Arf6 regulates RhoB subcellular localization to control cancer cell invasion

Zaoui, Kossay; Rajadurai, Charles V.; Duhamel, Stéphanie; Park, Morag

doi:10.1083/jcb.201806111

Cited by 20 publications

(20 citation statements)

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“…Moreover, mevalonate pathway activity is essential for the activation of ARF6 by external ligands [ 17 ]. It has also been reported by other research groups that ARF6 is involved in maintenance of the Warburg effect, to meet the unusual nutrient/energy demands of cancer cells [ 18 ], in the trafficking of pre-miRNA complexes to sites of microvesicle biogenesis [ 19 ], and their RhoB-mediated subcellular targeting to endosomes, and for the various biological functions of cancer cells [ 20 ]. AMAP1 may also directly bind to actin filaments to bundle them to be an integral part of the actin stress fiber organization [ 21 ].…”

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confidence: 99%

Inhibition of mutant KRAS-driven overexpression of ARF6 and MYC by an eIF4A inhibitor drug improves the effects of anti-PD-1 immunotherapy for pancreatic cancer

et al. 2021

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Many clinical trials are being conducted to clarify effective combinations of various drugs for immune checkpoint blockade (ICB) therapy. However, although extensive studies from multiple aspects have been conducted regarding treatments for pancreatic ductal adenocarcinoma (PDAC), there are still no effective ICB-based therapies or biomarkers for this cancer type. A series of our studies have identified that the small GTPase ARF6 and its downstream effector AMAP1 (also called ASAP1/DDEF1) are often overexpressed in different cancers, including PDAC, and closely correlate with poor patient survival. Mechanistically, the ARF6-AMAP1 pathway drives cancer cell invasion and immune evasion, via upregulating β1-integrins and PD-L1, and downregulating E-cadherin, upon ARF6 activation by external ligands. Moreover, the ARF6-AMAP1 pathway enhances the fibrosis caused by PDAC, which is another barrier for ICB therapies. KRAS mutations are prevalent in PDACs. We have shown previously that oncogenic KRAS mutations are the major cause of the aberrant overexpression of ARF6 and AMAP1, in which KRAS signaling enhances eukaryotic initiation factor 4A (eIF4A)-dependent ARF6 mRNA translation and eIF4E-dependent AMAP1 mRNA translation. MYC overexpression is also a key pathway in driving cancer malignancy. MYC mRNA is also known to be under the control of eIF4A, and the eIF4A inhibitor silvestrol suppresses MYC and ARF6 expression. Using a KPC mouse model of human PDAC (LSL-Kras(G12D/+); LSL-Trp53(R172H/+)); Pdx-1-Cre), we here demonstrate that inhibition of the ARF6-AMAP1 pathway by shRNAs in cancer cells results in therapeutic synergy with an anti-PD-1 antibody in vivo; and furthermore, that silvestrol improves the efficacy of anti-PD-1 therapy, whereas silvestrol on its own promotes tumor growth in vivo. ARF6 and MYC are both essential for normal cell functions. We demonstrate that silvestrol substantially mitigates the overexpression of ARF6 and MYC in KRAS-mutated cells, whereas the suppression is moderate in KRAS-intact cells. We propose that targeting eIF4A, as well as mutant KRAS, provides novel methods to improve the efficacy of anti-PD-1 and associated ICB therapies against PDACs, in which ARF6 and AMAP1 overexpression, as well as KRAS mutations of cancer cells are biomarkers to identify patients with drug-susceptible disease. The same may be applicable to other cancers with KRAS mutations.

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mentioning

confidence: 99%

Inhibition of mutant KRAS-driven overexpression of ARF6 and MYC by an eIF4A inhibitor drug improves the effects of anti-PD-1 immunotherapy for pancreatic cancer

et al. 2021

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“…Depleted proteins suggesting altered transport along the axon in Ki91 included proteins interacting or forming dynactin complex, required for mitochondria and endosome/lysosome and synaptic vesicles transport along the axons, such as Actr1a and Ank2 ( Holleran et al, 1996 ; Moughamian et al, 2013 ; Lorenzo et al, 2014 ). Besides, there were also essential cytoskeletal proteins involved in regulating axonal transport and actin dynamics, Arf6 and its interactor RhoB, targeted by Arf6 to endosomes ( Eva et al, 2017 ; Zaoui et al, 2019 ). Components of SNAREs responsible for vesicular trafficking were also depleted in SCA3 axons, such as Napa (a.k.a.…”

Section: Discussionmentioning

confidence: 99%

Broad Influence of Mutant Ataxin-3 on the Proteome of the Adult Brain, Young Neurons, and Axons Reveals Central Molecular Processes and Biomarkers in SCA3/MJD Using Knock-In Mouse Model

Wiatr

Marczak

Pérot

et al. 2021

Front. Mol. Neurosci.

