1.Five Principles for the Development of Oncology Critical Care Medicine
Zhengheng YU ; Zeyu ZHANG ; Yanli YANG
Medical Journal of Peking Union Medical College Hospital 2026;17(1):10-15
With the deep integration of tumor diagnosis and treatment technologies and critical care medicine, oncology critical care has emerged as an innovative interdisciplinary field, whose standardized development is crucial for improving the prognosis of cancer patients. Based on complex system theory and incorporating cutting-edge clinical practices, this paper systematically elaborates on five core principles for promoting the high-quality development of oncology critical care: complex system thinking, value-based healthcare, interdisciplinary integration, spatiotemporal holism, and humanistic experience. These five principles provide a top-level design framework for the discipline in terms of conceptual understanding, comprehensive management, developmental paradigms, clinical treatment, and service models. They aim to establish a patient-centered oncology critical care system that balances medical quality and efficiency, ultimately maximizing patient survival benefits across their entire life cycle.
2.Mechanism of Number 2 Feibi Recipe in Ameliorating Pulmonary Fibrosis in Mice by Modulating Endoplasmic Reticulum Stress in AT2 Cells to Attenuate Apoptosis and Promote Alveolar Repair
Yaodong CAI ; Jialing BEI ; Wan WEI ; Chengyan XU ; Yanli LIU ; Yong WANG ; Yang JIAO ; Yun CHEN
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(10):80-92
ObjectiveTo investigate the intervention mechanism of the traditional Chinese medicine Number 2 Feibi recipe (N2FBR) in idiopathic pulmonary fibrosis (IPF), focusing on its effects on endoplasmic reticulum (ER) stress, apoptosis, stemness maintenance, and regenerative capacity of alveolar type Ⅱ epithelial cells (AT2 cells), and to validate the modern translational pathway of the theory of "deficiency of Zong Qi leading to pulmonary atelectasis and atrophy". MethodsA mouse model of pulmonary fibrosis was induced by bleomycin (BLM). Mice were randomly divided into blank control, model, low-, and high-dose N2FBR intervention groups (9.1, 18.2 g·kg-1), and prednisolone intervention group (6.5 mg·kg-1). Pulmonary histopathological changes and collagen deposition were evaluated using hematoxylin-eosin (HE) and Masson's trichrome staining. Hydroxyproline (HYP) content was measured by the alkaline hydrolysis method. Lung coefficient and pulmonary function parameters were evaluated. The mRNA expression levels of fibrosis-related factors, including collagen type Ⅰ alpha 1 chain (ColIa1), alpha-smooth muscle actin (α-SMA), and tissue inhibitor of metalloproteinase 1 (Timp1), were detected by real-time polymerase chain reaction (Real-time PCR). Cell apoptosis was assessed using the terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay. Apoptosis of AT2 cells was further evaluated by double immunofluorescence staining for surfactant protein C (SPC) and cysteine-aspartic protease-3 (Caspase-3). Endoplasmic reticulum (ER) stress in AT2 cells was examined by double staining for SPC and protein kinase R-like endoplasmic reticulum kinase (PERK). Ultrastructural changes of ER and lamellar bodies in AT2 cells were observed by transmission electron microscopy (TEM). The expression levels of key proteins involved in ER stress and apoptosis pathways, including PERK, activating transcription factor 4 (ATF4), and Caspase-3, were detected by Western blot. Double immunofluorescence staining of SPC and Ki-67 antigen (Ki-67) was performed to evaluate the proliferative capacity of AT2 cells. Lineage tracing technology (labeling AT2 cells with GFP) combined with Krt8 labeling was used to evaluate intermediate differentiation states, and morphological transformation of AT2 cells into alveolar type Ⅰ epithelial cells (AT1) was observed. ResultsBLM-induced mice exhibited significant structural disruption of lung tissue, increased collagen deposition, elevated lung coefficient, decreased pulmonary function, and upregulation of fibrosis-related factors (P<0.01). High-dose N2FBR treatment significantly ameliorated lung tissue damage and