Objective To investigate the value of ultrasonographic features combined with immunohistochemistry in predicting axillary lymph node metastasis in middle-aged women with breast cancer.Methods A retrospective analysis was conducted on 827 middle-aged female breast cancer patients who underwent surgical treatment at the Affiliated Hospital of Chengde Medical University from June 2017 to June 2023.Ultrasonographic and immunohistochemical information was collected,and the patients were randomly allocated into a training set(579 patients)and a validation set(248 patients).Univariate and multivariate Logistic regression analyses were performed to identify ultrasonographic and immunohistochemical risk factors associated with axillary lymph node metastasis in these patients,and a nomogram model was developed.Receiver operating characteristic curves and calibration curves were established to evaluate the performance of the nomogram model,and clinical decision curves were built to assess the clinical value of the model.Results The maximum diameter,morphology,boundary,calcification,and expression of human epidermal growth facor receptor 2 and Ki-67 in breast cancer lesions were identified as risk factors for predicting axillary lymph node metastasis in middle-aged women.The areas under the curve of the nomogram model on the training and validation sets were 0.747(0.707-0.787)and 0.714(0.647-0.780),respectively.Calibration curves and clinical decision curves indicated good consistency and performance of the model.Conclusion The nomogram model constructed based on ultrasonographic features and immunohistochemistry of the primary breast cancer lesion demonstrates high value in predicting axillary lymph node metastasis in middle-aged women with breast cancer.
Humans ; Female ; Breast Neoplasms/diagnostic imaging* ; Middle Aged ; Lymphatic Metastasis/diagnostic imaging* ; Axilla ; Retrospective Studies ; Nomograms ; Ultrasonography ; Immunohistochemistry ; Lymph Nodes/diagnostic imaging* ; Risk Factors ; Ki-67 Antigen

OBJECTIVES: To explore the clinical significance of the tertiary lymphoid structure (TLS) maturity in colorectal cancer patients. METHODS: A total of 230 surgically removed colorectal cancer specimens with detailed follow-up data were collected from Yinzhou Second Hospital. The patients were divided into mature TLS group and immature TLS group according to immunohistochemical results. The patient age, gender, maximum tumor diameter, tumor location, differentiation degree, depth of invasion, lymph node metastasis, vascular tumor thrombus, liver metastasis, distant non-liver metastasis, mismatch repair status, expression of Ki-67, P53 and programmed death-ligand (PD-L) 1 were analyzed. The Kaplan-Meier method (Breslow test) was used to analyze the survival of patients, and multivariate Cox regression model was applied to analyze the prognostic factors. RESULTS: There were 128 cases of mature TLS and 102 cases of immature TLS. Compared to the immature TLS group, the mature TLS group showed a significantly lower rate of vascular tumor thrombus, lymph node metastasis, and liver metastasis. Additionally, the positive expression rate of Ki-67 was markedly reduced, while the rate of deficient mismatch repair and the positive rate of PD-L1 were significantly increased (all P<0.05). The overall survival rate of the mature TLS group was superior to that of the immature TLS group (Breslow=4.553, P<0.05). Cox regression analysis indicated that lymph node metastasis was an independent risk factor for the prognosis of colorectal cancer patients (P<0.01), while TLS maturation was a protective factor (P<0.05). CONCLUSIONS The formation of TLS may play a significant role in inhibiting lymph node metastasis, liver metastasis, and vascular tumor thrombus in colorectal cancer. In addition, patients with mature TLS have a favorable clinical prognosis.
