Small extrachromosomal circular DNA harboring targeted tumor suppressor gene mutations supports intratumor heterogeneity in mouse liver cancer induced by multiplexed CRISPR/Cas9

Extrachromosomal circular DNA-related SPOCK1 contributes to development and enzalutamide resistance of prostate cancer by regulating epithelial mesenchymal transition

Prostate cancer is a significant contributor to cancer-related mortality, and the tumor typically develops into castration-resistant prostate cancer (CRPC). Hence, few effective clinical strategies are available to patients with advanced disease. Extrachromosomal circular DNA (eccDNA) is a type of circular DNA originating from the chromosomes but is likely independent of them. Because of its unique structural characteristics, eccDNA has extensive applications as a new biomarker for cancer prevention and treatment. Circle-seq obtains a comprehensive picture of the overall landscape of eccDNA sizes and content in cell populations. In this study, we used Circle-seq and studied the distribution pattern and expression level of eccDNA in prostate cancer. We confirmed that eccDNA is derived from every human chromosome and has sequences from all known types of genomic structures, revealing it is a common mutational element in prostate cancer. We also identified an eccDNA-related gene SPOCK1 that promotes drug resistance, proliferation, and metastasis of many cancers through the epithelial-mesenchymal transition (EMT) mechanism. The SPOCK1-associated eccDNA was highly upregulated in various groups of sequencing results, and SPOCK1 was highly expressed in prostate cancer tissues and cells. Therefore, SPOCK1 exists as eccDNA in prostate cancer and encourages its development and drug resistance via the EMT mechanism. Our results suggest that upregulated genes in the form of eccDNA are oncogenes in prostate cancer and play a pivotal role in carcinogenesis.

Transcription factor ZEB1 coordinating with NuRD complex to promote oncogenesis through glycolysis in colorectal cancer

Background

Colorectal cancer (CRC) is an aggressive primary intestinal malignancy with the third-highest incidence and second-highest mortality among all cancer types worldwide. Transcription factors (TFs) regulate cell development and differentiation owing to their ability to recognize specific DNA sequences upstream of genes. Numerous studies have demonstrated a strong correlation between TFs, the etiology of tumors, and therapeutic approaches. Here, we aimed to explore prognosis-related TFs and comprehend their carcinogenic mechanisms, thereby offering novel insights into the diagnosis and management of CRC.

Materials and Methods

Differentially expressed TFs between CRC and normal tissues were identified leveraging The Cancer Genome Atlas database, Weighted correlation network analysis and Cox regression analysis were performed to identify prognosis-related TFs. The cellular functions of hub TF zinc finger E-box binding homeobox 1 (ZEB1) were determined using by 5-ethynyl-2'-deoxyuridine and cell invasion assays in CRC cells. RNA-sequencing, Kyoto Encyclopedia of Genes and Genomes enrichment, and gene set enrichment analyses were used to identify the cellular processes in which ZEB1 participates. Immunoaffinity purification, silver staining mass spectrometry, and a chromatin immunoprecipitation assay were conducted to search for proteins that might interact with ZEB1 and the target genes they jointly regulate.

Results

Thirteen central TFs related to prognosis were identified through bioinformatics analysis techniques. Among these TFs, ZEB1 emerged as the TF most closely associated with CRC, as determined through a combination of regulatory network diagrams, survival curves, and phenotype analyses. ZEB1 promotes CRC cell growth by recruiting the NuRD(MTA1) complex, and the ZEB1/NuRD(MTA1) complex transcriptionally represses glycolysis-associated tumor suppressor genes.

Conclusion

Our study not only identified a hub biomarker related to CRC prognosis but also revealed the specific molecular mechanisms through which ZEB1 affects cancer progression. These insights provide crucial evidence for the diagnosis of CRC and potential treatment opportunities.

Preclinical Anticipation of On- and Off-Target Resistance Mechanisms to Anti-Cancer Drugs: A Systematic Review

The advent of targeted therapies has led to tremendous improvements in treatment options and their outcomes in the field of oncology. Yet, many cancers outsmart precision drugs by developing on-target or off-target resistance mechanisms. Gaining the ability to resist treatment is the rule rather than the exception in tumors, and it remains a major healthcare challenge to achieve long-lasting remission in most cancer patients. Here, we discuss emerging strategies that take advantage of innovative high-throughput screening technologies to anticipate on- and off-target resistance mechanisms before they occur in treated cancer patients. We divide the methods into non-systematic approaches, such as random mutagenesis or long-term drug treatment, and systematic approaches, relying on the clustered regularly interspaced short palindromic repeats (CRISPR) system, saturated mutagenesis, or computational methods. All these new developments, especially genome-wide CRISPR-based screening platforms, have significantly accelerated the processes for identification of the mechanisms responsible for cancer drug resistance and opened up new avenues for future treatments.