Disruption of NADPH homeostasis by total flavonoids from Adinandra nitida Merr. ex Li leaves triggers ROS-dependent p53 activation leading to apoptosis in non-small cell lung cancer cells.

ETHNOPHARMACOLOGICAL RELEVANCE: Adinandra nitida Merr. ex Li leaves serve as a herbal tea and hold a significant role in traditional Chinese medicine, being applied to assist in tumor treatment. Flavonoids present the primary bioactive constituents in Adinandra nitida Merr. ex Li leaves. AIM OF THE STUDY: To explore the potential of total flavonoids from Adinandra nitida Merr. ex Li Leaves (TFAN) in inhibiting non-small cell lung cancer (NSCLC) and further elucidate the underlying mechanisms. MATERIALS AND METHODS: Human NSCLC cell lines and normal lung cell line were employed to assess the impact of TFAN (0-160 µg/mL for 24, 28 and 72 h) on cell proliferation in vitro. Immunofluorescence (IF) staining gauged p53 expression changes in NSCLC cells under TFAN present condition (150 µg/mL for 24 h). In vivo study utilized NSCLC cell derived xenograft tumors in nude mice, administering TFAN orally (200 and 400 mg/kg) for 14 days. Immunohistochemistry assessed Cleaved Caspase 3 expression change in A549 xenograft tumors treated with TFAN (400 mg/kg for 14 days). RNA-seq and KEGG analysis identified gene expression changes and enriched processes in A549 xenograft tumors treated with TFAN. CM-H2DCFDA and metabolomics assessed ROS level and GSH/GSSG pool changes in A549 cells under TFAN present condition. Cell viability assay and IF staining assessed A549 cell proliferation and p53 expression changes under H2O2-induced oxidative stress (0-40 µM for 24 h) and TFAN present conditions. GSEA and N-Acetyl-L-cysteine (NAC) rescue (0-1 µM for 24 h) analyzed the impact of TFAN on GSH de novo synthesis. NADPH/NADP+ pool measurement and NADPH rescue (0-10 µM for 24 h) analyzed the impact of TFAN on GSH salvage synthesis. GC-FID and HPLC-MS were utilized to detect ethanol and ethyl acetate residues, and to characterize the chemical constituents in TFAN, respectively. The total flavonoid content of TFAN was determined using a 330 nm wavelength. RESULTS: TFAN significantly inhibited A549 cells (wild-type p53) but not NCI-H1299 cells (p53-deficient), NCI-H596 cells (p53-mutant) or BEAS-2B in vitro. IF staining validated p53 genotype for the cell lines and revealed an increase in p53 expression in A549 cells after TFAN treatment. In vivo, TFAN selectively inhibited A549 xenograft tumor growth without discernible toxicity, inducing apoptosis evidenced by Cleaved Caspase 3 upregulation. RNA-seq and KEGG analysis suggested ROS biosynthesis was involved in TFAN-induced p53 activation in A549 cells. Elevated ROS level in TFAN-treated A549 cells were observed. Moreover, TFAN sensitized A549 cells to H2O2-induced oxidative stress, with higher p53 expression. Additionally, A549 cells compensated with GSH de novo synthesis under TFAN present condition, confirmed by GSEA and NAC rescue experiment. TFAN disrupted NADPH homeostasis to impair GSH salvage biosynthesis, supported by NADPH/NADP+ change and NADPH rescue experiment. The chemical constituents of TFAN, with acceptable limits for ethanol and ethyl acetate residues and a total flavonoid content of 68.87%, included Catechin, Epicatechin, Quercitroside, Camellianin A, and Apigenin. CONCLUSION: The disruption of NADPH homeostasis by TFAN triggers ROS-dependent p53 activation that leads to apoptotic cell death, ultimately suppressing NSCLC growth. These findings offer potential therapeutic implications of Adinandra nitida Merr. ex Li leaves in combating NSCLC.

G6PD Maintains Redox Homeostasis and Biosynthesis in LKB1-Deficient KRAS-Driven Lung Cancer.

Cancer cells depend on nicotinamide adenine dinucleotide phosphate (NADPH) to combat oxidative stress and support reductive biosynthesis. One major NAPDH production route is the oxidative pentose phosphate pathway (committed step: glucose-6-phosphate dehydrogenase, G6PD). Alternatives exist and can compensate in some tumors. Here, using genetically-engineered lung cancer model, we show that ablation of G6PD significantly suppresses KrasG12D/+;Lkb1-/- (KL) but not KrasG12D/+;p53-/- (KP) lung tumorigenesis. In vivo isotope tracing and metabolomics revealed that G6PD ablation significantly impaired NADPH generation, redox balance and de novo lipogenesis in KL but not KP lung tumors. Mechanistically, in KL tumors, G6PD ablation caused p53 activation that suppressed tumor growth. As tumor progressed, G6PD-deficient KL tumors increased an alternative NADPH source, serine-driven one carbon metabolism, rendering associated tumor-derived cell lines sensitive to serine/glycine depletion. Thus, oncogenic driver mutations determine lung cancer dependence on G6PD, whose targeting is a potential therapeutic strategy for tumors harboring KRAS and LKB1 co-mutations.

