Afatinib Decreases P-Glycoprotein Expression to Promote Adriamycin Toxicity of A549T Cells

Non-coding RNA-based therapeutics in cancer therapy: An emphasis on Wnt/β-catenin control

Non-coding RNA transcripts are RNA molecules that have mainly regulatory functions and they do not encode proteins. microRNAs (miRNAs), lncRNAs and circRNAs are major types of this family and these epigenetic factors participate in disease pathogenesis, especially cancer that their abnormal expression may lead to cancer progression. miRNAs and lncRNAs possess a linear structure, whereas circRNAs possess ring structures and high stability. Wnt/β-catenin is an important factor in cancer with oncogenic function and it can increase growth, invasion and therapy resistance in tumors. Wnt upregulation occurs upon transfer of β-catenin to nucleus. Interaction of ncRNAs with Wnt/β-catenin signaling can determine tumorigenesis. Wnt upregulation is observed in cancers and miRNAs are able to bind to 3'-UTR of Wnt to reduce its level. LncRNAs can directly/indirectly regulate Wnt and in indirect manner, lncRNAs sponge miRNAs. CircRNAs are new emerging regulators of Wnt and by its stimulation, they increase tumor progression. CircRNA/miRNA axis can affect Wnt and carcinogenesis. Overall, interaction of ncRNAs with Wnt can determine proliferation rate, migration ability and therapy response of cancers. Furthermore, ncRNA/Wnt/β-catenin axis can be utilized as biomarker in cancer and for prognostic applications in patients.

Afatinib triggers a Ni2+ -resistant Ca2+ influx pathway in A549 non-small cell lung cancer cells

Afatinib is used to treat non-small cell lung cancer cells (NSCLC), and its mechanism involves irreversible inhibition of epidermal growth factor receptor (EGFR) tyrosine kinase. In this study, we examined if afatinib had cytotoxic action against NSCLC other than inhibition of tyrosine kinase. Afatinib (1-30 μM) caused apoptotic death in A549 NSCLC in a concentration-dependent manner. Afatinib triggered Ca²⁺ influx without causing Ca²⁺ release, and the Ca²⁺ influx was unaffected by sodium orthovanadate (SOV, an inhibitor of tyrosine phosphatase), suggesting that afatinib-triggered Ca²⁺ response was unrelated to its inhibition of tyrosine kinase. Addition of afatinib also promoted Mn²⁺ influx. Ca²⁺ influx triggered by afatinib was resistant to SKF96365 and ruthenium red (two general blockers of TRP channels) and, unexpectedly, Ni²⁺ (a non-specific Ca²⁺ channel blocker). Afatinib caused an increase in mitochondrial Ca²⁺ level, an initial mitochondrial hyperpolarization (4 h) and followed by mitochondrial potential collapse (24-48 h). Afatinib-induced cell death was slightly but significantly alleviated in low extracellular Ca²⁺ condition or under pharmacological block of mitochondrial permeability transition pore (MPTP) opening by cyclosporin A. Therefore, in addition to tyrosine kinase inhibition as a major anti-cancer mechanism of afatinib, stimulation of an atypical Ca²⁺ influx pathway, mitochondrial Ca²⁺ overload, and potential collapse in part contribute to afatinib-induced cell death.

ERBB and P-glycoprotein inhibitors break resistance in relapsed neuroblastoma models through P-glycoprotein

