Literature Review: DKC1 as a Robust Prognostic Factor and Potential Therapeutic Target in Multiple Myeloma

Literature Review: DKC1 as a Robust Prognostic Factor and Potential Therapeutic Target in Multiple Myeloma

1. Publication Overview

• Title: DKC1: a robust prognostic factor and potential therapeutic target in multiple myeloma

• Journal: Journal of Translational Medicine, 2026, 24:497 (latest IF = 9.7, JCR Q2 translational medicine journal, open access)

• DOI: 10.1186/s12967-026-07916-6

2. Core Conclusions

Pseudouridine synthase DKC1 is highly expressed in multiple myeloma (MM) and serves as an independent adverse prognostic marker for both overall survival (OS) and progression-free survival (PFS), refining the International Staging System (ISS) to enable more precise risk stratification. Cellular and animal experiments demonstrate that DKC1 promotes myeloma cell proliferation, suppresses apoptosis and drives tumour growth in vivo. Mechanistically, DKC1 performs site-specific pseudouridylation of ATF5 mRNA, increasing ATF mRNA stability and upregulating the anti-apoptotic protein Bcl-2, which drives disease progression. The DKC1 inhibitor pyrazofurin (PF) significantly suppresses myeloma activity in vitro and in vivo with minimal organ toxicity, establishing the DKC–ATF5 axis as a novel prognostic marker and therapeutic target in MM.

3. Role of Absin Products in the Study

The study used the Absin D-luciferin sodium salt (catalogue number abs42017259) as the substrate for in vivo bioluminescence imaging. Luciferase-expressing myeloma xenograft-bearing mice were labelled with this substrate, allowing the dynamic tumour burden in vivo to be quantified visually and objectively following PF intervention, and thereby providing quantitative visualisation of the in vivo pharmacodynamic data.

4. Background

Multiple myeloma is the second most common haematological malignancy, with global incidence rising by 167% between 1990 and 2021. The disease typically progresses from monoclonal gammopathy of undetermined significance (MGUS) through smouldering myeloma (SMM) to active MM, with plasma cell leukaemia (PCL) representing a highly aggressive subtype. Current therapeutic options include proteasome inhibitors, immunomodulatory agents, monoclonal antibodies, CAR-T therapy and autologous haematopoietic stem cell transplantation, but resistance and relapse remain unresolved and the disease is not curable.

The conventional ISS staging system stratifies patients using albumin and β2-microglobulin, but a substantial proportion of patients classified as low risk still relapse early, indicating the need for additional molecular markers. DKC1 encodes dyskerin, classically defined as a regulator of telomerase and of rRNA/snoRNA pseudouridylation, and acts as an oncogene in neuroblastoma, hepatocellular carcinoma and breast cancer while functioning as a tumour suppressor in pituitary and cutaneous squamous carcinoma, demonstrating tissue-dependent behaviour. Previous work had focused on DKC1-mediated ribosomal RNA modification, and the role of DKC1-dependent mRNA pseudouridylation in myeloma was entirely unknown. The present study is the first to characterise the clinical prognostic value of DKC1, its in vitro and in vivo function, and the underlying mRNA modification pathway in MM, closing a gap in this field.

5. Overall Study Design

The work follows a complete translational logic chain spanning eight levels: clinical bioinformatic mining, validation in clinical patient samples, in vitro cellular function (knockdown, overexpression and pharmacological intervention), in vivo xenograft pharmacology, transcriptome screening of downstream targets, mechanistic validation of mRNA pseudouridylation, and rescue experiments to confirm the pathway.

1. Multiple public datasets (MMRF CoMMpass, GEO) combined with clinical patient samples were used to verify the association between high DKC1 expression and advanced disease, relapse and poor survival; statistical models established DKC1 as an independent prognostic factor.

2. Cox regression, decision tree analysis and time-dependent ROC analysis demonstrated the ability of DKC1 to optimise ISS-based stratification.

3. Stable knockdown and overexpression myeloma cell lines (RPMI8226, MM.1S) were established, and EdU incorporation, soft agar colony formation, apoptosis and invasion assays defined the pro-tumour phenotype of DKC1.

