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Amiloride, an old diuretic drug, is a potential therapeutic agent for multiple myeloma

ABSTRACT: The introduction of novel therapeutic agents has considerably improved the median survival of patients with multiple myeloma (MM). However, the natural history of the disease is characterized by continuous relapses over time. As a consequence, the development of new drugs is still required to treat MM recurrence. Here, we report for the first time the potent anti-myeloma activity of amiloride, an old potassium-sparing diuretic approved for the treatment of hypertension and edema due to heart failure. Amilorideinduced apoptosis was observed in a broad panel of MM cell lines and in xenograft mouse models. Moreover, amiloride also had a synergistic effect when combined with dexamethasone and melphalan. RNA-seq experiments showed that amiloride not only significantly altered the level of transcript isoforms and alternative splicing events, but also deregulated the spliceosomal machinery. Additionally, disruption of the splicing machinery in immunofluorescence studies was associated with the inhibition of myeloma cell viability after amiloride exposure. Although amiloride was able to induce apoptosis in myeloma cells lacking p53 expression, activation of p53 signaling was observed in wild-type and mutated TP53 cells after amiloride exposure. On the other hand, the manageable toxicity profile of amiloride is well known and we did not find a significant systemic toxicity in mice treated with amiloride. Overall, our results provide a mechanistic rationale for the use of amiloride as an alternative treatment option for relapsed MM patients.

ORGANISM(S): Homo sapiens

PROVIDER: GSE95077 | GEO | 2018/09/10

REPOSITORIES: GEO

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Project description:Screening small molecules and drugs for activity to modulate alternative splicing, we found that amiloride, distinct from four other intracellular pH-affecting analogues, could “normalize” the splicing of BCL-X, HIPK3 and RON/MISTR1 transcripts in human hepatocellular carcinoma Huh-7 cells. To elucidate the underlying mechanisms, our proteomic analyses of amiloride-treated cells detected hypo-phosphorylation of splicing factor SF2/ASF and also decreased levels of SRp20 and two un-identified SR proteins. We further observed decreased phosphorylation of AKT, ERK1/2 and PP1, while increased phosphorylation of p38 and JNK, suggesting that amiloride treatment down-regulated kinases and up-regulated phosphatases in the signal pathways known to affect the splicing factor protein phosphorylation. The amiloride effects of splicing factor protein hypo-phosphorylation and“normalized”oncogenic RNA splicing were both abrogated by pre-treatment with a PP1 inhibitor. We then performed global exon array analysis of Huh-7 cells treated with amiloride for 24 hours. Using gene array chips (Affymetrix GeneChip® Human Exon 1.0 ST Array of >518000 exons of 42974 genes) for exon array analysis (set parameters of correlation coefficient ≥ 0.7, splicing index ≤ -1.585 , and log2 ratio ≤ -1.585), we found that amiloride influenced the splicing patterns of 551 genes involving at least 584 exons, which included 495 known protein-coding genes involving 526 exons, many of which play key roles in functional networks of ion transport, extracellular matrix, cytoskeletons and genome maintenance. Cellular functional analyses revealed subsequent invasion and migration defects, cell cycle disruption, cytokinesis impairment, and lethal DNA degradation in amiloride-treated Huh-7 cells. This study thus provides mechanistic underpinnings for exploiting small molecule modulation of abnormal RNA splicing for cancer therapeutics. Target was prepared from 3 biological replicates of 0.5mM amiloride-treatment for 24hr and 3 control untreatment from Huh7 cell line and hybridized to the Affymetrix Human Exon 1.0 ST Array. The values of the hybridized probesets were normalized and analyzed for gene expression using dChip2010 software.

Project description:Background: Cancer cachexia (CAC) reduces patient survival and quality of life. Developments of efficient therapeutic strategies are required for the CAC treatments. This long-term process could be shortened by the drug-repositioning approach which exploits old drugs approved for non-cachexia disease. Amiloride, a diuretic drug, is clinically used for treatments of hypertension and edema due to heart failure. Here, we explored the effects of amiloride for ameliorating muscle wasting in murine models of cancer cachexia. Methods: CT26 and LLC tumor cells were subcutaneously injected into mice to induce cancer cachexia. Amiloride was intraperitoneally injected daily once tumors were formed. Cachexia features of the CT26 and LLC models, respectively, were characterized by phenotypic, histopathologic and biochemical analyses. Plasma exosomes and muscle atrophy-related proteins were quantitatively analyzed. Integrative NMR-based metabolomic and transcriptomic analyses were conducted to identify significantly altered metabolic pathways and distinctly changed metabolism-related biological processes in gastrocnemius. Results: The CT26 and LLC models displayed prominent cachexia features including decreases in body weight, skeletal muscle, adipose tissue and muscle strength. The amiloride treatment in tumor-bearing mice distinctly alleviated muscle atrophy and relieved cachexia-related features without affecting tumor growth. The CT26 and LLC cachexia mice showed increased particle density of plasma exosomes which were largely derived from tumors. Significantly, the amiloride treatment inhibited tumor-derived exosome release, which did not obviously affect exosome secretion from non-neoplastic tissues or induce observable systemic toxicities in normal healthy mice. Integrative-omics revealed significant metabolic impairments in cachectic gastrocnemius, including promoted muscular catabolism, inhibited muscular protein synthesis, blocked glycolysis and impeded ketone body oxidation. The amiloride treatment evidently improved the metabolic impairments in cachectic gastrocnemius. Conclusions: Our results demonstrated the efficacy of amiloride in ameliorating cachectic muscle wasting and elucidated the underlying mechanistic rationale for its use as an alternative strategy to improve CAC treatments.

Project description:Alternative splicing (AS) is a process that enables a mRNA to generate different protein isoforms that may have different biological functions or properties. Cancer cells often use this maneuverability to produce proteins that contribute to growth and survival. In previous study, we found that the antihypertensive drug amiloride has a novel biological function that regulates the AS on human cancer cells. However, it also showed that the effective concentration of amiloride in cancer treatment is too high to limit its use in future therapeutic application. In this study, we therefore used computational algorithms to predict the potential amiloride derivatives and found that BS008 is the most promising compound in all derivatives. The results demonstrated that BS008 can modulate the AS of apoptotic gene transcripts, including HIPK3, SMAC, and BCLX in cancer cells. Splicing regulatory involved a variety of histone modifications and splicing factors, and accompanied the changed of phosphorylation state of SR proteins during the splicing process. Inhibition of protein phosphatase-1 with okadaic acid pretreatment partially alleviated the effects of BS008 on the AS of HIPK3 and SMAC transcripts, as well as on the phosphorylation levels of SRSF3. RNA sequencing further discovered that the AS of many other apoptosis-related gene transcripts such as AATF, ATM, AIFM1, NFKB1, and API5 was modulated by BS008. We extended the study to apoptosis-associated molecules, and detected decreased levels of BCLX and increased levels of BAX and active CASPASE-3 in BS008-induced apoptosis. In vivo experiments indicated that the treatment of tumor-bearing mice with BS008 resulted in a marked decrease in tumor size. The combination BS008/sorafenib enhances anti-tumor activity of sorafenib and allows dose reduction of sorafenib without compromising its anti-tumor activity. In conclusion, these findings suggested that BS008, an amiloride derivative, may provide therapeutic potential for cancer treatment in future.

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Amiloride, an old diuretic drug, is a potential therapeutic agent for multiple myeloma

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