Humans ; Colorectal Neoplasms/pathology* ; Male ; Female ; Middle Aged ; Tertiary Lymphoid Structures/pathology* ; Prognosis ; Aged ; Adult ; Lymphatic Metastasis ; Ki-67 Antigen/metabolism* ; B7-H1 Antigen/metabolism* ; Clinical Relevance

OBJECTIVES: Clear cell renal cell carcinoma (ccRCC) is the most common subtype of renal cell carcinoma (RCC), and developing personalized treatment strategies is crucial for improving patient prognosis. This study aims to develop and validate a preoperative computer tomography (CT) radiomics-based predictive model to estimate Ki-67 expression in ccRCC patients, thereby assisting in clinical treatment decisions and prognosis prediction. METHODS: A retrospective analysis was conducted on 214 ccRCC patients who underwent surgical treatment at Gansu Provincial Hospital between January 2018 and November 2023. Patients were classified into high Ki-67 expression (n=123) and low Ki-67 expression (n=91) groups based on postoperative immunohistochemical staining results. The dataset was randomly divided in a 7꞉3 ratio into a training set (n=149) and a validation set (n=65). Preoperative contrast-enhanced urinary CT images and clinical data were collected. After preprocessing, 5 mm arterial-phase CT images were manually segmented layer by layer to delineate the region of interest (ROI) using ITK-SNAP 3.8 software. Radiomic features were then extracted using the FeAture Explorer (FAE) package. Dimensionality reduction and feature selection were performed using the least absolute shrinkage and selection operator (LASSO) algorithm, yielding the optimal feature set. Three classification models were constructed using logistic regression (LR), multilayer perceptron (MLP), and support vector machine (SVM). The receiver operating characteristic (ROC) curve, area under the curve (AUC), decision curve analysis (DCA), and calibration curves were used for model evaluation. RESULTS: A total of 107 radiomic features were extracted from 5 mm arterial-phase CT images, and twenty-one features significantly associated with Ki-67 expression were selected using the LASSO algorithm. Predictive models were developed using LR, MLP, and SVM classifiers. In the training and validation sets, the AUC values for each model were 0.904 (95% CI 0.852 to 0.956) and 0.818 (95% CI 0.710 to 0.926) for the LR model, 0.859 (95% CI 0.794 to 0.923) and 0.823 (95% CI 0.716 to 0.929) for the MLP model, and 0.917 (95% CI 0.865 to 0.969) and 0.857 (95% CI 0.760 to 0.953) for the SVM model. DCA demonstrated that all models had good clinical net benefit, while calibration curves indicated high accuracy of the predictions, supporting the robustness and reliability of the models. CONCLUSIONS A CT radiomics-based model for predicting Ki-67 expression in ccRCC was successfully developed. This model provides valuable guidance for treatment planning and prognostic assessment in ccRCC patients.
Humans ; Carcinoma, Renal Cell/surgery* ; Kidney Neoplasms/surgery* ; Tomography, X-Ray Computed/methods* ; Ki-67 Antigen/metabolism* ; Retrospective Studies ; Female ; Male ; Middle Aged ; Aged ; Prognosis ; Adult ; Preoperative Period ; Radiomics

OBJECTIVES: Shear wave elastography (SWE) is a novel quantitative elastography technique that can assess the hardness of different tissues. This study introduces a novel shear wave parameter-frequency of mass characteristic (f_mass)-and investigates its correlation, along with other shear wave parameters, with the histopathological features and immunohistochemical (IHC) biomarkers of invasive breast cancer (IBC). The study aims to explore whether SWE can provide useful information for IBC treatment and prognosis. METHODS: With the pathological results as the gold standard, 258 malignant breast lesions were collected, and all patients underwent conventional ultrasound and SWE examinations. The SWE parameters [maximum elastic value (E_max), minimum elastic value (E_min), mean elastic value (E_mean), standard deviation of elastic value of the whole lesion (E_sd)] and f_mass] in the transverse and longitudinal orthogonal sections were measured, and their correlations with the prognostic factors of IBC [including tumor diameters, axillary lymph node (ALN) metastasis, lymphatic vessel invasion (LVI), calcification, histological type, histological grade, and IHC biomarkers (ER, PR, HER-2, Ki-67), and molecular subtypes] were analyzed. The correlations between the SWE parameters of the transverse and longitudinal sections of the tumors with different prognostic factors and the above indicators were analyzed. At the same time, the receiver operating characteristic (ROC) curve was used to analyze the efficacy of f_mass in predicting ER and PR expression. RESULTS: E_mean, E_max, E_sd, and f_mass were correlated with tumor diameters; E_mean, E_max and E_sd were correlated with histological types and histological grades. E_max and E_sd were correlated with ALN metastasis, LVI and pathological types. In the IHC biomarker-labeled