Cisplatin-resistant Non-small Cell Lung Cancer Cells Research Articles

Silencing Nrf2 in cisplatin resistant non-small cell lung cancer cells augments sensitivity towards EGFR inhibitor

Recently, non-small cell lung cancer (NSCLC) has been the prime concern of cancer clinicians due to its high mortality rate worldwide. Cisplatin, a platinum derivative, has been used as a therapeutic option for treating metastatic NSCLC for several years. However, acquired, or intrinsic drug resistance to Cisplatin is the major obstacle to the successful treatment outcome of patients. Dysregulation of Nrf2 (nuclear factor erythroid 2-related factor 2) and EGFR (epidermal growth factor receptor) signaling have been associated with cellular proliferation, cancer initiation, progression and confer drug resistance to several therapeutic agents including Cisplatin in various cancers. To dissect the molecular mechanism of EGFR activation in resistant cells, we developed Cisplatin-resistant (CisR) human NSCLC cell lines (A549 and NCIH460) with increasing doses of Cisplatin treatment over a 3-month period. CisR cells demonstrated increased proliferative capacity, clonogenic survivability and drug efflux activity compared to the untreated parental (PT) cells. These resistant cells also showed higher levels of Nrf2 and EGFR expression. Here, we found that Nrf2 upregulates both basal and inducible expression of EGFR in these CisR cells at the transcriptional level. Moreover, genetic inhibition of Nrf2 with siRNA in CisR cells showed increased sensitivity towards the EGFR tyrosine kinase inhibitor (TKIs), AG1478. Our study, therefore suggests the use of Nrf2 inhibitors in combinatorial therapy with EGFR TKIs for the treatment of resistant NSCLC.

A novel combinatory treatment against a CDDP-resistant non-small cell lung cancer based on a Ruthenium(II)-cyclopentadienyl compound

The therapeutic approach to many solid tumors, including non-small cell lung cancer (NSCLC), is mainly based on the use of platinum-containing anticancer agents and is often characterized by acquired or intrinsic resistance to the drug. Therefore, the search for safer and more effective drugs is still an open challenge.Two organometallic ruthenium(II)-cyclopentadienyl compounds [Ru(η5-C5H4CHO)(Me2bipy)(PPh3)]+ (RT150) and [Ru(η5-C5H4CH2OH)(Me2bipy)(PPh3)][CF3SO3] (RT151) were tested against a panel of cisplatin-resistant NSCLC cell lines and xenografts. They were more effective than cisplatin in inducing oxidative stress and DNA damage, affecting the cell cycle and causing apoptosis. Importantly, they were found to be inhibitors of drug efflux transporters. Due to this property, the compounds significantly increased the retention and cytotoxicity of cisplatin within NSCLC cells. Notably, they did not display high toxicity in vitro against non-transformed cells (red blood cells, fibroblasts, bronchial epithelial cells, cardiomyocytes, and endothelial cells). Both compounds induced vasorelaxation and reduced endothelial cell migration, suggesting potential anti-angiogenic properties. RT151 confirmed its efficacy against NSCLC xenografts resistant to cisplatin. Either alone or combined with low doses of cisplatin, RT151 showed a good biodistribution profile in the liver, kidney, spleen, lung, and tumor. Hematochemical analysis and post-mortem organ pathology confirmed the safety of the compound in vivo, also when combined with cisplatin.To sum up, we have confirmed the effectiveness of a novel class of drugs against cisplatin-resistant NSCLC. Additionally, the compounds have a good biocompatibility and safety profile.

XAF1 overexpression inhibits the malignant progression and cisplatin resistance of NSCLC by activating endoplasmic reticulum stress.

