Objective:To investigate the effect of early high-sucrose diet (eHSD) on cognitive function and its regulatory mechanism in 3×Tg-AD mice.Methods:(1) Eighteen specific-pathogen-free (SPF)-grade 2-month-old wide-type (WT) mice were randomly divided into a WT+normal chow diet (NCD) group and a WT+eHSD group, with 9 mice in each group; and 18 SPF-grade 2-month-old 3×Tg-AD mice were randomly divided into a 3×Tg-AD+NCD group and a 3×Tg-AD+eHSD group, with 9 mice in each group. At 2-5 months old, mice in the 4 groups received standard laboratory food+purified water or 30% sucrose water, followed by standard feed for all groups. At 8 months old, cognitive function was assessed by Morris water maze test; fluorescent intensity of AT8 (phosphorylated [p]-tau) and T22 (tau oligomers) in the hippocampal tissues was detected by immunofluorescent staining; concentrations of β-amyloid protein (Aβ) 42 and Aβ 40 were detected by enzyme-linked immunosorbent assay (ELISA); protein expressions of stimulator of interferon genes (STING), TANK-binding kinase 1 (TBK1), p-TBK1, and CCAAT/enhancer-binding protein β (C/EBPβ) were detected by Western blotting; activity of C/EBPβ transcription factor was detected by activity assay; mitochondrial DNA (mtDNA) content in the cytoplasm of cell was detected by real-time quantitative PCR (qPCR). (2) Eighteen SPF-grade 2-month-old 3×Tg-AD mice were randomized into a 3×Tg-AD+eHSD+H-151 group and a 3×Tg-AD+eHSD+dimethyl sulfoxide (DMSO) group, with 9 mice in each group. Mice at 2-5 months old were given standard laboratory food+30% sucrose water; they were, respectively, injected intraperitoneally with STING pathway inhibitor H-151 or DMSO at 5 months old, and continually injected until 8 months old; and then, the behavioral testing, immunofluorescent staining, ELISA, Western blotting and C/EBPβ transcription factor activity experiments were repeated as before. (3) After crossing C/EBPβ heterozygous knockout (C/EBPβ +/-) mice with 3×Tg-AD mice, 3×Tg-AD/C/EBPβ +/- mice were obtained, and 3×Tg-AD mice were used as controls; they were named 3×Tg-AD/C/EBPβ +/-+eHSD group and 3×Tg-AD+eHSD group, with 9 mice in each group. Both groups of mice were given standard laboratory food+30% sucrose water at 2-5 months old, followed by standard feed until 8 months old; and then, the behavioral testing, immunofluorescent staining, ELISA, and Western blotting experiments were repeated as before. (4) C/EBPβ transgenic mice (C/EBPβTg) were crossed with 3×Tg-AD mice to obtain C/EBPβTg/3×Tg-AD mice, and Non-Tg/3×Tg-AD mice were used as controls; they were, respectively, named as C/EBPβTg/3×Tg-AD+eHSD+H-151 group, Non-Tg/3×Tg-AD+eHSD+H-151 group, and Non-Tg/3×Tg-AD+eHSD+DMSO group, with 9 mice in each group. All 3 groups of mice were given standard laboratory food+30% sucrose water at 2-5 months old; at 5-8 months old, mice in the C/EBPβTg/3×Tg-AD+eHSD+H-151 group and Non-Tg/3×Tg-AD+eHSD+H-151 group were intraperitoneally injected with H-151, while mice in the Non-Tg/3×Tg-AD+eHSD+DMSO group were injected with DMSO; and then, the behavioral testing, immunofluorescent staining, ELISA, and Western blotting experiments were repeated as before. Results:(1) Compared with those in the WT+NCD group and WT+eHSD group, area under the latency curve of 3×Tg-AD+eHSD mice was significantly increased, and proportion of time spending in the targeted quadrant of mice in the 3×Tg-AD+NCD group