dysfunction, significantly reduced HYP content (P<0.01), and significantly downregulated ColIa1, α-SMA, and Timp1 expression (P<0.01). Apoptosis analysis showed increased TUNEL-positive and Caspase-3-positive AT2 cells in the model group, which was significantly reduced by high-dose N2FBR treatment. TEM revealed swollen ER structures in AT2 cells of the model group, which tended to return to normal following treatment. PERK protein staining analysis showed evident ER stress in AT2 cells of the model group, which were markedly alleviated in the treatment group. The expression levels of ER stress-related proteins PERK and ATF4, as well as the apoptosis-related protein Caspase-3, were elevated in the model group and significantly reduced after treatment. TEM also revealed disrupted lamellar body structures in the model group, which tended to recover in the treatment group. Regarding the proliferative capacity of AT2 cells, the proportion of Ki-67⁺SPC⁺ AT2 cells significantly increased in the treatment group (P<0.01). Lineage tracing showed that the proportion of keratin 8-positive green fluorescent protein-positive (Krt8⁺GFP⁺) cells increased in the model group, indicating differentiation arrest. This proportion was significantly reduced in the treatment group, and the morphology of GFP⁺ cells exhibited a flattened, extended shape, suggesting restored differentiation toward AT1 cells. ConclusionN2FBR alleviates ER stress in AT2 cells, reduces AT2 cell apoptosis, restores lamellar body structure and function, enhances proliferation activity, and alleviates differentiation arrest to promote differentiation into AT1 cells, thereby repairing the alveolar epithelium and effectively blocking the progression of pulmonary fibrosis. Its traditional Chinese medicine mechanism of "replenishing Zong Qi, harmonizing Qi and blood, and unblocking pulmonary meridians" closely aligns with the modern regulatory pathway of AT2 stem cells, providing a novel theoretical basis and experimental evidence for the intervention of IPF with traditional Chinese medicine.
3.Mechanism of Number 2 Feibi Recipe in Ameliorating Pulmonary Fibrosis in Mice by Modulating Endoplasmic Reticulum Stress in AT2 Cells to Attenuate Apoptosis and Promote Alveolar Repair
Yaodong CAI ; Jialing BEI ; Wan WEI ; Chengyan XU ; Yanli LIU ; Yong WANG ; Yang JIAO ; Yun CHEN
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(10):80-92
ObjectiveTo investigate the intervention mechanism of the traditional Chinese medicine Number 2 Feibi recipe (N2FBR) in idiopathic pulmonary fibrosis (IPF), focusing on its effects on endoplasmic reticulum (ER) stress, apoptosis, stemness maintenance, and regenerative capacity of alveolar type Ⅱ epithelial cells (AT2 cells), and to validate the modern translational pathway of the theory of "deficiency of Zong Qi leading to pulmonary atelectasis and atrophy". MethodsA mouse model of pulmonary fibrosis was induced by bleomycin (BLM). Mice were randomly divided into blank control, model, low-, and high-dose N2FBR intervention groups (9.1, 18.2 g·kg-1), and prednisolone intervention group (6.5 mg·kg-1). Pulmonary histopathological changes and collagen deposition were evaluated using hematoxylin-eosin (HE) and Masson's trichrome staining. Hydroxyproline (HYP) content was measured by the alkaline hydrolysis method. Lung coefficient and pulmonary function parameters were evaluated. The mRNA expression levels of fibrosis-related factors, including collagen type Ⅰ alpha 1 chain (ColIa1), alpha-smooth muscle actin (α-SMA), and tissue inhibitor of metalloproteinase 1 (Timp1), were detected by real-time polymerase chain reaction (Real-time PCR). Cell apoptosis was assessed using the terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay. Apoptosis of AT2 cells was further evaluated by double immunofluorescence staining for surfactant protein C (SPC) and cysteine-aspartic protease-3 (Caspase-3). Endoplasmic reticulum (ER) stress in AT2 cells was examined by double staining for SPC and protein kinase R-like endoplasmic reticulum kinase (PERK). Ultrastructural changes of ER and lamellar bodies in AT2 cells were observed by transmission electron microscopy (TEM). The