bims-pimaco 2022-10-02 papers

on PI3K and MAPK signalling in colorectal cancer

Issue of 2022–10–02
nineteen papers selected by
Lucas B. Zeiger, CRUK Scotland Institute, Beatson Institute for Cancer Research

The role of RAS oncogenes in controlling epithelial mechanics.
Structure of the SHOC2-MRAS-PP1C complex provides insights into RAF activation and Noonan syndrome.
SFPQ promotes RAS-mutant cancer cell growth by modulating 5'-UTR mediated translational control of CK1α.
Targeting GRP78 suppresses oncogenic KRAS protein expression and reduces viability of cancer cells bearing various KRAS mutations.
Correlation between KRAS, NRAS and BRAF mutations and tumor localizations in patients with primary and metastatic colorectal cancer.
Raptor knockdown concurrently increases the electrical resistance and paracellular permeability of Caco-2 cell monolayers.
Loss of the Fbw7 tumor suppressor rewires cholesterol metabolism in cancer cells leading to activation of the PI3K-AKT signalling axis.
Energy balance-related factors in childhood and adolescence and risk of colorectal cancer based on KRAS, PIK3CA, and BRAF mutations and MMR status.
Base excision repair accessory factors in senescence avoidance and resistance to treatments.
NanoSIMS imaging of fatty acid and cholesterol absorption by intestinal enterocytes.
Both phosphorylation and phosphatase activity of PTEN are required to prevent replication fork progression during stress by inducing heterochromatin.
Small-Molecule Modulators Targeting SHP2 for Cancer Therapy.
Akt: a key transducer in cancer.
Cholesterol promotes clustering of PI(4,5)P2 driving unconventional secretion of FGF2.
ERK signaling dynamics: Lights, camera, transduction.
Comprehensive proteomic signature and identification of CDKN2A as a promising prognostic biomarker and therapeutic target of colorectal cancer.
Targeting p85β nuclear translocation for the tumors with PIK3CA helical domain mutations.
High expression of phosphorylated focal adhesion kinase predicts a poor prognosis in human colorectal cancer.
Kinetic Changes of Ptdins (3,4,5) P3 within Fast and Slow Turnover Rates of Focal Adhesion.

Trends Cell Biol. 2022 Sep 26. pii: S0962-8924(22)00212-4. [Epub ahead of print]

The role of RAS oncogenes in controlling epithelial mechanics.

Agata Nyga, Sushila Ganguli, Helen K Matthews, Buzz Baum.

  Mutations in RAS are key oncogenic drivers and therapeutic targets. Oncogenic Ras proteins activate a network of downstream signalling pathways, including extracellular signal-regulated kinase (ERK) and phosphatidylinositol 3-kinase (PI3K), promoting cell proliferation and survival. However, there is increasing evidence that RAS oncogenes also alter the mechanical properties of both individual malignant cells and transformed tissues. Here we discuss the role of oncogenic RAS in controlling mechanical cell phenotypes and how these mechanical changes promote oncogenic transformation in single cells and tissues. RAS activation alters actin organisation and actomyosin contractility. These changes alter cell rheology and impact mechanosensing through changes in substrate adhesion and YAP/TAZ-dependent mechanotransduction. We then discuss how these changes play out in cell collectives and epithelial tissues by driving large-scale tissue deformations and the expansion of malignant cells. Uncovering how RAS oncogenes alter cell mechanics will lead to a better understanding of the morphogenetic processes that underlie tumour formation in RAS-mutant cancers.

Keywords:  RAS; YAP/TAZ signalling; actin; epithelia; mechanobiology; mechanotransduction; myosin; oncogene; tissue mechanics

DOI:  https://doi.org/10.1016/j.tcb.2022.09.002
Nat Struct Mol Biol. 2022 Sep 29.

Structure of the SHOC2-MRAS-PP1C complex provides insights into RAF activation and Noonan syndrome.

Daniel A Bonsor, Patrick Alexander, Kelly Snead, Nicole Hartig, Matthew Drew, Simon Messing, Lorenzo I Finci, Dwight V Nissley, Frank McCormick, Dominic Esposito, Pablo Rodriguez-Viciana, Andrew G Stephen, Dhirendra K Simanshu.

