Tumor cell-intrinsic programmed death-ligand 1 (PD-L1) signals mediate tumor initiation, progression and metastasis, but their effects in ameloblastoma (AM) have not been reported. In this comprehensive study, we observed marked upregulation of PD-L1 in AM tissues and revealed the robust correlation between elevated PD-L1 expression and increased tumor growth and recurrence rates. Notably, we found that PD-L1 overexpression markedly increased self-renewal capacity and promoted tumorigenic processes and invasion in hTERT⁺-AM cells, whereas genetic ablation of PD-L1 exerted opposing inhibitory effects. By performing high-resolution single-cell profiling and thorough immunohistochemical analyses in AM patients, we delineated the intricate cellular landscape and elucidated the mechanisms underlying the aggressive phenotype and unfavorable prognosis of these tumors. Our findings revealed that hTERT⁺-AM cells with upregulated PD-L1 expression exhibit increased proliferative potential and stem-like attributes and undergo partial epithelial‒mesenchymal transition. This phenotypic shift is induced by the activation of the PI3K-AKT-mTOR signaling axis; thus, this study revealed a crucial regulatory mechanism that fuels tumor growth and recurrence. Importantly, targeted inhibition of the PD-L1-PI3K-AKT-mTOR signaling axis significantly suppressed the growth of AM patient-derived tumor organoids, highlighting the potential of PD-L1 blockade as a promising therapeutic approach for AM.
Ameloblastoma/metabolism* ; Humans ; B7-H1 Antigen/metabolism* ; Neoplasm Recurrence, Local/pathology* ; Signal Transduction ; Cell Proliferation ; Up-Regulation ; TOR Serine-Threonine Kinases/metabolism* ; Proto-Oncogene Proteins c-akt/metabolism* ; Telomerase/metabolism* ; Jaw Neoplasms/metabolism* ; Epithelial-Mesenchymal Transition ; Animals ; Cell Line, Tumor ; Female ; Male

OBJECTIVETo construct the eukaryotic expression vector of TIMP-2 gene and to explore its expression in human ameloblastoma cell in vitro.

METHODSThe aimed gene fragment was obtained by RT-PCR. And then, molecmicrolar cloning technology and enzyme digestion were used to connect the gene with the plasmid PcDNA3.1(+), which can be expressed in eukaryotic cells and a report gene: green fluorescent protein gene (GFP) was already existed in the plasmid. We named the eukaryotic expression vector, which contended our aimed gene TIMP-2 as well as report gene GFP, PcDNA3.1(+)/GFP-TIMP-2. The vector was identified by PCR analysis, EcoR I and Xho I restriction analysis and Sequence analysis. After the PcDNA3.1(+)/GFP-TIMP-2 was transfected into cultured human ameloblastoma cell, RT-PCR and Flow Cytometry (FCM) and Microscope wre respectively performed to evaluate the effect of transfection and expression.

RESULTSThe constructed vector PcDNA3.1(+)/GFP-TIMP-2 was proved correct by enzyme digestion and sequencing analysis. After PcDNA3.1(+)/GFP-TIMP-2 was trasnfected into cultured human ameloblastoma cell, the rate of transfection is 47.6% (Analysis report of FCM), the green fluorescence was found in plasm (observed with fluo-microwave), the expression of TIMP-2 mRNA was elevated 2.4 times compared with the control group.

CONCLUSIONSPcDNA3.1(+)/GFP-TIMP-2 was successfully constructed and it could be transfected into cultured human ameloblastoma cell. It may be benefit to further study of the relationship between the TIMP-2 gene and the behaviour of ameloblastoma.

Ameloblastoma ; genetics ; metabolism ; Genetic Vectors ; Green Fluorescent Proteins ; genetics ; metabolism ; Humans ; Jaw Neoplasms ; genetics ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Tissue Inhibitor of Metalloproteinase-2 ; genetics ; metabolism ; Transfection ; Tumor Cells, Cultured

OBJECTIVETo detect the expression of macrophage inflammatory protein-1alpha (MIP-1alpha), a disintegrin-like and metalloproteinase (ADAM) 8 and 12 and CD68 protein in giant cell lesions of jaw and giant cell tumors of long bone, and to study their effects on the histogenesis of giant cells in such lesions.

