Chemoresistance In Non-small Cell Lung Cancer Research Articles

Matrine alkaloids modulating DNA damage repair in chemoresistant non-small cell lung cancer cells

BackgroundNon-small cell lung cancer (NSCLC) presents a significant challenge in the medical field due to its high incidence and resistance to chemotherapy. Chemoresistance in NSCLC diminishes treatment efficacy and contributes to poor patient outcomes. Matrine alkaloids have shown promise in reversing chemotherapy resistance in NSCLC by targeting DNA repair mechanisms.MethodsUtilizing molecular dynamics simulations, we explored the interactions between Matrine alkaloids and DNA repair-related proteins to elucidate their impact on NSCLC cells. In vitro experiments involved treating A549/DDP cells with Matrine alkaloids to evaluate their sensitizing effects on lung cancer cells. Additionally, animal model experiments were conducted to validate the therapeutic potential of Matrine alkaloids in NSCLC treatment.ResultsOur findings demonstrate that Matrine alkaloids disrupt DNA damage repair processes in NSCLC cells, leading to increased sensitivity to chemotherapy. Molecular docking studies revealed the intricate mechanisms by which Matrine alkaloids interact with DNA repair proteins, impacting cell survival and proliferation. Both cell experiments and animal models confirmed the chemosensitizing effects of Matrine alkaloids in NSCLC treatment.ConclusionMatrine alkaloids offer a promising avenue for overcoming chemotherapy resistance in NSCLC by interfering with DNA repair pathways. This study lays a solid foundation for future clinical investigations into the potential of Matrine alkaloids as effective therapeutic agents for enhancing NSCLC treatment outcomes.

LncRNA HAR1A inhibits non-small cell lung cancer growth by downregulating c-MYC transcripts and facilitating its proteasomal degradation

Non-small cell lung cancer (NSCLC) is a primary cause of cancer-related mortality on a global scale. Research increasingly shows that long non-coding RNAs (lncRNAs) play crucial regulatory roles and serve as biomarkers for diagnosis, prognosis, therapy monitoring, and druggable targets in NSCLC. We previously identified HAR1A as a tumor-suppressing lncRNA in NSCLC, with its loss also observed in oral and hepatocellular carcinoma. This study aimed to expand the understanding of the functional role of HAR1A in NSCLC and uncover its underlying mechanisms. Our results demonstrated that elevating HAR1A levels impeded NSCLC cell proliferation and migration but promoted apoptosis, thereby boosting their susceptibility to cisplatin. Subsequently, we discovered that HAR1A enhanced cisplatin’s cytotoxicity in NSCLC cells by curbing adaptive autophagy through the downregulation of MYC. Further analysis revealed that HAR1A suppresses MYC by both lowering its transcript levels and promoting protein ubiquitination and degradation, thereby restricting tumor cell proliferation, migration, and adaptive autophagy. In exploring MYC’s targets, we observed that MYC upregulated the transcription of heat shock protein 90 alpha family class B member 1 (HSP90AB1/HSP90β) gene. Rescue experiments verified that HAR1A mitigated NSCLC cell proliferation and migration and induced apoptosis through the MYC/HSP90β axis. Finally, we confirmed that HAR1A overexpression increased cisplatin efficacy in nude mouse NSCLC xenograft models.In conclusion, the findings suggest that HAR1A could be a promising therapeutic target in treating NSCLC and biomarkers for predicting chemotherapy outcomes. This study provides new insights into the molecular mechanisms of chemoresistance in NSCLC and underscores the potential of lncRNA-based strategies in cancer therapy.

Targeting AKR1B10 by Drug Repurposing with Epalrestat Overcomes Chemoresistance in Non-Small Cell Lung Cancer Patient-Derived Tumor Organoids.

