bims-pimaco Biomed News
on PI3K and MAPK signalling in colorectal cancer
Issue of 2020‒11‒22
sixteen papers selected by
Lucas B. Zeiger
Beatson Institute for Cancer Research


  1. Int J Mol Sci. 2020 Nov 13. pii: E8563. [Epub ahead of print]21(22):
    Götting I, Jendrossek V, Matschke J.
      Cancer resistance to chemotherapy, radiotherapy and molecular-targeted agents is a major obstacle to successful cancer therapy. Herein, aberrant activation of the phosphatidyl-inositol-3-kinase (PI3K)/protein kinase B (Akt) pathway is one of the most frequently deregulated pathways in cancer cells and has been associated with multiple aspects of therapy resistance. These include, for example, survival under stress conditions, apoptosis resistance, activation of the cellular response to DNA damage and repair of radiation-induced or chemotherapy-induced DNA damage, particularly DNA double strand breaks (DSB). One further important, yet not much investigated aspect of Akt-dependent signaling is the regulation of cell metabolism. In fact, many Akt target proteins are part of or involved in the regulation of metabolic pathways. Furthermore, recent studies revealed the importance of certain metabolites for protection against therapy-induced cell stress and the repair of therapy-induced DNA damage. Thus far, the likely interaction between deregulated activation of Akt, altered cancer metabolism and therapy resistance is not yet well understood. The present review describes the documented interactions between Akt, its target proteins and cancer cell metabolism, focusing on antioxidant defense and DSB repair. Furthermore, the review highlights potential connections between deregulated Akt, cancer cell metabolism and therapy resistance of cancer cells through altered DSB repair and discusses potential resulting therapeutic implications.
    Keywords:  Akt; DDR; DNA repair; antioxidant defense; chromatin modifications; energy metabolism; metabolism; metabolites; protein modifications
    DOI:  https://doi.org/10.3390/ijms21228563
  2. Molecules. 2020 Nov 13. pii: E5299. [Epub ahead of print]25(22):
    Jeong KY, Park M, Sim JJ, Kim HM.
      Sorafenib has been recently used for the treatment of patients with advanced colorectal cancer (CRC) and is recognized for its therapeutic value. However, the continuous use of sorafenib may cause resistance in the treatment of cancer patients. In this study, we investigated whether sorafenib exerts an enhanced anticancer effect on CRC cells via the calcium-mediated deactivation of the focal adhesion kinase (FAK) signaling pathways. The appropriate dose of sorafenib and lactate calcium salt (CaLa) for a combination treatment were determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays. Then, cell cycle analysis was performed following treatment with 2.5 μM sorafenib and/or 2.5 mM CaLa. CRC cells were found to be in the G1 phase by sorafenib treatment, and they accumulated in the sub-G1 phase with CaLa treatment. Western blots and enzyme-linked immunosorbent assays were performed to analyze the elements of the recombinant activated factor (RAF) and focal adhesion kinase (FAK) signaling cascades. Sorafenib-inhibited RAF-dependent signaling in CRC cells, however, either did not affect the expression of Akt or increased it. As the upstream signaling of FAK was suppressed by CaLa, we observed that the expression of the sub-signaling phospho (p) AKT and p-mammalian target of rapamycin was also suppressed. Treatment with a combination of sorafenib and CaLa enhanced the antitumor activity of CRC cells. The % viability of CRC cells was significantly decreased compared to the single treatment with sorafenib or CaLa, and the accumulation of Sub G1 of CRC cells was clearly confirmed. The migration ability of CRC cells was significantly reduced. The findings of this study indicate that sorafenib will show further improved antitumor efficacy against CRC due to overcoming resistance through the use of CaLa.
    Keywords:  antitumor effect; colorectal cancer; focal adhesion kinase; lactate calcium salt; sorafenib
    DOI:  https://doi.org/10.3390/molecules25225299
  3. Carcinogenesis. 2020 Nov 18. pii: bgaa119. [Epub ahead of print]
    Song X, Wang L, Wang T, Hu J, Wang J, Tu R, Su H, Jiang J, Qing G, Liu H.