4. In vitro dose-dependent suppression of proliferation by the DKC1 inhibitor PF was confirmed, with no detectable toxicity towards normal patient peripheral blood mononuclear cells.

5. In an NCG subcutaneous xenograft model, DKC1 knockdown cells and PF-treated animals were compared using bioluminescence imaging, tumour weight, and proliferation and apoptosis immunohistochemistry.

6. mRNA sequencing of DKC1-knockdown cells identified ATF5 as the key downstream target at the intersection of apoptosis and proliferation pathways.

7. RIP and carboxymethylated (CMC) single-base pseudouridylation sequencing demonstrated direct DKC1 binding to and modification of ATF5 mRNA, increasing its half-life.

8. Rescue experiments in which ATF5 was overexpressed in DKC1-knockdown cells and knocked down in DKC1-overexpressing cells established the DKC1–pseudouridylation–ATF5–Bcl-2 regulatory axis.

6. Module-by-Module Analysis

6.1 DKC1 expression, adverse clinical features and prognostic stratification

Logic: transcriptomic and proteomic analysis of public datasets and clinical samples, linked to survival statistics, establishes DKC1 as an independent prognostic factor and provides the basis for a DKC1-integrated staging system.

Core experiments: GEO/MMRF CoMMpass transcriptomic and proteomic analysis; Kaplan-Meier survival curves; univariate and multivariate Cox regression; nomogram and calibration curve; decision tree and time-dependent ROC; variable importance analysis.

Key results:

• DKC1 expression increased progressively across MGUS < MM < PCL; relapsed MM exceeded newly diagnosed MM; and ISS stage III exceeded stages I and II. DKC1 was significantly higher in MM patient bone marrow samples than in healthy donors.

• Kaplan-Meier curves showed significantly shortened OS and PFS in the DKC1-high group, and multivariate Cox analysis confirmed DKC1 as an independent risk factor for both OS and PFS.

• Incorporating DKC1 raised the C-index and lowered the integrated Brier score of the prognostic model. The decision tree stratified patients using DKC1 and β2-microglobulin, with 1-, 2- and 3-year AUC values of 0.77–0.79, and DKC1 carried greater variable importance than albumin and β2-microglobulin.

6.2 In vitro evidence that DKC1 promotes proliferation and suppresses apoptosis

Logic: three parallel arms — DKC1 knockdown (shDKC), DKC1 overexpression (oeDKC) and the small-molecule inhibitor PF — were compared across proliferation, clonogenicity, cell cycle, apoptosis and invasion readouts.

Core experiments: lentiviral stable transfection; EdU incorporation; soft agar colony formation; flow cytometric cell cycle and Annexin V apoptosis; Transwell invasion; western blotting for Bax and Bcl-2; dose-dependent PF treatment.

Key results:

• EdU-positive fractions and colony numbers fell sharply in shDKC cells and the proportion of S-phase cells decreased; oeDKC increased proliferation and colony-forming capacity; PF suppressed proliferation in a concentration-dependent manner.

• Spontaneous apoptosis increased significantly in shDKC cells, with pro-apoptotic Bax up-regulated and anti-apoptotic Bcl-2 down-regulated. Under nutrient deprivation, oeDKC markedly reduced apoptosis. PF at 0.2–0.8 µM induced apoptosis of MM cells in a dose-dependent manner without significant toxicity towards patient PBMCs.

• DKC1 knockdown inhibited invasion of myeloma cells, whereas overexpression enhanced it.

6.3 In vivo xenograft validation, including Absin product application

Logic: two mouse models were evaluated — xenografts bearing shDKC stable cells, and xenografts bearing luciferase-labelled cells receiving PF — with tumour growth, in vivo bioluminescence and histopathology readouts used to assess in vivo function.

Core experiments: NCG subcutaneous tumour establishment; serial monitoring of tumour volume and weight; in vivo bioluminescence imaging; Ki67 proliferation and TUNEL apoptosis immunohistochemistry; H&E staining of heart, liver and kidney for organ toxicity assessment.