Systemic treatments given to patients with non-small cell lung cancer (NSCLC) are often ineffective due to drug resistance. In the present study, we investigated patient-derived tumor organoids (PDTO) and matched tumor tissues from surgically treated patients with NSCLC to identify drug repurposing targets to overcome resistance toward standard-of-care platinum-based doublet chemotherapy. PDTOs were established from 10 prospectively enrolled patients with non-metastatic NSCLC from resected tumors. PDTOs were compared with matched tumor tissues by histopathology/immunohistochemistry, whole exome sequencing, and transcriptome sequencing. PDTO growths and drug responses were determined by measuring 3D tumoroid volumes, cell viability, and proliferation/apoptosis. Differential gene expression analysis identified drug-repurposing targets. Validations were performed with internal/external data sets of patients with NSCLC. NSCLC cell lines were used for aldo-keto reductase 1B10 (AKR1B10) knockdown studies and xenograft models to determine the intratumoral bioavailability of epalrestat. PDTOs retained histomorphology and pathological biomarker expression, mutational/transcriptomic signatures, and cellular heterogeneity of the matched tumor tissues. Five (50%) PDTOs were chemoresistant toward carboplatin/paclitaxel. Chemoresistant PDTOs and matched tumor tissues demonstrated overexpression of AKR1B10. Epalrestat, an orally available AKR1B10 inhibitor in clinical use for diabetic polyneuropathy, was repurposed to overcome chemoresistance of PDTOs. In vivo efficacy of epalrestat to overcome drug resistance corresponded to intratumoral epalrestat levels. PDTOs are efficient preclinical models recapitulating the tumor characteristics and are suitable for drug testing. AKR1B10 can be targeted by repurposing epalrestat to overcome chemoresistance in NSCLC. Epalrestat has the potential to advance to clinical trials in patients with drug-resistant NSCLC due to favorable toxicity, pharmacological profile, and bioavailability.

Inducing ferroptosis by traditional medicines: a novel approach to reverse chemoresistance in lung cancer

Lung cancer is the leading cause of global cancer-related deaths. Platinum-based chemotherapy is the first-line treatment for the most common type of lung cancer, i.e., non-small-cell lung cancer (NSCLC), but its therapeutic efficiency is limited by chemotherapeutic resistance. Therefore, it is vital to develop effective therapeutic modalities that bypass the common molecular mechanisms associated with chemotherapeutic resistance. Ferroptosis is a form of non-apoptotic regulated cell death characterized by iron-dependent lipid peroxidation (LPO). Ferroptosis is crucial for the proper therapeutic efficacy of lung cancer-associated chemotherapies. If targeted as a novel therapeutic mechanism, ferroptosis modulators present new opportunities for increasing the therapeutic efficacy of lung cancer chemotherapy. Emerging studies have revealed that the pharmacological induction of ferroptosis using natural compounds boosts the efficacy of chemotherapy in lung cancer or drug-resistant cancer. In this review, we first discuss chemotherapeutic resistance (or chemoresistance) in lung cancer and introduce the core mechanisms behind ferroptosis. Then, we comprehensively summarize the small-molecule compounds sourced from traditional medicines that may boost the anti-tumor activity of current chemotherapeutic agents and overcome chemotherapeutic resistance in NSCLC. Cumulatively, we suggest that traditional medicines with ferroptosis-related anticancer activity could serve as a starting point to overcome chemotherapeutic resistance in NSCLC by inducing ferroptosis, highlighting new potential therapeutic regimens used to overcome chemoresistance in NSCLC.

Linc00673-V3 positively regulates autophagy by promoting Smad3-mediated LC3B transcription in NSCLC.

Since its first discovery, long noncoding RNA Linc00673 has been linked to carcinogenesis and metastasis of various human cancers. Linc00673 had five transcriptional isoforms and their biological functions remained to be explored. Here we have reported that Linc00673-V3, one of the isoforms of Linc00673, promoted non-small cell lung cancer chemoresistance, and increased Linc00673-V3 expression level was associated with enhanced autophagy. Mechanistically, we discerned the existence of a stem-loop configuration engendered by the 1-100-nt and 2200-2275-nt fragments within Linc00673-V3. This structure inherently interacted with Smad3, thereby impeding its ubiquitination and subsequent degradation orchestrated by E3 ligase STUB1. The accumulation of Smad3 contributed to autophagy via up-regulation of LC3B transcription and ultimately conferred chemoresistance in NSCLC. Our results revealed a novel transcriptional regulation network between Linc00673-V3, Smad3, and LC3B, which provided an important insight into the interplay between autophagy regulation and non-canonical function of Smad3. Furthermore, the results from in vivo experiments suggested Linc00673-V3 targeted antisense oligonucleotide as a promising therapeutic strategy to overcome chemotherapy resistance in NSCLC.

