CIP2A overexpression induces autoimmune response and enhances JNK signaling pathway in human lung cancer

The role of programmed cell death in osteosarcoma: From pathogenesis to therapy

Osteosarcoma (OS) is a prevalent bone solid malignancy that primarily affects adolescents, particularly boys aged 14-19. This aggressive form of cancer often leads to deadly lung cancer due to its high migration ability. Experimental evidence suggests that programmed cell death (PCD) plays a crucial role in the development of osteosarcoma. Various forms of PCD, including apoptosis, ferroptosis, autophagy, necroptosis, and pyroptosis, contribute significantly to the progression of osteosarcoma. Additionally, different signaling pathways such as STAT3/c-Myc signal pathway, JNK signl pathway, PI3k/AKT/mTOR signal pathway, WNT/β-catenin signal pathway, and RhoA signal pathway can influence the development of osteosarcoma by regulating PCD in osteosarcoma cell. Therefore, targeting PCD and the associated signaling pathways could offer a promising therapeutic approach for treating osteosarcoma.

Evaluation of novel pyrazol-4-yl pyridine derivatives possessing arylsulfonamide tethers as c-Jun N-terminal kinase (JNK) inhibitors in leukemia cells

A series of 36 pyrazol-4-yl pyridine derivatives (8a-i, 9a-i, 10a-i, and 11a-i) was designed, synthesized, and evaluated for its antiproliferative activity over NCI-60 cancer cell line panel and inhibitory effect against JNK isoforms (JNK1, JNK2, and JNK3). All the synthesized compounds were tested against the NCI-60 cancer cell line panel. Compounds 11b, 11c, 11g, and 11i were selected to determine their GI50s and exerted a superior potency over the reference standard SP600125 against the tested cell lines. 11c showed a GI50 of 1.28 μM against K562 leukemic cells. Vero cells were used to assess 11c cytotoxicity compared to the tested cancer cells. The target compounds were tested against hJNK isoforms in which compound 11e exhibited the highest potency against JNK isoforms with IC50 values of 1.81, 12.7, and 10.5 nM against JNK1, JNK2, and JNK3, respectively. Kinase profiling of 11e showed higher JNK selectivity in 50 kinase panels. Compounds 11c and 11e showed cell population arrest at the G2/M phase, induced early apoptosis, and slightly inhibited beclin-1 production at higher concentrations in K562 leukemia cells relative to SP600125. NanoBRET assay of 11e showed intracellular JNK1 inhibition with an IC50 of 2.81 μM. Also, it inhibited CYP2D6 and 3A4 with different extent and its hERG activity showed little cardiac toxicity with an IC50 of 4.82 μM. hJNK3 was used as a template to generate the hJNK1 crystal structure to explore the binding mode of 11e (PDB ID: 8ENJ) with a resolution of 2.8 °A and showed a typical type I kinase inhibition against hJNK1. Binding energy scores showed that selectivity of 11e towards JNK1 could be attributed to additional hydrophobic interactions relative to JNK3.

Regulation and role of the PP2A-B56 holoenzyme family in cancer

Protein phosphatase 2A (PP2A) inactivation is common in cancer, leading to sustained activation of pro-survival and growth-promoting pathways. PP2A consists of a scaffolding A-subunit, a catalytic C-subunit, and a regulatory B-subunit. The functional complexity of PP2A holoenzymes arises mainly through the vast repertoire of regulatory B-subunits, which determine both their substrate specificity and their subcellular localization. Therefore, a major challenge for developing more effective therapeutic strategies for cancer is to identify the specific PP2A complexes to be targeted. Of note, the development of small molecules specifically directed at PP2A-B56α has opened new therapeutic avenues in both solid and hematological tumors. Here, we focus on the B56/PR61 family of PP2A regulatory subunits, which have a central role in directing PP2A tumor suppressor activity. We provide an overview of the mechanisms controlling the formation and regulation of these complexes, the pathways they control, and the mechanisms underlying their deregulation in cancer.

Protein Phosphatase 2A as a Therapeutic Target in Pulmonary Diseases

New disease targets and medicinal chemistry approaches are urgently needed to develop novel therapeutic strategies for treating pulmonary diseases. Emerging evidence suggests that reduced activity of protein phosphatase 2A (PP2A), a complex heterotrimeric enzyme that regulates dephosphorylation of serine and threonine residues from many proteins, is observed in multiple pulmonary diseases, including lung cancer, smoke-induced chronic obstructive pulmonary disease, alpha-1 antitrypsin deficiency, asthma, and idiopathic pulmonary fibrosis. Loss of PP2A responses is linked to many mechanisms associated with disease progressions, such as senescence, proliferation, inflammation, corticosteroid resistance, enhanced protease responses, and mRNA stability. Therefore, chemical restoration of PP2A may represent a novel treatment for these diseases. This review outlines the potential impact of reduced PP2A activity in pulmonary diseases, endogenous and exogenous inhibitors of PP2A, details the possible PP2A-dependent mechanisms observed in these conditions, and outlines potential therapeutic strategies for treatment. Substantial medicinal chemistry efforts are underway to develop therapeutics targeting PP2A activity. The development of specific activators of PP2A that selectively target PP2A holoenzymes could improve our understanding of the function of PP2A in pulmonary diseases. This may lead to the development of therapeutics for restoring normal PP2A responses within the lung.

