Pentoxifylline induces apoptosis of HepG2 cells by reducing reactive oxygen species production and activating the MAPK signaling

Chemosensitizing effect of pentoxifylline in sensitive and multidrug-resistant non-small cell lung cancer cells

Aim: Multidrug resistance (MDR) is frequent in non-small cell lung cancer (NSCLC) patients, which can be due to its fibrotic stroma. This work explores the combination of pentoxifylline, an anti-fibrotic and chitinase 3-like-1 (CHI3L1) inhibitor drug, with conventional chemotherapy to improve NSCLC treatment. Methods: The effect of pentoxifylline in the expression levels of P-glycoprotein (P-gp), CHI3L1 and its main downstream proteins, as well as on cell death, cell cycle profile, and P-gp activity was studied in two pairs of sensitive and MDR counterpart NSCLC cell lines (NCI-H460/NCI-H460/R and A549/A549-CDR2). Association studies between CHI3L1 gene expression and NSCLC patients' survival were performed using The Cancer Genome Atlas (TCGA) analysis. The sensitizing effect of pentoxifylline to different drug regimens was evaluated in both sensitive and MDR NSCLC cell lines. The cytotoxicity of the drug combinations was assessed in MCF10A non-tumorigenic cells. Results: Pentoxifylline slightly decreased the expression levels of CHI3L1, β-catenin and signal transducer and activator of transcription 3 (STAT3), and caused a significant increase in the G1 phase of the cell cycle in both pairs of NSCLC cell lines. A significant increase in the % of cell death was observed in the sensitive NCI-H460 cell line. TCGA analysis revealed that high levels of CHI3L1 are associated with low overall survival (OS) in NSCLC patients treated with vinorelbine. Moreover, pentoxifylline sensitized both pairs of sensitive and MDR NSCLC cell lines to the different drug regimens, without causing significant toxicity to non-tumorigenic cells. Conclusion: This study suggests the possibility of combining pentoxifylline with chemotherapy to increase NSCLC therapeutic response, even in cases of MDR.

Pentoxifylline changes the balance of immune cell population in breast tumor-infiltrating lymphocytes

Immunotherapy utilizing tumor-infiltrating lymphocytes (TILs) is a promising approach for cancer treatment. Pentoxifylline (PTXF), a xanthine derivative, exhibits antitumor properties. This study aimed to investigate the impact of PTXF on the phenotype and function of TILs and splenocytes in a triple-negative breast cancer (TNBC) mouse model. TNBC was subcutaneously induced in BALB/c mice, followed by nine intraperitoneal injections of 100 mg/kg PTXF. TILs were then isolated by enzymatic digestion of tumors and cocultured with 4T1 cells. The proportion of regulatory T cells (Tregs) and cytotoxic T cells in TILs and splenocytes was assessed using flow cytometry. Transforming growth factor (TGF)-β and interferon (IFN)-γ production in TILs and splenocytes cultures was measured by ELISA. Relative expression of t-bet, foxp3, gata-3, and ror-γt in TILs and splenocytes was evaluated using real-time PCR. Tumor growth in PTXF-treated mice was significantly lower than that in the controls (P < 0.01). The frequency of regulatory and cytotoxic TILs in PTXF-treated mice was approximately half (P < 0.01) and twice (P < 0.05) that of the control group, respectively. The level of TGF-β and IFN-γ in the supernatant of PTXF-treated TILs was decreased and increased, respectively (P < 0.05). The relative expression of t-bet and foxp3 in the PTXF-treated mice compared to controls was increased and decreased, respectively (P < 0.05). Changes in the immune cell balance were less significant in the spleen compared to the TILs. PTXF treatment could limit the tumor growth and modify the regulatory-to-cytotoxic TILs ratio, as well as cytokine balance of TILs, in favor of antitumor responses.

Retinoblastoma: Review and new insights

Retinoblastoma (Rb), the most frequent malignant intraocular tumor in childhood, is caused by mutations in the retinoblastoma gene (RB1) situated on chromosome 13q14.2. The incidence of retinoblastoma is approximately 1 in 17,000 live births with approximately 8,000 new cases diagnosed each year worldwide. Rb is the prototypical hereditary cancer in humans. Autosomal dominant inheritance is seen in 30-40% of cases whereas the non-inherited sporadic type accounts for the remaining 60-70%. Rb arises due to inactivation of both alleles of the Rb tumor suppressor gene, which results in a defective Rb protein (pRB) with subsequent cell cycle impairment and uncontrolled cell proliferation. Patients with Rb have survival rates higher than 95-98% in industrialized countries but mortality remains high in developing countries. For example, the mortality rate in Africa is 70%. In all cases of intraocular and extraocular retinoblastoma, there is a need for new therapies that are more effective and carry less risk of toxicity. The Bruckner test is a practical and easy test for the detection of Rb, this test consists of assessing the fundus reflex through the pupil (red reflex) in both eyes simultaneously with a bright coaxial light produced with the direct ophthalmoscope. Rb can be detected by the Bruckner test showing a pupil that shines white or “Leukocoria”. Although the diagnosis of Rb remains essentially clinical, the newly identified biomarkers could contribute to early molecular detection, timely detection of micrometastases and establish new therapeutic options for Rb.