METHODSMIP-1alpha, ADAM8, ADAM12 and CD68 were detected by immunohistochemistry in 24 paraffin-embedded specimens of central giant cell lesions of jaw and giant cell tumors respectively.

RESULTSMIP-1alpha positive signal was located in blood vessels and bone. ADAM8, ADAM12 and CD68 positive signals were located in the cell membrane and cytoplasm of all multinucleated giant cells and some round mononuclear cells in the lesions. In addition, some spindle mononuclear stromal cells were positive for ADAM12 in both lesions.

CONCLUSIONMultinucleated giant cells probably originate from CD68-postive round mononuclear cells, which are recruited from monocyte-macrophage system by chemokines, such as MIP-1alpha, followed by cell fusion mediated by ADAM8 and ADAM12.

ADAM Proteins ; metabolism ; ADAM12 Protein ; Antigens, CD ; metabolism ; Antigens, Differentiation, Myelomonocytic ; metabolism ; Bone Neoplasms ; metabolism ; pathology ; Cell Membrane ; metabolism ; Chemokine CCL3 ; Chemokine CCL4 ; Cytoplasm ; metabolism ; Giant Cell Tumor of Bone ; metabolism ; pathology ; Giant Cells ; metabolism ; Granuloma, Giant Cell ; metabolism ; pathology ; Humans ; Jaw Diseases ; metabolism ; pathology ; Macrophage Inflammatory Proteins ; metabolism ; Membrane Proteins ; metabolism

OBJECTIVETo investigate the expression of cyclin E mRNA, p21(WAF1) mRNA and p27(KIP1) protein in human ameloblastoma (AB), and to explore the clinical and biological characteristics of AB.

METHODSThe expression of cyclin E mRNA, p21(WAF1) mRNA and p27(KIP1) protein in 54 cases of human AB were detected by in situ hybridization or immunohistochemistry (SP method).

RESULTSThe positive expression rate of cyclin E mRNA in the cytoplasm or cell nucleus of AB was 66.7% (36/54). The expression of cyclin E mRNA increased with AB recurrence and malignant transformation, and the difference of expression among primary AB, recurrent AB, and malignant AB, was statistically significant. The positive expression ratio of cyclin E mRNA in OKC was 50.0% (8/16). The p21(WAF1) mRNA expression in the cytoplasm or cell nucleus of AB decreased, and the positive ratio was 22.6% (12/54) in AB, 37.5% (6/16) in OKC, respectively. The p27(KIP1) protein expression in the cell nucleus of AB was positive in a small number of cases, and the positive rate was 16.7% (9/54) in AB, 6.3% (1/16) in OKC, respectively.

CONCLUSIONSThe genesis and invasion of AB is associated with the cell proliferation and differentiation, and regulated by the higher expression of cyclin E and the lower expression of p21(WAF1) and p27(KIP1).

Adolescent ; Adult ; Aged ; Ameloblastoma ; metabolism ; pathology ; Child ; Cyclin E ; genetics ; metabolism ; Cyclin-Dependent Kinase Inhibitor p21 ; genetics ; metabolism ; Cyclin-Dependent Kinase Inhibitor p27 ; Female ; Humans ; Intracellular Signaling Peptides and Proteins ; genetics ; metabolism ; Jaw Neoplasms ; metabolism ; pathology ; Middle Aged ; Oncogene Proteins ; genetics ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Young Adult

OBJECTIVETo investigate the expression of pRb and E2F-1, and the association between their expression and the activity of telomerase (hTERT) or cyclin E in human ameloblastoma (AB), and to explore the clinical biological characteristics of AB.

METHODSThe expressions of pRb, E2F-1, cyclin E and hTERT mRNA in human AB were detected by in situ hybridization or immunohistochemistry (SP method).

RESULTSThe positive expression ratio of pRb in the cell nucleus of AB was 20.4% (11/54). The positive ratio of E2F-1, cyclin E and hTERT mRNA was 92.6% (50/54), 66.7% (36/54) and 94.4% (51/54), respectively. With AB recurrence and malignant transformation, the expression of hTERT, E2F-1, cyclin E was up-regulated. hTERT and cyclin E or E2F-1 mRNA had high positive relation (Spearsman'r(s) = 1.000, P = 0.0001).

