[Research Progress of Regulatory T Cells in the Pathogenesis of Multiple Myeloma --Review].

The multiple myeloma (MM), the second most common hematologic malignancy, is malignant proliferative disease of plasma cells. Although the application of many targeted drugs has significantly prolonged the survival time of MM patients, it is still an incurable disease. In recent years, the immunosuppression caused by interaction between tumor microenvironment(TME) and tumor cells has attracted people's attention gradually. As a kind of immunosuppressive cells in TME, regulatory T cells (Treg) play an important role in the progress of MM. Treg is related to the proliferation and metastasis of tumors, and can lead to the progress of MM by promoting the angiogenesis and generating immunosuppressive TME. In this review, we briefly summarized the latest research progress on the impact of Treg on the pathogenesis of MM.

Clinicopathological and Gene Mutation Analysis of 27 Cases with Extranodal Rosai-Dorfman Disease.

Objective: To investigate the clinicopathological features, and mutations of NRAS, KRAS, BRAF and MAP2K1 genes in extranodal Rosai-Dorfman disease (RDD). Methods: The clinic opathological features of 27 patients with extranodal RDD were retrospectively analyzed, and the NRAS, KRAS, BRAF and MAP2K1 genes mutation were detected by Sanger sequencing. Results: The male to female ratio was 1.7:1. The average age was 46.9 years. There were skin lesions in 12 cases (44.4%) and head and neck lesions in 8 cases (29.6%). Microscopically, those patients with skin RDD had lesions characterized by clear and dark intervals and obvious emperipolesis, while in other parts, the background was more complex. About 21.1% (4/19) had mutations, including 3 mutations in NRAS 2 exon and 1 mutation in KRAS 2 exon. Two of the three NRAS mutations were located in the skin, accounting for 20% (2/10) of skin RDD. Conclusion: Extranodal RDD was more common in males than in females, and might occur in all ages, with a greater incidence in skin, head, and neck. Besides the obvious microscopic characteristics in those with skin RDD, the background of other parts was complex and easily missed or misdiagnosed. Some RDD with gene mutations, mainly in NRAS 2 exon, especially in skin RDD, support partial RDD is a clonal disease.

Dysregulation of LINC00470 and METTL3 promotes chemoresistance and suppresses autophagy of chronic myelocytic leukaemia cells.

Cytoplasmic lncRNAs have been found to directly interact with target mRNAs and regulate their stability. In this study, we aimed to study the molecular mechanism underlying the function of m6 A as a central regulator in chemoresistance and CML proliferation. In this study, we established three mice groups (control group, ADR-R group and ADR-R + shLINC00470 group). We detected PTEN mRNA expression in the presence of LINC00470 in the mice models, as well as in the KCL22 and K562 cells. LINC00470 was significantly enriched for PTEN mRNA to exhibit a negative regulatory relationship between LINC00470 and PTEN mRNA. However, the alteration of LINC00470 had no effect on the luciferase activity of PTEN promoter, while the half-life of PTEN mRNA was affected. It was further validated that LINC00470 down-regulated PTEN expression by positively regulating the m6A modification of PTEN mRNA via RNA methyltransferase METTL3. Moreover, the relative expression of LC3II, Beclin-1, ATG7 and ATG5 was all decreased in cells treated with LINC00470, and down-regulated PTEN expression was observed in chemo-resistant cells, while the expression of PTEN was rescued by the transfection of shMETTL3 into chemo-resistant cells. Moreover, the knockdown of METTL3 also restored the normal level of PTEN m6 A modification and LINC00470 expression in chemo-resistant cells. In conclusion, our results demonstrated the molecular mechanism underlying the effect of LINC00470 on CML by reducing the PTEN stability via RNA methyltransferase METTL3, thus leading to the inhibition of cell autophagy while promoting chemoresistance in CML.

[Inhibitory Effect of PKC412 Against Human Acute Leukemia Cell Line HL-60 Cells].

OBJECTIVE: To explore the effects and mechanisms of PKC412 inhibitor on proliferation and apoptosis of HL-60 cell line. METHODS: CCK-8 assay was used to detect the effect of PKC412 on the proliferation of HL-60 cells at different concentrations; Wright-Giemsa staining was used to estimated the effect of PKC412 on the apoptosis of HL-60 cells; the mRNA expression of BCL-2 and P53 genes was detected by qRT-PCR, the expression of BCL-2 and P53 proteins was detected by Western blot. HL-60 cells were injected into mouse caudal vein to construct acute myeloid leukemia model, PKC412 was administered to tail vein for 31.25 nmol/kg, normal saline was injected into the same site of the mice as control group, and the inhibitory effect of PKC412 on HL-60 cells in mice was observed. ELISA assay was used to detect the effect of PKC412 on the inflammatory factors of TNF-α and TGF-ß in tumor mice. RESULTS: PKC412 could inhibit the proliferation of HL-60 cell, which was in a dose dependent manner(r=0.9973) (IC50 was 0.31 µmol/L), and induce apoptosis of HL-60 cells. After HL-60 cell was treated by PKC412 for 48 h the expression of BCL-2 gene was down regulated(0.417±0.044 vs 0.933±0.033, t=9.347, P<0.001), the expression of P53 gene was up regulated(1.533±0.145 vs 1.050±0.161, t=2.231, P>0.05) as compared with control group. And the expression of BCL-2 protein was decreased, while the expression of P53 protein was increased. PKC412 could inhibited the growth of HL-60 tumor cells in vivo, the survival rate of mice after administration was 50% and the weight was increased as compared with that in control group(18.02±0.403 g vs 16.44±0.562 g, t=2.272, P=0.0356). The secretion of TNF-α and TGF-ß cytokine in serum and spleen cells in PKC412 group was significantly lower than that in control group (P<0.05). CONCLUSION: PKC412 can induce apoptosis of HL-60 cells by inhibiting the expression level of BCL-2 gene, PKC412 administration in vivo can inhibit the growth of the tumors.

Could cytokine release syndrome induce acute myelofibrosis in CD19 chimeric antigen receptor T cells therapy?

CAR-T cells therapy can give rise to most common and concerning two side effects - cytokine release syndrome (CRS) and neurotoxicity. But in our CD19 CAR-T cells therapy clinical trial, we observed 1 out of 17 patients with B-cell acute lymphoblastic leukemia (B-ALL) developed acute myelofibrosis(AMF) after grade IV CRS post to the CD19 CAR-T cells therapy. This finding suggests that the CAR-T cells therapy may have rare and serious AMF, which we should pay important attention to. Trial registration:NCT02968472. Registered 18 November 2016 - Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT02968472.