PTα enhances mRNA translation and potentiates CAR T cells for solid tumor eradication.

Chimeric antigen receptor (CAR) therapy has been proved effective in a stream of clinical trials, especially in hematologic malignancies. However, current CAR therapy is highly personalized as cells used are derived from patients themselves, which can be costly, time-consuming, and sometimes fails to achieve optimal therapeutic results due to poor quality/quantity of patient-derived cells. On the contrary, universal CAR therapy, which is based on healthy individuals’ cells, circumvents several limitations of current autologous CAR therapy. To achieve the universality of CAR therapy, the allogeneic cell transplantation related issues, such as graft-versus-host disease (GVHD) and host-versus-graft activities (HVGA), must be addressed. In this review, we focus on current progress regarding GVHD and HVGA in the universal CAR therapy, followed by a universal CAR design that may be applied to allogeneic cells and a summary of key clinical trials in this field. This review may provide valuable insights into the future design of universal CAR products.

The Y-box binding protein 1 (YB-1) is a member of the cold shock domain (CSD) protein family and is recognized as an oncogenic factor in several solid tumors. By binding to RNA, YB-1 participates in several steps of posttranscriptional regulation of gene expression, including mRNA splicing, stability, and translation; microRNA processing; and stress granule assembly. However, the mechanisms in YB-1-mediated regulation of RNAs are unclear. Previously, we used both systematic evolution of ligands by exponential enrichment (SELEX) and individual-nucleotide resolution UV cross-linking and immunoprecipitation coupled RNA-Seq (iCLIP-Seq) analyses, which defined the RNA-binding consensus sequence of YB-1 as CA(U/C)C. We also reported that through binding to its core motif CAUC in primary transcripts, YB-1 regulates the alternative splicing of a CD44 variable exon and the biogenesis of miR-29b-2 during both Drosha and Dicer steps. To elucidate the molecular basis of the YB-1-RNA interactions, we report high-resolution crystal structures of the YB-1 CSD in complex with different RNA oligos at 1.7 Å resolution. The structure revealed that CSD interacts with RNA mainly through π-π stacking interactions assembled by four highly conserved aromatic residues. Interestingly, YB-1 CSD forms a homodimer in solution, and we observed that two residues, Tyr-99 and Asp-105, at the dimer interface are important for YB-1 CSD dimerization. Substituting these two residues with Ala reduced CSD's RNA-binding activity and abrogated the splicing activation of YB-1 targets. The YB-1 CSD-RNA structures presented here at atomic resolution provide mechanistic insights into gene expression regulated by CSD-containing proteins.

Background: RNA-binding proteins (RBPs) play essential roles in post-transcriptional control of gene expression. Dysregulation of RBPs is intensively implicated in development and progression of human diseases, including cancers. However, the roles of RBPs in nasopharyngeal carcinoma (NPC), which is a distinct subtype of head and neck cancer, remain elusive.Methods: NPC-related RBPs were explored by analyzing GEO database and high-throughput proteomic data obtained from crosslinking immunoprecipitation. The expression levels of Y box binding protein 1 (YBX1) protein in NPC samples were measured by immunohistochemistry (IHC) staining. The association of YBX1 protein levels with prognosis of NPC patients was analyzed by Kaplan-Meier Plotter. The expression levels of YBX1 in NPC cells were inhibited by RNA interference. Cell growth was measured by CCK-8 assay. Cell mobility and invasiveness were measured by transwell assays. Tumorigenicity was measured by using a xenograft tumor assay. The expression levels of mRNAs or proteins were determined by qPCR or western blot assays, respectively. The mRNAs binding to YBX1 were determined by RNA immunoprecipitation (RIP) and qPCR. The effect of YBX1 on mRNA translation was measured by luciferase reporter assay.Results: In the present study, we demonstrated a differentially expressed RBPs profile between NPC and its normal counterpart. Among these aberrantly expressed RBPs, YBX1 was overexpressed in NPC. We found that YBX1 is mainly localized in the cytoplasm of NPC cells. Loss of YBX1 led to reduced cell proliferation, migration and invasiveness in vitro, and reduced tumorigenicity in vivo. Overexpression of YBX1 associates with high expression of cell cycle G2/M checkpoint modulators. In addition, YBX1 promotes AURKA protein expression by directly binding to its mRNA. Loss of YBX1 leads to reduction of AURKA protein level. Forced expression of AURKA rescues cell proliferation and invasiveness in YBX1-silenced NPC cell.Conclusions: The current study indicated that YBX1 promotes NPC cell proliferation and invasiveness through enhancing protein synthesis of AURKA.