SHOC2 acts as a strong synthetic lethal interactor with MEK inhibitors in multiple KRAS cancer cell lines. SHOC2 forms a heterotrimeric complex with MRAS and PP1C that is essential for regulating RAF and MAPK-pathway activation by dephosphorylating a specific phosphoserine on RAF kinases. Here we present the high-resolution crystal structure of the SHOC2-MRAS-PP1C (SMP) complex and apo-SHOC2. Our structures reveal that SHOC2, MRAS, and PP1C form a stable ternary complex in which all three proteins synergistically interact with each other. Our results show that dephosphorylation of RAF substrates by PP1C is enhanced upon interacting with SHOC2 and MRAS. The SMP complex forms only when MRAS is in an active state and is dependent on SHOC2 functioning as a scaffolding protein in the complex by bringing PP1C and MRAS together. Our results provide structural insights into the role of the SMP complex in RAF activation and how mutations found in Noonan syndrome enhance complex formation, and reveal new avenues for therapeutic interventions.

DOI: https://doi.org/10.1038/s41594-022-00841-4
NAR Cancer. 2022 Sep;4(3): zcac027

SFPQ promotes RAS-mutant cancer cell growth by modulating 5'-UTR mediated translational control of CK1α.

Venetia Jing Tong Kok, Jia Ying Tang, Gracie Wee Ling Eng, Shin Yi Tan, Joseph Tin Foong Chin, Chun Hian Quek, Wei Xuan Lai, Teck Kwang Lim, Qingsong Lin, John Jia En Chua, Jit Kong Cheong.

Oncogenic mutations in the RAS family of small GTPases are commonly found in human cancers and they promote tumorigenesis by altering gene expression networks. We previously demonstrated that Casein Kinase 1α (CK1α), a member of the CK1 family of serine/threonine kinases, is post-transcriptionally upregulated by oncogenic RAS signaling. Here, we report that the CK1α mRNA contains an exceptionally long 5'-untranslated region (UTR) harbouring several translational control elements, implicating its involvement in translational regulation. We demonstrate that the CK1α 5'-UTR functions as an IRES element in HCT-116 colon cancer cells to promote cap-independent translation. Using tobramycin-affinity RNA-pulldown assays coupled with identification via mass spectrometry, we identified several CK1α 5'-UTR-binding proteins, including SFPQ. We show that RNA interference targeting SFPQ reduced CK1α protein abundance and partially blocked RAS-mutant colon cancer cell growth. Importantly, transcript and protein levels of SFPQ and other CK1α 5'-UTR-associated RNA-binding proteins (RBPs) are found to be elevated in early stages of RAS-mutant cancers, including colorectal and lung adenocarcinoma. Taken together, our study uncovers a previously unappreciated role of RBPs in promoting RAS-mutant cancer cell growth and their potential to serve as promising biomarkers as well as tractable therapeutic targets in cancers driven by oncogenic RAS.

DOI: https://doi.org/10.1093/narcan/zcac027
Neoplasia. 2022 Nov;pii: S1476-5586(22)00063-X. [Epub ahead of print]33 100837

Targeting GRP78 suppresses oncogenic KRAS protein expression and reduces viability of cancer cells bearing various KRAS mutations.

Dat P Ha, Bo Huang, Han Wang, Daisy Flores Rangel, Richard Van Krieken, Ze Liu, Soma Samanta, Nouri Neamati, Amy S Lee.

  KRAS is the most commonly mutated oncogene in human cancers with limited therapeutic options, thus there is a critical need to identify novel targets and inhibiting agents. The 78-kDa glucose-regulated protein GRP78, which is upregulated in KRAS cancers, is an essential chaperone and the master regulator of the unfolded protein response (UPR). Following up on our recent discoveries that GRP78 haploinsufficiency suppresses both KRASG12D-driven pancreatic and lung tumorigenesis, we seek to determine the underlying mechanisms. Here, we report that knockdown of GRP78 via siRNA reduced oncogenic KRAS protein level in human lung, colon, and pancreatic cancer cells bearing various KRAS mutations. This effect was at the post-transcriptional level and is independent of proteasomal degradation or autophagy. Moreover, targeting GRP78 via small molecule inhibitors such as HA15 and YUM70 with anti-cancer activities while sparing normal cells significantly suppressed oncogenic KRAS expression in vitro and in vivo, associating with onset of apoptosis and loss of viability in cancer cells bearing various KRAS mutations. Collectively, our studies reveal that GRP78 is a previously unidentified regulator of oncogenic KRAS expression, and, as such, augments the other anti-cancer activities of GRP78 small molecule inhibitors to potentially achieve general, long-term suppression of mutant KRAS-driven tumorigenesis.

