scholarly journals Considerations and Technical Pitfalls in the employment of the MTT Assay to Evaluate Photosensitizers for Photodynamic Therapy

2021 ◽  
Vol 11 (6) ◽  
pp. 2603
Author(s):  
Edith Alejandra Carreño ◽  
Anael Viana Pinto Alberto ◽  
Cristina Alves Magalhães de Souza ◽  
Heber Lopes de Mello ◽  
Andrea Henriques-Pons ◽  
...  

Photodynamic therapy (PDT) combines light, a photosensitizing chemical substance, and molecular oxygen to elicit cell death and is employed in the treatment of a variety of diseases, including cancer. The development of PDT treatment strategies requires in vitro assays to develop new photosensitizers. One such assay is the MTT 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide developed in 1983 and widely used in PDT studies. Despite the exponential growth in the number of publications, a uniform MTT protocol for use in the PDT area is lacking. Herein, we list and standardize the conditions to evaluate the photosensitizer methylene blue (MB) in glioblastoma and neuroblastoma cell lines. In addition, we review technical pitfalls and identify several variables that must be taken into consideration in order to provide accurate results with MTT. We conclude that for each cell line we must have a dose-response curve using the MTT assay and good controls for the standardization. Additionally, the optimal values of the time and cell density must be in the linear range of the curve to avoid errors. We describe all relevant points and outline the best normalization techniques to observe the differences between treatments.

Cancers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2904
Author(s):  
Margot Gautier ◽  
Cécile Thirant ◽  
Olivier Delattre ◽  
Isabelle Janoueix-Lerosey

Neuroblastoma, a pediatric cancer of the peripheral sympathetic nervous system, is characterized by an important clinical heterogeneity, and high-risk tumors are associated with a poor overall survival. Neuroblastoma cells may present with diverse morphological and biochemical properties in vitro, and seminal observations suggested that interconversion between two phenotypes called N-type and S-type may occur. In 2017, two main studies provided novel insights into these subtypes through the characterization of the transcriptomic and epigenetic landscapes of a panel of neuroblastoma cell lines. In this review, we focus on the available data that define neuroblastoma cell identity and propose to use the term noradrenergic (NOR) and mesenchymal (MES) to refer to these identities. We also address the question of transdifferentiation between both states and suggest that the plasticity between the NOR identity and the MES identity defines a noradrenergic-to-mesenchymal transition, reminiscent of but different from the well-established epithelial-to-mesenchymal transition.


Author(s):  
John C. Nolan ◽  
Manuela Salvucci ◽  
Steven Carberry ◽  
Ana Barat ◽  
Miguel F. Segura ◽  
...  

Neuroblastoma (NB) is a neural crest-derived tumor, which develops before birth or in early childhood, with metastatic dissemination typically preceding diagnosis. Tumors are characterized by a highly heterogeneous combination of cellular phenotypes demonstrating varying degrees of differentiation along different lineage pathways, and possessing distinct super-enhancers and core regulatory circuits, thereby leading to highly varied malignant potential and divergent clinical outcomes. Cytoskeletal reorganization is fundamental to cellular transformations, including the processes of cellular differentiation and epithelial to mesenchymal transition (EMT), previously reported by our lab and others to coincide with chemotherapy resistance and enhanced metastatic ability of tumor cells. This study set out to investigate the ability of the neuronal miR-124-3p to reverse the cellular transformation associated with drug resistance development and assess the anti-oncogenic role of this miRNA in in vitro models of drug-resistant adrenergic (ADRN) and mesenchymal (MES) neuroblastoma cell lines. Low expression of miR-124-3p in a cohort of neuroblastomas was significantly associated with poor overall and progression-free patient survival. Over-expression of miR-124-3p in vitro inhibited cell viability through the promotion of cell cycle arrest and induction of apoptosis in addition to sensitizing drug-resistant cells to chemotherapeutics in a panel of morphologically distinct neuroblastoma cell lines. Finally, we describe miR-124-3p direct targeting and repression of key up-regulated cytoskeletal genes including MYH9, ACTN4 and PLEC and the reversal of the resistance-associated EMT and enhanced invasive capacity previously reported in our in vitro model (SK-N-ASCis24).


Chemosphere ◽  
1995 ◽  
Vol 30 (9) ◽  
pp. 1709-1715 ◽  
Author(s):  
D. Cova ◽  
R. Perego ◽  
C. Nebuloni ◽  
G. Fontana ◽  
G.P. Molinari

2014 ◽  
Vol 36 (4) ◽  
pp. e219-e223 ◽  
Author(s):  
Christian Luckert ◽  
Georg Eschenburg ◽  
Beate Roth ◽  
Birgit Appl ◽  
Konrad Reinshagen ◽  
...  

2015 ◽  
Vol 15 (1) ◽  
Author(s):  
Elodie Vandenhaute ◽  
Carolin Stump-Guthier ◽  
María Lasierra Losada ◽  
Tobias Tenenbaum ◽  
Henriette Rudolph ◽  
...  

