bims-pimaco 2022-01-16 papers

bims-pimaco

Biomed News

on PI3K and MAPK signalling in colorectal cancer

Issue of 2022‒01‒16
twelve papers selected by
Lucas B. Zeiger
Beatson Institute for Cancer Research

Precision Targeting of Mutant PI3Kα in Cancer by Selective Degradation.
Allele-specific endogenous tagging and quantitative analysis of β-catenin in colorectal cancer cells.
THEM6-mediated reprogramming of lipid metabolism supports treatment resistance in prostate cancer.
Next Generation Sequencing of Circulating Tumor DNA Can Optimize Second Line Treatment in RAS Wild Type Metastatic Colorectal Cancer after Progression on Anti-EGFR Therapy: Time to Rethink Our Approach.
CDC42 controlled apical-basal polarity regulates intestinal stem cell to transit amplifying cell fate transition via YAP-EGF-mTOR signaling.
Reconstruction and exploratory analysis of mTORC1 signalling pathway and its applications to various diseases using Network based approach.
Targeting the undruggable oncogenic KRAS: the dawn of hope.
PP2A-dependent TFEB activation is blocked by PIKfyve-induced mTORC1 activity.
Upregulation of CD36, a Fatty Acid Translocase, Promotes Colorectal Cancer Metastasis by Increasing MMP28 and Decreasing E-Cadherin Expression.
Efficient targeted oncogenic KRASG12C degradation via first reversible-covalent PROTAC.
The Timing and Duration of Folate Restriction Differentially Impacts Colon Carcinogenesis.
GqPCR-stimulated dephosphorylation of AKT is induced by an IGBP1-mediated PP2A switch.

Cancer Discov. 2022 Jan;12(1): 20-22

Precision Targeting of Mutant PI3Kα in Cancer by Selective Degradation.

Bart Vanhaesebroeck, John E Burke, Ralitsa R Madsen.

PIK3CA, which encodes the p110α catalytic subunit of PI3Kα, is one of the most frequently genetically activated kinases in solid tumors. In this issue of Cancer Discovery, Song and colleagues report that the related PI3Kα inhibitors taselisib and inavolisib trigger receptor tyrosine kinase (RTK)-dependent degradation of the mutant p110α protein in breast cancer cells that are positive for HER2 RTK, limiting feedback-mediated drug resistance and potentially widening the therapeutic index of PI3Kα inhibition.See related article by Song et al., p. 204.

DOI: https://doi.org/10.1158/2159-8290.CD-21-1411
Elife. 2022 Jan 11. pii: e64498. [Epub ahead of print]11

Allele-specific endogenous tagging and quantitative analysis of β-catenin in colorectal cancer cells.

Giulia Ambrosi, Oksana Voloshanenko, Antonia F Eckert, Dominique Kranz, G Ulrich Nienhaus, Michael Boutros.

  Wnt signaling plays important roles in development, homeostasis, and tumorigenesis. Mutations in β-catenin that activate Wnt signaling have been found in colorectal and hepatocellular carcinomas. However, the dynamics of wild-type and mutant forms of β-catenin are not fully understood. Here, we genome-engineered fluorescently tagged alleles of endogenous β-catenin in a colorectal cancer cell line. Wild-type and oncogenic mutant alleles were tagged with different fluorescent proteins, enabling the analysis of both variants in the same cell. We analyzed the properties of both β-catenin alleles using immunoprecipitation, immunofluorescence, and fluorescence correlation spectroscopy approaches, revealing distinctly different biophysical properties. In addition, activation of Wnt signaling by treatment with a GSK3β inhibitor or a truncating APC mutation modulated the wild-type allele to mimic the properties of the mutant β-catenin allele. The one-step tagging strategy demonstrates how genome engineering can be employed for the parallel functional analysis of different genetic variants.

Keywords:  FCS; Wnt signaling; cancer; cell biology; crispr; ctnnb1; endogenous tagging; fluorescence correlation spectroscopy; genetics; genomics; human; oncogenic signaling; β-catenin

DOI:  https://doi.org/10.7554/eLife.64498
EMBO Mol Med. 2022 Jan 11. e14764

THEM6-mediated reprogramming of lipid metabolism supports treatment resistance in prostate cancer.