Keywords:  Colon cancer; GRP78; KRAS; Lung cancer; Pancreatic cancer; Small molecule inhibitors

DOI:  https://doi.org/10.1016/j.neo.2022.100837
Arch Med Sci. 2022 ;18(5): 1221-1230

Correlation between KRAS, NRAS and BRAF mutations and tumor localizations in patients with primary and metastatic colorectal cancer.

Aleksandra Bożyk, Paweł Krawczyk, Katarzyna Reszka, Kinga Krukowska, Agnieszka Kolak, Sławomir Mańdziuk, Kamila Wojas-Krawczyk, Rodryg Ramlau, Janusz Milanowski.

   Introduction: Detection of abnormalities in the KRAS, NRAS and BRAF genes is extremely important for proper qualification of colorectal cancer (CRC) patients for therapy with anti-EGFR (epidermal growth factor receptor) monoclonal antibodies. However, data about prevalence of mutations in these genes, in different localizations of CRC tumors, are limited.
Material and methods: We examined the frequency of mutations in the KRAS, NRAS and BRAF genes in 500 Caucasian CRC patients (200 women and 300 men, median age 66 years). DNA was isolated from formalin-fixed, paraffin-embedded (FFPE) tissues using a Qiagen QIAamp DNA FFPE-kit. Analysis of mutations was carried out using the KRAS/BRAF, NRAS and BRAF Mutation Analysis Kit for Real-Time PCR (EntroGen) with the Cobas 480 real-time PCR apparatus (Roche Diagnostics).
Results: KRAS mutations were detected in 190 (38%) patients, NRAS mutations in 20 (4%) patients, and BRAF mutations in 24 (4.8%) patients. There were no associations between age of CRC patients and frequency of KRAS, NRAS and BRAF gene mutations. These mutations were significantly more often diagnosed in women (55.5%) than in men (41%, p < 0.005). Tumors of the rectum and sigmoideum were the most often observed in both groups of CRC patients - with and without KRAS, NRAS and BRAF gene mutations. However, transverse colon, ascending colon and cecum cancers were the most often affected by mutations.
Conclusions: Our study showed that the occurrence of mutations in the KRAS, NRAS and BRAF genes is not accidental and depends on the location of CRC tumors.

Keywords:  BRAF; KRAS; NRAS; colorectal cancer

DOI:  https://doi.org/10.5114/aoms/109170
Life Sci. 2022 Sep 21. pii: S0024-3205(22)00689-0. [Epub ahead of print]308 120989

Raptor knockdown concurrently increases the electrical resistance and paracellular permeability of Caco-2 cell monolayers.

Harleen Kaur, Régis Moreau.

   AIMS: As a critical regulatory point of nutrient sensing, growth and metabolism, the mechanistic target of rapamycin complex 1 (mTORC1) is poised to influence intestinal homeostasis under basal conditions and in disease state. Intestinal barrier integrity ensures tissue homeostasis by closely regulating the permeability of the epithelium to lumenal contents. The role of mTORC1 in the regulation of intestinal barrier function and permeability remains to be fully elucidated.
MATERIALS AND METHODS: In this study, we employed lentivirus-mediated knockdown of mTORC1 signaling-associated proteins Raptor (regulatory-associated protein of mTOR) and TSC2 (tuberin) to ascertain the effects of constitutive activation or repression of mTORC1 activity on barrier function in Caco-2 cell monolayers.
KEY FINDINGS: Results showed that the loss of Raptor concomitantly raised the transepithelial electrical resistance (TEER) and para/transcellular permeability leading to a cell monolayer that is leaky for dextran yet electrically resistant to the movement of ions. Paracellular permeability was linked to the downregulation of tight junction protein expression and enhanced autophagy. Raptor-depleted cells had the highest abundance of myosin binding subunit MYPT1 concomitantly with the lowest abundance of p-MYPT1 (Thr696) and phosphorylated myosin light chain (p-MLC, Ser19) implying that MLC phosphatase activity was increased resulting in MLC relaxation. Although rapamycin suppressed mTORC1 activity and decreased the abundance of tight junction proteins in control cells, rapamycin caused a modest increase of TEER compared to Raptor knockdown.
SIGNIFICANCE: The study showed that epithelium paracellular permeability of small molecular weight dextran is dissociated from TEER.