Chemotherapy resistance is a persistent clinical problem in relapsed high-risk neuroblastomas. We tested a panel of 15 drugs for sensitization of neuroblastoma cells to the conventional chemotherapeutic vincristine, identifying tariquidar, an inhibitor of the transmembrane pump P-glycoprotein (P-gp/ABCB1), and the ERBB family inhibitor afatinib as the top resistance breakers. Both compounds were efficient in sensitizing neuroblastoma cells to vincristine in trypan blue exclusion assays and in inducing apoptotic cell death. The evaluation of ERBB signaling revealed no functional inhibition, that is, dephosphorylation of the downstream pathways upon afatinib treatment but direct off-target interference with P-gp function. Depletion of ABCB1, but not ERRB4, sensitized cells to vincristine treatment. P-gp inhibition substantially broke vincristine resistance in vitro and in vivo (zebrafish embryo xenograft). The analysis of gene expression datasets of more than 50 different neuroblastoma cell lines (primary and relapsed) and more than 160 neuroblastoma patient samples from the pediatric precision medicine platform INFORM (Individualized Therapy For Relapsed Malignancies in Childhood) confirmed a pivotal role of P-gp specifically in neuroblastoma resistance at relapse, while the ERBB family appears to play a minor part.

Involvement of P-gp on Reversing Multidrug Resistance Effects of 23-Hydroxybetulinic Acid on Chemotherapeutic Agents

Betulinic acid (BA) and 23-Hydroxybetulinic acid (23-HBA) are natural products with similar structures, which show a range of biological effects including cytotoxicity activity. The aim of current research was to investigate and evaluate the combinational cytotoxicity of BA and 23-HBA with chemotherapeutic agents in vitro, and to clarify the potential interaction and related mechanism with P-gp. Instead of BA, 23-HBA could increase cytotoxicity of MCF-7/ADR cells to adriamaycin (ADR) and vincristine (VCR). The intracellular accumulation of ADR/VCR in MCF-7/ADR cells was obviously increased in the presence of 23-HBA. Furthermore, 23-HBA could show dose-dependent increase on the transport of VCR and digoxin, which are typical P-gp substrates, in both MDCK-MDR1 and Caco-2 cells. However, the transport of BA and 23-HBA was not influenced by P-gp inhibition in MDCK-MDR1 cells. MDR1 shift assay and molecular docking model suggested that both compounds showed interaction with P-gp, yet the binding affinity and sites are different. In conclusion, 23-HBA could strongly improve the efficacy of anti-tumor agents in multidrug resistance (MDR) cells, which was related to P-gp inhibition. The MDR1 shift assay and molecular docking study further revealed that 23-HBA and BA showed different interaction modes with P-gp.

Afatinib induces pro-survival autophagy and increases sensitivity to apoptosis in stem-like HNSCC cells

Afatinib, a second-generation tyrosine kinase inhibitor (TKI), exerts its antitumor effects in head and neck squamous cell carcinoma (HNSCC) by inducing intrinsic apoptosis through suppression of mTORC1. However, the detailed mechanism and biological significance of afatinib-induced autophagy in HNSCC remains unclear. In the present study, we demonstrated that afatinib induced mTORC1 suppression-mediated autophagy in HNSCC cells. Further mechanistic investigation revealed that afatinib stimulated REDD1-TSC1 signaling, giving rise to mTORC1 inactivation and subsequent autophagy. Moreover, ROS generation elicited by afatinib was responsible for the induction of the REDD1-TSC1-mTORC1 axis. In addition, pharmacological or genetic inhibition of autophagy sensitized HNSCC cells to afatinib-induced apoptosis, demonstrating that afatinib activated pro-survival autophagy in HNSCC cells. Importantly, in vitro and in vivo assays showed that afatinib caused enhanced apoptosis but weaker autophagy in stem-like HNSCC cells constructed by CDH1 knockdown. This suggested that blocking autophagy has the potential to serve as a promising strategy to target HNSCC stem cells. In conclusion, our findings suggested that the combination treatment with afatinib and autophagy inhibitors has the potential to eradicate HNSCC cells, especially cancer stem cells in clinical therapy.

