Oncoviruses and Pathogenic MicroRNAs in Humans

Area of Science:

• Oncology
• Molecular Biology
• Virology

Background:

• The role of oncoviral integration loci in cancer development (oncogenesis) is not fully understood.
• While some viral integration sites produce non-coding transcripts, microRNAs (miRNAs) have been identified within these loci.
• miRNAs are small, non-coding RNAs that regulate gene expression and are implicated in human cancers.

Purpose of the Study:

• To review the potential oncogenic or tumor-suppressive roles of miRNAs, particularly those originating from oncoviral integration sites.
• To explore the concept of miRNAs as mobile genetic elements in the context of cancer.
• To establish that alterations in cellular miRNA profiles can be classified as tumorigenic or tumor suppressive.

Main Methods:

• Literature review and synthesis of existing research on miRNAs, viral integration, and cancer.
• Analysis of studies identifying miRNAs in oncoviral integration loci.
• Examination of evidence linking miRNA dysregulation to tumorigenesis and tumor suppression.

Main Results:

• Both cellular and virally-derived miRNAs from integration sites show potential for promoting human tumorigenesis.
• Dysregulation of miRNA profiles is a key factor in defining cells as either cancerous or tumor-suppressive.
• Virally-pathogenic miRNAs can contribute to oncogenesis or oncogene suppression, supporting the 'RNA wave' hypothesis.

Conclusions:

• Alterations in miRNA profiles are critical determinants of tumorigenic or tumor-suppressive cellular states.
• Virally-encoded miRNAs represent a significant factor in oncogenesis and oncogene suppression.
• miRNAs are hypothesized to function as mobile genetic elements, influencing cancer progression.