Abstract 2779: The significance of TIMP-1 and hypoxia in cancer stemness: A synergistic role in chemoresistance

Abstract Chemotherapeutic resistance in non-small-cell lung cancer (NSCLC) poses a formidable clinical challenge. Numerous studies have highlighted the critical role of tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) in tumorigenesis and, increasingly, in the development of chemoresistance. We have studied multiple aspects of the MMP-independent, tumor-promoting function of TIMP1 in human NSCLC. Our recent studies have found a pivotal role for TIMP1 in chemoresistance. In order to gain an enhanced comprehension of the mechanisms underpinning TIMP-1-mediated chemoresistance, we have sought to determine the contribution of CSCs and hypoxia. TIMP-1 plays a role in propagating stemness, although relatively unexplored in the context of CSCs within NSCLC. A second crucial factor in the development of chemoresistance in NSCLC is the interplay between intratumoral hypoxia and CSCs. As the tumor grows, metabolic demand for oxygen increases and hypoxic regions are seen in areas furthest from the blood vessels. We have shown TIMP1 levels to increase under experimentally-induced hypoxia. In the present study, we cultured NSCLC cell lines and their TIMP1 KD clones in an assay with serum-free media and found a significant decrease in spheroid size in TIMP1 KD clones. Postulating a reduction in CSC population in KD clones, we determined the NSCLC CSC markers CD133 and ALDH’s expression in the NT and KD TIMP1 clones. Flow cytometry results showed that CD133pos and ALDHhigh populations were significantly decreased in TIMP1 KD clones relative to NT clones. Moreover, KD clone of TIMP1 showed a decrease in the levels of CSC-specific Transcription factors Oct 4A and Nanog. Taken together, our findings confirm that reduction in TIMP1 expression negatively impacts CSC populations. Furthermore, we determined the mRNA levels of CD44, another CSC marker also expressed in lung cancer is upregulated under hypoxia (1% O2) in both the NT and KD clones of TIMP1. Thus, we postulate that TIMP1 enhances chemoresistance by promoting CSC propagation within a hypoxic tumor microenvironment. Citation Format: Ilamathi Thirusenthilarasan, Wei Xiao, Mumtaz V. Rojiani. The significance of TIMP-1 and hypoxia in cancer stemness: A synergistic role in chemoresistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2779.

The novel miR-873-5p-YWHAE-PI3K/AKT axis is involved in non-small cell lung cancer progression and chemoresistance by mediating autophagy.

Non-small cell lung cancer (NSCLC) encompasses approximately 85% of all lung cancer cases and is the foremost cancer type worldwide; it is prevalent in both sexes and known for its high fatality rate. Expanding scientific inquiry underscores the indispensability of microRNAs in NSCLC. Here, we probed the impact of miR-873-5p on NSCLC development and chemoresistance. qRT‒PCR was used to measure the miR-873-5p level in NSCLC cells with or without chemoresistance. A model of miR-873-5p overexpression was constructed. The proliferation and viability of NSCLC cells were evaluated through CCK8 and colony formation experiments. Cell migration and invasion were monitored via Transwell assays. Western blotting was used to determine the levels of YWHAE, PI3K, AKT, EMT, apoptosis, and autophagy-related proteins. The sensitivity of NSCLC cells to the chemotherapeutic agent gefitinib was assessed. Additionally, the correlation of YWHAE with miR-873-5p was validated via a dual-luciferase reporter assay and RNA immunoprecipitation (RIP). Overexpressed miR-873-5p suppressed migration, proliferation, invasion, and EMT while concurrently stimulating apoptotic processes. miR-873-5p was downregulated in NSCLC cells resistant to gefitinib. Upregulating miR-873-5p reversed gefitinib resistance by inducing autophagy. YWHAE was confirmed to be a downstream target of miR-873-5p. YWHAE overexpression promoted the malignant behaviors of NSCLC cells and boosted tumor growth, while these effects were reversed following miR-873-5p overexpression. Subsequent investigations revealed that overexpressing YWHAE promoted PI3K/AKT pathway activation, with miR-873-5p displaying inhibitory effects on the YWHAE-mediated PI3K/AKT signaling cascade. miR-873-5p affects proliferation, invasion, migration, EMT, autophagy, and chemoresistance in NSCLC by controlling the YWHAE/PI3K/AKT axis.

Plk3 Enhances Cisplatin Sensitivity of Nonsmall-Cell Lung Cancer Cells through Inhibition of the PI3K/AKT Pathway via Stabilizing PTEN.