expression levels of key proteins involved in ER stress and apoptosis pathways, including PERK, activating transcription factor 4 (ATF4), and Caspase-3, were detected by Western blot. Double immunofluorescence staining of SPC and Ki-67 antigen (Ki-67) was performed to evaluate the proliferative capacity of AT2 cells. Lineage tracing technology (labeling AT2 cells with GFP) combined with Krt8 labeling was used to evaluate intermediate differentiation states, and morphological transformation of AT2 cells into alveolar type Ⅰ epithelial cells (AT1) was observed. ResultsBLM-induced mice exhibited significant structural disruption of lung tissue, increased collagen deposition, elevated lung coefficient, decreased pulmonary function, and upregulation of fibrosis-related factors (P<0.01). High-dose N2FBR treatment significantly ameliorated lung tissue damage and dysfunction, significantly reduced HYP content (P<0.01), and significantly downregulated ColIa1, α-SMA, and Timp1 expression (P<0.01). Apoptosis analysis showed increased TUNEL-positive and Caspase-3-positive AT2 cells in the model group, which was significantly reduced by high-dose N2FBR treatment. TEM revealed swollen ER structures in AT2 cells of the model group, which tended to return to normal following treatment. PERK protein staining analysis showed evident ER stress in AT2 cells of the model group, which were markedly alleviated in the treatment group. The expression levels of ER stress-related proteins PERK and ATF4, as well as the apoptosis-related protein Caspase-3, were elevated in the model group and significantly reduced after treatment. TEM also revealed disrupted lamellar body structures in the model group, which tended to recover in the treatment group. Regarding the proliferative capacity of AT2 cells, the proportion of Ki-67⁺SPC⁺ AT2 cells significantly increased in the treatment group (P<0.01). Lineage tracing showed that the proportion of keratin 8-positive green fluorescent protein-positive (Krt8⁺GFP⁺) cells increased in the model group, indicating differentiation arrest. This proportion was significantly reduced in the treatment group, and the morphology of GFP⁺ cells exhibited a flattened, extended shape, suggesting restored differentiation toward AT1 cells. ConclusionN2FBR alleviates ER stress in AT2 cells, reduces AT2 cell apoptosis, restores lamellar body structure and function, enhances proliferation activity, and alleviates differentiation arrest to promote differentiation into AT1 cells, thereby repairing the alveolar epithelium and effectively blocking the progression of pulmonary fibrosis. Its traditional Chinese medicine mechanism of "replenishing Zong Qi, harmonizing Qi and blood, and unblocking pulmonary meridians" closely aligns with the modern regulatory pathway of AT2 stem cells, providing a novel theoretical basis and experimental evidence for the intervention of IPF with traditional Chinese medicine.
4.PD-L1 and TGF-β cooperatively regulate tumor immune escape: mechanisms and advances in dual-targeting therapy
Qianqian HE ; Yanli YANG ; Han ZHANG ; Zheyu CHEN ; Puzhong JI
Chinese Journal of Clinical Medicine 2026;33(3):533-543
While programmed cell death ligand 1 (PD-L1) inhibitors have yielded breakthroughs in tumor therapy, their efficacy is constrained by the heterogeneity of the tumor microenvironment and multiple immunosuppressive pathways. In recent years, research has revealed that transforming growth factor-β (TGF-β) synergistically drives tumor cell immune escape with PD-L1 via pathways such as metabolic reprogramming, epithelial-mesenchymal transition, and SOX family factors. Currently, various PD-L1/TGF-β bispecific antibodies (bsAbs) have exhibited promising therapeutic potential in early-phase clinical trials, yet they still confront challenges related to toxicity and drug resistance. This article systematically reviews the mechanisms by which PD-L1 and TGF-β synergistically regulate tumor immune escape, summarizes the clinical research progress of bsAbs, and discusses strategies for novel drug design and biomarker development, with the aim of offering new insights for the development of combined tumor immunotherapy strategies.
