The interleukin-6/Janus kinase/STAT3 pathway in pleomorphic adenoma and carcinoma ex pleomorphic adenoma of the lacrimal gland

Cell culture in salivary gland tumor research: molecular insights of pathogenic targets and personalized medicine

Salivary gland tumors (SGT) are a diverse group of tumors with various subtypes and morphological characteristics. Cell culture is a low-cost technique used as a valuable tool for studying cancer behavior and molecular characteristics. In vitro studies may offer a controlled environment for initial investigations before conducting in vivo experiments, making them indispensable in cancer research, drug testing, and personalized medicine. SGT cell culture techniques have been utilized to establish cell lines that provide insight into the genetic and molecular alterations underlying these tumors, aiding in the identification of potential therapeutic targets. Here, we highlight the application of cell culture techniques in studying SGT, emphasizing their contribution to advancements in understanding tumor behavior and potential novel therapeutic strategies.

Retrospective Analysis of Clinicopathological Characteristics of Lacrimal Gland Pleomorphic Adenoma and Mechanism of Tumorigenesis by the Imbalance Between Apoptosis and Proliferation

BACKGROUND Lacrimal gland pleomorphic adenoma (LGPA) is the most common clinically benign epithelial tumor of the lacrimal gland and is predominantly comprised of epithelial cells and interstitial components. At present, the exact pathogenesis of LGPA remains unclear. Previous research has indicated that the occurrence of LGPA may be related to excessive cell proliferation. MATERIAL AND METHODS This study observed the clinicopathological characteristics of LGPA and investigated the tumorigenesis mechanism of cell over-proliferation caused by the imbalance between apoptosis and proliferation. A total of 27 cases were collected from the Department of Ophthalmology of the Affiliated Hospital of Chengde Medical University and the Third Medical Center of Chinese PLA General Hospital from April 2017 to November 2019. Hematoxylin-eosin (HE) staining and immunohistochemical staining were used to observe the pathological characteristics and analyze the expression of bcl-2 and bax in the lacrimal gland. RESULTS Compared with normal lacrimal gland tissues, LGPA tumor tissues had obvious changes in pathological morphology. The expression of bcl-2 in LGPA lesion tissues was dramatically higher (P<0.001), the expression of bax was not significantly different between groups (P=0.25), but the ratio of bcl-2/bax was significantly higher in tumor tissues (P=0.01). CONCLUSIONS We found that the lacrimal gland tumor tissues had obvious excessive proliferation in pathomorphology, which revealed the necessity of complete surgical removal of the capsule from the perspective of pathological morphology and provided a theoretical basis for the hypothesis that the imbalance between apoptosis and proliferation could lead to cell hyperproliferation.

Evaluation of FGF10 as a candidate gene for high myopia in a Han Chinese population

Background

Fibroblast growth factor 10 (FGF10) is implicated in the growth and development of the eye. Four singles nucleotide polymorphisms (SNPs) in the FGF10 gene (including rs1384449, rs339501, rs12517396 and rs10462070) were found to be associated with extreme myopia (EM, refractive error ≤ − 10.0 diopters) in Japanese and Chinese Taiwan population. This case-control association study was conducted to explore the relationship between these four SNPs and high myopia in a western Chinese population.

Methods

A total of 869 high myopia patients (HM, including 485 EM patients) and 899 healthy controls were recruited. These four SNPs were genotyped using the ABI SNaPshot method. Five genetic models (allelic, homozygous, heterozygous, dominant, and recessive) were applied to further evaluate the possible correlation between the SNPs and high myopia. The linkage-disequilibrium block (LD) structure was tested by Haploview Software.

Results

In our study, no statistically significant differences were found between HM/EM patients and controls after Bonferroni multiple-correction (P > 0.05) in the allele frequencies of these four SNPs in the FGF10 gene. We further found that rs12517396AA and rs10462070GG carriers showed a decreased risk of HM/EM compared with rs12517396AC + CC and rs10462070GA + AA carriers (P = 0.045, OR = 0.366; P = 0.021, OR = 0.131; P = 0.03, OR = 0.341; P = 0.015, OR = 0.122; respectively). Additionally, rs12517396AA and rs10462070GG carriers showed the same decreased risk of HM/EM compared with rs12517396CC and rs10462070AA carriers (P = 0.048, OR = 0.370; P = 0.023, OR = 0.133; P = 0.032, OR = 0.346; P = 0.017, OR = 0.126). However, these significant associations between rs12517396/rs10462070 and HM/EM disappeared after Bonferroni multiple-correction (P > 0.05).

