No detection of simian virus 40 in malignant mesothelioma in Korea

Association Study of Pleural Mesothelioma and Oncogenic Simian Virus 40 in the Crocidolite-Contaminated Area of Dayao County, Yunnan Province, Southwest China

Background: In Dayao County, Chuxiong Yi Autonomous Prefecture, Yunnan Province, Southwest China, 5% of the surface is scattered with blue asbestos, which has a high incidence of pleural mesothelioma (PMe). Simian virus 40 (SV40) is a small circular double-stranded DNA polyomavirus that can cause malignant transformation of normal cells of various human and animal tissue types and promote tumor growth. In this study, we investigate whether oncogenic SV40 is associated with the occurrence of PMe in the crocidolite-contaminated area of Dayao County, Yunnan Province, Southwest China. Methods: Tumor tissues from 51 patients with PMe (40 of whom had a history of asbestos exposure) and pleural tissues from 12 non-PMe patients (including diseases such as pulmonary maculopathy and pulmonary tuberculosis) were collected. Three pairs of low-contamination risk primers (SVINT, SVfor2, and SVTA1) were used to detect the gene fragment of SV40 large T antigen (T-Ag) by polymerase chain reaction (PCR). The presence of SV40 T-Ag in PMe tumor tissues and PMe cell lines was detected by Western blotting and immunohistochemical staining with SV40-related antibodies (PAb 101 and PAb 416). Results: PCR, Western blotting, and immunohistochemical staining results showed that the Met5A cell line was positive for SV40 and contained the SV40 T-Ag gene and protein. In contrast, the various PMe cell lines NCI-H28, NCI-H2052, and NCI-H2452 were negative for SV40. PCR was negative for all three sets of low-contamination risk primers in 12 non-PMe tissues and 51 PMe tissues. SV40 T-Ag was not detected in 12 non-PMe tissues or 51 PMe tissues by immunohistochemical staining. Conclusion: Our data suggest that the occurrence of PMe in the crocidolite-contaminated area of Yunnan Province may not be related to SV40 infection and that crocidolite exposure may be the main cause of PMe. The Clinical Trial Registration number: 2020-YXLL20.

Binding of SV40's Viral Capsid Protein VP1 to Its Glycosphingolipid Receptor GM1 Induces Negative Membrane Curvature: A Molecular Dynamics Study

The binding of the pentameric capsid protein VP1 of simian virus 40 to its glycosphingolipid receptor GM1 is a key step for the entry of the virus into the host cell. Recent experimental studies have shown that the interaction of variants of soluble VP1 pentamers with giant unilamellar vesicles composed of GM1, DOPC, and cholesterol leads to the formation of tubular membrane invaginations to the inside of the vesicles, mimicking the initial steps of endocytosis. We have used coarse-grained and atomistic molecular dynamics (MD) simulations to study the interaction of VP1 with GM1/DOPC/cholesterol bilayers. In the presence of one VP1 protein, we monitor the formation of small local negative curvature and membrane thinning at the protein binding site as well as reduction of area per lipid. These membrane deformations are also observed under cholesterol-free conditions. However, here, the number of GM1 molecules attached to the VP1 binding pockets increases. The membrane curvature is slightly increased for asymmetric GM1 distribution that mimics conditions in vivo, compared to symmetric GM1 distributions which are often applied in experiments. Slightly smaller inward curvature was observed in atomistic control simulations. Binding of four VP1 proteins leads to an increase of the average intrinsic area per lipid in the protein binding leaflet. Membrane fluctuations appear to be the driving force of VP1 aggregation, as was previously shown for membrane-adhering particles because no VP1 aggregation is observed in the absence of a lipid membrane.

