Related Experiment Video

Updated: Oct 2, 2026

Focus Formation: A Cell-based Assay to Determine the Oncogenic Potential of a Gene
08:18

Focus Formation: A Cell-based Assay to Determine the Oncogenic Potential of a Gene

Published on: December 31, 2014

Cellular ras gene activity is required for full neoplastic transformation by the large tumor antigen of SV40

L Raptis1, H L Brownell, M J Corbley

  • 1Department of Microbiology and Immunology, Queen's University, Kingston, Ontario, Canada. raptisl@post.queensu.ca

Cell Growth & Differentiation : the Molecular Biology Journal of the American Association for Cancer Research
|August 1, 1997
PubMed

Insights

The cellular ras (c-Ras) gene product is essential for full neoplastic transformation by the SV40 large tumor antigen (SVLT). Down-regulating c-Ras activity reduced soft agar colony formation and tumorigenicity in nude mice.

Area of Science:

  • Oncology
  • Molecular Biology
  • Virology

Background:

  • The SV40 large tumor antigen (SVLT) is known to induce neoplastic transformation in cells.
  • The role of the cellular ras (c-Ras) gene product in this process requires further elucidation.
  • Understanding the interplay between SVLT and c-Ras is crucial for cancer research.

Purpose of the Study:

  • To investigate the specific role of the c-Ras gene product in SVLT-induced neoplastic transformation.
  • To determine if c-Ras activity is necessary for all aspects of SVLT-mediated transformation.

Main Methods:

  • Murine C3H10T1/2 cells were manipulated to reduce c-Ras activity using antisense ras gene constructs or a dominant-negative ras mutant.
  • Cells were analyzed for morphological transformation, soft agar colony formation, and tumorigenicity in nude mice following SVLT expression.
  • c-Ras activity was quantified by measuring the Ras-bound GTP/GTP + GDP ratio.

Main Results:

  • SVLT-induced morphological transformation was not affected by decreased c-Ras activity.
  • However, colony formation in soft agar and tumorigenicity were significantly reduced in c-Ras-deficient cells.
  • SVLT expression led to an observable increase in cellular c-Ras activity.

Conclusions:

  • The c-Ras gene product is not essential for the initial morphological changes induced by SVLT.
  • c-Ras activity is critically required for the sustained growth and tumorigenic potential associated with SVLT transformation.
  • These findings highlight a specific requirement for c-Ras in the later stages of SVLT-driven neoplastic transformation.

More Related Videos

An Oncogenic Hepatocyte-Induced Orthotopic Mouse Model of Hepatocellular Cancer Arising in the Setting of Hepatic Inflammation and Fibrosis00:06

An Oncogenic Hepatocyte-Induced Orthotopic Mouse Model of Hepatocellular Cancer Arising in the Setting of Hepatic Inflammation and Fibrosis

Published on: September 12, 2019

Identification of EGFR and RAS Inhibitors using Caenorhabditis elegans08:12

Identification of EGFR and RAS Inhibitors using Caenorhabditis elegans

Published on: October 5, 2020

Related Concept Videos

Abnormal Proliferation02:23

Abnormal Proliferation

Under normal conditions, most adult cells remain in a non-proliferative state unless stimulated by internal or external factors to replace lost cells. Abnormal cell proliferation is a condition in which the cell's growth exceeds and is uncoordinated with normal cells. In such situations, cell division persists in the same excessive manner even after cessation of the stimuli, leading to persistent tumors. The tumor arises from the damaged cells that replicate to pass the damage to the daughter...
The Ras Gene02:38

The Ras Gene

The Ras-gene-encoded proteins are regulators of signaling pathways controlling cell proliferation, differentiation, or cell survival. The Ras-gene family in humans constitutes three primary members—the HRas, NRas, and KRas. These genes code for four functionally distinct yet closely related proteins—the HRas, NRas, KRas4A, and KRas4B. The involvement of mutant Ras genes in human cancer was first discovered in 1982 and is among the most common causes of human tumorigenesis.
Ras is a superfamily...
Rous Sarcoma Virus (RSV) and Cancer01:03

Rous Sarcoma Virus (RSV) and Cancer

Rous Sarcoma virus or RSV was discovered by F. Peyton Rous in the year 1911 as a filterable transmissible agent that could cause tumors in chickens. He won a Nobel Prize for this discovery in 1966. His experiments clearly demonstrated that some cancers could be caused by infectious agents and led to the discovery of many more cancer-causing viruses in animals as well as humans.
RSV is a retrovirus that contains two copies of a plus-strand  RNA genome. Its genome consists of four main open...
Small GTPases - Ras and Rho01:24

Small GTPases - Ras and Rho

Ras and Rho are small monomeric GTPases that act downstream of receptor tyrosine kinase (RTK) and regulate various cellular processes. These GTPases switch between active and inactive states by binding to guanine nucleotides.
Three regulatory proteins control their activity:
Rous Sarcoma Virus (RSV) and Cancer01:03

Rous Sarcoma Virus (RSV) and Cancer

Rous Sarcoma virus or RSV was discovered by F. Peyton Rous in the year 1911 as a filterable transmissible agent that could cause tumors in chickens. He won a Nobel Prize for this discovery in 1966. His experiments clearly demonstrated that some cancers could be caused by infectious agents and led to the discovery of many more cancer-causing viruses in animals as well as humans.
RSV is a retrovirus that contains two copies of a plus-strand  RNA genome. Its genome consists of four main open...
The Ras Gene02:38

The Ras Gene

The Ras-gene-encoded proteins are regulators of signaling pathways controlling cell proliferation, differentiation, or cell survival. The Ras-gene family in humans constitutes three primary members—the HRas, NRas, and KRas. These genes code for four functionally distinct yet closely related proteins—the HRas, NRas, KRas4A, and KRas4B. The involvement of mutant Ras genes in human cancer was first discovered in 1982 and is among the most common causes of human tumorigenesis.
Ras is a superfamily...