ABSTRACT
Histiocytic sarcoma (HS) is a rare hematological malignancy with limited treatment options, and it is also prone to complications such as hemophagocytic lymphohistiocytosis (HLH) in the later stages of the disease, leading to difficulties in treatment and poor prognosis. It highlights the importance of developing novel therapeutic agents. Herein, we present a case of a 45-year-old male patient who was diagnosed with PD-L1-positive HS with HLH. The patient was admitted to our hospital with recurrent high fever, multiple skin rashes with pruritus throughout the body and enlarged lymph nodes. Subsequently, pathological biopsy of the lymph nodes revealed high expression of CD163, CD68, S100, Lys and CD34 in the tumor cells and no expression of CD1a and CD207, confirming this rare clinical diagnosis. Concerning the low remission rate by conventional treatment in this disease, the patient was administered with sintilimab (an anti-programmed cell death 1 [anti-PD-1] monoclonal antibody) at 200 mg/d combined with a first-line chemotherapy regimen for one cycle. Further exploration of pathological biopsy by using next-generation gene sequencing led to the use of targeted therapy of chidamide. After one cycle of combination therapy (chidamide+sintilimab, abbreviated as CS), the patient achieved a favorable response. The patient showed remarkable improvement in the general symptoms and laboratory examination results (e.g., elevated indicators of inflammation); even the clinical benefits was not persistent, he survived one more month after his cessation of treatment by himself due to economic difficulty. Our case suggests that PD-1 inhibitor coupled with targeted therapy might constitute a potential therapeutic option for primary HS with HLH.
Subject(s)
Histiocytic Sarcoma , Lymphohistiocytosis, Hemophagocytic , Male , Humans , Middle Aged , Lymphohistiocytosis, Hemophagocytic/diagnosis , Lymphohistiocytosis, Hemophagocytic/drug therapy , Lymphohistiocytosis, Hemophagocytic/genetics , Histiocytic Sarcoma/diagnosis , Histiocytic Sarcoma/drug therapy , Histiocytic Sarcoma/genetics , Programmed Cell Death 1 Receptor , MutationABSTRACT
The choice of silage additives is an important factor for the storage of silage. One standard ensiling method and two enhanced ensiling methods (using natural silage, silage with mixed lactic acid bacteria, and silage with acetic acid, respectively) were carried out on Miscanthus sinensis. To determine the effects of these different methods, the biochemical methane potential (BMP) was determined. The results revealed that ensiling with acetic acid was the best method among the three ensiling methods. Acetic acid could quickly reduce the pH of the system to inhibit the growth of harmful bacteria. The rate of loss of dry matter was 0.92% when acetic acid was added, and the cumulative methane production was 149.6 mL·g-1 volatile solids. From an analysis of correlations between the properties and BMP of silage, the contents of acetic acid and total volatile fatty acids were significantly correlated with the BMP. This study provides a theoretical basis for improving the BMP of M. sinensis and achieving better effects of silage.
Subject(s)
Methane , Silage , Silage/analysis , Fermentation , Poaceae , Acetic AcidABSTRACT
The complete chloroplast genome sequence of Tulipa gesneriana L. was determined to investigate its phylogenetic position. This plastome is 151,958 base pairs (bp) in length, and comprises two inverted repeat (IRa and IRb) regions of 26,352 bp, a small single-copy region of 17,123 bp and a large single-copy region of 82,131 bp. The GC contents of the cp genome were 36.6%. In total, we annotated 126 genes including 81 protein-coding genes, 37 tRNA genes, and eight rRNA genes. Phylogenetic analysis based on nine chloroplast genomes indicates that T. gesneriana is closely related to T. iliensis and T. thianschanica.