Conclusion

Our findings indicate that rs12517396 and rs10462070 had marginal association with HM and EM. The other two common polymorphisms in FGF10 unlikely have significant effects in the genetic predisposition to HM/EM in western Chinese population. Further replication studies are needed to validate our findings in both animal models and human genetic epidemiologic studies.

Immunohistochemical features of carcinoma ex pleomorphic adenoma and pleomorphic adenoma in the lacrimal gland

AIM

To investigate C-myc, Ki-67, pan-cytokeratin, and vimentin immunohistochemical features of carcinoma ex pleomorphic adenoma (Ca-ex-PA) and pleomorphic adenoma (PA) in the lacrimal gland in order to find some clues in the differential diagnosis between them.

METHODS

We reviewed microscopic slides and clinical records of 64 cases of PA and 15 cases of Ca-ex-PA in the lacrimal gland. Immunohistochemical antibodies for C-myc, Ki-67, pan-cytokeratin, and vimentin were employed.

RESULTS

Median age of PA was 43.2y (from 21 to 75). The 35 patients (54.7%) were male and 29 patients (45.3%) were female. For the PAs, the average positivity of C-myc was 4.6%; the average proliferation index of Ki-67 was 3.2%; pan-cytokeratin was positive in ductal cells, and vimentin was positive in myoepithelial cells. Median age of Ca-ex-PA was 54.3y (from 26 to 76). There were 7 male patients (46.7%) and 8 female patients (53.3%). Among 15 Ca-ex-PAs, there were 6 myoepithelial carcinomas, 4 adenocarcinomas, 3 epithelial-myoepithelial carcinomas, and 2 squamous cell carcinomas. For the Ca-ex-PAs, the average positivity of C-myc was 36.4%; the average proliferation index of Ki-67 was 29.2%; pan-cytokeratin was positive in all cases, and vimentin was positive in myoepithelial carcinomas.

CONCLUSION

PA has a lower positivity of C-myc and Ki-67, while Ca-ex-PA had a higher positivity of these two biomarkers. These four biomarkers as a set could provide valuable clues in the differential diagnosis between Ca-ex-PA and PA. Our results indicate that the activation of C-myc could play an important role in the pathogenesis of Ca-ex-PA and PA.

Ctenopharyngodon Idella STAT3 alleviates autophagy by up-regulating BCL-2 expression

In mammals, STAT3 (Signal transducer and activator of transcription 3) plays an absolutely vital role in response to cytokines and growth factors. In mammals, IL-6/JAK/STAT3 pathway is closely linked to immune response and promotes cell proliferation, survival and metastasis. Some recent studies have already demonstrated that STAT3 regulates autophagy. As a downstream target gene of STAT3, Bcl-2 (B-cell lymphoma 2) not only participates in regulating apoptosis, but also responds to autophagy. STAT3 regulates autophagy through Bcl-2. In general, the generation of autophagy is always accompanied by the change of apoptosis, and the occurrence of apoptosis is often accompanied by the decreased of cell viability. In grass carp (Ctenopharyngodon idella), LPS-induced autophagy is involved in the release of pro-inflammatory cytokines. However, only the relationship between autophagy and cytokines was illustrated, in which the signaling pathways were not discussed. In the present study, we found that the autophagy inducer, Tunicamycin (Tm), can induce C.Idella Kidney cells (CIK) autophagy. When the cells were incubated with the recombinant human IL-6 (rIL-6) for a short period of times, the mRNA expression level of C.Idella IL-6R and STAT3 were increased. At the same time, the number of GFP-LC3 puncta and the ratio of LC3-II/LC3-I were both decreased obviously in cells. It indicated that the rIL-6 can significantly alleviate autophagy induced by Tm. We speculated that CiSTAT3 may play a key role in the process. To confirm this hypothesis, we performed a rIL-6 activating CiSTAT3 assay. The result demonstrated that rIL-6 can induce CiSTAT3 to form homologous dimmer. The activated CiSTAT3 regulated the transcription activity of CiBcl-2, finally led to a decrease of autophagy. In addition, when cells were in the state of autophagy, apoptosis was increased and cell viability was decreased. When CiSTAT3 was activated, cell apoptosis weakened and cell viability was increased. The results suggest that CiSTAT3 plays an important role in maintaining the normal physiological process of cells.

