Correction to: N-Myc promotes therapeutic resistance development of neuroendocrine prostate cancer by differentially regulating miR-421/ ATM pathway

Mir-421 and mir-550a-1 are potential prognostic markers in esophageal adenocarcinoma

OBJECTIVE

To identify the prognostic indicators of esophageal adenocarcinoma (EAC) for future EAC diagnosis and treatment.

METHODS

The EAC dataset from The Cancer Genome Atlas was screened for differentially expressed microRNAs (miRNAs) and mRNAs associated with EAC. Weighted gene coexpression network analysis was performed to cluster miRNAs or mRNA with similar expression patterns to identify the miRNAs or mRNA that are highly associated with EAC. Prognostic miRNAs for overall survival (OS) were identified using Cox proportional-hazards regression analysis and least absolute shrinkage and selection operator based on survival duration and status. Two types of miRNAs were selected to develop a prognostic signature model for EAC using multiple Cox regression analysis. Furthermore, the signature was validated using internal validation sets 1 and 2. The receiver operating characteristic curve and concordance index were used to evaluate the accuracy of the signature and validation sets. The expression of miR-421, miR-550a-3p, and miR-550a-5p was assessed using quantitative polymerase chain reaction (qPCR). The proliferation, invasion, and migration of EAC cells were assessed using CCK8 and transwell assays. The OS of target mRNAs was assessed using Kaplan-Meier analysis. Functional enrichment analysis of the target mRNAs was performed using Metascape.

RESULTS

The prognostic signature and validation sets comprising mir-421 and mir-550a-1 had favorable predictive power in OS. Compared with the patients with EAC in the high-expression group, those assigned to the low-expression group displayed increased OS according to survival analysis. Differential and qPCR analysis showed that miR-421, miR-550a-3p, and miR-550a-5p were highly expressed in the EAC tissues and cell lines. Moreover, the downregulation of miR-421 and miR-550a-3p with inhibitor markedly suppressed the proliferation, invasion, and migration in OE33 cells compared with the negative control. A total of 20 target mRNAs of three miRNAs were predicted, among which seven target mRNAs-ASAP3, BCL2L2, LMF1, PPM1L, PTPN21, SLC18A2, and NR3C2-had prognostic value; PRKACB, PDCD4, RPS6KA5, and BCL2L2 were enriched in the miRNA cancer pathway.

CONCLUSION

Prognostic indicators of EAC may be useful in future EAC diagnosis and treatment.

CRISPR technology: A versatile tool to model, screen, and reverse drug resistance in cancer

BACKGROUND

Drug resistance is a serious challenge in cancer treatment that can render chemotherapy a failure. Understanding the mechanisms behind drug resistance and developing novel therapeutic approaches are cardinal steps in overcoming this issue. Clustered regularly interspaced short palindrome repeats (CRISPR) gene-editing technology has proven to be a useful tool to study cancer drug resistance mechanisms and target the responsible genes. In this review, we evaluated original research studies that used the CRISPR tool in three areas related to drug resistance, namely screening resistance-related genes, generating modified models of resistant cells and animals, and removing resistance by genetic manipulation. We reported the targeted genes, study models, and drug groups in these studies. In addition to discussing different applications of CRISPR technology in cancer drug resistance, we analyzed drug resistance mechanisms and provided examples of CRISPR's role in studying them. Although CRISPR is a powerful tool for examining drug resistance and sensitizing resistant cells to chemotherapy, more studies are required to overcome its disadvantages, such as off-target effects, immunotoxicity, and inefficient delivery of CRISPR/cas9 into the cells.

Androgen Receptor-Dependent Mechanisms Mediating Drug Resistance in Prostate Cancer

Androgen receptor (AR) is a main driver of prostate cancer (PCa) growth and progression as well as the key drug target. Appropriate PCa treatments differ depending on the stage of cancer at diagnosis. Although androgen deprivation therapy (ADT) of PCa is initially effective, eventually tumors develop resistance to the drug within 2-3 years of treatment onset leading to castration resistant PCa (CRPC). Castration resistance is usually mediated by reactivation of AR signaling. Eventually, PCa develops additional resistance towards treatment with AR antagonists that occur regularly, also mostly due to bypass mechanisms that activate AR signaling. This tumor evolution with selection upon therapy is presumably based on a high degree of tumor heterogenicity and plasticity that allows PCa cells to proliferate and develop adaptive signaling to the treatment and evolve pathways in therapy resistance, including resistance to chemotherapy. The therapy-resistant PCa phenotype is associated with more aggressiveness and increased metastatic ability. By far, drug resistance remains a major cause of PCa treatment failure and lethality. In this review, various acquired and intrinsic mechanisms that are AR‑dependent and contribute to PCa drug resistance will be discussed.

A potential new role of ATM inhibitor in radiotherapy: suppressing ionizing Radiation-Activated EGFR

Purpose: Although EGFR inhibitor (EGFRi) is used in cancer therapy to suppress tumor growth and resistance to treatment including radiotherapy, EGFRi resistance frequently developed, which significantly reduced treatment outcomes. Therefore, developing alternative approaches for EGFRi is of great importance. Based on our recent observation that ATM inhibitor (ATMi) efficiently inhibited ionizing radiation (IR)-induced EGFR activation in mouse embryo fibroblasts (MEF), the main purpose of this study is to determine whether ATMi could inhibit IR-induced EGFR activation in human tumor cell lines and explore its potential in EGFRi-alternative therapies.Materials and methods: We compared the effects of ATMi, EGFRi individually or in combination on IR-induced EGFR phosphorylation, cell growth and radio-sensitization in nine human tumor cell lines including lung adenocarcinoma (A549 and H358), glioblastoma (LN229), cervical cancer (HeLa), colorectal carcinoma (SW480 and HCT116) and nasopharygeal carcinoma (5-8 F, 6-10B and HK1) cell lines. In addition, we detected the effects of ATMi, EGFRi alone or both on the efficiency of non-homologous end-joining (NHEJ) and homologous recombination (HR) using I-SceI -GFP based NHEJ or HR reporter cell lines.Results: Compared to EGFRi treatment, ATMi treatment decreased IR-induced EGFR phosphorylation, suppressed growth and increased IR sensitization in tested cell lines at a similar or even more efficient level. Combining ATMi and EGFRi did not significantly increased the effects on these phenotypes as ATMi treatment alone. Also, similar to ATMi, EGFRi mainly reduced the efficiency of HR but not NHEJ although combining ATMi and EGFRi further inhibited the HR efficiency.Conclusions: Our study demonstrates that ATMi can function like EGFRi in human tumor cells to inhibit tumor cell growth and sensitize the tumor cells to IR, suggesting that ATMi treatment as an alternative approach may exert anticancer effects on EGFRi-resistant tumor cells and facilitate radiotherapy.