ABSTRACT
Multiple myeloma is a plasma cell malignancy, accounting for approximately 1% of new cancer cases. It is the second most common hematological malignancy. Novel clinical agents such as the proteasome inhibitor-bortezomib, have shown improved survival rates in recent decades. However, multiple myeloma remains incurable, as most patients eventually relapse and become refractory to current treatments. Therefore, there is an urgent need for developing new regimens to overcome the bortezomib resistance. Here, we screened a library of 2370 bioactives and found that polyphyllin VII selectively suppressed multiple myeloma cell growth in vitro and in vivo. We identified moesin, one of the critical regulators of the Wnt/ß-catenin pathway, as a target of polyphyllin VII by drug affinity responsive target stability assay and cellular thermal shift assay. Polyphyllin VII binds to moesin and induces its degradation via the ubiquitin-proteasome pathway, thereby impairing the Wnt/ß-catenin pathway activity and leading to a reduction in the side population cells to overcome bortezomib resistance. Our study identified polyphyllin VII as a promising compound and moesin as a potential diagnostic and therapeutic target for treating multiple myeloma.
Subject(s)
Antineoplastic Agents , Multiple Myeloma , Antineoplastic Agents/pharmacology , Antineoplastic Agents/therapeutic use , Bortezomib/pharmacology , Bortezomib/therapeutic use , Cell Line, Tumor , Drug Resistance, Neoplasm , Humans , Microfilament Proteins , Multiple Myeloma/pathology , Neoplasm Recurrence, Local/drug therapy , Proteasome Inhibitors/pharmacology , Proteasome Inhibitors/therapeutic use , Saponins , beta Catenin/metabolismABSTRACT
OBJECTIVE: To investigate the efficacy of self-made arthroscopic single channel in the treatment of carpal tunnel syndrome. METHODS: Sixty patients with primary carpal tunnel syndrome treated from January 2014 to December 2019 were divided into arthroscopic group and traditional open operation group. There were 30 cases in arthroscopic group, including 12 males and 18 females, aged (47.5±4.5) years and the course of disease was (6.6±4.2) months. There were 30 cases in the traditional operation group, including 10 males and 20 females, aged (48.5±3.5) years, and the course of disease was (5.6±4.4) months. Both groups were unilateral. According to the anatomy of wrist joint and the characteristics of transverse carpal ligament and arthroscopy, the instruments including cannula, inner heart and hook knife were designed. The patients in two groups were treated with decompression of transverse carpal ligament using arthroscopy combined with self-made instruments and traditional open sergery. The incision length, operation time, intraoperative bleeding, hospitalization cost, hospitalization time and recovery time of the two groups were observed and compared. Boston Carpal Tunnel Questionnaire (BCTQ) score was used to evaluate the clinical efficacy of arthroscopy combined with self made instruments in the treatment of carpal tunnel syndrome. RESULTS: Compared with the traditional group, the arthroscopic group had significant advantages in incision length, operation time, intraoperative bleeding and hospital stay, but the total cost of hospitalization was increased. The Boston score was significantly higher in the arthroscopic group than that in the traditional group at 1 month after operation, but not at 3 and 6 months after operation. CONCLUSION: Arthroscopy combined with self-made instruments in the treatment of carpal tunnel syndrome is more reliable, minimally invasive and simplified than open surgery, but the patients should be clearly diagnosed and appropriately selected before operation to achieve satisfactory clinical effect.
Subject(s)
Carpal Tunnel Syndrome , Carpal Tunnel Syndrome/surgery , Decompression, Surgical , Female , Humans , Ligaments, Articular , Male , Treatment Outcome , Wrist/surgery , Wrist Joint/surgeryABSTRACT
Multiple myeloma (MM) is incurable and the second most common hematologic malignancy in plasma cells. Multiple myeloma stem cell-like cells (MMSCs), a rare population of MM cells, are believed to be the major cause of drug resistance and high recurrence rates in patients with MM. Therefore, developing novel strategies to eradicate MMSCs may favor myeloma treatment. In this study, based on the drug repositioning strategy, we found that albendazole (ABZ), a broad-spectrum antiparasitic drug, selectively suppresses the proliferation of multiple myeloma cells in vitro and in vivo and decreases number of aldehyde dehydrogenase (ALDH)-positive MMSCs in MM. Furthermore, RNA-seq of MM cells after ABZ treatment revealed that inhibition of the nuclear factor kappa-B (NF-κB) pathway is a key mediator of ABZ against MM. Moreover, we demonstrated that ABZ can resensitize cells resistant to bortezomib and overcome MMSCs-induced bortezomib resistance by decreasing ALDH1+ MMSCs numbers. Our findings provide preclinical evidence for utilizing the previously known pharmacologically active drug albendazole for the treatment of multiple myeloma.