Arnaud Blomme, Coralie Peter, Ernest Mui, Giovanny Rodriguez Blanco, Ning An, Louise M Mason, Lauren E Jamieson, Grace H McGregor, Sergio Lilla, Chara Ntala, Rachana Patel, Marc Thiry, Sonia H Y Kung, Marine Leclercq, Catriona A Ford, Linda K Rushworth, David J McGarry, Susan Mason, Peter Repiscak, Colin Nixon, Mark J Salji, Elke Markert, Gillian M MacKay, Jurre J Kamphorst, Duncan Graham, Karen Faulds, Ladan Fazli, Martin E Gleave, Edward Avezov, Joanne Edwards, Huabing Yin, David Sumpton, Karen Blyth, Pierre Close, Daniel J Murphy, Sara Zanivan, Hing Y Leung.

  Despite the clinical benefit of androgen-deprivation therapy (ADT), the majority of patients with advanced prostate cancer (PCa) ultimately develop lethal castration-resistant prostate cancer (CRPC). In this study, we identified thioesterase superfamily member 6 (THEM6) as a marker of ADT resistance in PCa. THEM6 deletion reduces in vivo tumour growth and restores castration sensitivity in orthograft models of CRPC. Mechanistically, we show that the ER membrane-associated protein THEM6 regulates intracellular levels of ether lipids and is essential to trigger the induction of the ER stress response (UPR). Consequently, THEM6 loss in CRPC cells significantly alters ER function, reducing de novo sterol biosynthesis and preventing lipid-mediated activation of ATF4. Finally, we demonstrate that high THEM6 expression is associated with poor survival and correlates with high levels of UPR activation in PCa patients. Altogether, our results highlight THEM6 as a novel driver of therapy resistance in PCa as well as a promising target for the treatment of CRPC.

Keywords:  ATF4; ER stress; lipid metabolism; prostate cancer; therapy resistance

DOI:  https://doi.org/10.15252/emmm.202114764
Oncol Res Treat. 2022 Jan 09.

Next Generation Sequencing of Circulating Tumor DNA Can Optimize Second Line Treatment in RAS Wild Type Metastatic Colorectal Cancer after Progression on Anti-EGFR Therapy: Time to Rethink Our Approach.

Davide Mauri, Konstantinos Kamposioras, Dimitris Matthaios, Maria Tolia, Ioanna Nixon, Mario Dambrosio, George Zarkavelis, Konstantinos Papadimitriou, Branka Petricevic, Pantelis Kountourakis, Jindrich Kopecky, Cvetka Grašič Kuhar, Lazar Popovic, Nataliya P Chilingirova, Ramon Andrade De Mello, Natalija Dedic, Konstantinos Katsanos, Bianca Mostert, Filippo Alongi, Berardino de Bari, Stefanie Corradini, Eleytherios Kampletsas, Ioanna Gazouli, Stefania Gkoura, Anna-Lea Amylidi, Antonios Valachis.

Background Management of Raswild-type colorectal cancer (CRC) patients upon disease progression after the successful use of targeted treatment with anti-EGFR monoclonal antibodies and backbone chemotherapy remains a clinical challenge. Development of treatment resistance with prevalence of pre-existing RAS mutated clones, RAS mutation conversion, truncation of extracellular receptor domains as well as HER2 and MET amplification are molecular events that can be difficult to follow without the use of sophisticated laboratory techniques. Summary The clinical hurdle of re-biopsy and tumor heterogeneity can be overcome by the implementation Next Generation Sequencing (NGS) to analyze circulating tumor DNA (ctDNA) and identify drugable mutations or recovery of RAS-wildness. In this opinion paper we summarize with critical thinking the clinical approach to be followed after the failure of first line treatment in Ras wild-type CRC tumors with the use of NGS. Key Messages Rechallenge with anti-EGFR inhibitors, in case of persistent or recovery of Ras wildness, and targeted approach of specific mutations (BRAF inhibitors) amplifications (anti-Her2 treatment) or fusion proteins (NTRK inhibitors) can by guided by the use of NGS. The use of NGS platforms for serial analysis of ctDNA is an important step to better understand the molecular landscape of metastatic colorectal cancer and guide clinical decisions. NGS should be considered a mainstay in clinical practice for the management of CRC patients and health authorities should consider reimbursing its use in the appropriate clinical settings.

DOI: https://doi.org/10.1159/000521845
Cell Rep. 2022 Jan 11. pii: S2211-1247(21)01487-X. [Epub ahead of print]38(2): 110009

CDC42 controlled apical-basal polarity regulates intestinal stem cell to transit amplifying cell fate transition via YAP-EGF-mTOR signaling.

Zheng Zhang, Feng Zhang, Ashley Kuenzi Davis, Mei Xin, Gerd Walz, Weidong Tian, Yi Zheng.