From Basic Science to Clinical Practice: The Role of Cancerous Inhibitor of Protein Phosphatase 2A (CIP2A)/p90 in Cancer

Cancerous inhibitor of protein phosphatase 2A (CIP2A), initially reported as a tumor-associated antigen (known as p90), is highly expressed in most solid and hematological tumors. The interaction of CIP2A/p90, protein phosphatase 2A (PP2A), and c-Myc can hinder the function of PP2A toward c-Myc S62 induction, thus stabilizing c-Myc protein, which represents a potential role of CIP2A/p90 in tumorigeneses such as cell proliferation, invasion, and migration, as well as cancer drug resistance. The signaling pathways and regulation networks of CIP2A/p90 are complex and not yet fully understood. Many previous studies have also demonstrated that CIP2A/p90 can be used as a potential therapeutic cancer target. In addition, the autoantibody against CIP2A/p90 in sera may be used as a promising biomarker in the diagnosis of certain types of cancer. In this Review, we focus on recent advances relating to CIP2A/p90 and their implications for future research.

Unraveling the Design and Discovery of c-Jun N-Terminal Kinase Inhibitors and Their Therapeutic Potential in Human Diseases

c-Jun N-terminal kinases (JNKs), members of the mitogen-activated protein kinase (MAPK) family, are encoded by three genes: jnk1, jnk2, and jnk3. JNKs are involved in the pathogenesis and development of many diseases, such as neurodegenerative diseases, inflammation, and cancers. Therefore, JNKs have become important therapeutic targets. Many JNK inhibitors have been discovered, and some have been introduced into clinical trials. However, the study of isoform-selective JNK inhibitors is still a challenging task. To further develop novel JNK inhibitors with clinical value, a comprehensive understanding of JNKs and their corresponding inhibitors is required. In this Perspective, we introduced the JNK signaling pathways and reviewed different chemical types of JNK inhibitors, focusing on their structure-activity relationships and biological activities. The challenges and strategies for the development of JNK inhibitors are also discussed. It is hoped that this Perspective will provide valuable references for the development of novel selective JNK inhibitors.

POU2F1 induces the immune escape in lung cancer by up-regulating PD-L1

PURPOSE

The aim was to research the POU2F1 related genes and mechanism during the progress of immune escape of lung cancer.

METHODS

Lung cancer cell lines (H1993, HCC827, A549, H2228, H3122 and H1975) and Human normal lung epithelial cell line (BEAS-2B) were involved in this study. Overexpression or knockdown of POU2F1 was processed in lung cancer cells. POU2F1, PD-L1 and CRK expression in cells were detected by WB and RT-PCR. Flow cytometry and immunofluorescence was used to detect PD-L1 expression on the cell surface. Luciferase reporter detected the promoter activity of CRK. C57BL/6 mice models with knocked down of of POU2F1 were constructed. After tumor formation, anti-PD-1 was administered to detect tumor suppressing ability. IHC assay showed the number of intratumoral CD3+, CD8+, GranzB+ T cells.

RESULTS

POU2F1 and PD-L1 were positively correlated in lung cancer cell lines. Overexpression of POU2F1 promoted the expression level of PD-L1 in lung cancer cells. POU2F1 transcription activated the expression of CRK, and further promoted the expression of PD-L1. Knockdown of POU2F1 promoted the efficacy of Anti-PD-1. In addition, tumor growth ability decreased after POU2F1 was knocked down. Cytotoxic effector cytokines levels, tumor suppressive chemokines and interleukin increased, while IL17a level decreased when POU2F1 was knocked down.

CONCLUSION

POU2F1 activates the expression of CRK, further promotes the expression of PD-L1, and finally improves the immune escape in lung cancer.