Keywords:  Autophagy; Claudin; Intestinal epithelium; Rapamycin; Tight junction; mTORC1

DOI:  https://doi.org/10.1016/j.lfs.2022.120989
Front Oncol. 2022 ;12 990672

Loss of the Fbw7 tumor suppressor rewires cholesterol metabolism in cancer cells leading to activation of the PI3K-AKT signalling axis.

Maria T Bengoechea-Alonso, Arwa Aldaalis, Johan Ericsson.

  The sterol regulatory-element binding proteins (SREBPs) are transcription factors controlling cholesterol and fatty acid synthesis and metabolism. There are three SREBP proteins, SREBP1a, SREBP1c and SREBP2, with SREBP1a being the strongest transcription factor. The expression of SREBP1a is restricted to rapidly proliferating cells, including cancer cells. The SREBP proteins are translated as large, inactive precursors bound to the endoplasmic reticulum (ER) membranes. These precursors undergo a two-step cleavage process that releases the amino terminal domains of the proteins, which translocate to the nucleus and function as transcription factors. The nuclear forms of the SREBPs are rapidly degraded by the ubiquitin-proteasome system in a manner dependent on the Fbw7 ubiquitin ligase. Consequently, inactivation of Fbw7 results in the stabilization of active SREBP1 and SREBP2 and enhanced expression of target genes. We report that the inactivation of Fbw7 in cancer cells blocks the proteolytic maturation of SREBP2. The same is true in cells expressing a cancer-specific loss-of-function Fbw7 protein. Interestingly, the activation of SREBP2 is restored in response to cholesterol depletion, suggesting that Fbw7-deficient cells accumulate cholesterol. Importantly, inactivation of SREBP1 in Fbw7-deficient cells also restores the cholesterol-dependent regulation of SREBP2, suggesting that the stabilization of active SREBP1 molecules could be responsible for the blunted activation of SREBP2 in Fbw7-deficient cancer cells. We suggest that this could be an important negative feedback loop in cancer cells with Fbw7 loss-of-function mutations to protect these cells from the accumulation of toxic levels of cholesterol and/or cholesterol metabolites. Surprisingly, we also found that the inactivation of Fbw7 resulted in the activation of AKT. Importantly, the activation of AKT was dependent on SREBP1 and on the accumulation of cholesterol. Thus, we suggest that the loss of Fbw7 rewires lipid metabolism in cancer cells to support cell proliferation and survival.

Keywords:  AKT; Fbw7; PI3K; SREBP; cancer; cholesterol

DOI:  https://doi.org/10.3389/fonc.2022.990672
Mol Carcinog. 2022 Sep 30.

Energy balance-related factors in childhood and adolescence and risk of colorectal cancer based on KRAS, PIK3CA, and BRAF mutations and MMR status.

Josien C A Jenniskens, Kelly Offermans, Colinda C J M Simons, Iryna Samarska, Gregorio E Fazzi, Jaleesa R M van der Meer, Kim M Smits, Leo J Schouten, Matty P Weijenberg, Heike I Grabsch, Piet A van den Brandt.

  KRAS mutations (KRASmut ), PIK3CAmut , BRAFmut , and deficient DNA mismatch repair (dMMR) have been associated with the Warburg effect. We previously reported differential associations between early-life energy balance-related factors (height, energy restriction, body mass index [BMI]) and colorectal cancer (CRC) subtypes based on the Warburg effect. We now investigated associations of early-life energy balance-related factors and the risk of CRC subgroups based on mutation and MMR status. Data from the Netherlands Cohort Study was used. KRASmut , PIK3CAmut, BRAFmut, and MMR status were available for 2349 CRC cases, and complete covariate data for 1934 cases and 3911 subcohort members. Multivariable-adjusted Cox regression was used to estimate associations of height, energy restriction proxies (exposure to Dutch Hunger Winter, Second World War, Economic Depression), and early adult BMI (age 20 years) with risk of CRC based on individual molecular features and combinations thereof (all-wild-type+MMR-proficient [pMMR]; any-mutation/dMMR). Height was positively associated with any-mutation/dMMR CRC but not all-wild-type+pMMR CRC, with the exception of rectal cancer in men, and with heterogeneity in associations observed for colon cancer in men (p-heterogeneity = 0.049) and rectal cancer in women (p-heterogeneity = 0.014). Results on early-life energy restriction proxies in relation to the risk of CRC subgroups did not show clear patterns. Early adult BMI was positively, but not significantly, associated with KRASmut colon cancer in men and with BRAFmut and dMMR colon cancer in women. Our results suggest a role of KRASmut , PIK3CAmut , BRAFmut , and dMMR in the etiological pathway between height and CRC risk. KRASmut might potentially play a role in associations of early adult BMI with colon cancer risk in men, and BRAFmut and dMMR in women.