Polo-like kinase 3 (Plk3) is involved in tumor development with a tumor suppressive function. However, the effect of Plk3 on the chemoresistance remains unclear. It has been documented that activation of the PI3K/AKT signaling pathway by PTEN loss significantly enhances chemoresistance in nonsmall-cell lung cancer (NSCLC). This study aims to evaluate the PTEN regulation by Plk3 and identify targets and underlying mechanisms that could be used to relieve chemoresistance. Our results showed that silencing Plk3 reduced PTEN expression and activated PI3K/AKT signaling by dephosphorylating and destabilizing PTEN in NSCLC cells. Reducing Plk3 expression promoted drug resistance to cisplatin (DDP), while overexpressing Plk3 promoted DDP sensitivity. However, these effects were attenuated when MK2206, a PI3K/AKT inhibitor, was applied. In conclusion, upregulation of Plk3 sensitized NSCLC cells toward DDP, which provides a potential target to restore DDP chemoresponse. We provided novel evidence that the PTEN/PI3K/AKT signaling pathway could be regulated by Plk3 through phosphorylation of PTEN and highlighted the critical role of Plk3 in the DDP resistance of NSCLC.

IL-8 from CD248-expressing cancer-associated fibroblasts generates cisplatin resistance in non-small cell lung cancer.

Chemotherapy-resistant non-small cell lung cancer (NSCLC) presents a substantial barrier to effective care. It is still unclear how cancer-associated fibroblasts (CAFs) contribute to NSCLC resistance to chemotherapy. Here, we found that CD248+ CAFs released IL-8 in NSCLC, which, in turn, enhanced the cisplatin (CDDP) IC50 in A549 and NCI-H460 while decreasing the apoptotic percentage of A549 and NCI-H460 invitro. The CD248+ CAFs-based IL-8 secretion induced NSCLC chemoresistance by stimulating nuclear factor kappa B (NF-κB) and elevating ATP-binding cassette transporter B1 (ABCB1). We also revealed that the CD248+ CAFs-based IL-8 release enhanced cisplatin chemoresistance in NSCLC mouse models invivo. Relative to wild-type control mice, the CD248 conditional knockout mice exhibited significant reduction of IL-8 secretion, which, in turn, enhanced the therapeutic efficacy of cisplatin invivo. In summary, our study identified CD248 activates the NF-κB axis, which, consecutively induces the CAFs-based secretion of IL-8, which promotes NSCLC chemoresistance. This report highlights a potential new approach to enhancing the chemotherapeutic potential of NSCLC-treating cisplatin.

Targeting PAK4 reverses cisplatin resistance in NSCLC by modulating ER stress

Chemoresistance poses a significant impediment to effective treatments for non-small-cell lung cancer (NSCLC). P21-activated kinase 4 (PAK4) has been implicated in NSCLC progression by invasion and migration. However, the involvement of PAK4 in cisplatin resistance is not clear. Here, we presented a comprehensive investigation into the involvement of PAK4 in cisplatin resistance within NSCLC. Our study revealed enhanced PAK4 expression in both cisplatin-resistant NSCLC tumors and cell lines. Notably, PAK4 silencing led to a remarkable enhancement in the chemosensitivity of cisplatin-resistant NSCLC cells. Cisplatin evoked endoplasmic reticulum stress in NSCLC. Furthermore, inhibition of PAK4 demonstrated the potential to sensitize resistant tumor cells through modulating endoplasmic reticulum stress. Mechanistically, we unveiled that the suppression of the MEK1-GRP78 signaling pathway results in the sensitization of NSCLC cells to cisplatin after PAK4 knockdown. Our findings establish PAK4 as a promising therapeutic target for addressing chemoresistance in NSCLC, potentially opening new avenues for enhancing treatment efficacy and patient outcomes.

Inhibition of NNMT enhances drug sensitivity in lung cancer cells through mediation of autophagy.