Subject(s)
Albendazole/pharmacology , Bortezomib/pharmacology , Drug Resistance, Neoplasm/drug effects , Multiple Myeloma/drug therapy , Aldehyde Dehydrogenase 1 Family/genetics , Antineoplastic Combined Chemotherapy Protocols , Apoptosis/drug effects , Bortezomib/adverse effects , Cell Line, Tumor , Humans , Multiple Myeloma/genetics , NF-kappa B/genetics , Neoplastic Stem Cells/drug effects , RNA-Seq , Signal Transduction/drug effectsABSTRACT
It is not clear how Fms-like tyrosine kinase 3-internal tandem duplications (FLT3-ITD) regulates checkpoint kinase 1 (CHK1) in acute myeloid leukemia (AML). In this study, we investigated the regulatory effect of FLT3-ITD on CHK1. Our results showed that CHK1 was highly expressed in FLT3-ITD positive AML. The overall survival rate and disease-free survival rate of AML patients with high CHK1 level were lower than those of patients with low CHK1 level. Mechanistically, FLT3-ITD recruited p300 to the CHK1 promoter and subsequently acetylated H3K27, thereby enhancing the transcription of CHK1. Interfering with the expression of CHK1 significantly inhibited the cell proliferation and induced cell apoptosis in FLT3-ITD positive MV4-11 cells. In addition, CHK1 knockdown promoted the sensitivity of MV4-11 cells to the epigenetic inhibitors JQ1 and C646. This study discovers a new therapeutic target for FLT3-ITD + AML and provided evidence for the combination of epigenetic inhibitors for AML treatment.
Subject(s)
Checkpoint Kinase 1/metabolism , Gene Duplication/genetics , Leukemia, Myeloid, Acute/enzymology , Tandem Repeat Sequences/genetics , fms-Like Tyrosine Kinase 3/genetics , Adolescent , Adult , Aged , Apoptosis , Blotting, Western , Chromatin Immunoprecipitation , Enzyme Activation , Epigenesis, Genetic/genetics , Female , Humans , Leukemia, Myeloid, Acute/metabolism , Male , Middle Aged , Young Adult , fms-Like Tyrosine Kinase 3/metabolismABSTRACT
BACKGROUND: T-cell acute lymphoblastic leukemia (T-ALL) is a malignant tumor of the hematopoietic system, which can develop at any age, with the symptoms of weakness, fatigue, enlarged lymph nodes, or weight loss. Nuclear paraspeckle assembly transcript 1 (NEAT1) is involved in the process of T-ALL, but the regulatory mechanism is still not known clearly. METHODS: The expression levels of NEAT1 and miR-146b-5p in T-ALL cells were performed by qRT-PCR and NOTCH1 protein level- wwWwas determined by western blot assay. Dual-luciferase reporter assay was used to detect the interaction between NEAT1 and miR-146b-5p, as well as miR-146b-5p and NOTCH1. The cell proliferation was measured by using MTT assay and colony formation assay. RESULTS: The expression levels of NEAT1 were markedly increased, but miR-146b-5p levels were reduced in T-ALL cells. Knockdown of NEAT1 or overexpression of miR-146b-5p decreased NOTCH1 expression, inhibited the proliferation of T-ALL cells. MiR-146b-5p bound both NEAT1 and NOTCH1 3'-UTR directly. Finally, inhibition of miR-146b-5p could abrogate the effects of NEAT1 knockdown on the proliferation of T-ALL cells. CONCLUSION: NEAT1 promotes the proliferation of T-ALL cells by sponging miR-146b-5p to upregulate the expression of NOTCH1. The results of this study provide new insight into the action mechanism of NEAT1 modulating T-ALL progression.
