FAT1 inhibits the proliferation of DLBCL cells via increasing the m6A modification of YAP1 mRNA

Emerging evidence shows that FAT atypical cadherin 1 (FAT1) mutations occur in lymphoma and are associated with poorer overall survival. Considering that diffuse large B cell lymphoma (DLBCL) is the category of lymphoma with the highest incidence rate, this study aims to explore the role of FAT1 in DLBCL. The findings demonstrate that FAT1 inhibits the proliferation of DLBCL cell lines by downregulating the expression of YAP1 rather than by altering its cellular localization. Mechanistic analysis via meRIP-qPCR/luciferase reporter assays showed that FAT1 increases the m6A modification of YAP1 mRNA 3'UTR and the subsequent binding of heterogeneous nuclear ribonucleoprotein D (HNRNPD) to the m6A modified YAP1 mRNA, thus decreasing the stability of YAP1 mRNA. Furthermore, FAT1 increases YAP1 mRNA 3'UTR m6A modification by decreasing the activity of the TGFβ-Smad2/3 pathway and the subsequent expression of ALKBH5, which is regulated at the transcriptional level by Smad2/3. Collectively, these results reveal that FAT1 inhibits the proliferation of DLBCL cells by increasing the m6A modification of the YAP1 mRNA 3'UTR via the TGFβ-Smad2/3-ALKBH5 pathway. The findings of this study therefore indicate that FAT1 exerts anti-tumor effects in DLBCL and may represent a novel target in the treatment of this form of lymphoma.

[Effect of adenovirus-mediated shRNA down-regulates SHP2 expression on the apoptosis of human hepatic stellate cells LX-2]

Objective: To investigate the effect of adenovirus-mediated short hairpin RNA (shRNA) downregulating SH2 domain-containing protein tyrosine phosphatase 2 (SHP2) on the apoptosis of human hepatic stellate cells LX-2 cultured in vitro. Methods: The recombinant adenovirus Ad-shRNA/SHP2 carrying shRNA targeted SHP2 and expressing green fluorescent protein (GFP), and the empty control virus Ad-GFP expressing GFP were transfected into LX-2 cells cultured in vitro. Real-time fluorescence quantitative PCR was used to detect SHP2 mRNA expression in LX-2 cells. Western blot was used to detect the protein expressions of SHP2, Bax, and Bcl-2 in LX-2 cells. TUNEL and annexin-V/propidium iodide dual-labeled flow cytometry were used to detect apoptosis in LX-2 cells. Experimental group: (1) Control group: LX-2 cells were transfected with DMEM instead of adenovirus; (2) Ad-GFP group: transfected with empty virus Ad-GFP; (3) Ad-shRNA/SHP2 group: transfected with recombinant adenovirus Ad-shRNA/SHP2. The means between multiple groups were compared using a one-way ANOVA and the LSD test was used for inter group comparisons. Results: shRNA-targeted SHP2 significantly down-regulated the expression of SHP2 protein and mRNA in LX-2 cells (P < 0.05). The TUNEL and annexin-V/propidium iodide dual-labeled flow cytometry results showed that the apoptosis rate of LX-2 cells in the Ad-shRNA/SHP2 group (12.755%±1.606%, 19.340%±2.505%) (P < 0.05) was significantly higher compared to the control group (3.077%±0.731%, 9.438%±0.804%) and the Ad-GFP group (3.250%±0.851%, 8.893%±1.982%), with no statistically significant difference between the control group and the Ad-GFP group (P > 0.05). Western blot analysis of Bax and Bcl-2 protein expression in LX-2 cells of each group revealed that the Bax protein expression was significantly higher in the Ad shRNA/SHP2 group (2.493 ± 0.203) (P < 0.05) compared to the control group and Ad-GFP group (1.989 ± 0.147, 1.999 ± 0.162), with no statistically significant difference between the control group and the Ad-GFP group (P > 0.05), while the Bcl-2 protein was significantly decreased in the Ad-shRNA/SHP2 group (1.042±0.148) compared with the control group and the Ad-GFP group (1.707±0.146, 1.521±0.142), with no statistically significant difference between the control group and the Ad-GFP group (P > 0.05). Conclusions: SHP2 expression down-regulation induces apoptosis of human hepatic stellate cells LX-2 in vitro by reducing Bcl-2/Bax.