and 3×Tg-AD+eHSD group was significantly decreased ( P<0.05); compared with that in the 3×Tg-AD+NCD group, proportion of time spending in the targeted quadrant in mice of the 3×Tg-AD+eHSD group was significantly reduced ( P<0.05). Compared with the 3×Tg-AD+NCD group, the 3×Tg-AD+eHSD group had significantly increased p-tau and tau oligomers, Aβ 42 and Aβ 40 concentrations in the hippocampus (AT8 fluorescent intensity: 1.000±0.076 vs. 2.902±0.399; T22 fluorescent intensity: 1.000±0.145 vs. 2.495±0.273; Aβ 42: 1.000±0.167 vs.1.956±0.132; Aβ 40: 1.000±0.226 vs.1.900±0.116), significantly increased C/EBPβ protein expression and C/EBPβ transcription factor activity (1.000±0.164 vs. 1.804±0.112; 1.000±0.216 vs. 2.743±0.301), and statistically increased mtDNA level detected by D-loop1 and D-loop3 (1.000±0.234 vs. 2.800±0.210; 1.000±0.155 vs. 2.952±0.078; P<0.05). Compared with the 3×Tg-AD+NCD group, the 3×Tg-AD+eHSD group had significantly increased STING protein expression and p-TBK1/TBK1 ratio (STING: 1.000±0.192 vs. 2.093±0.081; p-TBK1/TBK1: 1.000±0.148 vs. 1.561±0.112, P<0.05). (2) Compared with the 3×Tg-AD+eHSD+DMSO group, the 3×Tg-AD+eHSD+H-151 group had significantly decreased area under the latency curve, significantly increased proportion of time spending in the targeted quadrant, significantly decreased p-tau and tau oligomers expressions, Aβ 42 and Aβ 40 concentrations in the hippocampus (AT8 fluorescent intensity: 1.000±0.142 vs. 0.538±0.057; T22 fluorescent intensity: 1.000±0.104 vs. 0.665±0.088; Aβ 42: 1.000±0.084 vs. 0.600±0.007; Aβ 40: 1.000±0.138 vs. 0.476±0.083), significantly decreased STING protein expression and p-TBK1/TBK1 ratio (STING: 1.000±0.054 vs. 0.468±0.111; p-TBK1/TBK1: 1.000±0.057 vs. 0.598±0.090), and significantly decreased C/EBPβ transcription factor activity (1.000±0.097 vs. 0.445±0.106; P<0.05). (3) Compared with the 3×Tg-AD+eHSD group, the 3×Tg-AD/C/EBPβ +/-+eHSD group had significantly decreased area under the latency curve, significantly increased proportion of time spending in the targeted quadrant, significantly decreased p-tau and tau oligomers, Aβ 42 and Aβ 40 concentrations in the hippocampus (AT8 fluorescent intensity: 1.000±0.160 vs. 0.506±0.065; T22 fluorescent intensity: 1.000±0.127 vs. 0.346±0.048; Aβ 42: 1.000±0.017 vs. 0.510±0.101; Aβ 40: 1.000±0.098 vs. 0.586±0.153), and significantly decreased C/EBPβ protein expression (1.000±0.101 vs. 0.568±0.094; P<0.05). (4) Compared with the Non-Tg/3×Tg-AD+eHSD+DMSO group, the Non-Tg/3×Tg-AD+eHSD+H-151 group had significantly decreased area under the latency curve, significantly increased proportion of time spending in the targeted quadrant, and significantly decreased p-tau and tau oligomers expressions, Aβ 40 concentration in the hippocampus, and the Non-Tg/3×Tg-AD+eHSD+H-151 group, the C/EBPβTg/3×Tg-AD+eHSD+H-151 group had significantly decreased STING protein expression and p-TBK1/TBK1 ratio in the hippocampus ( P<0.05). Compared with the Non-Tg/3×Tg-AD+eHSD+H-151 group, the C/EBPβTg/3×Tg-AD+eHSD+H-151 group had significantly increased area under the latency curve, significantly decreased proportion of time spending in the targeted quadrant, and significantly increased p-tau and tau oligomers expressions, Aβ 40 and Aβ 42 concentration in the hippocampus ( P<0.05). Conclusion:The eHSD aggravates cognitive impairment in 3×Tg-AD mice through activating cGAS-STING-C/EBPβ pathway.

