Alterations of RAS signalling in Chinese multiple myeloma patients: absent BRAF and rare RAS mutations, but frequent inactivation of RASSF1A by transcriptional silencing or expression of a non‐functional variant transcript

Ng, Margaret H.L.; Lau, Kin‐Mang; Wong, Wai Keung; To, Ka–Fai; Cheng, Suk‐Hang; Tsang, K. S.; Chan, Natalie Pui Ha; Kho, Bonnie; Lo, Kwok Wai; Tong, Joanna H.M.; Lam, Ching Wan; Chan, Jason

doi:10.1046/j.1365-2141.2003.04664.x

Cited by 23 publications

(15 citation statements)

References 30 publications

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“…The regulation of RASSF1 was confirmed by RT-PCR. The RASSF1 gene has been reported to be epigenetically regulated in many cancers, including multiple myeloma, thus demonstrating that its epigenetic regulation is an important factor in the development and maintenance of neoplasia (50,51).…”

Section: Table 6 Microarray and Reverse Transcription-pcr (Rt-pcr) Comentioning

confidence: 99%

Microarray Analysis of Epigenetic Silencing of Gene Expression in the KAS-6/1 Multiple Myeloma Cell Line

Pompéia¹,

Hodge²,

Plass

et al. 2004

Cancer Research

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The epigenetic control of gene transcription in cancer has been the theme of many recent studies and therapeutic approaches. Carcinogenesis is frequently associated with hypermethylation and consequent downregulation of genes that prevent cancer, e.g., those that control cell proliferation and apoptosis. We used the demethylating drug zebularine to induce changes in DNA methylation, then examined patterns of gene expression using cDNA array analysis and Restriction Landmark Genomic Scanning followed by RNase protection assay and reverse transcription-PCR to confirm the results. Microarray studies revealed that many genes were epigenetically regulated by methylation. We concluded that methylation decreased the expression of, or silenced, several genes, contributing to the growth and survival of multiple myeloma cells. For example, a number of genes (BAD, BAK, BIK, and BAX) involved in apoptosis were found to be suppressed by methylation. Sequenced methylation-regulated DNA fragments identified by Restriction Landmark Genomic Scanning were found to contain CpG islands, and some corresponded to promoters of genes that were regulated by methylation. We also observed that after the removal of the demethylating drug, the addition of interleukin 6 restored CpG methylation and re-established previously silenced gene patterns, thus implicating a novel role of interleukin 6 in processes regulating epigenetic gene repression and carcinogenesis.

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Section: Table 6 Microarray and Reverse Transcription-pcr (Rt-pcr) Comentioning

confidence: 99%

Microarray Analysis of Epigenetic Silencing of Gene Expression in the KAS-6/1 Multiple Myeloma Cell Line

Pompéia¹,

Hodge²,

Plass

et al. 2004

Cancer Research

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“…Costello et al (7) reported that, on average, 600 CpG islands are targets for methylation in malignant diseases. To date, f20 cancer-related genes have been identified that are frequently silenced by methylation in MM (5,8,9). Thus, identification of unknown epigenetically inactivated cancer-related genes in MM is of tremendous importance for a better understanding of the pathogenesis of this disease.…”

Section: Introductionmentioning

confidence: 99%

Genome-Wide Transcriptional Response to 5-Aza-2′-Deoxycytidine and Trichostatin A in Multiple Myeloma Cells

Heller¹,

Schmidt²,

Ziegler³

et al. 2008

Cancer Research

157

111

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To identify epigenetically silenced cancer-related genes and to determine molecular effects of 5-aza-2 ¶-deoxycytidine (AzadC) and/or trichostatin A (TSA) in multiple myeloma (MM), we analyzed global changes in gene expression profiles of three MM cell lines by microarray analysis. We identified up-regulation of several genes whose epigenetic silencing in MM is well known. However, much more importantly, we identified a large number of epigenetically inactivated cancerrelated genes that are involved in various physiologic processes and whose epigenetic regulation in MM was unknown thus far. In addition, drug treatment of MM cell lines resulted in down-regulation of several MM proliferationassociated factors (i.e., MAF, CCND1/2, MYC, FGFR3, MMSET). Ten Aza-dC and/or TSA up-regulated genes (CPEB1, CD9, GJA1, BCL7c, GADD45G, AKAP12, TFPI2, CCNA1, SPARC, and BNIP3) were selected for methylation analysis in six MM cell lines, 24 samples from patients with monoclonal gammopathy of undetermined significance (MGUS), and 111 samples from patients with MM. Methylation frequencies of these genes ranged between 0% and 17% in MGUS samples and between 5% and 50% in MM samples. Interestingly, methylation of SPARC and BNIP3 was statistically significantly associated with a poor overall survival of MM patients (P = 0.003 and P = 0.017, respectively). Moreover, SPARC methylation was associated with loss of SPARC protein expression by immunostaining in a subset of MM patients. In conclusion, we identified new targets for aberrant methylation in monoclonal gammopathies, and our results suggest that DNA methyltransferase and histone deacetylase inhibition might play an important role in the future treatment of patients with MM.