Estimated future incidence of malignant mesothelioma in South Korea: Projection from 2014 to 2033

Malignant mesothelioma is a malignant tumor on the pleura or the peritoneum caused mostly by asbestos. Although asbestos is not currently used in South Korea, the incidence of mesothelioma is increasing due to its long latent period. This study predicted the incidence of malignant mesothelioma in South Korea over the next 20 years using an age-period-cohort (APC) model. Data regarding mesothelioma incidence from 1994–2013 were acquired from the Korea Central Cancer Registry (KCCR). Demographic data, including prospective resident data, were acquired from the Korean Statistical Information Service (KOSIS) for 1994–2033. An APC model with Møller’s power-link function was utilized to predict the incidence of mesothelioma. It was predicted that 2,380 and 1,199 new cases of mesothelioma in men and women, respectively, would occur over the next 20 years. For both sexes, the mesothelioma incidence rate was predicted to be greater in 2029–2033 compared to that in 2009–2013 (men, 0.282 vs 0.563; women, 0.155 vs 0.217). For men, the age-standardized incidence rate was predicted to be slightly greater in 2029–2033 relative to the rate in 2009–2013 (0.228 vs 0.235), while the age-standardized incidence rate in women decreased within the same timeframe (0.113 vs 0.109). The changes in mesothelioma incidence were mostly caused by changes in the population structure due to aging and not by changes in the mesothelioma risk ratio. The results of this study project a continuous increase in mesothelioma incidence in South Korea over the next 20 years. Although the projected increase in mesothelioma incidence was not related to an increase in the mesothelioma risk ratio, continuous preventive efforts are necessary to reduce the exposure to asbestos and prevent the trend from worsening.

Pleural mesothelioma: an institutional experience of 66 cases

Background

Malignant mesothelioma of the pleura is an aggressive tumor known to be associated with asbestos. Histological diagnosis of mesothelioma is challenging and is usually aided by immunohistochemical markers.

Methods

During an 18-year period (1995-2012), 66 patients with pleural mesothelioma were diagnosed at the Samsung Medical Center in Seoul. We reviewed hematoxylin and eosin and immunohistochemical slides of pleural mesothelioma and evaluated their pathological and clinical features.

Results

The male-to-female ratio was 1.75:1, and age of patients ranged from 28 to 80 years with an average age of 56.84 years. Twenty-two out of 66 patients underwent curative pneumonectomy. Follow-up data was available in 60 patients (90.9%), and 50 of them (83.3%) died from the disease. The average overall survival was 15.39 months. Histologically, the epithelioid type was the most common, followed by the sarcomatoid and the biphasic types. Epidemiologic information was not available in most cases, and only one patient was confirmed to have a history of asbestos exposure.

Conclusions

Malignant mesothelioma of the pleura is a fatal tumor, and the therapeutic benefit of pneumonectomy remains unproven. The combination of calretinin, Wilms tumor 1, HMBE-1, and thyroid transcription factor-1 may provide high diagnostic accuracy in diagnosing mesothelioma.

The role of key genes and pathways involved in the tumorigenesis of Malignant Mesothelioma

Malignant Mesothelioma (MM) is a very aggressive cancer with low survival rates and often diagnosed at an advanced stage. Several players have been implicated in the development of this cancer, such as asbestos, erionite and the simian virus 40 (SV40). Here, we have reviewed the involvement of erionite, SV40, as well as, the role of several genes (p16(INK4a), p14(ARF), NF2, LATS2, SAV, CTNNB1 and among others), the pathways (RAS, PI3K, Wnt, BCL and Hippo), and their respective roles in the development of MM.

The function, mechanisms, and role of the genes PTEN and TP53 and the effects of asbestos in the development of malignant mesothelioma: a review focused on the genes' molecular mechanisms

The malignant mesothelioma is an aggressive form of cancer with a mean survival rate of less than a year. Moreover, environmental exposure to minerals is an important factor in the development of malignant mesothelioma (MM), especially the mineral asbestos, which has a well-documented role in MM, and more recently, the mineral erionite has been proven to be a strong carcinogenic inducer of MM. In addition, the virus simian virus 40 has been implicated as a co-carcinogenic player in MM. However, the molecular mechanisms involved in the pathogenesis of this cancer are still not fully understood. Indeed, it is known that several genes are altered or mutated in MM, among those are p16(INK4A), p14(ARF), and neurofibromatosis type II. Furthermore, TP53 has been reported to be mutated in the majority of the cancers; however, in MM, it is very uncommon mutations in this gene. Also, the PTEN gene has been shown to play an important role in endometrial cancer and glioblastoma, although the role of PTEN in MM has yet to be established. Taken altogether, this review focuses on the historical aspects, molecular mechanisms, interaction with other genes and proteins, and the role of these genes in MM. Lastly, this review questions the cancer theory of the two hits because the functions of both PTEN and TP53 are not fully explained by this theory.