Simultaneous inhibition of IGF1R and EGFR enhances the efficacy of standard treatment for colorectal cancer by the impairment of DNA repair and the induction of cell death

Topical Ozone Accelerates Diabetic Wound Healing by Promoting Re-Epithelialization through the Activation of IGF1R-EGFR Signaling

Ozonated oil increases the healing of chronic diabetic wounds, but the underlying mechanisms remain unclear. We investigated the effect of topical ozonated oil on wound healing in mice with diabetes with diet-induced obesity and further elucidated the role of EGFR and IGF1R signaling in diabetic wound healing. We found that topical ozonated oil accelerated wound healing; increased phosphorylation of IGF1R, EGFR, and VEGFR; and improved vascularization at the wound leading edge in mice with diabetes with diet-induced obesity. Exposure of normal epidermal keratinocytes to ozonated medium (20 μM for 2 hours daily) increased cell proliferation and migration distance by increasing phosphorylation of IGF1R and EGFR and downstream phosphoinositide 3-kinase, protein kinase B, and extracellular signal-regulated kinase. These findings shed light on the mechanism for topical ozone action in chronic wounds and support its potential therapeutic application.

Resveratrol induces DNA damage-mediated cancer cell senescence through the DLC1-DYRK1A-EGFR axis

Inducing cell senescence is widely regarded as a potent tumor suppression mechanism. Resveratrol has attracted increasing attention for its capacity to prevent and suppress cancer. However, the mechanism of resveratrol on the induction of cancer cell senescence has not been well clarified. Our results showed that resveratrol inhibited cell viability and colony formation and promoted cell senescence along with augmentation of SA-β-gal activity and modulation of senescence-associated molecular markers p53, p21 and LaminB protein in breast and liver cancer cells. The underlying mechanism was that resveratrol increased ROS generation to enhance tumor suppressor gene DLC1 expression, and DLC1 further inhibited the DYRK1A-EGFR axis to trigger DNA damage accompanied by up-regulation of the DNA double strand break marker protein γH2AX and down-regulation of the DNA repair related proteins p-BRCA1 and RAD51, eventually leading to cancer cell senescence. Resveratrol also effectively inhibited the volume of transplanted tumor with increased SA-β-gal activity and DLC1 level in a chicken embryo allantoic membrane xenograft tumor model. This is the first report to investigate whether resveratrol induces DNA damage-mediated cancer cell senescence through the DLC1-DYRK1A-EGFR axis, which could provide a solid base for resveratrol's application in cancer prevention and clinical treatment as a food additive or adjuvant therapies.

Emerging Role of Oxidative Stress on EGFR and OGG1-BER Cross-Regulation: Implications in Thyroid Physiopathology

Thyroid diseases have a complex and multifactorial aetiology. Despite the numerous studies on the signals referable to the malignant transition, the molecular mechanisms concerning the role of oxidative stress remain elusive. Based on its strong oxidative power, H2O2 could be responsible for the high level of oxidative DNA damage observed in cancerous thyroid tissue and hyperactivation of mitogen-activated protein kinase (MAPK) and PI3K/Akt, which mediate ErbB signaling. Increased levels of 8-oxoG DNA adducts have been detected in the early stages of thyroid cancer. These DNA lesions are efficiently recognized and removed by the base excision repair (BER) pathway initiated by 8-oxoG glycosylase1 (OGG1). This study investigated the relationships between the EGFR and OGG1-BER pathways and their mutual regulation following oxidative stress stimulus by H2O2 in human thyrocytes. We clarified the modulation of ErbB receptors and their downstream pathways (PI3K/Akt and MAPK/ERK) under oxidative stress (from H2O2) at the level of gene and protein expression, according to the mechanism defined in a human non-pathological cell system, Nthy-ori 3-1. Later, on the basis of the results obtained by gene expression cluster analysis in normal cells, we assessed the dysregulation of the relationships in a model of papillary thyroid cancer with RET/PTC rearrangement (TPC-1). Our observations demonstrated that a H2O2 stress may induce a physiological cross-regulation between ErbB and OGG1-BER pathways in normal thyroid cells (while this is dysregulated in the TPC-1 cells). Gene expression data also delineated that MUTYH gene could play a physiological role in crosstalk between ErbB and BER pathways and this function is instead lost in cancer cells. Overall, our data on OGG1 protein expression suggest that it was physiologically regulated in response to oxidative modulation of ErbB, and that these might be dysregulated in the signaling pathway involving AKT in the progression of thyroid malignancies with RET/PTC rearrangements.

