Hypoxia Activates Notch4 via ERK/JNK/P38 MAPK Signaling Pathways to Promote Lung Adenocarcinoma Progression and Metastasis

The lncRNA CADM2-AS1 promotes gastric cancer metastasis by binding with miR-5047 and activating NOTCH4 translation

Background

Multi-organ metastasis has been the main cause of death in patients with Gastric cancer (GC). The prognosis for patients with metastasized GC is still very poor. Long noncoding RNAs (lncRNAs) always been reported to be closely related to cancer metastasis.

Methods

In this paper, the aberrantly expressed lncRNA CADM2-AS1 was identified by lncRNA-sequencing in clinical lymph node metastatic GC tissues. Besides, the role of lncRNA CADM2-AS1 in cancer metastasis was detected by Transwell, Wound healing, Western Blot or other assays in vitro and in vivo. Further mechanism study was performed by RNA FISH, Dual-luciferase reporter assay and RT-qPCR. Finally, the relationship among lncRNA CADM2-AS1, miR-5047 and NOTCH4 in patient tissues was detected by RT-qPCR.

Results

In this paper, the aberrantly expressed lncRNA CADM2-AS1 was identified by lncRNA-sequencing in clinical lymph node metastatic GC tissues. Besides, the role of lncRNA CADM2-AS1 in cancer metastasis was detected in vitro and in vivo. The results shown that overexpression of the lncRNA CADM2-AS1 promoted GC metastasis, while knockdown inhibited it. Further mechanism study proved that lncRNA CADM2-AS1 could sponge and silence miR-5047, which targeting mRNA was NOTCH4. Elevated expression of lncRNA CADM2-AS1 facilitate GC metastasis by up-regulating NOTCH4 mRNA level consequently. What's more, the relationship among lncRNA CADM2-AS1, miR-5047 and NOTCH4 was further detected and verified in metastatic GC patient tissues.

Conclusions

LncRNA CADM2-AS1 promoted metastasis in GC by targeting the miR-5047/NOTCH4 signaling axis, which may be a potential target for GC metastasis.

The p38 MAPK/snail signaling axis participates in cadmium-induced lung cancer cell migration and invasiveness

To determine that p38 MAPK activation contributes to the migration and invasion of lung cancer cells caused by cadmium (Cd). A549 lung cancer cell migration and invasion were assessed using a transwell plate system, and the role of p38 was determined by knocking down p38 activity with two different inhibitors of p38. The activity of p38 was measured by western blot analysis using phospho-specific p38 antibodies and normalized to blots using antibodies directed to total p38 proteins. Snail transcripts were measured using qRT-PCR. The inhibition of p38 blocked Cd-induced migration and invasion, which correlated with an increased activation of p38 as a function of dose and time. Furthermore, Cd-induced activation of p38 MAPK controlled the increase of snail mRNA expression. The p38 MAPK/snail signaling axis was involved in Cd-induced lung cancer cell migration and invasion.

Notch signaling and targeted therapy in non-small cell lung cancer

The Notch signaling pathway plays pivotal roles in cell proliferation, stemness and invasion of non-small cell lung cancer (NSCLC). The human Notch family consists of four receptors, namely Notch1, Notch2, Notch3, and Notch4. These receptors are transmembrane proteins that play crucial roles in various cellular processes. Notch1 mostly acts as a pro-carcinogenic factor in NSCLC but sometimes acts as a suppressor. Notch2 has been demonstrated to inhibit the growth and progression of NSCLC, whereas Notch3 facilitates these biological behaviors of NSCLC. The role of Notch4 in NSCLC has not been fully elucidated, but it is evident that Notch4 promotes tumor progression. At present, drugs targeting the Notch pathway are being explored for NSCLC therapy, a majority of which are already in the stage of preclinical research and clinical trials, with bright prospects in the clinical treatment of NSCLC.

