GSH-targeted nanosponges increase doxorubicin-induced toxicity "in vitro" and "in vivo" in cancer cells with high antioxidant defenses

Monocarboxylate transporter 1 (MCT1), a tool to stratify acute myeloid leukemia (AML) patients and a vehicle to kill cancer cells

Dysregulation of glucose/lactate dynamics plays a role in cancer progression, and MCTs are key elements in metabolic remodeling. VEGF is a relevant growth factor in the maintenance of bone marrow microenvironment and it is also important in hematological diseases.

Our aim was to investigate the role of VEGF in the metabolic adaptation of Acute myeloid leukemia (AML) cells by evaluating the metabolic profiles and cell features according to the AML lineage and testing lactate as a metabolic coin.

Our in vitro results showed that AML promyelocytic (HL60) and monocytic (THP1) (but not erythroid- HEL) lineages are well adapted to VEGF and lactate rich environment. Their metabolic adaptation relies on high rates of glycolysis to generate intermediates for PPP to support cell proliferation, and on the consumption of glycolysis-generated lactate to supply biomass and energy production. VEGF orchestrates this metabolic network by regulating MCT1 expression. Bromopyruvic acid (BPA) was proven to be an effective cytotoxic in AML, possibly transported by MCT1.

Our study reinforces that targeting metabolism can be a good strategy to fight cancer. MCT1 expression at the time of diagnosis can assist on the identification of AML patients that will benefit from BPA therapy. Additionally, MCT1 can be used in targeted delivery of conventional cytotoxic drugs.

Extended release delivery of erlotinib glutathione nanosponge for targeting lung cancer

Systemic and uncontrolled administration of erlotinib hydrochloride (ETB) is associated with severe toxicity. A novel targeted and extended release nanosponge (NS) was synthesized from glutathione (GHS) by a one-step reaction between β-cyclodextrin and pyromellitic dianhydride at room temperature for delivery of ETB in lung cancer. Characterization studies were performed using sophisticated instruments. In-vitro release study was performed in the presence of incremental concentrations of GHS which was analyzed using HPLC. Cell cytotoxicity study was evaluated on human lung cancer (A549) cell lines. In-vivo tumour inhibition and biodistribution of ETB-loaded GHS-NS (ETB-NS) were performed on BALB/c mice. NS obtained was spherical, size 212 ± 2.45 nm and high drug entrapment (92.34 ± 5.31%) (p < .001). In-vitro extended drug release (76.89 ± 0.1% release at 168 h), which was directly proportional to the concentration of GHS, demonstrated tumour targeting. There was enhanced in-vitro cytotoxicity and 97.5% inhibition in tumour growth on administering NS when compared to plain ETB (48% inhibition) indicating targeting of NS to the tumour site. Biodistribution study and in-vivo tumour growth inhibition study revealed drug release to the cancerous cell, thus preventing unnecessary drug exposure. ETB-NS exhibits extended drug release proportional to the external GSH concentration.

Immuno-modulatory and cellular antioxidant activities of κ-selenocarrageenan in combination with Epirubicin in H22 hepatoma-bearing mice

BACKGROUND

Human hepatocellular carcinoma (HCC) has a high rate of tumor recurrence and metastasis, resulting in shortened survival time. The aim of this study is to evaluate the synergistic anti-tumor effects and underlying mechanism of κ-selenocarrageenan (KSC) in combination with the chemotherapy drug epirubicin (EPI) in H22 tumor-bearing mice.

METHODS

Hepatocellular carcinoma H22 cells were implanted into mice. After the transplants were successfully established, the animals were divided into four groups: namely the control group, the KSC group, the EPI group and the KSC+EPI group. The effects of KSC and EPI on tumor growth, survival time, thymus index, spleen index, white blood cells (WBC), splenocyte proliferation, natural killer (NK) cell activity, serum TNF-α and IL-2 levels, and antioxidant enzymes in the liver cells were determined.

RESULTS

KSC and/or EPI significantly reduced tumor weight and prolonged the survival time. Furthermore, KSC could attenuate EPI-induced atrophy in the thymus and spleen, as well as other toxicities, which may indicate an additive effect of this combination against organ dysfunction and cellular injury. KSC significantly promoted Con A- and LPS-stimulated splenocyte proliferation, enhanced NK cell activity, and reversed the inhibition of NK activity induced by EPI (P<0.01). In addition, KSC could elevate serum TNF-α and IL-2 levels, increase the GSH-Px, SOD, CAT and GSH activity levels in liver tissue, and reduce MDA content.

CONCLUSIONS

These results suggest that KSC can regulate immune function in mice and suppress the growth of tumor in H22 tumor-bearing mice, and its synergistic antitumor activity with epirubicin may be related to its antioxidant and immuno-modulatory effects.

Silymarin protects against acrylamide-induced neurotoxicity via Nrf2 signalling in PC12 cells

Silymarin (SM) is a well-known antioxidant, anti-inflammatory and anti-cancer compound extracted from the milk thistle. Here, we investigated the protective effect of SM against acrylamide (AA)-induced neurotoxicity, mainly caused by oxidative stress, via activation of the nuclear transcription factor E2-related factor 2 (Nrf2) signalling pathway in PC12 cells. The MTT reduction assay was used to measure cell viability in various drug-treated groups and demonstrated that SM could increase cell viability in AA-treated PC12 cells. We then measured the reactive oxygen species (ROS) levels by the peroxide-sensitive fluorescent probe DCFH-DA and intracellular glutathione (GSH) and malondialdehyde (MDA) levels by absorption spectrophotometry. Our data revealed that SM could reduce ROS and MDA levels and increase GSH levels in AA-induced PC12 cells. To identify a potential mechanism for SM-induced protection, we measured the mRNA and protein expression levels of Nrf2 and its downstream target antioxidants glutathione peroxidase (Gpx), glutamate cysteine ligase catalytic subunit (GCLC) and glutamate cysteine ligase modifier subunit (GCLM) by quantitative real-time PCR and Western blot, respectively. The results suggested that SM could activate Nrf2 signalling and increase the expression of Nrf2, Gpx, GCLC and GCLM in AA-treated PC12 cells. In conclusion, SM can effectively alleviate AA-induced neurotoxicity in PC12 cells.

Breaking the reduced glutathione-activated antioxidant defence for enhanced photodynamic therapy

Photodynamic therapy (PDT) has been applied in cancer treatment by utilizing reactive oxygen species (ROSs) to kill cancer cells.