masses, f_mass was correlated with ER and PR (both P<0.05), and E_mean, E_max, and E_sd were correlated with HER-2 and Ki-67 (all P<0.05). E_mean, E_max, and f_mass were all correlated with breast cancer subtypes (all P<0.05), and E_mean and E_max were higher in Luminal B [HER-2(+)] breast cancer, while f_mass was lower in HER-2(+) and triple-negative breast cancer. Among the statistically significant prognostic factors, the P values of the transverse sections of the masses were all less than or equal to those of the longitudinal sections. The AUC of f_mass in the transverse sections of the masses for predicting ER and PR expression were 0.73 (95% CI 0.65 to 0.80) and 0.67 (95% CI 0.60 to 0.74), respectively, with the optimal cut-off values being 76.50 and 60.66, the sensitivities being 72.45% and 81.98%, the specificities being 66.13% and 45.35%, and the accuracies being 70.93% and 69.77%, respectively. The AUC of f_mass in the longitudinal sections of the masses for predicting ER and PR expression were 0.74 (95% CI 0.67 to 0.81) and 0.65 (95% CI 0.58 to 0.72), respectively, with the optimal cut-off values being 131.8 and 137.5, the sensitivities being 69.90% and 66.28%, the specificities being 72.58% and 60.47%, and the accuracies being 70.54% and 64.34%, respectively. The f_mass in the transverse sections of the masses was more statistically significant. CONCLUSIONS The poor prognosis factors of IBC are related to high E_mean, E_min, E_max, E_sd, and low f_mass. The f_mass can predict the expression of ER and PR, and the transverse cut data are more meaningful. SWE is helpful for predicting the invasiveness of IBC.
Humans ; Breast Neoplasms/metabolism* ; Female ; Elasticity Imaging Techniques/methods* ; Biomarkers, Tumor/metabolism* ; Middle Aged ; Adult ; Prognosis ; Immunohistochemistry ; Neoplasm Invasiveness ; Receptor, ErbB-2/metabolism* ; Aged ; Lymphatic Metastasis ; Receptors, Estrogen/metabolism* ; Receptors, Progesterone/metabolism* ; Ki-67 Antigen/metabolism*

Objective: To investigate the effect of rigosertib (RGS) combined with classic chemotherapy drugs including 5-fluorouracil, oxaliplatin, and irinotecan in colorectal cancer. Methods: Explore the synergy effects of RGS and 5-fluorouracil (5-FU), oxaliplatin (OXA), and irinotecan (IRI) on colorectal cancer by subcutaneously transplanted tumor models of mice. The mice were randomly divided into control group, RGS group, 5-FU group, OXA group, IRI group, 5-FU+ RGS group, OXA+ RGS group and IRI+ RGS group. The synergy effects of RGS and OXA on KRAS mutant colorectal cancer cell lines in vitro was detected by CCK-8. Ki-67 immunohistochemistry and TdT-mediated dUTP nick-end labeling (TUNEL) staining were performed on the mouse tumor tissue sections, and the extracted tumor tissue was analyzed by western blot. The blood samples of mice after chemotherapy and RGS treatment were collected, blood routine and liver and kidney function analysis were conducted, and H&E staining on liver sections was performed to observe the side effects of chemotherapy and RGS. Results: The subcutaneously transplanted tumor models were established successfully in all groups. 55 days after administration, the fold change of tumor size of OXA+ RGS group was 37.019±8.634, which is significantly smaller than 77.571±15.387 of RGS group (P=0.029) and 92.500±13.279 of OXA group (P=0.008). Immunohistochemical staining showed that the Ki-67 index of tumor tissue in control group, OXA group, RGS group and OXA+ RGS group were (100.0±16.8)%, (35.6±11.3)%, (54.5±18.1)% and (15.4±3.9)%, respectively. The Ki-67 index of OXA+ RGS group was significantly lower than that in control group (P=0.014), but there was no significant difference compared to OXA group and RGS group (OXA: P=0.549; RGS: P=0.218). TUNEL fluorescence staining showed that the apoptotic level of OXA+ RGS group was 3.878±0.547, which was significantly higher than 1.515±0.442 of OXA group (P=0.005) and 1.966±0.261 of RGS group (P=0.008). Western blot showed that the expressions of apoptosis related proteins such as cleaved-PARP, cleaved-caspase 3 and cleaved-caspase 8 in the tumor tissues of mice in the OXA+ RGS group were higher than those in control group, OXA group and RGS group. After the mice received RGS combined with chemotherapy drugs, there was no significant effect on liver and kidney function indexes, but the combined use of oxaliplatin and RGS significantly reduced the white blood cells [(0.385±0.215)×10(9)/L vs (5.598±0.605)×10(9)/L, P<0.001] and hemoglobin[(56.000±24.000)g/L vs (153.333±2.231)g/L, P=0.001] of the mice. RGS, chemotherapy combined with RGS and chemotherapy alone did not significantly increase the damage to liver cells. Conclusions: The combination of RGS and oxaliplatin has a stronger anti-tumor effect on KRAS mutant colorectal cancer. RGS single agent will not cause significant bone marrow suppression and hepatorenal injury in mice, but its side effects may increase correspondingly after combined with chemotherapy.