Keywords:  colorectal cancer; early-life energy balance; mismatch repair/microsatellite instability; mutations; prospective cohort study

DOI:  https://doi.org/10.1002/mc.23459
Cancer Drug Resist. 2022 ;5(3): 703-720

Base excision repair accessory factors in senescence avoidance and resistance to treatments.

Elise Vickridge, Camila C F Faraco, Alain Nepveu.

  Cancer cells, in which the RAS and PI3K pathways are activated, produce high levels of reactive oxygen species (ROS), which cause oxidative DNA damage and ultimately cellular senescence. This process has been documented in tissue culture, mouse models, and human pre-cancerous lesions. In this context, cellular senescence functions as a tumour suppressor mechanism. Some rare cancer cells, however, manage to adapt to avoid senescence and continue to proliferate. One well-documented mode of adaptation involves increased production of antioxidants often associated with inactivation of the KEAP1 tumour suppressor gene and the resulting upregulation of the NRF2 transcription factor. In this review, we detail an alternative mode of adaptation to oxidative DNA damage induced by ROS: the increased activity of the base excision repair (BER) pathway, achieved through the enhanced expression of BER enzymes and DNA repair accessory factors. These proteins, exemplified here by the CUT domain proteins CUX1, CUX2, and SATB1, stimulate the activity of BER enzymes. The ensued accelerated repair of oxidative DNA damage enables cancer cells to avoid senescence despite high ROS levels. As a by-product of this adaptation, these cancer cells exhibit increased resistance to genotoxic treatments including ionizing radiation, temozolomide, and cisplatin. Moreover, considering the intrinsic error rate associated with DNA repair and translesion synthesis, the elevated number of oxidative DNA lesions caused by high ROS leads to the accumulation of mutations in the cancer cell population, thereby contributing to tumour heterogeneity and eventually to the acquisition of resistance, a major obstacle to clinical treatment.

Keywords:  Base excision repair; reactive oxygen species, DNA repair accessory factor, oxidative DNA damage, resistance to treatment, tumour heterogeneity, acquisition of resistance

DOI:  https://doi.org/10.20517/cdr.2022.36
J Lipid Res. 2022 Sep 27. pii: S0022-2275(22)00123-7. [Epub ahead of print] 100290

NanoSIMS imaging of fatty acid and cholesterol absorption by intestinal enterocytes.

Kai Chen, Wenxin Song, Robert Russell, Alessandra Ferrari, Tamim Darwish, Peter Tontonoz, Stephen G Young, Haibo Jiang.

DOI: https://doi.org/10.1016/j.jlr.2022.100290
Mutat Res. 2022 Sep 19. pii: S0027-5107(22)00027-6. [Epub ahead of print]825 111800

Both phosphorylation and phosphatase activity of PTEN are required to prevent replication fork progression during stress by inducing heterochromatin.

Sandip Misra, Sougata Ghosh Chowdhury, Ginia Ghosh, Ananda Mukherjee, Parimal Karmakar.

  PTEN is a tumor suppressor protein frequently altered in various cancers. PTEN-null cells have a characteristic of rapid proliferation with an unstable genome. Replication stress is one of the causes of the accumulation of genomic instability if not sensed by the cellular signaling. Though PTEN-null cells have shown to be impaired in replication progression and stalled fork recovery, the association between the catalytic function of PTEN regulated by posttranslational modulation and cellular response to replication stress has not been studied explicitly. To understand molecular mechanism, we find that PTEN-null cells display unrestrained replication fork progression with accumulation of damaged DNA after treatment with aphidicolin which can be rescued by ectopic expression of full-length PTEN, as evident from DNA fiber assay. Moreover, the C-terminal phosphorylation (Ser 380, Thr 382/383) of PTEN is essential for its chromatin association and sensing replication stress that, in response, induce cell cycle arrest. Further, we observed that PTEN induces HP1α expression and H3K9me3 foci formation in a C-terminal phosphorylation-dependent manner. However, phosphatase dead PTEN cannot sense replication stress though it can be associated with chromatin. Together, our results suggest that DNA replication perturbation by aphidicolin enables chromatin association of PTEN through C-terminal phosphorylation, induces heterochromatin formation by stabilizing and up-regulating H3K9me3 foci and augments CHK1 activation. Thereby, PTEN prevents DNA replication fork elongation and simultaneously causes G1-S phase cell cycle arrest to limit cell proliferation in stress conditions. Thus PTEN act as stress sensing protein during replication arrest to maintain genomic stability.

