Paclitaxel-resistant cancer cell-derived secretomes elicit ABCB1-associated docetaxel cross-resistance and escape from apoptosis through FOXO3a-driven glycolytic regulation

Novel sulfonamides unveiled as potent anti-lung cancer agents via tumor pyruvate kinase M2 activation

This rational pursuit led to the identification of a novel sulfonamide derivative as a potent anti-lung cancer (LC) compound. Considering these results, we synthesized 38 novel sulfonamide derivatives with diverse skeletal structures. In vitro cytotoxicity assays revealed a potent and selective antiproliferative effect against A549 cells after evaluating a panel of cancer cell lines. Compound 9b has emerged as a potent activator of tumor pyruvate kinase M2 (PKM2), a protein known to play a critical role in LC. Apoptosis assays and cell cycle analysis demonstrated early apoptosis and G2 phase arrest. In silico studies demonstrated interactions between compound 9b and the activator binding site of PKM2. Surface plasmon resonance (SPR) experiments strongly indicated that 9b has a high affinity (K d of 1.378 nM) for PKM2. Furthermore, the increase in reactive oxygen species and decrease in lactate concentration suggested that compound 9b has significant anticancer effects. Notably, the increase in particle size following treatment with 9b suggested the tetramerization of PKM2. This work provides insights that might advance efforts to develop effective non-platinum anticancer agents.

Key genes and molecular mechanisms related to Paclitaxel Resistance

Paclitaxel is commonly used to treat breast, ovarian, lung, esophageal, gastric, pancreatic cancer, and neck cancer cells. Cancer recurrence is observed in patients treated with paclitaxel due to paclitaxel resistance emergence. Resistant mechanisms are observed in cancer cells treated with paclitaxel, docetaxel, and cabazitaxel including changes in the target molecule β-tubulin of mitosis, molecular mechanisms that activate efflux drug out of the cells, and alterations in regulatory proteins of apoptosis. This review discusses new molecular mechanisms of taxane resistance, such as overexpression of genes like the multidrug resistance genes and EDIL3, ABCB1, MRP1, and TRAG-3/CSAG2 genes. Moreover, significant lncRNAs are detected in paclitaxel resistance, such as lncRNA H19 and cross-resistance between taxanes. This review contributed to discovering new treatment strategies for taxane resistance and increasing the responsiveness of cancer cells toward chemotherapeutic drugs.

CRISPR/Cas9-Mediated CtBP1 Gene Editing Enhances Chemosensitivity and Inhibits Metastatic Potential in Esophageal Squamous Cell Carcinoma Cells

Innovative therapeutic strategies for esophageal squamous cell carcinoma (ESCC) are urgently required due to the limited effectiveness of standard chemotherapies. C-Terminal Binding Protein 1 (CtBP1) has been implicated in various cancers, including ESCC. However, the precise expression patterns and functional roles of CtBP1 in ESCC remain inadequately characterized. In this study, we aimed to investigate CtBP1 expression and its role in the resistance of ESCC to paclitaxel, an effective chemotherapeutic agent. Western blotting and immunofluorescence were applied to assess CtBP1 expression in the TE-1 and KYSE-50 cell lines. We observed the marked expression of CtBP1, which was associated with enhanced proliferation, invasion, and metastasis in these cell lines. Further, we successfully generated paclitaxel resistant ESCC cell lines and conducted cell viability assays. We employed the CRISPR/Cas9 genome editing system to disable the CtBP1 gene in ESCC cell lines. Through the analysis of the drug dose-response curve, we assessed the sensitivity of these cell lines in different treatment groups. Remarkably, CtBP1-disabled cell lines displayed not only improved sensitivity but also a remarkable inhibition of proliferation, invasion, and metastasis. This demonstrates that CtBP1 may promote ESCC cell malignancy and confer paclitaxel resistance. In summary, our study opens a promising avenue for targeted therapies, revealing the potential of CtBP1 inhibition to enhance the effectiveness of paclitaxel treatment for the personalized management of ESCC.

Role of forkhead box proteins in regulation of doxorubicin and paclitaxel responses in tumor cells: A comprehensive review

Chemotherapy is one of the common first-line therapeutic methods in cancer patients. Despite the significant effects in improving the quality of life and survival of patients, chemo resistance is observed in a significant part of cancer patients, which leads to tumor recurrence and metastasis. Doxorubicin (DOX) and paclitaxel (PTX) are used as the first-line drugs in a wide range of tumors; however, DOX/PTX resistance limits their use in cancer patients. Considering the DOX/PTX side effects in normal tissues, identification of DOX/PTX resistant cancer patients is required to choose the most efficient therapeutic strategy for these patients. Investigating the molecular mechanisms involved in DOX/PTX response can help to improve the prognosis in cancer patients. Several cellular processes such as drug efflux, autophagy, and DNA repair are associated with chemo resistance that can be regulated by transcription factors as the main effectors in signaling pathways. Forkhead box (FOX) family of transcription factor has a key role in regulating cellular processes such as cell differentiation, migration, apoptosis, and proliferation. FOX deregulations have been associated with resistance to chemotherapy in different cancers. Therefore, we discussed the role of FOX protein family in DOX/PTX response. It has been reported that FOX proteins are mainly involved in DOX/PTX response by regulation of drug efflux, autophagy, structural proteins, and signaling pathways such as PI3K/AKT, NF-kb, and JNK. This review is an effective step in introducing the FOX protein family as the reliable prognostic markers and therapeutic targets in cancer patients.

The effect and mechanism of Zigui-Yichong-Fang on improving ovarian reserve in premature ovarian insufficiency by activating SIRT1/Foxo3a pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Zigui-Yichong-Fang (ZGYCF) is a traditional Chinese medicine prescription for the treatment of infertility. It is clinically used to regulate the hormone level of patients, improve ovarian reserve function and increase pregnancy rate. However, the exact mechanism of action is not yet clear.

