Abstract:RNA-binding proteins (RBPs) mainly contribute to abnormalities in posttranscriptional gene regulation. The RBP Musashi-2, an evolutionarily conserved protein, has been characterized as an oncoprotein in various tumors. However, the prognostic value and potential roles of Musashi-2 in clear cell renal cell carcinoma (ccRCC) have not yet been elucidated. In this study, we found that Musashi-2 was mainly expressed in the normal distal tubular cells and collecting duct cells of the kidneys, while its expression wa… Show more
“…4 E). These results provide further evidence that MSI2 can reprogram tumor metabolism, protein translation and immune infiltration [ 13 , 16 ]. Fig.…”
Section: Resultsmentioning
confidence: 64%
“…Our previous studies identified that MSI2 is involved in metabolic reprogramming-mediated immune infiltration in ccRCC [ 16 ] and immune dysregulation in DSS-induced colitis [ 17 ]. And recent study also confirmed that MSI2 can regulate immune-related signaling pathways in HCT116 and A549 cells, including TNF-α, inflammatory response and IFNG response pathway [ 13 ].…”
Section: Resultsmentioning
confidence: 99%
“…Currently, data describing the effects of MSI2 on immune function are scarce, but a few articles have confirmed that MSI2 contributes to the inflammatory process and immune response [ 11 – 13 , 16 , 17 ]. However, the regulation of HMGB1 by RBPs is still largely uncharacterized, as is tumor immunometabolism.…”
Section: Discussionmentioning
confidence: 99%
“…For H&E staining, sections were stained with hematoxylin and dehydrated in an alcohol gradient and xylene. IHC staining of proteins, including MSI2 (Abcam, #ab76148), CD3 (Servicebio, #GB11014), CD11c (Servicebio, #GB11059), CD11b (Servicebio, # GB11058), CD68 (Servicebio, # GB113150), Ly6g (Servicebio, # GB11229), P300 (Affinity, #AF5360) and HMGB1 (Abcam, #ab228624), was performed as described previously [ 16 ], and staining was analyzed by calculating the mean density per area using Image-Pro Plus. Histological analysis was performed to determine the inflammation score, which was defined as follows (modified from a previous report) [ 46 ].…”
Section: Human Pbmc Isolation Idc Induction and Coculturementioning
confidence: 99%
“…Regarding tumor metabolism, MSI2 could increase the translation and stability of targeted proteins to alter amino acid metabolism [ 14 ] and glycolipid metabolism processes [ 15 ]. Moreover, our previous studies have also identified the other unique roles of MSI2 in immunometabolism and post-translational modifications (PTMs); specifically, we observed that MSI2 positively regulated metabolic reprogramming and immune infiltration in renal clear cell carcinoma, which can be used to predict the sensitivity of targeted therapy and immunotherapy [ 16 ]. In addition, MSI2 knockout in type 3 (RORgt + ) innate lymphoid cells in mice attenuated dextran sodium sulfate (DSS)-induced colitis pathophysiology [ 17 ], and USP10 could interact with and stabilize MSI2 through Lys48-linked deubiquitination to prevent its degradation in CRC [ 18 ], also MSI2 knockdown could trigger CRC cell ferroptosis progression [ 19 ].…”
Post-translational modifications (PTMs) of the non-histone protein high-mobility group protein B1 (HMGB1) are involved in modulating inflammation and immune responses. Recent studies have implicated that the RNA-binding protein (RBP) Musashi-2 (MSI2) regulates multiple critical biological metabolic and immunoregulatory functions. However, the precise role of MSI2 in regulating PTMs and tumor immunity in colorectal cancer (CRC) remains unclear. Here, we present data indicating that MSI2 potentiates CRC immunopathology in colitis-associated colon cancer (CAC) mouse models, cell lines and clinical specimens, specifically via HMGB1-mediated dendritic cell (DC) maturation and migration, further contributes to the infiltration of CD4+ and CD8+ T cells and inflammatory responses. Under stress conditions, MSI2 can exacerbate the production, nucleocytoplasmic transport and extracellular release of damage-associated molecular patterns (DAMPs)-HMGB1 in CRC cells. Mechanistically, MSI2 mainly enhances the disulfide HMGB1 production and protein translation via direct binding to nucleotides 1403–1409 in the HMGB1 3′ UTR, and interacts with the cytoplasmic acetyltransferase P300 to upregulate its expression, further promoting the acetylation of K29 residue in HMGB1, thus leading to K29-HMGB1 nucleocytoplasmic translocation and extracellular release. Furthermore, blocking HMGB1 activity with glycyrrhizic acid (Gly) attenuates MSI2-mediated immunopathology and immune infiltration in CRC in vitro and in vivo. Collectively, this study suggests that MSI2 may improve the prognosis of CRC patients by reprogramming the tumor immune microenvironment (TIME) through HMGB1-mediated PTMs, which might be a novel therapeutic option for CRC immunotherapy.