XIAP-associated factor 1 (XAF1) has been found to participate in the progression of multiple human cancers. Nevertheless, its role as well as the reaction mechanism in non-small cell lung cancer (NSCLC) still remains obscure. In this study, the protein expression of XAF1 in NSCLC cell lines was evaluated using western blot. With the employment of CCK-8 assay, EdU staining, wound healing and transwell, capabilities of NSCLC cells to proliferate, migrate and invade were assessed. Cell apoptotic level and cell cycle were resolved utilizing flow cytometry. Western blot was applied for the estimation of apoptosis- and endoplasmic reticulum (ER) stress-related proteins. It was discovered that XAF1 expression was conspicuously reduced in NSCLC cell lines. XAF1 overexpression suppressed H1299 cell proliferative, invasive and migrative capabilities, but exhibited promotive effects on cell cycle arrest. Meanwhile, XAF1 overexpression inhibited cisplatin resistance in H1299 and H1299/DDP cells by promoting cell apoptosis and enhanced the expression levels of ER stress-related proteins CHOP, GRP78 and ATF4. What's more, 4-PBA treatment reversed the impacts of XAF1 overexpression on the proliferative, invasive, migrative and apoptotic capabilities of H1299 cells, as well as cell cycle and cisplatin resistance. In conclusion, XAF1 overexpression impeded the advancement of NSCLC and repressed cisplatin resistance of NSCLC cells through inducing ER stress, which indicated that XAF1 might be a novel targeted-therapy for NSCLC.

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.

α-Hederin promotes ferroptosis and reverses cisplatin chemoresistance in non-small cell lung cancer.

Cisplatin is a core chemotherapy regimen in non-small cell lung cancer (NSCLC). However, chemoresistance to cisplatin leads to a poor prognosis in NSCLC. α-Hederin is a natural compound extracted from Nigella sativa. The study aims to explore the effects of α-Hederin on cisplatin resistance in NSCLC. NSCLC cisplatin-resistant cell lines A549/DPP and PC-9 were cultured to evaluate the efficacy of α-Hederin in the treatment of NSCLC in vitro and in vivo. Metabolomics and RNA-seq analysis were used to determine the potential mechanisms of action of α-Hederin. The results showed that α-Hederin inhibited cisplatin-resistant NSCLC cells proliferation and metastasis. Mice xenograft, orthotopic, and metastatic A549/DPP cell models also showed the anti-tumor effects of α-Hederin. The metabolomics and RNA-seq analysis results showed that α-Hederin activated DDIT3/ATF3 pathway and ferroptosis via silencing SLC7A11 and GPX4. Furthermore, α-Hederin enhanced the nuclear expression of EGR1. Bioinformatics and luciferase experiments confirmed that EGR1 binds to the miR-96-5p promoter region, inhibiting transcription. In addition, miR-96-5p directly suppressed the levels of DDIT3. This study revealed that α-Hederin activated EGR1 nuclear translocation and directly repressed miR-96-5p. It also promoted DDIT3/ATF3-mediated ferroptosis and reversed cisplatin resistance in NSCLC.

LncRNA FEZF1-AS1 facilitates cisplatin resistance in non-small cell lung cancer through modulating the miR-32-5p-glutaminase axis.

Non-small cell lung cancer (NSCLC) is one of the prevalent malignancies. Cisplatin (CDDP) is a conventional chemotherapeutic agent against NSCLC. However, inherent and acquired chemoresistance limited the effectiveness of cisplatin in treatment of NSCLC. This study aimed to investigate the roles and underlying mechanisms of lncRNA-FEZF1-AS1 in mediating cisplatin sensitivity in NSCLC. We found that FEZF1-AS1 levels were significantly higher in lung cancer patients and cell lines. Blocking FEZF1-AS1 sensitized lung cancer cells to cisplatin. Additionally, both glutamine metabolism and FEZF1-AS1 were significantly elevated in cisplatin resistant NSCLC cell lines, A549/CDDP R and SK-MES-1 CDDP/R. Analysis using bioinformatics, RNA pull-down assay and luciferase assay demonstrated that FEZF1-AS1 sponged miR-32-5p, which acted as a tumor suppressor in NSCLC. Glutaminase (GLS), a key enzyme in the glutamine metabolism, was predicted and validated as the direct target of miR-32-5p in NSCLC cells. Inhibiting glutamine metabolism or reducing glutamine supply effectively resensitized cisplatin-resistant cells. Furthermore, restoring miR-32-5p in FEZF1-AS1-overexpressing cisplatin resistant cells successfully overcame FEZF1-AS1-mediated cisplatin resistance by targeting GLS. These findings were further supported by in vivo xenograft mice experiments. This study uncovered the roles and molecular mechanisms of lncRNA FEZF1-AS1 in mediating cisplatin resistance in NSCLC, specifically through modulating the miR-32-5p-GLS axis, providing support for the development of new therapeutic approaches against chemoresistant lung cancer.

β-elemene enhances cisplatin sensitivity of non-small cell lung cancer cells via the miR-17-5p/STAT3 axis.