AIMS OF THE STUDY

This study aims to explore the potential impact of ZGYCF on POI and its mechanism.

MATERIALS AND METHODS

Ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was used to identify the main compounds of ZGYCF. After confirming the therapeutic effect of ZGYCF on cyclophosphamide-induced POI mice, RNA sequencing (RNA-seq) analysis was carried out to explore the mechanism. Then, the effects of ZGYCF on SIRT1 deacetylated Foxo3a and apoptosis were verified from multiple perspectives by serum hormone level, mRNA validation, histomorphology and protein expression, acetylation modification and other experiments.

RESULTS

ZGYCF can improve the morphological changes of ovarian tissue in POI model mice, reduce the damage of primordial follicles and other follicles at all stages, and protect ovarian reserve. The results of transcriptome sequencing showed that the genes expression of PI3K signal and apoptosis signal pathway were increased in POI model mice; ZGYCF can up-regulate the expression of SIRT1 gene and the expression of estradiol, apoptosis inhibition and other signal pathway genes. In addition, ZGYCF can reduce follicular damage and ovarian cell apoptosis in POI model mice through activating the deacetylation of Foxo3a by SIRT1, and improve ovarian reserve function.

CONCLUSIONS

ZGYCF may improve ovarian reserve function of CTX-induced POI mice by activating SIRT1-mediated deacetylation of Foxo3a, and play a role in the treatment of POI.

Intratumor heterogeneity and cell secretome promote chemotherapy resistance and progression of colorectal cancer

The major underlying cause for the high mortality rate in colorectal cancer (CRC) relies on its drug resistance, to which intratumor heterogeneity (ITH) contributes substantially. CRC tumors have been reported to comprise heterogeneous populations of cancer cells that can be grouped into 4 consensus molecular subtypes (CMS). However, the impact of inter-cellular interaction between these cellular states on the emergence of drug resistance and CRC progression remains elusive. Here, we explored the interaction between cell lines belonging to the CMS1 (HCT116 and LoVo) and the CMS4 (SW620 and MDST8) in a 3D coculture model, mimicking the ITH of CRC. The spatial distribution of each cell population showed that CMS1 cells had a preference to grow in the center of cocultured spheroids, while CMS4 cells localized at the periphery, in line with observations in tumors from CRC patients. Cocultures of CMS1 and CMS4 cells did not alter cell growth, but significantly sustained the survival of both CMS1 and CMS4 cells in response to the front-line chemotherapeutic agent 5-fluorouracil (5-FU). Mechanistically, the secretome of CMS1 cells exhibited a remarkable protective effect for CMS4 cells against 5-FU treatment, while promoting cellular invasion. Secreted metabolites may be responsible for these effects, as demonstrated by the existence of 5-FU induced metabolomic shifts, as well as by the experimental transfer of the metabolome between CMS1 and CMS4 cells. Overall, our results suggest that the interplay between CMS1 and CMS4 cells stimulates CRC progression and reduces the efficacy of chemotherapy.

KIF14 mediates cabazitaxel-docetaxel cross-resistance in advanced prostate cancer by promoting AKT phosphorylation

Docetaxel is a first-line chemotherapy drug for castration-resistant prostate cancer (CRPC); yet, some CRPC patients develop docetaxel drug resistance. Cabazitaxel is approved in the post-docetaxel treatment setting. However, recent studies suggested cross-resistance between the development of drug resistance and current treatments. In this study, we used docetaxel-resistant cell lines DU145/DTX50 and PC-3/DTX30 to measure the responses to cabazitaxel. Our findings demonstrated that docetaxel resistance could lead to cross-resistance to cabazitaxel. After docetaxel-resistant cells were treated with cabazitaxel, transcriptome analysis was performed, and the results were analyzed in combination with survival analysis and correlation analysis with Gleason score to screen the cross-resistance genes. The continuously increased expression of kinesin family member 14 (KIF14) was identified as the main cause of cross-resistance to cabazitaxel in docetaxel-resistant cells. Silencing the expression of KIF14 could restore the sensitivity of resistant PCa cells to docetaxel and cabazitaxel, attenuate proliferation and promote apoptosis of the resistant PCa cells. Notably, the depressed expression of KIF14 inhibited the phosphorylation of Akt located downstream. In summary, KIF14 mediates the cross-resistance between docetaxel and cabazitaxel, and targeting KIF14 could be an effective measurement for reversing docetaxel or cabazitaxel chemotherapy failure or enhancing the anti-tumor effects of docetaxel or cabazitaxel.

The prognostic gene CRABP2 affects drug sensitivity by regulating docetaxel-induced apoptosis in breast invasive carcinoma: A pan-cancer analysis

Cellular retinoic acid-binding protein 2 (CRABP2), a specific transporter of retinoic acid, has been shown to have an important biological role in human cancers. However, due to the substantial variability among different tumors, the role of CRABP2 remains uncertain and has not yet been subjected to systematic analysis. Utilizing The Cancer Genome Atlas (TCGA), Genotype-Tissue Expression (GTEx), Clinical Proteomic Tumor Analysis Consortium (CPTAC), Human Protein Atlas (HPA), Gene Expression Profiling Interactive Analysis 2 (GEPIA2), Kaplan-Meier Plotter, Biomarker Exploration of Solid Tumors (BEST), Cancer Cell Line Encyclopedia (CCLE), Receiver Operating Characteristic plotter (ROC plotter), and other online public tools, expression levels of CRABP2 in breast invasive carcinoma (BRCA), lung adenocarcinoma (LUAD), and ovarian serous cystadenocarcinoma (OV) were found to be significantly greater than those in adjacent normal tissues, suggesting a correlation to poor prognosis. Among the three, CRABP2 expression in BRCA was most closely associated with clinical prognosis. In a study of docetaxel-treated BRCA patients, CRABP2 expression was significantly higher in the drug-resistant group. Colony formation and flow cytometry analysis were used to further investigate the relationship between CRABP2 and docetaxel sensitivity in BRCA cells MDA-MB-231and BT549. The knockdown of CRABP2 expression significantly reduced cell growth and increased sensitivity to the chemotherapeutic agent docetaxel in BRCA cells. Furthermore, CRABP2 knockdown augmented docetaxel-induced apoptosis. Molecular docking using SwissDock tool revealed that CRABP2 had a greater binding affinity to docetaxel than docetaxel-targeted proteins. This research provides an insight into the expression and prognostic potential of CRABP2 in cancers and suggests that CRABP2 may control docetaxel sensitivity in BRCA cells through apoptosis, warranting further investigation.