Recurrent rearrangements of the PLAG1 and HMGA2 genes in lacrimal gland pleomorphic adenoma and carcinoma ex pleomorphic adenoma

PURPOSE

Lacrimal gland tumours constitute a wide spectrum of neoplastic lesions that are histologically similar to tumours of the salivary gland. In the salivary gland, pleomorphic adenoma (PA) is frequently characterized by recurrent chromosomal rearrangements of the PLAG1 and HMGA2 genes, a genetic feature retained in carcinoma ex pleomorphic adenoma (ca-ex-PA) that makes it possible to distinguish ca-ex-PA from de novo carcinomas. However, whether PLAG1 and HMGA2 gene rearrangements are found in lacrimal gland PA and ca-ex-PA is not known.

METHODS

Twenty-one lacrimal gland PAs and four ca-ex-PAs were retrospectively reviewed and subjected to break-apart fluorescence in situ hybridization (FISH) for rearrangements of the PLAG1 gene. Cases without PLAG1 abnormalities were subjected to HMGA2 break-apart FISH. Immunohistochemical staining for PLAG1 and HMGA2 protein was performed and correlated with gene status.

RESULTS

Sixteen of 21 PAs showed rearrangement of PLAG1 and were all positive for PLAG1 protein. Two of the remaining five PAs showed rearrangement of HMGA2 and were the only cases positive for HMGA2 with immunohistochemistry. The three FISH-negative PAs expressed PLAG1 protein. All four ca-ex-PAs showed rearrangement of PLAG1 and expressed PLAG1 protein. None of the de novo carcinomas showed rearrangement of either of the two genes or expression of the two proteins.

CONCLUSION

Rearrangement of PLAG1 and HMGA2 and expression of the corresponding proteins are frequent and specific findings in lacrimal gland PA and ca-ex-PA. The mechanism for PLAG1 overexpression in FISH-negative PAs is yet to be clarified.

Lacrimal gland ductal carcinomas: Clinical, Morphological and Genetic characterization and implications for targeted treatment

PURPOSE

Ductal carcinomas (DCs) of the lacrimal gland are very rare but aggressive malignancies. We investigated DC of the lacrimal gland for potentially clinically actionable targets in the search for new therapeutic options.

METHODS

Case 1: A 77-year-old man, presented with diplopia and xerophtalmia; case 2: A 53-year-old man, presented with headache, proptosis and chemosis and case 3: A 73-year-old man, presenting with chemosis and a corneal abscess. All three cases were characterized morphologically including immunohistochemistry and genetically with fluorescence in situ hybridization (FISH) and one case with next-generation sequencing (NGS) of cancer relevant genes.

RESULTS

Cases 1 and 3 were composed of large, rounded, irregular cystic nodules of carcinoma cells with prominent central comedonecrosis, whereas case 2 had a scirrhous morphology. High expression of CK7, CK19, EMA, p53 and HER2 was characteristic for all three tumours. Androgen receptor was intensely positive in case 1, in scattered cells in case 2 and negative in case 3, whereas oestrogen and progesterone receptor were consistently negative. Genetically, a hemizygous deletion and a point mutation in PTEN were identified in case 1, whereas HER2 amplification was found in cases 2 and 3.

CONCLUSION

This study identified a spectrum of genetic events and pattern of protein expression in DC of the lacrimal gland similar to a subset of carcinomas of the breast and ductal carcinomas of the salivary glands. For therapeutic purposes, aberrations in several components of especially the HER2 signalling pathway could alleviate the effect of HER2-directed therapy illustrating an inadequacy of isolated HER2 testing.

An Update on Tumors of the Lacrimal Gland

Lacrimal gland tumors are rare and constitute a wide spectrum of different entities ranging from benign epithelial and lymphoid lesions to high-grade carcinomas, lymphomas, and sarcomas with large differences in prognosis and clinical management. The symptoms and findings of a lacrimal gland lesion are a growing mass at the site of the lacrimal gland, including displacement of the eyeball, decreased motility, diplopia, and ptosis. Pain is the cardinal symptom of an adenoid cystic carcinoma. Radiological findings characteristically include an oval, well-demarcated mass for benign lesions whereas malignant lesions typically display calcifications, destruction of bone, and invasion of adjacent structures. The diagnosis ultimately relies on histology, as does the choice of treatment and the prognosis. In recent years, the understanding of the biology of numerous types of lacrimal gland neoplasia has improved and the choice of treatment has changed accordingly and holds further promise for future targeted therapies. Treatment of benign epithelial lesions is surgical excision whereas carcinomas often require adjuvant radiotherapy and/or chemotherapy. In contrast, the cornerstone in management of lymphoid lesions is chemotherapy, often including a monoclonal antibody. This article presents an update on the clinical, radiological, histological, and molecular features, along with treatment strategies for tumors of the lacrimal gland.