Dioscin overcome TKI resistance in EGFR-mutated lung adenocarcinoma cells via down-regulation of tyrosine phosphatase SHP2 expression

IL-22: A key inflammatory mediator as a biomarker and potential therapeutic target for lung cancer

Lung cancer, one of the most prevalent cancers worldwide, stands as the primary cause of cancer-related deaths. As is well-known, the utmost crucial risk factor contributing to lung cancer is smoking. In recent years, remarkable progress has been made in treating lung cancer, particularly non-small cell lung cancer (NSCLC). Nevertheless, the absence of effective and accurate biomarkers for diagnosing and treating lung cancer remains a pressing issue. Interleukin 22 (IL-22) is a member of the IL-10 cytokine family. It exerts biological functions (including induction of proliferation and anti-apoptotic signaling pathways, enhancement of tissue regeneration and immunity defense) by binding to heterodimeric receptors containing type 1 receptor chain (R1) and type 2 receptor chain (R2). IL-22 has been identified as a pro-cancer factor since dysregulation of the IL-22-IL-22R system has been implicated in the development of different cancers, including lung, breast, gastric, pancreatic, and colon cancers. In this review, we discuss the differential expression, regulatory role, and potential clinical significance of IL-22 in lung cancer, while shedding light on innovative approaches for the future.

Inhibiting H2AX Can Ameliorate Myocardial Ischemia/Reperfusion Injury by Regulating P53/JNK Signaling Pathway

Myocardial ischemia-reperfusion (I/R) injury is a significant area of focus in cardiovascular disease research. I/R injury can increase intracellular oxidative stress, leading to DNA damage. H2AX plays a crucial role in DNA repair. This study utilized mouse and cell models of myocardial I/R to investigate the impact of H2AX on cardiomyocytes during I/R. This study initially assessed the expression of H2AX in MI/R mice compared to a sham surgery group. Subsequently, cardiac function, infarct area, and mitochondrial damage were evaluated after inhibiting H2AX in MI/R mice and a negative control group. Furthermore, the study delved into the molecular mechanisms by analyzing the expression of H2AX, P53, p-JNK, SHP2, p-SHP2, p-RAS, parkin, Drp1, Cyt-C, Caspase-3, and Caspase-8 in cardiomyocytes following the addition of JNK or P53 agonists. The results from western blotting in vivo indicated significantly higher H2AX expression in the MI/R group compared to the sham group. Inhibiting H2AX improved cardiac function, reduced myocardial infarct area, and mitigated mitochondrial damage in the MI/R group. In vitro experiments demonstrated that inhibiting H2AX could attenuate mitochondrial damage and apoptosis in myocardial cells by modulating the P53 and JNK signaling pathways. These findings suggested that inhibiting H2AX may alleviate myocardial I/R injury through the regulation of the P53/JNK pathway, highlighting H2AX as a potential target for the treatment of myocardial ischemia/reperfusion injury.

Advances in antitumor activity and mechanism of natural steroidal saponins: A review of advances, challenges, and future prospects

BACKGROUND

Cancer, the second leading cause of death worldwide following cardiovascular diseases, presents a formidable challenge in clinical settings due to the extensive toxic side effects associated with primary chemotherapy drugs employed for cancer treatment. Furthermore, the emergence of drug resistance against specific chemotherapeutic agents has further complicated the situation. Consequently, there exists an urgent imperative to investigate novel anticancer drugs. Steroidal saponins, a class of natural compounds, have demonstrated notable antitumor efficacy. Nonetheless, their translation into clinical applications has remained unrealized thus far. In light of this, we conducted a comprehensive systematic review elucidating the antitumor activity, underlying mechanisms, and inherent limitations of steroidal saponins. Additionally, we propose a series of strategic approaches and recommendations to augment the antitumor potential of steroidal saponin compounds, thereby offering prospective insights for their eventual clinical implementation.

PURPOSE

This review summarizes steroidal saponins' antitumor activity, mechanisms, and limitations.

METHODS

The data included in this review are sourced from authoritative databases such as PubMed, Web of Science, ScienceDirect, and others.

RESULTS

A comprehensive summary of over 40 steroidal saponin compounds with proven antitumor activity, including their applicable tumor types and structural characteristics, has been compiled. These steroidal saponins can be primarily classified into five categories: spirostanol, isospirostanol, furostanol, steroidal alkaloids, and cholestanol. The isospirostanol and cholestanol saponins are found to have more potent antitumor activity. The primary antitumor mechanisms of these saponins include tumor cell apoptosis, autophagy induction, inhibition of tumor migration, overcoming drug resistance, and cell cycle arrest. However, steroidal saponins have limitations, such as higher cytotoxicity and lower bioavailability. Furthermore, strategies to address these drawbacks have been proposed.

