Az emberi májrák komparatív genomikai osztályozása

Abstract

Global transcriptome analysis has been successfully applied to characterize various human tumors, including hepatocellular carcinomas. This novel technology can facilitate early diagnosis, as well as prognostic and therapeutic diversification of cancer patients. To enhance access to the genomic information buried in archived pathology samples, we assessed RT-PCR amplification rates in paraffin-embedded tissues preserved in three different fixatives. Reliable amplification could be achieved from all paraffin-embedded specimens, when the amplicon size did not exceed 225 bp. A longer amplicon size resulted in rapid decrease of yield and reproducibility. In addition, formalin provided superior morphology and better reactivity with claudin-4 and -7 immunohistochemistry. Amplification of the initial sample is often required before transcriptome analysis of clinical specimens could be performed. We introduced a random nonamer primed T3 polymerase reaction into the conventional linear RNA amplification protocol. The modified T3T7 method generated a sense strand product ideal for synthesizing indirectly labeled cDNA templates. Microarray analysis of amplified frozen and laser-microdissected Myc and Myc/TGFalpha mouse liver tumors confirmed good reproducibility (r=0.9) of the reaction and conservation of original transcriptional patterns (r=0.78). Finally, we tested the utility of expression profiling for the classification of human HCC samples. By comparing expression data from HGF-treated c-Met conditional knock-out and control primary mouse hepatocytes, we identified 690 HGF/c-Met target genes. Functional analysis of the significant gene set implicated c-Met as key regulator of hepatocyte motility and oxidative homeostasis. Cross comparison of the c-Met-induced transcription signature with human HCC expression profiles revealed a group of tumors (27%) with potentially activated c-Met signaling (MET+). These tumors were characterized by higher vascular invasion rate, increased microvessel density, and shortened survival. A prediction model based on 111 cross-species conserved c-Met signature genes was able to diversify HCC patients into good and bad prognostic groups with 83-95% accuracy. Our results therefore demonstrate that careful experimental design and state-of-the-art laboratory methods could open the way for global expression profiling of archived and limited availability pathologic samples. Comparative functional genomics based analysis of the cancer transcriptome could lead to novel molecular classification systems which are essential for the introduction of individualized cancer therapeutics.

Preclinical Trials for Prevention of Tumor Progression of Hepatocellular Carcinoma by LZ-8 Targeting c-Met Dependent and Independent Pathways

“…Moreover, high HGF level in serum and deregulated expression of c-Met in HCCs are closely associated with early recurrence [ 20 ] and patients with high c-Met expressing HCCs usually have shorter 5-year survival rate after curative surgical resection [ 19 – 22 ]. In addition, a group of HCCs (27%) with a c-Met-induced transcriptional signature was characterized by a higher rate of vascular invasion [ 23 ]. In vitro studies have also revealed the effects of HGF on metastatic changes of HCC, including EMT, migration, and invasion [ 24 – 26 ].…”

GRP78 confers the resistance to 5-FU by activating the c-Src/LSF/TS Axis in hepatocellular carcinoma

“…Hepatocellular carcinoma (HCC) is the fifth common cancer worldwide whose mortality rate parallels with its incidence [ 1 ]. Rapid growth and early vascular invasion are the most important characteristics of HCC [ 2 - 4 ]. The treatment options for HCC depend on the stages and grades of this disease.…”

Impact of MET targeting on tumor-associated angiogenesis and growth of MET mutations-driven models of liver cancer

“…Similarly, Zou et al demonstrated that crizotinib, a non-specific MET TKI, which is currently in phase III clinical trial for the treatment of non-small cell lung cancer, was able to inhibit in vitro tubulogenesis of primary endothelial cells [25]. As potential interplay between aberrant MET signaling and angiogenesis in HCC, a study by Kaposi-Novak reported a MET aberrant expression-related transcriptional signature in a group of HCCs that were characterized by higher rate of vascular invasion and increased microvessel density [26], emphasizing therefore the potential role of MET-related angiogenesis in the pathogenesis of these tumors.…”