Low expression of Mda-7/IL-24 and high expression of C-myb in tumour tissues are predictors of poor prognosis for Burkitt lymphoma patients

iPSC-derived NK cells with site-specific integration of CAR19 and IL24 at the multi-copy rDNA locus enhanced antitumor activity and proliferation

The generation of chimeric antigen receptor-modified natural killer (CAR-NK) cells using induced pluripotent stem cells (iPSCs) has emerged as one of the paradigms for manufacturing off-the-shelf universal immunotherapy. However, there are still some challenges in enhancing the potency, safety, and multiple actions of CAR-NK cells. Here, iPSCs were site-specifically integrated at the ribosomal DNA (rDNA) locus with interleukin 24 (IL24) and CD19-specific chimeric antigen receptor (CAR19), and successfully differentiated into iPSC-derived NK (iNK) cells, followed by expansion using magnetic beads in vitro. Compared with the CAR19-iNK cells, IL24 armored CAR19-iNK (CAR19-IL24-iNK) cells showed higher cytotoxic capacity and amplification ability in vitro and inhibited tumor progression more effectively with better survival in a B-cell acute lymphoblastic leukaemia (B-ALL) (Nalm-6 (Luc1))-bearing mouse model. Interestingly, RNA-sequencing analysis showed that IL24 may enhance iNK cell function through nuclear factor kappa B (NFκB) pathway-related genes while exerting a direct effect on tumor cells. This study proved the feasibility and potential of combining IL24 with CAR-iNK cell therapy, suggesting a novel and promising off-the-shelf immunotherapy strategy.

The JAK2 inhibitor TG101209 exhibits anti-tumor and chemotherapeutic sensitizing effects on Burkitt lymphoma cells by inhibiting the JAK2/STAT3/c-MYB signaling axis

Constitutive activation of JAK2/STAT3 is a major oncogenic signaling event involved in the development of Burkitt lymphoma (BL). In the present study, we investigated the antilymphoma activity of TG101209, a specific JAK2 inhibitor, on EBV-positive and EBV-negative Burkitt lymphoma cell lines and primary BL cells. The results showed that TG101209 had a significant antilymphoma effect by inhibiting BL cell growth and inducing apoptosis along with cell differentiation toward mature B cells in vitro. We also found that TG101209 displayed significant synergistic action and a sensitizing effect on the anti-Burkitt lymphoma activity of doxorubicin. In vivo experiments indicated that TG101209 could suppress tumor growth and prolong the overall survival of BL cell-bearing mice. The mechanistic study indicated that TG101209, by suppressing the JAK2/STAT3/c-MYB signaling axis and crosstalk between the downstream signaling pathways, plays an antilymphoma role. These data suggested that TG101209 may be a promising agent or alternative choice for the treatment of BL.

DDX41 regulates the expression and alternative splicing of genes involved in tumorigenesis and immune response

DEAD‑box helicase 41 (DDX41) is an RNA helicase and accumulating evidence has suggested that DDX41 is involved in pre‑mRNA splicing during tumor development. However, the role of DDX41 in tumorigenesis remains unclear. In order to determine the function of DDX41, the human DDX41 gene was cloned and overexpressed in HeLa cells. The present study demonstrated that DDX41 overexpression inhibited proliferation and promoted apoptosis in HeLa cells. RNA‑sequencing analysis of the transcriptomes in overexpressed and normal control samples. DDX41 regulated 959 differentially expressed genes compared with control cells. Expression levels of certain oncogenes were also regulated by DDX41. DDX41 selectively regulated the alternative splicing of genes in cancer‑associated pathways including the EGFR and FGFR signaling pathways. DDX41 selectively upregulated the expression levels of five antigen processing and presentation genes (HSPA1A, HSPA1B, HSPA6, HLA‑DMB and HLA‑G) and downregulated other immune‑response genes in HeLa cells. Additionally, DDX41‑regulated oncogenes and antigen processing and presentation genes were associated with patient survival rates. Moreover, DDX41 expression was associated with immune infiltration in cervical and endocervical squamous cancer. The present findings showed that DDX41 regulated the cancer cell transcriptome at both the transcriptional and alternative splicing levels. The DDX41 regulatory network predicted the biological function of DDX41 in suppressing tumor cell growth and regulating cancer immunity, which may be important for developing anticancer therapeutics.

Regulation of MYB mediated cisplatin resistance of ovarian cancer cells involves miR-21-wnt signaling axis

c-MYB has been reported to be elevated in few cancers, including in ovarian cancer. It influences resistance to cisplatin but the details are not very well understood. The objective of this study was to further evaluate role of c-MYB in ovarian cancer’s cisplatin resistance. To elucidate the underlying mechanism of cisplatin resistance in ovarian cancer, we focused on the epigenetic regulation by miRNAs. Two cell lines, ES2 and OVCAR3, were used as the model systems. C-MYB expression was either up-regulated or silenced and the resulting effect on cisplatin resistance evaluated, along with the mechanistic role of miR-21, through transfections with pre/anti-miRNAs. An in vivo cisplatin resistance model was also employed to verify findings. High c-MYB correlated with increased miR-21. High c-MYB also resulted in induction of EMT and increased resistance against cisplatin which was attenuated by anti-miR-200s. c-MYB decreased β-catenin phosphorylation and thus activated wnt signaling. Silencing of c-MYB resulted in reduced miR-21 levels, reduced EMT, reduced cisplatin IC-50s and increased β-catenin phosphorylation. In an in vivo mice model of cisplatin resistance, c-MYB overexpressing ES2 xenografts were more aggressive than their control counterparts. These c-MYB overexpressing ES xenografts were significantly more resistant to cisplatin but could be sensitized to cisplatin by anti-miR-21. Our results provide a novel mechanism of cisplatin resistance by c-MYB which involves an essential role of miR-21.