“…4 E). These results provide further evidence that MSI2 can reprogram tumor metabolism, protein translation and immune infiltration [ 13 , 16 ]. Fig.…”
Section: Resultsmentioning
confidence: 64%
“…Our previous studies identified that MSI2 is involved in metabolic reprogramming-mediated immune infiltration in ccRCC [ 16 ] and immune dysregulation in DSS-induced colitis [ 17 ]. And recent study also confirmed that MSI2 can regulate immune-related signaling pathways in HCT116 and A549 cells, including TNF-α, inflammatory response and IFNG response pathway [ 13 ].…”
Section: Resultsmentioning
confidence: 99%
“…Currently, data describing the effects of MSI2 on immune function are scarce, but a few articles have confirmed that MSI2 contributes to the inflammatory process and immune response [ 11 – 13 , 16 , 17 ]. However, the regulation of HMGB1 by RBPs is still largely uncharacterized, as is tumor immunometabolism.…”
Section: Discussionmentioning
confidence: 99%
“…For H&E staining, sections were stained with hematoxylin and dehydrated in an alcohol gradient and xylene. IHC staining of proteins, including MSI2 (Abcam, #ab76148), CD3 (Servicebio, #GB11014), CD11c (Servicebio, #GB11059), CD11b (Servicebio, # GB11058), CD68 (Servicebio, # GB113150), Ly6g (Servicebio, # GB11229), P300 (Affinity, #AF5360) and HMGB1 (Abcam, #ab228624), was performed as described previously [ 16 ], and staining was analyzed by calculating the mean density per area using Image-Pro Plus. Histological analysis was performed to determine the inflammation score, which was defined as follows (modified from a previous report) [ 46 ].…”
Section: Human Pbmc Isolation Idc Induction and Coculturementioning
confidence: 99%
“…Regarding tumor metabolism, MSI2 could increase the translation and stability of targeted proteins to alter amino acid metabolism [ 14 ] and glycolipid metabolism processes [ 15 ]. Moreover, our previous studies have also identified the other unique roles of MSI2 in immunometabolism and post-translational modifications (PTMs); specifically, we observed that MSI2 positively regulated metabolic reprogramming and immune infiltration in renal clear cell carcinoma, which can be used to predict the sensitivity of targeted therapy and immunotherapy [ 16 ]. In addition, MSI2 knockout in type 3 (RORgt + ) innate lymphoid cells in mice attenuated dextran sodium sulfate (DSS)-induced colitis pathophysiology [ 17 ], and USP10 could interact with and stabilize MSI2 through Lys48-linked deubiquitination to prevent its degradation in CRC [ 18 ], also MSI2 knockdown could trigger CRC cell ferroptosis progression [ 19 ].…”
Post-translational modifications (PTMs) of the non-histone protein high-mobility group protein B1 (HMGB1) are involved in modulating inflammation and immune responses. Recent studies have implicated that the RNA-binding protein (RBP) Musashi-2 (MSI2) regulates multiple critical biological metabolic and immunoregulatory functions. However, the precise role of MSI2 in regulating PTMs and tumor immunity in colorectal cancer (CRC) remains unclear. Here, we present data indicating that MSI2 potentiates CRC immunopathology in colitis-associated colon cancer (CAC) mouse models, cell lines and clinical specimens, specifically via HMGB1-mediated dendritic cell (DC) maturation and migration, further contributes to the infiltration of CD4+ and CD8+ T cells and inflammatory responses. Under stress conditions, MSI2 can exacerbate the production, nucleocytoplasmic transport and extracellular release of damage-associated molecular patterns (DAMPs)-HMGB1 in CRC cells. Mechanistically, MSI2 mainly enhances the disulfide HMGB1 production and protein translation via direct binding to nucleotides 1403–1409 in the HMGB1 3′ UTR, and interacts with the cytoplasmic acetyltransferase P300 to upregulate its expression, further promoting the acetylation of K29 residue in HMGB1, thus leading to K29-HMGB1 nucleocytoplasmic translocation and extracellular release. Furthermore, blocking HMGB1 activity with glycyrrhizic acid (Gly) attenuates MSI2-mediated immunopathology and immune infiltration in CRC in vitro and in vivo. Collectively, this study suggests that MSI2 may improve the prognosis of CRC patients by reprogramming the tumor immune microenvironment (TIME) through HMGB1-mediated PTMs, which might be a novel therapeutic option for CRC immunotherapy.
