Gemcitabine-induced pancreatic cancer cell death is associated with MST1/cyclophilin D mitochondrial complexation

Synergistic Inhibition of Pancreatic Cancer Cell Growth and Migration by Gemcitabine and Withaferin A

Pancreatic cancer remains one of the most lethal malignancies due to its aggressive nature and resistance to conventional therapies. This study investigates the anti-proliferative, pro-apoptotic, and anti-migratory effects of Gemcitabine (GC) and Withaferin A (WFA) on pancreatic cancer cell lines PANC-1 and Hs766t. The MTS assay revealed that both compounds effectively inhibit cell proliferation, with WFA showing a stronger effect in Hs766t cells. Flow cytometry analysis demonstrated that GC and WFA, particularly in combination, significantly induce apoptosis in both cell lines. Migration assays confirmed the potent inhibition of cell migration by both compounds, with the combination treatment being the most effective. Furthermore, actin cytoskeleton analysis indicated substantial changes in cell morphology and stiffness, suggesting that GC and WFA disrupt the structural integrity of cancer cells. Additionally, the study highlights a ROS-mediated mechanism underlying the effects of GC and WFA, as evidenced by increased ROS levels following treatment, which were attenuated by N-acetylcysteine. Importantly, NF-κB activity was significantly modulated, with WFA reducing NF-κB activation induced by GC, potentially contributing to the synergistic pro-apoptotic effect of the combination. These findings suggest that the combination of GC and WFA may offer a synergistic therapeutic approach for treating pancreatic cancer by targeting multiple aspects of tumor cell behavior.

Combining gemcitabine and MSC delivering soluble TRAIL to target pancreatic adenocarcinoma and its stroma

Pancreatic ductal adenocarcinoma (PDAC) still has a poor response to therapies, partly due to their cancer-associated fibroblasts (CAFs). Here, we investigate the synergistic impact of a combinatory approach between a known chemotherapy agent, such as gemcitabine (GEM), and gene-modified human mesenchymal stromal/stem cells (MSCs) secreting the pro-apoptotic soluble (s)TRAIL (sTRAIL MSCs) on both PDAC cells and CAFs. The combo significantly impacts on PDAC survival in 2D and 3D models. In orthotopic xenograft models, GEM and sTRAIL MSCs induce tumor architecture shredding with a reduction of CK7- and CK8/18-positive cancer cells and the abrogation of spleen metastases. A cytotoxic effect on primary human CAFs is also observed along with an alteration of their transcriptome and a reduction of the related desmoplasia. Collectively, we demonstrate a promising therapeutic profile of combining GEM and sTRAIL MSCs to target both tumoral and stromal compartments in PDAC.

Cyclophilin D: Guardian or Executioner for Tumor Cells?

Cyclophilin D (CypD) is a peptide-proline cis-trans isomerase (PPIase) distributed in the mitochondrial matrix. CypD regulates the opening of the mitochondrial permeability conversion pore (mPTP) and mitochondrial bioenergetics through PPIase activity or interaction with multiple binding partners in mitochondria. CypD initially attracted attention due to its regulation of mPTP overopening-mediated cell death. However, recent studies on the effects of CypD on tumors have shown conflicting results. Although CypD has been proven to promote the aerobic glycolysis in tumor cells, its regulation of malignant characteristics such as the survival, invasion and drug resistance of tumor cells remains controversial. Here, we elaborate the main biological functions of CypD and its relationships with tumor progression identified in recent years, focusing on the dual role of CypD in tumors.

Anticancer Drugs-induced Capillary Leak Syndrome

The term capillary leak syndrome (CLS) describes the manifestations associated with an increased capillary permeability to proteins leading to an escape of plasma from the blood circulatory system to surrounding tissues, muscle, organs, or body cavities. This results clinically in the typical triad of hypotension, edema, and elevated hematocrit. The more severe cases of CLS may present with cardiovascular collapse, shock, and death. The most classic form of this pathology is represented by the idiopathic systemic CLS (SCLS) also called Clarkson’s disease, but capillary leaks are also described as adverse drug reactions foremost among which are anticancer drugs. This review will focus on oncologic drugs such as gemcitabine, therapeutic growth factors or cytokines, and monoclonal antibodies (mAbs) that appear now as the strongest candidates for anticancer drug-induced CLS.

Mst2 Overexpression Inhibits Thyroid Carcinoma Growth and Metastasis by Disrupting Mitochondrial Fitness and Endoplasmic Reticulum Homeostasis

Although the incidence of thyroid carcinoma has increased over the past several decades, it has an excellent prognosis and overall 5-year survival, with a stable mortality rate, except in cases with advanced stages or rare malignant tumor types. Biomarkers have emerged as effective targets of molecular therapy against thyroid carcinoma due to their rapid and convenient detection; however, there has been little clinical application. Macrophage stimulating 2 (Mst2) is a proapoptotic protein with implications in carcinogenesis and metastasis. We found that Mst2 overexpression-induced endoplasmic reticulum (ER) stress in MDA-T32 thyroid carcinoma cells, accompanied by elevated caspase-12 activity, increased apoptotic rate, and reduced cell viability. In addition, Mst2 overexpression contributed to mitochondrial damage, as evidenced by increased mitochondrial oxidative stress and activated the mitochondrial apoptotic pathway. Inhibition of the JNK pathway abolished these effects. These results show Mst2 to be a novel tumor suppressor that induces mitochondrial dysfunction and ER stress via the JNK pathway. Thus, Mst2 could potentially serve as a biomarker for developing targeted therapy against thyroid carcinoma.