Role of lncRNAs in the pathogenic mechanism of human decreased ovarian reserve

Decreased ovarian reserve (DOR) is defined as a decrease in the quality and quantity of oocytes, which reduces ovarian endocrine function and female fertility. The impaired follicular development and accelerated follicle atresia lead to a decrease in the number of follicles, while the decline of oocyte quality is related to the disorder of DNA damage-repair, oxidative stress, and the dysfunction of mitochondria. Although the mechanism of DOR is still unclear, recent studies have found that long non-coding RNA (lncRNA) as a group of functional RNA molecules participate in the regulation of ovarian function, especially in the differentiation, proliferation and apoptosis of granulosa cells in the ovary. LncRNAs participate in the occurrence of DOR by affecting follicular development and atresia, the synthesis and secretion of ovarian hormones. This review summarizes current research on lncRNAs associated with DOR and reveals the potential underlying mechanisms. The present study suggests that lncRNAs could be considered as prognostic markers and treatment targets for DOR.

Antineoplastic multi-drug chemotherapy to sensitize tumors triggers multi-drug resistance and inhibits efficiency of maintenance treatment inglioblastoma cells

Combinations of the well-known antineoplastic agents 5-fluorouracil (5-Fu), cisplatin, and paclitaxel are employed to increase radiotherapy/immunotherapy efficacy against persistent and resistant tumors. However, data remains needed on the hormetic, chronic, and long-term side effects of these aggressive combination chemotherapies. Here we investigated cellular and molecular responses associated with these combined agents, and their potential to induce multi-drug resistance against the temozolomide (TMZ) and etoposide (EP) used in glioblastoma maintenance treatment. We analyzed resistance and survival signals in U87 MG cells using molecular probes, fluorescent staining, qRT-PCR, and immunoblot. Repeated treatment with combined 5-Fu, cisplatin, and paclitaxel induced cross-resistance against TMZ and EP. Resistant cells exhibited elevated gene/protein expression of MRP1/ABCC1, ABCC2, BRCP/ABCG2, and GST. Moreover, they managed oxidative stress, cell cycle, apoptosis, and autophagy signaling to ensure survival. In these groups TMZ and etoposide efficiency dramatically reduced. Our result suggests that combined high-dose treatments of classical antineoplastic agents to sensitize tumors may trigger multi-drug resistance and inhibit maintenance treatment. When deciding on antineoplastic combination therapy for persistent/resistant glioblastoma, we recommend analyzing the long-term hormetic and chronic effects on cross-resistance and multi-drug resistance in primary cell cultures from patients. See also the Graphical Abstract(Fig. 1).

Cross-Resistance Among Sequential Cancer Therapeutics: An Emerging Issue

Over the past two decades, cancer treatment has benefited from having a significant increase in the number of targeted drugs approved by the United States Food and Drug Administration. With the introduction of targeted therapy, a great shift towards a new era has taken place that is characterized by reduced cytotoxicity and improved clinical outcomes compared to traditional chemotherapeutic drugs. At present, targeted therapies and other systemic anti-cancer therapies available (immunotherapy, cytotoxic, endocrine therapies and others) are used alone or in combination in different settings (neoadjuvant, adjuvant, and metastatic). As a result, it is not uncommon for patients affected by an advanced malignancy to receive subsequent anti-cancer therapies. In this challenging complexity of cancer treatment, the clinical pathways of real-life patients are often not as direct as predicted by standard guidelines and clinical trials, and cross-resistance among sequential anti-cancer therapies represents an emerging issue. In this review, we summarize the main cross-resistance events described in the diverse tumor types and provide insight into the molecular mechanisms involved in this process. We also discuss the current challenges and provide perspectives for the research and development of strategies to overcome cross-resistance and proceed towards a personalized approach.

The IRENA lncRNA converts chemotherapy-polarized tumor-suppressing macrophages to tumor-promoting phenotypes in breast cancer

Although chemotherapy can stimulate antitumor immunity by inducing interferon (IFN) response, the functional role of tumor-associated macrophages in this scenario remains unclear. Here, we found that IFN-activated proinflammatory macrophages after neoadjuvant chemotherapy enhanced antitumor immunity but promoted cancer chemoresistance. Mechanistically, IFN induced expression of cytoplasmic long noncoding RNA IFN-responsive nuclear factor-κB activator (IRENA) in macrophages, which triggered nuclear factor-κB signaling via dimerizing protein kinase R and subsequently increased production of protumor inflammatory cytokines. By constructing macrophage-conditional IRENA-knockout mice, we found that targeting IRENA in IFN-activated macrophages abrogated their protumor effects, while retaining their capacity to enhance antitumor immunity. Clinically, IRENA expression in post-chemotherapy macrophages was associated with poor patient survival. These findings indicate that lncRNA can determine the dichotomy of inflammatory cells on cancer progression and antitumor immunity and suggest that targeting IRENA is an effective therapeutic strategy to reversing tumor-promoting inflammation.

