Assessment of the Carcinogenicity of Carbon Nanotubes in the Respiratory System.

Marcella Barbarino,Antonio Giordano

doi:10.3390/cancers13061318

Marcella Barbarino, Antonio Giordano

Open Access

https://doi.org/10.3390/cancers13061318

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Journal: Cancers	Publication Date: Mar 15, 2021
Citations: 29	License type: CC BY 4.0

Affiliation: University of Siena, Temple University

Abstract

Simple SummaryMalignant mesothelioma is an aggressive cancer of the membranes covering the lung and chest cavity (pleura) or the abdomen (peritoneum), mainly linked to asbestos exposure. Asbestos is a proven human carcinogen but its use is far from being universally banned and the forecasts on the incidence of mesothelioma over the next several years are far from optimistic. Carbon nanotubes are a promising type of nano-materials used in the field of nanotechnology for a wide range of applications. However, the similarities between asbestos and CNTs have raised many concerns about their danger and are still the subject of intense research. Keeping in mind that the asbestos tragedy could have been prevented, the aim of this study is to review the recent scientific evidence on CNTs carcinogenicity.In 2014, the International Agency for Research on Cancer (IARC) classified the first type of carbon nanotubes (CNTs) as possibly carcinogenic to humans, while in the case of other CNTs, it was not possible to ascertain their toxicity due to lack of evidence. Moreover, the physicochemical heterogeneity of this group of substances hamper any generalization on their toxicity. Here, we review the recent relevant toxicity studies produced after the IARC meeting in 2014 on an homogeneous group of CNTs, highlighting the molecular alterations that are relevant for the onset of mesothelioma. Methods: The literature was searched on PubMed and Web of Science for the period 2015–2020, using different combinations keywords. Only data on normal cells of the respiratory system after exposure to fully characterized CNTs for their physico-chemical characteristics were included. Recent studies indicate that CNTs induce a sustained inflammatory response, oxidative stress, fibrosis and histological alterations. The development of mesothelial hyperplasia, mesothelioma, and lungs tumors have been also described in vivo. The data support a strong inflammatory potential of CNTs, similar to that of asbestos, and provide evidence that CNTs exposure led to molecular alterations known to have a key role in mesothelioma onset. These evidences call for an urgent improvement of studies on exposed human populations and adequate systems for monitoring the health of workers exposed to this putative carcinogen.

Highlights

Malignant pleural mesothelioma (MPM) is an aggressive cancer of the pleural membranes covering the lungs and is strongly linked to asbestos exposure
The present review aims to provide an overview of the recent relevant toxicity studies produced after the International Agency for Research on Cancer (IARC) meeting in 2014 restricting analysis on a homogeneous group of carbon nanotubes (CNTs): standard materials from the Joint Repository Center (JCR) and well-characterized commercial or in-house-made CNTs produced by catalytic carbon vapor deposition (CVD)
We focused our analysis on the results obtained using reference CNTs (NM-400, NM-401, NM-402, and NM-403), with fully characterized commercial and in-house CNTs produced using the CVD method, which is currently one of the principal techniques used for CNT synthesis

Summary

Introduction

Malignant pleural mesothelioma (MPM) is an aggressive cancer of the pleural membranes covering the lungs and is strongly linked to asbestos exposure. MPM generally manifests in an advanced stage after a latency period of 30–40 years following asbestos exposure. 30 years later (1935), the first association between asbestos and lung cancer was described [5,6] and it was another 10 years passed before asbestos exposure was correlated with pleural tumors, in the work of Wedler in 1943 [7] and the doctorate thesis of Wyres in 1946 [8]. In 1977 [9] and 1987 [10], the International Agency for Research on Cancer (IARC) concluded that asbestos is a human carcinogen and that the size and shape of the fibers influence the incidence of tumors. In 2006 [11] and 2009 [12] asbestos exposure was correlated with an increased risk of other cancers, such as laryngeal and ovarian cancer

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