Hsa-miR-6165 downregulates insulin-like growth factor-1 receptor (IGF-1R) expression and enhances apoptosis in SW480 cells

MicroRNAs are small non-coding RNAs that are implicated in various biological processes. Hsa-miR-6165 (miR-6165), located in the p75NTR gene, is known to induce apoptosis in human cell lines, but its mechanism of action is not fully understood yet. Here, we predicted the insulin-like growth factor 1 receptor (IGF-1R) gene as a bona fide target for miR-6165. The overexpression of miR-6165 in SW480 cells resulted in significant downregulation of IGF-1R expression as detected by real time quantitative polymerase chain reaction (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA). Also, it resulted in reduced transcript levels of AKT2, AKT3, PI3KR3, PI3KR5, CCND1, c-MYC and P21 genes detected by RT-qPCR analysis. In addition, a direct interaction between miR-6165 and a 3'UTR sequence of the IGF-1R gene was verified through a dual luciferase assay. Furthermore, miR-6165 and IGF-1R showed opposite patterns of expression during the neural differentiation process of NT2 cells. Annexin V analysis and MTT assay showed that miR-6165 overexpression was followed by increased apoptosis and reduced the viability rate of SW480 cells. Moreover, a lower expression level of miR-6165 was detected in high-grade colorectal tumors compared with low-grade tumors. Taken together, the results of our study suggest a tumor suppressive role of miR-6165 in colorectal cancer, which seems to take place by regulating IGF-1R gene expression.

Targeting DNA-PK overcomes acquired resistance to third-generation EGFR-TKI osimertinib in non-small-cell lung cancer

The third-generation of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs), represented by osimertinib, has achieved remarkable clinical outcomes in the treatment of non-small-cell lung cancer (NSCLC) with EGFR mutation. However, resistance eventually emerges in most patients and the underlying molecular mechanisms remain to be fully understood. In this study, we generated an osimertinib-acquired resistant lung cancer model from a NSCLC cell line H1975 harboring EGFR L858R and T790M mutations. We found that the capacity of DNA damage repair was compromised in the osimertinib resistant cells, evidenced by increased levels of γH2AX and higher intensity of the comet tail after withdrawal from cisplatin. Pharmacological inhibiting the activity or genetic knockdown the expression of DNA-PK, a key kinase in DNA damage response (DDR), sensitized the resistant cells to osimertinib. Combination of osimertinib with the DNA-PK inhibitor, PI-103, or NU7441, synergistically suppressed the proliferation of the resistant cells. Mechanistically, we revealed that DNA-PK inhibitor in combination with osimertinib resulted in prolonged DNA damage and cell cycle arrest. These findings shed new light on the mechanisms of osimertinib resistance in the aspect of DNA repair, and provide a rationale for targeting DNA-PK as a therapeutic strategy to overcome osimertinib-acquired resistance in NSCLC.

NCK1-AS1 enhances glioma cell proliferation, radioresistance and chemoresistance via miR-22-3p/IGF1R ceRNA pathway