The Role of Cyclophilins in Inflammatory Bowel Disease and Colorectal Cancer

Cyclophilins (Cyps) is a kind of ubiquitous protein family in organisms, which has biological functions such as promoting intracellular protein folding and participating in the pathological processes of inflammation and tumor. Inflammatory bowel disease (IBD) and colorectal cancer (CRC) are two common intestinal diseases, but the etiology and pathogenesis of these two diseases are still unclear. IBD and CRC are closely associated, IBD has always been considered as one of the main risks of CRC. However, the role of Cyps in these two related intestinal diseases is rarely studied and reported. In this review, the expression of CypA, CypB and CypD in IBD, especially ulcerative colitis (UC), and CRC, their relationship with the development of these two intestinal diseases, as well as the possible pathogenesis, were briefly summarized, so as to provide modest reference for clinical researches and treatments in future.

Chrysophanol localizes in mitochondria to promote cell death through upregulation of mitochondrial cyclophilin D in HepG2 cells

Objective

Chrysophanol (Chry) displays potent anticancer activity in human cancer cells and animal models, but the cellular targets of Chry have not been fully defined. Herein, we speculated whether mitochondria were a target involved in Chry-induced cytotoxicity.

Methods

Human liver cancer cell line HepG2 was incubated. The cytotoxicity was evaluated by MTT assay. Mitochondria localization was evaluated by a confocal microscopy. Mitochondrial membrane potential ΔΨm was detected by TMRE staining and determined by the flow cytometer. The levels of ATP, mitochondrial superoxide anions, and GSH/GSSG were determined according to the assay kits. The apoptosis were evaluated through Hoechst33342/PI and Annexin V/PI staining, respectively. The expression of cyclophilin D (CyPD) was determined by immunoblot method, and the interaction between CyPD and Chry was analyzed by molecule docking procedure.

Results

Chry itself mainly localized in mitochondria to cause mitochondrial dysfunction and cell death in HepG2 cells. As regard to the mechanism, cyclosporin A as the inhibitor for the formation of mitochondrial permeability transition pore (mPTP) moderately suppressed cell death, indicating mPTP involved in the process of cell death. Further, Chry enhanced the protein expression of Cyclophilin D (CyPD) which is a molecular componentry and a modulator of mPTP, while antioxidant N-acetyl-L-cysteine inhibited the expression of CyPD. Molecule docking procedure disclosed two hydrogen-bonds existed in CyPD-Chry complex with −11.94 kal/mol of the binding affinity value. Besides, the mtDNA-deficient HepG₂-ρ0 cells were much resistant to Chry-induced cell death, indicating mtDNA at least partly participated in cell death. A combination of Chry and VP-16 produced the synergism effect toward cell viability and ΔΨm, while Chry combined with Cis-Pt elicited the antagonism effect.

Conclusion

Taken together, enrichment in mitochondria and actions on mPTP, CyPD and mtDNA provides an insight into the anticancer mechanism of Chry. The combination therapy for Chry with clinical drugs may deserve to further explore.

The role of mitochondrial ATP synthase in cancer

The mitochondrial ATP synthase is a multi-subunit enzyme complex located in the inner mitochondrial membrane which is essential for oxidative phosphorylation under physiological conditions. In this review, we analyse the enzyme functions involved in cancer progression by dissecting specific conditions in which ATP synthase contributes to cancer development or metastasis. Moreover, we propose the role of ATP synthase in the formation of the permeability transition pore (PTP) as an additional mechanism which controls tumour cell death. We further describe transcriptional and translational modifications of the enzyme subunits and of the inhibitor protein IF1 that may promote adaptations leading to cancer metabolism. Finally, we outline ATP synthase gene mutations and epigenetic modifications associated with cancer development or drug resistance, with the aim of highlighting this enzyme complex as a potential novel target for future anti-cancer therapy.

Silver Nanotriangles and Chemotherapeutics Synergistically Induce Apoptosis in Glioma Cells via a ROS-Dependent Mitochondrial Pathway

Background

The synergistic effect of nanomaterials and chemotherapeutics provides a novel strategy for the treatment of tumors. Silver nanotriangles (AgNTs) exhibited some unique properties in nanomedicine. Studies on the synergy of silver-based nanomaterials and anti-tumor drugs against gliomas are rare.

Materials and Methods

Chitosan-coated AgNTs were prepared, followed by characterization using transmission electron microscopy, ultraviolet-visible spectroscopy and X-ray diffraction. The anti-glioma effect of cyclophosphamide (CTX), 5-fluorouracil (5-FU), oxaliplatin (OXA), doxorubicin (DOX) or gemcitabine (GEM) combined with AgNTs in different glioma cell lines (U87, U251 and C6) was assessed by the MTT assay to screen out a drug with the most broad-spectrum and strongest synergistic anti-glioma activity. The intracellular reactive oxygen species (ROS) level, mitochondrial membrane potential (MMP) and cell apoptosis were detected by flow cytometry. The possible underlying mechanisms of the synergy were further investigated with ROS scavenger and specific inhibitors of C-jun N-terminal kinase (JNK), p38 and extracellular signal-regulated kinase 1/2 pathways.

Results

The synthesized AgNTs were mainly triangular and truncated triangular with an average edge length of 125 nm. A synergistic anti-glioma effect of AgNTs combined with CTX was not observed, and the synergism between AgNTs and 5-FU was cell type-specific. AgNTs combined with OXA, DOX or GEM displayed synergistic effects in various glioma cell lines, and the combination of AgNTs and GEM showed the strongest synergistic activity. A decrease in cell viability, loss of the MMP and an increase in apoptosis rate induced by this synergy could be significantly attenuated by the ROS scavenger N-acetylcysteine and JNK inhibitor SP600125.

Conclusion

Our results suggested that the combination of AgNTs and GEM possessed broad-spectrum and potent synergistic anti-glioma activity, resulting from cell apoptosis mediated by a ROS-dependent mitochondrial pathway in which JNK might be involved.