      Deregulation of MYC occurs in a broad range of human cancers and often predicts poor prognosis and resistance to therapy. However, directly targeting oncogenic MYC remains unsuccessful, and indirectly inhibiting MYC emerges as a promising approach. Checkpoint kinase 1 (CHK1) is a protein kinase that coordinates the G2/M cell cycle checkpoint and protects cancer cells from excessive replicative stress. Using c-MYC-mediated T-cell acute lymphoblastic leukemia (T-ALL) and N-MYC-driven neuroblastoma as model systems, we reveal that both c-MYC and N-MYC directly bind to the CHK1 locus and activate its transcription. CHIR-124, a selective CHK1 inhibitor, impairs cell viability and induces remarkable synergistic lethality with mTOR inhibitor rapamycin in MYC-overexpressing cells. Mechanistically, rapamycin inactivates carbamoyl-phosphate synthetase 2, aspartate transcarbamoylase, and dihydroorotase (CAD), the essential enzyme for the first three steps of de novo pyrimidine synthesis, and deteriorates CHIR-124-induced replicative stress. We further demonstrate that dual treatments impede T-ALL and neuroblastoma progression in vivo. These results suggest simultaneous targeting of CHK1 and mTOR as a novel and powerful co-treatment modality for MYC-mediated tumors.
    DOI:  https://doi.org/10.1093/carcin/bgaa119
  4. Gastroenterology. 2020 Nov 17. pii: S0016-5085(20)35402-0. [Epub ahead of print]
    Chen H, Gao S, Liu W, Wong CC, Wu J, Wu J, Liu D, Gou H, Kang W, Zhai J, Li C, Su H, Wang S, Soares F, Han J, He HH, Yu J.
      BACKGROUND & AIMS: RNA N6-methyladenosine (m6A) modification has recently emerged as a new regulatory mechanism in cancer progression. We aimed to explore the role of m6A regulatory enzyme METTL3 in colorectal cancer (CRC) pathogenesis and its potential as a therapeutic target.METHODS: The expression and clinical implication of METTL3 were investigated in multiple human CRC cohorts. The underlying mechanisms of METTL3 in CRC were investigated by integrative m6A-sequencing, RNA-sequencing and ribosome profiling analyses. The efficacy of targeting METTL3 in CRC treatment was elucidated in CRC cell lines, patient-derived CRC organoids and Mettl3 knockout mouse models.
    RESULTS: Using targeted CRISPR/Cas9 dropout screening, we identified METTL3 as the top essential m6A regulatory enzyme in CRC. METTL3 was overexpressed in 62.2% (79/127) and 88.0% (44/50) of primary CRC from two independent cohorts. High METTL3 expression predicted poor survival in CRC patients (n=374, P < .01). Functionally, silencing METTL3 suppressed tumorigenesis in CRC cells, human-derived primary CRC organoids and Mettl3 knockout mouse models. We discovered the novel functional m6A methyltransferase domain of METTL3 in CRC cells by domain-focused CRISPR screen and mutagenesis assays. Mechanistically, METTL3 directly induced m6A-GLUT1-mTORC1 axis as identified by integrated m6A-sequencing, RNA-sequencing, Ribosome-sequencing and functional validation. METTL3 induced GLUT1 translation in m6A-dependent manner, which subsequently promoted glucose uptake and lactate production, leading to the activation of mTORC1 signaling and CRC development. Furthermore, inhibition of mTORC1 potentiated the anticancer effect of METTL3 silencing in CRC patient-derived organoids and METTL3 transgenic mouse models.
    CONCLUSIONS: METTL3 promotes CRC by activating m6A-GLUT1-mTORC1 axis. METTL3 is a promising therapeutic target for the treatment of CRC.
    Keywords:  Colorectal cancer; N(6)-Methyladenosine; glucose metabolism; mTORC1
    DOI:  https://doi.org/10.1053/j.gastro.2020.11.013
  5. Cancer Res. 2020 Nov 17. pii: canres.2129.2020. [Epub ahead of print]
    Harmston N, Lim JYS, Arqués O, Palmer HG, Petretto E, Virshup DM, Madan B.