Glioma is the deadliest disease in human central nerve system. Abnormal expression of long noncoding RNA (lncRNA) expression has been demontrated to be implicated in various cancers. The oncogenic role of lncRNA NCK1-AS1 has been validated in cervical cancer, wheras its role in glioma remians obscure. Our research findings suggested that NCK1-AS1 was upregulated in glioma tissues and cells. NCK1-AS1 deficiency hindered cell proliferation and enhanced cell apoptosis. Additionally, the chemoresistance and radioresistance of glioma cells were impaired by NCK1-AS1 depletion. Moreover, miR-22-3p, a downstream gene of NCK1-AS1, could weaken glioma cell chemoresistance and radioresistance. Similarly, IGF1R was the downstream target gene of miR-22-3p. Further mechanism and function assays demonstrated that NCK1-AS1 promoted glioma cell growth, chemoresistance and radioresistance via sponging miR-22-3p to upregulate IGF1R. Finally, the tumor facilitator function of NCK1-AS1 was also verified by in vivo experiments. Taken together, NCK1-AS1 contributes to glioma cell proliferation, radioresistance and chemoresistance via miR-22-3p/IGF1R ceRNA pathway, which might provide a new insight for improving the radiotherapy and chemotherapy treatments of glioma.

The inhibitory effect of ECG and EGCG dimeric procyanidins on colorectal cancer cells growth is associated with their actions at lipid rafts and the inhibition of the epidermal growth factor receptor signaling

Colorectal cancer (CRC) is one of the most common cancers worldwide. Epidemiological studies indicate that consumption of fruits and vegetables containing procyanidins is associated with lower CRC risk. This study investigated the capacity of two dimeric procyanidins composed of epicatechin gallate (ECG) or epigallocatechin gallate (EGCG) isolated from persimmons, to inhibit CRC cell growth and promote apoptosis, characterizing the underlying mechanisms. ECG and EGCG dimers reduced the growth of five human CRC cell lines in a concentration (10-60 μM)- and time (24-72 h)-dependent manner, with a 72 h-IC50 value in Caco-2 cells of 10 and 30 μM, respectively. ECG and EGCG dimers inhibited Caco-2 cell proliferation by arresting the cell cycle in G2/M phase and by inducing apoptosis via the mitochondrial pathway. In addition, ECG and EGCG dimers inhibited cell migration, invasion, and adhesion, decreasing the activity of matrix metalloproteinases (MMP-2/9). Mechanistically, ECG and EGCG dimers inhibited the activation of lipid raft-associated epidermal growth factor (EGF) receptor (EGFR), without affecting its localization at lipid rafts. In particular, ECG and EGCG dimers reduced EGFR phosphorylation at Tyr1068 residue, prevented EGFR dimerization and activation upon stimulation, and induced EGFR internalization both in the absence and presence of EGF. Furthermore, ECG and EGCG dimers increased EGFR phosphorylation at Tyr1045 residue, providing a docking site for ubiquitin ligase c-Cbl and induced EGFR degradation by the proteasome. Downstream of EGFR, ECG and EGCG dimers inhibited the activation of the MEK/ERK1/2 and PI3K/AKT signaling pathways, downregulating proteins involved in the modulation of cell survival. In conclusion, ECG and EGCG dimers reduced CRC cell growth by inhibiting EGFR activation at multiple steps, including the disruption of lipid rafts integrity and promoting EGFR degradation. These results shed light on a potential molecular mechanism on how procyanidins-rich diets may lower CRC risk.

MiR-19a-3p regulates the Forkhead box F2-mediated Wnt/β-catenin signaling pathway and affects the biological functions of colorectal cancer cells

BACKGROUND

Colorectal cancer (CRC) is one of the most common malignancies worldwide.

AIM

To explore the expression of microRNA miR-19a-3p and Forkhead box F2 (FOXF2) in patients with CRC and the relevant mechanisms.

METHODS

Sixty-two CRC patients admitted to the hospital were enrolled into the study group, and sixty healthy people from the same period were assigned to the control group. Elbow venous blood was sampled from the patients and healthy individuals, and blood serum was saved for later analysis. MiR-19a-3p mimics, miR-19a-3p inhibitor, miR-negative control, small interfering-FOXF2, and short hairpin-FOXF2 were transfected into HT29 and HCT116 cells. Then quantitative polymerase chain reaction was performed to quantify the expression of miR-19a-3p and FOXF2 in HT29 and HCT116 cells, and western blot (WB) analysis was conducted to evaluate the levels of FOXF2, glycogen synthase kinase 3 beta (GSK-3β), phosphorylated GSK-3β (p-GSK-3β), β-catenin, p-β-catenin, α-catenin, N-cadherin, E-cadherin, and vimentin. The MTT, Transwell, and wound healing assays were applied to analyze cell proliferation, invasion, and migration, respectively, and the dual luciferase reporter assay was used to determine the correlation of miR-19a-3p with FOXF2.