Y-box binding protein 1 (YB-1) functions as a translational regulator and has been suggested to elevate MYC mRNA translation via an internal ribosome entry segment (IRES) point mutation in multiple myeloma (MM). We show that YB-1-mediated translation of MYC mRNA occurs independently of the reported IRES mutation, as 87 MM patients (n=88) and all tested human MM cell lines (HMCLs) were negative for the mutation. We show for the first time that positive MYC staining predicts YB-1 co-expression in malignant plasma cells and YB-1/MYC co-expression increases from 30% in medullary to 70% in extramedullary MM. YB-1 knockdown in HMCLs reduced both MYC protein levels and MYC mRNA in the polysomal fraction, providing a mechanism by which YB-1 controls MYC translation. MYC transcription of YB-1 is demonstrated in HMCLs as MYC knockdown resulted in reduced YB-1 protein and mRNA levels. Furthermore, MYC activation in non-malignant mouse embryonic fibroblasts (MEFs) increased YB-1 mRNA, clearly indicating that MYC drives YB-1 transcription. Importantly, perturbation of the MYC/YB-1 oncogenic circuit leads to apoptosis in HMCLs. Here, we demonstrate that these two proteins co-regulate each other via combined transcriptional/translational activity establishing their pivotal role in MM cell survival. We therefore suggest that targeting the YB-1/mRNA interaction provides a new strategy for MM drug development.

Engineered T and NK cell therapies have widely been used to treat hematologic malignancies and solid tumors, with promising clinical results. Current chimeric antigen receptor (CAR) T cell therapeutics have, however, been associated with treatment-related adverse events such as cytokine release syndrome (CRS) and are prone to immunologic exhaustion. CAR-NK therapeutics, while not associated with CRS, have limited in vivo persistence. We now demonstrate that an NK-like TCRαβ + CD8 T cell subset, identified and expanded ex vivo through its expression of the activating receptor NKG2C (NKG2C + NK-like T cells), can be transduced to express a second-generation CD19 CAR (1928z), resulting in superior tumor clearance, longer persistence and decreased exhaustion compared to conventional 1928z CAR + CD8 T cells and 1928z CAR+ NK cells. Moreover, CAR-modified NKG2C + NK-like T cells resulted in significantly reduced CRS compared to conventional CAR + CD8 T cells. Similarly, NKG2C + NK-like T cells engineered with a TCR targeting the NY-ESO-1 antigen exhibit robust tumor control and minimal exhaustion compared to TCR-engineered conventional CD8 T cells. These data establish NKG2C + NK-like T cells as a robust platform for cell engineering, and offer a safer, more durable alternative to conventional CAR-T and CAR-NK therapies.

Epithelial ovarian cancer (EOC) is a disease responsible for more cancer deaths among women in the Western world than all other gynecologic malignancies and breast cancer is leading cause of cancer death among the women worldwide. A major problem with such cancers is chemoresistance; hence the need to identify predictive biomarkers. Interestingly, overexpression of YB-1 in ovarian and breast cancer cells induces cisplatin resistance. Platinum coumpounds like cisplatin is often used in the treatments of these cancers. Y box-binding protein 1 (YB-1) is a multifunctional protein that affects transcription, splicing and translation of mRNA. In this study, we used a tagged YB-1 construct to identify by mass spectrometry the proteins that interacted with YB-1 and required for cisplatin resistance. Using the combination of two bioinformatics databases (Oncomine public microarray and genomic hybridization), we focused on the YB-1 protein partners that are potentially involved in cancer progression. We used the siRNA technique to screen different partners of YB-1 that are directly involve in the cisplatin resistance of MCF7 and MDA-MB-231 cells lines. From this analysis, we found that the RPS4X protein, a new partner of YB-1, would be a good marker of cisplatin resistance in breast cancer patients. Interestingly, the YB-1/RPS4X complex was also found in ovarian cancer cells. Like in the breast cancer cell lines, the depletion of RPS4X protein induced the cisplatin resistance of ovarian cancer cells lines (SKOV3 and OVCAR3). Finally, we used a validate antibodies to assess by immunohistochemistry the protein levels of RPS4X and YB-1 in tumor tissue samples from 192 high-grade serous epithelial ovarian cancer patients. We found that RPS4X correlated significantly with ovarian cancer patient outcome. Taken together, these results suggest that, the YB-1/RPS4X complex is a significant potential target to counteract cisplatin resistance in breast and ovarian cancers. Also, we have established that RPS4X is a new promising prognostic marker for patients with high-grade ovarian cancer. More importantly, RPS4X is shown to be predictive of cisplatin response. Additional immunohistochemistry studies on low-grade ovarian cancers and breast cancers are required to confirm the predictive value of RPS4X. Citation Format: Serges P. Tsofack, Liliane Meunier, Anne-Marie Mes-Masson, Michel Lebel. RPS4X, a new prognostic and predictive biomarker of ovarian and breast cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2864. doi:10.1158/1538-7445.AM2014-2864

