Disruption of DNA-PKcs-mediated cGAS retention on damaged chromatin potentiates DNA damage-inducing agent-induced anti-multiple myeloma activity.

BACKGROUND: Targeting DNA damage repair factors, such as DNA-dependent protein kinase catalytic subunit (DNA-PKcs), may offer an opportunity for effective treatment of multiple myeloma (MM). In combination with DNA damage-inducing agents, this strategy has been shown to improve chemotherapies partially via activation of cGAS-STING pathway by an elevated level of cytosolic DNA. However, as cGAS is primarily sequestered by chromatin in the nucleus, it remains unclear how cGAS is released from chromatin and translocated into the cytoplasm upon DNA damage, leading to cGAS-STING activation. METHODS: We examined the role of DNA-PKcs inhibition on cGAS-STING-mediated MM chemosensitivity by performing mass spectrometry and mechanism study. RESULTS: Here, we found DNA-PKcs inhibition potentiated DNA damage-inducing agent doxorubicin-induced anti-MM effect by activating cGAS-STING signaling. The cGAS-STING activation in MM cells caused cell death partly via IRF3-NOXA-BAK axis and induced M1 polarization of macrophages. Moreover, this activation was not caused by defective classical non-homologous end joining (c-NHEJ). Instead, upon DNA damage induced by doxorubicin, inhibition of DNA-PKcs promoted cGAS release from cytoplasmic chromatin fragments and increased the amount of cytosolic cGAS and DNA, activating cGAS-STING. CONCLUSIONS: Inhibition of DNA-PKcs could improve the efficacy of doxorubicin in treatment of MM by de-sequestrating cGAS in damaged chromatin.

[Efficacy and Safety of Plerixafor Combined with G-CSF for Autologous Peripheral Blood Hematopoietic Stem Cell Mobilization in Lymphoma Patients].

OBJECTIVE: To investigate the efficacy and safety of plerixafor combined with granulocyte colony-stimulating factor (G-CSF) in mobilizing peripheral blood hematopoietic stem cells in patients with lymphoma. METHODS: The clinical data of lymphoma patients who received autologous hematopoietic stem cell mobilization using plerixafor combined with G-CSF from January 2019 to December 2021 were retrospectively analyzed. The patients received 3 kinds of mobilization regimens: front-line steady-state mobilization, preemptive intervention, and recuse mobilization. The acquisition success rate, excellent rate of collection, and incidence of treatment-related adverse reaction were counted. The influence of sex, age, disease remission status, bone marrow involvement at diagnosis, chemotherapy lines, number of chemotherapy, platelet count and number of CD34+ cells on the day before acquisition in peripheral blood on the collection results were analyzed to identify the risk factors associated with poor stem cell collection. RESULTS: A total of 43 patients with lymphoma were enrolled, including 7 cases who received front-line steady-state mobilization, 19 cases who received preemptive intervention, and 17 cases who received recuse mobilization. The overall acquisition success rate was 58.1% (25/43) after use of plerixafor combined with G-CSF, and acquisition success rate of front-line steady-state mobilization, preemptive intervention, and recuse mobilization was 100%, 57.9%(11/19), and 41.2%(7/17), respectively. The excellent rate of collection was 18.6%(8/43). A total of 15 patients experienced mild to moderate treatment-related adverse reactions. The number of CD34+ cells < 5 cells/µl in peripheral blood on the day before collection was an independent risk factor affecting stem cell collection. CONCLUSIONS: Plerixafor combined with G-CSF is a safe and effective mobilization regimen for patients with lymphoma. The number of CD34+ cells in peripheral blood on the day before collection is an predictable index for the evaluation of stem cell collection.

A novel Dmrt gene is specifically expressed in the testis of Chinese mitten crab, Eriocheir sinensis.

Dmrt is a family of genes related to the sexual regulators Doublesex of Drosophila melanogaster and Mab-3 of Caenorhabditis elegans. Dmrt genes are widely conserved and known for their involvement in sex determination and differentiation across phyla. In this study, we report here the identification of a novel Dmrt gene, named EsDmrt-like, from Chinese mitten crab Eriocheir sinensis. EsDmrt-like encodes a protein of 236 amino acids without intron. The protein contains a conserved DNA-binding DM domain that is characteristic of Dmrt genes. The DM domain shares 98% identity with that of Drosophila Dmrt99B and vertebrate Dmrt5, but outside the DM domain, there is little homology in sequence and no other conserved domain such as DMA specific to the Dmrt99B and Dmrt3-5. Interestingly, the expression pattern of EsDmrt-like is quite similar with that of vertebrate Dmrt1. Reverse transcription-polymerase chain reaction showed that EsDmrt-like transcripts were detectable only in testis with much higher expression at immature stage. In situ hybridization to gonad sections indicated that the EsDmrt-like mRNA was exclusively localized in Sertoli cells around the periphery of seminiferous tubules and developing germ cells including spermatogonium, spermatocyte, and spermatid, but absent in spermatozoa. This finding strongly suggests an essential role for EsDmrt-like in the male testicular development/differentiation of the crab.