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“…Despite that RAS mutation occurs in 420% in myeloma, 1 few cases have been demonstrated to be associated with RAS activation by functional assay such as western blotting of phosphorylated ERK. Moreover, in contrast to conventional belief that ERK activation in myeloma is often caused by gain-of-function RAS mutation or RASSF1A methylation, 1,8 our case showed activating BRAF kinase V600E mutation instead, which has been shown to occur in about 2% of myeloma cases. 9 BRAF is a serine-threonine kinase, and a component of the RAS-RAF-MEK-ERK signaling pathway, which transmits mitogenic signals from activated cell surface growth factor receptors.…”

mentioning

confidence: 39%

Bortezomib/bendamustine/dexamethasone induced good PR in refractory relapse post auto-SCT with constitutive RAS activation due to V600E BRAF mutation

Chim

Wong

2014

Bone Marrow Transplant

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Despite recent major therapeutic advances in multiple myeloma, refractory disease relapse/progression, especially after auto-SCT, remains an unmet challenge in the field. Genetically, frequent RAS mutation has been reported in myeloma.1 Moreover, patients with NRAS mutation were associated with reduced sensitivity to bortezomib.2 Hence, targeted therapy against RAS activation is of interest. Sorafenib is a multi-kinase inhibitor targeting RAS activation.3 On the other hand, bortezomib has been shown to restore chemosensitivty to alkylators in refractory myeloma. 4 Herein, we report a bortezomib-and lenalidomide-refractory myeloma patient with ERK1/2 activation due to V600E BRAF mutation, in which sorafenib resulted in non-durable response, but subsequent bortezomib/bendamustine/dexamethasone (VBD) combination rendered a PR.A 57-year-old man presented with International Staging System stage II IgG kappa myeloma in April 2010 with rib fractures. He had primary refractory disease to VTD (bortezomib 1.3 mg/m 2 / dose once weekly, thalidomide 200 mg/day, dexamethasone 40 mg/week) and non-durable PR to RD (lenalidomide 25 mg/ day D1-D21, dexamethasone 20 mg/day D1-D4 and D8-D11) and VRD (bortezomib 1.3 mg/m 2 /dose D1, D4, D8 and D11, lenalidomide 25 mg/day D1-D21, dexamethasone 20 mg/day D1-D4 and D8-D11) (Figure 1). 5 Nonetheless, he achieved very good PR after auto-SCT using high-dose melphalan (200 mg/m 2 ), but disease progressed 9 months after auto-SCT. Moreover, disease became rapidly progressive in October 2012 despite arsenic trioxide 10 mg/day, dexamethasone 20 mg/day D1-D4 and D8-D11 (As 2 O 3 /dex) ( Figure 1). 6,7 Subsequent BM aspiration ( Figure 1) showed 60% plasma cells, with FISH showing amp(1q21) but absence of other high-risk features including del(17p), t(4;14) or t(14;16). Furthermore, western blot of CD138-sorted BM plasma cells showed constitutive ERK1/2 activation, consistent with constitutive activation of the RAS-RAF-MEK-ERK signaling pathway ( Figure 2). Genetic study of mutation hotspots of KRAS (codons 12, 13 and 61) and NRAS (codons 12, 13 and 61) reveal no mutation. Moreover, DNA methylation of the tumor suppressor gene RASSF1A (Ras association domain family protein-1 gene), localized to chromosome 3p21.3, was absent.8 However, V600E BRAF mutation resulting in substitution of valine by glutamate was demonstrated (Figure 2). Therefore, he was put on a trial of VSD (bortezomib 1.3 mg/m 2 /D1 and D4, sorafenib 200 mg b.i.d., dexamethasone 20 mg D1-D4 and D8-D11) with non-durable response, during which his IgG dropped from 7180 mg/dL to a nadir of 6340 mg/dL briefly (Figure 1). Despite further salvage with PAD (bortezomib 1.3 mg/m 2 /day D1, D4, D8 and D11, doxorubicin 9 mg/m 2 D1-D4, dexamethasone 20 mg/day D1-D4 and D8-D11), serum IgG escalated to 9100 mg/dL, when he was started on VBD (bortezomib 1.3 mg/m 2 /day D1 and D4, bendamustine 90 mg/m 2 /day D1 and D4, and dexamethasone 20 mg/day D1-D4), every 4 weeks. He achieved a PR after eight cycles of VBD with the latest serum IgG of 1820 ...

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Alterations of RAS signalling in Chinese multiple myeloma patients: absent BRAF and rare RAS mutations, but frequent inactivation of RASSF1A by transcriptional silencing or expression of a non‐functional variant transcript

Cited by 23 publications

References 30 publications

Microarray Analysis of Epigenetic Silencing of Gene Expression in the KAS-6/1 Multiple Myeloma Cell Line

Microarray Analysis of Epigenetic Silencing of Gene Expression in the KAS-6/1 Multiple Myeloma Cell Line

Genome-Wide Transcriptional Response to 5-Aza-2′-Deoxycytidine and Trichostatin A in Multiple Myeloma Cells

Bortezomib/bendamustine/dexamethasone induced good PR in refractory relapse post auto-SCT with constitutive RAS activation due to V600E BRAF mutation

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