Isobavachalcone disrupts mitochondrial respiration and induces cytotoxicity through ROS accumulation and Akt suppression

Isobavachalcone (IBC) is one of the flavonoid components in Fructus Psoraleae, and has been found multiple pharmacological effects. However, the hepatotoxicity of IBC has been overlooked and not been carefully studied. We aim to find out the cytotoxicity of IBC on HepG2 cells, and explore the underlying mechanisms. HepG2 cells were treated with IBC for 24 h, then MTT assay and LDH assay were used to detect the cell viability. The apoptosis and reactive oxygen species (ROS) production were reflected by the flow cytometry. Using Seahorse Analyzer, we measured the mitochondrial respiratory capacity. The expression of oxidative stress and mitochondrial apoptosis-related proteins were determined by Western blot. The results showed that IBC induced the cell death and apoptosis of HepG2 cells. IBC initiated the accumulation of ROS in cells and impaired the mitochondrial function, triggered apoptosis and suppressed the phosphorylation of Akt. Additionally, scavenging ROS by the antioxidant N-acetyl-l-cysteine (NAC) reduced IBC-induced mitochondria damage and increased Akt phosphorylation. Taken together, IBC caused mitochondrial damage and induced hepatotoxicity by ROS accumulation and Akt suppression. Targeting oxidative stress and depressing mitochondrial damage may provide a theoretical basis for the treatment and prevention of IBC-induced hepatotoxicity in clinic.

A Novel Peptide Isolated from Microalgae Isochrysis zhanjiangensis Exhibits Anti-apoptosis and Anti-inflammation in Ox-LDL Induced HUVEC to Improve Atherosclerosis

In the early stage, oxidized low density lipoprotein (ox-LDL) caused atherosclerosis, followed by human umbilical vein endothelial cells (HUVEC) damage, leading to a variety of cardiovascular related diseases. This study investigated the mechanism of nonapeptide (EMFGTSSET, ETT) isolated from in vitro gastrointestinal digestion of Isochrysis zhanjiang on endothelial cell inflammation and apoptosis induced by ox-LDL in atherosclerosis. At the cellular level, the results shown that ETT inhibited the up-regulation of oxidized low-density lipoprotein receptor-1 (LOX-1) induced by ox-LDL. Furthermore, ETT inhibited the fluorescence intensity of ROS, inflammatory factors (interleukin-6, interleukin-1β, and tumor necrosis factor-α) and the expression of cell adhesion molecules (vascular cell adhesion protein 1 and intercellular cell adhesion molecule-1). In addition, it also upregulates nuclear red blood cell 2 related factor 2 (Nrf2), heme oxygenase-1 (HO -1), p-Akt, and bcl-2 levels. But down-regulated the expression of p-p65, p-IκB-α, p-p38, p-ERK, p-JNK, bax, and cleaved caspase-9/-3 (c-c-9/-3), thereby inhibited ox-LDL induction inflammation and apoptosis of atherosclerosis. Through molecular docking, it was judged that the stable interaction between ETT and LOX-1 and VCAM-1 was maintained through hydrogen bonding. These results can provide a theoretical basis for ETT as a potential substance for the prevention and treatment of atherosclerosis, and further improve the value of Isochrysis zhanjiangensis.

Lappaconitine hydrochloride inhibits proliferation and induces apoptosis in human colon cancer HCT-116 cells via mitochondrial and MAPK pathway

Lappaconitine hydrochloride (LH), as a new synthetic alkaloid, exhibits antitumor activity, whereas its antitumor effect on colorectal cancer (CRC) has not been investigated. In this study, the effect of LH on HCT-116 cell proliferation and apoptosis in vivo and in vitro and underlying molecular mechanism were explored. The Cell Counting Kit-8 (CCK-8) was used to assess cell viability. Morphological change was observed by Hoechst 33342 staining. Cell cycle and apoptosis were performed using a flow cytometer. The western blot method was used to screen for related protein expression. The mitochondrial membrane potential (MMP) was confirmed using the 5, 5, 6, 6'-tetrachloro-1, 1', 3, 3'-tetraethylbenzimi-dazolyl carbo cyanine iodide (JC-1) staining assay. Reactive oxygen species (ROS) was evaluated by a 20-70-dichlorofluorescein diacetate (DCFH-DA) staining assay. The antitumor effect was evaluated in vivo by the xenograft HCT-116 model. The results showed that LH significantly inhibited cell viability in a time- and concentration-dependent manner. LH induced apoptosis and S phase cell cycle arrest. LH promoted the reduction of MMP and ROS accumulation. Moreover, LH activated the mitochondrial and MAPK pathway. The experiments in vivo showed that LH had significant antitumor effect in tumor-bearing mice, and had virtually no effect on the weight and internal organs of the mice. In conclusion, LH could induce apoptosis in HCT-116 cells through mitochondrial and MAPK signaling pathways. LH may be a promising treatment for CRC.