In China, β-elemene, a sesquiterpene compound derived from Curcuma wenyujin, is clinically used to treat many human malignancies, including non-small cell lung cancer (NSCLC). Nonetheless, the role of β-elemene in regulating cisplatin sensitivity of NSCLC cells and the related mechanisms are not clear. This study was conducted to investigate the role of β-elemene in sensitizing NSCLC cells to cisplatin. In this work, cisplatin-resistant NSCLC cell lines were constructed. CCK-8, colony formation, and flow cytometry assays were executed to examine cell viability, growth, and apoptosis. MiR-17-5p and STAT3 expression levels in cells were detected by qRT-PCR. Western blot was executed to determine the expression levels of STAT3 and apoptosis-related proteins (Bax and Bcl-2) in the cells. Dual-luciferase reporter gene experiments were performed to verify the targeting relationship between miR-17-5p and STAT3. Herein, we report that, β-elemene inhibits the viability, and induces the apoptosis of cisplatin-resistant NSCLC cells. Additionally, β-elemene induces the upregulation miR-17-5p and downregulation of STAT3. STAT3 is validated to be a target of miR-17-5p in NSCLC cells. Additionally, the role of β-elemene to repress the viability of cisplatin-resistant NSCLC cells is partially counteracted by miR-17-5p inhibitor or STAT3 overexpression. In summary, our study suggests that β-elemene enhances cisplatin sensitivity of NSCLC cells by modulating miR-17-5p/STAT3 axis, and it may be a choice for the complementary treatment of NSCLC patients.

Huaier suppresses cisplatin resistance in non-small cell lung cancer by inhibiting the JNK/JUN/IL-8 signaling pathway

Ethnopharmacological relevanceHuaier (Trametes robiniophila Murr), a traditional Chinese medicinal fungus, possesses potent anticancer efficacy and has been used as an adjuvant medication for liver, breast, gastric, intestinal, and non-small cell lung cancer (NSCLC). However, the potential regulatory functions and underlying molecular mechanisms of Huaier in cisplatin resistance of NSCLC remain unknown. AimTo evaluate the potential regulatory functions and underlying molecular mechanisms of Huaier in cisplatin resistance of NSCLC. Materials and methodsIn vitro and in vivo experiments were employed to evaluate the regulatory functions of Huaier in cisplatin-resistant NSCLC cells. Transcriptome sequencing and validation analyses was undertaken to identify the downstream targets of Huaier. Network pharmacology, ultra-performance liquid chromatography-mass spectroscopy, and in vitro and in vivo experiments were performed to identify key small molecule drug candidates in Huaier and the regulatory mechanisms these employ to suppress cisplatin resistance in NSCLC. ResultsHuaier suppressed cisplatin resistance and cancer cell stemness in cisplatin-resistant NSCLC cells, both in vitro and in vivo. Mechanistically, Huaier could suppress expression of interleuken-8 (IL-8) through inhibition of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and activator protein-1 (AP-1), two key transcription factors responsible for the activation of IL-8 transcription. Kaempferol was identified as one of the key small molecule compounds in Huaier that could suppress cisplatin resistance by inhibiting the phosphorylation and nuclear translocation of proto-oncogene c-Jun (JUN) by binding and inhibiting the kinase activity of c-Jun N-terminal protein kinase (JNK). ConclusionsHuaier suppressed cisplatin resistance of NSCLC cells by inhibiting the JNK/JUN/IL-8 signaling pathway.

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.

LncRNA ITGB2-AS1 promotes cisplatin resistance of non-small cell lung cancer by inhibiting ferroptosis via activating the FOSL2/NAMPT axis