Animals ; Mice ; Antineoplastic Combined Chemotherapy Protocols ; Apoptosis Regulatory Proteins ; Colorectal Neoplasms/genetics* ; Fluorouracil/pharmacology* ; Irinotecan/therapeutic use* ; Ki-67 Antigen ; Oxaliplatin ; Proto-Oncogene Proteins p21(ras)/therapeutic use*

This study aims to investigate the effects of Blaps rynchopetera Fairmaire and/or cyclophosphamide on the proliferation and apoptosis of lung cancer cells and decipher the underlying mechanism. B. rynchopetera and cyclophosphamide-containing serum and blank serum were prepared from SD rats. Cell counting kit-8(CCK-8) assay was employed to examine the proliferation of lung cancer cell lines A549 and Lewis treated with corresponding agents. The Jin's formula method was used to evaluate the combined effect of the two drugs. According to the evaluation results, appropriate drug concentrations and lung cancer cell line were selected for subsequent experiments, which included control, B. rynchopetera, cyclophosphamide, B. rynchopetera + cyclophosphamide, and B. rynchopetera + Wnt/β-catenin pathway agonist lithium chloride(LiCl) groups. Immunocytochemistry was employed to measure the expression of proliferation-related proteins in Lewis cells after drug interventions. Flow cytometry was employed to determine the cell cycle and apoptosis. The expression levels of proliferating cell nuclear antigen(PCNA), cyclinD1, B-cell lymphoma 2(Bcl-2), Bcl-2-assiocated X protein(Bax), Wnt1, and β-catenin were determined by Western blot. The results showed that B. rynchopetera and/or cyclophosphamide significantly inhibited the proliferation of A549 and Lewis cells. Compared with B. rynchopetera alone, the combination increased the inhibition rate on cell proliferation. The combination of B. rynchopetera and cyclophosphamide demonstrated a synergistic effect according to Jin's formula-based evaluation. Compared with the control group, the B. rynchopetera, cyclophosphamide, and B. rynchopetera + cyclophosphamide groups showed increased proportion of Lewis cells in G_0/G_1 phase, increased apoptosis rate, up-regulated expression of Bax, and down-regulated expression of PCNA, cyclinD1, Bcl-2, Wnt1, and β-catenin. Compared with the cyclophosphamide group, the combination group showed increased proportion of cells in G_0/G_1 phase, increased apoptosis rate, up-regulated expression of Bax, and down-regulated expression of PCNA, cyclinD1, Bcl-2, Wnt1, and β-catenin. Compared with the B. rynchopetera group, the B. rynchopetera + LiCl group had deceased proportion of cells in G_0/G_1 phase, decreased apoptosis rate, down-regulated expression of Bax, and up-regulated expression of PCNA, cyclinD1, Bcl-2, Wnt1, and β-catenin. The results indicated that B. rynchopetera could inhibit the proliferation, arrest the cell cycle, and induce the apoptosis of lung cancer cells by inhibiting the Wnt/β-catenin signaling pathway. Moreover, B. rynchopetera had a synergistic effect with cyclophosphamide.