This study aimed to investigate the role of Nicotinamide N-methyltransferase (NNMT) in the drug sensitivity of non-small cell lung cancer (NSCLC) cells, with a focus on its impact on autophagy and resistance to the chemotherapeutic agent osimertinib. The study hypothesized that NNMT knockdown would enhance drug sensitivity by modifying autophagic processes, providing a potential new therapeutic target for overcoming chemoresistance in lung cancer. Proteomic analysis was utilized to identify changes in protein expression following NNMT knockdown in H1975 and H1975 osimertinib resistance (H1975OR) lung cancer cell lines. Gene expression patterns and their correlation with NNMT expression in lung cancer patients were analyzed using The Cancer Genome Atlas (TCGA) dataset. Additionally, a predictive model for lung cancer survival was developed via lasso regression analysis based on NNMT-associated gene expression. Drug sensitivity was assessed using the IC50 values and apoptosis ratio, and autophagy was evaluated through Western blot and flow cytometric analysis. Significant variations in the expression of 1,182 proteins were observed following NNMT knockdown, with a significant association with autophagy-related genes. Analysis of gene expression patterns unveiled a significant correlation between NNMT expression and specific changes in gene expression in lung cancer. The predictive model successfully forecasted lung cancer patient survival outcomes, highlighting the potential of NNMT-associated genes in predicting patient survival. Knockdown of NNMT reversed osimertinib resistance in H1975 cells, as evidenced by altered IC50 values and apoptosis ratio, and changes were observed in autophagy markers. Knockdown of NNMT in lung cancer cells enhances drug sensitivity by modulating autophagy, providing a promising therapeutic target to overcome chemoresistance in NSCLC. The study underscores the importance of NNMT in lung cancer pathology and underscores its potential as a predictive marker for clinical outcomes. Additionally, the developed predictive model further supports the clinical relevance of NNMT-associated gene expression in improving the prognosis of lung cancer patients.

Targeting METTL3 enhances the chemosensitivity of non-small cell lung cancer cells by decreasing ABCC2 expression in an m6A-YTHDF1-dependent manner.

Patients with non-small cell lung cancer (NSCLC) are easily resistant to first-line chemotherapy with paclitaxel (PTX) or carboplatin (CBP). N6-methyladenosine (m6A) methyltransferase-like 3 (METTL3) has crucial functions in m6A modification and tumorigenesis. However, its role in chemoresistance of NSCLC is still elusive. Here, we demonstrated that METTL3 inhibitor STM2457 significantly reduced the IC50 values of PTX or CBP in NSCLC cells, and they showed a synergistic effect. Comparing with monotherapy, a combination of STM2457 and PTX or CBP exhibited more potent in vitro and in vivo anti-tumor efficacy. In addition, we found that ATP binding cassette subfamily C member 2 (ABCC2) was responsively elevated in cytomembrane after PTX or CBP treatment, and targeting METTL3 could reverse this effect. Mechanistically, targeting METTL3 decreased the m6A modification of ABCC2 mRNA and accelerated its mRNA degradation. Further studies revealed that YTHDF1 could bind and stabilize the m6A-modified mRNA of ABCC2, while YTHDF1 knockdown promoted it mRNA degradation. These results, taken together, demonstrate that targeting METTL3 enhances the sensitivity of NSCLC cells to PTX or CBP by decreasing the cytomembrane-localized ABCC2 in an m6A-YTHDF1-dependent manner, and suggest that METTL3 may be a potential therapeutic target for acquired resistance to PTX or CBP in NSCLC.

Targeting lncRNA16 by GalNAc-siRNA conjugates facilitates chemotherapeutic sensibilization via the HBB/NDUFAF5/ROS pathway.

Chemoresistance is a significant barrier to effective cancer treatment. Potential mechanisms for chemoresistance include reactive oxygen species (ROS) accumulation and expression of chemoresistance-promoting genes. Here, we report a novel function of lncRNA16 in the inhibition of ROS generation and the progression of chemoresistance. By analyzing the serum levels of lncRNA16 in a cohort of 35 patients with non-small cell lung cancer (NSCLC) and paired serum samples pre- and post-treatment from 10 NSCLC patients receiving neoadjuvant platinum-based chemotherapy, performing immunohistochemistry (IHC) assays on 188 NSCLC tumor samples, using comprehensive identification of RNA-binding proteins by mass spectrometry (ChIRP-MS) assays, as well as RNA immunoprecipitation (RIP) and RNA pull-down analyses, we discovered that patients with increased serum levels of lncRNA16 exhibited a poor response to platinum-based chemotherapy. The expression of hemoglobin subunit beta (HBB) and NDUFAF5 significantly increases with the development of chemoresistance. LncRNA16 binds to HBB and promotes HBB accumulation by inhibiting autophagy. LncRNA16 can also inhibit ROS generation via the HBB/NDUFAF5 axis and function as a scaffold to facilitate the colocalization of HBB and NDUFAF5 in the mitochondria. Importantly, preclinical studies in mouse models of chemo-resistant NSCLC have suggested that lncRNA16 targeting by trivalent N-acetylgalactosamine (GalNAc)-conjugated siRNA restores chemosensitivity and results in tumor growth inhibition with no detectable toxicity in vivo. Overall, lncRNA16 is a promising therapeutic target for overcoming chemoresistance, and the combination of first-line platinum-based chemotherapy with lncRNA16 intervention can substantially enhance anti-tumor efficacy.