RESULTS

The patients showed high serum levels of miR-19a-3p and low levels of FOXF2, and the area under the curves of miR-19a-3p and FOXF2 were larger than 0.8. MiR-19a-3p and FOXF2 were related to sex, tumor size, age, tumor-node-metastasis staging, lymph node metastasis, and differentiation of CRC patients. Silencing of miR-19a-3p and overexpression of FOXF2 suppressed the epithelial-mesenchymal transition, invasion, migration, and proliferation of cells. WB analysis revealed that silencing of miR-19a-3p and FOXF2 overexpression significantly suppressed the expression of p-GSK-3β, β-catenin, N-cadherin, and vimentin; and increased the levels of GSK-3β, p-β-catenin, α-catenin, and E-cadherin. The dual luciferase reporter assay confirmed that there was a targeted correlation of miR-19a-3p with FOXF2. In addition, a rescue experiment revealed that there were no differences in cell proliferation, invasion, and migration in HT29 and HCT116 cells co-transfected with miR-19a-3p-mimics+sh-FOXF2 and miR-19a-3p-inhibitor+si-FOXF2 compared to the miR-negative control group.

CONCLUSION

Inhibiting miR-19a-3p expression can upregulate the FOXF2-mediated Wnt/β-catenin signaling pathway, thereby affecting the epithelial-mesenchymal transition, proliferation, invasion, and migration of cells. Thus, miR-19a-3p is likely to be a therapeutic target in CRC.

Overexpression of IRS-4 Correlates with Procaspase 3 Levels in Tumoural Tissue of Patients with Colorectal Cancer

We reported that insulin receptor substrate 4 (IRS-4) levels increased in tissue from colorectal cancer (CRC) patients and promoted retinoblastoma-cyclin-dependent kinase activation. The aim of the present study was to evaluate the effect of IRS-4 on IGF-1 receptor pathway and its impact on procaspase 3 and PARP expression in RKO and HepG2 cancer cell lines. The results obtained in vitro were compared with those obtained from biopsies of patients with CRC (n = 18), tubulovillous adenomas (TA) (n = 2) and in matched adjacent normal colorectal (MANC) tissue (n = 20). IRS-4 overexpression in cultured cells induced the overactivation of IGF-1/BRK/AKT/GSK-3/β-catenin/cyclin D1 pathways, which led to increased expression of procaspase 3 and PARP protein levels. Studies carried out on CRC and TA tissues revealed the overactivation of the IGF-1 receptor signalling pathway, as well as the overexpression of procaspase 3 and PARP in tumoural tissue with respect to MANC tissue. The upregulation of IRS-4 in tumoural samples correlated significantly with the increase in pIGF-1 receptor (Tyr 1165/1166) (r = 0.84; p < 0.0001), procaspase 3 (r = 0. 77; p < 0. 0005) and PARP (r = 0. 89; p < 0. 0005). Similarly, we observed an increase in the proteolysis of procaspase 3 in tumoural tissue with respect to MANC tissue, which correlated significantly with the degradation of PARP (r = 0.86; p < 0.0001), p53 (r = 0.84; p < 0.0001), and GSK-3 (r = 0.78; p < 0.0001). The stratification of patient samples using the TNM system revealed that procaspase 3 and caspase 3 increased gradually with T values, which suggests their involvement in the size and local invasion of primary tumours. Taken together, our findings suggest that IRS-4 overexpression promotes the activation of the IGF-1 receptor pathway, which leads to the increase in procaspase 3 levels in CRC.

