Tcf-1 promotes genomic instability and T cell transformation in response to aberrant β-catenin activation

β-Catenin Regulates Glycolytic and Mitochondrial Function in T-Cell Acute Lymphoblastic Leukemia

Background: T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy characterized by a poor prognosis. β-catenin is implicated in the progression of T-ALL, yet the precise mechanisms of β-catenin involvement in the pathogenesis of T-ALL, particularly concerning metabolic processes, remain inadequately elucidated. Methods: A β-catenin knockout cell line was generated in the human leukemic cell line Jurkat using the CRISPR-Cas9 technique. Subsequently, assays were performed to evaluate cell proliferation, apoptosis, and metabolic activity. Comparative transcriptomic analysis was conducted between control cells and β-catenin knockout cells. Finally, a mouse xenograft model was employed to assess whether β-catenin knockout attenuates tumor growth and infiltration in vivo. Results: The deletion of β-catenin significantly inhibited proliferation and induced apoptosis. Additionally, the silencing of β-catenin led to the inhibition of glycolysis and a reduction in both mitochondrial mass and membrane potential. These results indicate that β-catenin may play a crucial role in regulating cell proliferation and apoptosis through the modulation of glycolytic activity and mitochondrial function in T-ALL. Conclusions: In summary, our findings uncover a novel mechanism by which β-catenin influences glycolysis and mitochondrial function in the progression of T-ALL, thereby identifying a potential therapeutic target for patients with relapsed T-ALL.

Elucidating the genotoxicity of Fusobacterium nucleatum-secreted mutagens in colorectal cancer carcinogenesis

BACKGROUND

Fusobacterium nucleatum (F. nucleatum) is one of the key tumorigenic bacteria in colorectal cancer (CRC), yet how F. nucleatum is involved in colorectal cancer carcinogenesis remains unknown.

RESULTS

In the present study, we carried out PathSeq analysis on RNA sequencing data from the 430 primary colon adenocarcinomas in TCGA database to assess the relationship between patients' survival and F. nucleatum abundance. Among patients with cecum and ascending colon tumors, we found that F. nucleatum transcriptome abundance is positively correlated with mutation load. We further demonstrated that patients with both high tumoral abundance of F. nucleatum and high mutation load exhibited poorer survival and DNA damage. We furthermore determined that F. nucleatum-conditioned medium (Fn. CM) induces DNA damage in both in vitro and in vivo studies. In addition, two F. nucleatum-secreted mutagens, namely DL-homocystine and allantoic acid, were identified to lead to DNA damage.

CONCLUSIONS

Our finding delineates the genotoxicity of F.nucleatum-secreted mutagens, which provides a basis for further work to investigate the role of F. nucleatum in the pathogenicity of CRC.

Stabilization of β-Catenin Directs HEB to Limit Thymic Selection

Activation of β-catenin in CD4+CD8+ double-positive (DP) thymocytes halts development before the thymic selection stage and predisposes to transformation. Leukemogenesis, but not the developmental block, depends on TCF-1, β-catenin's DNA-binding partner. In this study, we show that β-catenin activation directs the DNA-binding protein HEB to block DP thymocyte development. Conditional loss of HEB in DP thymocytes with stabilized β-catenin restores the frequencies of postselection TCRβhi/CCR7+ and TCRβhi/CD69+ DPs and their cell-cycle profile. This recovery is associated with significant reversal of β-catenin-induced expression changes, particularly those related to the CD69+ DP cell signature and to cell-cycle pathways. Stabilizing β-catenin in DP thymocytes directs HEB binding to ≈11,000 novel DNA sites throughout the genome. Novel HEB sites mark most CD69+ DP cell signature genes that change expression upon activation of β-catenin and then revert after loss of HEB. Moreover, many of the novel HEB sites occupy promoter regions of genes enriched in mitotic cell cycle pathways. HEB binding to those regions correlates with downregulation of the associated genes, and HEB inactivation restores expression to physiologic levels. These findings highlight a molecular interplay between HEB and β-catenin that can impair thymic development.