5.Current status and influencing factors of work readiness in patients returning to work after lung cancer surgery
Yuanyuan YIN ; Xingxia LONG ; Jie ZHANG ; Yanli, JI ; Ying ZHU ; Lijun HE ; Mei YANG
Chinese Journal of Clinical Thoracic and Cardiovascular Surgery 2026;33(07):1079-1084
Objective To investigate the current status of work readiness and its influencing factors among patients returning to work after lung cancer surgery. Methods A retrospective study was conducted on young and middle-aged postoperative lung cancer patients who were treated at the Department of Thoracic Surgery, West China Hospital, Sichuan University from March to September 2023 and returned to their jobs. Data were collected through a general information questionnaire, readiness for return-to-work scale (RRTW), general self-efficacy scale (GSES), and simplified coping style questionnaire (SCSQ). Univariate and multivariate logistic regression analyses were used to explore the factors affecting the work readiness of patients returning to work. Results A total of 219 patients were included, with 59 males and 160 females aged 18-60 years. Among the postoperative lung cancer patients returning to work, 73.1% were in the active maintenance stage of return-to-work readiness with a RRTW score of (17.59±1.48) points, and 26.9% were in the uncertain maintenance stage with a RRTW score of (16.22±1.50) points. Multivariate logistic regression analysis showed that patients aged≤30 years (OR=52.381), employees of enterprises and institutions (OR=7.682), agricultural, pastoral, fishery, forestry laborers (OR=15.665), positive coping (OR=5.043), those with higher self-efficacy (OR=1.157) and engaged in physically demanding work (OR=2.449) had higher return-to-work readiness, while patients with≥2 children (OR=0.055), self-payment (OR=0.044), and those working more than 40 hours per week (OR=0.122) had lower return-to-work readiness. Conclusion The return-to-work readiness of young and middle-aged postoperative lung cancer patients needs to be improved, and occupation, job nature, main coping styles, general self-efficacy and other factors are associated with return-to-work readiness.
6.Establishment and optimization of combined model of influenza and wind-heat syndrome in mice
Xiaoyan ZHANG ; Miao XIE ; Qishuai HU ; Xinxin FENG ; Yutao WANG ; Xin ZHAO ; Yanli LIANG ; Linyang CHEN ; Zifeng YANG
Acta Laboratorium Animalis Scientia Sinica 2025;33(8):1105-1115
Objective To establish a mouse model of H1N1 influenza wind-heat syndrome by combining climate intervention with influenza virus nasal drops.Methods Seventy-two BALB/c mice were divided randomly into nine groups:a Control group,wind-heat(FR)groups(FR-3Day,FR-5Day),and Model groups(1LD-3Day,2LD-3Day,3LD-3Day,1LD-5Day,2LD-5Day,2LD-5Day,3LD-5Day)(n=8 mice per group).Mice in the Control group were housed in a normal environment,while mice in the FR and Model groups were kept in wind-heat conditions for 7 d.Mice in the Model groups received nasal PR8 influenza virus infection on the 8th day,and mice in the Control and FR heat groups received equal amounts of physiological saline nasal drops.After virus challenge,each group was housed in a normal environment and samples were taken on days 3 and 5.The appearance of the mice was observed and recorded and the lung index,routine blood parameters,lung tissue pathology,serum interleukin(IL)-6 levels,and virus titers were detected in each group based on their behavioral status,stools,and body temperature.Results After 7 d of wind-heat intervention,mice in the FR groups showed no significant abnormalities in terms of appearance,stools,body temperature,routine blood parameters,or lung tissue pathology compared with the Control group.The appearance,lung index,red blood cell count,hemoglobin,hematocrit,pathological result,and body temperature in the Model groups worsened progressively with increasing time and toxin dosage,while the neutrophil percentage,lymphocyte percentage,virus titer,and serum IL-6 levels peaked on day 3 after viral attack,for the same viral dose,and then decreased slightly on day 5.Conclusions PR8 nasal drops and 7 d of wind-heat climate intervention can be used to establish a mouse model of influenza wind-heat syndrome.