Keywords:  Heterochromatin; PTEN; Phosphatase activity; Phosphorylation; Replication

DOI:  https://doi.org/10.1016/j.mrfmmm.2022.111800
Anticancer Agents Med Chem. 2022 Sep 21.

Small-Molecule Modulators Targeting SHP2 for Cancer Therapy.

Dazhao Mi, Yuzhan Li, Yihua Chen.

   BACKGROUND: SHP2 is a protein tyrosine phosphatase that is extensively involved in several signaling pathways related to cancer occurrence, and thus SHP2 has been proposed an attractive target for cancer treatment.
METHODS: After a brief introduction of SHP2, we provided a short overview of the structure, function and regulation mechanism of SHP2 in cancer occurrence. Then, this perspective focused on the current therapeutic strategies targeting SHP2, including SHP2 PTP inhibitors, SHP2 allosteric inhibitors and SHP2-targeting PROTACs, and discussed the benefits and defects of these strategies. Finally, the opportunities and challenges were presented.
RESULTS: SHP2 regulated RAS-ERK, PI3K-AKT, JAK-STAT and PD-1/PD-L1 signaling pathways involved in pathogenesis of cancer via conformations conversion. Current therapeutic strategies targeting SHP2, especially SHP2 allosteric inhibitors, hold significant potency and have broad application prospects for cancer therapy.
CONCLUSION: In summary, SHP2 is a promising therapeutic target and strategies targeting SHP2 offer an alternative program for cancer patients.

Keywords:  PROTACs.; SHP2; SHP2 PTP inhibitors; SHP2 allosteric inhibitors; cancer treatment; phosphatase

DOI:  https://doi.org/10.2174/1871520622666220921093052
J Biomed Sci. 2022 Oct 01. 29(1): 76

Akt: a key transducer in cancer.

Pei-Jane Tsai, Yi-Hsin Lai, Rajesh Kumar Manne, Yau-Sheng Tsai, Dos Sarbassov, Hui-Kuan Lin.

  Growth factor signaling plays a pivotal role in diverse biological functions, such as cell growth, apoptosis, senescence, and migration and its deregulation has been linked to various human diseases. Akt kinase is a central player transmitting extracellular clues to various cellular compartments, in turn executing these biological processes. Since the discovery of Akt three decades ago, the tremendous progress towards identifying its upstream regulators and downstream effectors and its roles in cancer has been made, offering novel paradigms and therapeutic strategies for targeting human diseases and cancers with deregulated Akt activation. Unraveling the molecular mechanisms for Akt signaling networks paves the way for developing selective inhibitors targeting Akt and its signaling regulation for the management of human diseases including cancer.

Keywords:  Akt; Cancer; PI3K; Posttranslational modifications; Skp2; TRAF6

DOI:  https://doi.org/10.1186/s12929-022-00860-9
J Cell Biol. 2022 Nov 07. pii: e202106123. [Epub ahead of print]221(11):

Cholesterol promotes clustering of PI(4,5)P2 driving unconventional secretion of FGF2.

Fabio Lolicato, Roberto Saleppico, Alessandra Griffo, Annalena Meyer, Federica Scollo, Bianca Pokrandt, Hans-Michael Müller, Helge Ewers, Hendrik Hähl, Jean-Baptiste Fleury, Ralf Seemann, Martin Hof, Britta Brügger, Karin Jacobs, Ilpo Vattulainen, Walter Nickel.