Melatonin: Regulation of Prion Protein Phase Separation in Cancer Multidrug Resistance

The unique ability to adapt and thrive in inhospitable, stressful tumor microenvironments (TME) also renders cancer cells resistant to traditional chemotherapeutic treatments and/or novel pharmaceuticals. Cancer cells exhibit extensive metabolic alterations involving hypoxia, accelerated glycolysis, oxidative stress, and increased extracellular ATP that may activate ancient, conserved prion adaptive response strategies that exacerbate multidrug resistance (MDR) by exploiting cellular stress to increase cancer metastatic potential and stemness, balance proliferation and differentiation, and amplify resistance to apoptosis. The regulation of prions in MDR is further complicated by important, putative physiological functions of ligand-binding and signal transduction. Melatonin is capable of both enhancing physiological functions and inhibiting oncogenic properties of prion proteins. Through regulation of phase separation of the prion N-terminal domain which targets and interacts with lipid rafts, melatonin may prevent conformational changes that can result in aggregation and/or conversion to pathological, infectious isoforms. As a cancer therapy adjuvant, melatonin could modulate TME oxidative stress levels and hypoxia, reverse pH gradient changes, reduce lipid peroxidation, and protect lipid raft compositions to suppress prion-mediated, non-Mendelian, heritable, but often reversible epigenetic adaptations that facilitate cancer heterogeneity, stemness, metastasis, and drug resistance. This review examines some of the mechanisms that may balance physiological and pathological effects of prions and prion-like proteins achieved through the synergistic use of melatonin to ameliorate MDR, which remains a challenge in cancer treatment.

Circular RNA FOXO3 accelerates glycolysis and improves cisplatin sensitivity in lung cancer cells via the miR-543/Foxo3 axis

Non-small cell lung cancer (NSCLC) is the most common cause of cancer-associated mortality worldwide. Our previous study revealed that circular RNA (circRNA)-FOXO3 is highly expressed in lung cancer and inhibits cell proliferation. However, to the best of our knowledge, at present, no study has focused on the specific mechanism of circRNA-FOXO3 in drug resistance. Therefore, the present study aimed to provide novel perspectives on the role of circRNA-FOXO3 in cisplatin (DDP) resistance in NSCLC. A Cell Counting Kit-8 assay was used to determine the viability of cells overexpressed with circRNA-FOXO3 and under DDP treatment. Glycolysis was analyzed by measuring glucose consumption and lactate production. The interaction of circRNA-FOXO3, microRNA 543 (miR-543) and Foxo3 was confirmed using a dual-luciferase reporter assay. It was revealed that circRNA-FOXO3 improved cell sensitivity to DDP and repressed glycolysis in DDP-sensitive and DDP-resistant NSCLC cells. Bioinformatics analysis, luciferase reporter assays, quantitative PCR and RNA pull-down assays were employed to verify the binding of circRNA-FOXO3 to miR-543. Functionally, inhibition of miR-543 could sensitize NSCLC cells to DDP, and overexpression of miR-543 at least partially abolished the circRNA-FOXO3-induced decrease in chemoresistance. Furthermore, it was revealed that Foxo3 was a direct target of miR-543. Notably, the inhibitory action of miR-543 silencing on DDP resistance and glycolysis was reversed by overexpression of Foxo3 in DDP-sensitive and DDP-resistant NSCLC cells. In conclusion, the present study demonstrated that circRNA-FOXO3 promoted DDP sensitivity in NSCLC cells by regulating the miR-543/Foxo3 axis-mediated glycolysis balance. The present findings may provide novel perspectives for the treatment of patients with NSCLC resistant to DDP.

Synergistic Antitumor Activity of SH003 and Docetaxel via EGFR Signaling Inhibition in Non-Small Cell Lung Cancer

Epidermal growth factor receptor (EGFR) is overexpressed in lung cancer patients. Despite treatment with various EGFR tyrosine kinase inhibitors, recurrence and metastasis of lung cancer are inevitable. Docetaxel (DTX) is an effective conventional drug that is used to treat various cancers. Several researchers have studied the use of traditional herbal medicine in combination with docetaxel, to improve lung cancer treatment. SH003, a novel herbal mixture, exerts anticancer effects in different cancer cell types. Here, we aimed to investigate the apoptotic and anticancer effects of SH003 in combination with DTX, in human non-small-cell lung cancer (NSCLC). SH003, with DTX, induced apoptotic cell death, with increased expression of cleaved caspases and cleaved poly (ADP-ribose) polymerase in NSCLC cells. Moreover, SH003 and DTX induced the apoptosis of H460 cells via the suppression of the EGFR and signal transducer and activator of transcription 3 (STAT3) signaling pathways. In H460 tumor xenograft models, the administration of SH003 or docetaxel alone diminished tumor growth, and their combination effectively killed cancer cells, with increased expression of apoptotic markers and decreased expression of p-EGFR and p-STAT3. Collectively, the combination of SH003 and DTX may be a novel anticancer strategy to overcome the challenges that are associated with conventional lung cancer therapy.

MiR-223-3p targets FOXO3a to inhibit radiosensitivity in prostate cancer by activating glycolysis

AIMS

The incidence and detection rate of prostate cancer in China have been increasing in recent years. Radiotherapy is the ideal treatment for non-metastatic prostate cancer (PCa), but the effectiveness of radiotherapy is greatly discounted due to radio resistance. Therefore, relieving the radiotherapy resistance of PCa is key to improve the clinical efficacy of PCA.

MAIN METHODS

Cell proliferation was estimated using the MTT and clone formation assays. Cell apoptosis was estimated using the Annexin V-FITC/propidium iodide (PI) staining assay. Glucose uptake and lactose and ATP production were used to detect glycolysis.

KEY FINDINGS

miR-223-3p was significantly upregulated in clinically collected urine samples and PCa cells with low radiosensitivity. Enhancing miR-223-3p reduced radiosensitivity further, while inhibiting miR-223-3p improved the radiosensitivity of PC3 and LNCaP cells. Importantly, miR-223-3p regulated radiosensitivity by enhancing cell glycolysis. FOXO3a was a key target of miRNA-223-3p regulating glycolysis and radiosensitivity. Overexpression of FOXO3a abated the glycolysis level and alleviated the radioresistance caused by enhancing miR-223-3p to a certain extent.