ABSTRACT Cisplatin resistance is a major therapeutic challenge in non-small cell lung cancer (NSCLC). Herein, the regulatory role of long non-coding RNA (lncRNA) ITGB2-AS1 in regulating NSCLC cisplatin resistance was investigated. NSCLC cisplatin resistance cells were constructed using A549 and H1975 cells. Cell viability and proliferation were detected by MTT assay and colony formation assay, respectively. Cell apoptosis and cell cycle were examined by flow cytometry. GSH, MDA, ROS, and Fe2+ levels were measured by the corresponding kits. The expressions of ferroptosis-negative regulation genes (GPX4 and SLC7A11) were determined by qRT-PCR and western blot. Molecular interactions were analyzed by RNA pull-down, RIP, ChIP, and dual-luciferase reporter assays. The effects of ITGB2-AS1 silencing on NSCLC cisplatin resistance in vivo were elevated by the tumor xenograft experiment. ITGB2-AS1 expression was increased in NSCLC patients and cisplatin-resistant NSCLC cells, which was positively correlated with ferroptosis-negative regulation genes. ITGB2-AS1 knockdown suppressed resistant cell proliferation and promoted cell apoptosis and ferroptosis. ITGB2-AS1 increased NAMPT expression by binding to FOSL2, thereby repressing p53 expression. The ITGB2-AS1 knockdown also inhibited NSCLC cisplatin resistance in vivo. ITGB2-AS1 promoted NSCLC cisplatin resistance by inhibiting p53-mediated ferroptosis via activating the FOSL2/NAMPT axis.

Dual inhibition of IDO1/TDO2 enhances anti-tumor immunity in platinum-resistant non-small cell lung cancer

BackgroundThe impact of non-small cell lung cancer (NSCLC) metabolism on the immune microenvironment is not well understood within platinum resistance. We have identified crucial metabolic differences between cisplatin-resistant (CR) and cisplatin-sensitive (CS) NSCLC cells with elevated indoleamine 2,3-dioxygenase-1 (IDO1) activity in CR, recognized by increased kynurenine (KYN) production.MethodsCo-culture, syngeneic, and humanize mice models were utilized. C57BL/6 mice were inoculated with either Lewis lung carcinoma mouse cells (LLC) or their platinum-resistant counterpart (LLC-CR) cells. Humanized mice were inoculated with either A (human CS cells) or ALC (human CR cells). Mice were treated with either IDO1 inhibitor or TDO2 (tryptophan 2,3-dioxygenase-2) inhibitor at 200 mg/kg P.O. once a day for 15 days; or with a new-in-class, IDO1/TDO2 dual inhibitor AT-0174 at 170 mg/kg P.O. once a day for 15 days with and without anti-PD1 antibody (10 mg/kg, every 3 days). Immune profiles and KYN and tryptophan (TRP) production were evaluated.ResultsCR tumors exhibited a more highly immunosuppressive environment that debilitated robust anti-tumor immune responses. IDO1-mediated KYN production from CR cells suppressed NKG2D on immune effector natural killer (NK) and CD8+ T cells and enhanced immunosuppressive populations of regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs). Importantly, while selective IDO1 inhibition attenuated CR tumor growth, it concomitantly upregulated the TDO2 enzyme. To overcome the compensatory induction of TDO2 activity, we employed the IDO1/TDO2 dual inhibitor, AT-0174. Dual inhibition of IDO1/TDO2 in CR mice suppressed tumor growth to a greater degree than IDO1 inhibition alone. Significant enhancement in NKG2D frequency on NK and CD8+ T cells and a reduction in Tregs and MDSCs were observed following AT-1074 treatment. PD-L1 (programmed death-ligand-1) expression was increased in CR cells; therefore, we assessed dual inhibition + PD1 (programmed cell death protein-1) blocking and report profound anti-tumor growth and improved immunity in CR tumors which in turn extended overall survival in mice.ConclusionOur study reports the presence of platinum-resistant lung tumors that utilize both IDO1/TDO2 enzymes for survival, and to escape immune surveillance as a consequence of KYN metabolites. We also report early in vivo data in support of the potential therapeutic efficacy of the dual IDO1/TDO2 inhibitor AT-0174 as a part of immuno-therapeutic treatment that disrupts tumor metabolism and enhances anti-tumor immunity.

Abstract 4912: Anticancer activity of Hsp90 inhibitor AUY922 in nasopharyngeal carcinoma and non-small cell lung cancer cells