The Y-Box Binding protein 1 (YB-1) is a 324 amino acid-long member of the Cold Shock Domain (CSD) protein superfamily. YB-1 interacts with micro RNAs and non-coding RNAs in the cytoplasm, acting as a regulator of mRNA translation. YB-1 translocation into the nucleus is circadian clock-dependent and leads to the upregulation of cyclin gene expression, among others. Another mechanism of nuclear translocation of YB-1 is mediated by phosphorylation of the Ser 102 residue in the CSD. The YB-1 oncoprotein acts as a transcription factor when bound to DNA, modulating the transcription of genes that regulate biological processes such as Multidrug Resistance Mutation 1 (MDR1). YB-1 is linked to poor prognosis in breast, prostate, and liver cancer. Despite advances in biomedicine, the incidence and mortality of hepatocellular carcinoma (HCC) remain high. Sorafenib, a tyrosine kinase Inhibitor (TKI), is the first-line treatment for advanced HCC. Sorafenib also inhibits downstream activation of NF-kB by inhibition of Lyn phosphorylation (Y397). However, it was observed in many patients that its sorafenib’s effectiveness is hampered by drug resistance, but the mechanism is still unclear. We have found that SK-HEP-1 HCC cells transfected with a YB-X-1 overexpression plasmid subsequently developed into a stable YB-1 overexpression cell line (SK-HEP-1+YB-1) displayed increased invasion, migration, proliferation, and colony formation property as compared to the vector control (SKHEP1+Vec). The SK-HEP-1+YB-1 cell line also showed increased IC50 for sorafenib and elevated phosphorylation of Lyn (Y397) and further activated NF-kB (S165/S176) phosphorylation. This indicates YB-1 may cause increased Sorafenib resistance in HCC by activating tyrosine kinases (TK), such as lyn, and simultaneous activation of NF-kB. The combination of YB-1 inhibition and sorafenib might provide a novel therapeutic strategy and improve the survival of patients with advanced-stage HCC. Citation Format: Ana G. Ayala Pazzi, Omar Karkoutly, Kristopher Ezell, Samantha Lopez, Kyle D. Doxtater, Elias George, Vijian Dhevan, Manish K. Tripathi. Oncoprotein YB-1 modulation of Lyn-MAPK-NF-kB pathway, a potential therapeutic strategy combined with sorafenib for advanced stage HCC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1281.

YB-1 is a DNA- and RNA-binding protein that regulates expression of many important genes. Its deficiency or excess may pose threats, including malignant cellular transformation and metastasis, which explains the necessity of strict control over its amount at every level. As we showed previously, the 3' untranslated region (UTR) of YB-1 mRNA contains a regulatory element specifically binding to YB-1 and PABP (PABPC1). Also, we showed that YB-1 selectively inhibits YB-1 mRNA translation, while PABP stimulates it in a poly(A) tail-independent manner. It was suggested that regulation of YB-1 mRNA translation involves competition between PABP and YB-1 for binding to the regulatory element. Here we offer cogent evidence for this model and add novel details to the mechanism of regulation of YB-1 synthesis. In experiments on regulatory element deletion we showed that it is this element that is responsible for a specific effect of YB-1 and PABP on YB-1 mRNA translation. Mutations eliminating only specific YB-1 affinity for this element suppressed the inhibitory effect of YB-1 and concurrently dramatically decreased the PABP stimulating effect. Mutations reducing only specific PABP affinity for this element, as well as spatial separation of the YB-1- and PABP binding sites, did not affect the YB-1 inhibitory action but completely abolished the positive PABP effect. Together, these results unambiguously prove direct inhibitory action of YB-1 on its mRNA translation, while the positive effect of PABP is realized through displacing YB-1 from the regulatory element.