SIGNIFICANCE

This is novel research on the role of miR-223-3p in promoting radiotherapy resistance of PCa cells by activating glycolysis. This approach provides a new perspective and ideas for alleviating radiotherapy resistance of PCa cells.

HMGB1 enhances chemotherapy resistance in multiple myeloma cells by activating the nuclear factor-κB pathway

Chemotherapy resistance is a main obstacle in the clinical chemotherapeutic treatment of multiple myeloma (MM). High-mobility group box 1 (HMGB1) has been revealed to be associated with the sensitivity of MM cells to chemotherapy, but how HMGB1 regulates chemotherapy resistance in MM has yet to be fully elucidated. In the present study, the exact molecular mechanism underlying HMGB1-mediated drug resistance in MM was explored using three chemotherapy-resistant MM cells (RPMI8226/ADR, RPMI8226/BOR and RPMI8226/DEX) that were successfully established. Reverse transcription-quantitative polymerase chain reaction revealed that the three chemotherapy-resistant MM cells exhibited a higher release of HMGB1 compared with the parental RPMI8226 cells. Interference with endogenous HMGB1 increased the sensitivity of drug-resistant MM cells to chemotherapy, which was supported by the low IC₅₀ value and the enlargement of cell apoptosis. Furthermore, short hairpin (sh)RNA-transfected MM cells showed an obvious elevation in phosphorylated (p)-IKKα/β, p-IκBα and p-p65 in whole cell lysate and/or nucleus, and treatment of nuclear factor (NF)-κB activator reversed the effect of shHMGB1-mediated cell viability and apoptosis in MM cells. In conclusion, HMGB1 regulates drug resistance in MM cells by regulating NF-κB signaling pathway, suggesting that HMGB1 has the potential to serve as a target for MM treatment.

Forkhead box protein O3a promotes glioma cell resistance to temozolomide by regulating matrix metallopeptidase and β-catenin

Glioblastoma multiforme (GBM) is the most common type of malignant brain tumor. GBM is currently treated with temozolomide (TMZ), although patients often exhibit resistance to this agent. Although several mechanisms underlying the resistance of GBM to TMZ have been identified, the combination of these mechanisms is not sufficient to fully account for this phenomenon. Our previous study demonstrated that knocking down the Forkhead box protein O3a (FoxO3a) gene, a member of the FoxO subfamily of transcription factors, resulted in glioma cell sensitization to TMZ, accompanied by reduced levels of nuclear β-catenin. The aim of the present study was to specify how FoxO3a and β-catenin are implicated in glioma cell TMZ resistance. Using the U87 and U251 parental cell lines (also designated as sensitive cell lines) and corresponding resistant cell lines (U87-TR and U251-TR, generated by repeated TMZ treatments), coupled with a combined knockdown/overexpression strategy, it was revealed that FoxO3a or β-catenin overexpression in TMZ-treated U87 and U251 cells markedly increased cellular proliferation; co-expression of both FoxO3a and β-catenin resulted in the highest increase. Knockdown of either FoxO3a or β-catenin in U87-TR and U251-TR cells led to a significant decrease in cell viability, which was rescued by the re-expression of FoxO3a in FoxO3a-knockdown cells. Subsequent experiments demonstrated that, in U87-TR and U251-TR cells, FoxO3a knockdown significantly reduced the protein levels of matrix metallopeptidase (MMP)9, while overexpression of FoxO3a in U87 and U251 cells enhanced the nuclear accumulation of β-catenin, concomitantly with an increase in MMP9 levels. Furthermore, MMP9 knockdown markedly reduced the levels of nuclear β-catenin. Collectively, the findings of the present study suggest that FoxO3a may regulate the nuclear accumulation of β-catenin by modulating MMP9 expression, thereby rendering glioblastoma cells resistant to TMZ, and may provide unique molecular insights into the mechanisms underlying the development of TMZ resistance in GBM.

Taxanes in cancer treatment: Activity, chemoresistance and its overcoming

Since 1984, when paclitaxel was approved by the FDA for the treatment of advanced ovarian carcinoma, taxanes have been widely used as microtubule-targeting antitumor agents. However, their historic classification as antimitotics does not describe all their functions. Indeed, taxanes act in a complex manner, altering multiple cellular oncogenic processes including mitosis, angiogenesis, apoptosis, inflammatory response, and ROS production. On the one hand, identification of the diverse effects of taxanes on oncogenic signaling pathways provides opportunities to apply these cytotoxic drugs in a more rational manner. On the other hand, this may facilitate the development of novel treatment modalities to surmount anticancer drug resistance. In the latter respect, chemoresistance remains a major impediment which limits the efficacy of antitumor chemotherapy. Taxanes have shown impact on key molecular mechanisms including disruption of mitotic spindle, mitosis slippage and inhibition of angiogenesis. Furthermore, there is an emerging contribution of cellular processes including autophagy, oxidative stress, epigenetic alterations and microRNAs deregulation to the acquisition of taxane resistance. Hence, these two lines of findings are currently promoting a more rational and efficacious taxane application as well as development of novel molecular strategies to enhance the efficacy of taxane-based cancer treatment while overcoming drug resistance. This review provides a general and comprehensive picture on the use of taxanes in cancer treatment. In particular, we describe the history of application of taxanes in anticancer therapeutics, the synthesis of the different drugs belonging to this class of cytotoxic compounds, their features and the differences between them. We further dissect the molecular mechanisms of action of taxanes and the molecular basis underlying the onset of taxane resistance. We further delineate the possible modalities to overcome chemoresistance to taxanes, such as increasing drug solubility, delivery and pharmacokinetics, overcoming microtubule alterations or mitotic slippage, inhibiting drug efflux pumps or drug metabolism, targeting redox metabolism, immune response, and other cellular functions.