Wild-type IDH1 maintains NSCLC stemness and chemoresistance through activation of the serine biosynthetic pathway

Tumor-initiating cells (TICs) reprogram their metabolic features to meet their bioenergetic, biosynthetic, and redox demands. Our previous study established a role for wild-type isocitrate dehydrogenase 1 (IDH1 WT ) as a potential diagnostic and prognostic biomarker for non–small cell lung cancer (NSCLC), but how IDH1 WT modulates NSCLC progression remains elusive. Here, we report that IDH1 WT activates serine biosynthesis by enhancing the expression of phosphoglycerate dehydrogenase (PHGDH) and phosphoserine aminotransferase 1 (PSAT1), the first and second enzymes of de novo serine synthetic pathway. Augmented serine synthesis leads to GSH/ROS imbalance and supports pyrimidine biosynthesis, maintaining tumor initiation capacity and enhancing gemcitabine chemoresistance. Mechanistically, we identify that IDH1 WT interacts with and stabilizes PHGDH and fragile X–related protein-1 (FXR1) by impeding their association with the E3 ubiquitin ligase parkin by coimmunoprecipitation assay and proximity ligation assay. Subsequently, stabilized FXR1 supports PSAT1 mRNA stability and translation, as determined by actinomycin D chase experiment and in vitro translation assay. Disrupting IDH1 WT -PHGDH and IDH1 WT -FXR1 interactions synergistically reduces NSCLC stemness and sensitizes NSCLC cells to gemcitabine and serine/glycine–depleted diet therapy in lung cancer xenograft models. Collectively, our findings offer insights into the role of IDH1 WT in serine metabolism, highlighting IDH1 WT as a potential therapeutic target for eradicating TICs and overcoming gemcitabine chemoresistance in NSCLC.

A redox-responsive nanosystem to suppress chemoresistant lung cancer through targeting STAT3

Cancer stem cells (CSCs) have been demonstrated to be involved in tumor initiation and relapse, and the presence of CSCs in the tumor tissue often leads to therapeutic failure. BBI608 has been identified to eliminate CSCs by inhibiting signal transducer and activator of transcription 3 (STAT3). In this study, we confirm that BBI608 can efficiently suppress the proliferation and migration of non-small cell lung cancer (NSCLC) cells, and specifically kill the stemness-high population in chemoresistant NSCLC cells. To improve its bioavailability and tumor accumulation, BBI608 is successfully encapsulated into redox-responsive PEGylated branched N-(2-hydroxypropyl) methacrylamide (HPMA)-deoxy cholic acid (DA) polymeric nanoparticles (BBI608-SS-NPs). The BBI608-SS-NPs can release the drug in response to high concentrations of intracellular glutathione, and exhibit cytotoxicity against lung cancer cells and CSCs comparable to the free drug BBI608. Furthermore, the BBI608-SS-NPs preferentially accumulate in tumor sites, resulting in a superior anti-tumor efficacy in both cisplatin-resistant cell line-derived xenograft (CDX) and patient-derived xenograft (PDX) models of NSCLC. Mechanistic studies demonstrate that BBI608-SS-NPs not only directly inhibit the downstream genes of the STAT3 pathway, but also indirectly inhibit the Wnt pathway. Overall, this stimuli-responsive polymeric nanoformulation of BBI608 shows great potential in the treatment of chemoresistant NSCLC by targeting CSCs.

Characterization of chemoresistant human non-small cell lung cancer cells by metabolic and lipidomic profiling.