BACKGROUND: Several studies have demonstrated the occurrence of secondary tumors as a rare but significant complication of chimeric antigen receptor T (CAR-T) cell therapy, underscoring the need for a detailed investigation. Given the limited variety of secondary tumor types reported to date, a comprehensive characterization of the various secondary tumors arising after CAR-T therapy is essential to understand the associated risks and to define the role of the immune microenvironment in malignant transformation. This study aims to characterize the immune microenvironment of a newly identified secondary tumor post-CAR-T therapy, to clarify its pathogenesis and potential therapeutic targets. METHODS: In this study, the bone marrow (BM) samples were collected by aspiration from the primary and secondary tumors before and after CD19 CAR-T treatment. The CD45 + BM cells were enriched with human CD45 microbeads. The CD45 + cells were then sent for 10× genomics single-cell RNA sequencing (scRNA-seq) to identify cell populations. The Cell Ranger pipeline and CellChat were used for detailed analysis. RESULTS: In this study, a rare type of secondary chronic myelomonocytic leukemia (CMML) were reported in a patient with diffuse large B-cell lymphoma (DLBCL) who had previously received CD19 CAR-T therapy. The scRNA-seq analysis revealed increased inflammatory cytokines, chemokines, and an immunosuppressive state of monocytes/macrophages, which may impair cytotoxic activity in both T and natural killer (NK) cells in secondary CMML before treatment. In contrast, their cytotoxicity was restored in secondary CMML after treatment. CONCLUSIONS This finding delineates a previously unrecognized type of secondary tumor, CMML, after CAR-T therapy and provide a framework for defining the immune microenvironment of secondary tumor occurrence after CAR-T therapy. In addition, the results provide a rationale for targeting macrophages to improve treatment strategies for CMML treatment.
Humans ; Lymphoma, Large B-Cell, Diffuse/therapy* ; Tumor Microenvironment/genetics* ; Antigens, CD19/metabolism* ; Leukemia, Myelomonocytic, Chronic/genetics* ; Immunotherapy, Adoptive/adverse effects* ; Male ; Single-Cell Analysis/methods* ; Female ; Sequence Analysis, RNA/methods* ; Receptors, Chimeric Antigen ; Middle Aged

Objective:To investigate the effect of early high-sucrose diet (eHSD) on cognitive function and its regulatory mechanism in 3×Tg-AD mice.Methods:(1) Eighteen specific-pathogen-free (SPF)-grade 2-month-old wide-type (WT) mice were randomly divided into a WT+normal chow diet (NCD) group and a WT+eHSD group, with 9 mice in each group; and 18 SPF-grade 2-month-old 3×Tg-AD mice were randomly divided into a 3×Tg-AD+NCD group and a 3×Tg-AD+eHSD group, with 9 mice in each group. At 2-5 months old, mice in the 4 groups received standard laboratory food+purified water or 30% sucrose water, followed by standard feed for all groups. At 8 months old, cognitive function was assessed by Morris water maze test; fluorescent intensity of AT8 (phosphorylated [p]-tau) and T22 (tau oligomers) in the hippocampal tissues was detected by immunofluorescent staining; concentrations of β-amyloid protein (Aβ) 42 and Aβ 40 were detected by enzyme-linked immunosorbent assay (ELISA); protein expressions of stimulator of interferon genes (STING), TANK-binding kinase 1 (TBK1), p-TBK1, and CCAAT/enhancer-binding protein β (C/EBPβ) were detected by Western blotting; activity of C/EBPβ transcription factor was detected by activity assay; mitochondrial DNA (mtDNA) content in the cytoplasm of cell was detected by real-time quantitative PCR (qPCR). (2) Eighteen SPF-grade 2-month-old 3×Tg-AD mice were randomized into a 3×Tg-AD+eHSD+H-151 group and a 3×Tg-AD+eHSD+dimethyl sulfoxide (DMSO) group, with 9 mice in each group. Mice at 2-5 months old were given standard laboratory food+30% sucrose water; they were, respectively, injected intraperitoneally with STING pathway inhibitor H-151 or DMSO at 5 months old, and continually injected until 8 months old; and then, the behavioral testing, immunofluorescent staining, ELISA, Western blotting and C/EBPβ transcription factor activity experiments were repeated as before. (3) After crossing C/EBPβ heterozygous knockout (C/EBPβ +/-) mice with 3×Tg-AD mice, 3×Tg-AD/C/EBPβ +/- mice were obtained, and 3×Tg-AD mice were used as controls; they were named 3×Tg-AD/C/EBPβ +/-+eHSD group and 3×Tg-AD+eHSD group, with 9 mice in each group. Both groups of mice were given standard laboratory food+30% sucrose water at 2-5 months old, followed by standard feed until 8 months old; and then, the behavioral testing, immunofluorescent staining, ELISA, and Western blotting experiments were repeated as before. (4) C/EBPβ transgenic mice (C/EBPβTg) were crossed with 3×Tg-AD mice to obtain C/EBPβTg/3×Tg-AD mice, and Non-Tg/3×Tg-AD mice were used as controls; they were, respectively, named as C/EBPβTg/3×Tg-AD+eHSD+H-151 group, Non-Tg/3×Tg-AD+eHSD+H-151 group, and Non-Tg/3×Tg-AD+eHSD+DMSO group, with 9 mice in each group. All 3 groups of mice were given standard laboratory food+30% sucrose water at 2-5 months old; at 5-8 months old, mice in the C/EBPβTg/3×Tg-AD+eHSD+H-151 group and Non-Tg/3×Tg-AD+eHSD+H-151 group were intraperitoneally injected with H-151, while mice in the Non-Tg/3×Tg-AD+eHSD+DMSO group were injected with DMSO; and then, the behavioral testing, immunofluorescent staining, ELISA, and Western blotting experiments were repeated as before. Results:(1) Compared with those in the WT+NCD group and WT+eHSD group, area under the latency curve of 3×Tg-AD+eHSD mice was significantly increased, and proportion of time spending in the targeted quadrant of mice in the 3×Tg-AD+NCD group and 3×Tg-AD+eHSD group was significantly decreased ( P<0.05); compared with that in the 3×Tg-AD+NCD group, proportion of time spending in the targeted quadrant in mice of the 3×Tg-AD+eHSD group was significantly reduced ( P<0.05). Compared with the 3×Tg-AD+NCD group, the 3×Tg-AD+eHSD group had significantly increased p-tau and tau oligomers, Aβ 42 and Aβ 40 