Abstract Introduction: Nasopharyngeal carcinoma (NPC) and non-small cell lung cancer (NSCLC) are two of the most prevalent cancers in Southern China. Although cisplatin therapy may be initially successful, its effectiveness is often significantly reduced in patients with relapsed disease. There is an urgent need to overcome cisplatin resistance in the treatment of NPC and NSCLC. Luminespib (AUY922) is an experimental drug candidate for the treatment of cancer. It is an inhibitor of heat shock protein 90 (Hsp90), a chaperone protein that plays a role in modifying a variety of proteins involved in tumorigenesis. Hsp90 inhibitors have demonstrated potent activity in preclinical testing and clinical trials against various cancer types. We sought to investigate the preclinical efficacy of AUY922 and evaluate its anticancer effect in cisplatin-resistant NPC and NSCLC cells. Materials and Methods: Two NPC cells (HK1 and Hone1), four NSCLC cells (A549, SW900, NCI-H1975, and HCC4006), one normal lung cells (CCD11Lu), two cisplatin-resistant NPC cells (HK1-R and Hone1-R), and one cisplatin-resistant NSCLC cells (A549-R) were cultured and treated with 100 nM AUY922 for 48 hours. A cell proliferation assay was performed in triplicate to determine the antiproliferative effects of AUY922 on cancer cells. Flow cytometry was used for cell cycle analysis. The apoptotic cells were evaluated by Annexin V and Western blot analysis. Nude mice were used to test the effects of intraperitoneal injection of AUY922 on tumor growth. Results: We found that AUY922 significantly inhibited in vitro growth in all the two NPC (44% and 40%) and four NSCLC (53%, 77%, 50%, and 62%) cells in comparison to the normal lung cells (4%). The two cisplatin-resistant NPC cells (63% and 37%) also showed significant inhibition of viability after treatment with AUY922. However, there was only a slightly reduced viability in the cisplatin-resistant NSCLC cells (14%). Flow cytometry revealed that AUY922 induced G2/M and S phase arrest in HK1 and HK1-R cells. On the other hand, AUY922 also induced pro-apoptotic peaks in A549, A549-R, Hone1, and Hone1-R cells. Interestingly, Annexin V and Western blot analysis showed that cell death was not caused by apoptosis. In vivo, both AUY922 alone and the combination of AUY922 with cisplatin treatments inhibited NPC and NSCLC tumor growth without significant weight loss. In addition, the administration of AUY922 significantly reduced NPC and NSCLC tumor growth in the cisplatin-resistant mouse models. Conclusion: AUY922 exhibits potent anticancer activities in vitro and in vivo. These findings provide evidence that AUY922 could be useful for the treatment of NPC and NSCLC as a single agent or in combination with cisplatin. Most importantly, our results provide a preclinical proof of concept for the efficacy of AUY922 in cisplatin-resistant NPC and NSCLC treatment. Citation Format: William C. Cho, Chi F. Wong. Anticancer activity of Hsp90 inhibitor AUY922 in nasopharyngeal carcinoma and non-small cell lung cancer cells. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4912.

Repurposing of triamterene as a histone deacetylase inhibitor to overcome cisplatin resistance in lung cancer treatment.

Cisplatin is the core chemotherapeutic drug used for first-line treatment of advanced non-small cell lung cancer (NSCLC). However, drug resistance is severely hindering its clinical efficacy. This study investigated the circumvention of cisplatin resistance by repurposing non-oncology drugs with putative histone deacetylase (HDAC) inhibitory effect. A few clinically approved drugs were identified by a computational drug repurposing tool called "DRUGSURV" and evaluated for HDAC inhibition. Triamterene, originally indicated as a diuretic, was chosen for further investigation in pairs of parental and cisplatin-resistant NSCLC cell lines. Sulforhodamine B assay was used to evaluate cell proliferation. Western blot analysis was performed to examine histone acetylation. Flow cytometry was used to examine apoptosis and cell cycle effects. Chromatin immunoprecipitation was conducted to investigate the interaction of transcription factors to the promoter of genes regulating cisplatin uptake and cell cycle progression. The circumvention of cisplatin resistance by triamterene was further verified in a patient-derived tumor xenograft (PDX) from a cisplatin-refractory NSCLC patient. Triamterene was found to inhibit HDACs. It was shown to enhance cellular cisplatin accumulation and potentiate cisplatin-induced cell cycle arrest, DNA damage, and apoptosis. Mechanistically, triamterene was found to induce histone acetylation in chromatin, thereby reducing the association of HDAC1 but promoting the interaction of Sp1 with the gene promoter of hCTR1 and p21. Triamterene was further shown to potentiate the anti-cancer effect of cisplatin in cisplatin-resistant PDX in vivo. The findings advocate further clinical evaluation of the repurposing use of triamterene to overcome cisplatin resistance.

LINC02389/miR-7-5p Regulated Cisplatin Resistance of Non-Small-Cell Lung Cancer via Promoting Oxidative Stress.