Subject(s)
Cell Proliferation/physiology , MicroRNAs/metabolism , Precursor T-Cell Lymphoblastic Leukemia-Lymphoma/pathology , RNA, Long Noncoding/metabolism , Receptor, Notch1/metabolism , Signal Transduction/physiology , Bone Marrow/metabolism , Bone Marrow/pathology , Disease Progression , Female , Gene Expression Regulation, Neoplastic , Humans , Male , Middle Aged , Precursor T-Cell Lymphoblastic Leukemia-Lymphoma/metabolismABSTRACT
OBJECTIVE: To investigate the clinical effect of precise puncture and low-dose bone cement in percutaneous vertebroplasty (PVP). METHODS: Sixty patients with osteoporotic vertebral compression fracture (OVCFs) who were treated with PVP in our hospital from July 2018 to June 2019. These included patients were divided into group A (N = 30) and group B (N = 30). Group A has punctured to the fracture area accurately and injected with a small dose of bone cement, the group B was injected with a conventional dose of bone cement. The operation time, the amount of bone cement injection, the number of X-rays, the VAS scores, the leakage rate of bone cement, and the incidence of adjacent vertebral fractures were compared between the two groups. RESULT: The operation time, fluoroscopic times, and bone cement volume in group A are less than that in group B (P < 0.05). Patients in group A had a lower incidence of cement leakage and adjacent vertebral fracture than that in patients in group B. There was no significant difference in postoperative pain relief between the two groups. CONCLUSIONS: Precise puncture and injection of small doses of bone cement can reduce the number of X-ray fluoroscopy, operation time, amount of bone cement injection, reduce the rate of bone cement leakage and the incidence of adjacent vertebral fractures, which is a safe and effective surgical approach for the treatment for the aged with OVCFs.
Subject(s)
Bone Cements , Fractures, Compression/etiology , Fractures, Compression/surgery , Osteoporosis/complications , Spinal Fractures/surgery , Vertebroplasty/methods , Age Factors , Aged , Aged, 80 and over , Bone Cements/adverse effects , Female , Fluoroscopy , Fractures, Compression/diagnostic imaging , Humans , Male , Operative Time , Osteoporosis/diagnostic imaging , Pain, Postoperative/epidemiology , Pain, Postoperative/etiology , Pain, Postoperative/prevention & control , Safety , Spinal Puncture/methods , Treatment Outcome , Vertebroplasty/adverse effectsABSTRACT
BACKGROUND: T-cell acute lymphoblastic leukemia (T-ALL) is an uncommon and aggressive subtype of acute lymphoblastic leukemia (ALL). In the serum of T-ALL patients, the activity of lactate dehydrogenase A (LDHA) is increased. We proposed that targeting LDHA may be a potential strategy to improve T-ALL outcomes. The current study was conducted to investigate the antileukemic effect of LDHA gene-targeting treatment on T-ALL and the underlying molecular mechanism. METHODS: Primary T-ALL cell lines Jurkat and DU528 were treated with the LDH inhibitor oxamate. MTT, colony formation, apoptosis, and cell cycle assays were performed to investigate the effects of oxamate on T-ALL cells. Quantitative real-time PCR (qPCR) and Western blotting analyses were applied to determine the related signaling pathways. A mitochondrial reactive oxygen species (ROS) assay was performed to evaluate ROS production after T-ALL cells were treated with oxamate. A T-ALL transgenic zebrafish model with LDHA gene knockdown was established using CRISPR/Cas9 gene-editing technology, and then TUNEL, Western blotting, and T-ALL tumor progression analyses were conducted to investigate the effects of LDHA gene knockdown on T-ALL transgenic zebrafish. RESULTS: Oxamate significantly inhibited proliferation and induced apoptosis of Jurkat and DU528 cells. It also arrested Jurkat and DU528 cells in G0/G1 phase and stimulated ROS production (all P < 0.001). Blocking LDHA significantly decreased the gene and protein expression of c-Myc, as well as the levels of phosphorylated serine/threonine kinase (AKT) and glycogen synthase kinase 3 beta (GSK-3ß) in the phosphatidylinositol 3'-kinase (PI3K) signaling pathway. LDHA gene knockdown delayed disease progression and down-regulated c-Myc mRNA and protein expression in T-ALL transgenic zebrafish. CONCLUSION: Targeting LDHA exerted an antileukemic effect on T-ALL, representing a potential strategy for T-ALL treatment.
