Frequency of KRAS mutations in adult Korean patients with acute myeloid leukemia

Analysis of RAS gene mutations in cytogenetically normal de novo acute myeloid leukemia patients reveals some novel alterations

Rat sarcoma gene (RAS) holds great importance in pathogenesis of acute myeloid leukemia (AML). The activated mutations in Neuroblastoma rat sarcoma viral oncogene homolog (NRAS) and Kirsten rat sarcoma viral oncogene homolog (KRAS) confers proliferative and survival signals, deliberating numerous effects on overall survival and progression free survival in AML patients. In this study thirty one (31) blood samples of adult newly diagnosed AML patients were collected to identify possible incidence of mutations through amplification of KRAS (exon 1 and 2) and NRAS gene (exon 1 and 2) using polymerase chain reaction (PCR). Amplicons were then subjected to sequencing and were analyzed through Geneious Prime 2019. Five of thirty one (16.12%) patients had altered sites in either NRAS or KRAS. The NRAS mutations were observed in three AML patients (N = 3, 9.67%). A novel missense mutation NRAS-I36R (239 T > G) representing a substitution of single nucleotide basepair found in NRAS exon 1 while exon 2 was detected with heterozygous mutation NRAS-E63X (318G > T) and insertion (A), resulting in frameshift of the amino acid sequence and insertion of two nucleotide basepairs (TA) in two of the patients. KRAS mutations (N = 2, 6.45%) were found in exon 1 whereas no mutations in KRAS exon 2 were detected in our patient cohort. Mutation in KRAS Exon 1, KRAS-D30N (280G > A) was observed in two patients and one of them also had a novel heterozygous mutation KRAS-L16N (240G > C). In addition there was no statistically significant association of mutRAS gene of AML patients with several prognostic markers including age, gender, karyotyping, CD34 positivity, cytogenetic abnormalities, total leukocyte count, white blood cell count and French-American-British (FAB) classification. However, the presence of mutRAS gene were strongly associated (p = 0.001) with increased percentage of bone marrow blasts. The prevalence of mutations in correlation with clinical and hematological parameter is useful for risk stratification in AML patients.

Asia-inclusive global development of pevonedistat: Clinical pharmacology and translational research enabling a phase 3 multiregional clinical trial

Abstract

The investigational NEDD8‐activating enzyme inhibitor pevonedistat is being evaluated in combination with azacitidine versus single‐agent azacitidine in patients with higher‐risk myelodysplastic syndrome (higher‐risk MDS), higher‐risk chronic myelomonocytic leukemia (higher‐risk CMML), or low‐blast acute myeloid leukemia (AML) in a Phase 3 trial PANTHER. To support Asia‐inclusive global development, we applied multiregional clinical trial (MRCT) principles of the International Conference on Harmonisation E17 guidelines by evaluating similarity in drug‐related and disease‐related intrinsic and extrinsic factors. A PubMed literature review (January 2000–November 2019) supported similarity in epidemiology of higher‐risk MDS, AML, and CMML in Western and East Asian populations. Furthermore, the treatment of MDS/AML was similar in both East Asian and Western regions, with the same dose of azacitidine being the standard of care. Median overall survival in MDS following azacitidine treatment was generally comparable across regions, and the types and frequencies of molecular alterations in AML and MDS were comparable. Dose‐escalation studies established the same maximum tolerated dose of pevonedistat in combination with azacitidine in Western and East Asian populations. Pevonedistat clearance was similar across races. Taken together, conservation of drug‐related and disease‐related intrinsic and extrinsic factors supported design of an Asia‐inclusive Phase 3 trial and a pooled East Asian region. A sample size of ~ 30 East Asian patients (of ~ 450 randomized) was estimated as needed to demonstrate consistency in efficacy relative to the global population. This analysis is presented as an exemplar to illustrate application of clinical pharmacology and translational science principles in designing Asia‐inclusive MRCTs.

Small Molecule KRAS Agonist for Mutant KRAS Cancer Therapy

Background

Lung cancer patients with KRAS mutation(s) have a poor prognosis due in part to the development of resistance to currently available therapeutic interventions. Development of a new class of anticancer agents that directly targets KRAS may provide a more attractive option for the treatment of KRAS-mutant lung cancer.

Results

Here we identified a small molecule KRAS agonist, KRA-533, that binds the GTP/GDP-binding pocket of KRAS. In vitro GDP/GTP exchange assay reveals that KRA-533 activates KRAS by preventing the cleavage of GTP into GDP, leading to the accumulation of GTP-KRAS, an active form of KRAS. Treatment of human lung cancer cells with KRA-533 resulted in increased KRAS activity and suppression of cell growth. Lung cancer cell lines with KRAS mutation were relatively more sensitive to KRA-533 than cell lines without KRAS mutation. Mutating one of the hydrogen-bonds among the KRA-533 binding amino acids in KRAS (mutant K117A) resulted in failure of KRAS to bind KRA-533. KRA-533 had no effect on the activity of K117A mutant KRAS, suggesting that KRA-533 binding to K117 is required for KRA-533 to enhance KRAS activity. Intriguingly, KRA-533-mediated KRAS activation not only promoted apoptosis but also autophagic cell death. In mutant KRAS lung cancer xenografts and genetically engineered mutant KRAS-driven lung cancer models, KRA-533 suppressed malignant growth without significant toxicity to normal tissues.

Conclusions

The development of this KRAS agonist as a new class of anticancer drug offers a potentially effective strategy for the treatment of lung cancer with KRAS mutation and/or mutant KRAS-driven lung cancer.

Electronic supplementary material

The online version of this article (10.1186/s12943-019-1012-4) contains supplementary material, which is available to authorized users.

RAS mutations in acute myeloid leukaemia patients: A review and meta-analysis

RAS oncogene mutations frequently occur in acute myeloid leukaemia (AML), but the prognostic significance of RAS mutations in AML is inconclusive. We searched the databases of PubMed, Web of Science, EMBASE, and Cochrane from 1990 to 2018. In this study, 24 eligible studies were included, and the meta-analysis was conducted with the Comprehensive Meta-Analysis Version 2 software program. The row hazard ratio (HR) was adjusted and re-evaluated when publication bias existed after detecting all the heterogeneities. A combined analysis showed that RAS mutations were not associated with a poor prognosis in general AML patients (HR: 0.96, 95% CI: 0.78-1.19, p = 0.70). To further verify the results, a subgroup analysis was conducted. Interestingly, in the analysis of age bracket, children with RAS mutations had an unfavourable survival (HR: 1.35, 95% CI: 1.05-1.75, p = 0.02) of AML, but the adults did not (HR: 0.87, 95% CI: 0.70-1.09, p = 0.21). Further analysis of the subgroup of children indicated that patients with NRAS mutations had an adverse prognosis (HR: 1.55, 95% CI: 1.13-2.12, p = 0.007), but not those with KRAS mutations (HR: 1.51, 95% CI: 0.34-6.73, p = 0.59). In conclusion, this study revealed that RAS mutations did not influence the over survival for adults with AML. However, NRAS mutations may be a key prognostic marker related with poor survival for children with AML.