Inhibition of autophagy and MEK promotes ferroptosis in Lkb1-deficient Kras-driven lung tumors.

LKB1 and KRAS are the third most frequent co-mutations detected in non-small cell lung cancer (NSCLC) and cause aggressive tumor growth. Unfortunately, treatment with RAS-RAF-MEK-ERK pathway inhibitors has minimal therapeutic efficacy in LKB1-mutant KRAS-driven NSCLC. Autophagy, an intracellular nutrient scavenging pathway, compensates for Lkb1 loss to support Kras-driven lung tumor growth. Here we preclinically evaluate the possibility of autophagy inhibition together with MEK inhibition as a treatment for Kras-driven lung tumors. We found that the combination of the autophagy inhibitor hydroxychloroquine (HCQ) and the MEK inhibitor Trametinib displays synergistic anti-proliferative activity in KrasG12D/+;Lkb1-/- (KL) lung cancer cells, but not in KrasG12D/+;p53-/- (KP) lung cancer cells. In vivo studies using tumor allografts, genetically engineered mouse models (GEMMs) and patient-derived xenografts (PDXs) showed anti-tumor activity of the combination of HCQ and Trametinib on KL but not KP tumors. We further found that the combination treatment significantly reduced mitochondrial membrane potential, basal respiration, and ATP production, while also increasing lipid peroxidation, indicative of ferroptosis, in KL tumor-derived cell lines (TDCLs) and KL tumors compared to treatment with single agents. Moreover, the reduced tumor growth by the combination treatment was rescued by ferroptosis inhibitor. Taken together, we demonstrate that autophagy upregulation in KL tumors causes resistance to Trametinib by inhibiting ferroptosis. Therefore, a combination of autophagy and MEK inhibition could be a novel therapeutic strategy to specifically treat NSCLC bearing co-mutations of LKB1 and KRAS.

Hydrolyzed seawater pearl tablet modulates the immunity via attenuating Th1/Th2 imbalance in an immunosuppressed mouse model.

OBJECTIVE: To investigate whether Hydrolyzed Seawater Pearl tablet (HSPT) could modulate the Th1/Th2 imbalance in an immunosuppressed mouse model with Th1 to Th2 shift induced by Cyclosporine A (CsA) which can be used in the clinical treatment of Th2 to Th1 shift diseases, and explore the possible mechanism for the adjuvant therapeutic efficacy of HSPT on recurrent respiratory infections (RRI) and acquired immune deficiency syndrome (AIDS). METHODS: The mice were randomly divided into six groups of five animals each, namely normal group, model group, lentinan polysaccharide tablet (LPT) group and three HPST treated groups. HPST treated groups were administered with HPST (0.51, 1.02, 2.04 g/kg) via intragastric gavage (i.g) for 30 consecutive days. LPT used as reference drug for positive control, LPT group was administered with LPT (8.2 mg/kg) for 30 consecutive days. Normal group and model group were received distilled water. The animals in model group, LPT group and HPST treated groups were injected intraperitoneally with CsA (50 mg/kg) to establish the immunosuppressed mice model with Th1 to Th2 shift on the 20th, 22nd and 24th day, one hour after the administration of the respective treatment. Animals were sacrificed one hour after the last administration to collect blood and splenic tissue. The proportion of T cells including CD8+ and CD4+ T cells, Th1 and Th2 in peripheral blood of experimental mice were measured by flow cytometric. The protein level in serum and mRNA level in splenic tissue of experimental mice for interleukin (IL)-2, IL-12, interferon-γ (IFN-γ), IL-4, IL-6, IL-10 and IL-13 were measured by enzyme linked immunosorbent assay and fluorescence quantitative polymerase chain reaction respectively. RESULTS: HSPT elevated the proportion of T cells including both CD8+ and CD4+ T cells, in which the proportion of Th1 and Th2 cells increased, while the ratio of Th1/Th2 cells decreased in peripheral blood of the immunosuppressed mouse model with Th1 to Th2 shift induced by CsA. Furthermore, HSPT elevated both protein and mRNA level of Th1-type cytokines IL-2 and IFN-γ, while had no significant effect on protein and mRNA level of Th1-type cytokine IL-12 and Th2-type cytokines IL-4, IL-6, IL-10, IL- 13 in mouse model. CONCLUSION: Our findings suggest that HSPT can increase proportion of T cells including both CD8+ and CD4+ T cells and induce Th2 to Th1 shift in both cells and cytokines, which probably was the mechanism to account for the adjuvant therapeutic efficacy of HSPT on RRI and AIDS.