1989 ◽  
Vol 170 (2) ◽  
pp. 511-526 ◽  
Author(s):  
D H Munn ◽  
N K Cheung

Macrophage colony-stimulating factor (M-CSF) is known to stimulate proliferation of monocyte/macrophage progenitors and enhance in vitro antitumor cytotoxicity by murine macrophages. In this paper we have shown that recombinant human M-CSF causes human peripheral blood monocytes to differentiate in culture into metabolically active macrophage-like cells. These cells mediate very efficient antibody-dependent cellular cytotoxicity (ADCC) against human melanoma and neuroblastoma cell lines in the presence of two murine IgG3 mAbs (3F8 and R24). They also mediate antibody-independent cytotoxicity (or cytostasis) to a lesser extent. Human serum had an inconsistent effect on ADCC, but often induced similar high levels of ADCC. Cytotoxicity was measured using a novel ELISA to detect surviving tumor cells after ADCC. Two conventional isotope-release assays (51Cr and [3H]TdR) underestimated or entirely failed to detect ADCC by M-CSF-activated monocytes. Optimal activation occurred with 100-300 U/ml of M-CSF, and required 9-11 d for completion. Most of the M-CSF cultured monocytes expressed the low-affinity Fc receptor (CD16). ADCC by cells of the monocyte/macrophage lineage using murine IgG3 mAbs may have significance for the immunotherapy of human malignancies.


2020 ◽  
Vol 11 (Vol.11, no.3) ◽  
pp. 279-287
Author(s):  
Corina-Elena TIȘLER ◽  
Mîndra-Eugenia BADEA ◽  
Smaranda BUDURU ◽  
Andreea KUI ◽  
Mihaela FLORIA ◽  
...  

Introduction: Photodynamic therapy (PDT) is a therapy involving light and a photosensitising chemical substance, used in conjunction with molecular oxygen in order to elicit cell death (photo-toxicity) and thus ability to kill microbial cells, including bacteria, fungi and viruses. Photodynamic therapy is an alternative method of biofilm disruption and it is considered a new way of microorganism inactivation. It is also an additional procedure to reduce the infection rate in patients, caused by the increasing antimicrobials resistance of bacteria. The aim of this literature review was to evaluate the specific effects and the antibacterial effectiveness of photodynamic therapy using different types of photosensitizers (Erythrosine, Rose Bengal, Toluidine blue, Methylene blue, Ozone, Riboflavin, Curcumin, Chlorhexidine, SAPYR) and a visible light of a specific wavelength for each photosensitizer and to reveal the applications of PDT in periodontics, endodontics, prosthodontics and dental caries. Methods: A research of literature was performed in an attempt to find all the articles published on this topic in the last 10 years. The articles was searched by using a certain combination of different keywords (photodynamic therapy ) and (diode laser ) and (teeth) in PubMed database. Results: A total number of 83 articles were found. After applying inclusion and exclusion criteria, 35 articles were taken into consideration for our study and among them 4 were a manuscript, 3 was a review of literature, 1 was an in vivo evaluation and 27 were in vitro studies. Conclusion: Considering that none of the disinfection methods can completely remove the biofilm, PDT is a therapeutic tool complementary to conventional disinfection, with great applicability in dentistry. PDT showed significantly efficacy in reduction of biofilms. Exposure to light in the presence of a photosensitizing chemical substance helps in the reduction of microbes and the protocols could be recommended for clinical usage, but only together with ‘classic ‘ disinfection.


2021 ◽  
Author(s):  
Balakrishna Koneru ◽  
Ahsan Farooqi ◽  
Thinhh H. Nguyen ◽  
Wan Hsi Chen ◽  
Ashly Hindle ◽  
...  

AbstractCancers overcome replicative immortality by activating either telomerase or an alternative lengthening of telomeres (ALT) mechanism. ALT occurs in ∼ 25% of high-risk neuroblastomas and relapse or progression in ALT neuroblastoma patients during or after front-line therapy is frequent and almost uniformly fatal. Temozolomide + irinotecan is commonly used as salvage therapy for neuroblastoma. Patient-derived cell-lines and xenografts established from relapsed ALT neuroblastoma patients demonstrated de novo resistance to temozolomide + irinotecan (as SN-38 in vitro, P<0.05) and in vivo (mouse event-free survival (EFS) P<0.0001) relative to telomerase-positive neuroblastomas. We observed that ALT neuroblastoma cells manifest constitutive ATM kinase activation due to spontaneous telomere dysfunction while telomerase- positive tumors lacked constitutive ATM activation or spontaneous telomere DNA damage. We demonstrated that induction of telomere dysfunction resulted in ATM activation that in turn conferred resistance to temozolomide + SN-38 (4.2 fold-change in IC50, P<0.001). ATM kinase shRNA knock-down or inhibition using a clinical-stage small molecule inhibitor (AZD0156) reversed resistance to temozolomide + irinotecan in ALT neuroblastoma cell-lines in vitro (P<0.001) and in 4 ALT xenografts in vivo (EFS P<0.0001). AZD0156 showed modest to no enhancement of temozolomide + irinotecan activity in telomerase-positive neuroblastoma cell lines and xenografts. ATR inhibition using AZD6738 did not enhance temozolomide + SN-38 activity in ALT neuroblastoma cell lines. Thus, resistance to chemotherapy in ALT neuroblastoma occurs via ATM kinase activation and was reversed with the ATM inhibitor AZD0156. Combining AZD0156 with temozolomide + irinotecan warrants clinical testing in neuroblastoma.One Statement SummaryATM activation at telomeres confers resistance to DNA damaging chemotherapy in ALT neuroblastoma that was reversed with ATM knockdown or inhibition.


Sign in / Sign up

Export Citation Format

Share Document