The therapeutic value of the SphK1-targeting microRNA-3677 in human osteosarcoma cells

Sphingosine kinase 1 (SphK1) is a potential therapeutic target for human osteosarcoma (OS). SphK1-targeting microRNAs (miRNAs) could have important therapeutic value for OS. We discovered that micorRNA-3677 (miR-3677) is a SphK1-targeting miRNA, inhibiting OS cell progression. The results of RNA-Pull down assay confirmed direct binding between biotinylated-miR-3677 and SphK1 mRNA in primary human OS cells. In established and primary human OS cells forced overexpression of miR-3677, by a lentiviral construct, decreased SphK1 3’-UTR (untranslated region) activity and downregulated SphK1 expression. Both were however enhanced with miR-3677 inhibition in OS cells. Function studies demonstrated that OS cell growth, proliferation and migration were inhibited with miR-3677 overexpression, but augmented with miR-3677 inhibition. MiR-3677 overexpression-induced anti-OS cell activity was reversed with re-expression of the 3’-UTR-depleted SphK1. Additionally, in SphK1 knockout OS cells (by CRISPR/Cas9 strategy), altering miR-3677 expression failed to further alter cell functions. Finally, we show that miR-3677 expression was significantly downregulated in primary human OS tissues, correlating with SphK1 mRNA upregulation. We conclude that targeting SphK1 by miR-3677 inhibits human OS cell progression.

microRNA-1203 targets and silences cyclophilin D to protect human endometrial cells from oxygen and glucose deprivation-re-oxygenation

Oxygen and glucose deprivation (OGD)-re-oxygenation (OGDR) stimulation to the human endometrial cells mimics ischemia-reperfusion injury. Cyclophilin D (CypD)-dependent programmed necrosis pathway mediates OGDR-induced cytotoxicity to human endometrial cells. We here identified a novel CypD-targeting miRNA, microRNA-1203 (miR-1203). In T-HESC and primary human endometrial cells, ectopic overexpression of miR-1203, using a lentiviral construct, potently downregulated the CypD 3’-untranslated region (3’-UTR) activity and its expression. Both were however upregulated in endometrial cells with forced miR-1203 inhibition by its anti-sense sequence. Functional studies demonstrated that ectopic miR-1203 overexpression in endometrial cells alleviated OGDR-induced programmed necrosis, inhibiting mitochondrial CypD-p53-adenine nucleotide translocator 1 association, mitochondrial depolarization, reactive oxygen species production, and medium lactate dehydrogenase release. Contrarily OGDR-induced programmed necrosis and cytotoxicity were intensified with forced miR-1203 inhibition in endometrial cells. Significantly, ectopic miR-1203 overexpression or inhibition failed to change OGDR-induced cytotoxicity in CypD-knockout T-HESC cells. Furthermore, ectopic miR-1203 overexpression was unable to protect T-HESC endometrial cells from OGDR when CypD was restored by an UTR-depleted CypD construct. Collectively, these results show that miR-1203 targets and silences CypD to protect human endometrial cells from OGDR

Markers of pancreatic cancer stem cells and their clinical and therapeutic implications

Pancreatic cancer (PC) is the fourth most common cause of death among all cancers. Poor prognosis of PC may be caused by a prevalence of cancer stem cells (CSCs). CSCs are a population of cancer cells showing stem cell-like characteristics. CSCs have the ability to self-renew and may initiate tumorigenesis. PC CSCs express markers such as CD133, CD24, CD44, DCLK1, CXCR4, ESA, Oct4 and ABCB1. There is a wide complexity of interaction and relationships between CSC markers in PC. These markers are negative prognostic factors and are connected with tumor recurrence and clinical progression. Additionally, PC CSCs are resistant to treatment with gemcitabine. Thus, most current therapies for PC are ineffective. Numerous studies have shown, that targeting of these proteins may increase both disease-free and overall survival in PC.

Impact of ROS Generated by Chemical, Physical, and Plasma Techniques on Cancer Attenuation

For the last few decades, while significant improvements have been achieved in cancer therapy, this family of diseases is still considered one of the deadliest threats to human health. Thus, there is an urgent need to find novel strategies in order to tackle this vital medical issue. One of the most pivotal causes of cancer initiation is the presence of reactive oxygen species (ROS) inside the body. Interestingly, on the other hand, high doses of ROS possess the capability to damage malignant cells. Moreover, several important intracellular mechanisms occur during the production of ROS. For these reasons, inducing ROS inside the biological system by utilizing external physical or chemical methods is a promising approach to inhibit the growth of cancer cells. Beside conventional technologies, cold atmospheric plasmas are now receiving much attention as an emerging therapeutic tool for cancer treatment due to their unique biophysical behavior, including the ability to generate considerable amounts of ROS. This review summarizes the important mechanisms of ROS generated by chemical, physical, and plasma approaches. We also emphasize the biological effects and cancer inhibition capabilities of ROS.

DNA-SWCNT Biosensors Allow Real-Time Monitoring of Therapeutic Responses in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a highly desmoplastic cancer with limited treatment options. There is an urgent need for tools that monitor therapeutic responses in real time. Drugs such as gemcitabine and irinotecan elicit their therapeutic effect in cancer cells by producing hydrogen peroxide (H₂O₂). In this study, specific DNA-wrapped single-walled carbon nanotubes (SWCNT), which precisely monitor H₂O₂, were used to determine the therapeutic response of PDAC cells in vitro and tumors in vivo. Drug therapeutic efficacy was evaluated in vitro by monitoring H₂O₂ differences in situ using reversible alteration of Raman G-bands from the nanotubes. Implantation of the DNA-SWCNT probe inside the PDAC tumor resulted in approximately 50% reduction of Raman G-band intensity when treated with gemcitabine versus the pretreated tumor; the Raman G-band intensity reversed to its pretreatment level upon treatment withdrawal. In summary, using highly specific and sensitive DNA-SWCNT nanosensors, which can determine dynamic alteration of hydrogen peroxide in tumor, can evaluate the effectiveness of chemotherapeutics. SIGNIFICANCE: A novel biosensor is used to detect intratumoral hydrogen peroxide, allowing real-time monitoring of responses to chemotherapeutic drugs.