Subject(s)
Lactate Dehydrogenase 5/genetics , Precursor T-Cell Lymphoblastic Leukemia-Lymphoma , Adult , Animals , Animals, Genetically Modified , Female , Gene Knockdown Techniques , Glycogen Synthase Kinase 3 beta , Humans , Jurkat Cells , Male , Oxamic Acid/pharmacology , Phosphatidylinositol 3-Kinases , Precursor T-Cell Lymphoblastic Leukemia-Lymphoma/genetics , Proto-Oncogene Proteins c-akt , Proto-Oncogene Proteins c-myc , Signal Transduction , T-Lymphocytes , ZebrafishABSTRACT
The accurate analysis of single-nucleotide polymorphisms is of great significance for clinical detection and diagnosis. Based on the hybridization hindrance caused by graphene oxide (GO) and hairpin probe, we report a T7 Exo-assisted cyclic amplification technique to distinguish single-base mismatch for highly sensitive and selective detection of mutant-type DNA. When the mutant-type target is completely complementary to the probe, the T7 Exo hydrolyzes the probe and releases the fluorescent molecule from the GO surface, resulting in a fluorescence signal. Conversely, when the wild-type mismatch target is present, the weak hybridization prevents the release of FAM-labeled probe from the GO surface. Therefore, the FAM-labeled probe cannot be degraded efficiently by T7 Exo, and the fluorescence is still quenched by GO. The detection limit of the proposed method can be as low as 34 fM due to the cyclic signal amplification. The experimental results showed that the established method could be used to detect single-nucleotide polymorphisms accurately and sensitively at low cost.
Subject(s)
DNA Probes/chemistry , Exodeoxyribonucleases/chemistry , Graphite/chemistry , Electrophoresis, Polyacrylamide Gel , Feasibility Studies , Fluorescent Dyes/chemistry , HeLa Cells , Humans , Limit of Detection , Mutation , Nucleic Acid Hybridization , Polymorphism, Single Nucleotide , fms-Like Tyrosine Kinase 3/geneticsABSTRACT
The present study was designed to explore the biological role of resveratrol (RES) in rheumatoid arthritis (RA) and the underlying mechanism. The adjuvant-induced arthritic rats were administered RES on the 12th day after model establishment, and then arthritis assessment, oxidative stress measurement, histological examination, and immunohistochemical staining were performed. The primary rat fibroblast-like synoviocytes (FLS) were isolated and treated with RES in vitro and then cell proliferation and apoptosis assay were examined. Chromatin immunoprecipitation assay, luciferase reporter assay, intracellular reactive oxygen species (ROS) determination, western blot, and quantitative real time-polymerase chain reaction (qRT-PCR) were performed to investigate the mechanisms. RES administration decreased arthritis scores and serum levels of antioxidant enzymes, attenuated paw swelling, synovial hyperplasia, inflammatory cell infiltration, and cartilage degradation, as well as inhibited synoviocyte proliferation in synovial tissues. Further investigation indicated that RES inhibited ROS production and FLS proliferation through activating the silent information regulator 1 (SIRT1)/nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway. NF-κB was confirmed to negatively regulate miR-29a-3p and miR-23a-3p expression by directly binding to its promoter. Mechanistic analyses further revealed that Kelch-like erythroid cell-derived protein with CNC homology (ECH)-associated protein 1 (Keap1), a negative regulator of Nrf2, was a downstream target of miR-29a-3p, while miR-23a-3p directly targeted cullin3 (cul3), a master regulator of ubiquitination and degradation of Nrf2. Together, the present study provided evidence that RES ameliorated RA through activation of Nrf2-ARE signaling pathway via SIRT1/NF-κB/miR-29a-3p/Keap1 and SIRT1/NF-κB/miR-23a-3p/cul3 signaling pathway.
