Characterization of prognostic value and immunological roles of RAB22A in hepatocellular carcinoma

[Effects of LncRNA SNHG20 on epithelial mesenchymal transition and microtubule formation in human oral squamous cell carcinoma cells through targeted regulation of the miR-520c-3p/RAB22A pathway]

OBJECTIVE

To investigate the effects of LncRNA SNHG20 on epithelial mesenchymal transition (EMT) and microtubule formation in human oral squamous cell carcinoma (OSCC) cells through targeted regulation of the miR-520c-3p/RAB22A pathway.

METHODS

After real-time fluorescence quantitative detection of LncRNA SNHG20, miR-520c-3p, RAB22A mRNA expression levels in OSCC tissues and cells, dual luciferase reporter assay was used to detect the relationship between the three. OSCC cells were randomly separated into control group, sh-NC group, sh-SNHG20 group, sh-SNHG20+anti NC group, and sh-SNHG20+anti miR-520c-3p group. Western blotting was used to detect the expression of N-cadherin, vimentin, and E-cadherin proteins in the OSCC cells. The morphology of HSC-3 cells was observed under microscope. Changes in the number of microtubules formed were detected. The effect of LncRNA SNHG20 on the growth of OSCC tumors and the expression levels of LncRNA SNHG20, miR-520c-3p and RAB22 A in the transplanted tumors were detected by nude mice tumorigenesis experiment.

RESULTS

LncRNA SNHG20 and RAB22A mRNA were upregulated in the OSCC tissues and cells, while miR-520c-3p was downregulated (P < 0.05). There were binding sites between LncRNA SNHG20 and miR-520c-3p, RAB22A and miR-520c-3p, which had targeted regulation relationship. Compared with the sh-NC group, the sh-SNHG20 group had fewer stromal like cells, more epithelial like cells, incomplete microtubule structure, and fewer nodules. LncRNA SNHG20, RAB22A, N-Cadherin, and vimentin were downregulated, while miR-520c-3p and E-cadherin were upregulated (P < 0.05). Compared with the sh-SNHG20+anti-NC group, the sh-SNHG20+anti-miR-520c-3p group had a higher number of stromal like cells, a lower number of epithelioid cells, tighter microtubule arrangement, and more microtubule nodules. miR-520c-3p and E-cadherin were downregulated, while RAB22A, N-cadherin, and vimentin were upregulated (P < 0.05). The transplanted tumor of OSCC in sh-SNHG20 group was smaller and lower than that in sh-NC group. The expression levels of LncRNA SNHG20 and RAB22A in the transplanted tumor tissues were lower than those in sh-NC group, and the expression level of miR-520c-3p was higher than that in sh-NC group (P < 0.05).

CONCLUSION

LncRNA SNHG20 promotes epithelial-mesenchymal transition and microtubule formation in human oral squamous cell carcinoma cells by targeting the miR-520c-3p/RAB22A pathway. Inhibiting the expression of LncRNA SNHG20 can target and regulate the miR-520c-3p/RAB22A pathway to inhibit EMT and microtubule formation in OSCC cells.

RAB22A as a predictor of exosome secretion in the progression and relapse of multiple myeloma

BACKGROUND

Multiple myeloma (MM) is an incurable malignant plasma cell disease. We explored the role of RAB22A in exosome secretion, epithelial-mesenchymal transition (EMT) and immune regulation.

METHODS

We obtained MM samples from Gene Expression Omnibus (GEO) data sets. We downloaded the "IOBR" package, and used the "PCA" and "ssGSEA" algorithms to calculate the EMT scores and exosome scores. The "CIBERSORT" package was used to analyze the infiltration of immune cells. We extracted the exosomes of mesenchymal stem cell (MSC) to verify the biological function of RAB22A.

RESULTS

The expression level of RAB22A in smoldering multiple myeloma (SMM) and MM patients was significantly higher than that in normal people and monoclonal gammopathy of undetermined significance (MGUS) patients, and the expression level of RAB22A in relapse MM patients was significantly higher than that in newly diagnosed patients. The EMT scores and exosome scores of high RAB22A group were significantly higher than those of low RAB22A group, and the exosome scores of MSC in recurrent patients were significantly higher than those of newly diagnosed patients. In addition, the infiltration levels of monocyte, NK cells resting, eosinophils, T cells regulatory and T cells CD4 memory activated were positively correlated with RAB22A. After down-regulating the expression of RAB22A in MM-MSC, the secretion of exosomes decreased. Compared with the exosomes of MSC in si-RAB22A group, the exosomes in control group significantly promoted the proliferation of MM.

CONCLUSIONS

RAB22A is a potential therapeutic target to improve the prognosis of MM, which is closely related to exosome secretion, EMT and immune cell infiltration.

AP4M1 as a prognostic biomarker associated with cell proliferation, migration and immune regulation in hepatocellular carcinoma

BACKGROUND

AP4M1 is a protein-coding gene that plays a crucial role in transporter activity, recognition, and hereditary-associated diseases, but it's largely unknown in cancers.

METHODS

The expression level of AP4M1 in cancers was investigated by The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases, and the correlation between AP4M1 and hepatocellular carcinoma (HCC) clinicopathological parameters were analyzed. Univariate and multifactorial COX regression analyses were performed to clarify the prognostic value of AP4M1 in HCC. The correlation between AP4M1 and immune cell infiltration was analyzed using single-sample Gene Set Enrichment Analysis (ssGSEA). Besides, we verified the biological function of AP4M1 by applying Cell Counting Kit-8 (CCK8), colony formation, and transwell assays.

RESULTS

The expression of AP4M1 was significantly elevated in HCC and was correlated with patients' pathological grades, AFP, and BMI. Kaplan-Meier survival curves indicated that patients with AP4M1 overexpression had worse overall survival. Univariate and multivariate COX regression analyses showed that AP4M1 was an independent risk factor affecting the prognosis of HCC. In addition, we observed that AP4M1 positively correlated with most immune checkpoint suppressor genes in HCC. Moreover, in vitro experiments further confirmed that AP4M1 could promote the proliferation and invasion of HCC.

CONCLUSIONS

AP4M1 is highly expressed and associated with poor prognosis in HCC. AP4M1 is closely related to cancer-immune regulation and could be a novel target for HCC, and guiding new strategies for the diagnosis and treatment of HCC patients.

Endocytosis in cancer and cancer therapy

Endocytosis is a complex process whereby cell surface proteins, lipids and fluid from the extracellular environment are packaged, sorted and internalized into cells. Endocytosis is also a mechanism of drug internalization into cells. There are multiple routes of endocytosis that determine the fate of molecules, from degradation in the lysosomes to recycling back to the plasma membrane. The overall rates of endocytosis and temporal regulation of molecules transiting through endocytic pathways are also intricately linked with signalling outcomes. This process relies on an array of factors, such as intrinsic amino acid motifs and post-translational modifications. Endocytosis is frequently disrupted in cancer. These disruptions lead to inappropriate retention of receptor tyrosine kinases on the tumour cell membrane, changes in the recycling of oncogenic molecules, defective signalling feedback loops and loss of cell polarity. In the past decade, endocytosis has emerged as a pivotal regulator of nutrient scavenging, response to and regulation of immune surveillance and tumour immune evasion, tumour metastasis and therapeutic drug delivery. This Review summarizes and integrates these advances into the understanding of endocytosis in cancer. The potential to regulate these pathways in the clinic to improve cancer therapy is also discussed.