CONCLUSIONSThe regulatory pathway of Rb/E2F-1 is associated with the cell proliferation and in differentiation of AB. The activity or release of telomerase may be related to the lower expression of Rb and higher expression of E2F-1, and is up-regulated in G(1) late phase by cyclin E.

Adolescent ; Adult ; Aged ; Ameloblastoma ; metabolism ; pathology ; Child ; Cyclin E ; biosynthesis ; E2F1 Transcription Factor ; biosynthesis ; Female ; Humans ; Jaw Neoplasms ; metabolism ; pathology ; Male ; Middle Aged ; RNA, Messenger ; biosynthesis ; Retinoblastoma Protein ; biosynthesis ; Telomerase ; genetics ; metabolism

OBJECTIVETo detect the expression of a disintegrin-like and metalloproteinase (ADAM) 8 and 12 gene in the giant cell lesions of jaw and to study their effects on the histogenesis of cells in these lesions.

METHODSADAM8 and ADAM12 was detected by immunohistochemistry (SP) in 40 paraffin-embedded specimens of central giant cell lesions of jaw, 10 peripheral giant cell lesions, 9 cherubisms, 6 aneurysmal bone cysts.

RESULTSADAM8 and ADAM12 were positive in the cytomembrane and cytoplasm of all multinucleated giant cells and some round mononuclear cells of the lesions; ADAM12 was positive for some spindle mononuclear stromal cells in central and peripheral giant cell lesions.

CONCLUSIONSMultinucleated giant cells probably originated from the fusion of the round mononuclear cells, and ADAM8 and ADAM12 were involved in this process. In addition, ADAM12 might play a role in the maturation of spindle mononuclear stromal cells.

ADAM Proteins ; ADAM12 Protein ; Antigens, CD ; biosynthesis ; genetics ; metabolism ; Giant Cell Tumor of Bone ; enzymology ; genetics ; Humans ; Jaw Neoplasms ; enzymology ; genetics ; Maxillary Neoplasms ; enzymology ; genetics ; Membrane Proteins ; biosynthesis ; genetics ; metabolism ; Metalloendopeptidases ; biosynthesis ; genetics ; metabolism

OBJECTIVETo study the expression of telomerase reverse transcriptase (hTERT) and bcl-2 in ameloblastoma (AB), METHODS: hTERT mRNA in 54 cases of AB (primary AB 31 cases, recurrent AB 17 cases, malignant AB 4 cases) and 7 cases of oral normal mucosa was detected by in situ hybridization, and bcl-2 by S-P method.

RESULTSThe expression of hTERT mRNA was negative or weak in normal oral mucosa (14.3%), moderate or strong in AB (94.4%). There was a significant difference in these two groups (P < 0.001). The difference between the expressions of hTERT in primary, recurrent and malignant AB was significant (P < 0.05). The positive ratio of bcl-2 in AB and normal oral mucosa was respectively 88.0%, 44.4%. There was a significant statistical difference in these two groups (P < 0.001). hTERT mRNA was stronger in recurred or malignantly transformed AB (P < 0.05).

CONCLUSIONThe expression of hTERT and bcl-2 is stronger in recurred or malignantly transformed AB, and it could be used as an indicator of AB prognosis. Telomerase activity and bcl-2 expression play an important role in genesis and development of AB.

Adolescent ; Adult ; Ameloblastoma ; enzymology ; metabolism ; Biomarkers, Tumor ; Child ; DNA-Binding Proteins ; Female ; Humans ; Jaw Neoplasms ; enzymology ; metabolism ; Male ; Middle Aged ; Neoplasm Recurrence, Local ; enzymology ; metabolism ; Proto-Oncogene Proteins c-bcl-2 ; biosynthesis ; genetics ; RNA, Messenger ; biosynthesis ; genetics ; Telomerase ; biosynthesis ; genetics

OBJECTIVEThe expression of Ki-67 antigen of ameloblastoma was examined in order to investigate the different proliferation activity of histological variants of ameloblastoma and its clinical significance.

