OBJECTIVES: The current study investigated the gene expression profile of hepatocellular carcinoma, HepG2, cells after treatment with Limonene.
METHODS: The concentration that killed 50% of HepG2 cells was used to elucidate the genetic mechanisms of limonene anticancer activity. The apoptotic induction was detected by flow cytometry and confocal fluorescence microscope. Two of the pro-apoptotic events, caspase-3 activation and phosphatidylserine translocation were manifested by confocal fluorescence microscopy. Highthroughput real-time PCR was used to profile 1023 cancer-related genes in 16 different gene families related to the cancer development.
RESULTS: In comparison to untreated cells, limonene increased the percentage of apoptotic cells up to 89.61%, by flow cytometry, and 48.2% by fluorescence microscopy. There was a significant limonene- driven differential gene expression of HepG2 cells in 15 different gene families. Limonene was shown to significantly (>2log) up-regulate and down-regulate 14 and 59 genes, respectively. The affected gene families, from the most to the least affected, were apoptosis induction, signal transduction, cancer genes augmentation, alteration in kinases expression, inflammation, DNA damage repair, and cell cycle proteins.
CONCLUSION: The current study reveals that limonene could be a promising, cheap, and effective anticancer compound. The broad spectrum of limonene anticancer activity is interesting for anticancer drug development. Further research is needed to confirm the current findings and to examine the anticancer potential of limonene along with underlying mechanisms on different cell lines.
MATERIALS AND METHODS: The EGFR intron 1 polymorphism was analysed in three distinct healthy Asian subjects, namely, Chinese (N = 96), Malays (N = 98) and Indians (N = 100). Comparative genomic hybridisation was performed to investigate for changes in DNA copy number in relation to the polymorphic CA dinucleotide repeats in breast tumor tissues (N = 22).
RESULTS: The frequency of short alleles with 14 and 15 CA repeats were most common in the Asian populations and significantly higher than those reported for Caucasians. The frequency of 20 CA repeats was 5%, almost 13-fold lower than previous reports. EGFR amplifications were detected in 23% and 11% of breast tumor tissues harboring short and long CA repeats, respectively.
CONCLUSION: Our results show that the frequency of alleles encoding for short CA dinucleotide repeats is common in Asian populations. EGFR expression and amplification levels were also higher in Asian breast tumor tissues with short CA dinucleotide repeats. These findings suggest that the EGFR intron 1 polymorphism may influence response to treatment with tyrosine kinase inhibitors in breast cancer patients and further studies are warranted.
OBJECTIVES: To screen hypermethylated genes with a microarray approach and to validate selected hypermethylated genes with the methylation-specific polymerase chain reaction (MSPCR).
MATERIALS AND METHODS: Genome-wide analysis of normal oral mucosa and OSCC tissues was conducted using the Illumina methylation microarray. The specified differential genes were selected and hypermethylation status was further verified with an independent cohort sample of OSCC samples. Candidate genes were screened using microarray assay and run by MSPCR analysis.
RESULTS: TP73, PIK3R5, and CELSR3 demonstrated high percentages of differential hypermethylation status.
CONCLUSIONS: Our microarray screening and MSPCR approaches revealed that the signature candidates of differentially hypermethylated genes may possibly become potential biomarkers which would be useful for diagnostic, prognostic and therapeutic targets of OSCC in the near future.