A novel indirubin- 3-monoxime derivative I3MV- 8b exhibits remarkable cytotoxicity against multiple myeloma by targeting TRIM28
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Published on: May 4, 2017
Teng Fang1, Lanting Liu1, Hao Sun1
1State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300020, China.
Introduction:
Maintaining protein homeostasis is vital for multiple myeloma (MM) cell survival. Indirubin- 3-monoxime (I3MO), a potential MM therapeutic, inhibits proteasome activity, while histone deacetylase 6 (HDAC6) regulates autophagy. We developed I3MV- 8b, an I3MO derivative, integrating an HDAC6 inhibitor moiety to enhance dual inhibition of proteasome and autophagy pathways.
Methods:
The anti-MM effects of I3MV- 8b were tested in vitro and in vivo. To identify downstream targets, RNA-seq and dual-luciferase reporter assays were performed. Additionally, ChIP-seq and IP-MS techniques were employed to elucidate the underlying molecular mechanism.
Results:
I3MV- 8b significantly suppressed MM cell proliferation and induced apoptosis. Combined with proteasome inhibitors, I3MV- 8b enhanced cytotoxicity by concurrently inhibiting proteasome and autophagy pathways. It reduced TRIM28 transcription, correlating with lower expression of proteasome subunits and autophagy-related genes. ChIP-seq revealed that TRIM28 binds to proteasome gene promoters, and its knockdown decreased proteasome subunit expression and activity. TRIM28 knockdown also impaired autophagosome formation. IP-MS and Co-IP assays showed TRIM28 interacted with 14-3 - 3ζ, a negative regulator of autophagy, promoting its ubiquitination and degradation. This interaction reduced autophagy regulation, further sensitizing cells to treatment.
Conclusions:
I3MV- 8b offers a novel dual inhibition strategy targeting proteasome and autophagy, presenting a promising therapeutic option for MM.
Insights
A novel drug, I3MV-8b, effectively targets both proteasome and autophagy pathways in multiple myeloma (MM). This dual inhibition strategy shows promise for enhancing MM treatment by suppressing cancer cell growth and inducing apoptosis.
Area of Science:
- Oncology
- Molecular Biology
- Pharmacology
Background:
- Protein homeostasis is crucial for multiple myeloma (MM) cell survival.
- Indirubin-3-monoxime (I3MO) is a potential MM therapeutic that inhibits proteasome activity.
- Histone deacetylase 6 (HDAC6) regulates autophagy, a key cellular process.
Purpose of the Study:
- To develop and evaluate I3MV-8b, a novel derivative of I3MO with integrated HDAC6 inhibition.
- To investigate the dual inhibition of proteasome and autophagy pathways by I3MV-8b in MM.
- To elucidate the molecular mechanisms underlying I3MV-8b's anti-MM effects.
Main Methods:
- In vitro and in vivo testing of I3MV-8b's anti-MM effects.
- RNA-sequencing (RNA-seq) and dual-luciferase reporter assays to identify downstream targets.
- Chromatin immunoprecipitation sequencing (ChIP-seq) and immunoprecipitation-mass spectrometry (IP-MS) to determine molecular mechanisms.
Main Results:
- I3MV-8b significantly suppressed MM cell proliferation and induced apoptosis.
- Combined treatment with proteasome inhibitors enhanced I3MV-8b's cytotoxicity.
- I3MV-8b reduced TRIM28 transcription, impacting proteasome and autophagy gene expression and impairing autophagosome formation.
Conclusions:
- I3MV-8b represents a novel dual inhibition strategy for targeting proteasome and autophagy in MM.
- The drug demonstrated promising therapeutic potential for MM treatment.
- I3MV-8b's mechanism involves TRIM28 regulation and interaction with 14-3-3ζ, enhancing MM cell sensitization.