Intracellular ethanol-mediated oxidation and apoptosis in HepG2/CYP2E1 cells impaired by two active peptides from seahorse (Hippocampus kuda bleeler) protein hydrolysates via the Nrf2/HO-1 and akt pathways

Seahorse (Hippocampus kuda Bleeler) are representative marine species in aquaculture, with special value of medicine and food. In this study, the protective effects of two peptides from seahorse hydrolysates (SHP-1 and SHP-2) against ethanol-mediated oxidative stress in HepG2/CYP2E1 cells were investigated. Firstly, SHP-1 and SHP-2 presented no cytotoxicity. Compared with the ethanol-treated groups, SHP-1 and SHP-2 increased cell viability in a concentration-dependent manner. Secondly, SHP-1 and SHP-2 markedly reduced intracellular reactive oxygen species (ROS) generation, gamma-glutamyltranspeptidase (GGT) activity, and tumor necrosis factor-α (TNF-α) levels and remarkably enhanced superoxide dismutase (SOD) and glutathione (GSH) activities. SHP-1 and SHP-2 also down-regulated the expressions of GGT, bax, c-caspase-8/-9/-3, p-Akt, p-IκB-α, p-p65, p-ERK, and p-p38 but up-regulated SOD, GSH, NF-E2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and bcl-2 levels, as revealed by Western blot analysis. Moreover, SHP-1 and SHP-2 increased the mitochondrial membrane potential (MMP), reduced DNA damage, and suppressed the nuclear translocation of p65. These results suggest that two peptides from seahorse hydrolysates can be considered a potential functional biomaterial and further improve the use value of seahorse in aquaculture.

Pentoxifylline Enhances the Apoptotic Effect of Carboplatin in Y79 Retinoblastoma Cells

BACKGROUND/AIM

Retinoblastoma (RB) is the most common primary intraocular malignancy. Carboplatin (CPt) is a DNA damage-inducing agent that is widely used for the treatment of RB. Unfortunately, this drug also activates the transcription factor nuclear factor-kappa B (NF-ĸB), leading to promotion of tumor survival. Pentoxifylline (PTX) is a drug that inhibits the phosphorylation of I kappa B-alpha (IĸBα) in serines 32 and 36, and this disrupts NF-ĸB activity that promotes tumor survival. The goal of this study was to evaluate the effect of the PTX on the antitumor activity of CPt.

MATERIALS AND METHODS

Y79 RB cells were treated with CPt, PTX, or both. Cell viability, apoptosis, loss of mitochondrial membrane potential, the activity of caspase-9, -8, and -3, cytochrome c release, cell-cycle progression, p53, and phosphorylation of IĸBα, and pro- and anti-apoptotic genes were evaluated.

RESULTS

Both drugs significantly affected the viability of the Y79 RB cells in a time- and dose-dependent manner. The PTX+CPt combination exhibited the highest rate of apoptosis, a decrease in cell viability and significant caspase activation, as well as loss of mitochondrial membrane potential, release of cytochrome c, and increased p53 protein levels. Cells treated with PTX alone displayed decreased I kappa B-alpha phosphorylation, compared to the CPt treated group. In addition, the PTX+CPt combination treatment induced up-regulation of the proapoptotic genes Bax, Bad, Bak, and caspases- 3, -8, and -9, compared to the CPt and PTX individual treated groups.

CONCLUSION

PTX induces apoptosis per se and increases the CPt-induced apoptosis, augmenting its antitumor effectiveness.

The therapeutic effects of nicotinamide in hepatocellular carcinoma through blocking IGF-1 and effecting the balance between Nrf2 and PKB

Insulin growth factor (IGF) family and their receptors play a great role in tumors' development. In addition, IGF-1 enhances cancer progression through regulating cell proliferation, angiogenesis, immune modulation and metastasis. Moreover, nicotinamide is association with protection against cancer. Therefore, we conducted this research to examine the therapeutic effects of nicotinamide against hepatocellular carcinoma (HCC) both in vivo and in vitro through affecting IGF-1 and the balance between PKB and Nrf2. HCC was induced in rats by 200 mg/kg, ip thioacetamide. The rat survival, number and size of tumors and serum α-fetoprotein (AFP) were measured. The gene and protein levels of IGF-1, Nrf2, PKB and JNK-MAPK were assessed in rat livers. In addition, HepG2 cells, human HCC cell lines, were treated with different concentrations of nicotinamide. We found that nicotinamide enhanced the rats' survival and reduced the number and size of hepatic tumors as well as it reduced serum AFP and HepG2 cells survival. Nicotinamide ameliorated HCC-induced reduction in the expression of Nrf2. Moreover, nicotinamide blocked HCC-induced elevation in IGF-1, PKB and JNK-MAPK. In conclusion, nicotinamide produced cytotoxic effects against HCC both in vivo and in vitro. The cytotoxic activity can be explained by inhibition of HCC-induced increased in the expression of IGF-1 and leads to disturbances in the balance between the cell death signal by PKB and MAPK; and the cell survival signal by Nrf2, directing it towards cell survival signals in normal liver cells providing more protection for body against tumor.