      Aberrant Wnt signaling drives a number of cancers through regulation of diverse downstream pathways. Wnt/β-catenin signaling achieves this in part by increasing the expression of proto-oncogenes such as MYC and cyclins. However, global assessment of the Wnt-regulated transcriptome in vivo in genetically distinct cancers demonstrates that Wnt signaling suppresses the expression of as many genes as it activates. In this study, we examined the set of genes that are upregulated upon inhibition of Wnt signaling in Wnt-addicted pancreatic and colorectal cancer models. Decreasing Wnt signaling led to a marked increase in gene expression by activating ERK and JNK; these changes in gene expression could be mitigated in part by concurrent inhibition of MEK. These findings demonstrate that increased Wnt signaling in cancer represses MAPK activity, preventing RAS-mediated senescence while allowing cancer cells to proliferate. These results shift the paradigm from Wnt/β-catenin primarily as an activator of transcription to a more nuanced view where Wnt/β-catenin signaling drives both widespread gene repression and activation.
    DOI:  https://doi.org/10.1158/0008-5472.CAN-20-2129
  6. Cancers (Basel). 2020 Nov 13. pii: E3355. [Epub ahead of print]12(11):
    Kleeman SO, Leedham SJ.
      Wnt signaling is ubiquitously activated in colorectal tumors and driver mutations are identified in genes such as APC, CTNNB1, RNF43 and R-spondin (RSPO2/3). Adenomatous polyposis coli (APC) and CTNNB1 mutations lead to downstream constitutive activation (ligand-independent), while RNF43 and RSPO mutations require exogenous Wnt ligand to activate signaling (ligand-dependent). Here, we present evidence that these mutations are not equivalent and that ligand-dependent and ligand-independent tumors differ in terms of underlying Wnt biology, molecular pathogenesis, morphology and prognosis. These non-overlapping characteristics can be harnessed to develop biomarkers and targeted treatments for ligand-dependent tumors, including porcupine inhibitors, anti-RSPO3 antibodies and asparaginase. There is emerging evidence that these therapies may synergize with immunotherapy in ligand-dependent tumors. In summary, we propose that ligand-dependent tumors are an underappreciated separate disease entity in colorectal cancer.
    Keywords:  R-spondin; Wnt; cancer; colorectal; immunotherapy; porcupine; serrated; signaling
    DOI:  https://doi.org/10.3390/cancers12113355
  7. Front Oncol. 2020 ;10 568911
    Xu T, Zhang Y, Zhang J, Qi C, Liu D, Wang Z, Li Y, Ji C, Li J, Lin X, Hou T, Liu H, Zhang L, Han-Zhang H, Shen L, Wang X.
      Background: Early onset colorectal cancer (EO CRC) is a heterogeneous colorectal cancer subtype with obvious hereditary tendencies and increasing incidence. We sought to determine the susceptibility genes and molecular characteristics of EO CRC.Methods: 330 EO metastatic CRC (mCRC) (≤55 years) and 110 average-onset (AO) mCRC patients (>55 years) were enrolled. Capture-based targeted sequencing was performed on tumor tissue and paired white blood cells using a sequencing panel of 520 genes. The association between molecular alterations and overall survival (OS) was analyzed.
    Results: Of the 330 EO mCRC patients, 31 carried pathogenic or likely pathogenic germline mutations, with 16 of them diagnosed with lynch syndrome. Fifteen patients had germline mutations in non-mismatch repair genes, including four in MUTHY, three in RAD50, one in TP53, and eight in other genes. Twenty-nine genes were recurrently mutated in EO mCRC, including TP53, APC, KRAS, SMAD4, and BRCA2. The majority of genomic alterations were comparable between EO and AO mCRC. EO mCRC patients were more likely to have a high tumor mutation burden (p < 0.05). RNF43, RBM10, TSC, and BRAF V600E mutations were more commonly observed in EO mCRC, while APC, ASXL1, DNMT3B, and MET genes were more commonly altered in AO patients. At the pathway level, the WNT pathway was the only differentially mutated pathway between EO and AO mCRC (p < 0.0001). The wild-type WNT pathway (p = 0.0017) and mutated TGF-β pathway (p = 0.023) were associated with unfavorable OS in EO mCRC.
    Conclusions: Approximately one in 10 EO mCRC was associated with hereditary tumors. The spectrum of somatic alterations was largely comparable between EO and AO mCRC with several notable differences.
    Keywords:  early onset colorectal cancer; genomic alternation; next generation sequencing; prognosis; susceptibility gene
    DOI:  https://doi.org/10.3389/fonc.2020.568911
  8. Oncotarget. 2020 Nov 03. 11(44): 4028-4044
    Pasadi S, Muniyappa K.
