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.

[Efficacy and Safety of Ixazomib Combined with Thalidomide and Dexamethasone in Treatment of Multiple Myeloma].

OBJECTIVE: To investigate the efficacy and safety of ixazomib combined with thalidomide and dexamethasone in the treatment of multiple myeloma (MM). METHODS: The clinical data of 60 MM patients admitted to our center from January 2019 to June 2022 were analyzed retrospectively, including 43 newly diagnosed patients and 17 patients with recurrence and progression. All patients were treated with ixazomib combined with thalidomide and dexamethasone, and completed 2 to 7 treatment cycles. RESULTS: The overall response rate (ORR) of all patients was 98.3%. Among them, 53 patients completed 4 treatment cycles, and the ORR was 86.8%. Seventeen patients completed the whole treatment cycle, with curative effect reaching 88.2% achieving very good partial response and above, and 52.9% achieving complete response and above. Albumin and ß2-microglobulin of all patients had been improved rapidly after treatment. The deadline was August 31, 2022. The median follow-up time was 14(3-24) months, and overall survival (OS) rate was 86.67%. The OS rate of patients with recurrence and progression was significantly lower than that of newly diagnosed patients (P < 0.05). The most common adverse reaction of hematology was lymphopenia (53.3%), followed by anemia (33.3%). The most common non-hematological adverse reaction was fatigue (68.33%), followed by peripheral neuropathy (31.67%). CONCLUSION: Ixazomib combined with thalidomide and dexamethasone is effective in the treatment of MM, with good short-term efficacy, survival and safety. However, its long-term efficacy needs further observation.

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.

Attenuation of Histone Methyltransferase KRYPTONITE-mediated transcriptional gene silencing by Geminivirus.

Although histone H3K9 methylation has been intensively studied in animals and a model plant Arabidopsis thaliana, little is known about the evolution of the histone methyltransferase and its roles in plant biotic stress response. Here we identified a Nicotiana benthamiana homolog of H3K9 histone methyltransferase KRYPTONITE (NbKYP) and demonstrated its fundamental roles on methylation of plant and virus, beside of leading to the suppression of endogenous gene expression and virus replication. NbKYP and another gene encoding DNA methyltransferase CHROMOMETHYLTRANSFERASE 3 (NbCMT3-1) were further identified as the key components of maintenance of transcriptional gene silencing, a DNA methylation involved anti-virus machinery. All three types of DNA methylations (asymmetric CHH and symmetric CHG/CG) were severely affected in NbKYP-silenced plants, but only severe reduction of CHG methylation found in NbCMT3-1-silenced plants. Attesting to the importance of plant histone H3K9 methylation immunity to virus, the virulence of geminiviruses requires virus-encoded trans-activator AC2 which inhibits the expression of KYP via activation of an EAR-motif-containing transcription repressor RAV2 (RELATED TO ABI3 and VP1). The reduction of KYP was correlated with virulence of various similar geminiviruses. These findings provide a novel mechanism of how virus trans-activates a plant endogenous anti-silencing machinery to gain high virulence.