Novel gene markers of immunosuppressive chemicals in mouse lymph node assay

SRSF7 is a promising prognostic biomarker in hepatocellular carcinoma and is associated with immune infiltration

BACKGROUND

Previous studies indicate that the splicing process, regulated by the cellular machinery of tumors (spliceosome), undergoes alterations, leading to oncogenic splicing events associated with the progression of tumors towards aggressiveness. However, the role of serine/arginine-rich splicing factor 7 (SRSF7) in hepatocellular carcinoma (HCC) and the tumor microenvironment (TME) remains unclear.

METHODS

This study was aimed to explore the role and clinical significance of SRSF7 in HCC. By conducting functional analysis and gene set enrichment analysis, it was discovered that SRSF7 contributes to multiple pathways associated with immune response and tumor advancement. Further experiments verified that silencing of SRSF7 obviously inhibits progression of HCC.

RESULTS

Aberrant expression of SRSF7, which were referred as an independent prognostic risk factor, effectively predicts the prognosis of patients with HCC. Functional and gene enrichment analyses revealed that SRSF7 is linked with multiple immune and tumor progression-related pathways, including the B cell receptor signaling pathway, positive regulation of leukocyte and immunoglobulin receptor binding cell activation, nuclear division, membrane invagination, cell cycle, as well as mTOR signaling pathway. Furthermore, increased SRSF7 expression was associated with tumor-infiltrating inflammatory cells (CD4+, monocytes/macrophages, CD8 + and endothelial). Additionally, multiple immune checkpoint genes were markedly positively related to SRSF7. The efficiency of SRSF7 in predicting immunomodulator and chemokine responses were also assessed in microenvironment. Moreover, in vitro analyses demonstrated that knockdown of SRSF7 suppressed the malignant evolution of HCC possibly by deactivating the PI3K/AKT/mTOR signaling.

CONCLUSION

The role of SRSF7 in the tumor microenvironment has been successfully assessed. It may be a valid bio-index for predicting the HCC prognosis, thereby guiding individualized immunotherapy for cancer.

Immunosuppressive potential of bardoxolone methyl using a modified murine local lymph node assay (LLNA)

2-Cyano-3, 12-dioxooleana-1, 9-dien-28-oic acid methyl ester (CDDO-Me; bardoxolone methyl) is one of the synthetic oleanane triterpenoids (SOs). It is known that it is the strongest Nrf2/ARE signaling inducer of SOs and slightly inhibits immune response. Little was known about the immunomodulatory action of CDDO-Me in vivo. We assessed its immunosuppressive potential by using the modified mouse lymph node assay (LLNA) including immunosuppression-related gene expression analysis. In the modified LLNA, CDDO-Me showed a significant decrease in lymph node weight and changes in expressions of the immunosuppression-related genes, Zfp459 and Fmo2. It has been already reported that a decrease in lymph node weight was induced by several types of immunosuppressive chemicals such as calcineurin inhibitors, antimetabolites, steroids, and alkylators. In addition, changes in Zfp459 and Fmo2 expression was reported in response after only treatment of antimetabolites. From these results, CDDO-Me is considered to have an immunosuppressive action and similar mechanism to antimetabolites.

Biological influence of Hakai in cancer: a 10-year review

In order to metastasize, cancer cells must first detach from the primary tumor, migrate, invade through tissues, and attach to a second site. Hakai was discovered as an E3 ubiquitin-ligase that mediates the posttranslational downregulation of E-cadherin, a major component of adherens junctions in epithelial cells that is characterized as a potent tumor suppressor and is modulated during various processes including epithelial–mesenchymal transition. Recent data have provided evidences for novel biological functional role of Hakai during tumor progression and other diseases. Here, we will review the knowledge that has been accumulated since Hakai discovery 10 years ago and its implication in human cancer disease. We will highlight the different signaling pathways leading to the influence on Hakai and suggest its potential usefulness as therapeutic target for cancer.