Simultaneous down-regulation of tumor suppressor genes RBSP3/CTDSPL, NPRL2/G21 and RASSF1A in primary non-small cell lung cancer

<p>Abstract</p> <p>Background</p> <p>The short arm of human chromosome 3 is involved in the development of many cancers including lung cancer. Three bona fide lung cancer tumor suppressor genes namely <it>RBSP3 </it>(AP20 region),<it>NPRL2 </it>and <it>RASSF1A </it>(LUCA region) were identified in the 3p21.3 region. We have shown previously that homozygous deletions in AP20 and LUCA sub-regions often occurred in the same tumor (P < 10^-6).</p> <p>Methods</p> <p>We estimated the quantity of <it>RBSP3, NPRL2, RASSF1A, GAPDH, RPN1 </it>mRNA and <it>RBSP3 </it>DNA copy number in 59 primary non-small cell lung cancers, including 41 squamous cell and 18 adenocarcinomas by real-time reverse transcription-polymerase chain reaction based on TaqMan technology and relative quantification.</p> <p>Results</p> <p>We evaluated the relationship between mRNA level and clinicopathologic characteristics in non-small cell lung cancer. A significant expression decrease (≥2) was found for all three genes early in tumor development: in 85% of cases for <it>RBSP3</it>; 73% for <it>NPRL2 </it>and 67% for <it>RASSF1A </it>(P < 0.001), more strongly pronounced in squamous cell than in adenocarcinomas. Strong suppression of both, <it>NPRL2 </it>and <it>RBSP3 </it>was seen in 100% of cases already at Stage I of squamous cell carcinomas. Deregulation of <it>RASSF1A </it>correlated with tumor progression of squamous cell (P = 0.196) and adenocarcinomas (P < 0.05). Most likely, genetic and epigenetic mechanisms might be responsible for transcriptional inactivation of <it>RBSP3 </it>in non-small cell lung cancers as promoter methylation of <it>RBSP3 </it>according to NotI microarrays data was detected in 80% of squamous cell and in 38% of adenocarcinomas. With NotI microarrays we tested how often LUCA (<it>NPRL2, RASSF1A</it>) and AP20 (<it>RBSP3</it>) regions were deleted or methylated in the same tumor sample and found that this occured in 39% of all studied samples (P < 0.05).</p> <p>Conclusion</p> <p>Our data support the hypothesis that these TSG are involved in tumorigenesis of NSCLC. Both genetic and epigenetic mechanisms contribute to down-regulation of these three genes representing two tumor suppressor clusters in 3p21.3. Most importantly expression of <it>RBSP3, NPRL2 </it>and <it>RASSF1A </it>was simultaneously decreased in the same sample of primary NSCLC: in 39% of cases all these three genes showed reduced expression (P < 0.05).</p

Tumor suppressor function of the SEMA3B gene in human lung and renal cancers

The SEMA3B gene is located in the 3p21.3 LUCA region, which is frequently affected in different types of cancer. The objective of our study was to expand our knowledge of the SEMA3B gene as a tumor suppressor and the mechanisms of its inactivation. In this study, several experimental approaches were used: tumor growth analyses and apoptosis assays in vitro and in SCID mice, expression and methylation assays and other. With the use of the small cell lung cancer cell line U2020 we confirmed the function of SEMA3B as a tumor suppressor, and showed that the suppression can be realized through the induction of apoptosis and, possibly, associated with the inhibition of angiogenesis. In addition, for the first time, high methylation frequencies have been observed in both intronic (32-39%) and promoter (44-52%) CpG-islands in 38 non-small cell lung carcinomas, including 16 squamous cell carcinomas (SCC) and 22 adenocarcinomas (ADC), and in 83 clear cell renal cell carcinomas (ccRCC). Correlations between the methylation frequencies of the promoter and the intronic CpG-islands of SEMA3B with tumor stage and grade have been revealed for SCC, ADC and ccRCC. The association between the decrease of the SEMA3B mRNA level and hypermethylation of the promoter and the intronic CpG-islands has been estimated in renal primary tumors (P < 0.01). Using qPCR, we observed on the average 10- and 14-fold decrease of the SEMA3B mRNA level in SCC and ADC, respectively, and a 4-fold decrease in ccRCC. The frequency of this effect was high in both lung (92-95%) and renal (84%) tumor samples. Moreover, we showed a clear difference (P < 0.05) of the SEMA3B relative mRNA levels in ADC with and without lymph node metastases. We conclude that aberrant expression and methylation of SEMA3B could be suggested as markers of lung and renal cancer progression

Differential Expression of CHL1 Gene during Development of Major Human Cancers

CHL1 gene (also known as CALL) on 3p26.3 encodes a one-pass trans-membrane cell adhesion molecule (CAM). Previously CAMs of this type, including L1, were shown to be involved in cancer growth and metastasis.We used Clontech Cancer Profiling Arrays (19 different types of cancers, 395 samples) to analyze expression of the CHL1 gene. The results were further validated by RT-qPCR for breast, renal and lung cancer. Cancer Profiling Arrays revealed differential expression of the gene: down-regulation/silencing in a majority of primary tumors and up-regulation associated with invasive/metastatic growth. Frequent down-regulation (>40% of cases) was detected in 11 types of cancer (breast, kidney, rectum, colon, thyroid, stomach, skin, small intestine, bladder, vulva and pancreatic cancer) and frequent up-regulation (>40% of cases)--in 5 types (lung, ovary, uterus, liver and trachea) of cancer. Using real-time quantitative PCR (RT-qPCR) we found that CHL1 expression was decreased in 61% of breast, 60% of lung, 87% of clear cell and 89% papillary renal cancer specimens (P<0.03 for all the cases). There was a higher frequency of CHL1 mRNA decrease in lung squamous cell carcinoma compared to adenocarcinoma (81% vs. 38%, P = 0.02) without association with tumor progression.Our results suggested that CHL1 is involved in the development of different human cancers. Initially, during the primary tumor growth CHL1 could act as a putative tumor suppressor and is silenced to facilitate in situ tumor growth for 11 cancer types. We also suggested that re-expression of the gene on the edge of tumor mass might promote local invasive growth and enable further metastatic spread in ovary, colon and breast cancer. Our data also supported the role of CHL1 as a potentially novel specific biomarker in the early pathogenesis of two major histological types of renal cancer

