Simple two-step purification and characterisation of peroxidase from Citrullus colocynthis.

Peroxidase is a biotechnologically important enzyme. The purification of peroxidase from the root of Citrullus colocynthis was carried out in a simple two-step process with maximum purity level. The sample was extracted in a high salt buffer, and the enzyme was partially purified with a Q-Sepharose anion exchange column. Final purification was carried out with HighLoad 16/600 Superdex G-75 column. The purified protein was analysed with SDS gel electrophoresis, which suggested a single band of approximately 35 kDa. Further, the enzyme was identified with the help of Mass spectrometric analysis using an ESI-QTOF Mass spectrometer. The study will be helpful for the isolation and its commercial uses in biotechnology.

Acidotic and hypoxic tumor microenvironment induces changes to histone acetylation and methylation in oral squamous cell carcinoma.

Hypoxia and acidosis are ubiquitous hallmarks of the tumor microenvironment (TME), and in most solid cancers they have been linked to rewired cancer cell metabolism. These TME stresses are linked to changes in histone post-translational modifications (PTMs) such as methylation and acetylation, which lead to tumorigenesis and drug resistance. Hypoxic and acidotic TME cause changes in histone PTMs by impacting the activities of histone-modifying enzymes. These alterations are yet to be extensively explored in oral squamous cell carcinoma (OSCC), one of the most prevalent cancers in developing countries. Hypoxic, acidotic, and hypoxia with acidotic TME affecting histone acetylation and methylation in the CAL27 OSCC cell line was studied using LC-MS-based proteomics. The study identified several well-known histone marks, in the context of their functionality in gene regulation, such as H2AK9Ac, H3K36me3, and H4K16Ac. The results provide insights into the histone acetylation and methylation associated with hypoxic and acidotic TME, causing changes in their level in a position-dependent manner in the OSCC cell line. Hypoxia and acidosis, separately and in combination, cause differential impacts on histone methylation and acetylation in OSCC. The work will help uncover tumor cell adaptation to these stress stimuli in connection with histone crosstalk events.

PX-12 synergistically enhances the therapeutic efficacy of vorinostat under hypoxic tumor microenvironment in oral squamous cell carcinoma in vitro.

Hypoxia is a characteristic feature of solid tumors, including oral squamous cell carcinoma (OSCC), which causes therapeutic resistance. The hypoxia-inducible factor 1-alpha (HIF-1α) is a key regulator of hypoxic tumor microenvironment (TME) and a promising therapeutic target against solid tumors. Among other HIF-1α inhibitors, vorinostat (suberoylanilide hydroxamic acid, SAHA) is a histone deacetylase inhibitor (HDACi) targeting the stability of HIF-1α, and PX-12 (1-methylpropyl 2-imidazolyl disulfide) is a thioredoxin-1 (Trx-1) inhibitor preventing accumulation of HIF-1α. HDACis are effective against cancers; however, they are accompanied by several side effects along with an emerging resistance against it. This can be overcome by using HDACi in a combination regimen with Trx-1 inhibitor, as their inhibitory mechanisms are interconnected. HDACis inhibit Trx-1, leading to an increase in the production of reactive oxygen species (ROS) and inducing apoptosis in cancer cells; thus, the efficacy of HDACi can be elevated by using a Trx-1 inhibitor. In this study, we have tested the EC50 (half maximal effective concentration) doses of vorinostat and PX-12 on CAL-27 (an OSCC cell line) under both normoxic and hypoxic conditions. The combined EC50 dose of vorinostat and PX-12 is significantly reduced under hypoxia, and the interaction of PX-12 with vorinostat was evaluated by combination index (CI). An additive interaction between vorinostat and PX-12 was observed in normoxia, while a synergistic interaction was observed under hypoxia. This study provides the first evidence for vorinostat and PX-12 synergism under hypoxic TME, at the same time highlighting the therapeutically effective combination of vorinostat and PX-12 against OSCC in vitro.

IVS I-5 (G > C) is associated with changes to the RBC membrane lipidome in response to hydroxyurea treatment in ß-thalassemia patients.

The red blood cell membrane loses its integrity during hemoglobinopathies like ß-thalassemia and sickle cell disease. Various mutations have been associated with ß-thalassemia, the most prevalent of which is the IVS-1-5 (G > C) mutation. It is associated with poor prognosis of the disease with a dependency on transfusion. Here, we have investigated the effect of IVS mutation and the administration of hydroxyurea on the red blood cell membrane lipidome isolated from patients using a liquid chromatography coupled to tandem mass spectrometry based approach to identify changes in the red blood cell membrane lipidome of patients with/without the mutation and being/not being administered hydroxyurea. A total of 50 patients, with/without hydroxyurea treatment, were recruited and 62 lipid species were identified in all groups after statistical analyses using fold change analysis, ANOVA and lipids with higher VIP values extracted from the OPLS-DA loading plot. The presence of the IVS mutation showed altered expression levels of various lipid species as compared to non-IVS individuals, such as phosphatidylcholines, steroids, phenol lipids and fatty acids. Significant changes were though found with the administration of hydroxyurea where both the IVS and non-IVS groups showed a marked increase in complex lipids of the membrane, while a decrease was observed in those without hydroxyurea administration showing degradation of these membrane lipids. This study is the first to report changes incurred by IVS mutation and hydroxyurea administration in red blood cell membranes extracted from ß-thalassemia patients. Hydroxyurea administration has been perceived to improve the lipid profile of the red blood cell membrane in both IVS and non-IVS patients.