Valid application of western blotting

Targeting MERTK on tumour cells and macrophages: a potential intervention for sporadic and NF2-related meningioma and schwannoma tumours

Meningioma and schwannoma are common tumours of the nervous system. They occur sporadically or as part of the hereditary NF2-related schwannomatosis syndrome. There is an unmet need for new effective drug treatments for both tumour types. In this paper, we demonstrate overexpression/activation of TAM (TYRO3/AXL/MERTK) receptors (TAMs) and overexpression/release of ligand GAS6 in patient-derived meningioma tumour cells and tissue. For the first time, we reveal the formation of MERTK/TYRO3 heterocomplexes in meningioma and schwannoma tissue. We demonstrate the dependence of AXL and TYRO3 expression on MERTK in both tumour types, as well as interdependency of MERTK and AXL expression in meningioma. We show that MERTK and AXL contribute to increased proliferation and survival of meningioma and schwannoma cells, which we inhibited in vitro using the MERTK/FLT3 inhibitor UNC2025 and the AXL inhibitor BGB324. UNC2025 was effective in both tumour types with superior efficacy over BGB324. Finally, we found that TAMs are expressed by tumour-associated macrophages in meningioma and schwannoma tumours and that UNC2025 strongly depleted macrophages in both tumour types.

Targeting histone deacetylase 6 (HDAC6) to enhance radiation therapy in meningiomas in a 2D and 3D in vitro study

BACKGROUND

External radiation therapy (RT) is often a primary treatment for inoperable meningiomas in the absence of established chemotherapy. Histone deacetylase 6 (HDAC6) overexpression, commonly found in cancer, is acknowledged as a driver of cellular growth, and inhibiting HDACs holds promise in improving radiotherapeutic efficacy. Downregulation of HDAC6 facilitates the degradation of β-catenin. This protein is a key element in the Wnt/β-catenin signalling pathway, contributing to the progression of meningiomas.

METHODS

In order to elucidate the associations and therapeutic potential of HDAC6 inhibitors (HDAC6i) in conjunction with RT, we administered Cay10603, HDAC6i, to both immortalised and patient-derived meningioma cells prior to RT in this study.

FINDINGS

Our findings reveal an increase in HDAC6 expression following exposure to RT, which is effectively mitigated with pre-treated Cay10603. The combination of Cay10603 with RT resulted in a synergistic augmentation of cytotoxic effects, as demonstrated through a range of functional assays conducted in both 2D as well as 3D settings; the latter containing syngeneic tumour microenvironment (TME). Radiation-induced DNA damage was augmented by pre-treatment with Cay10603, concomitant with the inhibition of β-catenin and minichromosome maintenance complex component 2 (MCM2) accumulation within the nucleus. This subsequently inhibited c-myc oncogene expression.

INTERPRETATION

Our findings demonstrate the therapeutic potential of Cay10603 to improve the radiosensitisation and provide rationale for combining HDAC6i with RT for the treatment of meningioma.

FUNDING

This work was funded by Brain Tumour Research Centre of Excellence award to C Oliver Hanemann.

Applications of western blot technique: From bench to bedside

Western blot (WB) or immunoblot is a workhorse method. It is commonly used by biologists for study of different aspects of protein biomolecules. In addition, it has been widely used in disease diagnosis. Despite some limitations such as long time, different applications of WB have not been limited. In the present review, we have summarized scientific and clinical applications of WB. In addition, we described some new generation of WB techniques.

(-)-Epicatechin reduces muscle waste after complete spinal cord transection in a murine model: role of ubiquitin-proteasome system

The skeletal muscle mass reduces 30-60% after spinal cord injury, this is mostly due to protein degradation through ubiquitin-proteasome system. In this work, we propose that the flavanol (-)-epicatechin, due its widespread biological effects on muscle health, can prevent muscle mass decrease after spinal cord injury. Thirty-six female Long Evans rats were randomized into 5 groups: (1) Spinal cord injury 7 days, (2) Spinal cord injury + (-)-epicatechin 7 days, (3) Spinal cord injury 30 days, (4) Spinal cord injury + (-)-epicatechin 30 days and (5) Sham (Only laminectomy). Hind limb perimeter, muscle cross section area, fiber cross section area and ubiquitin-proteasome system protein expression together with total protein ubiquitination were assessed. At 30 days Spinal cord injury group lost 49.52 ± 2.023% of muscle cross section area (-)-epicatechin treated group lost only 24.28 ± 15.45% being a significant difference. Ubiquitin-proteasome markers showed significant changes. FOXO1a increased in spinal cord injury group vs Sham (-)-epicatechin reduced this increase. In spinal cord injury group MAFbx increased significantly vs Sham but decrease in (-)-epicatechin treatment group at 30 days. At 7 and 30 days MuRF1 increased in the spinal cord injury and decreased in the (-)-epicatechin group. The global protein ubiquitination increases after spinal cord injury, epicatechin treatment induce a significant decrease in protein ubiquitination. These results suggest that (-)-epicatechin reduces the muscle waste after spinal cord injury through down regulation of the ubiquitin-proteasome system.

The role of cytochromes p450 and aldo-keto reductases in prognosis of breast carcinoma patients

Metabolism of anticancer drugs affects their antitumor effects. This study has investigated the associations of gene expression of enzymes metabolizing anticancer drugs with therapy response and survival of breast carcinoma patients. Gene expression of 13 aldo-keto reductases (AKRs), carbonyl reductase 1, and 10 cytochromes P450 (CYPs) was assessed using quantitative real-time polymerase chain reaction in tumors and paired adjacent nonneoplastic tissues from 68 posttreatment breast carcinoma patients. Eleven candidate genes were then evaluated in an independent series of 50 pretreatment patients. Protein expression of the most significant genes was confirmed by immunoblotting. AKR1A1 was significantly overexpressed and AKR1C1-4, KCNAB1, CYP2C19, CYP3A4, and CYP3A5 downregulated in tumors compared with control nonneoplastic tissues after correction for multiple testing. Significant association of CYP2B6 transcript levels in tumors with expression of hormonal receptors was found in the posttreatment set and replicated in the pretreatment set of patients. Significantly higher intratumoral levels of AKR1C1, AKR1C2, or CYP2W1 were found in responders to neoadjuvant chemotherapy compared with nonresponders. Patients with high AKR7A3 or CYP2B6 levels in the pretreatment set had significantly longer disease-free survival than patients with low levels. Protein products of AKR1C1, AKR1C2, AKR7A3, CYP3A4, and carbonyl reductase (CBR1) were found in tumors and those of AKR1C1, AKR7A3, and CBR1 correlated with their transcript levels. Small interfering RNA-directed knockdown of AKR1C2 or vector-mediated upregulation of CYP3A4 in MDA-MB-231 model cell line had no effect on cell proliferation after paclitaxel treatment in vitro. Prognostic and predictive roles of drug-metabolizing enzymes strikingly differ between posttreatment and pretreatment breast carcinoma patients. Mechanisms of action of AKR1C2, AKR7A3, CYP2B6, CYP3A4, and CBR1 should continue to be further followed in breast carcinoma patients and models.