Interleukin-24 Regulates T Cell Activity in Patients With Colorectal Adenocarcinoma

Interleukin (IL)-24 plays a potential anti-tumor activity in colorectal cancer in a dose-dependent manner. However, the immunoregulatory role of IL-24 to peripheral and tumor-infiltrating T cell function in colorectal cancer was not fully elucidated. In this study, twenty-nine colorectal adenocarcinoma patients and fifteen healthy individuals were enrolled. IL-24 expression and IL-24 receptor (IL-20R1, IL-20R2, and IL-22R1) mRNA relative level was measured by ELISA and real-time PCR, respectively. CD4⁺ and CD8⁺ T cells were purified from peripheral bloods and cancer specimens, and were stimulated with low (10 ng/ml) and high (100 ng/ml) concentration of recombinant IL-24. CD4⁺ T cells activity was assessed by measurement of Th cell percentage, transcriptional factors, and cytokine production. CD8⁺ T cells activity was evaluated by investigation of cytotoxic molecules, target cell death, and interferon-γ (IFN-γ) secretion. IL-24 was decreasingly expressed in both peripheral bloods and cancer tissues in colorectal adenocarcinoma patients. However, IL-20R1 and IL-20R2 was comparable between healthy controls and colorectal adenocarcinoma patients. Low concentration of IL-24 suppressed CD4⁺ T cell proliferation. In contrast, high concentration of IL-24 not only promoted CD4⁺ T cell proliferation, but also enhanced CD4⁺ T cell activity, which mainly presented as up-regulation of Th1/Th17 frequency, T-bet/RORγt mRNA, and IFN-γ/IL-17 production but down-regulation of Treg percentage, FoxP3 mRNA, and IL-10/IL-35 secretion. Moreover, high concentration of IL-24 also increased perforin and granzyme B expression in CD8⁺ T cells, and elevated cytolytic and non-cytolytic activity of CD8⁺ T cells, which presented as induction of target cell death and elevation of IFN-γ expression. However, low concentration of IL-24 did not affect bioactivity of CD8⁺ T cells. The current data indicated that IL-24 might regulate T cell function in a dose-dependent manner. High-concentration of IL-24 might promote anti-tumor immune responses in development novel therapeutic approaches to colorectal adenocarcinoma.

c-Myb promotes growth and metastasis of colorectal cancer through c-fos-induced epithelial-mesenchymal transition

c-Myb is a crucial transcription factor that participates in various biological functions; however, its role in colorectal cancer (CRC) remains poorly investigated. We first analyzed the expression and clinical significance of c-Myb in a retrospective cohort enrolling 132 CRC patients. Then, the CRISPR/Cas9 technique was used to establish c-Myb gene KO CRC cell lines. Cellular functional assays in vitro and in vivo were used to evaluate the impact of c-Myb KO in CRC cells. Finally, RNA sequencing was used to investigate the potential oncogenic mechanisms regulated by c-Myb in CRC progression and related cellular validations were accordingly carried out. As a result, c-Myb is significantly overexpressed in CRC tissues as compared with adjacent normal tissues. High expression of c-Myb is positively correlated with lymph node metastasis and poor prognosis. Univariate analysis and multivariate analysis further identify c-Myb as an independent unfavorable prognostic factor for CRC patients. c-Myb KO inhibits the proliferation, apoptosis resistance, invasion, metastasis, colony formation and in vivo tumorigenesis of CRC cells. Also, the mechanism investigation indicates that c-Myb may promote CRC progression by regulating c-fos. c-fos overexpression can rescue the inhibitory effect of c-Myb KO on the malignant characteristics of CRC cells. Finally, we find that c-Myb KO inhibits the epithelial-mesenchymal transition (EMT) molecular phenotype in CRC cells, whereas c-fos overexpression can rescue this inhibitory effect. This study suggests that c-Myb promotes the malignant progression of CRC through c-fos-induced EMT and has the potential to be a promising prognostic biomarker and therapeutic target.

Recent insights into apoptosis and toxic autophagy: The roles of MDA-7/IL-24, a multidimensional anti-cancer therapeutic

Apoptosis and autophagy play seminal roles in maintaining organ homeostasis. Apoptosis represents canonical type I programmed cell death. Autophagy is viewed as pro-survival, however, excessive autophagy can promote type II cell death. Defective regulation of these two obligatory cellular pathways is linked to various diseases, including cancer. Biologic or chemotherapeutic agents, which can reprogram cancer cells to undergo apoptosis- or toxic autophagy-mediated cell death, are considered effective tools for treating cancer. Melanoma differentiation associated gene-7 (mda-7) selectively promotes these effects in cancer cells. mda-7 was identified more than two decades ago by subtraction hybridization showing elevated expression during induction of terminal differentiation of metastatic melanoma cells following treatment with recombinant fibroblast interferon and mezerein (a PKC activating agent). MDA-7 was classified as a member of the IL-10 gene family based on its chromosomal location, and the presence of an IL-10 signature motif and a secretory sequence, and re-named interleukin-24 (MDA-7/IL-24). Multiple studies have established MDA-7/IL-24 as a potent anti-cancer agent, which when administered at supra-physiological levels induces growth arrest and cell death through apoptosis and toxic autophagy in a wide variety of tumor cell types, but not in corresponding normal/non-transformed cells. Furthermore, in a phase I/II clinical trial, MDA-7/IL-24 administered by means of a non-replicating adenovirus was well tolerated and displayed significant clinical activity in patients with multiple advanced cancers. This review examines our current comprehension of the role of MDA-7/IL-24 in mediating cancer-specific cell death via apoptosis and toxic autophagy.