Lung cancer is one of the most malignant cancers and the leading cause of cancer-related deaths worldwide, while acquired chemoresistance would represent a major problem in the treatment of non-small cell lung cancer (NSCLC) because of the reduced treatment effect and increased rates of recurrence. To establish the chemoresistant NSCLC cells, doxorubicin was treated to A549 cells over 3 months at gradually increasing concentrations from 0.03 to 0.5 µM. Real-time PCR and Western blotting were employed for investigating mRNA and protein expression of the glutathione peroxidase (GPX) protein family and multidrug resistance protein 1 (MRP1) in A549 and A549/CR cells. We also employed gas chromatography mass-spectrometry and nano electrospray ionization mass-spectrometry coupled with multivariate statistical analysis to characterize the unique metabolic and lipidomic profiles of chemoresistant NSCLC cells in order to identify potential therapeutic targets. Reactive oxygen species levels were decreased, and mRNA and protein levels of GPX2 and multidrug resistance protein 1 (MRP1) were increased in A549/CR. We identified 87 metabolites and intact lipid species in A549 and A549/CR. Among these metabolites, lactic acid, glutamic acid, glycine, proline, aspartic acid, succinic acid, and ceramide, alongside the PC to PE ratio, and arachidonic acid-containing phospholipids were suggested as characteristic features of chemoresistant NSCLC cells (A549/CR). This study reveals characteristic feature differences between drug-resistance NSCLC cells and their parental cells. We suggest potential therapeutic targets in chemoresistant NSCLC. Our results provide new insight into metabolic and lipidomic alterations in chemoresistant NSCLC. This could be used as fundamental information to develop therapeutic strategies for the treatment of chemoresistant NSCLC patients.

PHF23 promotes NSCLC proliferation, metastasis, and chemoresistance via stabilization of ACTN4 and activation of the ERK pathway.

At present, non-small cell lung cancer (NSCLC) is still one of the leading causes of cancer-related deaths. Chemotherapy remains the standard treatment for NSCLC. However, the emergence of chemoresistance is one of the major obstacles to lung cancer treatment. Plant homologous structural domain finger protein 23 (PHF23) plays crucial roles in multiple cell fates. However, the clinical significance and biological role of PHF23 in NSCLC remain elusive. The Cancer Genome Atlas data mining, NCBI/GEO data mining, and western blotting analysis were employed to characterize the expression of PHF23 in NSCLC cell lines and tissues. Statistical analysis of immunohistochemistry and the Kaplan-Meier Plotter database were used to investigate the clinical significance of PHF23. A series of in vivo and in vitro assays, including assays for colony formation, cell viability, 5-ethynyl-2'-deoxyuridine (EDU incorporation) and Transwell migration, flow cytometry, RT-PCR, gene set enrichment analysis, co-immunoprecipitation analysis, and a xenograft tumor model, were performed to demonstrate the effects of PHF23 on the chemosensitivity of NSCLC cells and to clarify the underlying molecular mechanisms. PHF23 is overexpressed in NSCLC cell lines and tissues. High PHF23 levels correlate with short survival times and a poor response to chemotherapy in NSCLC patients. PHF23 overexpression facilitates cell proliferation, migration and sensitizes NSCLC cells to Cisplatin and Docetaxel by promoting DNA damage repair. Alpha-actinin-4 (ACTN4), as a downstream regulator, interacts with PHD domain of PHF23. Moreover, PHF23 is involved in ACTN4 stabilization by inhibiting its ubiquitination level. These results show that PHF23 plays an important role in the development and progression of NSCLC and suggest that PHF23 may serve as a therapeutic target in NSCLC patients.

Survivin degradation by bergenin overcomes pemetrexed resistance.

Chemoresistance is a primary factor for treatment failure and tumor recurrence in non-small cell lung cancer (NSCLC) patients. The oncoprotein survivinis commonly upregulated in human malignancies and is associated with poor prognosis, but its effect on carcinogenesis and chemoresistance in NSCLC is not yet evident, and to explore an effective inhibitor targeting survivin expression is urgently needed. The protumor characteristics of survivin and antitumor activities of bergenin in NSCLC cells were examined by MTS, colony formation assays, immunoblot, immunohistochemistry, and in vivo xenograft development. Survivin was upregulated in non-small cell lung cancer (NSCLC) tissues, while its depletion inhibited NSCLC tumorigenesis. The current study focused on bergenin, identifying its effective antitumor effect on NSCLC cells both in vivo and in vitro. The results showed that bergenin could inhibit cell proliferation and induce the intrinsic pathway of apoptosis via downregulating survivin. Mechanistically, bergenin reduced the phosphorylation of survivin via inhibiting the Akt/Wee1/CDK1 signaling pathway, thus resulting in enhanced interaction between survivin and E3 ligase Fbxl7 to promote survivin ubiquitination and degradation. Furthermore, bergenin promoted chemoresistance in NSCLC cells re-sensitized to pemetrexed treatment. Survivin overexpression is required for maintaining multiple malignant phenotypes of NSCLC cells. Bergenin exerts a potent antitumor effect on NSCLC via targeting survivin, rendering it a promising agent for the treatment of NSCLC.

