC cells. LTBR knockdown inhibited HCC cell viability, while LTBR overexpression eliminated the effects of TRAF5 deficiency on inhibiting HCC cell proliferation, migration, invasion, and survival. LTBR overexpression abolished the promotive function of TRAF5 knockdown on cell necroptosis. LTBR overexpression undid the suppressive effect of TRAF5 knockdown on NF-κB signaling in HCC cells. Moreover, TRAF5 knockdown suppressed xenograft tumor growth, inhibited cell proliferation, and promoted tumor cell apoptosis.

Conclusions

TRAF5 deficiency facilitates necroptosis in HCC by suppressing LTBR-mediated NF-κB signaling.

Pharmacological effects and mechanisms of paeonol on antitumor and prevention of side effects of cancer therapy

Cancer represents one of the leading causes of mortality worldwide. Conventional clinical treatments include radiation therapy, chemotherapy, immunotherapy, and targeted therapy. However, these treatments have inherent limitations, such as multidrug resistance and the induction of short- and long-term multiple organ damage, ultimately leading to a significant decrease in cancer survivors' quality of life and life expectancy. Paeonol, a nature active compound derived from the root bark of the medicinal plant Paeonia suffruticosa, exhibits various pharmacological activities. Extensive research has demonstrated that paeonol exhibits substantial anticancer effects in various cancer, both in vitro and in vivo. Its underlying mechanisms involve the induction of apoptosis, the inhibition of cell proliferation, invasion and migration, angiogenesis, cell cycle arrest, autophagy, regulating tumor immunity and enhanced radiosensitivity, as well as the modulation of multiple signaling pathways, such as the PI3K/AKT and NF-κB signaling pathways. Additionally, paeonol can prevent adverse effects on the heart, liver, and kidneys induced by anticancer therapy. Despite numerous studies exploring paeonol's therapeutic potential in cancer, no specific reviews have been conducted. Therefore, this review provides a systematic summary and analysis of paeonol's anticancer effects, prevention of side effects, and the underlying mechanisms involved. This review aims to establish a theoretical basis for the adjunctive strategy of paeonol in cancer treatment, ultimately improving the survival rate and enhancing the quality of life for cancer patients.

Paeonol Protects Against Methotrexate-Induced Nephrotoxicity via Upregulation of P-gp Expression and Inhibition of TLR4/NF-κB Pathway

Methotrexate (MTX) is a well-known anticancer drug that causes nephrotoxicity as a side effect. To investigate the mechanisms by which paeonol, a natural phenolic compound, can protect against MTX-induced nephrotoxicity, paeonol (100 mg/kg/day orally) was given to rats for 10 days, with or without MTX (20 mg/kg once i.p. at day 5). Compared to control, MTX caused nephrotoxic effects manifested by increased serum urea and creatinine and distortion in renal histological architecture, with a significant increase in the mean glomerular diameter and upregulation of kidney injury molecule-1. MTX caused oxidative stress manifested by decreasing reduced glutathione and superoxide dismutase while increasing malondialdehyde and nitric oxide. MTX also induced renal inflammation by upregulating TLR4, NF-κB, and IL-1β and caused apoptosis by induction of caspase 3. Administering paeonol with MTX improved kidney functional and structural parameters, as well as all oxidative, inflammatory, and apoptotic markers tested. Interestingly, both MTX and paeonol increased the expression of the renal efflux transporter P-glycoprotein (P-gp) that helps in MTX elimination, and their drug combination further upregulated renal P-gp. In silico, paeonol was neither a substrate nor an inhibitor of P-gp, suggesting that its effect on P-gp is not on functional but on the expression level. In vitro, paeonol and MTX were administered to colon cancer cells and their combination caused a progressive cellular cytotoxic effect, which was dose-dependent with the increase of paeonol concentration. In conclusion, paeonol protects against MTX-induced nephrotoxicity through antioxidant, anti-inflammatory, and antiapoptotic mechanisms and might potentiate MTX chemotherapeutic efficacy.

Paeonol induces antitumor effects in hepatocellular carcinoma cells through survivin via the cyclooxygenase-2/prostaglandin E2 signaling pathway

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most life-threatening malignancies worldwide due to the lack of significant improvement in therapeutic methods. This study aimed to unravel the effects of paeonol, the main active component of Paeonia suffruticosa, on survivin, a key molecule in tumorigenesis, and elucidate the mechanisms by which paeonol exerts antineoplastic effects in human HCC cells.

METHODS

Immunohistochemistry (IHC) was used to study the expression levels of survivin and cyclooxygenase-2 (COX-2) in 57 human HCC tissue samples. Human HCC cell lines (HepG2 and SMMC-7721) were treated with prostaglandin E2 (PGE2). Subsequently, the cells were treated with paeonol and NS-398, and the expression levels of survivin, COX-2, and PGE2 were evaluated by Western blotting and enzyme-linked immunosorbent assay (ELISA), respectively. Fluorescence-activated cell sorting (FACS) and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining were performed to analyze cell proliferation and apoptosis.

RESULTS

Survivin was expressed in 47 of 57 human HCC tissue samples, as observed by IHC, and its expression was correlated with COX-2 activity. Furthermore, Western blotting showed that the expression of survivin was increased in HepG2 and SMMC-7721 cells treated with PGE2, the biosynthesis of which is mainly regulated by COX-2. Interestingly, FACS and TUNEL staining demonstrated that paeonol significantly inhibited the proliferation of HepG2 and SMMC-7721 cells and induced apoptosis, concomitant with the downregulation of survivin. The levels of COX-2 and PGE2 were also reduced by paeonol, as confirmed by Western blotting and ELISA, respectively. To determine the mechanism by which paeonol inhibited survivin in HCC cells the effects of COX-2 expression on surviving were studied. Treatment with the COX-2 selective inhibitor NS398 effectively decreased the levels of PGE2 and survivin, inducing apoptosis in a manner similar to that of paeonol. Survivin expression was increased by PGE2 treatment but was blocked by paeonol, which suggests that paeonol inhibits survivin by inhibiting the COX-2/PGE2 signaling pathway.