  Epithelial polarity is controlled by a polarity machinery that includes Rho GTPase CDC42 and Scribble/PAR. By using intestinal stem cell (ISC)-specific deletion of CDC42 in olfactomedin-4 (Olfm4)-internal ribosome entry site (IRES)-EGFP/CreERT2;CDC42flox/flox mice, we find that CDC42 loss initiated in the ISCs causes a drastic hyperproliferation of transit amplifying (TA) cells and disrupts epithelial polarity. CDC42-null crypts display expanded TA cell and diminished ISC populations, accompanied by elevated Hippo signaling via YAP/TAZ-Ereg (yes-associated protein/WW domain-containing transcription regulator protein 1-epiregulin) and mechanistic target of rapamycin (mTOR) activation, independent from canonical Wnt signaling. YAP/TAZ conditional knockout (KO) restores the balance of ISC/TA cell populations and crypt proliferation but does not rescue the polarity in CDC42-null small intestine. mTOR or epidermal growth factor receptor (EGFR) inhibitor treatment of CDC42 KO mice exhibits similar rescuing effects without affecting YAP/TAZ signaling. Inducible ablation of Scribble in intestinal epithelial cells mimics that of CDC42 KO defects, including crypt hyperplasia and Hippo signaling activation. Mammalian epithelial polarity regulates ISC/TA cell fate and proliferation via a Hippo-Ereg-mTOR cascade.

Keywords:  Cdc42; Hippo signaling; cell fate; intestinal stem cells; mTOR signaling; mouse model; polarity

DOI:  https://doi.org/10.1016/j.celrep.2021.110009
J Microbiol Biotechnol. 2022 Jan 08. 32(3):

Reconstruction and exploratory analysis of mTORC1 signalling pathway and its applications to various diseases using Network based approach.

Richa Buddham, Sweety Chauhan, Priyanka Narad, Puniti Mathur.

  Mammalian target of rapamycin (mTOR) is a serine-threonine kinase member of the cellular phosphatidylinositol 3-kinase (PI3K) pathway, which is involved in multiple biological functions by transcriptional and translational control. mTOR is a downstream mediator in the PI3K/Akt signaling pathway and plays a critical role in cell survival. In cancer, this pathway can be activated by membrane receptors, including the HER (or ErbB) family of growth factor receptors, the insulin-like growth factor receptor, and the estrogen receptor. In the present work, we congregated an electronic network of mTORC1 built on an assembly of data using NLP, consisting of 470 edges (activations/interactions and/or inhibitions) and 206 nodes representing genes/proteins, using the Cytoscape 3.6.0 editor and its plugins for analysis. The experimental design included the extraction of gene expression data of five distinct type of cancers namely, pancreatic ductal adenocarcinoma, hepatic cirrhosis, cervical cancer, glioblastoma and Anaplastic thyroid cancer from Gene Expression Omnibus (NCBI GEO) and performing its pre-processing and normalization using R & Bioconductor. ExprEssence plugin was used for network condensation to identify differentially expressed genes across the gene expression samples. Gene Ontology (GO) analysis was performed to find out the over-represented GO terms in the network. Pathway enrichment as well as functional module analysis of the protein-protein interaction (PPI) network was carried out. Our results indicated NOTCH1, NOTCH3, FLCN, SOD1, SOD2, NF1, and TLR4 as upregulated proteins in different cancer types highlighting their role in cancer progression. The MCODE analysis identified gene clusters for each cancer type with MYC, PCNA, PARP1, IDH1, FGF10, PTEN, and CCND1 as hub genes with high connectivity. MYC for cervical cancer, IDH1 for hepatic cirrhosis, MGMT for glioblastoma and CCND1 for anaplastic thyroid cancer were identified as genes with prognostic importance using survival analysis.

Keywords:  differentially expressed genes; gene and pathway enrichment; mTORC1 Network; survival analysis

DOI:  https://doi.org/10.4014/jmb.2108.08007
JCI Insight. 2022 Jan 11. pii: e153688. [Epub ahead of print]7(1):

Targeting the undruggable oncogenic KRAS: the dawn of hope.

Hande Asimgil, Utku Ertetik, Nedim Can Çevik, Menar Ekizce, Alper Doğruöz, Muazzez Gökalp, Elif Arık-Sever, Rouzanna Istvanffy, Helmut Friess, Güralp Onur Ceyhan, Ihsan Ekin Demir.

KRAS mutations are the drivers of various cancers, including non-small cell lung cancer, colon cancer, and pancreatic cancer. Over the last 30 years, immense efforts have been made to inhibit KRAS mutants and oncogenic KRAS signaling using inhibitors. Recently, specific targeting of KRAS mutants with small molecules revived the hopes for successful therapies for lung, pancreatic, and colorectal cancer patients. Moreover, advances in gene editing, protein engineering, and drug delivery formulations have revolutionized cancer therapy regimens. New therapies aim to improve immune surveillance and enhance antitumor immunity by precisely targeting cancer cells harboring oncogenic KRAS. Here, we review recent KRAS-targeting strategies, their therapeutic potential, and remaining challenges to overcome. We also highlight the potential synergistic effects of various combinatorial therapies in preclinical and clinical trials.