Comprehensive summary: the role of PBX1 in development and cancers

PBX1 is a transcription factor that can promote the occurrence of various tumors and play a reg-ulatory role in tumor growth, metastasis, invasion, and drug resistance. Furthermore, a variant generated by fusion of E2A and PBX1, E2A-PBX1, has been found in 25% of patients with childhood acute lymphoblastic leukemia. Thus, PBX1 is a potential therapeutic target for many cancers. Here, we describe the structure of PBX1 and E2A-PBX1 as well as the molecular mecha-nisms whereby these proteins promote tumorigenesis to provide future research directions for developing new treatments. We show that PBX1 and E2A-PBX1 induce the development of highly malignant and difficult-to-treat solid and blood tumors. The development of specific drugs against their targets may be a good therapeutic strategy for PBX1-related cancers. Furthermore, we strongly recommend E2A-PBX1 as one of the genes for prenatal screening to reduce the incidence of childhood hematological malignancies.

Clinicopathological implications of immunohistochemical expression of TBX21, CXCR3, GATA3, CCR4, and TCF1 in nodal follicular helper T-cell lymphoma and peripheral T-cell lymphoma, not otherwise specified

BACKGROUND

The classification of nodal peripheral T-cell lymphoma (PTCL) has evolved according to histology, cell-of-origin, and genetic alterations. However, the comprehensive expression pattern of follicular helper T-cell (Tfh) markers, T-cell factor-1 (TCF1), and Th1- and Th2-like molecules in nodal PTCL is unclear.

METHODS

Eighty-two cases of nodal PTCL were classified into 53 angioimmunoblastic T-cell lymphomas (AITLs)/nodal T-follicular helper cell lymphoma (nTFHL)-AI, 18 PTCLs-Tfh/nTFHL-not otherwise specified (NOS), and 11 PTCLs-NOS according to the revised 4th/5th World Health Organization classifications. Immunohistochemistry for TCF1, TBX21, CXCR3, GATA3, and CCR4 was performed.

RESULTS

TCF1 was highly expressed in up to 68% of patients with nTFHL but also in 44% of patients with PTCL-NOS (p > .05). CXCR3 expression was higher in AITLs than in non-AITLs (p = .035), whereas GATA3 expression was higher in non-AITL than in AITL (p = .007) and in PTCL-Tfh compared to AITL (p = .010). Of the cases, 70% of AITL, 44% of PTCLTfh/ nTFHL-NOS, and 36% of PTCL-NOS were subclassified as the TBX21 subtype; and 15% of AITL, 38% of PTCL-Tfh/nTFHL-NOS, and 36% of PTCL-NOS were subclassified as the GATA3 subtype. The others were an unclassified subtype. CCR4 expression was associated with poor progression-free survival (PFS) in patients with PTCL-Tfh (p < .001) and nTFHL (p = .023). The GATA3 subtype showed poor overall survival in PTCL-NOS compared to TBX21 (p = .046) and tended to be associated with poor PFS in patients with non-AITL (p = .054).

CONCLUSIONS

The TBX21 subtype was more prevalent than the GATA3 subtype in AITL. The GATA3 subtype was associated with poor prognosis in patients with non-AITL and PTCL-NOS.

Musashi-2 (MSI2) promotes neuroblastoma tumorigenesis through targeting MYC-mediated glucose-6-phosphate dehydrogenase (G6PD) transcriptional activation

Neuroblastoma (NB) is the deadliest pediatric solid tumor due to its rapid proliferation. Aberrant expression of MYCN is deemed as the most remarkable feature for the predictive hallmark of NB progression and recurrence. However, the phenomenon that only detection of MYCN in the nearly 20% of NB patients hints that there should be other vital oncogenes in the progression of NB. Here, we firstly show that MSI2 mRNA is augmented by analyzing public GEO datasets in the malignant stage according to International Neuroblastoma Staging System (INSS) stages. Although accumulating evidences uncover the emerging roles of MSI2 in several cancers, the regulatory functions and underlying mechanisms of MSI2 in NB remain under-investigated. Herein, we identified that high-expressed MSI2 and low-expressed n-Myc group account for 43.1% of total NB clinical samples (n = 65). Meanwhile, MSI2 expression is profoundly upregulated along with NB malignancy and negatively associated with the survival outcome of NB patients in the NB tissue microarray (NB: n = 65; Ganglioneuroblastoma: n = 31; Ganglioneuroma: n = 27). In vitro, our results revealed that MSI2 promoted migration, invasion, and proliferation of NB cells via enhancing pentose phosphate pathway. Mechanistically, MSI2 upregulated the key enzyme glucose-6-phosphate dehydrogenase (G6PD) via directly binding to 3'-untranslated regions of c-Myc mRNA to facilitate its stability, resulting in enhancing pentose phosphate pathway. Our findings reveal that MSI2 promotes pentose phosphate pathway via activating c-Myc-G6PD signaling, suggesting that MSI2 exhibits a novel and powerful target for the diagnosis and treatment of NB.

