Immunohistochemistry of deparaffinised sections using antigen retrieval with microwave combined pressure cooking versus immunofluorescence in the assessment of human renal biopsies

Metastasis-associated protein 2 promotes the metastasis of non-small cell lung carcinoma by regulating the ERK/AKT and VEGF signaling pathways

Non-small cell lung carcinoma (NSCLC) is the most common cause of cancer‑associated mortality in the world and accounts for ~85% of human lung cancers. Metastasis‑associated protein 2 (MTA2) is a component of the histone deacetylase complex and serves a role in tumor progression; however, the mechanism through which MTA2 is involved in the progression of NSCLC remains unclear. The aim of the present study was to investigate the expression and function of MTA2 and the MTA2‑mediated signaling pathway in NSCLC cells. Expression of MTA2 and its target genes was analyzed in MTA2‑overexpressing and anti‑MTA2 antibody (AbMTA2)‑treated NSCLC cells, as well as growth, migration, invasion and apoptotic‑resistance. The inhibitory effects on tumor formation were analyzed using AbMTA2‑treated NSCLC cells and in a mouse model. Histological assessment was conducted to analyze the expressions levels of extracellular signal‑regulated kinase (ERK), RAC‑α serine/threonine protein kinase (AKT) and vascular endothelial growth factor (VEGF) in experimental tumors. Results of the present study demonstrated that MTA2 was overexpressed in NSCLC cells. The growth, migration and invasion of NSCLC cells were markedly inhibited by AbMTA2. In addition, it was observed that the ERK/AKT and VEGF signaling pathways were both upregulated in MTA2‑overexpressing NSCLC cells, and downregulated following silencing of MTA2 activation. ERK and AKT phosphorylation levels were downregulated in NSCLC cells and tumors following MTA2 silencing. The in vivo study demonstrated that tumor growth was markedly inhibited following siRNA‑MTA2 treatment. In conclusion, the results of the present study suggested that MTA2 silencing may significantly inhibit the growth and aggressiveness of NSCLC cells. Results from the present study indicated that the mechanism underlying the MTA2‑mediated invasive potential of NSCLC cells involved the ERK/AKT and VEGF signaling pathways, which may be a potential therapeutic target for the treatment of NSCLC.

Diagnostic value of immunohistochemistry on formalin-fixed, paraffin-embedded skin biopsy specimens for bullous pemphigoid

BACKGROUND

Direct immunofluorescence microscopy (DIF) studies constitute the gold standard for diagnosis of bullous pemphigoid (BP) but depend on the availability of specialized laboratories and often on an additional skin biopsy specimen.

OBJECTIVES

To assess the value of immunohistochemical analyses (IHCA) in the diagnosis of BP using formalin-fixed, paraffin-embedded skin biopsy specimens as an alternative to DIF; and to study the correlation between the results of IHCA and the presence of histological subepidermal blister formation and of circulating autoantibodies by indirect immunofluorescence studies using split skin or by enzyme-linked immunosorbent assays.

METHODS

We included all patients newly diagnosed with BP evaluated between 2008 and 2010. There were 51 consecutive skin biopsy specimens obtained from 38 patients with BP with positive DIF.

RESULTS

By IHCA, deposits of immunoreactants were found in 45% of all tested cases. Deposits of C3d, IgG, IgM, IgE and IgA were found in 37%, 23%, 2%, 0% and 0% of cases, respectively. Deposits of C3d and/or IgG were found in 79% of the 24 cases with a blister and in 83% of the 12 cases with subepidermal blistering and positive immunoserological analyses, respectively.

CONCLUSIONS

In contrast to previous studies, our findings in an unselected patient cohort indicate that IHCA are not sufficiently sensitive to replace DIF studies for confirming the diagnosis of BP. IHCA sensitivity significantly increases in the presence of histological blistering and/or of circulating autoantibodies. IHCA represents a potential rescue diagnostic technique only if specialized laboratories and/or a second biopsy specimen for DIF are unavailable.

Value of antibodies to free light chains in immunoperoxidase studies of renal biopsies

AIMS

Because immunoglobulin abnormalities may affect the kidney, investigation of renal biopsies requires immunohistological study of light chains. A problem is that most antibodies to light chains react with whole immunoglobulins as well as free light chains, and there are generally many more whole immunoglobulins than free light chains. The usefulness of antibodies that only detected free light chains was investigated.

METHODS

Antibodies to free light chains were used in an immunoperoxidase method on paraffin sections of 198 renal biopsies, and compared with conventional antibodies against light chains examined by immunofluorescence on 13 frozen sections and by immunoperoxidase on 46 paraffin sections.

RESULTS

Immunofluorescence and immunoperoxidase were concordant on 10 of 13 biopsies. Immunofluorescence detected slight deposition of light chains in three biopsies not shown by immunoperoxidase, of undetermined clinical significance. Using immunoperoxidase, the free light chain antibodies were more sensitive than conventional antibodies, giving much cleaner staining and better detection of deposits in AL amyloid, light chain deposition disease and cryoglobulinaemic glomerulonephritis. The free light chain antibodies showed discordance or ambiguity between immunohistological and clinical findings in seven (4%) of 185 patients with known immunoglobulin status. These included two of 28 cases of AL amyloid that showed no light chain deposition. The method was not designed for detection of light chain restriction in neoplastic plasma or lymphoplasmacytic cells.

CONCLUSIONS

Polyclonal antibodies to free light chains are an improvement on conventional antibodies in immunoperoxidase study of paraffin sections of renal biopsies and are useful in everyday practice.

An efficient immunodetection method for histone modifications in plants

BACKGROUND

Epigenetic mechanisms can be highly dynamic, but the cross-talk among them and with the genome is still poorly understood. Many of these mechanisms work at different places in the cell and at different times of organism development. Covalent histone modifications are one of the most complex and studied epigenetic mechanisms involved in cellular reprogramming and development in plants. Therefore, the knowledge of the spatial distribution of histone methylation in different tissues is important to understand their behavior on specific cells.

RESULTS

Based on the importance of epigenetic marks for biology, we present a simplified, inexpensive and efficient protocol for in situ immunolocalization on different tissues such as flowers, buds, callus, somatic embryo and meristematic tissue from several plants of agronomical and biological importance. Here, we fully describe all the steps to perform the localization of histone modifications. Using this method, we were able to visualize the distribution of H3K4me3 and H3K9me2 without loss of histological integrity of tissues from several plants, including Agave tequilana, Capsicum chinense, Coffea canephora and Cedrela odorata, as well as Arabidopsis thaliana.

CONCLUSIONS

There are many protocols to study chromatin modifications; however, most of them are expensive, difficult and require sophisticated equipment. Here, we provide an efficient protocol for in situ localization of histone methylation that dispenses with the use of expensive and sensitive enzymes. The present method can be used to investigate the cellular distribution and localization of a wide array of proteins, which could help to clarify the biological role that they play at specific times and places in different tissues of various plant species.