7.Effects of treadmill exercise on hippocampal autophagy-induced apoptosis in ovariectomized stressed rats
Yanli SONG ; Xi ZHANG ; Yangbo GUO ; Xiaomei LING ; Linhai LI ; Zixin YANG ; Xiaoyun SU ; Jianmei CUI
Chinese Journal of Tissue Engineering Research 2025;29(18):3848-3855
BACKGROUND:Apoptosis and autophagy imbalance in the hippocampal region of perimenopausal depressed rats are closely related to cognitive decline.Whether aerobic exercise can reduce apoptosis by promoting hippocampal autophagy and thus improve the learning and memory abilities of perimenopausal depressed rats is not clear.OBJECTIVE:To investigate the possible mechanism by which 4-week moderate-intensity treadmill exercise improves learning memory ability in ovariectomized stressed rats.METHODS:Forty Sprague-Dawely rats were randomly divided into four groups,namely,sham operation group(n=10),ovariectomized group(n=10),ovariectomized stress group(n=10)and ovariectomized stress exercise group(n=10).Except for the sham operation group,the ovaries were removed in the other three groups to establish a perimenopausal rat model,and then a depressed rat model was established by chronic unpredictable stress in the latter two groups.The rats in the ovariectomized stress exercise group underwent a 4-week moderate-intensity treadmill exercise.Tail suspension test and sucrose preference test were performed to text depression-like behaviors in rats after exercise and stress.The eight-arm maze experiment was used to test the learning and memory behaviors of rats after exercise and stress.Western blot was used to detect the protein levels of AMP-activated protein kinase/UNC-51 like autophagy activating kinase 1/mammalian target of rapamycin(AMPK/mTOR/ULK1),hippocampus apoptotic factor Caspase-3 and the protein expression of autophagy markers LC-3II/Beclin-1 in the hippocampus.RESULTS AND CONCLUSION:(1)Compared with the sham operation group,rats in the ovariectomized and ovariectomized stress groups had prolonged resting time in the tail suspension test and decreased sugar-water intake and sugar-water preference in the sucrose preference test.(2)Ovary removal reduced the learning memory capacity of rats,as evidenced behaviorally by a significant increase in the number of working memory errors,the number of reference memory errors,and the completion time,and an even more pronounced increase in the above measures in the ovariectomized stress group.(3)Compared with the ovariectomized group,there was a significant reduction in the number of working memory errors,the number of reference memory errors,and the completion time in the ovariectomized stress group.(4)Compared with the sham operation group,in the ovariectomized and ovariectomized stress groups,the expression of hippocampal apoptotic factor Caspase 3 protein was significantly elevated,the expression of autophagy-related factors proteins Beclin-1 and LC3II,as well as the protein expression of AMPK and ULK1,was decreased,whereas the expression of mTOR protein was elevated.Changes in the above indicators were more significant in the ovariectomized stress group.(5)Compared with the ovariectomized stress group,in the ovariectomized stress exercise group,the protein expression of Caspase 3 was significantly decreased,the protein expression of Beclin-1 and LC3II was significantly increased,the protein expression of AMPK and ULK1 was significantly increased,and the protein expression of mTOR was significantly reduced.To conclude,4-week moderate-intensity treadmill exercise may promote cellular autophagy and reduce apoptosis through the AMPK/mTOR/ULK1 autophagy signaling pathway,thereby enhancing the learning and memory capacity of rats with ovariectomized depression
8.Value of a clinical diagnostic model of heart failure based on disulfidptosis-related genes
Sheng LI ; Xia CHEN ; Peiyao YANG ; Yanli GUO ; Li WANG ; Ketao MA
Chinese Journal of Geriatric Heart Brain and Vessel Diseases 2025;27(3):370-373
