Project description:Introduction: The majority of pulmonary carcinoid (PC) tumors can be cured by surgical resection alone, but a significant proportion of patients experience recurrences. PC is insensitive to conventional chemotherapy, and it would be necessary to reveal the molecular mechanisms of metastasis and develop targeted therapeutics. Methods: We performed the comprehensive whole-exome sequencing (WES) of primary tumors and corresponding normal lung tissues from 14 PC patients (including 4 patients who developed postsurgical distant metastasis) and the RNA sequencing of primary tumors from 6 PC patients (including 4 patients who developed postsurgical distant metastasis). Exon array-based gene expression analysis was performed in 25 PC. Results: We identified a total of 139 alterations in 136 genes. MUC6 and SPTA1 were recurrently mutated with the frequency of 21 % (3/14) and 14% (2/14), respectively. The mucin protein family genes including MUC2, MUC4 and MUC6 were mutated in 36% (5/14) in a mutually exclusive manner. The pathway analysis of mutated genes revealed the enrichment of genes involved in the mitogen-activated protein kinase (MAPK) signaling, regulation of actin cytoskeleton and focal adhesion, and transforming growth factor (TGF)-β signaling pathways. RNA sequencing reveals a total of 8 novel fusion transcripts including one derived from chromosomal translocation between the TRIB2 and PRKCE genes. All the 8 fusion genes were detected in primary PC that had developed metastasis after surgical resection. We identified 14 genes (DENND1B, GRID1, CLMN, DENND1B, NRP1, SEL1L3, C5orf13, TNFRSF21, TES, STK39, MTHFD2, OPN3, MET, and HIST1H3C) up-regulated in 5 PC that had relapsed after surgical resection. Conclusions: In this study we identified novel somatic mutations and chromosomal rearrangements by examining clinically aggressive cases that had developed postsurgical metastasis. It is essential to validate their clinical significance in an independent larger patient cohort.

Project description:Hepatectomy generally offers the best chance of long-term survival for patients with hepatocellular carcinoma (HCC). Many studies have shown that hepatectomy accelerates tumor metastasis, but the mechanism remains unclear. In this study, palliative hepatectomy was performed in an orthotopic nude mice model of HCC (MHCC97H) with high metastatic potential. Using Human Tumor Metastasis Microarray, we screened the metastasis-related genes in tumor tissues following palliative resection, and found that Metastasis suppressor 1 (MTSS1) located in the central position of gene function net of residual HCC; MTSS1 was up-regulated in residual tumor after palliative resection. Further studies found that MTSS1 enhanced the metastasis of residual HCC. In hepatitis B-related HCC patients undergone palliative hepatectomy, those with higher MTSS1 mRNA expression accompanied by the activation of matrix metalloproteinase 2 (MMP2) in residual HCC, had earlier residual HCC detection after hepatectomy and poorer survival when compared to those with lower MTSS1 level. In different cell lines, the levels of MTSS1 mRNA increased in parallel with metastatic potential. MTSS1 down regulation via siRNA decreased MMP2 activity, reduced invasive potentials of HCC by 28.9% in vitro, and averted the deteriorated lung metastatic extent in vivo. In conclusion, the poor prognosis of hepatitis B-related HCC patients following palliative hepatectomy associates with elevated MTSS1 mRNA expression; therefore, MTSS1 may provide a new research field for HCC diagnosis and treatment. Eighteen nude mice bearing HCC xenografts were randomized into three groups 14 days after orthotopic implantation: palliative resection group (mice received partial HCC resection with preservation of 2 mm tumor pedicles), sham operation group (mice only undergone an exposure of liver but without resection), and blank control group (mice without further surgical intervention). All mice were sacrificed by cervical dislocation 14 days following palliative resection based on pre-experimental results. The first time surgically removed HCC tissues were named tumor tissues T1; the second time surgically removed HCC tissues from sham operation group were named tumor tissues T2; Tissues from blank control group were named tumor tissues T3; Tissues from palliative resection group were named tumor tissues T4 that was residual HCC. Randomly selected 5 tumor specimens from each group were used for the screen of genes related to metastasis by microarray techniques.

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Whole-exome and RNA sequencing of pulmonary carcinoid reveals chromosomal rearrangements associated with recurrence (Exome)

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