SLC17A9 expression levels in a pan‑cancer panel and validation of the role of SLC17A9 as a novel prognostic biomarker for osteosarcoma

Our plain-English summary of SLC17A9 expression levels in a pan‑cancer panel and validation of the role of SLC17A9 as a novel prognostic biomarker for osteosarcoma, by J. Li, F. Wu, L. Su, et al (Oncology Letters, 2023).

The study

• Authors: J. Li, F. Wu, L. Su, H. Zhu, J. Yao, M. Zhang
• Journal: Oncology Letters
• Published: 2023;26(3):383
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Previous studies have demonstrated the involvement of the solute carrier family 17 member 9 (SLC17A9) in certain types of cancer; however, the precise role of SLC17A9 is not well defined. In the present study, a comprehensive analysis was performed to determine the involvement of SLC17A9 in a pan-cancer panel. First, data on SLC17A9 expression levels from publicly available databases were obtained to determine SLC17A9 expression profiles in various types of cancer. Next, the involvement of SLC17A9 in the prognosis of patients, stemness indices and the immune microenvironment was examined in 34 types of cancer. Furthermore, CCK-8 and colony-formation assays were performed to determine the effect of SLC17A9 on osteosarcoma (OSS) cells. In a pan-cancer panel, a difference in SLC17A9 expression levels was observed in the tumor tissues as compared with healthy tissues. Furthermore, survival analysis revealed a significant association between SLC17A9 expression levels and the prognosis of patients with various cancer types, including adrenocortical carcinoma, kidney renal clear cell carcinoma, glioblastoma, kidney renal papillary cell carcinoma, low grade glioma, liver hepatocellular carcinoma, mesothelioma, lung adenocarcinoma, skin cutaneous melanoma, uveal melanoma, stomach adenocarcinoma and OSS. The results of the present study revealed correlations between stemness indices, tumor immunity and SLC17A9 expression levels. Furthermore, univariate and multivariate Cox regression analyses indicated that SLC17A9 may be utilized as an independent risk factor for overall survival of patients with OSS. In vitro experiments demonstrated that SLC17A9 promotes the proliferation and viability of OSS cells. Taken together, the results of the present study suggest an association between SLC17A9 and the prognosis of patients as well as tumor immunity in various cancer types. SLC17A9 may serve as a novel prognostic biomarker and target for improving the prognosis of patients with OSS.

Copyright: © Li et al.

In plain English

This was a laboratory and public-database study of a gene called SLC17A9 across 34 cancer types. It did not study asbestos. The authors used gene and survival data from The Cancer Genome Atlas and related databases, and tested the gene in osteosarcoma (bone cancer) cell lines. SLC17A9 levels were significantly higher in tumor than in normal tissue in 15 cancer types and lower in adrenocortical carcinoma. In single-factor (univariate) analyses, SLC17A9 levels were associated with overall survival and with disease-specific survival in several cancers, including mesothelioma (type not specified). The text gives no direction, size or patient numbers for the mesothelioma association. In mesothelioma, SLC17A9 levels correlated positively with a DNA-based 'stemness' score and with immune and stromal scores. In osteosarcoma patients, high levels went with poorer overall survival. Lowering SLC17A9 in HOS cells reduced their growth, and raising it in MG63 cells increased growth. The authors concluded that SLC17A9 acts as a tumor promoter in osteosarcoma and may be a prognostic biomarker. They noted that the databases mainly included Caucasian patients.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Bioinformatic analysis of public cancer databases across 34 cancer types, plus in vitro experiments on osteosarcoma cell lines
• Who was studied: Patient tumor and normal-tissue data for 34 cancer types from public databases (TCGA, TARGET, Genotype-Tissue Expression, GEPIA; numbers not given in the text), and the osteosarcoma cell lines U2OS, Saos2, MG63, HOS and 143B
• Exposure: No asbestos or other environmental exposure was studied. The factor examined was expression of the SLC17A9 gene, including knockdown and overexpression in cells.
• Main results:
  • SLC17A9 expression was significantly increased in tumor tissue in 15 cancer types (mesothelioma not among those listed) and significantly decreased in adrenocortical carcinoma (ACC)
  • In univariate Cox regression, SLC17A9 expression was associated with overall survival in several cancers, including mesothelioma (MESO). No hazard ratios are given in the text.
  • SLC17A9 expression was associated with disease-specific survival in several cancers, including mesothelioma (MESO)
  • In Kaplan-Meier analysis, high SLC17A9 expression went with shorter overall survival in KIRC, LGG, osteosarcoma and UVM, and longer overall survival in BRCA
  • In mesothelioma (among other cancers), SLC17A9 expression correlated positively with the DNA methylation-based stemness index, and also with immune and stromal scores
  • In osteosarcoma patients in the TCGA-TARGET data, SLC17A9 may be an independent risk factor for overall survival
  • Knocking down SLC17A9 reduced proliferation of HOS osteosarcoma cells, and overexpressing it increased proliferation of MG63 cells
• The authors' conclusion: The authors concluded that SLC17A9 functions as a tumor promoter in osteosarcoma and may be a novel prognostic biomarker and a potential target for synergistic immunotherapy of osteosarcoma.
• Limitations the authors state:
  • The public databases mainly included patients of Caucasian ethnicity, which may cause bias
  • The effect of SLC17A9 protein expression in multiple cancer types was not determined
  • The underlying mechanisms of SLC17A9's role remain to be elucidated

Topics

Medical terms in this study, explained in our Lexicon: Biomarker, Prognosis, Carcinoma, Mesothelioma, Lung Adenocarcinoma, Adenocarcinoma, Overall Survival.

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