CONCLUSIONS

To the best of our knowledge, this is the first study to demonstrate that paeonol can exert antitumor effects on HCC cells by targeting survivin via the COX-2/PGE2 signaling pathway. Paeonol could therefore be considered as a potential therapeutic candidate for HCC.

Paeonol exerts anti‑tumor activity against colorectal cancer cells by inducing G0/G1 phase arrest and cell apoptosis via inhibiting the Wnt/β‑catenin signaling pathway

Paeonol is a simple phenolic compound isolated from herbal root bark, which has been reported to possess numerous biological and pharmacological characteristics, including a desirable anti‑tumor effect. To date, the effect of paeonol against colorectal cancer (CRC) cells is yet to be fully elucidated. Therefore, the present study aimed to identify the underlying mechanism via which paeonol exerts its anti‑tumor activity on HCT116 cells. After incubation with various concentrations of paeonol (7.8125, 15.625, 31.25, 62.5, 125, 250 and 500 µg/ml), the inhibitory effect of paeonol on cell viability was assessed using a Cell Counting Kit‑8 assay. Cell apoptosis and cell cycle distribution were measured using flow cytometry. Moreover, caspase activity was measured using a colorimetric caspase assay. Luciferase assay was also used to determine the β‑catenin‑mediated transcriptional activity of T‑cell specific transcription factor/lymphoid‑enhancer binding factor (TCF/LEF), and western blotting analysis was performed to measure the related expression of proteins. The results indicated that paeonol exhibited a notable effect against HCT116 cells by inducing G0/G1‑phase arrest, as demonstrated by downregulation of the cell cycle regulators cyclin‑dependent kinase 4 and cyclin D1 and upregulation of p21Cip1 in a dose‑dependent manner. Furthermore, paeonol dose‑dependently induced cell apoptosis, accompanied by an increase in the Bax/Bcl‑2 ratio, release of cytochrome c and further activation of caspases. Paeonol also dose‑dependently blocked the activation of the Wnt/β‑catenin signaling pathway by suppressing the expression of β‑catenin, resulting in a decrease in β‑catenin‑mediated activity of TCF/LEF and downregulation of downstream target genes, including cyclin D1, survivin and c‑Myc. Therefore, the present results suggested that paeonol exerted its anti‑tumor effects on CRC cells, including the inhibition of cell proliferation, induction of cell cycle arrest and initiation of apoptosis, at least partly by suppressing the Wnt/β‑catenin pathway, which may offer a promising therapeutic strategy for CRC.

Paeonol Attenuates Methotrexate-Induced Cardiac Toxicity in Rats by Inhibiting Oxidative Stress and Suppressing TLR4-Induced NF-κB Inflammatory Pathway

Methotrexate (MTX) is a commonly used chemotherapeutic agent. Oxidative stress and inflammation have been proved in the development of MTX toxicity. Paeonol is a natural phenolic compound with various pharmacological activities including antioxidant and anti-inflammatory properties. The aim of the present study was to evaluate the protective effect of paeonol against MTX-induced cardiac toxicity in rats and to evaluate the various mechanisms that underlie this effect. Paeonol (100 mg/kg) was administered orally for 10 days. MTX cardiac toxicity was induced at the end of the fifth day of the experiment, with or without paeonol pretreatment. MTX-induced cardiac damage is evidenced by a distortion in the normal cardiac histological structure, with significant oxidative and nitrosative stress shown as a significant increase in NADPH oxidase-2, malondialdehyde, and nitric oxide levels along with a decrease in reduced glutathione concentration and superoxide dismutase activity compared to the control group. MTX-induced inflammatory effects are evidenced by the increased cardiac toll-like receptor 4 (TLR4) mRNA expression and protein level as well as increased cardiac tumor necrosis factor- (TNF-) α and interleukin- (IL-) 6 levels along with increased nuclear factor- (NF-) κB/p65 immunostaining. MTX increased apoptosis as shown by the upregulation of cardiac caspase 3 immunostaining. Paeonol was able to correct the oxidative and nitrosative stress as well as the inflammatory and apoptotic parameters and restore the normal histological structure compared to MTX alone. In conclusion, paeonol has a protective effect against MTX-induced cardiac toxicity through inhibiting oxidative and nitrosative stress and suppressing the TLR4/NF-κB/TNF-α/IL-6 inflammatory pathway, as well as causing an associated reduction in the proapoptotic marker, caspase 3.

Benzophenones from Anemarrhena asphodeloides Bge. Exhibit Anticancer Activity in HepG2 Cells via the NF-κB Signaling Pathway

A chemical investigation of the fibrous roots of Anemarrhena asphodeloides Bge. led to the isolation of four benzophenones, including one new compound (1) and three known ones (2–4). Comprehensive ¹D, ²D NMR and HRESIMS data established the structures of the isolated compounds. The absolute configurations were determined by comparison of the calculated optical rotation (OR) with experimental data. All the isolates were evaluated for their cytotoxicities on hepatocellular carcinoma cell lines (HepG2 and Hep3B). Compound 1 showed strong cytotoxicity against HepG2 and Hep3B cells, with IC₅₀ values at 153.1 and 180.6 nM. Through MTT assay, flow cytometry and Western blot analysis, compound 1 demonstrated the ability to stimulate apoptosis via the NF-κB signaling pathway in HepG2 cells. These benzophenones are potential lead compounds for the development of better treatments for hepatocellular carcinoma.