MST1 Suppresses Pancreatic Cancer Progression via ROS-Induced Pyroptosis

Pancreatic ductal adenocarcinoma (PDAC) is a deadly disease, and its incidence is increasing annually. It is critical to reveal and delineate the molecular mechanism promoting PDAC development and progression. Mammalian STE20-like kinase 1 (MST1) is a proapoptotic cytoplasmic kinase and also one of the core components of the Hippo pathway. Here, we showed that MST1 expression was decreased in PDAC, and restored expression of MST1 promoted PDAC cell death and suppressed the proliferation, migration, invasion, and cell spheroid formation of PDAC via caspase-1-induced pyroptosis. Further studies demonstrated that pyroptosis induced by MST1 was independent of the Hippo pathway, but mediated by reactive oxygen species (ROS). And ROS scavenger N-acetyl-cysteine attenuated the activation of caspase-1 induced by MST1 and the effect of MST1 in PDAC cell death, proliferation, migration, and invasion. Collectively, our study demonstrated that MST1 suppressed the progression of PDAC cells at least partly through ROS-induced pyroptosis. IMPLICATIONS: In this study, we identified a new mechanism of MST1 in inhibiting PDAC development and progression and revealed that MST1 would be a potential prognostic and therapeutic target for PDAC.

The footprints of mitochondrial impairment and cellular energy crisis in the pathogenesis of xenobiotics-induced nephrotoxicity, serum electrolytes imbalance, and Fanconi's syndrome: A comprehensive review

Fanconi's Syndrome (FS) is a disorder characterized by impaired renal proximal tubule function. FS is associated with a vast defect in the renal reabsorption of several chemicals. Inherited and/or acquired conditions seem to be connected with FS. Several xenobiotics including many pharmaceuticals are capable of inducing FS and nephrotoxicity. Although the pathological state of FS is well described, the exact underlying etiology and cellular mechanism(s) of xenobiotics-induced nephrotoxicity, serum electrolytes imbalance, and FS are not elucidated. Constant and high dependence of the renal reabsorption process to energy (ATP) makes mitochondrial dysfunction as a pivotal mechanism which could be involved in the pathogenesis of FS. The current review focuses on the footprints of mitochondrial impairment in the etiology of xenobiotics-induced FS. Moreover, the importance of mitochondria protecting agents and their preventive/therapeutic capability against FS is highlighted. The information collected in this review may provide significant clues to new therapeutic interventions aimed at minimizing xenobiotics-induced renal injury, serum electrolytes imbalance, and FS.

Enhancing responsiveness of pancreatic cancer cells to gemcitabine treatment under hypoxia by heme oxygenase-1 inhibition

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive malignancies and has one of the worst prognoses leading to a meager 5-year survival rate of ∼8%. Chemotherapy has had limited success in extending the life span of patients with advanced PDAC due to poor tumor perfusion and hypoxia-induced resistance. Hypoxia reprograms the gene expression profile and upregulates the expression of multiple genes including heme oxygenase-1 (HO-1), which provide survival advantage to PDAC cells. However, the relationships between HO-1, hypoxia, and response to chemotherapy is unclear. Our results showed that hypoxia upregulates the expression of HO-1 in PDAC cells, and HO-1 inhibition using the HO-1 inhibitors zinc protoporphyrin, tin protoporphyrin IX (SnPP), and HO-1 knockout using CRISPR/Cas9 suppresses the proliferation of PDAC cells under hypoxia and sensitize them to gemcitabine under in vitro conditions. Treating orthotopic tumors with SnPP, or SnPP in combination with gemcitabine, significantly reduced the weight of pancreatic tumors (P < 0.05), decreased metastasis and improved the efficacy of gemcitabine treatment (P < 0.05). Mechanistically, inhibition of HO-1 increased the production of reactive oxygen species as demonstrated by increased dihydroethidium, and Mitosox, disrupted glutathione cycle, and enhanced apoptosis. There was significant increase in cleaved caspase-3 staining in tumors after combined treatment with SnPP and gemcitabine comparing to control or gemcitabine alone. In addition, inhibiting HO-1 reduced expression of stemness markers (CD133, and CD44) as compared to control or gemcitabine. Overall, our study may present a novel therapeutic regimen that might be adopted for the treatment of PDAC patients.

Mst1-Hippo pathway triggers breast cancer apoptosis via inducing mitochondrial fragmentation in a manner dependent on JNK-Drp1 axis

BACKGROUND AND OBJECTIVE

Mst1-Hippo pathway and mitochondrial fragmentation participate in the progression of several types of cancers. However, their roles in breast cancer requires investigation. The aim of our study is to determine whether Mst1 overexpression regulates the viability of breast cancer cells via modulating mitochondrial fragmentation.

MATERIALS AND METHODS

TUNEL staining, MTT assay and Western blotting were used to detect cancer cell death. Adenovirus-loaded Mst1 was transfected into cells to overexpress Mst1. Mitochondrial fragmentation was observed via immunofluorescence staining and Western blotting. Pathway blocker was used to detect whether Mst1 modulated cell death and mitochondrial fragmentation via JNK signaling pathway.

