The Role of ARF Family Proteins and Their Regulators and Effectors in Cancer Progression: A Therapeutic Perspective

Abstract

The Adenosine diphosphate-Ribosylation Factor (ARF) family belongs to the RAS superfamily of small GTPases and is involved in a wide variety of physiological processes, such as cell proliferation, motility and differentiation by regulating membrane traffic and associating with the cytoskeleton. Like other members of the RAS superfamily, ARF family proteins are activated by Guanine nucleotide Exchange Factors (GEFs) and inactivated by GTPase-Activating Proteins (GAPs). When active, they bind effectors, which mediate downstream functions. Several studies have reported that cancer cells are able to subvert membrane traffic regulators to enhance migration and invasion. Indeed, members of the ARF family, including ARF-Like (ARL) proteins have been implicated in tumorigenesis and progression of several types of cancer. Here, we review the role of ARF family members, their GEFs/GAPs and effectors in tumorigenesis and cancer progression, highlighting the ones that can have a pro-oncogenic behavior or function as tumor suppressors. Moreover, we propose possible mechanisms and approaches to target these proteins, toward the development of novel therapeutic strategies to impair tumor progression.

Keywords: ARL; GTPase-activating protein; guanine nucleotide exchange factor; invasion; membrane traffic; migration; tumorigenesis.

FIGURE 1

Putative therapeutic strategies to target ARF proteins, GEFs, GAPs and effectors. (A) In the case of ARF family members that can act as oncogenes, their expression or activity could be downregulated (1); GEF activity or expression downregulated (2); ARF-GEF binding blocked or nucleotide binding blocked (3); active ARF binding to membranes (4) or effectors blocked (5); effector function impaired (6); GAP expression or activity upregulated (7). (B) Regarding ARF proteins that can act as tumor suppressors, their expression or activity could be upregulated (1); GEF activity or expression upregulated (2); GAP activity or expression downregulated (3).