CONCLUSION

In summary, isospirostanol and cholestanol steroidal saponins demonstrate notable antitumor activity and different structural categories of steroidal saponins exhibit variations in their antitumor signaling pathways. However, the clinical application of steroidal saponins in cancer treatment still faces limitations, and further research and development are necessary to advance their potential in tumor therapy.

Setting sail: Maneuvering SHP2 activity and its effects in cancer

Since the discovery of tyrosine phosphorylation being a critical modulator of cancer signaling, proteins regulating phosphotyrosine levels in cells have fast become targets of therapeutic intervention. The nonreceptor protein tyrosine phosphatase (PTP) coded by the PTPN11 gene "SHP2" integrates phosphotyrosine signaling from growth factor receptors into the RAS/RAF/ERK pathway and is centrally positioned in processes regulating cell development and oncogenic transformation. Dysregulation of SHP2 expression or activity is linked to tumorigenesis and developmental defects. Even as a compelling anti-cancer target, SHP2 was considered "undruggable" for a long time owing to its conserved catalytic PTP domain that evaded drug development. Recently, SHP2 has risen from the "undruggable curse" with the discovery of small molecules that manipulate its intrinsic allostery for effective inhibition. SHP2's unique domain arrangement and conformation(s) allow for a truly novel paradigm of inhibitor development relying on skillful targeting of noncatalytic sites on proteins. In this review we summarize the biological functions, signaling properties, structural attributes, allostery and inhibitors of SHP2.

A novel mitochondria-related gene signature in esophageal carcinoma: prognostic, immune, and therapeutic features

Esophageal carcinoma (ESCA) is a common and lethal malignant tumor worldwide. The mitochondrial biomarkers were useful in finding significant prognostic gene modules associated with ESCA owing to the role of mitochondria in tumorigenesis and progression. In the present work, we obtained the transcriptome expression profiles and corresponding clinical information of ESCA from The Cancer Genome Atlas (TCGA) database. Differential expressed genes (DEGs) were overlapped with 2030 mitochondria-related genes to get mitochondria-related DEGs. The univariate cox regression, Least Absolute Shrinkage and Selection Operator (LASSO) regression, and multivariate cox regression were sequentially used to define the risk scoring model for mitochondria-related DEGs, and its prognostic value was verified in the external datasets GSE53624. Based on the risk score, ESCA patients were divided into high- and low-risk groups. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Set Enrichment Analysis (GSEA) were performed to further investigate the difference between low- and high-risk groups at the gene pathway level. CIBERSORT was used to evaluate immune cell infiltration. The mutation difference between high- and low-risk groups was compared by using the R package "Maftools". Cellminer was used to assess the association between the risk scoring model and drug sensitivity. As the most important outcome of the study, a 6-gene risk scoring model (APOOL, HIGD1A, MAOB, BCAP31, SLC44A2, and CHPT1) was constructed from 306 mitochondria-related DEGs. Pathways including the "hippo signaling pathway" and "cell-cell junction" were enriched in the DEGs between high and low groups. According to CIBERSORT, samples with high-risk scores demonstrated a higher abundance of CD4⁺ T cells, NK cells, M0 and M2 macrophages, and a lower abundance of M1 macrophages. The immune cell marker genes were correlated with the risk score. In mutation analysis, the mutation rate of TP53 was significantly different between the high- and low-risk groups. Drugs with a strong correlation with the risk model were selected. In conclusion, we focused on the role of mitochondria-related genes in cancer development and proposed a prognostic signature for individualized integrative assessment.