Objective To explore the value of a clinical diagnostic model of heart failure(HF)based on disulfidptosis-related genes.Methods The differentially expressed disulfidetosis-related genes from the training set of Gene Expression Omnibus Series(GSE)57345 were obtained,and then analyzed with Gene Ontology(GO),Kyoto Encyclopedia of Genes and Genomes(KEGG)en-richment analysis,and Metascape disease enrichment analysis.Six male C57BL/6J mice were ran-domly divided into control group(intraperitoneal injection of normal saline)and HF group(intra-peritoneal injection of isoproterenol),with 3 mice in each group.Real-time quantitative PCR was applied to detect the expression levels of key genes.Results GO enrichment analysis revealed that the differentially expressed disulfidetosis-related genes were mainly involved in platelet aggrega-tion and other aspects.KEGG showed they were significantly enriched in tight junctions,vascular smooth muscle contraction and other signaling pathways.Metascape enrichment analysis indicated that these genes were mainly related to focal glomerulosclerosis,glomerular disease,platelet dis-ease,tumor infiltration,nephrotic syndrome and other diseases.The HF group had significantly higher heart weight-to-body weight ratio,and lower ejection fraction,fractional shortening,cardiac output and stroke volume than the control group(P<0.05,P<0.01).The cardiac mRNA levels of BNP and MYH10 were significantly higher[1.026±0.501 vs 0.686±0.187,P=0.038;1.469(1.782,2.670)vs 0.360(0.786,1.117),P=0.000],while those of MYL6 and TLN1 was obviously lower(0.575±0.105 vs 1.000±0.202,P=0.027;0.429±0.114 vs 1.000±0.109,P=0.000)in the HF group than the control group.Conclusion Our constructed HF diagnostic model has better di-agnostic performance.
9.Effects of treadmill exercise on hippocampal autophagy-induced apoptosis in ovariectomized stressed rats
Yanli SONG ; Xi ZHANG ; Yangbo GUO ; Xiaomei LING ; Linhai LI ; Zixin YANG ; Xiaoyun SU ; Jianmei CUI
Chinese Journal of Tissue Engineering Research 2025;29(18):3848-3855
BACKGROUND:Apoptosis and autophagy imbalance in the hippocampal region of perimenopausal depressed rats are closely related to cognitive decline.Whether aerobic exercise can reduce apoptosis by promoting hippocampal autophagy and thus improve the learning and memory abilities of perimenopausal depressed rats is not clear.OBJECTIVE:To investigate the possible mechanism by which 4-week moderate-intensity treadmill exercise improves learning memory ability in ovariectomized stressed rats.METHODS:Forty Sprague-Dawely rats were randomly divided into four groups,namely,sham operation group(n=10),ovariectomized group(n=10),ovariectomized stress group(n=10)and ovariectomized stress exercise group(n=10).Except for the sham operation group,the ovaries were removed in the other three groups to establish a perimenopausal rat model,and then a depressed rat model was established by chronic unpredictable stress in the latter two groups.The rats in the ovariectomized stress exercise group underwent a 4-week moderate-intensity treadmill exercise.Tail suspension test and sucrose preference test were performed to text depression-like behaviors in rats after exercise and stress.The eight-arm maze experiment was used to test the learning and memory behaviors of rats after exercise and stress.Western blot was used to detect the protein levels of AMP-activated protein kinase/UNC-51 like autophagy activating kinase 1/mammalian target of rapamycin(AMPK/mTOR/ULK1),hippocampus apoptotic factor Caspase-3 and the protein expression of autophagy markers LC-3II/Beclin-1 in the hippocampus.RESULTS AND CONCLUSION:(1)Compared with the sham operation group,rats in the ovariectomized and ovariectomized stress groups had prolonged resting time in the tail suspension test and decreased sugar-water intake and sugar-water preference in the sucrose preference test.(2)Ovary removal reduced the learning memory capacity of rats,as evidenced behaviorally by a significant increase in the number of working memory errors,the number of reference memory errors,and the completion time,and an even more pronounced increase in the above measures in the ovariectomized stress group.(3)Compared with the ovariectomized group,there was a significant reduction in the number of working memory errors,the number of reference memory errors,and the completion time in the ovariectomized stress group.