HES6 enhances the motility of alveolar rhabdomyosarcoma cells

Zebrafish her3 knockout impacts developmental and cancer-related gene signatures

HES3 is a basic helix-loop-helix transcription factor that regulates neural stem cell renewal during development. HES3 overexpression is predictive of reduced overall survival in patients with fusion-positive rhabdomyosarcoma, a pediatric cancer that resembles immature and undifferentiated skeletal muscle. However, the mechanisms of HES3 cooperation in fusion-positive rhabdomyosarcoma are unclear and are likely related to her3/HES3's role in neurogenesis. To investigate HES3's function during development, we generated a zebrafish CRISPR/Cas9 null mutation of her3, the zebrafish ortholog of HES3. Loss of her3 is not embryonic lethal and adults exhibit expected Mendelian ratios. Embryonic her3 zebrafish mutants exhibit dysregulated neurog1 expression, a her3 target gene, and the mutant her3 fails to bind the neurog1 promoter sequence. Further, her3 mutants are significantly smaller than wildtype and a subset present with lens defects as adults. Transcriptomic analysis of her3 mutant embryos indicates that genes involved in organ development, such as pctp and grinab, are significantly downregulated. Further, differentially expressed genes in her3 null mutant embryos are enriched for Hox and Sox10 motifs. Several cancer-related gene pathways are impacted, including the inhibition of matrix metalloproteinases. Altogether, this new model is a powerful system to study her3/HES3-mediated neural development and its misappropriation in cancer contexts.

Single-cell RNA sequencing reveals intratumoral heterogeneity in primary uveal melanomas and identifies HES6 as a driver of the metastatic disease

Intratumor heterogeneity has been recognized in numerous cancers as a major source of metastatic dissemination. In uveal melanomas, the existence and identity of specific subpopulations, their biological function and their contribution to metastasis remain unknown. Here, in multiscale analyses using single-cell RNA sequencing of six different primary uveal melanomas, we uncover an intratumoral heterogeneity at the genomic and transcriptomic level. We identify distinct transcriptional cell states and diverse tumor-associated populations in a subset of the samples. We also decipher a gene regulatory network underlying an invasive and poor prognosis state driven in part by the transcription factor HES6. HES6 heterogenous expression has been validated by RNAscope assays within primary human uveal melanomas, which further unveils the existence of these cells conveying a dismal prognosis in tumors diagnosed with a favorable outcome using bulk analyses. Depletion of HES6 impairs proliferation, migration and metastatic dissemination in vitro and in vivo using the chick chorioallantoic membrane assay, demonstrating the essential role of HES6 in uveal melanomas. Thus, single-cell analysis offers an unprecedented view of primary uveal melanoma heterogeneity, identifies bona fide biomarkers for metastatic cells in the primary tumor, and reveals targetable modules driving growth and metastasis formation. Significantly, our findings demonstrate that HES6 is a valid target to stop uveal melanoma progression.

Rhabdomyosarcoma and Extraosseous Ewing Sarcoma

Rhabdomyosarcoma (RMS) is a malignant tumor that represents the most common form of pediatric soft tissue sarcoma. It arises from mesenchymal origin and forms part of the group of small round blue cell tumors of childhood. It has a constant annual incidence of 4.5 cases per 1,000,000 children. The known histological diagnosis of the two major subtypes (embryonal and alveolar) has been recently enhanced by tumor biological markers and molecular differentiation diagnostic tools that have improved not only the updated classification based on risk stratification, but also the treatment approach based on the clinical group. Ewing sarcoma (ES) is a round cell tumor, highly malignant and poorly differentiated that is currently the second most common malignant bone tumor in children. In rare instances, it develops from an extraskeletal origin, classified as extraosseous Ewing sarcoma (EES). We provide an updated, evidence-based and comprehensive review of the molecular diagnosis, clinical and diagnostic approach and a multidisciplinary medical and surgical management according to the latest standard of care for the treatment of pediatric RMS and EES.