METHODS70 cases of different histological specimen of ameloblastoma were analyzed by immunohistochemical method using Ki-67 antibody. The Label Index was calculated in percentage of Ki-67 positive cells after examined with an image analysis system.

RESULTSThe results showed that the Labeled Index in malignant ameloblastoma was the highest 14.72% +/- 2.87%. The Labeled Index in solid ameloblastoma was in the middle, among which the follicular 4.42% +/- 1.05% was higher than the plexiform 3.64% +/- 1.23%. The Labeled Index in mono-cystic ameloblastoma was the lowest 2.21% +/- 1.09%.

CONCLUSIONThe results demonstrated that the proliferation activity varied according to the histological pattern of ameloblastoma. The prognosis with different proliferation activity was also varied accordingly.

Ameloblastoma ; metabolism ; pathology ; Humans ; Image Processing, Computer-Assisted ; Jaw Neoplasms ; metabolism ; pathology ; Ki-67 Antigen ; biosynthesis ; Neoplasm Recurrence, Local ; Odontogenic Tumors ; metabolism ; pathology

OBJECTIVETo study relation of the expression of hTERT mRNA and cyclin A, p53 protein, proliferation cell nuclear antigen (PCNA) in ameloblastoma (AB) and to investigate clinical biological characteristics of AB.

METHODSThe hTERT mRNA was detected by in situ hybridization, cyclin A, p53 protein and PCNA by SP method. Normal oral mucosa and odontogenic keratocyst (OKC) are comparition.

RESULTSThe positive ratio of hTERT mRNA was 1/7 cases in normal oral mucosa. The expression of cyclin A, p53 and PCNA in normal oral mucosa were similar, and the positive cells distributed in stratum basale. In OKC, the positive cells distributed in stratum basale and super-strrtum basale. And the positive ratio of hTERT, cyclin A, p53, PCNA in OKC was 14/16 cases, 4/32 cases, 11/25 cases, 5/9 cases, respectively. In AB, the positive ratio of hTERT mRNA, cyclin A, p53 protein and PCNA was 94.4% (51/54), 66.7% (40/60), 85.7% (42/49) and 78.1% (25/32), respectively. A strong correlation was found between hTERT mRNA with cyclin A, p53 protein and PCNA (r(s) = 0.914, 0.848, 0.804, P < 0.05).

CONCLUSIONSThe expression of hTETR mRNA, cyclin A, p53 and PCNA is different in different tissues and lesions, and correlates with cell differentiation and clinical biology behaviour. Telomerase activity is related to cumulation of p53 protein, related to cell proliferation and differentiation, regulated by cyclin A, and higher in S phase.

Ameloblastoma ; metabolism ; pathology ; Cyclin A ; biosynthesis ; Humans ; Jaw Neoplasms ; metabolism ; pathology ; Proliferating Cell Nuclear Antigen ; biosynthesis ; RNA, Messenger ; biosynthesis ; Telomerase ; biosynthesis ; genetics ; Tumor Suppressor Protein p53 ; biosynthesis

OBJECTIVETo investigate the proliferative potential of the epithelial cells in odontogenic keratocyst, radicular cyst, dentigerous cyst and ameloblastoma.

METHODSDNA contents and ploidy of basal and spinous cells in keratocyst, radicular cyst, dentigerous cyst, and the peripheral column cells and central reticular cells in ameloblastoma were analysis respectively.

RESULTSThe more and higher DNA contents and the proliferating ploidy of keratocyst and ameloblastoma than those of radicular cyst and dentigerous cyst indicate the active proliferating potential. The spinous cells showed more active proliferating growth than the basal cells of keratocyst. The higher DNA contents of radicular cyst are related to the stimulus of the inflammation. The dentigerous cysts have more di-ploidy cells without active growth potential.

CONCLUSIONSThe active cell proliferating growth in keratocyst and ameloblastoma is probably the pathological basis of their local aggressive biological behavior.

Ameloblastoma ; genetics ; pathology ; Cell Division ; genetics ; DNA ; metabolism ; Humans ; Jaw Neoplasms ; genetics ; pathology ; Odontogenic Cysts ; genetics ; pathology ; Ploidies