RESULTS

Our data showed that Mst1 overexpression promoted breast cancer cell death in a manner dependent on mitochondrial apoptosis. Mitochondrial oxidative stress, energy metabolism disorder, mitochondrial cyt-c liberation and mitochondrial apoptosis activation were observed after Mst1 overexpression. Furthermore, we demonstrated that Mst1 overexpression activated mitochondrial stress via triggering Drp1-related mitochondrial fragmentation, and that inhibition of Drp1-related mitochondrial fragmentation abrogated the proapoptotic effect of Mst1 overexpression on breast cancer cells. To this end, we found that Mst1 modulated Drp1 expression via the JNK signaling pathway, and that blockade of the JNK pathway attenuated mitochondrial stress and repressed apoptosis in Mst1-overexpressed cells.

CONCLUSION

Altogether, our results identified a tumor suppressive role for Mst1 overexpression in breast cancer via activation of the JNK-Drp1 axis and subsequent initiation of fatal mitochondrial fragmentation. Given these findings, strategies to enhance Mst1 activity and elevate the JNK-Drp1-mitochondrial fragmentation cascade have clinical benefits for patients with breast cancer.

Poor expression of microRNA-135b results in the inhibition of cisplatin resistance and proliferation and induces the apoptosis of gastric cancer cells through MST1-mediated MAPK signaling pathway

Gastric cancer (GC) has been classified as the fourth leading cause of cancer-related deaths worldwide. Due to their ability to suppress the expression of target genes, microRNAs (miRNAs) are listed as one of the key elements involved in the formation and development of tumors. This study was therefore conducted to investigate the effects of microRNA-135b (miR-135b) on cisplatin [ cis-diamminedichloroplatinum (CDDP)] resistance of GC cells through the MAPK signaling pathway by targeting mammalian ste20-like kinase 1 (MST1). A microarray-based gene expression analysis was performed to screen the GC-related differentially expressed genes. The 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide assay was performed to determine the sensitivity of GC cells to CDDP. The bioinformatics database and dual luciferase reporter gene assay were used to check whether MST1 was a direct target gene of miR-135b. GC cell lines were prepared with high CDDP resistance, after which they were cultured and transfected respectively, followed by the administration of transfected cells into nude mice and subsequent treatment with CDDP in an attempt to identify the underlying mechanisms and functions of miR-135b in relation to MST1 in GC progression. The results were highly indicative of the crucial role played by MST1 in the development of GC and the sensitivity of GC to CDDP. miR-135b was found to regulate MST1, which in turn had an impact on the development of GC. MKN28 was observed to be most sensitive to CDDP, whereas MKN45 presented with the poorest sensitivity to CDDP. Furthermore, the down-regulation of miR-135b resulted in inactivation of the MAPK signaling pathway; increased the expression of MST1 and Bax; and decreased expression of p-p38MAPK, p-ERK1/2, P-glycoprotein, p38MAPK, ERK1/2, multidrug resistance protein 1, multidrug resistance-associated protein 1, lung resistance-related protein, and Bcl-2, thus inhibiting CDDP resistance of GC cells. The down-regulation of miR-135b also restrained cell proliferation and induced the apoptosis rate of GC cells. In summary, the results of this study showed that the down-regulation of miR-135b induced apoptosis, and it inhibited proliferation and CDDP resistance of GC cells by inactivating the MAPK signaling pathway and increasing the expression of MST1.-Zhou, J., Chen, Q. Poor expression of microRNA-135b results in the inhibition of cisplatin resistance and proliferation and induces the apoptosis of gastric cancer cells through MST1-mediated MAPK signaling pathway.

Cyclophilin D, Somehow a Master Regulator of Mitochondrial Function

Cyclophilin D (CyPD) is an important mitochondrial chaperone protein whose mechanism of action remains a mystery. It is well known for regulating mitochondrial function and coupling of the electron transport chain and ATP synthesis by controlling the mitochondrial permeability transition pore (PTP), but more recent evidence suggests that it may regulate electron transport chain activity. Given its identification as a peptidyl-prolyl, cis-trans isomerase (PPIase), CyPD, is thought to be involved in mitochondrial protein folding, but very few reports demonstrate the presence of this activity. By contrast, CyPD may also perform a scaffolding function, as it binds to a number of important proteins in the mitochondrial matrix and inner mitochondrial membrane. From a clinical perspective, inhibiting CyPD to inhibit PTP opening protects against ischemia⁻reperfusion injury, making modulation of CyPD activity a potentially important therapeutic goal, but the lack of knowledge about the mechanisms of CyPD's actions remains problematic for such therapies. Thus, the important yet enigmatic nature of CyPD somehow makes it a master regulator, yet a troublemaker, for mitochondrial function.

Targeting Oxidatively Induced DNA Damage Response in Cancer: Opportunities for Novel Cancer Therapies

Cancer is a death cause in economically developed countries that results growing also in developing countries. Improved outcome through targeted interventions faces the scarce selectivity of the therapies and the development of resistance to them that compromise the therapeutic effects. Genomic instability is a typical cancer hallmark due to DNA damage by genetic mutations, reactive oxygen and nitrogen species, ionizing radiation, and chemotherapeutic agents. DNA lesions can induce and/or support various diseases, including cancer. The DNA damage response (DDR) is a crucial signaling-transduction network that promotes cell cycle arrest or cell death to repair DNA lesions. DDR dysregulation favors tumor growth as downregulated or defective DDR generates genomic instability, while upregulated DDR may confer treatment resistance. Redox homeostasis deeply and capillary affects DDR as ROS activate/inhibit proteins and enzymes integral to DDR both in healthy and cancer cells, although by different routes. DDR regulation through modulating ROS homeostasis is under investigation as anticancer opportunity, also in combination with other treatments since ROS affect DDR differently in the patients during cancer development and treatment. Here, we highlight ROS-sensitive proteins whose regulation in oxidatively induced DDR might allow for selective strategies against cancer that are better tailored to the patients.