Overexpression of HES6 has prognostic value and promotes metastasis via the Wnt/β-catenin signaling pathway in colorectal cancer

HES6 is a member of the hairy-enhancer of the split homolog family, which has been implicated in oncogenesis and cancer progression in a variety of human cancers, including prostate and breast cancer. However, its clinical significance and biological role in colorectal cancer (CRC) remain unclear. In the present study, the expression of HES6 was significantly upregulated in CRC cell lines and CRC tissues at both the mRNA and protein levels. The present study also reported high expression of HES6 in 138/213 (64.8%) paraffin-embedded archived CRC specimens. HES6 expression was significantly correlated with T classification (P<0.001), N classification (P=0.020), and distant metastasis (P<0.001). Patients with higher HES6 expression levels exhibited a reduced overall survival (P<0.001). In addition, a multivariate analysis revealed that the expression of HES6 may be a novel prognostic marker for the survival of patients with CRC. Furthermore, the present study demonstrated that ectopic expression of HES6 enhanced the migration and invasive abilities of CRC cells. These abilities were significantly inhibited upon knockdown of endogenous HES6 expression by specific short hairpin RNAs. Additionally, the present study reported that the effects of HES6 on metastasis may be associated with the activation of the Wnt/β-catenin signaling pathway. Collectively, the findings of the present study revealed that overexpression of HES6 played a key role in the progression of CRC, leading to a poor prognosis and clinical outcome.

LncSHRG promotes hepatocellular carcinoma progression by activating HES6

Hepatocellular carcinoma, one of the most common cancers, leads to mass mortality worldwide currently. However, the underlying mechanism of its oncogenesis remains to be elucidated. Here we identified that a long noncoding RNA, lncSHRG, was greatly upregulated in human hepatocellular carcinoma samples. We found that lncSHRG was essential for liver cancer cell proliferation and tumor propagation in mice. In mechanism, lncSHRG recruits SATB1 to bind to HES6 promoter and initiates HES6 expression. HES6, which is highly expressed in hepatocellular carcinoma, promotes tumor cell proliferation. High expression level of HES6 is positively correlated with clinical severity and poor prognosis of people with hepatocellular carcinoma. Altogether, our research provides a new insight on the mechanism of hepatocellular carcinoma progression.

State of the art in oncology: high risk neuroblastoma, alveolar rhabdomyosarcoma, desmoplastic small round cell tumor, and POST-TEXT 3 and 4 hepatoblastoma

Despite advances in the treatment of pediatric cancers during the past few decades, high-risk neuroblastoma, alveolar rhabdomyosarcoma, desmoplastic small round cell tumor, and hepatoblastomas with 3 or 4 sector involvement after chemotherapy continue to present significant challenges. This review summarizes recent research on the management of these diseases, with a special focus on the use of surgical debulking, genetic analysis, immunotherapy, and chemotherapy in improving outcomes of patients with these solid tumors.

Transgelin as a therapeutic target to prevent hypoxic pulmonary hypertension

We previously observed that transgelin was preferentially expressed in human pulmonary arterial smooth muscle cells (PAMSCs) under hypoxia and that the upregulation of transgelin was independent of hypoxia-inducible factor 1α (HIF-1α). Reduced transgelin expression was accompanied by significantly impaired migration ability in vitro. However, the regulation mechanism of transgelin and its function in preventing hypoxic pulmonary hypertension (HPH) was unclear. In the present study, RNA interference with hypoxia-inducible factor 2α (HIF-2α) was employed in human PASMCs. Transgelin expression was diminished in HIF-2α-siRNA-treated cells at both the mRNA and protein levels under hypoxia. However, HIF-2α did not transactivate the transgelin promoter directly. TGF-β1 concentration in human PASMCs culture medium was higher under hypoxia, and the accumulated TGF-β1 under hypoxia was regulated by HIF-2α. Furthermore, luciferase and chromatin immunoprecipitation assays indicated that TGF-β1/Smad3 could bind to the transgelin promoter, resulting in increased transgelin expression. In addition to nonintact cellular migration, inhibition of transgelin expression resulted in impaired proliferation in vitro under hypoxia. A lentiviral vector used to inhibit transgelin expression was constructed and intratracheally instilled in rats 3 wk prior to hypoxia treatment. Our final results indicated that inhibition of transgelin expression locally could attenuate increased right ventricular systolic pressure and its associated cardiac and pulmonary vessel remodeling under hypoxia. Our findings indicate that HIF-2α upregulates transgelin indirectly and that accumulated TGF-β1 is a mediator in the upregulation of transgelin by HIF-2α under hypoxia. Inhibition of transgelin expression locally could prevent HPH and pulmonary vascular remodeling in vivo.