FGF2 is a cell survival factor involved in tumor-induced angiogenesis that is secreted through an unconventional secretory pathway based upon direct protein translocation across the plasma membrane. Here, we demonstrate that both PI(4,5)P2-dependent FGF2 recruitment at the inner plasma membrane leaflet and FGF2 membrane translocation into the extracellular space are positively modulated by cholesterol in living cells. We further revealed cholesterol to enhance FGF2 binding to PI(4,5)P2-containing lipid bilayers. Based on extensive atomistic molecular dynamics (MD) simulations and membrane tension experiments, we proposed cholesterol to modulate FGF2 binding to PI(4,5)P2 by (i) increasing head group visibility of PI(4,5)P2 on the membrane surface, (ii) increasing avidity by cholesterol-induced clustering of PI(4,5)P2 molecules triggering FGF2 oligomerization, and (iii) increasing membrane tension facilitating the formation of lipidic membrane pores. Our findings have general implications for phosphoinositide-dependent protein recruitment to membranes and explain the highly selective targeting of FGF2 toward the plasma membrane, the subcellular site of FGF2 membrane translocation during unconventional secretion of FGF2.

DOI: https://doi.org/10.1083/jcb.202106123
Dev Cell. 2022 Sep 26. pii: S1534-5807(22)00631-1. [Epub ahead of print]57(18): 2151-2152

ERK signaling dynamics: Lights, camera, transduction.

Abhineet Ram, John G Albeck.

Three-dimensional mammary epithelial acini are a model for understanding how microenvironment-driven signaling coordinates cell behavior and tissue morphogenesis. In this issue of Developmental Cell, Ender et al. use live-cell imaging to capture dynamic spatiotemporal patterns of ERK activity that instruct cell migration and survival fates in developing acini.

DOI: https://doi.org/10.1016/j.devcel.2022.09.001
World J Clin Cases. 2022 Aug 06. 10(22): 7686-7697

Comprehensive proteomic signature and identification of CDKN2A as a promising prognostic biomarker and therapeutic target of colorectal cancer.

Qian-Qian Wang, Yuan-Chen Zhou, Yu-Jia Zhou Ge, Geng Qin, Teng-Fei Yin, Dong-Yan Zhao, Chang Tan, Shu-Kun Yao.

   BACKGROUND: The carcinogenesis of colorectal cancer (CRC) involves many different molecules and multiple pathways, and the specific mechanism has not been elucidated until now. Existing studies on the proteomic signature profiles of CRC are relatively limited. Therefore, we herein aimed to provide a more comprehensive proteomic signature profile and discover new prognostic markers and therapeutic targets by performing proteomic analysis of CRC and paired normal tissues.
AIM: To investigate the proteomic signature and identify novel protein prognostic biomarkers of CRC.
METHODS: Cancer tissues and paired normal tissues were collected from 48 patients who underwent surgical removal at the China-Japan Friendship Hospital from January 2020 to June 2021. Data independent acquisition (DIA) quantitative proteomic analysis was performed using high-performance liquid chromatography-mass spectrometry/mass spectrometry (nano-UHPLC-MS/MS) to identify differentially expressed proteins, among which those with a P adj value (t test, BH correction) < 0.05 and an absolute fold change (|log2FC|) > 2 were identified as potential markers. Differentially expressed proteins were selected by bioinformatics analysis and validated by immunohistochemical tissue microarrays, and their association with prognosis was further analyzed with the Gene Expression Profiling Interactive Analysis database to identify prognostic protein biomarkers of CRC.
RESULTS: Significantly differential protein expression was observed between cancer tissues and normal tissues. Compared with normal tissues, 1115 proteins were upregulated and 705 proteins were downregulated in CRC based on P adj < 0.05 and |log2FC| > 2, and bioinformatics analysis revealed that the differentially expressed proteins were involved in multiple biological processes associated with tumorigenesis, including ribosome biogenesis in eukaryotes, focal adhesion, extracellular matrix-receptor interactions and other tumor metabolism processes. Moreover, cyclin-dependent kinase inhibitor 2A (CDKN2A) expression was markedly upregulated in CRC, as validated by immunohistochemistry (0.228 vs 0.364, P = 0.0044), and was significantly enriched in tumor proliferation and signal transduction pathways such as the cell cycle and p53 signaling pathways. High CDKN2A expression was significantly correlated with poor prognosis (P = 0.021). These results demonstrated that CDKN2A functions as a driver of CRC.
CONCLUSION: Our study provides a comprehensive proteomic signature of CRC and highlights CDKN2A as a potential powerful prognostic marker and precision therapeutic target.

Keywords:  Colorectal cancer; Cyclin-dependent kinase inhibitor 2A; Precision treatment; Prognostic biomarker; Proteomic analysis; Therapeutic target

DOI:  https://doi.org/10.12998/wjcc.v10.i22.7686
Genes Dis. 2022 Nov;9(6): 1391-1393

Targeting p85β nuclear translocation for the tumors with PIK3CA helical domain mutations.