Ginseng Rh2 protects endometrial cells from oxygen glucose deprivation/re-oxygenation

In this study, oxygen glucose deprivation/re-oxygenation (OGDR) was applied to cultured endometrial cells to mimic ischemic-reperfusion injuries. We also tested the potential effect of Ginseng Rh2 (GRh2) against the process. In established T-HESC human endometrial cells and primary murine endometrial cells, GRh2 largely inhibited OGDR-induced viability reduction and cell death. Remarkably, OGDR induced programmed necrosis in the endometrial cells, evidenced by cyclophilin D-p53-adenine nucleotide translocator 1 (ANT-1) mitochondrial association, mitochondrial depolarization, reactive oxygen species production, and lactate dehydrogenase release. Notably, such effects by OGDR were largely attenuated with co-treatment of GRh2. Further, cyclophilin D inhibition or knockdown also protected endometrial cells from OGDR. On the other hand, forced over-expression of cyclophilin D facilitated OGDR-induced T-HESC cell necrosis, which was dramatically inhibited by GRh2. Together, GRh2 protects endometrial cells from OGDR possibly via inhibiting CypD-dependent programmed necrosis pathway.

HINT2 triggers mitochondrial Ca2+ influx by regulating the mitochondrial Ca2+ uniporter (MCU) complex and enhances gemcitabine apoptotic effect in pancreatic cancer

In early studies, it was shown that HINT2, which sensitizes cells to mitochondrial apoptosis, is down-regulated in hepatocellular carcinoma (HCC) cells (Martin et al., 2006). However, the molecular mechanism of this effect is unknown. Immunohistochemistry revealed that HINT2 expression is relatively low in pancreatic cancer tissues, compared to that in adjacent tissues (P < 0.05). Furthermore, its expression was related to pathological grade and lymph node metastasis (P = 0.0161 and 0.0108, respectively); in addition, down-regulation of HINT2 was found to be associated with relatively poor prognosis in pancreatic cancer patients. Up-regulation of HINT2 was shown to trigger pancreatic cancer cell apoptosis, decrease mitochondrial membrane potential (ΔΨm), promote intracellular reactive oxygen species (ROS) production, and elevate mitochondrial Ca²⁺ levels. However, co-treatment of HINT2 overexpressing BxPC-3 cells with ruthenium red partially inhibited HINT2-induced apoptosis, which was associated with a reduction in ΔΨm and an increase in intracellular ROS and mitochondrial Ca²⁺. According to our results, mitochondrial calcium uptake1 and 2 (MICU1 and MICU2) were down-regulated and the essential MCU regulator (EMRE) was up-regulated in cells transduced with Adv-HINT2. Therefore, we deduced that HINT2 triggers apoptosis in pancreatic cancer cells by regulating mitochondrial Ca²⁺ influx through the mitochondrial calcium uniporter (MCU). In addition, we found that HINT2 can sensitize BxPC-3 and L3.6pl cells to gemcitabine-induced apoptosis and that gemcitabine up-regulates HINT2 expression. This indicates that gemcitabine-induced apoptosis is related to HINT2 levels.

Mitochondrial permeability transition in cardiac ischemia-reperfusion: whether cyclophilin D is a viable target for cardioprotection?

Growing number of studies provide strong evidence that the mitochondrial permeability transition pore (PTP), a non-selective channel in the inner mitochondrial membrane, is involved in the pathogenesis of cardiac ischemia-reperfusion and can be targeted to attenuate reperfusion-induced damage to the myocardium. The molecular identity of the PTP remains unknown and cyclophilin D is the only protein commonly accepted as a major regulator of the PTP opening. Therefore, cyclophilin D is an attractive target for pharmacological or genetic therapies to reduce ischemia-reperfusion injury in various animal models and humans. Most animal studies demonstrated cardioprotective effects of PTP inhibition; however, a recent large clinical trial conducted by international groups demonstrated that cyclosporine A, a cyclophilin D inhibitor, failed to protect the heart in patients with myocardial infarction. These studies, among others, raise the question of whether cyclophilin D, which plays an important physiological role in the regulation of cell metabolism and mitochondrial bioenergetics, is a viable target for cardioprotection. This review discusses previous studies to provide comprehensive information on the physiological role of cyclophilin D as well as PTP opening in the cell that can be taken into consideration for the development of new PTP inhibitors.

The mitochondrion interfering compound NPC-26 exerts potent anti-pancreatic cancer cell activity in vitro and in vivo

The development of novel anti-pancreatic cancer agents is extremely important. Here, we investigated the anti-pancreatic cancer activity by NPC-26, a novel mitochondrion interfering compound. We showed that NPC-26 was anti-proliferative and cytotoxic to human pancreatic cancer cells, possibly via inducing caspase-9-dependent cell apoptosis. Pharmacological inhibition or shRNA-mediated silence of caspase-9 attenuated NPC-26-induced pancreatic cancer cell death and apoptosis. Further, NPC-26 treatment led to mitochondrial permeability transition pore (mPTP) opening in the cancer cells, which was evidenced by mitochondrial depolarization, ANT-1(adenine nucleotide translocator-1)-Cyp-D (cyclophilin-D) association and oxidative phosphorylation disturbance. mPTP blockers (cyclosporin and sanglifehrin A) or shRNA-mediated knockdown of key mPTP components (Cyp-D and ANT-1) dramatically attenuated NPC-26-induced pancreatic cancer cell apoptosis. Importantly, we showed that NPC-26, at a low concentration, potentiated gemcitabine-induced mPTP opening and subsequent pancreatic cancer cell apoptosis. In vivo, NPC-26 intraperitoneal injection significantly suppressed the growth of PANC-1 xenograft tumors in nude mice. Meanwhile, NPC-26 sensitized gemcitabine-mediated anti-pancreatic cancer activity in vivo. In summary, the results of this study suggest that NPC-26, alone or together with gemcitabine, potently inhibits pancreatic cancer cells possibly via disrupting mitochondrion.

