RESUMO
BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is frequently diagnosed and treated in advanced tumor stages with poor prognosis. More effective screening programs and novel therapeutic means are urgently needed. Recent studies have regarded tight junction protein claudin 18.2 (CLDN18.2) as a candidate target for cancer treatment, and zolbetuximab (formerly known as IMAB362) has been developed against CLDN18.2. However, there are few data reported thus far related to the clinicopathological characteristics of CLDN18.2 expression for PDAC. AIM: To investigate the expression of CLDN18.2 in PDAC patients and subsequently propose a new target for the treatment of PDAC. METHODS: The Cancer Genome Atlas, Genotype-Tissue Expression, Gene Expression Omnibus, and European Genome-phenome Archive databases were first employed to analyze the CLDN18 gene expression in normal pancreatic tissue compared to that in pancreatic cancer tissue. Second, we analyzed the expression of CLDN18.2 in 93 primary PDACs, 86 para-cancer tissues, and 13 normal pancreatic tissues by immunohistochemistry. Immunostained tissues were assessed applying the histoscore. subsequently, they fell into two groups according to the expression state of CLDN18.2. Furthermore, the correlations between CLDN18.2 expression and diverse clinicopathological characteristics, including survival, were investigated. RESULTS: The gene expression of CLDN18 was statistically higher (P < 0.01) in pancreatic tumors than in normal tissues. However, there was no significant correlation between CLDN18 expression and survival in pancreatic cancer patients. CLDN18.2 was expressed in 88 (94.6%) of the reported PDACs. Among these tumors, 50 (56.8%) cases showed strong immunostaining. The para-cancer tissues were positive in 81 (94.2%) cases, among which 32 (39.5%) of cases were characterized for strong staining intensities. Normal pancreatic tissue was identified solely via weak immunostaining. Finally, CLDN18.2 expression significantly correlated with lymph node metastasis, distant metastasis, nerve invasion, stage, and survival of PDAC patients, while there was no correlation between CLDN18.2 expression and localization, tumor size, patient age and sex, nor any other clinicopathological characteristic. CONCLUSION: CLDN18.2 expression is frequently increased in PDAC patients. Thus, it may act as a potential therapeutic target for zolbetuximab in PDAC.
RESUMO
Gastric cancer (GC) is one of the most common malignancies of the digestive system worldwide. Multiple long noncoding RNAs (lncRNAs) participate in the regulation of GC development and metastasis. In this study, we aimed to elucidate the expression and function of lncRNA IGFL2-AS1 in GC. We found that IGFL2-AS1 was highly expressed in GC tissues and cell lines. Knockdown of IGFL2-AS1 suppressed GC cell proliferation, migration, and invasion in vitro. Furthermore, we identified that IGFL2-AS1 exerted its function as a molecular sponge of miR-802. MiR-802 was demonstrated to be a tumor suppressor, and overexpression of miR-802 suppressed GC cell growth, migration, and invasion. Mechanistically, we revealed that the cAMP-regulated phosphoprotein 19 (ARPP19) was a direct target of miR-802 and could reverse the inhibitory function of miR-802. Moreover, our results confirmed that knockdown of IGFL2-AS1 inhibited GC tumor development in an in vivo GC tumor xenograft model. In summary, our data suggest that the IGFL2-AS1/miR-802/ARPP19 axis plays a critical role in the progression and metastasis of GC. Therapies targeting the IGFL2-AS1/miR-802/ARPP19 axis can potentially improve GC treatment.