IGF1/IGF1R and microRNA let-7e down-regulate each other and modulate proliferation and migration of colorectal cancer cells

MicroRNA let-7 has been reported to be down-regulated in several human cancers and is now characterized as a tumor suppressor. IGF1R is over-expressed in many cancers and IGF1/IGF1R pathway is attractive target for anticancer therapy. However, the crosstalk between let-7 and IGF1/IGF1R are largely unknown. The present study showed IGF1R were significantly over-expressed in colorectal cancer tissues compared with adjacent normal tissues through immunohistochemical analysis. qRT-PCR results showed that let-7a, let-7b and let-7e were down-regulated in colorectal cancer tissues. Bioinformatics analysis revealed that both IGF1 and IGF1R mRNA are potential targets for let-7 miRNA family. Ectopic transfection of let-7e led to a significant reduction in IGF1R at protein level and their downstream Akt inhibition, as well as a reduction in cell proliferation, migration and invasion in colorectal cancer cells, while inhibition of let-7e enhanced the expression of IGF1R. On the other hand, IGF1 stimulation can significantly down-regulate the expression of let-7e in colorectal cancer cells. Taken together, our findings identify a negative feedback regulation between let-7e and IGF1/IGF1R, and suggest that let-7e could be used in IGF1R-targeted therapeutics in anticancer therapy.

ABBREVIATIONS

IGF1: insulin-like growth factor 1; IGF1R: IGF1 receptor; miRNA: microRNA; CRC: colorectal cancer; EGFR: epidermal growth factor receptor; HRP: horseradish peroxidase; MTT: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide; p-Akt: phospho-Akt; PI3K: phosphoinositide 3-kinase; qRT-PCR: quantitative reverse transcription-PCR; IHC: immunohistochemical; siRNA: small interfering RNA; 3'-UTR: 3'-untranslated region.

MiR-185 enhances radiosensitivity of colorectal cancer cells by targeting IGF1R and IGF2

OBJECTIVE

Radioresistance is a significant obstacle for effective treatment of colorectal cancer (CRC). Recent studies have indicated that miR-185 inhibits proliferation, survival, and invasion of CRC; however, the role of this miRNA in radioresistance of CRC has not been identified yet. The aim of this study is to investigate the role of miR-185 in radiosensitivity of CRC.

METHODS

After transfecting the cells with mimic miR-185, expressions of IGF1R and IGF2 were evaluated by real-time PCR and western blot. The radiation response of transfected cells was also examined by colony forming assay. Sub-G1 fraction analysis through flow cytometry and caspase 3 activity was used to evaluate apoptosis.

RESULTS

The results of real-time PCR and western blot indicated that IGF1R and IGF2 are downregulated in the transfected cells. Colony forming assay revealed that transfected cells were more radiosensitive than other cells. On the other hand,following irradiation the rate of apoptosis was significantly higher in the transfected cells than in the other cells.

CONCLUSION

In summary, our study is the first to show that upregulation of miR-185 enhances the sensitivity of CRC cells to ionizing radiation. miR-185 may act as a novel biomarker of radioresistance and may clinically enhance the radiation response of CRC.

Relation of the IGF/IGF1R system to autophagy in colitis and colorectal cancer

Metabolic syndrome (MetS), as a chronic inflammatory disorder has a potential role in the development of inflammatory and cancerous complications of the colonic tissue. The interaction of DNA damage and inflammation is affected by the insulin-like growth factor 1 receptor (IGF1R) signaling pathway. The IGF1R pathway has been reported to regulate autophagy, as well, but sometimes through a bidirectional context. Targeting the IGF1R-autophagy crosstalk could represent a promising strategy for the development of new antiinflammatory and anticancer therapies, and may help for subjects suffering from MetS who are at increased risk of colorectal cancer. However, therapeutic responses to targeted therapies are often shortlived, since a signaling crosstalk of IGF1R with other receptor tyrosine kinases or autophagy exists, leading to acquired cellular resistance to therapy. From a pharmacological point of view, it is attractive to speculate that synergistic benefits could be achieved by inhibition of one of the key effectors of the IGF1R pathway, in parallel with the pharmacological stimulation of the autophagy machinery, but cautiousness is also required, because pharmacologic IGF1R modulation can initiate additional, sometimes unfavorable biologic effects.