Subject(s)
Antioxidants/pharmacology , Arthritis, Rheumatoid/drug therapy , NF-E2-Related Factor 2/drug effects , Resveratrol/pharmacology , Sirtuin 1/drug effects , Animals , Apoptosis/drug effects , Cell Proliferation/drug effects , Disease Models, Animal , Male , Rats , Rats, Sprague-Dawley , Signal Transduction/drug effectsABSTRACT
OBJECTIVE: To investigate the short term clinical efficacy of direct anterior approach(DAA) total hip arthroplasty for the treatment of ankylosing spondylitis with hip flexion deformity. METHODS: From September 2014 to June 2017, 15 cases of ankylosing spondylitis with flexion deformity of the hip were treated with total hip arthroplasty through DAA approach including 12 males(17 hips) and 3 females(4 hips) with an average age of 34.4 years old ranging from 21 to 57 years old. Harris score system was used before and after operation to evaluate hip function, total hip activity and visual analogue scale (VAS) were used to evaluate the clinical efficacy. RESULTS: All 15 patients were followed up for an average of 26.2 months. In the operation, 1 case of great trochanter avulsion was given wire binding, and 1 case of linear split of the femur were given by wire binding. There were no hematoma, nerve injury and deep vein thrombosis of lower extremity. No prosthesis loosening and sinking were observed in the follow-up of X-ray film after operation. There was no heterotopic ossification after operation. After operation, 18 hips pain were relieved completely, and 3 hips pain were found when walking, which all satisfied with the daily life self-care requirements. Harris hip score, total hip motion and VAS score at 1 week after operation were significantly different from those before operation(P<0.05). There was no significant difference in the scores of HHS, total hip motion and VAS at 1, 6 months after operation(P>0.05). At the final follow-up, the Harris score was 91.2±5.3, the total hip mobility was (217.1±29.7)°, and the postoperative VAS pain score was 1.2±0.5, which was significantly different from the preoperative score(P<0.05). CONCLUSIONS: DAA approach THA has good effect in treating AS hip nonfunctional ankylosis with less trauma, less pain and quick recovery. It has a good short term effect, which can effectively improve the quality of life of patients.
Subject(s)
Arthroplasty, Replacement, Hip , Hip Prosthesis , Spondylitis, Ankylosing , Adult , Antiviral Agents , Female , Hepatitis C, Chronic , Hip Joint , Humans , Male , Middle Aged , Quality of Life , Range of Motion, Articular , Retrospective Studies , Treatment Outcome , Young AdultABSTRACT
OBJECTIVE: To compare the clinical efficacy of total arthroscopic surgery and traditional surgery for popliteal cyst. METHODS: From August 2014 to July 2017, 60 cases of popliteal cyst were treated with total arthroscopy or traditional surgery respectively. In total arthroscopy group, there were 30 patients including 7 males and 23 females with an average age of (55.81±8.53) years old; the duration of the disease was (3.52±1.12) years;according to Rauschning-Lingdgren grading, 7 cases were grade I, 19 cases were grade II, 4 cases were grade III. In traditional surgical group, there were 30 patients including 5 males and 25 females with an average age of (57.93±9.84) years old; the duration of the disease was (3.48±1.34) years; according to Rauschning-Lingdgren grading, 5 cases were grade I, 21 cases were grade II, 4 cases were grade III. Preoperative symptoms involved such as arthralgia and swelling after knee joint and limited mobility. MRI confirmed a popliteal cyst. Arthroscopic surgery and traditional surgical was used respectively. Incision length, operation time, average stay, total hospital cost and Lysholm score of two groups were compared. RESULTS: In the total arthroscopic group, 1 case suffered from nerve injury, and all cases' incision healed well. In the traditional surgical group, there was 1 case of incision infection, 2 cases of poor healing, 1 case of nerve injury and 1 case of recurrence. All 60 cases were followed up for 6 to 30 months with an average of (13.3±6.5) months. After operation, the symptoms of knee joint arthralgia and swelling, discomfort were significantly improved in the two groups. There were statistically significant differences in incision length, operation time, average stay, total hospitalcost and Lysholm score 6 months after surgery(P<0.05). CONCLUSIONS: The total arthroscopic resection of popliteal cyst, via anterior approach to having a knee joint cavity exploration and treatment of meniscus and bursa, while combined with posteromedial approach for cyst excision would promise a minimal surgery and less pain for patients. Patients will have a rapider recovery, lower recurrence rate and less complication. The total arthroscopic resection easy to accepting for the patient and having a better clinical curative effect is obviously superior to the traditional surgery.