A comprehensive review of SHP2 and its role in cancer

Src homology 2-containing protein tyrosine phosphatase 2 (SHP2) is a non-receptor protein tyrosine phosphatase ubiquitously expressed mainly in the cytoplasm of several tissues. SHP2 modulates diverse cell signaling events that control metabolism, cell growth, differentiation, cell migration, transcription and oncogenic transformation. It interacts with diverse molecules in the cell, and regulates key signaling events including RAS/ERK, PI3K/AKT, JAK/STAT and PD-1 pathways downstream of several receptor tyrosine kinases (RTKs) upon stimulation by growth factors and cytokines. SHP2 acts as both a phosphatase and a scaffold, and plays prominently oncogenic functions but can be tumor suppressor in a context-dependent manner. It typically acts as a positive regulator of RTKs signaling with some inhibitory functions reported as well. SHP2 expression and activity is regulated by such factors as allosteric autoinhibition, microRNAs, ubiquitination and SUMOylation. Dysregulation of SHP2 expression or activity causes many developmental diseases, and hematological and solid tumors. Moreover, upregulated SHP2 expression or activity also decreases sensitivity of cancer cells to anticancer drugs. SHP2 is now considered as a compelling anticancer drug target and several classes of SHP2 inhibitors with different mode of action are developed with some already in clinical trial phases. Moreover, novel SHP2 substrates and functions are rapidly growing both in cell and cancer. In view of this, we comprehensively and thoroughly reviewed literatures about SHP2 regulatory mechanisms, substrates and binding partners, biological functions, roles in human cancers, and different classes of small molecule inhibitors target this oncoprotein in cancer.

Developments in the Antitumor Activity, Mechanisms of Action, Structural Modifications, and Structure-Activity Relationships of Steroidal Saponins

Steroidal saponins, a class of natural products formed by the combination of spirosteranes with sugars, are widely distributed in plants and have various biological activities, such as anti-tumor, anti-inflammatory, anti-bacterial, anti-Alzheimer's, anti-oxidation, etc. Particularly, extensive researches on the antitumor property of steroidal saponins have been received. Steroidal sapogenins, the aglycones of steroidal saponins, also have attracted much attention due to a vast range of pharmacological activities similar to steroidal saponins. In the past few years, structural modifications on the aglycones and sugar chains of steroidal saponins have been carried out and some achievements have been made. In this mini-review, the antitumor activity, action mechanisms, and structural modifications along with the structure-activity relationships of steroidal saponins and their derivatives are summarized.

Medicinal herbs and bioactive compounds overcome the drug resistance to epidermal growth factor receptor inhibitors in non-small cell lung cancer

Lung cancer is the leading cause of cancer-related mortality worldwide. Non-small cell lung cancer (NSCLC) accounts for ~85% of all lung cancer cases. Patients harboring epidermal growth factor receptor (EGFR) mutations usually develop resistance to treatment with frontline EGFR-tyrosine kinase inhibitors (EGFR-TKIs). The present review summarizes the current findings and delineates the molecular mechanism of action for the therapeutic effects of herbal extracts and phytochemicals in overcoming EGFR-TKI resistance in NSCLC. Novel molecular targets underlying EGFR-TKI resistance in NSCLC are also discussed. This review provides valuable information for the development of herbal bioactive compounds as alternative treatments for EGFR-TKI-resistant NSCLC.

Diosgenin attenuates tumor growth and metastasis in transgenic prostate cancer mouse model by negatively regulating both NF-κB/STAT3 signaling cascades

Prostate cancer (PCa) is a common disease among men especially in the old age. The deregulated activation of oncogenic and pro-survival transcription factors has been linked with tumor progression in PCa patients. The consequence of diosgenin treatment on NF-κB/STAT3 activation in PCa cells as well as transgenic mouse model was determined. We also validated the hypothesis of targeting these transcription factors using in silico proteomics simulation model. Diosgenin abrogated NF-κB/STAT3 activation and this action was caused as a result of suppression of protein kinases and reporter gene activity that led to a substantial reduction in the expression of various tumorigenic gene products. In vivo, diosgenin (2% w/w) when mixed in diet and fed to mice abrogated tumor progression in transgenic mice. Diosgenin was also detected in serum and was well absorbed orally. Overall, our data highlights the promising efficacy of diosgenin in PCa therapy.

Characteristics of the PI3K/AKT and MAPK/ERK pathways involved in the maintenance of self-renewal in lung cancer stem-like cells