The mitochondrial permeability transition pore in AD 2016: An update

Over the past 30years the mitochondrial permeability transition - the permeabilization of the inner mitochondrial membrane due to the opening of a wide pore - has progressed from being considered a curious artifact induced in isolated mitochondria by Ca(2+) and phosphate to a key cell-death-inducing process in several major pathologies. Its relevance is by now universally acknowledged and a pharmacology targeting the phenomenon is being developed. The molecular nature of the pore remains to this day uncertain, but progress has recently been made with the identification of the FOF1 ATP synthase as the probable proteic substrate. Researchers sharing this conviction are however divided into two camps: these believing that only the ATP synthase dimers or oligomers can form the pore, presumably in the contact region between monomers, and those who consider that the ring-forming c subunits in the FO sector actually constitute the walls of the pore. The latest development is the emergence of a new candidate: Spastic Paraplegia 7 (SPG7), a mitochondrial AAA-type membrane protease which forms a 6-stave barrel. This review summarizes recent developments of research on the pathophysiological relevance and on the molecular nature of the mitochondrial permeability transition pore. This article is part of a Special Issue entitled: Mitochondrial Channels edited by Pierre Sonveaux, Pierre Maechler and Jean-Claude Martinou.

In vitro Study of the Antagonistic Effect of Low-dose Liquiritigenin on Gemcitabine-induced Capillary Leak Syndrome in Pancreatic Adenocarcinoma via Inhibiting ROS- Mediated Signalling Pathways

BACKGROUND

To investigate in-vitro antagonistic effect of low-dose liquiritigenin on gemcitabine-induced capillary leak syndrome (CLS) in pancreatic adenocarcinoma via inhibiting reactive oxygen species (ROS)- mediated signalling pathways.

MATERIALS AND METHODS

Human pancreatic adenocarcinoma Panc-1 cells and human umbilical vein endothelial cells (HUVECs) were pre-treated using low-dose liquiritigenin for 24 h, then added into gemcitabine and incubated for 48 h. Cell viability, apoptosis rate and ROS levels of Panc-1 cells and HUVECs were respectively detected through methylthiazolyldiphenyl-tetrazoliumbromide (MTT) and flow cytometry. For HUVECs, transendothelial electrical resistance (TEER) and transcellular and paracellular leak were measured using transwell assays, then poly (ADP-ribose) polymerase 1 (PARP-1) and metal matrix proteinase-9 (MMP9) activity were assayed via kits, mRNA expressions of p53 and Rac-1 were determined through quantitative polymerase chain reaction (qPCR); The expressions of intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and PARP-1 were measured via western blotting.

RESULTS

Low-dose liquiritigenin exerted no effect on gemcitabine-induced changes of cell viability, apoptosis rate and ROS levels in Panc-1 cells, but for HUVECs, liquiritigenin (3 μM) could remarkably elevate gemcitabine- induced decrease of cell viability, transepithelial electrical resistance (TEER), pro-MMP9 level and expression of ICAM-1 and VCAM-1 (p<0.01). Meanwhile, it could also significantly decrease gemcitabine-induced increase of transcellular and paracellular leak, ROS level, PARP-1 activity, Act-MMP9 level, mRNA expressions of p53 and Rac-1, expression of PARP-1 and apoptosis rate (p<0.01).

CONCLUSIONS

Low-dose liquiritigenin exerts an antagonistic effect on gemcitabine-induced leak across HUVECs via inhibiting ROS-mediated signalling pathways, but without affecting gemcitabine-induced Panc-1 cell apoptosis. Therefore, low-dose liquiritigenin might be beneficial to prevent the occurrence of gemcitabine-induced CLS in pancreatic adenocarcinoma.

JNK suppression of chemotherapeutic agents-induced ROS confers chemoresistance on pancreatic cancer stem cells

Chemoresistance associated with cancer stem cells (CSCs), which is now being held responsible for the pervasive therapy resistance of pancreatic cancer, poses a major challenge to the successful management of this devastating malignancy. However, the molecular mechanism underlying the marked chemoresistance of pancreatic CSCs remains largely unknown. Here we show that JNK, which is upregulated in pancreatic CSCs and contributes to their maintenance, is critically involved in the resistance of pancreatic CSCs to 5-fluorouracil (5-FU) and gemcitabine (GEM). We found that JNK inhibition effectively sensitizes otherwise chemoresistant pancreatic CSCs to 5-FU and GEM. Significantly, JNK inhibition promoted 5-FU- and GEM-induced increase in intracellular reactive oxygen species (ROS), and scavenging intracellular ROS by use of N-acetylcysteine impaired JNK inhibition-mediated promotion of the cytotoxicity of 5-FU and GEM. Our findings thus suggest that JNK may contribute to the chemoresistance of pancreatic CSCs through prevention of chemotherapeutic agents-induced increase in intracellular ROS. Our findings also suggest that JNK inhibition combined with 5-FU- and/or GEM-based regimens may be a rational therapeutic approach to effectively eliminate pancreatic CSCs.