concentrations in the hippocampus (AT8 fluorescent intensity: 1.000±0.076 vs. 2.902±0.399; T22 fluorescent intensity: 1.000±0.145 vs. 2.495±0.273; Aβ 42: 1.000±0.167 vs.1.956±0.132; Aβ 40: 1.000±0.226 vs.1.900±0.116), significantly increased C/EBPβ protein expression and C/EBPβ transcription factor activity (1.000±0.164 vs. 1.804±0.112; 1.000±0.216 vs. 2.743±0.301), and statistically increased mtDNA level detected by D-loop1 and D-loop3 (1.000±0.234 vs. 2.800±0.210; 1.000±0.155 vs. 2.952±0.078; P<0.05). Compared with the 3×Tg-AD+NCD group, the 3×Tg-AD+eHSD group had significantly increased STING protein expression and p-TBK1/TBK1 ratio (STING: 1.000±0.192 vs. 2.093±0.081; p-TBK1/TBK1: 1.000±0.148 vs. 1.561±0.112, P<0.05). (2) Compared with the 3×Tg-AD+eHSD+DMSO group, the 3×Tg-AD+eHSD+H-151 group had significantly decreased area under the latency curve, significantly increased proportion of time spending in the targeted quadrant, significantly decreased p-tau and tau oligomers expressions, Aβ 42 and Aβ 40 concentrations in the hippocampus (AT8 fluorescent intensity: 1.000±0.142 vs. 0.538±0.057; T22 fluorescent intensity: 1.000±0.104 vs. 0.665±0.088; Aβ 42: 1.000±0.084 vs. 0.600±0.007; Aβ 40: 1.000±0.138 vs. 0.476±0.083), significantly decreased STING protein expression and p-TBK1/TBK1 ratio (STING: 1.000±0.054 vs. 0.468±0.111; p-TBK1/TBK1: 1.000±0.057 vs. 0.598±0.090), and significantly decreased C/EBPβ transcription factor activity (1.000±0.097 vs. 0.445±0.106; P<0.05). (3) Compared with the 3×Tg-AD+eHSD group, the 3×Tg-AD/C/EBPβ +/-+eHSD group had significantly decreased area under the latency curve, significantly increased proportion of time spending in the targeted quadrant, significantly decreased p-tau and tau oligomers, Aβ 42 and Aβ 40 concentrations in the hippocampus (AT8 fluorescent intensity: 1.000±0.160 vs. 0.506±0.065; T22 fluorescent intensity: 1.000±0.127 vs. 0.346±0.048; Aβ 42: 1.000±0.017 vs. 0.510±0.101; Aβ 40: 1.000±0.098 vs. 0.586±0.153), and significantly decreased C/EBPβ protein expression (1.000±0.101 vs. 0.568±0.094; P<0.05). (4) Compared with the Non-Tg/3×Tg-AD+eHSD+DMSO group, the Non-Tg/3×Tg-AD+eHSD+H-151 group had significantly decreased area under the latency curve, significantly increased proportion of time spending in the targeted quadrant, and significantly decreased p-tau and tau oligomers expressions, Aβ 40 concentration in the hippocampus, and the Non-Tg/3×Tg-AD+eHSD+H-151 group, the C/EBPβTg/3×Tg-AD+eHSD+H-151 group had significantly decreased STING protein expression and p-TBK1/TBK1 ratio in the hippocampus ( P<0.05). Compared with the Non-Tg/3×Tg-AD+eHSD+H-151 group, the C/EBPβTg/3×Tg-AD+eHSD+H-151 group had significantly increased area under the latency curve, significantly decreased proportion of time spending in the targeted quadrant, and significantly increased p-tau and tau oligomers expressions, Aβ 40 and Aβ 42 concentration in the hippocampus ( P<0.05). Conclusion:The eHSD aggravates cognitive impairment in 3×Tg-AD mice through activating cGAS-STING-C/EBPβ pathway.