Subject(s)
Popliteal Cyst , Aged , Arthroscopy , Bursa, Synovial , Female , Humans , Knee Joint , Male , Middle Aged , Neoplasm Recurrence, Local , Treatment OutcomeABSTRACT
Although the kinase CHK1 is a key player in the DNA damage response (DDR), several studies have recently provided evidence of DDR-independent roles of CHK1, in particular following phosphorylation of its S280 residue. Here, we demonstrate that CHK1 S280 phosphorylation is cell cycle-dependent and peaks during mitosis. We found that this phosphorylation was catalyzed by the kinase PIM2, whose protein expression was also increased during mitosis. Importantly, we identified polo-like kinase 1 (PLK1) as a direct target of CHK1 during mitosis. Genetic or pharmacological inhibition of CHK1 reduced the activating phosphorylation of PLK1 on T210, and recombinant CHK1 was able to phosphorylate T210 of PLK1 in vitro Accordingly, S280-phosphorylated CHK1 and PLK1 exhibited similar specific mitotic localizations, and PLK1 was co-immunoprecipitated with S280-phosphorylated CHK1 from mitotic cell extracts. Moreover, CHK1-mediated phosphorylation of PLK1 was dependent on S280 phosphorylation by PIM2. Inhibition of PIM proteins reduced cell proliferation and mitotic entry, which was rescued by expressing a T210D phosphomimetic mutant of PLK1. Altogether, these data identify a new PIM-CHK1-PLK1 phosphorylation cascade that regulates different mitotic steps independently of the CHK1 DDR function.This article has an associated First Person interview with the first author of the paper.
Subject(s)
Cell Cycle Proteins/metabolism , Checkpoint Kinase 1/metabolism , Mitosis/physiology , Protein Serine-Threonine Kinases/metabolism , Proto-Oncogene Proteins/metabolism , Animals , Cell Cycle/genetics , Cell Cycle/physiology , Cell Cycle Proteins/genetics , Cell Line, Tumor , Checkpoint Kinase 1/genetics , DNA Damage/genetics , DNA Damage/physiology , HeLa Cells , Humans , Mice, Knockout , Mitosis/genetics , Phosphorylation/genetics , Phosphorylation/physiology , Polymerase Chain Reaction , Protein Serine-Threonine Kinases/genetics , Proto-Oncogene Proteins/genetics , Signal Transduction/genetics , Signal Transduction/physiology , Tandem Mass Spectrometry , Polo-Like Kinase 1ABSTRACT
We investigated cell cycle regulation in acute myeloid leukemia cells expressing the FLT3-ITD mutated tyrosine kinase receptor, an underexplored field in this disease. Upon FLT3 inhibition, CDC25A mRNA and protein were rapidly down-regulated, while levels of other cell cycle proteins remained unchanged. This regulation was dependent on STAT5, arguing for FLT3-ITD-dependent transcriptional regulation of CDC25A. CDC25 inhibitors triggered proliferation arrest and cell death of FLT3-ITD as well as FLT3-ITD/TKD AC-220 resistant cells, but not of FLT3-wt cells. Consistently, RNA interference-mediated knock-down of CDC25A reduced the proliferation of FLT3-ITD cell lines. Finally, the clonogenic capacity of primary FLT3-ITD AML cells was reduced by the CDC25 inhibitor IRC-083864, while FLT3-wt AML and normal CD34+ myeloid cells were unaffected. In good agreement, in a cohort of 100 samples from AML patients with intermediate-risk cytogenetics, high levels of CDC25A mRNA were predictive of higher clonogenic potential in FLT3-ITD+ samples, not in FLT3-wt ones.Importantly, pharmacological inhibition as well as RNA interference-mediated knock-down of CDC25A also induced monocytic differentiation of FLT3-ITD positive cells, as judged by cell surface markers expression, morphological modifications, and C/EBPα phosphorylation. CDC25 inhibition also re-induced monocytic differentiation in primary AML blasts carrying the FLT3-ITD mutation, but not in blasts expressing wild type FLT3. Altogether, these data identify CDC25A as an early cell cycle transducer of FLT3-ITD oncogenic signaling, and as a promising target to inhibit proliferation and re-induce differentiation of FLT3-ITD AML cells.