PXR Modulates the Prostate Cancer Cell Response to Afatinib by Regulating the Expression of the Monocarboxylate Transporter SLC16A1

Simple Summary

Many kinase inhibitors have been tested as potential alternatives for the treatment of castration-resistant prostate cancers. However, none of these clinical trials led to drug approval despite interesting responses. Our study reveals that genes involved in drug metabolism and their master regulator PXR (Pregnane X Receptor) could be responsible, at least in part, for these disappointing results as they can modulate tumor cell response to specific kinase inhibitors. We found that stable expression of PXR sensitized prostate cancer cells to erlotinib, dabrafenib, and afatinib, while it rendered cells resistant to dasatinib and had no effect for other inhibitors tested. We also report for the first time that sensitization to afatinib is due to an alteration in drug transport that involves the SLC16A1 monocarboxylate transporter. Together, our results further indicate that PXR might be considered as a biomarker of response to kinase inhibitors in castration-resistant prostate cancers.

Abstract

Resistance to castration is a crucial issue in the treatment of metastatic prostate cancer. Kinase inhibitors (KIs) have been tested as potential alternatives, but none of them are approved yet. KIs are subject of extensive metabolism at both the hepatic and the tumor level. Here, we studied the role of PXR (Pregnane X Receptor), a master regulator of metabolism, in the resistance to KIs in a prostate cancer setting. We confirmed that PXR is expressed in prostate tumors and is more frequently detected in advanced forms of the disease. We showed that stable expression of PXR in 22Rv1 prostate cancer cells conferred a resistance to dasatinib and a higher sensitivity to erlotinib, dabrafenib, and afatinib. Higher sensitivity to afatinib was due to a ~ 2-fold increase in its intracellular accumulation and involved the SLC16A1 transporter as its pharmacological inhibition by BAY-8002 suppressed sensitization of 22Rv1 cells to afatinib and was accompanied with reduced intracellular concentration of the drug. We found that PXR could bind to the SLC16A1 promoter and induced its transcription in the presence of PXR agonists. Together, our results suggest that PXR could be a biomarker of response to kinase inhibitors in castration-resistant prostate cancers.

Repurposing Tyrosine Kinase Inhibitors to Overcome Multidrug Resistance in Cancer: A Focus on Transporters and Lysosomal Sequestration

Tyrosine kinase inhibitors (TKIs) are being increasingly used to treat various malignancies. Although they were designed to target aberrant tyrosine kinases, they are also intimately linked with the mechanisms of multidrug resistance (MDR) in cancer cells. MDR-related solute carrier (SLC) and ATB-binding cassette (ABC) transporters are responsible for TKI uptake and efflux, respectively. However, the role of TKIs appears to be dual because they can act as substrates and/or inhibitors of these transporters. In addition, several TKIs have been identified to be sequestered into lysosomes either due to their physiochemical properties or via ABC transporters expressed on the lysosomal membrane. Since the development of MDR represents a great concern in anticancer treatment, it is important to elucidate the interactions of TKIs with MDR-related transporters as well as to improve the properties that would prevent TKIs from diffusing into lysosomes. These findings not only help to avoid MDR, but also help to define the possible impact of combining TKIs with other anticancer drugs, leading to more efficient therapy and fewer adverse effects in patients.

Dual Inhibitors as a New Challenge for Cancer Multidrug Resistance Treatment

BACKGROUND

Dual-targeting in cancer treatment by a single drug is an unconventional approach in relation to drug combinations. The rationale for the development of dualtargeting agents is to overcome incomplete efficacy and drug resistance frequently present when applying individual targeting agents. Consequently, -a more favorable outcome of cancer treatment is expected with dual-targeting strategies.

METHODS

We reviewed the literature, concentrating on the association between clinically relevant and/or novel dual inhibitors with the potential to modulate multidrug resistant phenotype of cancer cells, particularly the activity of P-glycoprotein. A balanced analysis of content was performed to emphasize the most important findings and optimize the structure of this review.

RESULTS

Two-hundred and forty-five papers were included in the review. The introductory part was interpreted by 9 papers. Tyrosine kinase inhibitors' role in the inhibition of Pglycoprotein and chemosensitization was illustrated by 87 papers. The contribution of naturalbased compounds in overcoming multidrug resistance was reviewed using 92 papers, while specific dual inhibitors acting against microtubule assembling and/or topoisomerases were described with 55 papers. Eleven papers gave an insight into a novel and less explored approach with hybrid drugs. Their influence on P-glycoprotein and multidrug resistance was also evaluated.