Hypoxia improves self-renew and migration of urine-derived stem cells by upregulating autophagy and mitochondrial function through ERK signal pathway

Urine-derived stem cells (USCs) are autologous stem cells with self-renewal ability and multi-lineage differentiation potential. Our previous studies have shown that hypoxia preconditioning can improve self-renewal and migration abilities of USCs by up-regulating autophagy. The purpose of this study was to investigate the specific mechanism by which hypoxia treatment promotes the biological function of USCs. We found that hypoxia treatment upregulated the expression of phosphralated ERK protein without affecting the expression of total ERK protein. Inhibiting ERK signaling with the PD98059 inhibitor decreased cell proliferation, migration and colony formation during hypoxia treatment. Hypoxia increased ATP production, mitochondrial membrane potential and mt-DNA copy number, which were reversed by inhibiting the ERK signal. Additionally, the number of autophagosomes and autophagic lysosomes was significantly lower in PD98059 group than in the hypoxia group. PD98059 treatment inhibited the up-regulation of autophagy related proteins induced by hypoxia. Therefore, this study suggests that hypoxia improves the self-renewal and migration abilities of USCs by upregulating autophagy and mitochondrial function through ERK signaling pathway. This finding may provide a new therapeutic mechanism for hypoxia pretreated USCs as a source of stem cell transplantation.

Morroniside inhibits Beclin1-dependent autophagic death and Bax-dependent apoptosis in cardiomyocytes through repressing BCL2 phosphorylation

Morroniside can prevent myocardial injury caused by ischemia and hypoxia, which can be used to treat acute myocardial infarction (AMI). Hypoxia can cause apoptosis and autophagic death of cardiomyocytes. Morroniside has the ability to inhibit apoptosis and autophagy. However, the relationship between Morroniside-protected cardiomyocytes and two forms of death is unclear. The effects of Morroniside on the proliferation, apoptosis level, and autophagic activity of rat cardiomyocyte line H9c2 under hypoxia were first observed. Next, the roles of Morroniside in the phosphorylation of JNK and BCL2, BCL2-Beclin1, and BCL2-Bax complexes as well as mitochondrial membrane potential in H9c2 cells were evaluated upon hypoxia. Finally, the significance of BCL2 or JNK in Morroniside-regulated autophagy, apoptosis, and proliferation in H9c2 cells was assessed by combining Morroniside and BCL2 competitive inhibitor (ABT-737) or JNK activator (Anisomycin). Our results showed that hypoxia promoted autophagy and apoptosis of H9c2 cells, and inhibited their proliferation. However, Morroniside could block the effect of hypoxia on H9c2 cells. In addition, Morroniside could inhibit JNK phosphorylation, BCL2 phosphorylation at the Ser70 and Ser87 sites, and the dissociation of BCL2-Beclin1 and BCL2-Bax complexes in H9c2 cells upon hypoxia. Moreover, the reduction of mitochondrial membrane potential in H9c2 cells caused by hypoxia was improved by Morroniside administration. Importantly, the inhibited autophagy, apoptosis, and promoted proliferation in H9c2 cells by Morroniside were reversed by the application of ABT-737 or Anisomycin. Overall, Morroniside inhibits Beclin1-dependent autophagic death and Bax-dependent apoptosis via JNK-mediated BCL2 phosphorylation, thereby improving the survival of cardiomyocytes under hypoxia.

The topoisomerase inhibitor CPT-11 prevents the growth and metastasis of lung cancer cells in nude mice by inhibiting EGFR/MAPK signaling pathway

Objective

The topoisomerase inhibitor CPT-11 has been applied in treatment of multiple cancer types. Here, we probed into the possible mechanism of CPT-11 in affecting growth and metastasis of lung cancer (LC) cells, with involvement of the EGFR/MAPK pathway.