DOI: https://doi.org/10.1172/jci.insight.153688
Mol Biol Cell. 2022 Jan 12. mbcE21060309

PP2A-dependent TFEB activation is blocked by PIKfyve-induced mTORC1 activity.

Junya Hasegawa, Emi Tokuda, Yao Yao, Takehiko Sasaki, Ken Inoki, Lois S Weisman.

Transcriptional factor EB (TFEB) is a master regulator of genes required for autophagy and lysosomal function. The nuclear localization of TFEB is blocked by the mechanistic target of rapamycin complex 1 (mTORC1)-dependent phosphorylation of TFEB at multiple sites including Ser-211. Here we show that inhibition of PIKfyve, which produces phosphatidylinositol 3,5-bisphosphate on endosomes and lysosomes, causes a loss of Ser-211 phosphorylation and concomitant nuclear localization of TFEB. We found that while mTORC1 activity toward S6K1, as well as other major mTORC1 substrates, is not impaired, PIKfyve inhibition specifically impedes the interaction of TFEB with mTORC1. This suggests that mTORC1 activity on TFEB is selectively inhibited due to loss of mTORC1 access to TFEB. In addition, we found that TFEB activation during inhibition of PIKfyve relies on the ability of protein phosphatase 2A (PP2A) but not calcineurin/PPP3, to dephosphorylate TFEB Ser-211. Thus, when PIKfyve is inhibited, PP2A is dominant over mTORC1 for control of TFEB phosphorylation at Ser-S211. Together these findings suggest that mTORC1 and PP2A have opposing roles on TFEB via phosphorylation and dephosphorylation of Ser-211, respectively, and further, that PIKfyve inhibits TFEB activity by facilitating mTORC1-dependent phosphorylation of TFEB.

DOI: https://doi.org/10.1091/mbc.E21-06-0309
Cancers (Basel). 2022 Jan 05. pii: 252. [Epub ahead of print]14(1):

Upregulation of CD36, a Fatty Acid Translocase, Promotes Colorectal Cancer Metastasis by Increasing MMP28 and Decreasing E-Cadherin Expression.

James Drury, Piotr G Rychahou, Courtney O Kelson, Mariah E Geisen, Yuanyuan Wu, Daheng He, Chi Wang, Eun Y Lee, B Mark Evers, Yekaterina Y Zaytseva.

  Altered fatty acid metabolism continues to be an attractive target for therapeutic intervention in cancer. We previously found that colorectal cancer (CRC) cells with a higher metastatic potential express a higher level of fatty acid translocase (CD36). However, the role of CD36 in CRC metastasis has not been studied. Here, we demonstrate that high expression of CD36 promotes invasion of CRC cells. Consistently, CD36 promoted lung metastasis in the tail vein model and GI metastasis in the cecum injection model. RNA-Seq analysis of CRC cells with altered expression of CD36 revealed an association between high expression of CD36 and upregulation of MMP28, a novel member of the metallopeptidase family of proteins. Using shRNA-mediated knockdown and overexpression of CD36, we confirmed that CD36 regulates MMP28 expression in CRC cells. siRNA-mediated knockdown of MMP28 decreases invasion of CRC cells, suggesting that MMP28 regulates the metastatic properties of cells downstream of CD36. Importantly, high expression of MMP28 leads to a significant decrease in active E-cadherin and an increase in the products of E-cadherin cleavage, CTF1 and CTF2. In summary, upregulation of CD36 expression promotes the metastatic properties of CRC via upregulation of MMP28 and an increase in E-cadherin cleavage, suggesting that targeting the CD36-MMP28 axis may be an effective therapeutic strategy for CRC metastasis.

Keywords:  CD36; E-cadherin; MMP28; colorectal cancer; fatty-acid metabolism; metastasis

DOI:  https://doi.org/10.3390/cancers14010252
Eur J Med Chem. 2022 Jan 03. pii: S0223-5234(21)00937-5. [Epub ahead of print]230 114088

Efficient targeted oncogenic KRASG12C degradation via first reversible-covalent PROTAC.

Fang Yang, Yalei Wen, Chaofan Wang, Yuee Zhou, Yang Zhou, Zhi-Min Zhang, Tongzheng Liu, Xiaoyun Lu.