Targeting the Y-box Binding Protein-1 Axis to Overcome Radiochemotherapy Resistance in Solid Tumors

YBX1 at the crossroads of non-coding transcriptome, exosomal, and cytoplasmic granular signaling

Stress granules (SGs) are highly conserved cytoplasmic ribonucleoprotein complexes that modulate gene expression and cellular homeostasis under prototypical stress forms. SG formation protects cells under stress conditions by protecting untranslated mRNAs until stress relief, and cells that are incapable of forming SGs are more vulnerable to diverse stressors compared to cells that are proficient at SG formation. The transcription and translation regulation factor Y-box binding protein 1 (YB-1) is recruited to SG, but its exact contribution to formation of these structures is not clear. Using several stress inducing agents, arsenite, H2O2, piperlongumine, thapsigargin, heat shock, curcumin and hypoxia we demonstrate that YB-1 co-localizes to SG along with G3BP, TIA-1 and poly(A)+ mRNA in various human cancer cell lines. YB-1 inactivation by siRNA knockdown dramatically reduces the efficiency of SG assembly in two sarcoma cell lines, U2OS and Rh-30 and a prostate cancer cell line DU-145, with high YB-1 expression. We also found that si-YB-1 cells with an inefficient stress granule formation were more sensitive to stress induced by arsenite, H2O2, or piperlongumine compared to control cells. YB-1 influences SG assembly via two distinct mechanisms. First, it acts as a scaffold protein to recruit mRNA and SG associated RNA-binding proteins into SGs. Second, YB-1 regulates the mRNA translation of the essential nucleator SG proteins, G3BP and TIA-1, thus controlling their availability during SG assembly under oxidative stress. Finally, in vivo, downregulation of YB-1 significantly affected the formation of stress granules in primary tumors generated in mice. Taken together, YB-1 is critical in SG formation and cell survival. Citation Format: Syam Prakash Somasekharan, Gabriel Leprivier, Valentina Evdokimova, Amal EI-Naggar, Shamil Hajee, Martin Gleave, Poul HB Sorensen. YB-1 is critical for stress granule assembly and protects cells from oxidative stress. [abstract]. In: Proceedings of the AACR Special Conference on Pediatric Cancer at the Crossroads: Translating Discovery into Improved Outcomes; Nov 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;74(20 Suppl):Abstract nr A63.

Background: Hepatocellular carcinoma (HCC), the most prevalent form of liver cancer, is heavily influenced by socioeconomic and health disparities. In the Rio Grande Valley (RGV), risk factors such as Hepatitis B and C, diabetes, and non-alcoholic fatty liver disease (NAFLD) contribute significantly to HCC prevalence. McAllen, TX, ranks as the most obese city in the United States, compounding the HCC burden in this underserved area. Limited access to screening and early detection often results in late-stage diagnoses and poor outcomes. A deeper understanding of the molecular mechanisms driving HCC, particularly drug resistance, is crucial for improving early detection and treatment strategies. Our lab investigates the role of Y-Box Binding Protein 1 (YBX1) in HCC progression and resistance to sorafenib, the first-line tyrosine kinase inhibitor (TKI) for advanced HCC. YBX1, part of the Cold Shock Domain (CSD) protein superfamily, is a 324-amino acid protein involved in mRNA translation regulation via interactions with microRNAs and non-coding RNAs. While sorafenib shows initial efficacy, resistance frequently develops, and its mechanisms remain poorly understood. Methods: HCC cell lines were cultured following ATCC guidelines. Lentiviral overexpression plasmids for YBX1, incorporating GFP and a puromycin selection marker, were obtained from Abmgood. YBX1 expression was validated using Western blot and RT-PCR. Functional assays, including invasion, migration, proliferation, colony formation, and Xcelligence impedance analysis, were conducted to assess phenotypic changes. A phosphoproteome array identified kinase pathways influenced by YBX1, while specific kinase activators and inhibitors clarified YBX1-regulated signaling pathways linked to sorafenib resistance. Results: Analysis of The Cancer Genome Atlas (TCGA) confirmed that YBX1 expression is significantly elevated in HCC tumors compared to normal tissues and correlates with disease progression, metastasis, and poor survival. In vitro studies demonstrated that YBX1 overexpression (OE) enhanced invasion, migration, proliferation, and colony formation, while knockdown (KD) reduced these behaviors. Xcelligence assays further revealed accelerated proliferation in YBX1-OE cells and diminished growth in KD cells. Phosphoproteome analysis identified several kinases modulated by YBX1, and pathway analysis is ongoing to determine their roles in sorafenib resistance. Conclusion and Future Directions: We established GFP-expressing SK-Hep1 cell lines with stable YBX1 overexpression and knockdown, confirming YBX1’s role in driving oncogenic phenotypes in HCC. Ongoing proteomic studies aim to identify YBX1-associated proteins and pathways, with a focus on kinase modulation. These insights will enhance our understanding of sorafenib resistance mechanisms and inform the development of targeted therapies to overcome resistance in HCC. Citation Format: Yamile Abuchard Anaya, Ana Ayala Pazzi, Dennis Kwabiah, Veerababu Nagati, Ricardo Pequeno Bracho, Manish K. Tripathi. Potential pathways underlying sorafenib resistance in hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 5555.

