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Triple-negative breast cancer (TNBC) is an aggressive, difficult-to-treat subtype of cancer with a poor prognosis; there is an urgent need for effective, targeted molecular therapies. The cyclin D/cyclin-dependent kinase (CDK)4/6–retinoblastoma protein (Rb) pathway plays a critical role in regulating cell cycle checkpoints, a process which is often disrupted in cancer cells. Selective CDK4/6 inhibitors can prevent retinoblastoma protein phosphorylation by invoking cell cycle arrest in the first growth phase (G1), and may therefore represent an effective treatment option. In this article, we review the molecular mechanisms and therapeutic efficacy of CDK4/6 inhibitors in combination with other targeted therapies for the treatment of triple-negative breast cancer. Three selective CDK4/6 inhibitors have so far received the approval of the Food and Drug Administration (FDA) for patients with estrogen receptor (ER)+/human epidermal growth factor receptor 2 (HER2) breast cancer. Trilaciclib, a small molecule short-acting inhibitor of CDK4/6, has also been approved recently for people with small cell lung cancer, and is also expected to be clinically effective against breast cancer. Although the efficacy of CDK4/6 inhibitors in patients with triple-negative breast cancer remains uncertain, their use in conjunction with other targeted therapies may improve outcomes and is therefore currently being explored. Identifying biomarkers for response or resistance to CDK4/6 inhibitor treatment may optimize the personalization of treatment strategies for this disease. Ongoing and future clinical trials and biomarker studies will shed further light on these topics, and help to realize the full potential of CDK4/6 inhibitor treatment in triple-negative breast cancer.

Non-small cell lung cancer (NSCLC) represents one of the primary causes of cancer-related mortality all over the world. Following our initial finding of the upregulated expression of E2F transcription factor-1 (E2F1) in the NSCLC-related microarray, this study aimed to explore the regulatory role of E2F1 and underlying mechanism in NSCLC development. NSCLC cell viability, migration, and invasion were evaluated utilizing Cell Counting Kit 8 (CCK-8), 5-ethynyl-2′-deoxyuridine (EdU), wound-healing, and Transwell assays. Loss- and gain-function assays were performed to determine the effects of the fat mass and obesity-associated protein (FTO)/E2F1/neural epidermal growth factor-like 2 (NELL2) axis on NSCLC cell behaviors in vitro and NSCLC tumor growth in vivo . E2F1 was highly expressed in both NSCLC tissues and cells. E2F1 augmented the viability, migration, and invasion of NSCLC cells, which was attributable to E2F1 transcriptionally activating NELL2. FTO upregulated the expression of E2F1 by inhibiting the m6A modification of E2F1. The FTO/E2F1/NELL2 axis modulated NSCLC cell viability, migration, and invasion in vitro as well as affected NSCLC tumor growth and metastasis in vivo . The FTO/E2F1/NELL2 axis may impart pro-tumorigenic effects on the cell behavior of NSCLC cells and thus accelerate NSCLC progression.

Background: The aim of this study was to investigate the prognostic significance of faciogenital dysplasia 6 (FGD6) in gastric cancer (GC).Methods: The data of GC patients from The Cancer Genome Atlas (TCGA) database were used for the primary study. Then, our data were validated by the GEO database and RuiJin cohort. The relationship between the FGD6 level and various clinicopathological features was analyzed by logistic regression and univariate Cox regression. Multivariate Cox regression analysis was used to evaluate whether FGD6 was an independent prognostic factor for survival of patients with GC. The relationship between FGD6 and overall survival time was explored by the Kaplan–Meier method. In addition, gene set enrichment analysis (GSEA) was performed to investigate the possible biological processes of FGD6.Results: The FGD6 level was significantly overexpressed in GC tissues, compared with adjacent normal tissues. The high expression of FGD6 was related to a high histological grade, stage, and T classification and poor prognosis of GC. Multivariate Cox regression analysis showed that FGD6 was an independent prognostic factor for survival of patients with GC. GSEA identified that the high expression of FGD6 was mainly enriched in regulation of actin cytoskeleton.Conclusion: FGD6 may be a prognostic biomarker for predicting the outcome of patients with GC.

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