Background Non-small-cell lung cancer (NSCLC) is one of the most common malignancies worldwide, and cisplatin-based chemotherapy is the main treatment for NSCLC. However, cisplatin resistance of NSCLC cells is a major challenge for NSCLC treatment. Materials and Methods qRT-PCR and Western blot were performed to detect the expression of LINC02389 and miR-7-5p in NSCLC tissues and cell lines. Cell counting kit-8 (CCK-8) assay and flow cytometry assay were applied to exam cell proliferation and apoptosis rate of NSCLC cells. The interaction between LINC02389 and miR-7-5p was verified by dual luciferase reporter gene assay, RNA pull-down assay, and RNA immunoprecipitation (RIP) assay. Additionally, cisplatin-resistant NSCLC cells were generated to assess the biological function of LINC02389 and miR-7-5p in cisplatin resistance of NSCLC. Results LINC02389 was highly expressed in NSCLC tissues and was correlated with poor prognosis of NSCLC patients. Knockdown of LINC02389 inhibited cell proliferation and promoted cell apoptosis of NSCLC, whereas miR-7-5p knockdown exerted the opposite effects. Moreover, LINC02389 negatively regulated the expression of miR-7-5p. In addition, LINC02389 was overexpressed, yet miR-7-5p was downregulated in cisplatin-resistant NSCLC cells compared with their parental cells. Moreover, oxidative stress biomarkers were overexpressed in cisplatin-resistant cells and were regulated by LINC02389. Besides, LINC02389 could reverse the inhibitory effect of cisplatin on NSCLC cells, which was partially reversed by attenuating the expression of miR-7-5p. Conclusion Our research firstly demonstrated that lncRNA LINC02389 acted as an oncogene to promote progression, oxidative stress, and cisplatin resistance through sponging miR-7-5p and may provide therapeutic targets for NSCLC.

Eukaryotic initiation factor 5A2 mediates hypoxia-induced autophagy and cisplatin resistance

Hypoxia-induced cisplatin resistance is a major challenge during non-small cell lung cancer (NSCLC) treatment. Based on previous studies, we further explored the effect of eukaryotic initiation factor 5A2 (eIF5A2) in hypoxia-induced cisplatin resistance. In this study, we found that autophagy and cisplatin resistance were increased under hypoxic conditions in three different NSCLC cell lines. Compared with that under normoxic conditions, dramatic upregulation of eIF5A2 and hypoxia inducible factor 1 subunit alpha (HIF-1α) levels were detected under hypoxia exposure. Small interfering RNA silencing of HIF-1α resulted in decreased expression of eIF5A2, indicating that eIF5A2 acts downstream of HIF-1α. In addition, the expression of eIF5A2 was significantly higher in NSCLC tumors compared with that in normal tissues. RNA silencing-mediated downregulation of eIF5A2 decreased hypoxia-induced autophagy, thereby reducing hypoxia-induced cisplatin resistance in NSCLC cells. The roles of eIF5A2 in cisplatin resistance were further validated in vivo. Combined treatment using eIF5A2-targeted downregulation together with cisplatin significantly inhibited tumor growth compared with cisplatin alone in the subcutaneous mouse model. In conclusions, eIF5A2 overexpression is involved in hypoxia-induced autophagy during cisplatin resistance. We suggest that a combination of eIF5A2 targeted therapy and cisplatin chemotherapy is probably an effective strategy to reverse hypoxia-induced cisplatin resistance and inhibit NSCLC development.

D-Borneol enhances cisplatin sensitivity via p21/p27-mediated S-phase arrest and cell apoptosis in non-small cell lung cancer cells and a murine xenograft model