The Y box-binding protein 1 (YB-1) is a DNA/RNA-binding protein that regulates mRNA transcription and translation. It is a major component of free messenger ribonucleoprotein particles and, at higher concentrations, blocks protein synthesis. In chicken embryo fibroblasts, overexpression of YB-1 confers a specific resistance to oncogenic cellular transformation by phosphoinositide 3-kinase (PI3K) or Akt/PKB. Recent studies have identified YB-1 as a direct substrate of Akt. The functional significance of Akt-mediated phosphorylation remains largely unknown. We generated YB-1 mutants in the Akt phosphorylation consensus sequence to explore the effect of phosphorylated YB-1 in PI3K-induced transformation. In contrast to wild-type YB-1, the phosphomimetic S99E mutant no longer interferes with cellular transformation. This mutant has reduced affinity for the cap of mRNAs and fails to inhibit cap-dependent translation. The data suggest that phosphorylation by Akt disables the inhibitory activity of YB-1 and thereby enhances the translation of transcripts that are necessary for oncogenesis. Overexpression of wild-type YB-1 overrides inactivation by Akt and maintains inhibition of protein synthesis and resistance to transformation.

The multifunctional protein Y-box binding protein 1 (YBX1), is a critical regulator of transcription and translation, and is widely recognized as an oncogenic driver in several solid tumors, including colorectal cancer (CRC). However, very little is known about the upstream or downstream factors that underlie YBX1′s regulation and involvement in CRC. Previously, we demonstrated that YBX1 overexpression correlated with potent activation of nuclear factor κB (NF-κB), a well-known transcription factor believed to be crucial in CRC progression. Here, we report a novel interaction between NF-κB, YBX1 and protein arginine methyltransferase 5 (PRMT5). Our findings reveal for the first time that PRMT5 catalyzes methylation of YBX1 at arginine 205 (YBX1-R205me2), an event that is critical for YBX1-mediated NF-κB activation and its downstream target gene expression. Importantly, when WT-YBX1 is overexpressed, this methylation exists under basal (unstimulated) conditions and is further augmented upon interleukin-1β (IL-1β) stimulation. Mechanistically, co-immunoprecipitation studies reveal that the R205 to alanine (A) mutant of YBX1 (YBX1-R205A) interacted less well with the p65 subunit of NF-κB and attenuated the DNA binding ability of p65. Importantly, overexpression of YBX1-R205A significantly reduced cell growth, migration and anchorage-independent growth of CRC cells. Collectively, our findings shed important light on the regulation of a novel PRMT5/YBX1/NF-κB axis through PRMT5-mediated YBX1-R205 methylation. Given the fact that PRMT5, YBX1 and NF-κB are all among top crucial factors in cancer progression, pharmacological disruption of this pivotal axis could serve as the basis for new therapeutics for CRC and other PRMT5/YBX1/NF-κB-associated cancers.

The multifunctional eukaryotic protein YB-1 (Y-box binding protein 1) plays a role in DNA reparation, transcription regulation, splicing, and mRNA translation, thereby participating in many crucial events in cells. Its effect is dependent mostly on its amount, and hence, on regulation of its synthesis. Published data on regulation of synthesis of YB-1 mediated by its mRNA 5′ UTR, and specifically on the 5′ UTR length and the presence of TOP-like motifs in this region, are contradictory. Here we report that 5′ UTRs of major forms of human, rabbit, and mouse YB-1 mRNAs are about 140 nucleotides long and contain no TOP-like motifs mentioned in the literature. Also, we have found that YB-1 specifically interacts with the 5′ UTR of its own mRNA within a region of about 100 nucleotides upstream from the start codon. Apart from YB-1, translation of YB-1 mRNA in a cell free system gives an additional product with an extended N-terminus and lower electrophoretic mobility. The start codon for synthesis of the additional product is AUC at position –(60–58) of the same open reading frame as that for the major product. Also, in the cell there is an alternative YB-1 mRNA with exon 1 replaced by a part of intron 1; YB-1 synthesized in vitro from this mRNA contains, instead of its N-terminal A/P domain, 10–11 amino acids encoded by intron 1.