      The canonical Wnt/β-catenin signalling pathway plays a crucial role in a variety of functions including cell proliferation and differentiation, tumorigenic processes and radioresistance in cancer cells. The Mre11-Rad50-Nbs1 (MRN) complex has a pivotal role in sensing and repairing DNA damage. However, it remains unclear whether a connection exists between Wnt/β-catenin signalling and the MRN complex in the repair of cisplatin-induced DNA interstrand cross-links (ICLs). Here, we report that (1) cisplatin exposure results in a significant increase in the levels of MRN complex subunits in human tumour cells; (2) cisplatin treatment stimulates Wnt/β-catenin signalling through increased β-catenin expression; (3) the functional perturbation of Wnt/β-catenin signalling results in aberrant cell cycle dynamics and the activation of DNA damage response and apoptosis; (4) a treatment with CHIR99021, a potent and selective GSK3β inhibitor, augments cisplatin-induced cell death in cancer cells. On the other hand, inactivation of the Wnt/β-catenin signalling with FH535 promotes cell survival. Consistently, the staining pattern of γH2AX-foci is significantly reduced in the cells exposed simultaneously to cisplatin and FH535; and (5) inhibition of Wnt/β-catenin signalling impedes cisplatin-induced phosphorylation of Chk1, abrogates the G2/M phase arrest and impairs recombination-based DNA repair. Our data further show that Wnt signalling positively regulates the expression of β-catenin, Mre11 and FANCD2 at early time points, but declining thereafter due to negative feedback regulation. These results support a model wherein Wnt/β-catenin signalling and MRN complex crosstalk during DNA ICL repair, thereby playing an important role in the maintenance of genome stability.
    Keywords:  Mre11–Rad50–Nbs1 complex; Wnt/β-catenin signalling; cancer; cisplatin resistance; cisplatin-induced DNA crosslinks
    DOI:  https://doi.org/10.18632/oncotarget.27777
  9. Mol Cancer Ther. 2020 Nov 17. pii: molcanther.0328.2020. [Epub ahead of print]
    Hoyle RG, Wang H, Cen Y, Zhang Y, Li J.
      Epigenetic activation of Wnt/β-catenin signaling plays a critical role in Wnt-induced tumorigenesis, notably in colorectal cancers (CRCs). KDM3 and KDM4 histone demethylases have been reported to promote oncogenic Wnt signaling through demethylation of H3K9 on Wnt target gene promoters and are suggested to be potential therapeutic targets. However, potent inhibitors for these regulators are still not available yet. In addition, which family is most responsible for activation of Wnt target genes and Wnt induced oncogenesis is not well documented, specifically in CRC. In this study, we characterized the functional redundancy and differences between KDM3 and KDM4 in regards to regulating Wnt signaling. Our data suggests that KDM3 may play a more essential role than KDM4 in regulating oncogenic Wnt signaling in human CRC. We also identified that IOX1, a known histone demethylase inhibitor, significantly suppresses Wnt target gene transcription and CRC tumorigenesis. Mechanistically, IOX1 inhibits the enzymatic activity of KDM3 by binding to the Jumonji C domain and thereby preventing the demethylation of H3K9 on Wnt target gene promoters. Taken together, our data not only identified the critical mechanisms by which IOX1 suppressed Wnt/β-catenin signaling and CRC tumorigenesis through inhibition of KDM3, but also suggested that IOX1 may represent an attractive small molecule lead for future drug design and discovery.
    DOI:  https://doi.org/10.1158/1535-7163.MCT-20-0328
  10. Cell Death Dis. 2020 Nov 15. 11(11): 982
    Zheng GW, Tang MM, Shu CY, Xin WX, Zhang YH, Chi BB, Shi MR, Guo X, Zhang ZZ, Lian XY.