Rats ; Animals ; Wnt Signaling Pathway ; Lung Neoplasms/genetics* ; beta Catenin/metabolism* ; Proliferating Cell Nuclear Antigen ; bcl-2-Associated X Protein/metabolism* ; Rats, Inbred Lew ; Rats, Sprague-Dawley ; Apoptosis ; Proto-Oncogene Proteins c-bcl-2/metabolism* ; Cell Proliferation ; Cyclophosphamide ; Cell Line, Tumor

This study aimed to observe the effect of terpinen-4-ol(T4O) on the proliferation of vascular smooth muscle cells(VSMCs) exposed to high glucose(HG) and reveal the mechanism via the Krüppel-like factor 4(KLF4)/nuclear factor kappaB(NF-κB) signaling pathway. The VSMCs were first incubated with T4O for 2 h and then cultured with HG for 48 h to establish the model of inflammatory injury. The proliferation, cell cycle, and migration rate of VSMCs were examined by MTT method, flow cytometry, and wound healing assay, respectively. The content of inflammatory cytokines including interleukin(IL)-6 and tumor necrosis factor-alpha(TNF-α) in the supernatant of VSMCs was measured by enzyme-linked immunosorbent assay(ELISA). Western blot was employed to determine the protein levels of proliferating cell nuclear antigen(PCNA), Cyclin D1, KLF4, NF-κB p-p65/NF-κB p65, IL-1β, and IL-18. The KLF4 expression in VSMCs was silenced by the siRNA technology, and then the effects of T4O on the cell cycle and protein expression of the HG-induced VSMCs were observed. The results showed that different doses of T4O inhibited the HG-induced proliferation and migration of VSMCs, increased the percentage of cells in G_1 phase, and decreased the percentage of cells in S phase, and down-regulated the protein levels of PCNA and Cyclin D1. In addition, T4O reduced the HG-induced secretion and release of the inflammatory cytokines IL-6 and TNF-α and down-regulated the expression of KLF4, NF-κB p-p65/NF-κB p65, IL-1β, and IL-18. Compared with si-NC+HG, siKLF4+HG increased the percentage of cells in G_1 phase, decreased the percentage of cells in S phase, down-regulated the expression of PCNA, Cyclin D1, and KLF4, and inhibited the activation of NF-κB signaling pathway. Notably, the combination of silencing KLF4 with T4O treatment further promoted the changes in the above indicators. The results indicate that T4O may inhibit the HG-induced proliferation and migration of VSMCs by down-regulating the level of KLF4 and inhibiting the activation of NF-κB signaling pathway.
NF-kappa B/metabolism* ; Interleukin-18/metabolism* ; Proliferating Cell Nuclear Antigen/genetics* ; Cyclin D1/metabolism* ; Tumor Necrosis Factor-alpha/metabolism* ; Muscle, Smooth, Vascular ; Cell Proliferation ; Signal Transduction ; Cytokines/metabolism* ; Glucose/metabolism*

Objective To clarify the effect and mechanism of tumor antigen-loaded dendritic cells (Ag-DCs) combined with cytokine-induced killers (CIKs) on the killing of esophageal cancer tumor cells. Methods Peripheral blood DCs and CIKs were induced and cultured, and the DCs were loaded with tumor antigen to obtain Ag-DCs, and Ag-DCs were co-cultured with CIKs. The experiment was divided into CIK group, DC combined with CIK group, Ag-DC combined with CIK group. Flow cytometry was used to detect the phenotype of cells. MTT assay was employed to determine the killing activity against EC9706 cells. Annexin V-FITC/PI double staining was used to detect the apoptosis rate of cells, immunofluorescence staining to detect the expression of phosphorylated apoptotic signal-regulated kinase 1 (p-ASK1) and Western blot analysis to detect the expression of ASK1 pathway related proteins. A nude mouse model of esophageal cancer transplantation tumor was constructed and divided into control group, DC combined with CIK group and Ag-DC combined with CIK group. The corresponding immune cells were injected into the tail vein for treatment and the tumor volume was measured every 2 days. After 21 days, all nude mice were sacrificed with the tumors taken out. HE staining was used to observe the tumor pathological changes and immunohistochemical staining was performed to detect the expression of ki67 and ASK1 in the tumor tissue. Results Comparedwith the CIK group alone and the DC combined with CIK group, the ratio of CD3⁺ CD8⁺ and CD3⁺ CD56⁺ in the cells significantly increased after Ag-DCs and CIKs co-culture, along with the increased killing rate of EC9706 cells, increased apoptosis rate of EC9706 cells, and the improved activation level of ASK1. Compared with the CIK group and the DC combined with CIK group, the growth of the transplanted tumor in nude mice treated with Ag-DCs combined with CIKs was significantly inhibited, and after 21 days, it was observed that the tumor tissue mass in this group was relatively smaller, with sparsely arranged cells in the tumor tissue and a decline in the positive rate of ki67 in tumor tissue, while the positive rate of ASK1 was significantly increased. Conclusion Co-cultivation of tumor antigen-loaded DCs with CIKs can significantly increase the killing activity of esophageal cancer tumor cells. The mechanism of action may be related to the activation of the ASK1 pathway.