A spirostanol saponin isolated from Tupistra chinensis Baker simultaneously induces apoptosis and autophagy by regulating the JNK pathway in human gastric cancer cells

T-17, a bioactive spirostanol saponin extracted from Tupistra chinensis Baker, was previously reported with anti-inflammatory and cytotoxic activities. However, the mechanism underlying of its anti-proliferation activity remains to be elucidated. In this study, we investigated the anti-gastric cancer cell growth activity of T-17 in terms of cell viability, colony formation, cell cycle, induction of apoptosis/autophagy, and JNK pathway. T-17 showed dose-dependent cytotoxicity in SGC-7901 and AGS cell lines, it induced caspase-mediated apoptosis as well as G0/G1 phase arrest and modulation of cyclinE2 and p21 expression. In addition, T-17 promoted the cancer cell autophagy as evidenced with increased expression of Beclin-1 and decreased p62 in western blot and formation of GFP-LC3 puncta. Furthermore, T-17-induced autophagy decreased gastric cancer cell apoptosis as assessed by pharmacological autophagy inhibitors and ATG5 siRNA usage. Importantly, the activation of JNK pathway was simultaneously involved in T-17-induced apoptosis and autophagy. Taken together, the results suggest that T-17 is a promising cytotoxic agent for therapeutic treatment of human gastric adenocarcinoma, which provides a good foundation for further research and development of Tupistra chinensis Baker.

Selective inhibitors for JNK signalling: a potential targeted therapy in cancer

c-Jun N-terminal kinase (JNK) signalling regulates both cancer cell apoptosis and survival. Emerging evidence show that JNK promoted tumour progression is involved in various cancers, that include human pancreatic-, lung-, and breast cancer. The pro-survival JNK oncoprotein functions in a cell context- and cell type-specific manner to affect signal pathways that modulate tumour initiation, proliferation, and migration. JNK is therefore considered a potential oncogenic target for cancer therapy. Currently, designing effective and specific JNK inhibitors is an active area in the cancer treatment. Some ATP-competitive inhibitors of JNK, such as SP600125 and AS601245, are widely used in vitro; however, this type of inhibitor lacks specificity as they indiscriminately inhibit phosphorylation of all JNK substrates. Moreover, JNK has at least three isoforms with different functions in cancer development and identifying specific selective inhibitors is crucial for the development of targeted therapy in cancer. Some selective inhibitors of JNK are identified; however, their clinical studies in cancer are relatively less conducted. In this review, we first summarised the function of JNK signalling in cancer progression; there is a focus on the discussion of the novel selective JNK inhibitors as potential targeting therapy in cancer. Finally, we have offered a future perspective of the selective JNK inhibitors in the context of cancer therapies. We hope this review will help to further understand the role of JNK in cancer progression and provide insight into the design of novel selective JNK inhibitors in cancer treatment.

Protein phosphatase 2A (PP2A): a key phosphatase in the progression of chronic obstructive pulmonary disease (COPD) to lung cancer

Lung cancer (LC) has the highest relative risk of development as a comorbidity of chronic obstructive pulmonary disease (COPD). The molecular mechanisms that mediate chronic inflammation and lung function impairment in COPD have been identified in LC. This suggests the two diseases are more linked than once thought. Emerging data in relation to a key phosphatase, protein phosphatase 2A (PP2A), and its regulatory role in inflammatory and tumour suppression in both disease settings suggests that it may be critical in the progression of COPD to LC. In this review, we uncover the importance of the functional and active PP2A holoenzyme in the context of both diseases. We describe PP2A inactivation via direct and indirect means and explore the actions of two key PP2A endogenous inhibitors, cancerous inhibitor of PP2A (CIP2A) and inhibitor 2 of PP2A (SET), and the role they play in COPD and LC. We explain how dysregulation of PP2A in COPD creates a favourable inflammatory micro-environment and promotes the initiation and progression of tumour pathogenesis. Finally, we highlight PP2A as a druggable target in the treatment of COPD and LC and demonstrate the potential of PP2A re-activation as a strategy to halt COPD disease progression to LC. Although further studies are required to elucidate if PP2A activity in COPD is a causal link for LC progression, studies focused on the potential of PP2A reactivating agents to reduce the risk of LC formation in COPD patients will be pivotal in improving clinical outcomes for both COPD and LC patients in the future.

JNK signaling in cancer cell survival

c-Jun N-terminal kinase (JNK) is involved in cancer cell apoptosis; however, emerging evidence indicates that this Janus signaling promotes cancer cell survival. JNK acts synergistically with NF-κB, JAK/STAT, and other signaling molecules to exert a survival function. JNK positively regulates autophagy to counteract apoptosis, and its effect on autophagy is related to the development of chemotherapeutic resistance. The prosurvival effect of JNK may involve an immune evasion mechanism mediated by transforming growth factor-β, toll-like receptors, interferon-γ, and autophagy, as well as compensatory JNK-dependent cell proliferation. The present review focuses on recent advances in understanding the prosurvival function of JNK and its role in tumor development and chemoresistance, including a comprehensive analysis of the molecular mechanisms underlying JNK-mediated cancer cell survival. There is a focus on the specific "Yin and Yang" functions of JNK1 and JNK2 in the regulation of cancer cell survival. We highlight recent advances in our knowledge of the roles of JNK in cancer cell survival, which may provide insight into the distinct functions of JNK in cancer and its potential for cancer therapy.