      Residual disease is the major cause for colorectal cancer (CRC) relapse. Herein, we explore whether and how a natural molecule CADPE killed heterogenic populations in a panel of CRC cell lines with KRAS/BRAF mutations that are natively resistant to EGFR- or VEGFR-targeted therapy, without sparing persistent cells, a reservoir of the disease relapse. Results showed that CADPE killed the tumor bulk and residual cells in the panel of CRC cell lines, rapidly inactivated c-Myc, STAT3, and NF-κB, and then decreased the protein levels of key signaling molecules for CRC, such as β-catenin, Notch1, and the nodes of mTOR pathways; eukaryotic translation initiation factors (eIF4F); anti-apoptotic proteins (Bcl-xl, Mcl-1, and survivin); and stemness-supporting molecules (CD133, Bim-1, and VEGF). In terms of mechanism of action, concurrent downregulation of Mcl-1, Bcl-xl, and survivin was necessary for CADPE to kill CRC bulk cells, while additional depletion of CD133 and VEGF proteins was required for killing the residual CRC cells. Moreover, the disabled c-Myc, STAT3, NF-κB, and eIF4F were associated with the broadly decreased levels of anti-apoptosis proteins and pro-stemness proteins. Consistently, CADPE suppressed CRC tumor growth associated with robust apoptosis and depleted levels of c-Myc, STAT3, NF-κB, eIF4F, anti-apoptotic proteins, and pro-stemness proteins. Our findings showed the promise of CADPE for treating CRC and suggested a rational polytherapy that disables c-Myc, STAT3, NF-κB, and eIF4F for killing CRC residual disease.
    DOI:  https://doi.org/10.1038/s41419-020-03191-5
  11. Oncologist. 2020 Nov 15.
    Sobrero A, Lenz HJ, Eng C, Scheithauer W, Middleton G, Chen W, Esser R, Nippgen J, Burris H.
      BACKGROUND: The multicenter, open-label, randomized, phase 3 EPIC study (EMR 062202-025) investigated cetuximab plus irinotecan vs irinotecan in patients with epidermal growth factor receptor-detectable metastatic colorectal cancer (mCRC) that progressed on first-line fluoropyrimidine- and oxaliplatin-based chemotherapy; we report the outcomes of patients with RAS-wild-type (wt) disease.MATERIALS AND METHODS: Available DNA samples from RAS-unselected patients (n = 1164 of 1298 [89.7%]) were reanalyzed for RAS mutations using BEAMing. Baseline characteristics, efficacy, safety, and post-study therapy were assessed. RAS-wt status was defined as a mutated RAS allele frequency of ≤5%, with all relevant alleles being analyzable.
    RESULTS: Baseline characteristics were comparable between the groups (N = 452 patients with RAS-wt mCRC; cetuximab plus irinotecan n = 231, irinotecan n = 221) and between the RAS-wt and RAS-unselected populations. In the cetuximab plus irinotecan vs irinotecan arms, median overall survival was 12.3 vs 12.0 months, median progression-free survival (PFS) was 5.4 vs 2.6 months, and objective response rate (ORR) was 29.4% vs 5.0%, respectively. Quality of life (QoL) was improved in the cetuximab plus irinotecan arm. Serious adverse events occurred in 45.4% (cetuximab plus irinotecan) and 42.4% (irinotecan) of patients. In total, 47.1% of patients in the irinotecan arm received subsequent cetuximab therapy.
    CONCLUSION: PFS, ORR, and QoL were improved with cetuximab plus irinotecan as a second-line treatment in patients with RAS-wt mCRC, confirming that cetuximab-based therapy is suitable in this population. Almost half of patients in the irinotecan arm received post-study cetuximab, masking a potential OS benefit of cetuximab addition.
    IMPLICATIONS FOR PRACTICE: Cetuximab is approved for the treatment of RAS-wild-type metastatic colorectal cancer (mCRC). In this retrospective analysis of the phase 3 EPIC study (cetuximab plus irinotecan versus irinotecan alone as second-line treatment in patients with RAS-unselected mCRC), the subgroup of patients with RAS-wild-type mCRC who received cetuximab plus irinotecan had improved progression-free survival, objective response rate, and quality of life compared with the RAS-unselected population. These findings suggest that cetuximab-based therapy is a suitable second-line treatment for patients with RAS-wild-type mCRC.
    Keywords:  EPIC; RAS; cetuximab; irinotecan; metastatic colorectal cancer
    DOI:  https://doi.org/10.1002/onco.13591
  12. J Biol Chem. 2020 Nov 20. pii: jbc.RA120.014682. [Epub ahead of print]
    Chen G, Zhou G, Lotvola A, Granneman JG, Wang J.