(4)Compared with the sham operation group,in the ovariectomized and ovariectomized stress groups,the expression of hippocampal apoptotic factor Caspase 3 protein was significantly elevated,the expression of autophagy-related factors proteins Beclin-1 and LC3II,as well as the protein expression of AMPK and ULK1,was decreased,whereas the expression of mTOR protein was elevated.Changes in the above indicators were more significant in the ovariectomized stress group.(5)Compared with the ovariectomized stress group,in the ovariectomized stress exercise group,the protein expression of Caspase 3 was significantly decreased,the protein expression of Beclin-1 and LC3II was significantly increased,the protein expression of AMPK and ULK1 was significantly increased,and the protein expression of mTOR was significantly reduced.To conclude,4-week moderate-intensity treadmill exercise may promote cellular autophagy and reduce apoptosis through the AMPK/mTOR/ULK1 autophagy signaling pathway,thereby enhancing the learning and memory capacity of rats with ovariectomized depression
10.Ubiquitination and degradation of RPTPα mediated by MARCH9
Yuqin ZHANG ; AIHEMAITI YILIXIATI ; Yanli WANG ; Zhi YANG ; Jian HUANG
Journal of Shanghai Jiaotong University(Medical Science) 2025;45(8):957-968
Objective·To investigate the molecular mechanisms and biological functions of the E3 ubiquitin ligase membrane-associated RING-CH 9(MARCH9)in regulating the ubiquitination of receptor protein tyrosine phosphatase alpha(RPTPα).Methods·Western blotting was employed to identify the ubiquitination type of RPTPα and to evaluate the regulatory effect of MARCH9 on its ubiquitination level;Comparative analysis of RPTPα protein stability was performed among wild-type MARCH9,catalytically inactive MARCH9 mutants(MARCH9 S198A or MARCH9-HC/CC),and endogenous MARCH9 knockdown via shRNA.Proteasome inhibitor MG132,autophagy inhibitor 3-MA,and lysosomal inhibitor chloroquine(CQ)were used to determine the degradation pathway of MARCH9-mediated RPTPα ubiquitination.The mechanism underlying 43℃heat shock-induced RPTPα degradation was explored.Stable lung cancer cell lines with MARCH9 single-knockdown(H1299-sh MARCH9)and MARCH9/RPTPα double-knockdown(H1299-sh MARCH9-sh RPTPα)were established using lentiviral vectors.CCK-8 proliferation assay,colony formation assay,and soft agar assay were conducted to evaluate the effects of MARCH9 or RPTPα on lung cancer cell proliferation and clonogenicity.Vasculogenic mimicry formation assay and scratch wound healing assay were performed to assess the impacts on tumor cell invasion and migration.Subcutaneous xenograft models in nude mice were established to examine in vivo tumorigenicity.Bioinformatics analysis was used to compare the expression differences and prognostic correlations of MARCH9 and RPTPα in lung cancer patients.Results·RPTPα predominantly underwent K63-linked poly-ubiquitination,which was significantly enhanced by MARCH9 overexpression.Wild-type MARCH9,but not its catalytic mutants,markedly reduced RPTPα protein stability,while endogenous MARCH9 knockdown increased RPTPα levels.CQ,not MG132 or 3-MA,restored RPTPα stability,indicating that MARCH9 mediated lysosomal degradation of RPTPα through ubiquitination.Heat shock at 43℃specifically enhanced MARCH9-RPTPα interaction,promoting RPTPα degradation.Functional assays revealed that,compared to control H1299 cells,MARCH9-knockdown cells exhibited elevated RPTPα levels,accelerated proliferation,enhanced clonogenicity and invasive capacity,and increased tumorigenicity in nude mice.These phenotypes could be reversed by double knockdown of MARCH9/RPTPα.Bioinformatics analysis demonstrated that high RPTPα expression correlated with poor prognosis and tumor metastasis in lung cancer patients,while MARCH9 showed inverse correlations.Conclusion·MARCH9 mediates K63-linked ubiquitination-dependent lysosomal degradation of phosphatase RPTPα,providing new insights into developing RPTPα-targeted cancer therapeutic strategies.

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