Animals ; Humans ; Mice ; Antigens, Neoplasm ; Cytokine-Induced Killer Cells ; Cytokines/metabolism* ; Cytotoxicity, Immunologic ; Dendritic Cells ; Esophageal Neoplasms/therapy* ; Ki-67 Antigen ; Mice, Nude

OBJECTIVES: To study the effect of platelet-derived growth factor-BB (PDGF-BB) on pulmonary vascular remodeling in neonatal rats with hypoxic pulmonary hypertension (HPH). METHODS: A total of 128 neonatal rats were randomly divided into four groups: PDGF-BB+HPH, HPH, PDGF-BB+normal oxygen, and normal oxygen (n=32 each). The rats in the PDGF-BB+HPH and PDGF-BB+normal oxygen groups were given an injection of 13 μL 6×10¹⁰ PFU/mL adenovirus with PDGF-BB genevia the caudal vein. After 24 hours of adenovirus transfection, the rats in the HPH and PDGF-BB+HPH groups were used to establish a neonatal rat model of HPH. Right ventricular systolic pressure (RVSP) was measured on days 3, 7, 14, and 21 of hypoxia. Hematoxylin-eosin staining was used to observe pulmonary vascular morphological changes under an optical microscope, and vascular remodeling parameters (MA% and MT%) were also measured. Immunohistochemistry was used to measure the expression levels of PDGF-BB and proliferating cell nuclear antigen (PCNA) in lung tissue. RESULTS: The rats in the PDGF-BB+HPH and HPH groups had a significantly higher RVSP than those of the same age in the normal oxygen group at each time point (P<0.05). The rats in the PDGF-BB+HPH group showed vascular remodeling on day 3 of hypoxia, while those in the HPH showed vascular remodeling on day 7 of hypoxia. On day 3 of hypoxia, the PDGF-BB+HPH group had significantly higher MA% and MT% than the HPH, PDGF-BB+normal oxygen, and normal oxygen groups (P<0.05). On days 7, 14, and 21 of hypoxia, the PDGF-BB+HPH and HPH groups had significantly higher MA% and MT% than the PDGF-BB+normal oxygen and normal oxygen groups (P<0.05). The PDGF-BB+HPH and HPH groups had significantly higher expression levels of PDGF-BB and PCNA than the normal oxygen group at all time points (P<0.05). On days 3, 7, and 14 of hypoxia, the PDGF-BB+HPH group had significantly higher expression levels of PDGF-BB and PCNA than the HPH group (P<0.05), while the PDGF-BB+normal oxygen group had significantly higher expression levels of PDGF-BB and PCNA than the normal oxygen group (P<0.05). CONCLUSIONS Exogenous administration of PDGF-BB in neonatal rats with HPH may upregulate the expression of PCNA, promote pulmonary vascular remodeling, and increase pulmonary artery pressure.
