Abstract: Purpose: NOTCH signaling pathway is essential in T-cell development and NOTCH1 mutations are frequently present in T-cell acute lymphoblastic leukemia (T-ALL). To gain insight into its clinical significance, NOTCH1 mutation was investigated in 77 patients with T-ALL. Experimental Design: Detection of NOTCH1 mutation was done using reverse transcription-PCR amplification and direct sequencing, and thereby compared according to the clinical/biological data of the patients. Results: Thirty-two mutations were identified in 29 patients (with dual mutations in 3 cases), involving not only the heterodimerization and proline/glutamic acid/serine/threonine domains as previously reported but also the transcription activation and ankyrin repeat domains revealed for the first time. These mutations were significantly associated with elevated WBC count at diagnosis and independently linked to short survival time. Interestingly, the statistically significant difference of survival according to NOTCH1 mutations was only observed in adult patients ( & gt;18 years) but not in pediatric patients (≤18 years), possibly due to the relatively good overall response of childhood T-ALL to the current chemotherapy. NOTCH1 mutations could coexist with HOX11, HOX11L2, or SIL-TAL1 expression. The negative effect of NOTCH1 mutation on prognosis was potentiated by HOX11L2 but was attenuated by HOX11. Conclusion: NOTCH1 mutation is an important prognostic marker in T-ALL and its predictive value could be even further increased if coevaluated with other T-cell-related regulatory genes. NOTCH pathway thus acts combinatorially with oncogenic transcriptional factors on T-ALL pathogenesis.

Abstract: Retinoic acid–induced gene G (RIG-G), a gene originally identified in all-trans retinoic acid–treated NB4 acute promyelocytic leukemia cells, is also induced by IFNα in various hematopoietic and solid tumor cells. Our previous work showed that RIG-G possessed a potent antiproliferative activity. However, the mechanism for the transcriptional regulation of RIG-G gene remains unknown. Here, we report that signal transducer and activator of transcription (STAT) 2 together with IFN regulatory factor (IRF)-9 can effectively drive the transcription of RIG-G gene by their functional interaction through a STAT1-independent manner, even without the tyrosine phosphorylation of STAT2. The complex IRF-9/STAT2 is both necessary and sufficient for RIG-G gene expression. In addition, IRF-1 is also able to induce RIG-G gene expression through an IRF-9/STAT2–dependent or IRF-9/STAT2–independent mechanism. Moreover, the induction of RIG-G by retinoic acid in NB4 cells resulted, to some extent, from an IFNα autocrine pathway, a finding that suggests a novel mechanism for the signal cross-talk between IFNα and retinoic acid. Taken together, our results provide for the first time the evidence of the biological significance of IRF-9/STAT2 complex, and furnish an alternative pathway modulating the expression of IFN-stimulated genes, contributing to the diversity of IFN signaling to mediate their multiple biological properties in normal and tumor cells. [Cancer Res 2009;69(8):3673–80]

Abstract: The lung cancer incidence in Xuanwei (XW) City and Fuyuan (FY) County in Yunnan Province of China is among the highest in China, owing to high levels of air pollution produced by combustion of smoky coal. This epidemiology profile provides a unique opportunity for identifying the carcinogenic mechanism underlying air pollution. Here, we analyze the genome sequences of 14 XW/FY non-small-cell lung cancers and their paired normal tissues, and report a mean of 289 somatic exonic mutations and 71 genomic rearrangements/tumor. Among the recurring mutated genes, calcium signaling and ion channel genes are the most frequently altered gene category. Higher mutation rate in calcium signaling genes is confirmed by genomic resequencing in 65 XW/FY patients and 85 patients from control regions. Small interfering RNA mediated silencing shows that inactivation of calcium channel leads to inhibition of lung cancer cells, suggesting a role for calcium signaling molecules in air pollution-related carcinogenesis leading to lung cancer. Citation Format: Guang-Biao Zhou, Xian-Jun Yu, Li-Chuan Wu, Yun-Chao Huang, Gao-Feng Li, Zhe-Sheng Wen, Sai-Juan Chen, Yi Cao, Sheng-Yue Wang, Min-Jun Yang, Zhu Chen. Genomic abnormalities in air pollution-related lung cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3187. doi:10.1158/1538-7445.AM2014-3187

Abstract: The formation of fusion genes between NUP98 and members of the HOX family represents a critical factor for the genesis of acute leukemia or acute transformation of chronic myeloid leukemia (CML). To gain insights into the molecular mechanisms underlying the leukemogenesis of NUP98-HOX fusion products, we cloned NUP98-PMX1 from a CML-blast crisis patient with t(1;11) as a secondary chromosomal translocation, and functionally studied the fusion products in detail through various molecular and protein biochemical assays. In addition to many interesting features, we have found that the NUP98-PMX1 fusion protein exerts a repressive effect on PMX1 or serum response factor–mediated c-FOS activation, probably through the recruitment of a common corepressor histone deacetylase 1 by FG domains of the NUP98-PMX1 fusion protein. Moreover, we have provided evidence that the FG domains of NUP98-PMX1 and two other NUP98-containing fusion proteins, i.e., NUP98-HOXA9 and NUP98-HOXC11, all exhibit dual binding ability to both CREB binding protein, a coactivator, and histone deacetylase 1, a corepressor. Accordingly, we have hypothesized that this dual binding activity is shared by most, if not all, NUP98-HOX-involved fusion proteins, enabling these fusion proteins to act as both trans-activators and trans-repressors, and contributing to the genesis of acute leukemia or acute transformation of CML. (Cancer Res 2006; 66(9): 4584-90)