Lung cancer is the leading cause of cancer-related mortality worldwide due to its early asymptomatic and late metastasis. While cancer stem cells (CSCs) may play a vital role in oncogenesis and development of lung cancer, mechanisms underlying CSCs self-renewal remain less clear. In the present study, we constructed a clinically relevant CSCs enrichment recognition model and evaluated the potential functions of phosphatidylinositol 3-kinase (PI3K)/AKT pathway (PI3K/AKT) and mitogen-activated protein kinases/extracellular signal-regulated kinase (MAPK/ERK) pathways in lung cancer via bioinformatic analysis, providing the basis for in depth mechanistic inquisition. Experimentally, we confirmed that PI3K/AKT pathway predominantly promotes proliferation through anti-apoptosis in lung adenocarcinoma cells, while MAPK/ERK pathway has an overwhelming superiority in regulating the proliferation in lung CSCs. Further, utilizing stemness score model, LLC-Symmetric Division (LLC-SD) cells and mouse orthotopic lung transplantation model, we elucidated an intricate cross-talk between the oncogenic pathway and the stem cell reprograming pathway that impact stem cell characteristics as well as cancer biology features of lung CSCs both in vitro and in vivo. In summary, our findings uncovered a new insight that PI3K/AKT and MAPK/ERK pathways as oncogenic signaling pathway and/or stem cell signaling pathway act distinctively and synergistically to regulate lung CSCs self-renewal.

Activating Mutation of SHP2 Establishes a Tumorigenic Phonotype Through Cell-Autonomous and Non-Cell-Autonomous Mechanisms

Gain-of-function mutation of SHP2 is a central regulator in tumorigenesis and cancer progression through cell-autonomous mechanisms. Activating mutation of SHP2 in microenvironment was identified to promote cancerous transformation of hematopoietic stem cell in non-autonomous mechanisms. It is interesting to see whether therapies directed against SHP2 in tumor or microenvironmental cells augment antitumor efficacy. In this review, we summarized different types of gain-of-function SHP2 mutations from a human disease. In general, gain-of-function mutations destroy the auto-inhibition state from wild-type SHP2, leading to consistency activation of SHP2. We illustrated how somatic or germline mutation of SHP2 plays an oncogenic role in tumorigenesis, stemness maintenance, invasion, etc. Moreover, the small-molecule SHP2 inhibitors are considered as a potential strategy for enhancing the efficacy of antitumor immunotherapy and chemotherapy. We also discussed the interconnection between phase separation and activating mutation of SHP2 in drug resistance of antitumor therapy.

Targeting SHP2 as a therapeutic strategy for inflammatory diseases

With the change of lifestyle and the acceleration of aging process, inflammatory diseases have increasingly become one of the most vital threats to global human health. SHP2 protein is a non-receptor tyrosine phosphatase encoded by PTPN11 gene, and it is widely expressed in various tissues and cells. Numerous studies have shown that SHP2 plays important roles in the regulation of inflammatory diseases, including cancer-related inflammation, neurodegenerative diseases and metabolic diseases. In this paper, the roles of SHP2 in inflammatory diseases of various physiological systems were reviewed. At the same time, the latest SHP2 inhibitors were summarized, which will hold a promise for the therapeutic potential in future.

Inhibition of invadopodia formation by diosgenin in tumor cells

Diosgenin is a type of steroid extracted from the rhizome of Dioscorea plants. In traditional Chinese medicine, Dioscorea has the effect of ‘eliminating phlegm, promoting digestion, relaxing tendons, promoting blood circulation and inhibiting malaria’. Recent studies have confirmed that diosgenin exhibits a number of pharmacological effects, including antitumor activities. Through its antitumor effect, diosgenin is able to block tumor progression and increase the survival rate of patients with cancer; ultimately improving their quality of life. However, the mechanism underlying its pharmacological action remains unclear. Once tumor cells reach a metastatic phase, it can be fatal. Increased migration and invasiveness are the hallmarks of metastatic tumor cells. Invadopodia formation is key to maintaining the high migration and invasive ability of tumor cells. Invadopodia are a type of membrane structure process rich in filamentous-actin and are common in highly invasive tumor cells. In addition to actin, numerous actin regulators, including cortical actin-binding protein (Cortactin), accumulate in invadopodia. Cortactin is a microfilament actin-binding protein with special repetitive domains that are directly involved in the formation of the cortical microfilament actin cell skeleton. Cortactin is also one of the main substrates of intracellular Src-type tyrosine protein kinases and represents a highly conserved family of intracellular cortical signaling proteins. In recent years, great progress has been made in understanding the role of Cortactin and its molecular mechanism in cell motility. However, the diosgenin-Cortactin-invadopodia mechanism is still under investigation. Therefore, the present review focused on the current research on the regulation of invadopodia by diosgenin via Cortactin.