      ABHD5 is an essential coactivator of ATGL, the rate-limiting triglyceride (TG) lipase in many cell types. Importantly, ABHD5 also functions as a tumor suppressor, and ABHD5 mRNA expression levels correlate with patient survival for several cancers. Nevertheless, the mechanisms involved in ABHD5-dependent tumor suppression are not known. We found that overexpression of ABHD5 induces cell-cycle arrest at the G1 phase and causes growth retardation in a panel of prostate cancer cells. Transcriptomic profiling and biochemical analysis revealed that genetic or pharmacological activation of lipolysis by ABHD5 potently inhibits mTORC1 signaling, leading to a significant downregulation of protein synthesis. Mechanistically, we found that ABHD5 elevates intracellular AMP content, which activates AMPK, leading to inhibition of mTORC1. Interestingly, ABHD5-dependent suppression of mTORC1 was abrogated by pharmacological inhibition of DGAT1 or DGAT2, isoenzymes that re-esterify fatty acids in a process that consumes ATP. Collectively, this study maps out a novel molecular pathway crucial for limiting cancer cell proliferation, in which ABHD5-mediated lipolysis creates an energy-consuming futile cycle between TG hydrolysis and resynthesis, leading to inhibition of mTORC1 and cancer cell growth arrest.
    Keywords:  lipid signaling; lipolysis; metabolic regulation; tumor cell biology; tumor metabolism
    DOI:  https://doi.org/10.1074/jbc.RA120.014682
  13. Onco Targets Ther. 2020 ;13 11505-11516
    Xue Y, Li PD, Tang XM, Yan ZH, Xia SS, Tian HP, Liu ZL, Zhou T, Tang XG, Zhang GJ.
      Purpose: Colorectal cancer (CRC) is one of the most common malignancies in the world. The prognosis of advanced CRC is still poor. The purpose of this study was to identify a gene expression profile associated with CRC that may contribute to the early diagnosis of CRC and improve patient prognosis.Patients and Methods: Five pairs of CRC tissues and paracancerous tissues were used to identify causative genes using microarray assays. The prognostic value of Cytochrome C Oxidase Assembly Factor 1 Homolog (COA1) in CRC was assessed in 90 CRC patients. Loss-of-function assays, cell proliferation assays using Celigo and MTT, colony formation assays, a subcutaneous xenograft mouse model, and apoptosis assays were used to define the effects of downregulation of COA1 in CRC cells in vitro and in vivo. The underlying molecular mechanisms of COA1 in CRC were also investigated.
    Results: The causative gene COA1 was identified through microarray analysis. COA1 expression in CRC was notably associated with pathologic differentiation, tumor size, and tumor depth. COA1 expression may act as an independent prognostic factor for overall survival of CRC. Knockdown of COA1 inhibited the proliferation of CRC cells in vitro and the tumorigenicity of CRC cells in vivo. Decreased COA1 expression induced apoptosis of CRC cells. Based on the microarray assay results comparing HCT116 cells transfected with lentivirus encoding anti-COA1 shRNA or negative control shRNA, ingenuity pathway analysis (IPA) revealed that the PI3K/AKT signaling pathway was significantly enriched. Moreover, CCND1, mTOR, AKT1, and MDM2 were identified as the downstream genes of COA1.
    Conclusion: These findings demonstrate that COA1 promotes CRC cell proliferation and inhibits apoptosis by regulating the PI3K/AKT signaling pathway. Our results implicate COA1 as a potential oncogene involved in tumor growth and progression of CRC.
    Keywords:  COA1; PI3K/AKT signaling; apoptosis; colorectal cancer; proliferation
    DOI:  https://doi.org/10.2147/OTT.S279024
  14. Am J Transl Res. 2020 ;12(10): 6445-6454
    Li J, Zheng Y, Li X, Dong X, Chen W, Guan Z, Zhang C.
      OBJECTIVE: The dysregulation of deubiquitinating enzymes is important in the development of many cancers, including colorectal cancer (CRC). However, the precise function and potential mode of action of the deubiquitinating enzyme UCHL3 in CRC progression are poorly elucidated.METHODS: The expression levels of UCHL3 in patient samples were analyzed by western blotting, real-time PCR and immunohistochemistry and its association with overall survival was analyzed using Kaplan-Meier method. Colony formation, CCK-8 and Transwell were used to examine the effects of UCHL3 knockdown or over-expression on CRC cells growth, invasion and migration. The functional effects of UCHL3 and SOX12 on tumor growth were further examined using xenograft tumor mouse models in vivo.