Abstract: Acute myeloid leukemia (AML) is a group of heterogeneous diseases with considerable diversities in terms of clinical consequences and biological implications. Abnormalities in genes that encode transcription factors and tyrosine kinases represent two classes of the most frequently detected genetic events in human AMLs. Recently, a new category of gene mutations associated with epigenetic regulation have also been implicated in leukemogenesis. For example, the mutations of IDH1, IDH2 and TET2 might result in a hypermethylation phenotype with impairment of hematopoietic differentiation. Chromosomal translocations involving MLL which actually encoding a histone methyltransferase are mostly found in acute monocytic leukemia (or AML-M5). Discovery of these epigenetic events has raised the possibility of a new class of leukemogenic genes. Individuals with AML-M5 usually have a poor prognosis associated with hyperleukocytosis and extramedul[[Unsupported Character - Codename & shy;]]lary involvement. Abnormalities in MLL, NPM1, FLT3 and NRAS have been reported in this disease. However, these genetic and/or epigenetic changes occur only in some of AML-M5 cases. AML subtypes are clonal hematopoietic diseases caused by somatic alterations of genomic information. Genome analysis on these distinct subtypes allows not only a better under[[Unsupported Character - Codename & shy;]]standing of leukemogenesis but also the identification of new biomarkers and/or drug targets. To gain new insight into leukemogenesis and the molecular basis underlying the clinical heterogeneity of AML-M5, we carried out exome sequencing and subsequent Sanger sequencing analysis in a large series of individuals with this leukemia. Recurrent somatic mutations of DNMT3A (encoding DNA methyltransferase 3A) were identified in 23 of 112 (20.5%) cases. Among the six different mutations affecting Arg478, Gly543, Arg882 and Val897 in our case series, those affecting Arg882 were the most frequent. DNMT3A mutations were present with NPM1 mutations in the same sample in 16 cases, whereas mutations of NPM1 did not overlap with MLL abnormalities. The DNMT3A mutants showed reduced enzymatic activity or aberrant affinity to histone H3 in vitro. We also carried out experiments to explore the possible epigenetic consequences of DNMT3A mutations. Indeed, gene expression pro[[Unsupported Character - Codename & shy;]]files and DNA methylation patterns showed some differences between patients with and without DNMT3A mutations. Notably, we found that members of HOXB genes were extensively upregulated at mRNA level in individuals with mutations of DNMT3A, and we detected hypomethylation of certain CpG islands in the HOXB locus. DNMT3A mutations enabled 32D cells to acquire growth and survival advantage even without growth factor. Leukemias with DNMT3A mutations constituted a group of poor prognosis with elderly disease onset and of promonocytic as well as monocytic predominance among AML-M5 individuals. These data suggest a contribution of aberrant DNA methyltransferase activity to the pathogenesis of acute monocytic leukemia and provides a useful new biomarker for relevant cases. The identification of genes whose expressions are specifically modulated by DNMT3A inactivation and the mechanism by which mutations in DNMT3A enable the pathogenesis of monocytic leukemia is on going. Genomic sequencing researches in AML and other malignancies have greatly facilitated identification of new oncogenic mutations. With the accumulation of more new data, decision making of risk-stratified therapy will be possible and should be integrated into the individualized treatment of AML. We performed the study to systemically investigate the frequencies and the prognostic relevance of previously known genetic events and newly established molecular markers in a large series of adult AML patients. In particular, we intent to stratify the “ambiguous” AML patients who lacked cytogenetic prognostic markers into appropriate prognostic groups by using these genetic markers. We examined the gene status for both fusion products such as AML1 (CBFα)-ETO, CBFß-MYH11, PML-RARα and MLL rearrangement and point mutations in genes including FLT3, C-KIT, N-RAS, NPM1, CEBPA, WT1, ASXL1, DNMT3A, MLL, IDH1, IDH2, and TET2 in 1,185 AML patients. Clinical analysis was mainly carried out among 605 cases without recognizable karyotype abnormalities except for 11q23. 452 out of these 605 patients (74.7%) were found to have at least 1 mutation, and the relationship of gene mutations with clinical outcome was investigated. Notably, we revealed 13 novel DNMT3A mutations, and a correlation pattern among NPM1, DNMT3A, FLT3, IDH1 and IDH2 mutations; CEBPA and TET2 mutations were discovered. Multivariate analysis identified DNMT3A and MLL mutations as independent factors predicting inferior overall survival (OS) and event free survival (EFS), while bi-allelic CEBPA mutations or NPM1 mutations without DNMT3A mutations conferred a better OS and EFS in whole group and younger patients aged less than 60 years. In summary, we have established a new stratification system with which to subclassify the prognosis of AML without cytogenetic prognostic factors according to the mutation patterns of 4 genes. Evaluation of molecular markers in AML, especially through detection of DNMT3A, MLL, NPM1, and CEBPA mutations, can therefore be recommended. Further studies will be focused on using different treatment strategies according to AML genotypes. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr SY38-01. doi:1538-7445.AM2012-SY38-01