RARRES1 inhibits hepatocellular carcinoma progression and increases its sensitivity to lenvatinib through interaction with SPINK2.

BACKGROUND: Lenvatinib is an oral small molecule inhibitor approved for treating patients with unresectable hepatocellular carcinoma (HCC) worldwide. Increasing cell sensitivity to lenvatinib would be an effective method of improving therapeutic efficacy. METHODS: High throughput methods was used to scan the differentially expressed genes (DEGs) related to lenvatinib sensitivity in HCC cells. Gain- and loss-function experiments were used to explore the functions of these DEGs in HCC and lenvatinib sensitivity. CO-IP assay and rescue experiments were utilized to investigate the mechanism. RESULTS: We identified that RAR responder protein 1 (RARRES1), a podocyte-specific growth arrest gene, was among significantly upregulated DEGs in HCC cells following lenvatinib treatment. Functional analysis showed that ectopic RARRES1 expression decreased HCC progression in vitro and in vivo, as well as improving tumor sensitivity to lenvatinib, while RARRES1 silencing increased HCC cell proliferation and migration. Mechanistically, co-immunoprecipitation assays demonstrated that RARRES1 interacted with serine protease inhibitor Kazal-type 2 (SPINK2) in HCC cells. Further, SPINK2 overexpression suppressed HCC cell proliferation and migration, as well as increasing sensitivity to lenvatinib whereas SPINK2 knockdown promoted cell progression and decreased lenvatinib sensitivity. The mRNA and protein levels of RARRES1 and SPINK2 were low in HCC tissue samples, relative to those in normal liver tissue. CONCLUSIONS: Our findings highlighted that RARRES1 can inhibit HCC progression and regulate HCC sensitivity to lenvatinib by interacting SPINK2, representing a new tumor suppressor RARRES1/SPINK2 axis in HCC that modulates sensitivity to lenvatinib.

ETV7 promotes colorectal cancer progression through upregulation of IFIT3.

Members of the E26 transformation-specific (ETS) variant transcription factor family act as either tumor suppressors or oncogenic factors in numerous types of cancer. ETS variant transcription factor 7 (ETV7) participates in the development of malignant tumors, whereas its involvement in colorectal cancer (CRC) is less clear. In this study, The Cancer Genome Atlas (TCGA) and immunochemistry staining were applied to check the clinical relevance of ETV7 and interferon-induced protein with tetratricopeptide repeats 3 (IFIT3) in CRC patients. Overexpression and knockdown of ETV7 and IFIT3 were conducted by transfecting the cells with pCDNA3.1 plasmids and siRNAs, respectively. Western blotting was used to detect the protein expression of ETV7 in CRC cells. Cell Counting Kit-8, cell colony formation, and Transwell assays, as well as flow cytometry, were used to evaluate the proliferation, migration, cell cycle, and apoptosis of CRC cells. Furthermore, western blotting, RT-qPCR, and luciferase assay were used to explore the regulation of ETV7 on IFIT3. Rescue assay was used to investigate the significance of ETV7/IFIT3 axis on CRC progression. We found that ETV7 was upregulated in CRC tissues and cells. Overexpression of ETV7 stimulated the proliferation, migration, and cell cycle amplification, and reduced the apoptosis of CRC cells. Downregulation of ETV7 exerted the opposite effect on CRC cell progression. Moreover, we demonstrated that ETV7 stimulated the transcription activity, the mRNA and protein expression of IFIT3 in CRC cells. There was a positive correlation between ETV7 and IFIT3 in CRC patients. IFIT3 knockdown reversed the promotive effect exerted by overexpression of ETV7 on the amplification and migration of CRC cells. By contrast, overexpression of IFIT3 blocked the inhibitory effect of ETV7-targeting siRNA. In summary, ETV7 induces progression of CRC by activating the transcriptional expression of IFIT3. The EVT7/IFIT3 axis may be a novel target for CRC therapy.