BackgroundCisplatin (CDDP) is commonly used to treat non-small cell lung cancer (NSCLC), but the appearance of drug resistance greatly hinders its efficacy. Borneol may promote drug absorption; however, synergism between borneol and CDDP in suppressing NSCLC is not clearly understood. Hence, we investigated borneol as a novel chemosensitizer to support chemotherapeutic efficacy and reduce side effects.MethodsWe compared viability after exposure to d-borneol, l-borneol, and synthetic borneol in two NSCLC cell lines, A549 and H460, and selected the most sensitive cells. We then assessed synergy between borneol forms and CDDP in cisplatin-resistant NSCLC cells, H460/CDDP. Next, we identified effective concentrations and exposure times. Subsequently, we evaluated cell migration via wound healing and cell proliferation via clone formation assay. Then, we focused on P-glycoprotein (P-gp) function, cell cycle, apoptosis, and RNA sequencing to elucidate underlying molecular mechanisms for synergy. Finally, we used an H460/CDDP xenograft tumor model to verify antitumor activity and safety in vivo. Data were examined using one-way analysis of variance (ANOVA) for multiple datasets or t-test for comparisons between two variables.Resultsd-Borneol was more effective in H460 than A549 cells. d-Borneol combined with CDDP showed greater inhibition of cell proliferation, migration, and clone formation in H460/CDDP cells than CDDP alone. RNA sequencing (RNA-seq) analysis identified differentially expressed genes enriched in cell cycle pathways. The impact of d-borneol on CDDP chemosensitivity involved arrest of the cell cycle at S phase via p27/p21-mediated cyclinA2/D3-CDK2/6 signaling and activation of intrinsic apoptosis via p21-mediated Bax/Bcl-2/caspase3 signaling. Further, d-borneol ameliorated drug resistance by suppressing levels and activity of P-gp. Cotreatment with d-borneol and CDDP inhibited tumor growth in vivo and reduced CDDP-caused liver and kidney toxicity.Conclusionsd-Borneol increased the efficacy of cisplatin and reduced its toxicity. This compound has the potential to become a useful chemosensitizer for drug-resistance NSCLC.

Aberrant ROS Served as an Acquired Vulnerability of Cisplatin-Resistant Lung Cancer.

Lung cancer has become a global health issue in recent decades. Approximately 80-85% of cases are non-small-cell lung cancer (NSCLC). Despite the high rate of resistance, cisplatin-base chemotherapy is still the main treatment for NSCLC patients. Thus, overcoming cisplatin resistance is urgently needed in NSCLC therapy. In this study, we identify NADPH metabolism and reactive oxygen species (ROS) levels as the main causes accounting for cisplatin resistance. Based on a small panel consisting of common chemotherapy drugs or compounds, APR-246 is proved to be an effective compound targeting cisplatin-resistant NSCLC cells. APR-246 specially inhibits proliferation and colony formation of cisplatin-resistant cells. In details, APR-246 can significantly cause G0/G1 accumulation and S phase arrest of cisplatin resistant cells and gives rise to severe mitochondria dysfunction as well as elevated apoptosis. Further study proves that it is the aberrant ROS levels as well as NRF2/SLC7A11/GSH axis dysfunction accounting for the specific antitumor effects of APR-246. Scavenging ROS with N-acetylcysteine (NAC) disrupts the inhibitory effect of APR-246 on cisplatin-resistant cells. Mechanistically, NRF2 is specifically degraded by the proteasome following its own ubiquitylation in APR-246-treated cisplatin-resistant cells, which in turn decreases NRF2/SLC7A11/GSH axis activity. Our study provides new insights into the biology driving cisplatin resistance of lung cancer and highlights APR-246 as a potential therapeutic reagent for overcoming cisplatin resistance.

Curcumin Increased the Sensitivity of Non-Small-Cell Lung Cancer to Cisplatin through the Endoplasmic Reticulum Stress Pathway.

Objective Non-small-cell lung cancer (NSCLC) is one of the most lethal cancers. Although cisplatin-based chemotherapies have been regarded as a promising treatment approach, cisplatin resistance still remains one of the major clinical challenges. Curcumin, a naturally occurring polyphenol, has been proved to increase chemotherapeutic efficiency of NSCLC cells. However, the role of curcumin in cisplatin-resistant NSCLC cells has been rarely investigated. This study aims to investigate whether curcumin enhances cisplatin sensitivity of human NSCLC cells and its underlying mechanisms. Method A549/DDP and H1299/DDP cells were treated by DDP or/and curcumin before cell viability, and apoptosis were determined by using a CCK-8 assay and flow cytometer. The expressions of apoptosis and ER stress-related proteins, including cleaved caspase-3, cleaved PARP, CHOP, GRP78, XBP-1, ATF6, and caspase-4, were measured by the qPCR and western blotting. After cotreatment by DDP and curcumin, A549/DDP and H1299/DDP cells were further treated by the ER stress inhibitor, salubrinal (20 μm), after which the cell apoptosis and viability were detected. Result Treatment by DDP and curcumin can substantially decrease cell viability, while can increase the cell apoptosis rate, elevate mRNA and protein expressions of apoptosis and ER stress-related proteins, compared with cells treated by DDP or curcumin alone. Salubrinal treatment can counteract the suppressive effect of DDP and curcumin on cell viability and decrease the cell apoptosis of A549/DDP and H1299/DDP cells. Conclusion Curcumin can increase the sensitivity of NSCLC to cisplatin through an ER stress pathway and thus can be served as one of the molecular targets for overcoming the cisplatin resistance.

