Contextual role of E2F1 in suppression of melanoma cell motility and invasiveness

E2F transcription factor 1 as a potential prognostic biomarker and promotes tumor proliferation in skin cutaneous melanoma

Cutaneous melanoma (SKCM) is a highly aggressive malignancy with an overall poor prognosis. The expression of E2F transcription factor 1 in SKCM tissues was analyzed using the data acquired from the Cancer Genome Atlas (TCGA)and Gene Expression Omnibus (GEO)databases. The expression of E2F1 was also analyzed in human biopsies using immunohistology, and its expression was detected in SKCM cell lines using qPCR and WB technology. The prognostic value of E2F transcription factor 1 in SKCM was investigated using Kaplan-Meier survival and Cox analysis. The Tumor Immunization Estimation Resource (TIMER) was used to analyze the invasion of immune cells and associated markers of immune cells. The prognostic value of E2F transcription factor 1 DNA methylation levels for each CpG was analyzed by means of the MethSurv. The results were verified in the Human Protein Atlas (HPA) database. Individuals with elevated E2F transcription factor 1 expression had a worse prognosis (HR=1.43, p = 0.01). Using the expression level of E2F transcription factor 1, a reliable distinction between tumor and normal tissues can be made (Area Under the Curve =0.949). Moreover, immune infiltrations analysis showed that the mRNA expression levels and somatic copy number alterations (SCNA) in E2F transcription factor 1 were significantly correlated with recruitment of several immune cells. Our study showed that overexpression of E2F transcription factor 1 was significantly associated with poor prognosis and malignant phenotype of melanoma cells in SKCM patients.

Dual Inhibition of SYK and EGFR Overcomes Chemoresistance by Inhibiting CDC6 and Blocking DNA Replication

Targeting multiple signaling pathways has been proposed as a strategy to overcome resistance to single-pathway inhibition in cancer therapy. A previous study in epithelial ovarian cancers identified hyperactivity of spleen tyrosine kinase (SYK) and EGFR, which mutually phosphorylate and activate each other. Given the potential for pharmacologic inhibition of both kinases with clinically available agents, this study aimed to assess the antitumor efficacy of both pharmacologic and genetic SYK and EGFR coinhibition using a multifaceted approach. We assessed the coinactivation effects in chemoresistant ovarian cancer cell lines, patient-derived organoids, and xenograft models. Dual inhibition of SYK and EGFR in chemoresistant ovarian cancer cells elicited a synergistic antitumor effect. Notably, the combined inhibition activated the DNA damage response, induced G1 cell-cycle arrest, and promoted apoptosis. The phosphoproteomic analysis revealed that perturbation of SYK and EGFR signaling induced a significant reduction in both phosphorylated and total protein levels of cell division cycle 6, a crucial initiator of DNA replication. Together, this study provides preclinical evidence supporting dual inhibition of SYK and EGFR as a promising treatment for chemoresistant ovarian cancer by disrupting DNA synthesis and impairing formation of the prereplication complex. These findings warrant further clinical investigation to explore the potential of this combination therapy in overcoming drug resistance and improving patient outcomes. Significance: SYK and EGFR coinhibition exerts synergistic anticancer effects in chemoresistant ovarian cancer, providing a strategy to treat chemotherapy-resistant ovarian cancers using clinically available agents by targeting critical signaling pathways involved in DNA replication.

The Molecular Context of Vulnerability for CDK9 Suppression in Triple Wild-Type Melanoma

Approximately half of melanoma tumors lack a druggable target and are unresponsive to current targeted therapeutics. One proposed approach for treating these therapeutically orphaned tumors is by targeting transcriptional dependencies (oncogene starvation), whereby survival factors are depleted through inhibition of transcriptional regulators. A drug screen identified a CDK9 inhibitor (SNS-032) to have therapeutic selectivity against wild-type (wt) BRAF^wt/NRAS^wt melanomas compared with BRAF^mut/NRAS^mut mutated melanomas. We then used two strategies to inhibit CDK9 in vitro-a CDK9 degrader (TS-032) and a selective CDK9 kinase inhibitor (NVP-2). At 500 nM, both TS-032 and NVP-2 demonstrated greater suppression of BRAF^wt/NRAS^wt/NF1^wt cutaneous and uveal melanomas than mutant melanomas. RNA sequencing analysis of eight melanoma lines with NVP-2 treatment demonstrated that the context of this vulnerability appears to converge on a cell cycle network that includes many transcriptional regulators, such as the E2F family members. The Cancer Genome Atlas human melanoma tumor data further supported a potential oncogenic role for E2F1 and E2F2 in BRAF^wt/NRAS^wt/NF1^wt tumors and a direct link to CDK9. Our results suggest that transcriptional blockade through selective targeting of CDK9 is an effective method of suppressing therapeutically orphaned BRAF/NRAS/NF1 wt melanomas.

Essential Oils and Their Main Chemical Components: The Past 20 Years of Preclinical Studies in Melanoma

Simple Summary

In the last years, targeted therapy and immunotherapy modified the landscape for metastatic melanoma treatment. These therapeutic approaches led to an impressive improvement in patients overall survival. Unfortunately, the emergence of drug resistance and side effects occurring during therapy strongly limit the long-term efficacy of such treatments. Several preclinical studies demonstrate the efficacy of essential oils as antitumoral agents, and clinical trials support their use to reduce side effects emerging during therapy. In this review we have summarized studies describing the molecular mechanism through which essential oils induce in vitro and in vivo cell death in melanoma models. We also pointed to clinical trials investigating the use of essential oils in reducing the side effects experienced by cancer patients or those undergoing anticancer therapy. From this review emerged that further studies are necessary to validate the effectiveness of essential oils for the management of melanoma.

Abstract

The last two decades have seen the development of effective therapies, which have saved the lives of a large number of melanoma patients. However, therapeutic options are still limited for patients without BRAF mutations or in relapse from current treatments, and severe side effects often occur during therapy. Thus, additional insights to improve treatment efficacy with the aim to decrease the likelihood of chemoresistance, as well as reducing side effects of current therapies, are required. Natural products offer great opportunities for the discovery of antineoplastic drugs, and still represent a useful source of novel molecules. Among them, essential oils, representing the volatile fraction of aromatic plants, are always being actively investigated by several research groups and show promising biological activities for their use as complementary or alternative medicine for several diseases, including cancer. In this review, we focused on studies reporting the mechanism through which essential oils exert antitumor action in preclinical wild type or mutant BRAF melanoma models. We also discussed the latest use of essential oils in improving cancer patients’ quality of life. As evidenced by the many studies listed in this review, through their effect on apoptosis and tumor progression-associated properties, essential oils can therefore be considered as potential natural pharmaceutical resources for cancer management.