Key results:

• Tumour volume and weight were significantly lower in shDKC animals than in controls, with reduced Ki67 positivity and increased TUNEL-positive cells.

• The in vivo bioluminescence signal of the PF group was markedly weaker than that of the vehicle control group, with slower tumour growth and lower tumour weight.

• H&E staining of heart, liver and kidney in PF-treated mice showed no obvious damage, with no difference in macrophage or neutrophil infiltration, indicating good in vivo safety.

Application of the Absin product: luciferase-expressing RPMI8226 cells were used to establish xenografts in mice. On days 7 and 11, mice received an intraperitoneal injection of 3 mg per mouse of Absin D-luciferin sodium salt (abs42017259), and after a short resting period bioluminescence signals were acquired with an IVIS imaging system to quantify overall tumour burden across groups.

6.4 Transcriptome screening identifies ATF5 as the downstream target

Logic: mRNA sequencing of DKC1-knockdown cells was used to identify differentially expressed genes common to apoptosis and proliferation pathways, with ATF5 selected as the key target and validated by bioinformatics, qPCR and western blotting.

Core experiments: RNA-seq differential expression analysis; GO and KEGG enrichment; MMRF cohort correlation analysis; RT-qPCR and western blotting for ATF5; mRNA half-life decay assay; RIP protein–RNA binding assay.

Key results:

• Seventy genes were shared between the apoptosis and proliferation enrichment sets, with ATF5 showing the largest down-regulation (log2FC = −3.46); DKC1 and ATF5 expression were significantly positively correlated (r = 0.17, P < 0.001).

• shDKC significantly reduced ATF5 mRNA and protein levels, oeDKC increased them, DKC1 knockdown markedly shortened the ATF5 mRNA half-life, and RIP confirmed direct binding of DKC1 protein to ATF5 mRNA.

6.5 ATF5 pseudouridylation and rescue validation

Logic: CMC-based chemistry locates pseudouridylation sites in ATF5 mRNA, and rescue experiments establish ATF5 as the mediator of every DKC1-dependent phenotype, completing the molecular axis.

Core experiments: CMC-qPCR; Mn²⁺-dependent reverse transcription single-base sequencing to locate Ψ sites; ATF5 overexpression rescue of shDKC and ATF5 knockdown reversal of oeDKC; EdU, colony formation and apoptosis rescue readouts; western blotting for Bcl-2 and Bax; pathway schematic.

Key results:

• Four DKC1-dependent pseudouridylation sites were identified in the ATF5 coding region, and modification was almost abolished after DKC1 knockdown. The loss of pseudouridylation directly reduced ATF5 mRNA stability.

• ATF5 overexpression partially restored the proliferation decline and apoptosis increase caused by DKC1 knockdown, while ATF5 knockdown reversed the pro-tumour phenotype of DKC1 overexpression.

• The mechanistic model is: DKC1 upregulation leads to increased ATF5 mRNA pseudouridylation, ATF5 protein accumulation, Bcl-2 upregulation, and consequently enhanced myeloma proliferation with suppressed apoptosis.

7. Overall Contribution of the Absin Product

1. Core substrate for quantitative in vivo pharmacodynamics. The in vivo imaging component of the study depended entirely on Absin D-luciferin sodium salt. Through the bioluminescent reaction with luciferase stably expressed in tumour cells, the luminescence intensity precisely and dynamically tracks tumour burden in vivo, allowing direct comparison of tumour growth between treated and control groups and providing non-invasive quantitative evidence of antitumour activity.

2. Linking in vitro phenotype to in vivo efficacy. In vitro proliferation and apoptosis assays reflect cellular effects only; in vivo imaging converts these cellular readouts into whole-animal tumour growth data, supporting the conclusion that PF is an effective DKC1 inhibitor in vivo, consistent with the quality-control standards expected of high-impact translational medicine journals.

3. Supporting translational argument for the target. Non-invasive imaging allows dynamic monitoring of long-term drug intervention effects; combined with organ pathology, it demonstrates that PF suppresses tumour growth without evident systemic toxicity, providing key in vivo visual evidence for DKC1 as a therapeutic target in MM and for the clinical potential of PF.

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