Skp2-mediated MLKL degradation confers cisplatin-resistant in non-small cell lung cancer cells

Non-small cell lung cancer (NSCLC) is the most prevalent type of cancer and the leading cause of cancer-related death. Chemotherapeutic resistance is a major obstacle in treating NSCLC patients. Here, we discovered that the E3 ligase Skp2 is overexpressed, accompanied by the downregulation of necroptosis-related regulator MLKL in human NSCLC tissues and cell lines. Knockdown of Skp2 inhibited viability, anchorage-independent growth, and in vivo tumor development of NSCLC cells. We also found that the Skp2 protein is negatively correlated with MLKL in NSCLC tissues. Moreover, Skp2 is increased and accompanied by an upregulation of MLKL ubiquitination and degradation in cisplatin-resistant NSCLC cells. Accordingly, inhibition of Skp2 partially restores MLKL and sensitizes NSCLC cells to cisplatin in vitro and in vivo. Mechanistically, Skp2 interacts and promotes ubiquitination-mediated degradation of MLKL in cisplatin-resistant NSCLC cells. Our results provide evidence of an Skp2-dependent mechanism regulating MLKL degradation and cisplatin resistance, suggesting that targeting Skp2-ubiquitinated MLKL degradation may overcome NSCLC chemoresistance.

USP51/PD-L1/ITGB1-deployed juxtacrine interaction plays a cell-intrinsic role in promoting chemoresistant phenotypes in non-small cell lung cancer.

Programmed death ligand 1 (PD-L1) has been demonstrated to facilitate tumor progression and therapeutic resistance in an immune-independent manner. Nevertheless, the function and underlying signaling network(s) of cancer cell-intrinsic PD-L1 action remain largely unknown. Herein, we sought to better understand how ubiquitin-specific peptidase 51 (USP51)/PD-L1/integrin beta-1 (ITGB1) signaling performs a cell-intrinsic role in mediating chemotherapeutic resistance in non-small cell lung cancer (NSCLC). Western blotting and flow cytometry were employed for PD-L1 detection in NSCLC cell lines. Coimmunoprecipitation and pulldown analyses, protein deubiquitination assay, tissue microarray, bioinformatic analysis and molecular biology methods were then used to determine the significance of PD-L1 in NSCLC chemoresistance and associated signaling pathways in several different cell lines, mouse models and patient tissue samples. Ubiquitin-7-amido-4-methylcoumarin (Ub-AMC)-based deubiquitinase activity, cellular thermal shift and surface plasmon resonance (SPR) analyses were performed to investigate the activity of USP51 inhibitors. We provided evidence that cancer cell-intrinsic PD-L1 conferred the development of chemoresistance by directly binding to its membrane-bound receptor ITGB1 in NSCLC. At the molecular level, PD-L1/ITGB1 interaction subsequently activated the nuclear factor-kappa B (NF-κB) axis to elicit poor response to chemotherapy. We further determined USP51 as a bona fide deubiquitinase that targeted the deubiquitination and stabilization of the PD-L1 protein in chemoresistant NSCLC cells. Clinically, we found a significant direct relationship between the USP51, PD-L1 and ITGB1 contents in NSCLC patients with chemoresistant potency. The elevated USP51, PD-L1 and ITGB1 levels were strongly associated with worse patient prognosis. Of note, we identified that a flavonoid compound dihydromyricetin (DHM) acted as a potential USP51 inhibitor and rendered NSCLC cells more sensitive to chemotherapy by targeting USP51-dependent PD-L1 ubiquitination and degradation in vitro and in vivo. Together, our results demonstrated that the USP51/PD-L1/ITGB1 network potentially contributes to the malignant progression and therapeutic resistance in NSCLC. This knowledge is beneficial to the future design of advanced cancer therapy.