CONCLUSION

These findings bring into focus rational anticancer strategies with dual-targeting agents. Most evaluated synthetic and natural drugs showed a great potential in chemosensitization. Further steps in this direction are needed for the optimization of anticancer treatment.

Improving the anticancer effect of afatinib and microRNA by using lipid polymeric nanoparticles conjugated with dual pH-responsive and targeting peptides

Background

The emergence of resistance to chemotherapy or target therapy, tumor metastasis, and systemic toxicity caused by available anticancer drugs hamper the successful colorectal cancer (CRC) treatment. The rise in epidermal growth factor receptor (EGFR; human epidermal growth factor receptor 1; HER1) expression and enhanced phosphorylation of HER2 and HER3 are associated with tumor resistance, metastasis and invasion, thus resulting in poor outcome of anti-CRC therapy. The use of afatinib, a pan-HER inhibitor, is a potential therapeutic approach for resistant CRC. Additionally, miR-139 has been reported to be negatively correlated with chemoresistance, metastasis, and epithelial–mesenchymal transition (EMT) of CRC. Hence, we develop a nanoparticle formulation consisting of a polymer core to carry afatinib or miR-139, which is surrounded by lipids modified with a targeting ligand and a pH-sensitive penetrating peptide to improve the anticancer effect of cargos against CRC cells.

Results

Our findings show that this formulation displays a spherical shape with core/shell structure, homogeneous particle size distribution and negative zeta potential. The prepared formulations demonstrate a pH-sensitive release profile and an enhanced uptake of cargos into human colorectal adenocarcinoma Caco-2 cells in response to the acidic pH. This nanoparticle formulation incorporating afatinib and miR-139 exhibits low toxicity to normal cells but shows a better inhibitory effect on Caco-2 cells than other formulations. Moreover, the encapsulation of afatinib and miR-139 in peptide-modified nanoparticles remarkably induces apoptosis and inhibits migration and resistance of Caco-2 cells via suppression of pan-HER tyrosine kinase/multidrug resistance/metastasis pathways.

Conclusion

This study proposes a multifunctional nanoparticle formulation for targeted modulation of apoptosis/EGFR/HER/EMT/resistance/progression pathways to increase the sensitivity of colon cancer cells to afatinib.

Electronic supplementary material

The online version of this article (10.1186/s12951-019-0519-6) contains supplementary material, which is available to authorized users.

Combination of dihydromyricetin and ondansetron strengthens antiproliferative efficiency of adriamycin in K562/ADR through downregulation of SORCIN: A new strategy of inhibiting P-glycoprotein

Though the advancement of chemotherapy drugs alleviates the progress of cancer, long-term therapy with anticancer agents gradually leads to acquired multidrug resistance (MDR), which limits the survival outcomes in patients. It was shown that dihydromyricetin (DMY) could partly reverse MDR by suppressing P-glycoprotein (P-gp) and soluble resistance-related calcium-binding protein (SORCIN) independently. To reverse MDR more effectively, a new strategy was raised, that is, circumventing MDR by the coadministration of DMY and ondansetron (OND), a common antiemetic drug, during cancer chemotherapy. Meanwhile, the interior relation between P-gp and SORCIN was also revealed. The combination of DMY and OND strongly enhanced antiproliferative efficiency of adriamycin (ADR) because of the increasing accumulation of ADR in K562/ADR-resistant cell line. DMY could downregulate the expression of SORCIN and P-gp via the ERK/Akt pathways, whereas OND could not. In addition, it was proved that SORCIN suppressed ERK and Akt to inhibit P-gp by the silence of SORCIN, however, not vice versa. Finally, the combination of DMY, OND, and ADR led to G2/M cell cycle arrest and apoptosis via resuming P53 function and restraining relevant proteins expression. These fundamental findings provided a promising approach for further treatment of MDR.