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Spinocerebellar ataxia type 3 (SCA3/MJD) is caused by CAG expansion mutation resulting in a long polyQ domain in mutant ataxin-3. The mutant protein is a special type of protease, deubiquitinase, which may indicate its prominent impact on the regulation of cellular proteins levels and activity. Yet, the global model picture of SCA3 disease progression on the protein level, molecular pathways in the brain, and neurons, is largely unknown. Here, we investigated the molecular SCA3 mechanism using an interdisciplinary research paradigm combining behavioral and molecular aspects of SCA3 in the knock-in ki91 model. We used the behavior, brain magnetic resonance imaging (MRI) and brain tissue examination to correlate the disease stages with brain proteomics, precise axonal proteomics, neuronal energy recordings, and labeling of vesicles. We have demonstrated that altered metabolic and mitochondrial proteins in the brain and the lack of weight gain in Ki91 SCA3/MJD mice is reflected by the failure of energy metabolism recorded in neonatal SCA3 cerebellar neurons. We have determined that further, during disease progression, proteins responsible for metabolism, cytoskeletal architecture, vesicular, and axonal transport are disturbed, revealing axons as one of the essential cell compartments in SCA3 pathogenesis. Therefore we focus on SCA3 pathogenesis in axonal and somatodendritic compartments revealing highly increased axonal localization of protein synthesis machinery, including ribosomes, translation factors, and RNA binding proteins, while the level of proteins responsible for cellular transport and mitochondria was decreased. We demonstrate the accumulation of axonal vesicles in neonatal SCA3 cerebellar neurons and increased phosphorylation of SMI-312 positive adult cerebellar axons, which indicate axonal dysfunction in SCA3. In summary, the SCA3 disease mechanism is based on the broad influence of mutant ataxin-3 on the neuronal proteome. Processes central in our SCA3 model include disturbed localization of proteins between axonal and somatodendritic compartment, early neuronal energy deficit, altered neuronal cytoskeletal structure, an overabundance of various components of protein synthesis machinery in axons.

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“…Notably, Arf6 depletion impaired endosomal localization of RhoB followed by its degradation through an endolysosomal pathway. Most importantly, Arf6 or RhoB depletion enhanced the c-Met-dependent 3D migration of invasive breast cancer cells [164]. In sum, RhoB appears to play a general role in the trafficking decisions of diverse membrane-associated proteins, including RTKs, adhesion receptors, and signaling molecules, such as Src and GTPase family members, which together influence the cancer cell phenotype.…”

Section: Rho Gtpases and Membrane Trafficking-implications For Cancermentioning

confidence: 92%

Spatiotemporal Control of Intracellular Membrane Trafficking by Rho GTPases

Noll

Haußer

2019

Cells

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As membrane-associated master regulators of cytoskeletal remodeling, Rho GTPases coordinate a wide range of biological processes such as cell adhesion, motility, and polarity. In the last years, Rho GTPases have also been recognized to control intracellular membrane sorting and trafficking steps directly; however, how Rho GTPase signaling is regulated at endomembranes is still poorly understood. In this review, we will specifically address the local Rho GTPase pools coordinating intracellular membrane trafficking with a focus on the endo-and exocytic pathways. We will further highlight the spatiotemporal molecular regulation of Rho signaling at endomembrane sites through Rho regulatory proteins, the GEFs and GAPs. Finally, we will discuss the contribution of dysregulated Rho signaling emanating from endomembranes to the development and progression of cancer.an inactive GDP-bound and an active GTP-bound state. Rho GDP/GTP cycling is tightly regulated by guanine nucleotide exchange factors (GEFs) that promote the formation of the active GTP-bound form through exchanging GDP for GTP. On the contrary, GTPase-activating proteins (GAPs) catalyze the intrinsic GTPase activity and promote the formation of inactive GDP-bound Rho. This inactive state can be subsequently recognized by guanine nucleotide dissociation inhibitors (GDIs), which sequester Rho GTPases in the cytosol [5,6] (Figure 1). Whereas classical Rho GTPases are regulated by GDP/GTP cycling, atypical Rho GTPases are regulated by other mechanisms that occur in particular at the transcriptional and post-translational level [7]. In the case of atypical Rho GTPases, GTP is usually constitutively bound, either because these Rho GTPases possess high intrinsic nucleotide exchange activity or have substitutions in their GTPase domain that prevent GTP hydrolysis.

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Arf6 regulates RhoB subcellular localization to control cancer cell invasion

Cited by 20 publications

References 73 publications

Inhibition of mutant KRAS-driven overexpression of ARF6 and MYC by an eIF4A inhibitor drug improves the effects of anti-PD-1 immunotherapy for pancreatic cancer

Inhibition of mutant KRAS-driven overexpression of ARF6 and MYC by an eIF4A inhibitor drug improves the effects of anti-PD-1 immunotherapy for pancreatic cancer

Broad Influence of Mutant Ataxin-3 on the Proteome of the Adult Brain, Young Neurons, and Axons Reveals Central Molecular Processes and Biomarkers in SCA3/MJD Using Knock-In Mouse Model

Spatiotemporal Control of Intracellular Membrane Trafficking by Rho GTPases

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