Dioscin facilitates ROS-induced apoptosis via the p38-MAPK/HSP27-mediated pathways in lung squamous cell carcinoma

Lung squamous cell carcinoma (SCC) is one of the deadliest cancers both in China and worldwide. To date, the efficacy of lung SCC treatments is limited. Recent studies have elucidated the powerful anti-tumour role of dioscin in different human cancers. Here, our study aims to investigate the effect of dioscin on lung SCC and its underlying mechanism. First, we found that dioscin not only inhibited cell proliferation and cell migration and induced cell apoptosis in lung SCC cells but also suppressed tumour growth in tumour-bearing mice. Furthermore, we noted that the accumulation of intracellular reactive oxygen species (ROS) was triggered by dioscin in lung SCC cells, leading to the phosphorylation of HSP27 through p38-MAPK and consequent cell apoptosis. The activation of p38-MAPK/HSP27 induced by the p38-MAPK activator Anisomycin enhanced the apoptosis of lung SCC cells, while the ROS inhibitor N-acetyl-L-cysteine (NAC) and the p38-MAPK inhibitor SB203580 both attenuated dioscin-mediated cell apoptosis. Moreover, NAC suppressed the activation of p38-MAPK/HSP27 that induced by dioscin. In conclusion, these results confirm that dioscin facilitates ROS-induced apoptosis via the p38-MAPK/HSP27-mediated pathway in lung SCC.

Diosgenin, a steroidal saponin, and its analogs: Effective therapies against different chronic diseases

BACKGROUND

Chronic diseases are a major cause of mortality worldwide, and despite the recent development in treatment modalities, synthetic drugs have continued to show toxic side effects and development of chemoresistance, thereby limiting their application. The use of phytochemicals has gained attention as they show minimal side effects. Diosgenin is one such phytochemical which has gained importance for its efficacy against the life-threatening diseases, such as cardiovascular diseases, cancer, nervous system disorders, asthma, arthritis, diabetes, and many more.

AIM

To evaluate the literature available on the potential of diosgenin and its analogs in modulating different molecular targets leading to the prevention and treatment of chronic diseases.

METHOD

A detailed literature search has been carried out on PubMed for gathering information related to the sources, biosynthesis, physicochemical properties, biological activities, pharmacokinetics, bioavailability and toxicity of diosgenin and its analogs.

KEY FINDINGS

The literature search resulted in many in vitro, in vivo and clinical trials that reported the efficacy of diosgenin and its analogs in modulating important molecular targets and signaling pathways such as PI3K/AKT/mTOR, JAK/STAT, NF-κB, MAPK, etc., which play a crucial role in the development of most of the diseases. Reports have also revealed the safety of the compound and the adaptation of nanotechnological approaches for enhancing its bioavailability and pharmacokinetic properties.

SIGNIFICANCE

Thus, the review summarizes the efficacy of diosgenin and its analogs for developing as a potent drug against several chronic diseases.

Dioscin elicits anti-tumour immunity by inhibiting macrophage M2 polarization via JNK and STAT3 pathways in lung cancer

Tumour‐associated macrophage (TAM) is an important component in tumour microenvironment. Generally, TAM exhibits the function of M2‐like macrophage, which was closely related to angiogenesis and tumour progression. Dioscin, a natural steroidal saponin, has shown its powerful anti‐tumour activity recently. However, the mechanism of dioscin involved in immune regulation is still obscure. Here, we observed dioscin induced macrophage M2‐to‐M1 phenotype transition in vitro and inhibited IL‐10 secretion. Meanwhile, the phagocytosis of macrophages was enhanced. In subcutaneous lung tumour models, dioscin inhibited the augmentation of M2 macrophage populations. Furthermore, dioscin down‐regulated STAT3 and JNK signalling pathways in macrophages in vitro. In BMDMs, activating JNK and inhibiting STAT3 induce macrophages to M1 polarization while inhibiting JNK and activating STAT3 to M2 polarization. Additionally, condition mediums from dioscin‐pre‐treated macrophages inhibited the migration of 3LL cells and the tube‐formation capacity of HUVECs. What's more, dioscin‐mediated macrophage polarization inhibited the in vivo metastasis of 3LL cells. In conclusion, dioscin may act as a new anti‐tumour agent by inhibiting TAMs via JNK and STAT3 pathways in lung cancer.

The prognostic significance of SHP2 and its binding protein Hook1 in non-small cell lung cancer

Background

We previously reported that Hook1 inhibits the phosphatase activity of SHP2 in the regulation of the epithelial-mesenchymal transition (EMT) in lung cancer. In this study, we performed a comprehensive analysis of SHP2 and Hook1 expression and relationships with the prognosis of patients with non-small cell lung cancer (NSCLC).