Rats ; Animals ; Hypertension, Pulmonary ; Becaplermin ; Animals, Newborn ; Proliferating Cell Nuclear Antigen ; Vascular Remodeling ; Pulmonary Artery/metabolism* ; Hypoxia ; Oxygen ; Cell Proliferation ; Myocytes, Smooth Muscle/metabolism*

Objective: To investigate the effects of nicotine on the morphology, structure of offspring's dental germ, enamel organ and other dental tissues and the further potential epigenetic mechanisms by establishing prenatal nicotine exposure mouse model. Methods: Ten C57BL/6 pregnant mice were randomly divided into control group (physiological saline subcutaneous injection) and prenatal nicotine exposure (PNE) group (nicotine subcutaneous injection) by using a random number table. Postnatal day 0 (P0), postnatal day 14 (P14) and postnatal day 25 (P25) offspring mice were collected for subsequent experiments. The offspring mice were divided into offspring control group and offspring PNE group according to the maternal group respectively. Weights of P0 and P25 offspring mice were recorded. Micro-CT, scanning electron microscope (SEM) and Vickers hardness test were performed to analyze the related parameters of hard tissues including alveolar bones and mandibular incisors. Total RNAs were extracted from mandible tissues and the third generation of dental epithelial stem cells (DESC) in P25 mice. The relative expression levels of osteogenic and ameloblastic differentiation related genes were measured by real-time quantitative PCR (RT-qPCR). Immunohistochemical stainings of paraffin sections were then performed to observe the distribution and expression level of proliferating cell nuclear antigen (Pcna), amelogenin (Amelx), histone H3 trimethylated at lysine 27 (H3K27me3) and enhancer of zeste homolog 2 (Ezh2). Cell counting kit-8 (CCK-8) assays were used to detect the cell viabilities of DESCs after administrations of different concentrations of nicotine (0.01, 0.1, 1 mmol/L) and GSK126 (an inhibitor of histone methyltransferase Ezh2). Results: Compared with the control group, pregnant mice in PNE group were more likely to have adverse pregnancy outcomes, such as significantly lower offspring body weight [P0: offspring control (1.20±0.04) g, offspring PNE (0.99±0.02) g, P<0.001; P25: offspring control (15.26±1.70) g, offspring PNE (9.65±1.32) g, P<0.001] and increased stillbirths rate [offspring control (0), offspring PNE (46.40±9.30) %, P<0.001]. At P14 and P25, the distance parameters between the enamel mineralized deposits of mandibular incisors and the mesial surface of the first molar in offspring PNE group [P14: (-1 349±45) μm; P25: (-1 192±147) μm] was significantly decreased compared with the control group [P14: (-506±380) μm, P25: (504±198) μm] (P<0.05, P<0.001). The enamel column and enamel column stroma of incisors in offspring PNE group were blurred, arranged loosely and disorderly than those in the control group, while the microhardness of incisor enamel in offspring PNE group [(245.7±18.4) MPa] was significantly lower compared to the control group [(371.9±28.7) MPa] (P<0.001). HE staining showed disordered pre-ameloblast (Pre-Am) arrangement and delayed mineralization deposition point in offspring PNE group compared with the control group, while the length of transit-amplifying cell (TA) and Pre-Am region were prolonged as well. Immunohistochemical staining results displayed that the overall Pcna (P<0.05), H3K27me3 (P<0.01), Ezh2 (P<0.01) expression of labial cervical loop (LaCL) in PNE group were increased, while the positive signal of Amelx in ameloblast cytoplasm was impaired. In vitro, the addition of 1 mmol/L nicotine could significantly upregulate the expression level of Pcna (P<0.01) and downregulate the expression levels of B lymphoma Mo-MLV insertion region 1 (P<0.05), leucine rich repeats and immunoglobulin like domains 1 (P<0.05), Amelx (P<0.01). In addition, 1 mmol/L nicotine could also significantly enhance the proliferation activity of DESCs (P<0.001). Addition of 10 μmol/L GSK126, could rescue the proliferation activation effect of 1 mmol/L nicotine on DESCs. Conclusions: PNE may delay the process of enamel formation and lineage differentiation, leading to the abnormal proliferation of DESCs and changes of epigenetic modification state in H3K27me3, which affect the development of enamel in offspring mice,suggesting PNE might be one of risk environmental factor for tooth development.
Pregnancy ; Female ; Mice ; Animals ; Nicotine/toxicity* ; Proliferating Cell Nuclear Antigen ; Histones ; Mice, Inbred C57BL ; Dental Enamel