Background
Musashi-2 (MSI2) is a critical RNA-binding protein (RBP) whose ectopic expression drives the pathogenesis of various cancers. Accumulating evidence suggests that inducing ferroptosis of tumor cells can inhibit their malignant biological behavior as a promising therapeutic approach. However, it is unclear whether MSI2 regulates cell death in colorectal cancer (CRC), especially the underlying mechanisms and biological effects in CRC ferroptosis remain elusive.
Methods
Experimental methods including qRT‒PCR, immunofluorescence, flow cytometry, western blot, co-immunoprecipitation, CCK-8, colony formation assay, in vitro cell transwell migration and invasion assays, in vivo xenograft tumor experiments, liver and lung CRC metastasis models, CAC mice models, transmission electron microscopy, immunohistochemistry, histopathology, 4D label-free proteomics sequencing, bioinformatic and database analysis were used in this study.
Results
Here, we investigated that MSI2 was upregulated in CRC and positively correlated with ferroptosis inhibitor molecules. MSI2 deficiency suppressed CRC malignancy by inhibiting cell proliferation, viability, migration and invasion in vitro and in vivo; and MSI2 deficiency triggered CRC ferroptosis by changing the intracellular redox state (ROS levels and lipid peroxidation), erastin induced cell mortality and viability, iron homeostasis (intracellular total irons and ferrous irons), reduced glutathione (GSH) levels and mitochondrial injury. Mechanistically, through 4D-lable free proteomics analysis on SW620 stable cell lines, we demonstrated that MSI2 directly interacted with p-ERK and MSI2 knockdown downregulated the p-ERK/p38/MAPK axis signaling pathway, which further repressed MAPKAPK2 and HPSB1 phosphorylation, leading to decreased expression of PCNA and Ki67 and increased expression of ACSL4 in cancer cells. Furthermore, HSPB1 could rescue the phenotypes of MSI2 deficiency on CRC ferroptosis in vitro and in vivo.
Conclusions
This study indicates that MSI2 deficiency suppresses the growth and survival of CRC cells and promotes ferroptosis by inactivating the MAPK signaling pathway to inhibit HSPB1 phosphorylation, which leads to downregulation of PCNA and Ki67 and upregulation of ACSL4 in cancer cells and subsequently induces redox imbalance, iron accumulation and mitochondrial shrinkage, ultimately triggering ferroptosis. Therefore, targeted inhibition of MSI2/MAPK/HSPB1 axis to promote ferroptosis might be a potential treatment strategy for CRC.
The advent of PD1/PD-L1 inhibitors has significantly transformed the therapeutic landscape for clear cell renal cell carcinoma (ccRCC). This review provides an in-depth analysis of the biological functions and regulatory mechanisms of PD1 and PD-L1 in ccRCC, emphasizing their role in tumor immune evasion. We comprehensively evaluate the clinical efficacy and safety profiles of PD1/PD-L1 inhibitors, such as Nivolumab and Pembrolizumab, through a critical examination of recent clinical trial data. Furthermore, we discuss the challenges posed by resistance mechanisms to these therapies and potential strategies to overcome them. We also explores the synergistic potential of combination therapies, integrating PD1/PD-L1 inhibitors with other immunotherapies, targeted therapies, and conventional modalities such as chemotherapy and radiotherapy. In addition, we examine emerging predictive biomarkers for response to PD1/PD-L1 blockade and biomarkers indicative of resistance, providing a foundation for personalized therapeutic approaches. Finally, we outline future research directions, highlighting the need for novel therapeutic strategies, deeper mechanistic insights, and the development of individualized treatment regimens. Our work summarizes the latest knowledge and progress in this field, aiming to provide a valuable reference for improving clinical efficacy and guiding future research on the application of PD1/PD-L1 inhibitors in ccRCC.
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