Autophagy compensates for Lkb1 loss to maintain adult mice homeostasis and survival.

Liver kinase B1 (LKB1), also known as serine/threonine kinase 11 (STK11) is the major energy sensor for cells to respond to metabolic stress. Autophagy degrades and recycles proteins, macromolecules, and organelles for cells to survive starvation. To assess the role and cross-talk between autophagy and Lkb1 in normal tissue homeostasis, we generated genetically engineered mouse models where we can conditionally delete Stk11 and autophagy essential gene, Atg7, respectively or simultaneously, throughout the adult mice. We found that Lkb1 was essential for the survival of adult mice, and autophagy activation could temporarily compensate for the acute loss of Lkb1 and extend mouse life span. We further found that acute deletion of Lkb1 in adult mice led to impaired intestinal barrier function, hypoglycemia, and abnormal serum metabolism, which was partly rescued by the Lkb1 loss-induced autophagy upregulation via inhibiting p53 induction. Taken together, we demonstrated that autophagy and Lkb1 work synergistically to maintain adult mouse homeostasis and survival.

Mangiferin exerts neuroprotective activity against lead-induced toxicity and oxidative stress via Nrf2 pathway.

Objective: The study was designed to assess the beneficial role of mangiferin (MGN) in lead (Pb)-induced neurological damages in the activation of Nrf2-governed enzymes, genes and proteins. Methods: A total of 96 weaned Wistar rats (48 males and 48 females, 26- to 27-day-old), weighing 50-80 g were used. The experiment was performed in six groups: normal group (control, n = 16), model group (chronic Pb exposed, n = 16), Dimercaptosuccinic acid (DMSA)-treated group (positive control, Pb + DMSA, n = 16), three MGN-treated groups with different doses (Pb + MGN, n = 48). Normal group freely had access to purified water. DMSA-treated group was given DMSA, which was clinically used as the standard treatment for moderate Pb poisoning, at 50 mg/kg (2 mL suspension with purified water) by intragastric gavage (ig) 4 continual days a week for 4 weeks, MGN-treated groups were given MGN at 50, 100, or 200 mg/kg (2 mL suspension with purified water) by ig daily for 4 weeks. At the end of the treatment, all rats were sacrificed and the brain samples were collected. The haematoxylin and eosin (H&E) staining was used for observation of histopathology. Commercial kit, real-time quantitative polymerase chain reaction (RT-qPCR), Western-blot and immunohistochemistry (IHC) detection were used to detect the mRNA and protein expression. Results: Eight weeks exposure to Pb-containing water resulted in pathological alterations, anti-oxidative system disorder in the brain, all of which were blocked by MGN in a Nrf2-dependent manner. Nrf2 downstream enzymes such as HO-1, NQO1, γ-GCS were activated. Nrf2, GCLC, GCLM, HO-1 mRNA and total Nrf2, Nuclear Nrf2, γ-GCS, HO-1 protein expression were affected too. Conclusion: MGN ameliorated morphological damage in the hippocampus. Its neuroprotective effects were achieved by the activation of the Nrf2 downstream genes. The data from this in vitro study indicates that MGN targeting Nrf2 activation is a feasible approach to reduce adverse health effects associated with Pb exposure. Thus, MGN could be an effective candidate agent for the Pb-induced oxidative stress and neurotoxicity in the human body.

[Study on the effect of extracts from the leaves of Phyllanthus emblica on immune function of mice].

OBJECTIVE: To explore the effect of extracts from the leaves of Phyllanthus emblica (PLFs) on the immune function of mice. METHODS: 70 Kunming mice were choosed to conduct the acute toxicity test of PLFs. The mice were randomly divided into four groups: PLFs high-dosage group, mid-dosage group, low-dosage group and control group. The high,mid,low-dosage groups were treated with PLFs 1.982, 0.991 and 0.496 g/kg respectively per day. The same volume of double distilled water was given to the control group. All by intragastric administration for 7 d. The animals were killed and indexes of thymus and spleen were calculated. The expurgation index K and phagocyte index a were detected after the mice being injected with a dilute India ink through caudal vein. In addition, prepared spleen cells conventionally,the activity of Natural Killer cells was measured and the proliferation of T and B cells were detected. The effect of the extracts on serum hemolysin was detected after the SRBC was injected into the enterocoelia. RESULTS: The LD50 of PLFs was 9. 911 g/kg. Compared with the control group, the indexes of thymus and spleen in the treatment groups had no markedly difference (P > 0.05). The high- and mid-dosage groups could obviously improve the expurgation index K (P < 0.05), phagocyte index alpha (P < 0.05) and NK cell activity (P < 0.05). CONCLUSION: The extracts from Phyllanthus emblica leaves can promote nonspecific immunity immune function in mice.