Hypermethylation-mediated downregulation of lncRNA PVT1 promotes granulosa cell apoptosis in premature ovarian insufficiency via interacting with Foxo3a

Long noncoding RNA PVT1 is involved in the progression of female gynecological cancers. However, the role of PVT1 in ovarian granulosa cell apoptosis-mediated premature ovarian insufficiency (POI) remains unclear. This study aims to elucidate the role of PVT1 in ovarian granulosa cell apoptosis-mediated POI. The expression of PVT1 was compared between ovarian tissues from POI patients and normal controls. The methylation level in the PVT1 promoter region was detected by methylation-specific polymerase chain reaction. The interaction between PVT1 and forkhead box class O3A (Foxo3a) was confirmed by RNA pull-down and RNA immunoprecipitation assays. Granulosa cell apoptosis was detected using flow cytometry. The effect of PVT1 on transcription activity of Foxo3a was detected by luciferase reporter assay. The expression of PVT1 was low in the POI ovarian tissues compared with the controls, and such a low expression was related to the hypermethylation of the PVT1 promoter. PVT1 was localized in both the cytoplasm and the nucleus of granulosa cells. We determined that PVT1 could bind with Foxo3a and that downregulating PVT1 by small interfering RNAs inhibited Foxo3a phosphorylation by promoting SCP4-mediated Foxo3a dephosphorylation, resulting in an increase in Foxo3a transcription activity. Moreover, downregulating PVT1 promoted granulosa cell apoptosis by increasing the Foxo3a protein levels. An in vivo experiment showed that the injection of PVT1 overexpressing vectors restored the ovarian function in POI mice. Hypermethylation-induced downregulation of PVT1 promotes granulosa cell apoptosis in POI by inhibiting Foxo3a phosphorylation and increases the Foxo3a transcription activity.

New Insights into Therapy-Induced Progression of Cancer

The malignant tumor is a complex heterogeneous set of cells functioning in a no less heterogeneous microenvironment. Like any dynamic system, cancerous tumors evolve and undergo changes in response to external influences, including therapy. Initially, most tumors are susceptible to treatment. However, remaining cancer cells may rapidly reestablish the tumor after a temporary remission. These new populations of malignant cells usually have increased resistance not only to the first-line agent, but also to the second- and third-line drugs, leading to a significant decrease in patient survival. Multiple studies describe the mechanism of acquired therapy resistance. In past decades, it became clear that, in addition to the simple selection of pre-existing resistant clones, therapy induces a highly complicated and tightly regulated molecular response that allows tumors to adapt to current and even subsequent therapeutic interventions. This review summarizes mechanisms of acquired resistance, such as secondary genetic alterations, impaired function of drug transporters, and autophagy. Moreover, we describe less obvious molecular aspects of therapy resistance in cancers, including epithelial-to-mesenchymal transition, cell cycle alterations, and the role of intercellular communication. Understanding these molecular mechanisms will be beneficial in finding novel therapeutic approaches for cancer therapy.

HMGB1 release promotes paclitaxel resistance in castration-resistant prostate cancer cells via activating c-Myc expression

Paclitaxel (PTX) is one of standard chemotherapy drug for patients with metastatic castration-resistant prostate cancer (mCRPC). However, PTX resistance leads to treatment failures, for which the underlying molecular mechanisms remain exclusive. In this study, we reported that PTX-induced constant HMGB1 expression and release confers to PTX resistance in mCRPC cells via activating and sustaining c-Myc signaling. PTX upregulated HMGB1 expression and triggered its release in human mCRPC cells. Silencing HMGB1 by RNAi and blocking HMGB1 release by glycyrrhizin or HMGB1 neutralizing antibody sensitized the response of PTX-resistant mCRPC cells to PTX. Release HMGB1 activated c-Myc expression. Inhibiting c-Myc expression by RNAi or c-MyC inhibitor significantly enhance the sensitivity of PTX-resistant CRPC cells to PTX. Therefore, HMGB1/c-Myc axis is critical in the development of PTX resistance, and targeting HMGB1/c-Myc axis would counteract PTX resistance in mCRPC cells.

Polymorphisms in Glycolysis-Related Genes Are Associated with Clinical Outcomes of Paclitaxel-Cisplatin Chemotherapy in Non-Small Cell Lung Cancer

OBJECTIVE

This study was conducted to investigate whether polymorphisms in glycolysis-related genes are associated with clinical outcomes of patients with advanced-stage non-small cell lung cancer (NSCLC) undergoing chemotherapy.

METHODS

A total of 377 patients with NSCLC were enrolled. Sixty-five single-nucleotide polymorphisms in 26 genes involved in the glycolytic pathway were evaluated. The associations of the variants with the chemotherapy response and overall survival (OS) were analyzed.

RESULTS

Among the 65 variants investigated, PFKL rs2073436C>G and GPI rs7248411C>G significantly correlated with clinical outcomes after chemotherapy in multivariate analyses. PFKL rs2073436C>G was significantly associated with both a worse response to chemotherapy (adjusted odds ratio [aOR] = 0.64, 95% CI = 0.45-0.90, p = 0.01) and a worse OS (adjusted hazard ratio [aHR] = 1.35, 95% CI = 1.14-1.61, p = 0.001). GPI rs7248411C>G was significantly associated with both a better chemotherapy response (aOR = 1.58, 95% CI = 1.07-2.23, p = 0.02) and a better OS (aHR = 0.80, 95% CI = 0.66-0.98, p = 0.03). When stratified by tumor histology, PFKL rs2073436C>G was significantly associated with OS only in squamous cell carcinoma, whereas GPI rs7248411C>G exhibited a significant association with the chemotherapy response and OS only in adenocarcinoma.

CONCLUSION

This result suggests that the PFKL rs2073436C>G and GPI rs7248411C>G are useful for predicting the clinical outcome of first-line paclitaxel-cisplatin chemotherapy in NSCLC.