Peripheral T-Cell Lymphoma of the Submandibular Salivary Gland as an Unusual Manifestation of Richter’s Syndrome: A Case Report and Literature Review

Richter’s syndrome is the development of high-grade non-Hodgkin lymphoma (NHL) or Hodgkin lymphoma in patients with chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL). In most patients with Richter’s syndrome, the high-grade NHL is diffuse large B-cell lymphoma. Only a small minority of CLL/SLL patients develop T-cell malignancies. Herein, we describe a 40-year-old male patient presenting with peripheral T-cell lymphoma not otherwise specified (PTCL-NOS) in the submandibular salivary gland, two years after the diagnosis of CLL/SLL. The PTCL-NOS consisted of small lymphocytes, which complicated diagnosis. Immunohistochemical, cytological, and molecular studies allowed the correct diagnosis of composite lymphoma (SLL/PTCL-NOS) of the submandibular salivary gland. The PTCL-NOS had a cytotoxic phenotype and aberrant expression of CD79a. There was no evidence to suggest that the PTCL-NOS of the submandibular salivary gland developed from an intimately associated submandibular lymph node or by PTCL-NOS dissemination. A review of the literature and presented case suppose that the PTCLs developed following CLL/SLL have the cytotoxic phenotype and can clinically mimic typical Richter’s syndrome

Tumor Suppressor Properties of Small C-Terminal Domain Phosphatases in Clear Cell Renal Cell Carcinoma

Clear cell renal cell carcinoma (ccRCC) accounts for 80–90% of kidney cancers worldwide. Small C-terminal domain phosphatases CTDSP1, CTDSP2, and CTDSPL (also known as SCP1, 2, 3) are involved in the regulation of several important pathways associated with carcinogenesis. In various cancer types, these phosphatases may demonstrate either antitumor or oncogenic activity. Tumor-suppressive activity of these phosphatases in kidney cancer has been shown previously, but in general case, the antitumor activity may be dependent on the choice of cell line. In the present work, transfection of the Caki-1 cell line (ccRCC morphologic phenotype) with expression constructs containing the coding regions of these genes resulted in inhibition of cell growth in vitro in the case of CTDSP1 (p CTDSPL (p CTDSP2. The analysis of The Cancer Genome Atlas (TCGA) data showed differential expression of some of CTDSP genes and of their target, RB1. These results were confirmed by quantitative RT-PCR using an independent sample of primary ccRCC tumors (n = 52). We observed CTDSPL downregulation and found a positive correlation of expression for two gene pairs: CTDSP1 and CTDSP2 (rs = 0.76; p CTDSPL and RB1 (rs = 0.38; p CTDSP1, CTDSP2, CTDSPL, and RB1 with poor survival of ccRCC patients (p CTDSP1, CTDSP2, and RB1 were differently expressed in two subtypes of ccRCC—ccA and ccB, characterized by different survival rates. These results confirm that CTDSP1 and CTDSPL have tumor suppressor properties in ccRCC and reflect their association with the more aggressive ccRCC phenotype

Relative mRNA level of the <i>SEMA3B</i> gene in NSCLC (A) and ccRCC (B).

<p>QPCR data, additional samplings. Light grey columns—samples without metastases, dark grey columns—samples with lymph node or distant metastases. The numbers of primary tumors correspond to those in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0123369#pone.0123369.s001" target="_blank">S1 Table</a>. Mean values ± standard deviations for 3 replicates are represented.</p

<i>SEMA3B</i> gene expression level (A), copy number (C) and methylation status of its two CpG-islands (B) in the same ccRCC samples.

<p>Semi-quantitative PCR (A, C) and MSP (B) data. Numbers of primary tumors correspond to those in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0123369#pone.0123369.s001" target="_blank">S1 Table</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0123369#pone.0123369.g005" target="_blank">Fig 5B</a>. (A) Light grey columns—samples without metastases, dark grey columns—samples with lymph node or distant metastases. (B) 1-st CpG—promoter CpG-island, 2-nd CpG—intronic CpG-island. Grey squares show methylated CpG-islands, white squares—unmethylated. (C) Grey squares show hemi- or homozygous deletions of the 5’Sema5 marker, black—amplification, white squares—retention. Assessed mean values ± error bars are represented in the “A” part.</p

Inhibition of tumor growth by <i>SEMA3B</i> re-expression.

<p>The growth rate of U2020 cells (U7111 clone) in SCID mice: blue line—U2020 cells without <i>SEMA3B</i> expression (+ doxycycline, 4 mice), red and yellow line—U2020 cells with <i>SEMA3B</i> expression (- doxycycline, 4 mice and 1 mouse respectively). *—no expression of <i>SEMA3B</i> gene according to the Northern blot (data not shown). One +dox and one—dox mice were withdrawn from the study after one month.</p