  KRAS is the most frequently mutated oncogene and plays a predominant role in driving initiation and progression of multiple cancers. Attempts to degrade the oncogene KRASG12C with PROTAC strategy have been considered as an alternative strategy to combate cancers. However, the irreversible PROTACs may compromise the substoichiometric activity to decrease the potency. Herein, we report the development of YF135, the first reversible-covalent PROTAC capable of recruiting VHL mediated proteasomal degradation of KRASG12C. YF135 induces the rapid and sustained degradation of endogenous KRASG12C and attenuates pERK signaling in H358 and H23 cells in a reversible manner.

Keywords:  Anticancer; KRAS(G12C); PROTAC; Reversible-covalent inhibitors; Warheads

DOI:  https://doi.org/10.1016/j.ejmech.2021.114088
Nutrients. 2021 Dec 21. pii: 16. [Epub ahead of print]14(1):

The Timing and Duration of Folate Restriction Differentially Impacts Colon Carcinogenesis.

Ali M Fardous, Safa Beydoun, Andrew A James, Hongzhi Ma, Diane C Cabelof, Archana Unnikrishnan, Ahmad R Heydari.

  Diet plays a crucial role in the development of colorectal cancer (CRC). Of particular importance, folate, present in foods and supplements, is a crucial modulator of CRC risk. The role of folate, and, specifically, the synthetic variant, folic acid, in the primary prevention of CRC has not been fully elucidated. Animal studies varied considerably in the timing, duration, and supplementation of folates, leading to equivocal results. Our work attempts to isolate these variables to ascertain the role of folic acid in CRC initiation, as we previously demonstrated that folate restriction conferred protection against CRC initiation in a β-pol haploinsufficient mouse model. Here we demonstrated that prior adaptation to folate restriction altered the response to carcinogen exposure in wild-type C57BL/6 mice. Mice adapted to folate restriction for 8 weeks were protected from CRC initiation compared to mice placed on folate restriction for 1 week, irrespective of antibiotic supplementation. Through analyses of mTOR signaling, DNA methyltransferase, and DNA repair, we have identified factors that may play a critical role in the differential responses to folate restriction. Furthermore, the timing and duration of folate restriction altered these pathways differently in the absence of carcinogenic insult. These results represent novel findings, as we were able to show that, in the same model and under controlled conditions, folate restriction produced contrasting results depending on the timing and duration of the intervention.

Keywords:  C57bl/6; CRC; cancer; colon; depletion; folate; folic acid; mTOR; mice; restriction

DOI:  https://doi.org/10.3390/nu14010016
Cell Commun Signal. 2022 Jan 08. 20(1): 5

GqPCR-stimulated dephosphorylation of AKT is induced by an IGBP1-mediated PP2A switch.

Guy Nadel, Zhong Yao, Ehud Wainstein, Izel Cohen, Ido Ben-Ami, Amir Schajnovitz, Galia Maik-Rachline, Zvi Naor, Benjamin A Horwitz, Rony Seger.

  BACKGROUND: G protein-coupled receptors (GPCRs) usually regulate cellular processes via activation of intracellular signaling pathways. However, we have previously shown that in several cell lines, GqPCRs induce immediate inactivation of the AKT pathway, which leads to JNK-dependent apoptosis. This apoptosis-inducing AKT inactivation is essential for physiological functions of several GqPCRs, including those for PGF2α and GnRH.METHODS: Here we used kinase activity assays of PI3K and followed phosphorylation state of proteins using specific antibodies. In addition, we used coimmunoprecipitation and proximity ligation assays to follow protein-protein interactions. Apoptosis was detected by TUNEL assay and PARP1 cleavage.
RESULTS: We identified the mechanism that allows the unique stimulated inactivation of AKT and show that the main regulator of this process is the phosphatase PP2A, operating with the non-canonical regulatory subunit IGBP1. In resting cells, an IGBP1-PP2Ac dimer binds to PI3K, dephosphorylates the inhibitory pSer608-p85 of PI3K and thus maintains its high basal activity. Upon GqPCR activation, the PP2Ac-IGBP1 dimer detaches from PI3K and thus allows the inhibitory dephosphorylation. At this stage, the free PP2Ac together with IGBP1 and PP2Aa binds to AKT, causing its dephosphorylation and inactivation.
CONCLUSION: Our results show a stimulated shift of PP2Ac from PI3K to AKT termed "PP2A switch" that represses the PI3K/AKT pathway, providing a unique mechanism of GPCR-stimulated dephosphorylation. Video Abstract.

Keywords:  AKT; IGBP1; PI3K; PKC; PP2A

DOI:  https://doi.org/10.1186/s12964-021-00805-z