An acquired BMF with FANCL gene heterozygous mutation: Case report

RATIONALE

Bone marrow failure (BMF) includes inherited and acquired BMFs. Acquired BMF can be secondary to various factors, such as autoimmune dysfunction, benzene, drugs, radiation, viral infection and so on. Fanconi anemia (FA) complementation group L (FANCL) is an E3 ubiquitin ligase that participates in the repair of DNA damage. Homozygous or compound heterozygous mutations of FANCL can lead to the onset of FA, which is one of the most common inherited BMFs.

PATIENT CONCERNS AND DIAGNOSES

Here, we report a case of acquired BMF. This patient had a history of benzene exposure for half a year before the onset of the disease, and presented with progressive pancytopenia, especially the reduction of erythrocytes and megakaryocyte, without malformation. Interestingly, this patient and his brother/father had a heterozygous (non-homozygous/compound heterozygous) mutation (Exon9, c.745C > T, p.H249Y) in the FANCL gene.

INTERVENTIONS AND OUTCOMES

The patient successfully underwent unrelated and fully compatible umbilical cord blood hematopoietic stem cell transplantation.

LESSONS SUBSECTIONS

We report for the first time an acquired BMF case with FANCL gene heterozygous mutation, and the mutation site (Exon9, c.745C > T, p.H249Y) has never been reported. This case suggests that heterozygous mutations in FANCL gene may be associated with increased susceptibility to acquired BMF. Based on current reports and this case, we speculate that heterozygous mutations in the FA complementation gene may exist in a certain proportion of tumor and acquired BMF patients, but have not been detected. We recommend routine screening for FA complementation gene mutations in tumor and acquired BMF patients in clinical practice. If positive results are found, further screening can be conducted on their families.

Family Aggregation of Hematological Malignancies Discovered from an Acute Myeloid Leukemia Patient with STK11 and THBD Gene Mutation

Acute myeloid leukemia (AML) is a large class of heterogeneous hematological malignancies with the highest incidence rate in acute leukemia. Its pathogenesis is still unclear, which may be related to genetics. According to the latest AML NCCN guidelines, genes involved in AML family genetic changes include RUNX1, ANKRD26, CEBPA. Finding new genes related to AML genetics is of great significance for predicting the prognosis of patients, developing targeted drugs, and selecting transplant donors. Here, we report a case of adult female AML patient whose three relatives suffered from hematological malignancies, including Waldenstrom macroglobulinemia, NK/T-cell lymphoma, and angioimmunoblastic T-cell lymphoma. The screen for genetic susceptibility genes related to blood and immune system diseases was carried out, and the result showed that the patient herself, her son, her daughter, and her two cousins all had STK11 p.F354L and/or THBD p.D486Y mutations. At present, there is no research or case report on the relationship between STK11/THBD and family aggregation of hematological malignancies. We report for the first time that an AML patient with STK11 and THBD mutations has a family aggregation of hematological malignancies, and consider that STK11 and THBD may be related to family genetic changes which ultimately cause the family aggregation of hematological malignancies.

Enhanced antitumor effect of combining chemotherapy with Epstein-Barr virus (EBV)-specific cytotoxic T lymphocytes in mice with EBV-related non-Hodgkin's lymphoma

Epstein-Barr virus (EBV)-related non-Hodgkin's lymphoma (NHL) represents a major problem in hematological clinical studies due to its drug tolerance and refractoriness. EBV infection is a key factor driving the process of tumor growth. Immune therapy is an important biotherapeutic method of treating cancer, which is attracting increasing attention. We hypothesized that combining conventional chemotherapy with immune therapy in the treatment of EBV-related NHL may achieve better outcomes. First, we successfully cloned large numbers of EBV-specific T cells by immune stimulation ex vivo. Subsequently, the combined therapy was applied in a murine model of human EBV-related NHL. As expected, combined therapy inhibited tumor growth more effectively compared with monotherapy. In addition, we continuously tested the tumor-associated immune microenvironment and observed that the numbers of tumor-infiltrating cytotoxic T lymphocytes (CTLs) and macrophages were elevated following combined therapy. These effects suggest that EBV-specific CTLs may indirectly promote an innate immune reaction in lymphoma by activating tumor-infiltrating macrophage proliferation. Our findings may provide a guide for the prospective treatment of EBV-related NHL.