Prior acquired resistance to paclitaxel relays diverse EGFR-targeted therapy persistence mechanisms

Secondary drug resistance stems from dynamic clonal evolution during the development of a prior primary resistance. This collateral type of resistance is often a characteristic of cancer recurrence. Yet, mechanisms that drive this collateral resistance and their drug-specific trajectories are still poorly understood. Using resistance selection and small-scale pharmacological screens, we find that cancer cells with primary acquired resistance to the microtubule-stabilizing drug paclitaxel often develop tolerance to epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs), leading to formation of more stable resistant cell populations. We show that paclitaxel-resistant cancer cells follow distinct selection paths under EGFR-TKIs by enriching the stemness program, developing a highly glycolytic adaptive stress response, and rewiring an apoptosis control pathway. Collectively, our work demonstrates the alterations in cellular state stemming from paclitaxel failure that result in collateral resistance to EGFR-TKIs and points to new exploitable vulnerabilities during resistance evolution in the second-line treatment setting.

What sustains the multidrug resistance phenotype beyond ABC efflux transporters? Looking beyond the tip of the iceberg

Identification of multidrug (MDR) efflux transporters that belong to the ATP-Binding Cassette (ABC) superfamily, represented an important breakthrough for understanding cancer multidrug resistance (MDR) and its possible overcoming. However, recent data indicate that drug resistant cells have a complex intracellular physiology that involves constant changes in energetic and oxidative-reductive metabolic pathways, as well as in the molecular circuitries connecting mitochondria, endoplasmic reticulum (ER) and lysosomes. The aim of this review is to discuss the key molecular mechanisms of cellular reprogramming that induce and maintain MDR, beyond the presence of MDR efflux transporters. We specifically highlight how cancer cells characterized by high metabolic plasticity - i.e. cells able to shift the energy metabolism between glycolysis and oxidative phosphorylation, to survive both the normoxic and hypoxic conditions, to modify the cytosolic and mitochondrial oxidative-reductive metabolism, are more prone to adapt to exogenous stressors such as anti-cancer drugs and acquire a MDR phenotype. Similarly, we discuss how changes in mitochondria dynamics and mitophagy rates, changes in proteome stability ensuring non-oncogenic proteostatic mechanisms, changes in ubiquitin/proteasome- and autophagy/lysosome-related pathways, promote the cellular survival under stress conditions, along with the acquisition or maintenance of MDR. After dissecting the complex intracellular crosstalk that takes place during the development of MDR, we suggest that mapping the specific adaptation pathways underlying cell survival in response to stress and targeting these pathways with potent pharmacologic agents may be a new approach to enhance therapeutic efficacy against MDR tumors.

Insect ATP-Binding Cassette (ABC) Transporters: Roles in Xenobiotic Detoxification and Bt Insecticidal Activity

ATP-binding cassette (ABC) transporters, a large class of transmembrane proteins, are widely found in organisms and play an important role in the transport of xenobiotics. Insect ABC transporters are involved in insecticide detoxification and Bacillus thuringiensis (Bt) toxin perforation. The complete ABC transporter is composed of two hydrophobic transmembrane domains (TMDs) and two nucleotide binding domains (NBDs). Conformational changes that are needed for their action are mediated by ATP hydrolysis. According to the similarity among their sequences and organization of conserved ATP-binding cassette domains, insect ABC transporters have been divided into eight subfamilies (ABCA–ABCH). This review describes the functions and mechanisms of ABC transporters in insecticide detoxification, plant toxic secondary metabolites transport and insecticidal activity of Bt toxin. With improved understanding of the role and mechanisms of ABC transporter in resistance to insecticides and Bt toxins, we can identify valuable target sites for developing new strategies to control pests and manage resistance and achieve green pest control.

The Dominant Role of Forkhead Box Proteins in Cancer

Forkhead box (FOX) proteins are multifaceted transcription factors that are significantly implicated in cancer, with various critical roles in biological processes. Herein, we provide an overview of several key members of the FOXA, FOXC, FOXM1, FOXO and FOXP subfamilies. Important pathophysiological processes of FOX transcription factors at multiple levels in a context-dependent manner are discussed. We also specifically summarize some major aspects of FOX transcription factors in association with cancer research such as drug resistance, tumor growth, genomic alterations or drivers of initiation. Finally, we suggest that targeting FOX proteins may be a potential therapeutic strategy to combat cancer.

Drug Resistance in Non-Small Cell Lung Cancer: A Potential for NOTCH Targeting?

Drug resistance is a major cause for therapeutic failure in non-small cell lung cancer (NSCLC) leading to tumor recurrence and disease progression. Cell intrinsic mechanisms of resistance include changes in the expression of drug transporters, activation of pro-survival, and anti-apoptotic pathways, as well as non-intrinsic influences of the tumor microenvironment. It has become evident that tumors are composed of a heterogeneous population of cells with different genetic, epigenetic, and phenotypic characteristics that result in diverse responses to therapy, and underlies the emergence of resistant clones. This tumor heterogeneity is driven by subpopulations of tumor cells termed cancer stem cells (CSCs) that have tumor-initiating capabilities, are highly self-renewing, and retain the ability for multi-lineage differentiation. CSCs have been identified in NSCLC and have been associated with chemo- and radiotherapy resistance. Stem cell pathways are frequently deregulated in cancer and are implicated in recurrence after treatment. Here, we focus on the NOTCH signaling pathway, which has a role in stem cell maintenance in non-squamous non-small lung cancer, and we critically assess the potential for targeting the NOTCH pathway to overcome resistance to chemotherapeutic and targeted agents using both preclinical and clinical evidence.

