Simultaneous detection of a cell surface antigen and apoptosis by microwave-sensitized TUNEL assay on paraffin sections

Inhibition of lung cancer by vitamin D depends on downregulation of histidine-rich calcium-binding protein

Introduction

Intrinsic vitamin D affects the proliferation, apoptosis, invasion, metastasis, and tumorigenesis of lung cancer by regulating tumor signaling pathways. Histidine-rich calcium-binding protein (HRC) maintains Ca²⁺ homeostasis, which plays crucial roles in the occurrence and development of cancer.

Objectives

Our study aims to investigate the ability of vitamin D in the regulation of HRC and the role of HRC playing in lung cancer.

Methods

We investigated the effects of vitamin D on lung cancer and the underlying mechanisms, by measuring HRC and vitamin D receptor (VDR) expression in lung cancer, paracancer, and normal tissues from patients using immunohistochemistry, western blotting, and real time RT-PCR. We transfected H460 lung cancer cells (supplemented or not with vitamin D) with PX458-HRC and pcDNA3.1-HRC plasmids and injected mice with lung cancer cells harboring pcDNA3.1-vector or pcDNA3.1-HRC plasmids.

Results

Vitamin D inhibited HRC expression and H460 cell migration and proliferation, and promoted apoptosis compared with controls. The expression of HRC and VDR was significantly upregulated and downregulated, respectively, in lung cancer versus paracancer or normal tissues. Cell proliferation and migration were reduced, apoptotic cells were more and tumors were smaller in mice treated with vitamin D/cholecalciferol cholesterol emulsion (CCE) than in vitamin D/CCE+HRC^+/+ mice.

Conclusion

Vitamin D inhibited lung cancer tumor growth, migration, and proliferation by downregulating HRC.

The PI3K/Akt and NF-κB signaling pathways are involved in the protective effects of Lithocarpus polystachyus (sweet tea) on APAP-induced oxidative stress injury in mice

Acetaminophen (APAP)-induced acute liver injury (ALI) is a health issue that has gradually attracted attention, and is often regarded as a model of drug-induced hepatotoxicity. The leaves of Lithocarpus polystachyus Rehd. (named as “sweet tea”, ST) usually serve as tea drink and folk medicine for healthcare in the southwest part of China. In previous reports, it has been proven to protect various animal models, except for APAP-induced liver injury model. Therefore, this study initially explored the protective effect of ST leaf extract (STL-E) on hepatotoxicity induced by APAP in ICR mice. STL-E of 50 and 100 mg kg⁻¹ were given to each group for 7 days. ALI was intraperitoneally induced by APAP treatment (i.p. 250 mg per kg body weight). Biochemical markers, levels of inflammatory factors, histopathological staining and western blotting were used to analyze the inflammation and apoptosis of liver tissues. Interestingly, the treatment with STL-E significantly attenuated APAP-induced liver injury (p < 0.05). Moreover, STL-E partially mitigated APAP-induced liver injury by effectively activating the PI3K/Akt pathway and inhibiting the NF-κB pathway. In a word, STL-E protected liver against APAP-induced hepatotoxicity by inhibiting the PI3K/Akt-mediated apoptosis signal pathway and inhibiting the NF-κB-mediated signaling pathway.

Acetaminophen (APAP)-induced acute liver injury (ALI) is a health issue that has gradually attracted attention, and is often regarded as a model of drug-induced hepatotoxicity.

The Antitumor Activity of the Novel Compound Jesridonin on Human Esophageal Carcinoma Cells

Jesridonin, a small molecule obtained through the structural modification of Oridonin, has extensive antitumor activity. In this study, we evaluated both its in vitro activity in the cancer cell line EC109 and its in vivo effect on tumor xenografts in nude mice. Apoptosis induced by Jesridonin was determined using an MTT assay, Annexin-V FITC assay and Hoechest 33258 staining. Apoptosis via mitochondrial and death receptor pathways were confirmed by detecting the regulation of MDM2, p53, and Bcl-2 family members and by activation of caspase-3/-8/-9. In addition, vena caudalis injection of Jesridonin showed significant inhibition of tumor growth in the xenograft model, and Jesridonin-induced cell apoptosis in tumor tissues was determined using TUNEL. Biochemical serum analysis of alkaline phosphatase (ALP), alanine transaminase (ALT), aspartate transaminase (AST), gamma-glutamyl transferase (GGT), total protein (TP) and albumin (ALB) indicated no obvious effects on liver function. Histopathological examination of the liver, kidney, lung, heart and spleen revealed no signs of JD-induced toxicity. Taken together, these results demonstrated that Jesridonin exhibits antitumor activity in human esophageal carcinomas EC109 cells both in vitro and in vivo and demonstrated no adverse effects on major organs in nude mice. These studies provide support for new drug development.

