HDAC7, a member of class IIa HDACs, plays a pivotal regulatory role in tumor, immune, fibrosis, and angiogenesis, rendering it a potential therapeutic target. Nevertheless, due to the high similarity in the enzyme active sites of class IIa HDACs, inhibitors encounter challenges in discerning differences among them. Furthermore, the substitution of key residue in the active pocket of class IIa HDACs renders them pseudo-enzymes, leading to a limited impact of enzymatic inhibitors on their function. In this study, proteolysis targeting chimera (PROTAC) technology was employed to develop HDAC7 drugs. We developed an exceedingly selective HDAC7 PROTAC degrader B14 which showcased superior inhibitory effects on cell proliferation compared to TMP269 in various diffuse large B cell lymphoma (DLBCL) and acute myeloid leukemia (AML) cells. Subsequent investigations unveiled that B14 disrupts BCL6 forming a transcriptional inhibition complex by degrading HDAC7, thereby exerting proliferative inhibition in DLBCL. Our study broadened the understanding of the non-enzymatic functions of HDAC7 and underscored the importance of HDAC7 in the treatment of hematologic malignancies, particularly in DLBCL and AML.

Objective:To observe multiple locus variable-number tandem repeat analysis (MLVA) typing of Brucella isolated from Himalayan marmot in Qinghai-Tibet Plateau of Qinghai Province, and to explore the relationship between the strains and strains previous isolated from Qinghai Province. Methods:Blood samples of Himalayan marmot were collected in Qinghai-Tibet Plateau of Qinghai Province from March 2019 to October 2020. Pathogens were isolated and cultured from Brucella antibody positive samples identified by using the rose bengal test (RBT). Conventional biological methods and molecular biological methods (BCSP31-PCR and AMOS-PCR) were used for strain identification. At the same time, MLVA method was used to genotype the isolated strains, and cluster analysis was used to analyze the genetic relationships between the strains based on the genotype of 70 Brucella isolated from different hosts in Qinghai Province. Results:A total of 1 466 blood samples of Himalayan marmot were collected from Qinghai-Tibet Plateau. Two strains of Brucella were isolated and cultured from 64 RBT-positive samples, named QH2013054 and QH2013062, respectively. They were identified as Brucella ovis biotype Ⅲ by conventional and molecular biological methods. The MLVA genotyping results showed that QH2013054 and QH2013062 were different at the Bru16 locus, indicating different MLVA genotypes. Cluster analysis showed that strain QH2013054 had the same MLVA genotype as 7 strains, among which 6 strains were from 3 farmers and 3 sheep from the same family in Gonghe County, and 1 strain was from a farmer in Menyuan Hui Autonomous County. The strain QH2013062 had the same MLVA genotype as 4 strains, including 3 strains from 3 farmers in Menyuan Hui Autonomous County and 1 strain from a farmer in Tu Autonomous County of Huzhu. Conclusions:The strains of Brucella isolated from Himalayan marmot in Qinghai-Tibet Plateau of Qinghai Province have the same MLVA genotype as some strains of Brucella isolated from humans and sheep in Qinghai Province. It is speculated that the host humans, sheep and Himalayan marmot in Qinghai-Tibet Plateau may have a common source of infection.