Variable Cell Line Pharmacokinetics Contribute to Non-Linear Treatment Response in Heterogeneous Cell Populations

We develop a combined experimental-mathematical framework to investigate heterogeneity in the context of breast cancer treated with doxorubicin. We engineer a cell line to over-express the multi-drug resistance 1 protein (MDR1), an ATP-dependent pump that effluxes intracellular drug. Co-culture experiments mixing the MDR1-overexpressing line with its parental line are evaluated via fluorescence microscopy. To quantify the impact of population heterogeneity on therapy response, these data are analyzed with a coupled pharmacokinetics/pharmacodynamics model. The proliferation and death rates of each line vary with co-culture condition (the relative fraction of each cell line at the time of seeding). For example, the death rate in the parental line under low-dose doxorubicin treatment is increased from 0.64 (± 0.22) × 10^-2 to 1.46 (± 0.58) × 10^-2 h^-1 with increasing fractions of MDR1-overexpressing cells. The growth rate of the MDR1-overexpressing line increases 29% as its relative fraction is decreased. Simulations of the pharmacokinetics/pharmacodynamics model suggest increased efflux from MDR1-overexpressing cells contributes to the increased death rate in the parental cells. Experimentally, the death rate of parental cells is constant across co-culture conditions under co-treatment with an MDR1 inhibitor. These data indicate that intercellular pharmacokinetic variability should be considered in analyzing treatment response in heterogeneous populations.

Pharmacological treatment with inhibitors of nuclear export enhances the antitumor activity of docetaxel in human prostate cancer

Background and aims

Docetaxel (DTX) modestly increases patient survival of metastatic castration-resistant prostate cancer (mCRPC) due to insurgence of pharmacological resistance. Deregulation of Chromosome Region Maintenance (CRM-1)/ exportin-1 (XPO-1)-mediated nuclear export may play a crucial role in this phenomenon.

Material and methods

Here, we evaluated the effects of two Selective Inhibitor of Nuclear Export (SINE) compounds, selinexor (KPT-330) and KPT-251, in association with DTX by using 22rv1, PC3 and DU145 cell lines with their. DTX resistant derivatives.

Results and conclusions

We show that DTX resistance may involve overexpression of β-III tubulin (TUBB3) and P-glycoprotein as well as increased cytoplasmic accumulation of Foxo3a. Increased levels of XPO-1 were also observed in DTX resistant cells suggesting that SINE compounds may modulate DTX effectiveness in sensitive cells as well as restore the sensitivity to DTX in resistant ones. Pretreatment with SINE compounds, indeed, sensitized to DTX through increased tumor shrinkage and apoptosis by preventing DTX-induced cell cycle arrest. Basally SINE compounds induce FOXO3a activation and nuclear accumulation increasing the expression of FOXO-responsive genes including p21, p27 and Bim causing cell cycle arrest. SINE compounds-catenin and survivin supporting apoptosis. βdown-regulated Cyclin D1, c-myc, Nuclear sequestration of p-Foxo3a was able to reduce ABCB1 and TUBB3 H2AX levels, prolonged γ expression. Selinexor treatment increased DTX-mediated double strand breaks (DSB), and reduced the levels of DNA repairing proteins including DNA PKc and Topo2A. Our results provide supportive evidence for the therapeutic use of SINE compounds in combination with DTX suggesting their clinical use in mCRPC patients.

Combined Inhibitions of Glycolysis and AKT/autophagy Can Overcome Resistance to EGFR-targeted Therapy of Lung Cancer

Efficacy of EGFR-targeted tyrosine kinase inhibitors (TKIs), such as erlotinib, to treat human non-small cell lung cancers (NSCLCs) with activating mutations in EGFR is not persistent due to drug resistance. Reprogramming in energy (especially glucose) metabolism plays an important role in development and progression of acquired resistance in cancer cells. We hypothesize that glucose metabolism in EGFR-TKI sensitive HCC827 cells and erlotinib-resistant sub-line of HCC827 (which we name it as erlotinib-resistant 6, ER6 cells in this study) is different and targeting glucose metabolism might be a treatment strategy for erlotinib-resistant NSCLCs. In this study, we found increased glucose uptakes, significant increase in glycolysis rate and overexpression of glucose transporter 1 in ER6 cells compared to its parental cells HCC827. We also found AKT and autophagy of ER6 cells were more activated than HCC827 cells after glucose starvation. Combining glucose deprivation and AKT or autophagy inhibitor could synergize and overcome the acquired resistance against EGFR-targeted therapy for NSCLCs. Our data suggest that the combinations of inhibitors of AKT or autophagy together with glucose deprivation could be novel treatment strategies for NSCLC with acquired resistance to targeted therapy.

Paraoxonase-1 (PON1) induces metastatic potential and apoptosis escape via its antioxidative function in lung cancer cells

Paraoxonase-1 (PON1) gene polymorphisms have been closely associated with the development of advanced cancers while PON1 secretion to the serum is linked with inhibition of oxidized high-density lipoprotein by its antioxidative function. Our group previously demonstrated that post-translational modification of serum PON1 in form of fucosylated PON1 is a potential biomarker of small cell lung cancer. Here, we interrogated the role of PON1 in the pathobiology of lung cancer (LC) by addressing cell-autonomous mechanisms using gain-of-function and loss-of-function approaches and protein expression profiling of tissue samples in our clinical biobank. PON1 expression in LC patient tissues varied between overexpression in squamous cell carcinoma and minimal loss in adenocarcinoma sub-types. Simultaneous overexpression of PON1 both at the gene and protein stability levels induced pro-oncogenic characteristics in LC cells and xenografts. PON1 overexpression supported metastatic progression of LC by decreasing G1/S ratio and LC cell senescence involving p21Waf1/Cip1. PON1 suppressed drug- and ligand-induced cell death and protected LC cells from genotoxic damages with maintained ATP levels, requiring p53-directed signals. PON1 promoted ROS deregulation protecting the mitochondria from dysregulation. PON1 knockdown resulted in the blockage of its antioxidant function in LC cells through Akt signaling with reduced invasive signature as a consequence of scant expression. Targeted glycolysis stimulated PON1 antioxidant activity regulating phosphorylation of AMPK-α. The functional data imply that exploitation of the antioxidative function of PON1 is consequential in driving LC pathogenesis at the cell-autonomous mechanistic level with consequences on tumor growth.