Materials and methods

A total of 121 patients with NSCLC were included in this study. Expression of SHP2 and Hook1 was assessed by immunohistochemistry and Western blot analysis. The overall survival rate of NSCLC patients was analysed using Cox’s ratio hazard multivariate analysis and the log-rank test.

Results

In tumour tissue specimens, positive expression rates of SHP2 proteins were 58.4% by immunohistochemical analysis. A significant correlation between expression of SHP2 and that of Hook1 was observed. Based on Western blot analysis, we found that Hook1 was downregulated and that SHP2 has a tendency to overexpress without statistical significance in NSCLC tissues compared with their levels in normal lung tissues. The median overall survival (OS) of NSCLC patients who presented low levels of SHP2 expression were better (40 vs 24 months, p=0.004) than those of patients who exhibited high levels of SHP2 expression. The results of multivariate analysis showed that the level of SHP2 expression was an independent prognostic factor for OS.

Conclusion

SHP2 might play an important role in NSCLC and has the potential to serve as a clinical biomarker or NSCLC.

Recent Advances in the Pharmacological Activities of Dioscin

Dioscin is a typical saponin with multiple pharmacological activities. The past few years have seen an emerging interest in and growing research on this pleiotropic saponin. Here, we review the emerging pharmacological activities reported recently, with foci on its antitumor, antimicrobial, anti-inflammatory, antioxidative, and tissue-protective properties. The potential use of dioscin in therapies of diverse clinical disorders is also discussed.

Blocking ROR1 enhances the roles of erlotinib in lung adenocarcinoma cell lines

Treatment strategies involving tyrosine kinase inhibitors (TKIs) for patients with non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) mutations have advanced significantly; however, challenges still remain regarding the development of resistance. It has been reported that receptor tyrosine kinase-like orphan receptor 1 (ROR1) acts as a hepatocyte growth factor receptor (MET) and c-Src substrate, and that the extracellular domain of ROR1 is associated with EGFR to sustain EGFR-ERBB3-PI3K signaling. Our previous study reported that blocking ROR1 significantly decreased the activity of key signal molecules in the AKT/mammalian target of rapamycin (mTOR) signaling pathway, which was associated with a significant increase of apoptosis and significant decrease of proliferation of lung adenocarcinoma cells. The present study hypothesized that inhibiting ROR1 could potentially prevent erlotinib resistance in NSCLC cell lines. Investigations were performed with two erlotinib-resistant cell lines XLA-07 and NCI-H1975, and an erlotinib-acquired-resistant cell line PC-9erlo, which was developed from its parental cell line PC-9. It was identified that the inhibition of ROR1 via small interfering RNA treatment significantly improved the anti-proliferation and apoptosis-inducing roles of erlotinib in TKI-resistant tumor cells. This was in accordance with the activity of key molecules of the AKT/mTOR signaling pathway, including glycogen synthase kinase-3α/β (GSK-3α/β), phosphatase and tensin homolog (PTEN), AKT, mTOR and ribosomal protein S6 kinase β-1 (p70S6K). The current data suggest that targeting ROR1 is a potential novel treatment strategy for patients with ROR1-positive NSCLC, particularly those with acquired resistance to EGFR-TKI.

Inducible SHP-2 activation confers resistance to imatinib in drug-tolerant chronic myeloid leukemia cells

BCR-ABL kinase mutations, accounting for clinical resistance to tyrosine kinase inhibitor (TKI) such as imatinib, frequently occur in acquired resistance or in advanced phases of chronic myeloid leukemia (CML). Emerging evidence implicates a critical role for non-mutational drug resistance mechanisms underlying the survival of residual cancer 'persister' cells. Here, we utilized non-mutational imatinib-resistant K562/G cells to reveal SHP-2 as a resistance modulator of imatinib treatment response during the early phase. SHP-2 phosphorylation was significantly higher in K562/G cells than in sensitive K562 cells. In K562 cells, both short-term and long-term exposure to imatinib induced SHP-2 phosphorylation. Consistently, gain- and loss-of-function mutants in SHP-2 proved its regulation of imatinib resistance. SHP-2 inhibitor and imatinib exhibited a strong antitumor synergy in in vitro and in vivo K562/G models. Mechanistically, dual SHP-2 and BCR-ABL inhibition blocked RAF/MEK/ERK and PI3K/AKT/mTOR pathways, respectively, leading to dramatic apoptotic death of K562/G cells. In conclusion, our results highlight that SHP-2 could be exploited as a biomarker and therapeutic target during the early phase of imatinib resistance development in CML.