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Background/aim Colorectal cancer (CRC) is one of the most common malignant tumors in the world. This study aimed to investigate the anticancer effect of the combination treatment of Ribociclib (LEE011) and 5-Fluorouracil (5-FU) on CRC cells. Materials and methods HT-29 and SW480 cells were treated with LEE011, 5-FU, or the combination of LEE011 and 5-FU. Cell viability and cycle were investigated through 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay and flow cytometry. The expression of cell cycle-related proteins was determined through western blot. Results The combined treatment of LEE011 with 5-FU synergistically reduced cell viability in HT-29 and SW480 cells. Specifically, it induced cell cycle arrest at the G1 phase, down-regulated the phosphorylation of retinoblastoma protein and the expression of p53. Conclusion LEE011 exhibited potential as an effective therapeutic inhibitor for the combination treatment of CRC patients.

BACKGROUND: This study investigated whether xenotransplantation of human Wharton’s jelly-derived mesenchymal stem cells (WJ-MSCs) reduces thioacetamide (TAA)-induced mouse liver fibrosis and the underlying molecular mechanism. METHODS: Recipient NOD/SCID mice were injected intraperitoneally with TAA twice weekly for 6 weeks before initial administration of WJ-MSCs. Expression of regenerative and pro-fibrogenic markers in mouse fibrotic livers were monitored post cytotherapy. A hepatic stallate cell line HSC-T6 and isolated WJ-MSCs were used for in vitro adhesion, migration and mechanistic studies. RESULTS: WJ-MSCs were isolated from human umbilical cords by an explant method and characterized by flow cytometry. A single infusion of WJ-MSCs to TAA-treated mice significantly reduced collagen deposition and ameliorated liver fibrosis after 2-week therapy. In addition to enhanced expression of hepatic regenerative factor, hepatocyte growth factor, and PCNA proliferative marker, WJ-MSC therapy significantly blunted pro-fibrogenic signals, including Smad2, RhoA, ERK. Intriguingly, reduction of plasma fibronectin (pFN) in fibrotic livers was noted in MSC-treated mice. In vitro studies further demonstrated that suspending MSCs triggered pFN degradation, soluble pFN conversely retarded adhesion of suspending MSCs onto type I collagen-coated surface, whereas pFN coating enhanced WJ-MSC migration across mimicked wound bed. Moreover, pretreatment with soluble pFN and conditioned medium from MSCs with pFN strikingly attenuated the response of HSC-T6 cells to TGF-β1-stimulation in Smad2 phosphorylation and RhoA upregulation. CONCLUSION: These findings suggest that cytotherapy using WJ-MSCs may modulate hepatic pFN deposition for a better regenerative niche in the fibrotic livers and may constitute a useful anti-fibrogenic intervention in chronic liver diseases. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s13770-020-00274-4) contains supplementary material, which is available to authorized users.

There is high risk of metastasis and recurrence in head and neck squamous cell carcinoma (HNSCC) patients, especially for patient who received definitive surgery and adjuvant radiotherapy. Aberrant activation of PI3K/AKT/mTOR signaling occurs in approximately 80% of HNSCC, which has been indicated to serve as prognostic biomarkers for patients suffer from recurrence or metastasis. Therefore, in this study, we focus on the relationship between the expression level of signaling factors in PI3K/AKT/mTOR pathway and recurrence tumor from HNSCC patients. A tissue microarray (TMA) was constructed from 54 cases of HNSCC patients who received definitive surgery and adjuvant radiotherapy, are followed more than 5 years, and with no previous malignancy and synchronous tumor. Slides were scored and dichotomized by two pathologists and scores. Based on the TMA block with IHC staining, the results showed that PI3K/AKT/mTOR signaling was highly activated both in recurrence and non-recurrence patients. Particularly, in the recurrence population, the results showed the low expression phospho-eukaryotic initiation factor 4E (p-eIF4E) or high expression eIF4E, phospho-eIF4E binding protein 1 (p-4EBP1), phospho-ribosomal protein S6 kinase beta-1 (p-S6K1) and phospho-40S ribosomal protein S6 (p-S6R) exhibited worse overall survival. The expression level of eIF4E and p-4EBP1 were significantly associated with tumor recurrence and recurrence-free survival. Furthermore, high expression level of eIF4E and p-4EBP1 had worse recurrence-free survival. In conclusion, the expression of eIF4E and p-4EBP1 should be considered as predictive biomarkers for the HNSCC patients. This may contribute to potential predictive biomarkers for HNSCC patient who receive adjuvant radiotherapy.

Chronic lymphocytic leukemia (CLL) still remains an incurable disease as the cells evade apoptosis, which is an obstacle for current therapeutic approaches. Therefore, our aim was to identify an ideal target of leukemic cell growth for developing inhibitors.Mouse lymphocytic leukemia cell line L1210, human Toledo cells and a DBA/2 mouse graft model were used to analyze the activity of dual mTORC1/2 inhibitor AZD2014s. Western blotting and flow cytometry were performed to determine the mechanism.AZD2014 inhibited L1210 and human Toledo cell proliferation. Treatment with AZD2014 reduced the phosphorylation levels of S6K1 and 4EBP1 and the protein levels of Rictor, a component of the mTORC2 pathway. AZD2014 induced cell cycle arrest at the GThe mTORC1/2 inhibitor may be a better therapeutic agent compared to PI3K/mTORC1 inhibitors for treating patients with CLL.