PI3K-PKB-mTOR hyperactivation in relation to nasopharyngeal carcinoma progression and prognosis

Nasopharyngeal carcinoma (NPC) has a unique and complex etiology, which is not completely understood. The aim of this study is to investigate the expression patterns of phosphatidylinositol 3-kinase (PI3K), protein kinase B (PKB), and mammalian target of rapamycin (mTOR) proteins in patients with NPC and their relationship with NPC progression and prognosis. Between January 2008 and March 2010, PI3K, PKB, and mTOR protein expressions were detected using immunohistochemistry among 119 patients with NPC and 30 healthy people. A 5-year follow-up was conducted for all patients. Correlations of PI3K, PKB, and mTOR proteins with the clinicopathological features and prognosis of NPC were evaluated using Spearman's rank correlation coefficient and Kaplan-Meier curve. Cox's regression analysis was performed to analyze the risk factors for the prognosis of NPC. First, PI3K, PKB, and mTOR were highly expressed in patients with NPC. The expressions of PI3K, PKB, and mTOR proteins were associated with T stage, N stage, clinical stage, relapse, and distant metastasis. Meanwhile, PI3K is positively correlated with PKB and PKB is positively correlated with mTOR in NPC. Higher PI3K, PKB, and mTOR protein expressions were related to a shorter survival time and a lower survival rate in NPC. Cox regression analysis revealed that age, T stage, N stage, PI3K, PKB, and mTOR were independent risk factors for NPC patient survival. Altogether, our data suggest that overexpression of PI3K, PKB, and mTOR proteins is an important indicator of poor survival in NPC. In addition, inhibition of PI3K-PKB-mTOR signaling may also contribute to the development of new therapeutic strategies for NPC.

Prognostic significance of CIP2A expression in solid tumors: A meta-analysis

CIP2A, cancerous inhibitor of protein phosphatase 2A, was initially recognized as an oncoprotein. Recently several studies revealed that CIP2A could function as a prognosis biomarker, however, the result remained not comprehensive, partly due to small number of patients included individually. Here we carried out a meta-analysis of published studies to assess the prognostic significance of CIP2A in solid tumors. All eligible studies were identified through searching PubMed, Embase and Web of Science database. In this meta-analysis, 22 studies involving 4,579 participants were included, and we verified that CIP2A over-expression was significantly related with poor overall survival (pooled HR = 1.844, 95% CI = 1.528–2.225, P<0.001) and short disease free survival (pooled HR = 1.808, 95% CI = 1.591–2.055, P<0.001) in solid tumors. Additionally, subgroup analysis suggested that the trend of a poor overall survival with an increased CIP2A expression was present in East-Asian and European patients, as well as in lung cancer and colorectal cancer. To sum up, CIP2A over-expression was associated with poor survival in human solid tumors and might be a predictive factor of poor prognosis.

CIP2A acts as a scaffold for CEP192-mediated microtubule organizing center assembly by recruiting Plk1 and aurora A during meiotic maturation

In somatic cells spindle microtubules are nucleated from centrosomes that act as major microtubule organizing centers (MTOCs), whereas oocytes form meiotic spindles by assembling multiple acentriolar MTOCs without canonical centrosomes. Aurora A and Plk1 are required for these events, but the underlying mechanisms remain largely unknown. Here we show that CIP2A regulates MTOC organization by recruiting aurora A and Plk1 at spindle poles during meiotic maturation. CIP2A colocalized with pericentrin at spindle poles with a few distinct cytoplasmic foci. Although CIP2A has been identified as an endogenous inhibitor of protein phosphatase 2A (PP2A), overexpression of CIP2A had no effect on meiotic maturation. Depletion of CIP2A perturbed normal spindle organization and chromosome alignment by impairing MTOC organization. Importantly, CIP2A was reciprocally associated with CEP192, promoting recruitment of aurora A and Plk1 at MTOCs. CIP2A was phosphorylated by Plk1 at S904, which targets CIP2A to MTOCs and facilitates MTOC organization with CEP192. Our results suggest that CIP2A acts as a scaffold for CEP192-mediated MTOC assembly by recruiting Plk1 and aurora A during meiotic maturation in mouse oocytes.