OBJECTIVE To investigate the in vitro inhibitory mechanism of berberine on the proliferation of tumor stem cells and evaluate its in vivo safety. METHODS Flow cytometry was used to select tumor stem cells from mouse skin melanoma B16F10 cells； CD44， CD133， Nanog homologous box protein （NANOG） and octamer-binding transcription factor 4 （OCT4） were used as indicators to characterize tumor stem cells. Tumor stem cells were divided into control group， all-trans retinoic acid （ATRA） group， and berberine group， and the CCK-8 method was used to detect the effects of berberine on the viability of tumor stem cells； flow cytometry was adopted to detect cell apoptotic rate， the proportion of CD44+/CD133+ and the positive cell rate of sex determining region Y box protein 2 （SOX2）； the morphological changes of tumor balls were recorded after treatment with berberine； the morphology of cell pyroptosis in each group was recorded， and the release rate of lactate dehydrogenase （LDH） was detected； Western blot assay was adopted to detect the expressions of pyroptosis-related protein gasdermin E （GSDME）， GSDME- N， caspase-3 and cleaved caspase-3. Preliminary evaluation of in vivo safety of berberine was conducted by using zebrafish embryo toxicity experiments. RESULTS Compared with B16F10 cells， the proportion of CD44+/CD133+ cells in tumor stem cells and the fluorescence intensity of NANOG and OCT4 were significantly increased （P＜0.000 1）. The half-inhibitory concentration of berberine to tumor stem cells was 50.98 μmol/L. Compared with the control group， the apoptotic rate of cells in the berberine group was significantly increased， while the proportion of CD44+/CD133+ cells and the rate of SOX2 positive cells were reduced significantly （P＜0.000 1）； tumor stem cell spheroids were atrophied， with partial cell death. After treatment with berberine， tumor stem cells exhibited swelling in their outermost layer， the release rate of LDH of cells was significantly increased and the release rate of LDH increased with increasing dose； the protein expressions of GSDME-N and cleaved-caspase-3 of cells in berberine 20， 40 μmol/L groups were significantly increased， and the protein expressions of GSDME and caspase-3 were significantly reduced （except for berberine 20 μmol/L group， P＜0.05）. The embryonic development of zebrafish treated with berberine was almost unaffected， and the survival rate of embryo reached 100%， with no obvious abnormalities observed. CONCLUSIONS Berberine has good activity against the proliferation of tumor stem cells， and its mechanism of action may be related to activating GSDME and promoting cell pyroptosis； berberine has good in vivo safety.

BACKGROUND: Glutamine synthetase (GS) and arginase 1 (Arg1) are widely used pathological markers that discriminate hepatocellular carcinoma (HCC) from intrahepatic cholangiocarcinoma; however, their clinical significance in HCC remains unclear. METHODS: We retrospectively analyzed 431 HCC patients: 251 received hepatectomy alone, and the other 180 received sorafenib as adjuvant treatment after hepatectomy. Expression of GS and Arg1 in tumor specimens was evaluated using immunostaining. mRNA sequencing and immunostaining to detect progenitor markers (cytokeratin 19 [CK19] and epithelial cell adhesion molecule [EpCAM]) and mutant TP53 were also conducted. RESULTS: Up to 72.4% (312/431) of HCC tumors were GS positive (GS+). Of the patients receiving hepatectomy alone, GS negative (GS-) patients had significantly better overall survival (OS) and recurrence-free survival (RFS) than GS+ patients; negative expression of Arg1, which is exclusively expressed in GS- hepatocytes in the healthy liver, had a negative effect on prognosis. Of the patients with a high risk of recurrence who received additional sorafenib treatment, GS- patients tended to have better RFS than GS+ patients, regardless of the expression status of Arg1. GS+ HCC tumors exhibit many features of the established proliferation molecular stratification subtype, including poor differentiation, high alpha-fetoprotein levels, increased progenitor tumor cells, TP53 mutation, and upregulation of multiple tumor-related signaling pathways. CONCLUSIONS GS- HCC patients have a better prognosis and are more likely to benefit from sorafenib treatment after hepatectomy. Immunostaining of GS may provide a simple and applicable approach for HCC molecular stratification to predict prognosis and guide targeted therapy.