Radiotherapy (RT) combined with a radiosensitizer represents an important treatment for head and neck squamous cell carcinoma (HNSCC). Only few chemotherapy agents are currently approved as radiosensitizers for targeted therapy. In this study, the potent cyclin-dependent kinase 4/6 (CDK4/6) inhibitor LEE011 was tested for potential to act as a radiosensitizer during RT.RT enhancement by LEE011 was assessed by in vitro clonogenic assay, flow cytometry, and western blot in a variety of HNSCC cell lines. The HNSCC cell line OML1 and its radiation-resistant clone OML1-R were used.LEE011 induced cell-cycle arrest in SCC4/SCC25 cells during the GLEE011 is a potential radiosensitizer that can enhance the cytotoxic effects of RT. Clinical trials including LEE011 during RT for HNSCC should be considered.

The expression of CD127, the IL-7–binding subunit of the IL-7 R, is tightly regulated during the development and activation of T cells and is reduced during chronic viral infection. However, the molecular mechanism regulating the dynamic expression of CD127 is still poorly understood. In this study, we report that the transcription factor Ets-1 is required for maintaining the expression of CD127 in murine peripheral T cells. Ets-1 binds to and activates the CD127 promoter, and its absence leads to reduced CD127 expression, attenuated IL-7 signaling, and impaired IL-7–dependent homeostatic proliferation of T cells. The expression of CD127 and Ets-1 is strongly correlated in human T cells. Both CD127 and Ets-1 expression are decreased in CD8+ T cells during HIV infection. In addition, HIV-associated loss of CD127 is only observed in Ets-1low effector memory and central memory but not in Ets-1high naive CD8+ T cells. Taken together, our data identify Ets-1 as a critical regulator of CD127 expression in T cells.

E26 transformation-specific sequence 1 (Ets-1), the prototype of the ETS family of transcription factors, is critical for the expression of IL-2 by murine Th cells; however, its mechanism of action is still unclear. Here we show that Ets-1 is also essential for optimal production of IL-2 by primary human Th cells. Although Ets-1 negatively regulates the expression of Blimp1, a known suppressor of IL-2 expression, ablation of B lymphocyte-induced maturation protein 1 (Blimp1) does not rescue the expression of IL-2 by Ets-1-deficient Th cells. Instead, Ets-1 physically and functionally interacts with the nuclear factor of activated T-cells (NFAT) and is required for the recruitment of NFAT to the IL-2 promoter. In addition, Ets-1 is located in both the nucleus and cytoplasm of resting Th cells. Nuclear Ets-1 quickly exits the nucleus in response to calcium-dependent signals and competes with NFAT proteins for binding to protein components of noncoding RNA repressor of NFAT complex (NRON), which serves as a cytoplasmic trap for phosphorylated NFAT proteins. This nuclear exit of Ets-1 precedes rapid nuclear entry of NFAT and Ets-1 deficiency results in impaired nuclear entry, but not dephosphorylation, of NFAT proteins. Thus, Ets-1 promotes the expression of IL-2 by modulating the activity of NFAT.

PTPN22 is a tyrosine phosphatase and functions as a damper of TCR signals. A C-to-T single nucleotide polymorphism (SNP) located at position 1858 of human PTPN22 cDNA and converting an arginine (R620) to tryptophan (W620) confers the highest risk of rheumatoid arthritis among non-HLA genetic variations that are known to be associated with this disease. The effect of the R-to-W conversion on the phosphatase activity of PTPN22 protein and the impact of the minor T allele of the C1858T SNP on the activation of T cells has remained controversial. In addition, how the overall activity of PTPN22 is regulated and how the R-to-W conversion contributes to rheumatoid arthritis is still poorly understood. Here we report the identification of an alternative splice form of human PTPN22, namely PTPN22.6. It lacks the nearly entire phosphatase domain and can function as a dominant negative isoform of the full length PTPN22. Although conversion of R620 to W620 in the context of PTPN22.1 attenuated T cell activation, expression of the tryptophan variant of PTPN22.6 reciprocally led to hyperactivation of human T cells. More importantly, the level of PTPN22.6 in peripheral blood correlates with disease activity of rheumatoid arthritis. Our data depict a model that can reconcile the conflicting observations on the functional impact of the C1858T SNP and also suggest that PTPN22.6 is a novel biomarker of rheumatoid arthritis.

Many advances in our understanding of the molecules that regulate the development, differentiation and function of T cells have been made over the past few years. One important regulator of T-cell differentiation is the transcription factor GATA-binding protein 3 (GATA3). Although the main function of GATA3 is to act as a master transcription factor for the differentiation of T helper 2 (T(H)2) cells, new research has helped to uncover crucial functions of GATA3 in T cells that go beyond T(H)2-cell differentiation and that are important at earlier stages of haematopoietic and lymphoid-cell development. This Review focuses on the functions of GATA3 from early thymocyte development to effector T-cell differentiation. In addition, we discuss the interactions between GATA3 and other transcription factors and signalling pathways, and highlight the functional significance of the GATA3 protein structure.

C-Maf plays an important role in regulating cytokine production in TH cells. Its transactivation of IL-4 is optimized by phosphorylation at Tyr21, Tyr92, and Tyr131. However, the molecular mechanism regulating its tyrosine phosphorylation remains unknown. In this study, we demonstrate that Tec kinase family member Tec, but not Rlk or Itk, is a tyrosine kinase of c-Maf and that Tec enhances c-Maf-dependent IL-4 promoter activity. This effect of Tec is counteracted by Ptpn22, which physically interacts with and facilitates tyrosine dephosphorylation of c-Maf thereby attenuating its transcriptional activity. We further show that phosphorylation of Tyr21/92/131 of c-Maf is also critical for its recruitment to the IL-21 promoter and optimal production of this cytokine by TH17 cells. Thus, manipulating tyrosine phosphorylation of c-Maf through its kinases and phosphatases can have significant impact on TH cell-mediated immune responses.