Baoyu He, Yujun Hao.



Keywords:  EZH2; Helical domain mutation; PIK3CA; USP7; p85β

DOI:  https://doi.org/10.1016/j.gendis.2022.05.018
Front Pharmacol. 2022 ;13 989999

High expression of phosphorylated focal adhesion kinase predicts a poor prognosis in human colorectal cancer.

Guanyu Yu, Mengnan Xu, Leqi Zhou, Kuo Zheng, Xiaoming Zhu, Jinke Sui, Cheng Xin, Wenjun Chang, Wei Zhang, Fuao Cao.

  Background: Phosphorylated Focal adhesion kinase (FAK) has been reported to be intimately involved in various malignant tumors. The effect of p-FAK on colorectal cancer (CRC) is still disputable. The purpose of this study is to investigate the role of p-FAK in the prognosis of colorectal cancer. Methods: The clinical significance of p-FAK expression in CRC was evaluated by immunohistochemistry in a large cohort, including carcinoma and para-carcinoma tissues from 908 patients, and normal tissues, adenoma, and metastasis tissues. The correlation between p-FAK expression and CRC occurrence was investigated in tumor and other tissues. Factors contributing to prognosis were evaluated using Kaplan-Meier survival analysis and Cox regression model. Results: p-FAK is apparently overexpressed in CRC and metastasis tissues. Compared with low p-FAK expression, patients with high p-FAK expression had shorter overall survival [hazard ratio (HR), 2.200; 95% confidence interval (CI), 1.265-3.452; p < 0.01] and disease-free survival (HR, 2.004; 95% CI 1.262-3.382; p < 0.01) in multivariate Cox analysis after adjusting other prognostic factors. High p-FAK expression was also related to a worse chemotherapeutic response in patients who achieved adjuvant chemotherapy (p < 0.01). Conclusion: Expression level of p-FAK is an independent risk factor and can serve as a prognostic biomarker for CRC. High p-FAK expression predicts an unfavorable prognosis of CRC as well as poor chemotherapeutic response.

Keywords:  chemotherapy; colorectal cancer; immunohistochemistry; p-FAK; prognosis

DOI:  https://doi.org/10.3389/fphar.2022.989999
Rep Biochem Mol Biol. 2022 Jul;11(2): 262-269

Kinetic Changes of Ptdins (3,4,5) P3 within Fast and Slow Turnover Rates of Focal Adhesion.

Dhurgham Al-Fahad, Firas Alyaseen, Ahmed Al-Amery, Gagandeep Singh, Mote Srinath, Hafiz Muzzammel Rehman, Yahya Abbas.

   Background: The assembly and disassembly of the focal adhesions (FA) components occurs throughout life cycle of adhesion, with conservation of balance between removal and recruitment rate during temporal stages. Previous studies have demonstrated that phosphotidyilinositols play a role in regulating FA turnover. However, a little attention has been given to quantify the dynamics changes of Phosphatidylinositol 3,4,5-trisphosphate (PtdIns (3,4,5) P3) within and during fast and slow turnover rates of FA.
Methods: In this study, we developed a protein purification MDA-MB-231 breast cancer cell line was used as a model in this study due to high metastatic and motile. These cells were co-transfected with GFP- paxillin/vinculin, as FA marker, and the GFP/mCherry-Btk-PH, as a biosensor to visualize PtdIns (3,4,5) P3. Confocal time-lapse images were used to monitor changes or differences in the local generation of PtdIns (3,4,5) P3 within and during assembly and disassembly of FA. Following transfection, immunostaining was used to examine the spatial co-localization between FA and PtdIns (3,4,5) P3.
Results: Our data demonstrated that PtdIns (3,4,5) P3 co-localized with FAs and increase during assembly and decline during disassembly of FA which exhibits slow turnover rates and was in a constant level during assembly and disassembly of FA that displays fast turnover rates.
Discussion: Our result suggested that the dynamic changes of PtdIns (3,4,5) P3, it may depend on components undergo turnover, such that early, nascent FA displays fast turnover rates and mature FA exhibits slow turnover rates. Thus, the local enrichment of PtdIns (3,4,5) P3 enhances FA assembly and disassembly activation.

Keywords:  Cancer cell migration; Focal adhesion turnover; MDA-MB-231 cell line; PtdIns (3,4,5) P3

DOI:  https://doi.org/10.52547/rbmb.11.2.262