    RESULTS: Here, we found high expression of UCHL3 in CRC tissues which showed an association with the development of tumor and CRC patient survival. Studies conducted in vitro showed that UCHL3 overexpression facilitates proliferation, invasion, migration, and EMT (epithelial-mesenchymal transition) in cells of CRC, and a knockdown of UCHL3 had a reverse effect. Likewise, experiments conducted in vivo also showed enhanced tumor growth due to UCHL3 overexpression. In addition, UCHL3 was found regulates SOX12 expression in CRC cells. PI3K/AKT/mTOR pathway is required for UCHL3-mediated SOX12 expression. Mechanically, UCHL3 regulates SOX12 via AKT/mTOR signaling pathway and facilitated tumor progression.
    CONCLUSION: UCHL3 plays an oncogenic role through the AKT/mTOR/SOX12 axis and can be considered as a potential target for therapy and CRC prognostic biomarker.
    Keywords:  AKT/mTOR; CRC; SOX12; UCHL3; tumor growth
  15. Mol Aspects Med. 2020 Nov 17. pii: S0098-2997(20)30135-7. [Epub ahead of print] 100933
    Piccinin E, Cariello M, Moschetta A.
      Colorectal cancer (CRC) is one of the most commonly occurring cancers worldwide. Although several genetic alterations have been associated with CRC onset and progression, nowadays the reprogramming of cellular metabolism has been recognized as a fundamental step of the carcinogenic process. Intestinal tumor cells frequently display an aberrant activation of lipid metabolism. Indeed, to satisfy the growing needs of a continuous proliferation, cancer cells can either increase the uptake of exogenous lipids or upregulate the endogenous lipogenesis and cholesterol synthesis. Therefore, strategies aimed at limiting lipid accumulation are now under development in order to counteract malignancies. Two major players of lipids metabolism have been so far identified for their contribution to CRC development: the nuclear receptor Liver X Receptor (LXRs) and the enzyme Stearoyl-CoA Desaturase 1 (SCD1). Whereas LXR is mainly recognized for its role as a cholesterol sensor, finally promoting the loss of cellular cholesterol and whole-body homeostasis, SCD1 acts as the major regulator of new fatty acids, finely tuning the monounsaturated fatty acids (MUFA) to saturated fatty acids (SFA) ratio. Intriguingly, SCD1 is directly regulated by LXRs. Despite LXRs agonists have elicited great interest as a promising therapeutic target for cancer, LXR's ability to induce SCD1 and new fatty acids synthesis represent a major obstacle in the development of new effective treatments. Thus, further investigations are required to fully dissect the concomitant modulation of both players, to develop specific therapies aimed at blocking intestinal cancer cells proliferation, eventually counteracting CRC progression.
    Keywords:  Colorectal cancer; Lipid metabolism; Liver X receptor; Nuclear receptor; Stearoyl-CoA Desaturase
    DOI:  https://doi.org/10.1016/j.mam.2020.100933
  16. Br J Cancer. 2020 Nov 19.
    Jácome AA, Vreeland TJ, Johnson B, Kawaguchi Y, Wei SH, Nancy You Y, Vilar E, Vauthey JN, Eng C.
      BACKGROUND: The impact of molecular aberrations on survival after resection of colorectal liver metastases (CLM) in patients with early-age-onset (EOCRC) versus late-age-onset colorectal cancer (LOCRC) is unknown.METHODS: Patients who underwent liver resection for CLM with known RAS, BRAF and MSI status were retrospectively studied. The prognostic impact of RAS mutations by age was analysed with age as a categorical variable and a continuous variable.
    RESULTS: The study included 573 patients, 192 with EOCRC and 381 with LOCRC. The younger the age of onset of CRC, the greater the negative impact on overall survival of RAS mutations in the LOCRC, EOCRC, and ≤40 years (hazard ratio (HR), 1.64 (95% confidence interval (CI), 1.23-2.20), 2.03 (95% CI, 1.30-3.17), and 2.97 (95% CI, 1.44-6.14), respectively. Age-specific mortality risk and linear regression analysis also demonstrated that RAS mutations had a greater impact on survival in EOCRC than in LOCRC (slope: -4.07, 95% CI -8.10 to 0.04, P = 0.047, R2 = 0.08).
    CONCLUSION: Among patients undergoing CLM resection, RAS mutations have a greater negative influence on survival in patients with EOCRC, more so in patients ≤40 years, than in patients with LOCRC and should be considered as a prognostic factor in multidisciplinary treatment planning.
    DOI:  https://doi.org/10.1038/s41416-020-01169-w