Humans ; Carcinoma, Hepatocellular/metabolism* ; Sorafenib/therapeutic use* ; Liver Neoplasms/metabolism* ; Glutamate-Ammonia Ligase/metabolism* ; Hepatectomy ; Retrospective Studies ; Prognosis ; Neoplasm Recurrence, Local/surgery*

RNAs are involved in the crucial processes of disease progression and have emerged as powerful therapeutic targets and diagnostic biomarkers. However, efficient delivery of therapeutic RNA to the targeted location and precise detection of RNA markers remains challenging. Recently, more and more attention has been paid to applying nucleic acid nanoassemblies in diagnosing and treating. Due to the flexibility and deformability of nucleic acids, the nanoassemblies could be fabricated with different shapes and structures. With hybridization, nucleic acid nanoassemblies, including DNA and RNA nanostructures, can be applied to enhance RNA therapeutics and diagnosis. This review briefly introduces the construction and properties of different nucleic acid nanoassemblies and their applications for RNA therapy and diagnosis and makes further prospects for their development.

Objective To investigate the value of optical trocar insertion technique in establishing pneumoperitoneum in patients undergoing laparoscopic surgery after previous abdominal surgery. Methods A total of 29 patients, with a history of abdominal surgery, who planned to undergo laparoscopic liver surgery were enrolled and randomly divided into optical trocar insertion group and open approach group. The independent samples t -test was used for comparison of normally distributed continuous data between groups, and the Mann-Whitney U test was used for comparison of non-normally distributed continuous data between groups; the Fisher's exact test was used for comparison of categorical data between groups; the Mann-Whitney U test was used for comparison of ranked data between groups. Results There were no procedure-related complications in either group. Compared with the open approach group, the optical trocar insertion group had a significantly shorter time required to establish pneumoperitoneum [35.00 (21.00-46.00) seconds vs 180.00 (152.50-252.50) seconds, U =0, P < 0.001] and a significantly smaller incision length [1.10(1.00-1.20) cm vs 2.80(2.45-3.00) cm, U =0, P < 0.001]. Conclusion Both optical trocar insertion and open approach for establishing pneumoperitoneum is relatively safe in patients undergoing laparoscopic liver surgery after previous abdominal surgery, while optical trocar insertion has the advantages of high efficiency and minimal invasiveness in establishing pneumoperitoneum.

Objective To investigate the effects of protocadherin 20 (PCDH20) in the spinal cord in the development of bone cancer pain (BCP) in rats.Methods Thirty-six SPF female Sprague-Dawley rats,weighing 180-200 g,were randomly divided into 4 groups (n =9 each):sham operation group (group S),BCP group,lentivirus control group (group LC) and PCDH20 siRNA lentivirus group (group P).Control lentivirus and lentivirus containing PCDH20 siRNA 4 μl were injected into the ipsilateral spinal cord in groups LC and P,respectively.One week later,BCP was induced by injection of Walker 256 breast cancer cells into the upper segment of bone marrow of right tibia.The mechanical paw withdrawal threshold (MWT) was measured at 1 day before injection of lentivirus (T1),1 day before BCP (T2),and 7,14 and 21 days after BCP (T3-5).Three rats in each group were sacrificed after measurement of the MWT at 21 day after BCP and the tibia on the operated side was obtained for examination of invasion of the cancer cells with light microscope.The spinal cord was removed for determination of the expression of PCDH20 and postsynaptic density 95 (PSD95) protein (by Western blot) and mRNA (by RTPCR).Results In groups BCP,LC and P,the cancer cells grew out of the bone and destroyed the cortical bone seriously.Compared with group S,the MWT was significantly decreased at T3-5 in groups BCP,LC and P,the expression of PCDH20 and PSD95 protein and mRNA was up-regulated in groups BCP and LC,and the expression of PCDH20 was up-regulated in group P (P ＜ 0.05).Compared with BCP group,no significant change was found in the MWT and expression of PCDH20 and PSD95 protein and mRNA in group LC (P ＞ 0.05),and the MWT was significantly increased at T4,5 and the expression of PCDH20 and PSD95 protein and mRNA was down-regulated in group P (P ＜ 0.05).Conclusion PCDH20 is involved in the development of BCP through regulating the expression of PSD95 in the spinal cord and adjusting the function of excitatory synapse in rats.