Bcl-2/caspase 3 mucosal imbalance favors T cell resistance to apoptosis in dogs with inflammatory bowel disease

Canine idiopathic inflammatory bowel disease (IBD) is believed to result from complex interplay between genetic, microbial, and immunologic factors. Abnormal cell death by apoptosis may result in the persistence of activated intestinal T cells that contribute to mucosal inflammation and clinical severity. To test this hypothesis, we investigated the mucosal expression of pro- and anti-apoptotic proteins in different intestinal compartments and their association with inflammatory indices in dogs with IBD. Apoptosis of lamina propria (LP) T cells in duodenal, ileal, and colonic tissues in control and IBD dogs was analyzed by caspase 3/Bcl-2 immunohistochemistry and TUNEL assays. Densities and distributions of LP caspase 3 and Bcl-2 cells were correlated to histopathologic lesions and the clinical activity index (CIBDAI). Compared to control tissues, IBD dogs had significantly (P<0.01) fewer caspase 3 cells in colonic mucosa. Double immunostaining identified the majority of apoptotic cells as TUNEL(+)/caspase 3(+). Within intestinal mucosa of IBD dogs, there were significantly greater numbers of Bcl-2 cells at the apical and basilar villus in the duodenum as compared to the colon and to the apical and basilar villus in the ileum (P<0.001 for all comparisons). There were significantly greater numbers of Bcl-2 cells at the apical and basilar villus of the duodenum but significantly fewer numbers of Bcl-2 cells at the apical villus of the ileum in IBD dogs compared with controls (P<0.001, P<0.001, and P<0.02, respectively). There was a significant association between the number of Bcl-2 cells in the duodenum of IBD dogs and the CIBDAI (P<0.001 each for mild, moderate and severe clinical IBD). In conclusion, apoptosis of T lymphocytes varies within intestinal compartments of dogs with IBD. Mucosal imbalance of Bcl-2/caspase 3 expression favors T cell resistance to apoptosis which may contribute to T cell accumulation and chronic intestinal inflammation, similar to human IBD.

Simultaneous detection and semiquantification of DNA damage in normal and apoptotic cells: triple-immunofluorescent labeling using DAPI, antibodies, and TUNEL

We developed a triple-labeling immunofluorescence technique that simultaneously identifies total DNA (DAPI), DNA damage (antibodies), and dead cells [terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL)-positive cells] and a method that semiquantifies DNA damage in paraffin-embedded tissues. Using this technique in combination with our analysis method, scientists can now simultaneously detect and compare the relative amounts of DNA damage of almost any kind (except single-strand and double-strand breaks), using indirect fluorescent antibody labeling, in both normal and dying cells of different tissues. Simultaneous labeling of DNA damage and dead or TUNEL-positive cells can reduce processing costs and analysis time, and can lead to discoveries concerning how cells die from different DNA damages. We used increasing doses of UV (290 to 400 nm) radiation to create DNA damage in the form of cyclobutane pyrimidine dimers and 6-4 photoproducts that kill some of the cells in 3-dimensional tissue-engineered skin and vaginal samples. We describe a protocol that reliably detects and semiquantifies DNA damage in both normal and apoptotic cells. We show this triple-labeling immunofluorescence technique and analysis method yields linear UV dose response curves for damage to DNA bases that allows semiquantification of cyclobutane pyrimidine dimers and calculation of its repair rate (T=1 and 24 h), whereas TUNEL allows quantification of the number of apoptotic cells. Scientists can now create beautiful fluorescent pictures that simultaneously detect DNA damage in both normal and apoptotic cells to assess and semiquantify the damage to understand better how different insults lead to the cell's demise.

In situ detection of apoptosis by the TUNEL assay: an overview of techniques

Apoptosis, or programmed cell death, plays an important role in normal development and homeostasis of adult tissues. Apoptosis has also been linked to many disease states, including cancer. One of the biochemical hallmarks of apoptosis is the generation of free 3'-hydroxyl termini on DNA via cleavage of chromatin into single and multiple oligonuleosome-length fragments. The TdT-mediated dUTP-biotin nick end labeling (TUNEL) assay exploits this biochemical hallmark by labeling the exposed termini of DNA, thereby enabling visualization of nuclei containing fragmented DNA. This review outlines the general method for in situ TUNEL staining of cultured cells and tissue sections, and highlights recent improvements in the technique and limitations of the assay.

Amifostine protective effect on cisplatin-treated rat testis

Cisplatin is a potent drug used in clinical oncology but causes spermatogenesis damage. Amifostine is a drug used against toxicity caused by ionizing irradiation and chemotherapeutic drugs. Since cisplatin provokes fertility and induces germ cell apoptosis and necrosis, we proposed to evaluate the amifostine cytoprotective action on testes of cisplatin-treated rats. Thirty-day-old prepubertal Wistar rats received a single cisplatin dose of 5 mg/kg and were killed after 3, 6, and 12 hr. The hematoxylin-eosin stained testicular sections were submitted to histological, morphometric, and stereological analysis. The terminal deoxynucleotidyl transferase-mediated deoxyuridinetriphosphate nick end-labeling (TUNEL) method was used to label apoptotic cells. TUNEL-positive and TUNEL-negative germ cells with abnormal nuclear morphology (ANM) were scored. Significant alterations of greater part of the parameters occurred in the cisplatin-treated group (CE) compared to the group that received amifostine before the cisplatin-treatment (ACE); however, testicular weight and volume did not vary between these groups. Tubular diameter was reduced in CE in comparison to ACE rats, while interstitial tissue and lymphatic space volume and volume density were significantly higher in CE rats; interstitial testicular edema probably occurred in cisplatin-treated rats. CE rats showed important histological alterations, which were more accentuated than in ACE rats. The numerical densities of apoptotic germ cells and TUNEL-negative cells with ANM were lower in ACE than in CE rats. In conclusion, the amifostine previously administered to prepubertal rats reduced the testicular damage caused by cisplatin. We conclude that amifostine partially protected the rat seminiferous epithelium against cisplatin toxicity.