BEZ235 reduction of cisplatin resistance on wild-type EGFR non-small cell lung cancer cells

Cisplatin, as a first-line chemotherapy drug for advanced wild-type epidermal growth factor receptor (wtEGFR) non-small cell lung cancer (NSCLC), often loses effectiveness because of acquired drug resistance. We found that ataxia-telangiectasia mutated (ATM), ataxia-telangiectasia and Rad3-related (ATR) and DNA-dependent protein kinase catalytic subunit (DNA-PKcs) of DNA repair kinases and signal transduction molecules, protein kinase B (AKT)/target mammalian target of rapamycin (mTOR), were significantly phosphorylated in cisplatin-resistant wtEGFR NSCLC cell lines (H358R and A549R) than in their parental cells. Also, BEZ235 (dual phosphatidylinositol-3-kinase (PI3K)/mTOR inhibitor) significantly decreased the phosphorylation levels of these kinases/proteins, as detected by Western blot analysis. In H358R and A549R cells, the results of indirect immunofluorescence, single-cell gel electrophoresis, flow cytometry, methylthiazolyldiphenyl-tetrazolium bromide, clone formation assay, and scratch healing experiment showed that BEZ235 enhanced cisplatin-induced DNA damage and cell apoptosis, and effectively inhibited cellular proliferation/migration when combined with cisplatin. The data indicated that the abnormal activation of ATM/ATR/DNA-PKcs kinases and AKT/mTOR pathway might induce wtEGFR NSCLC cell resistance to cisplatin. The effects of the combination of BEZ235 and cisplatin suggested that BEZ235 should be considered as a combination therapy for patients with cisplatin-resistant wtEGFR NSCLC.

Cannabidiol Inhibits Tumorigenesis in Cisplatin-Resistant Non-Small Cell Lung Cancer via TRPV2.

Simple SummaryDrug resistance is the key factor contributing to the therapeutic failure of lung cancer and the deaths related to lung cancer. Our study demonstrated that small molecular weight non-psychotropic phytochemical, cannabidiol (CBD), inhibits growth and metastasis of drug-resistant non-small cell lung cancer cells (NSCLC) cells in-vitro and in-vivo. We further discovered that CBD mediates its anti-cancer effects in part via an ion channel receptor, TRPV2, present on lung adenocarcinoma. Moreover, we showed that CBD induces apoptosis of cisplatin-resistant cells by modulating oxidative stress pathways. Overall, these studies indicate that CBD could be used as a promising therapeutic strategy in TRPV2 expressing cisplatin-resistant NSCLC.Chemotherapy forms the backbone of current treatments for many patients with advanced non-small-cell lung cancer (NSCLC). However, the survival rate is low in these patients due to the development of drug resistance, including cisplatin resistance. In this study, we developed a novel strategy to combat the growth of cisplatin-resistant (CR) NSCLC cells. We have shown that treatment with the plant-derived, non-psychotropic small molecular weight molecule, cannabidiol (CBD), significantly induced apoptosis of CR NSCLC cells. In addition, CBD treatment significantly reduced tumor progression and metastasis in a mouse xenograft model and suppressed cancer stem cell properties. Further mechanistic studies demonstrated the ability of CBD to inhibit the growth of CR cell lines by reducing NRF-2 and enhancing the generation of reactive oxygen species (ROS). Moreover, we show that CBD acts through Transient Receptor Potential Vanilloid-2 (TRPV2) to induce apoptosis, where TRPV2 is expressed on human lung adenocarcinoma tumors. High expression of TRPV2 correlates with better overall survival of lung cancer patients. Our findings identify CBD as a novel therapeutic agent targeting TRPV2 to inhibit the growth and metastasis of this aggressive cisplatin-resistant phenotype in NSCLC.