Methods

The target protein of CPT-11 was screened through bioinformatics analysis, and the LC-related microarray datasets GSE29249, GSE32863 and GSE44077 were obtained for differential analysis for identifying the target protein. A subcutaneous xenograft tumor model and a metastatic tumor model were constructed in nude mice for in vivo mechanism verification of the regulatory role of CPT-11 in LC through modulation of EGRF/MAPK pathway.

Results

Bioinformatics analysis showed that EGFR was the target protein of CPT-11. In vivo animal experiments confirmed that CPT-11 enhanced LC cell growth and metastasis in nude mice. CPT-11 could inhibit activation of EGFR/MAPK pathway. EGFR promoted LC cell growth and metastasis in nude mice through activation of the MAPK pathway.

Conclusion

The topoisomerase inhibitor CPT-11 may prevent LC growth and metastasis by inhibiting activation of EGFR/MAPK pathway.

The Clinical Application of Immunohistochemical Expression of Notch4 Protein in Patients with Colon Adenocarcinoma

The Notch signalling pathway is one of the most conserved and well-characterised pathways involved in cell fate decisions and the development of many diseases, including cancer. Among them, it is worth noting the Notch4 receptor and its clinical application, which may have prognostic value in patients with colon adenocarcinoma. The study was performed on 129 colon adenocarcinomas. Immunohistochemical and fluorescence expression of Notch4 was performed using the Notch4 antibody. The associations between the IHC expression of Notch4 and clinical parameters were analysed using the Chi² test or Chi²_Yatesa test. The Kaplan-Meier analysis and the log-rank test were used to verify the relationship between the intensity of Notch4 expression and the 5-year survival rate of patients. Intracellular localisation of Notch4 was detected by the use of the immunogold labelling method and TEM. 101 (78.29%) samples had strong Notch4 protein expression, and 28 (21.71%) samples were characterised by low expression. The high expression of Notch4 was clearly correlated with the histological grade of the tumour (p < 0.001), PCNA immunohistochemical expression (p < 0.001), depth of invasion (p < 0.001) and angioinvasion (p < 0.001). We can conclude that high expression of Notch4 is correlated with poor prognosis of colon adenocarcinoma patients (log-rank, p < 0.001).

Notch signaling, hypoxia, and cancer

Notch signaling is involved in cell fate determination and deregulated in human solid tumors. Hypoxia is an important feature in many solid tumors, which activates hypoxia-induced factors (HIFs) and their downstream targets to promote tumorigenesis and cancer development. Recently, HIFs have been shown to trigger the Notch signaling pathway in a variety of organisms and tissues. In this review, we focus on the pro- and anti-tumorigenic functions of Notch signaling and discuss the crosstalk between Notch signaling and cellular hypoxic response in cancer pathogenesis, including epithelia-mesenchymal transition, angiogenesis, and the maintenance of cancer stem cells. The pharmacological strategies targeting Notch signaling and hypoxia in cancer are also discussed in this review.

SET/PP2A signaling regulates macrophage positioning in hypoxic tumor regions by amplifying chemotactic responses

Tumor-associated macrophages (TAMs) are one of the main cellular components in the tumor microenvironment (TME). In many types of solid tumors, TAMs tend to accumulate in hypoxic areas and are intimately related to poor patient prognosis. However, the underlying mechanisms by which TAMs infiltrate hypoxic tumor regions remain unclear. In this study, we report that genetic deletion of SE translocation (SET) in myeloid cells inhibited the entry of TAMs into the hypoxic tumor region and abated their proangiogenic and immunosuppressive functions, ultimately inhibiting tumor growth. Mechanistically, in response to hypoxic tumor supernatant stimulation, SET in macrophages shuttled between the nucleus and cytoplasm via the PKC-CK2α signaling axis. Cytoplasmic retention of SET increased ERK and P38 signaling by inhibiting PP2A, which promoted TAM migration into the hypoxic area and polarization toward the M2 phenotype. Therefore, we conclude that SET modulates tumor immunity by acting as a key regulator of macrophage positioning and function in the tumor.