Modulating β-catenin/BCL9 interaction with cell-membrane-camouflaged carnosic acid to inhibit Wnt pathway and enhance tumor immune response

Introduction

Lung adenocarcinoma (LUAD) therapies are plagued by insufficient immune infiltration and suboptimal immune responses in patients, which are closely associated with the hyperactive Wnt/β-catenin pathway. Suppressing this signaling holds considerable promise as a potential tumor therapy for LUAD, but Wnt suppressor development is hindered by concerns regarding toxicity and adverse effects due to insufficient targeting of tumors.

Methods

We have synthesized a tumor-specific biomimetic Wnt pathway suppressor, namely CM-CA, by encapsulating carnosic acid within Lewis lung carcinoma (LLC) cell membranes. It possesses nano-size, allowing for a straightforward preparation process, and exhibits the ability to selectively target the Wnt/β-catenin pathway in lung adenocarcinoma cells. To evaluate its in vivo efficacy, we utilized the LLC Lewis homograft model, and further validated its mechanism of action through immunohistochemistry staining and transcriptome sequencing analyses.

Results

The findings from the animal experiments demonstrated that CM-CA effectively suppressed the Wnt/β-catenin signaling pathway and impeded cellular proliferation, leading to notable tumor growth inhibition in a biologically benign manner. Transcriptome sequencing analyses revealed that CM-CA promoted T cell infiltration and bolstered the immune response within tumor tissues.

Conclusion

The utilization of CM-CA presents a novel and auspicious approach to achieve tumor suppression and augment the therapeutic response rate in LUAD, while also offering a strategy for the development of Wnt/β-catenin inhibitors with biosafety profile.

Tp53 haploinsufficiency is involved in hotspot mutations and cytoskeletal remodeling in gefitinib-induced drug-resistant EGFRL858R-lung cancer mice

Tumor heterogeneity is the major factor for inducing drug resistance. p53 is the major defender to maintain genomic stability, which is a high proportion mutated in most of the cancer types. In this study, we established in vivo animal models of gefitinib-induced drug-resistant lung cancer containing EGFR^L858R and EGFR^L858R*Tp53^+/- mice to explore the molecular mechanisms of drug resistance by studying the genomic integrity and global gene expression. The cellular morphology of the lung tumors between gefitinib-induced drug-resistant mice and drug-sensitive mice were very different. In addition, in drug-resistant mice, the expression of many cytoskeleton-related genes were changed, accompanied by decreased amounts of actin filaments and increased amounts of microtubule, indicating that significant cytoskeletal remodeling is induced in gefitinib-induced drug-resistant EGFR^L858R and EGFR^L858R*Tp53^+/- lung cancer mice. The gene expression profiles and involved pathways were different in gefitinib-sensitive, gefitinib-resistant and Tp53^+/--mice. Increases in drug resistance and nuclear size (N/C ratio) were found in EGFR^L858R*Tp53^+/- drug-resistant mice. Mutational hotspot regions for drug resistance via Tp53^+/+- and Tp53^+/--mediated pathways are located on chromosome 1 and chromosome 11, respectively, and are related to prognosis of lung cancer cohorts. This study not only builds up a gefitinib-induced drug-resistant EGFR^L858R lung cancer animal model, but also provides a novel mutation profile in a Tp53^+/+- or Tp53^+/--mediated manner and induced cytoskeleton remodeling during drug resistance, which could contribute to the prevention of drug resistance during cancer therapy.