Reactive Oxygen Species and Targeted Therapy for Pancreatic Cancer

Pancreatic cancer is the fourth leading cause of cancer-related death in the United States. Reactive oxygen species (ROS) are generally increased in pancreatic cancer cells compared with normal cells. ROS plays a vital role in various cellular biological activities including proliferation, growth, apoptosis, and invasion. Besides, ROS participates in tumor microenvironment orchestration. The role of ROS is a doubled-edged sword in pancreatic cancer. The dual roles of ROS depend on the concentration. ROS facilitates carcinogenesis and cancer progression with mild-to-moderate elevated levels, while excessive ROS damages cancer cells dramatically and leads to cell death. Based on the recent knowledge, either promoting ROS generation to increase the concentration of ROS with extremely high levels or enhancing ROS scavenging ability to decrease ROS levels may benefit the treatment of pancreatic cancer. However, when faced with oxidative stress, the antioxidant programs of cancer cells have been activated to help cancer cells to survive in the adverse condition. Furthermore, ROS signaling and antioxidant programs play the vital roles in the progression of pancreatic cancer and in the response to cancer treatment. Eventually, it may be the novel target for various strategies and drugs to modulate ROS levels in pancreatic cancer therapy.

Icaritin activates JNK-dependent mPTP necrosis pathway in colorectal cancer cells

The colorectal cancer (CRC) is one leading contributor of cancer-related mortality worldwide. The search for effective anti-CRC agents is valuable. In the current study, we showed that icaritin (ICT), an active natural ingredient from the Chinese plant Epimedium, potently inhibited proliferation and survival of established (HT-29, HCT-116, DLD-1, and SW-620) and primary (patient-derived) CRC cells. Significantly, ICT mainly induced necrosis, but not apoptosis, in CRC cells. The necrosis inhibitor necrostatin-1 attenuated ICT-mediated cytotoxicity in CRC cells. We showed that ICT treatment in CRC cells induced mitochondrial permeability transition pore (mPTP) opening, which was evidenced by mitochondrial membrane potential (MMP) decrease and mitochondrial adenine nucleotide translocator-1 (ANT-1)-cyclophilin-D (CyPD) association. On the other hand, mPTP blockers, including sanglifehrin A, cyclosporin A, and bongkrekic acid, as well as siRNA-mediated knockdown of mPTP component (CyPD or ANT-1), significantly alleviated ICT-mediated cytotoxicity against CRC cells. We suggested that Jun-N-terminal kinase (JNK) activation by ICT mediated mPTP opening and subsequent CRC cell necrosis. JNK pharmacological inhibition, dominant negative mutation, or shRNA downregulation suppressed ICT-induced MMP reduction and subsequent HT-29 cell necrosis. In vivo, oral gavage of ICT dramatically inhibited HT-29 xenograft growth in nude mice. The in vivo activity by ICT was largely attenuated by co-administration with the mPTP blocker CsA. Collectively, our results showed that ICT exerts potent inhibitory effect against CRC cells in vitro and in vivo. JNK-dependent mPTP necrosis pathway could be key mechanism responsible for ICT's actions.

C6 ceramide dramatically increases vincristine sensitivity both in vivo and in vitro, involving AMP-activated protein kinase-p53 signaling

Use of the conventional cancer chemotherapy (i.e. vincristine) is limited in tumor cells exhibiting pre-existing or acquired resistance. Here, we found that C6 ceramide (C6) dramatically sensitized vincristine's activity. In vitro, C6 and vincristine coadministration induced substantial necrosis and apoptosis in multiple human cancer cell lines, which were accompanied by a profound AMP-activated protein kinase (AMPK) activation, subsequent p53 activation, mTORC1 inactivation and Bcl-2/HIF-1α downregulation. Such synergistic effects were attenuated by AMPK inactivation through genetic mutation or short hairpin RNA silencing. Coadministration-activated p53 translocated to mitochondria, and formed a complex with cyclophilin-D, leading to mitochondrial permeability transition pore opening and cell necrosis. Disrupting p53-Cyp-D complexation through pharmacological or genetic means reduced costimulation-induced cytotoxicity. In vivo, a liposomal C6 was synthesized, which dramatically enhanced the antiproliferative activity of vincristine on HCT-116 or A2780 xenografts. Together, C6 sensitizes vincristine-induced anticancer activity in vivo and in vitro, involving activating AMPK-p53 signaling.

Significance of expression of MST1 in homocysteine-induced hepatocyte apoptosis

AIM: To study the role of the mammalian sterile 20-like kinase 1 (MST1) gene in homocysteine-induced hepatocyte apoptosis.

METHODS: Five-week-old C57BL/6J mice of SPF grade were divided into four groups: a normal control group, an ApoE^-/- group, a high methionine diet group, and an intervention group (n = 12 each). In the normal control group, normal mice were fed a normal diet. In the ApoE^-/- group, male ApoE^-/- mice were fed a normal diet. In the high methionine diet group, male ApoE^-/- mice were fed a high methionine diet. In the intervention group, male ApoE^-/- mice were fed a high methionine diet plus folic acid and vitamin B₁₂. Transmission electron microscopy and DAPI staining were used to determine the level of apoptosis in hepatic tissue. qRT-PCR and Western blot were used to determine the expression of MST1. Hepatocytes were then cultured in the presence or absence of homocysteine (100 μmol/L) alone or 100 μmol/L homocysteine plus folic acid and vitamin B₁₂; flow cytometry was used to determine the level of hepatocytes apoptosis, and the expression of MST1 was detected by qRT-PCR and Western blot.

RESULTS: After the mice were fed for 14 wk, serum homocysteine level in the high methionine diet group was 2.3 and 1.9 times as high as that in the normal control group and the ApoE^-/- group (P < 0.01), respectively. Serum homocysteine level in the intervention group was 28% lower than that in the high methionine diet group (P < 0.01). These findings suggest that the model was successfully established. Electron microscopy showed that in the high methionine diet group, there were chromosome swelling or condensation, mitochondrial swelling, marked endoplasmic reticulum swelling and break, which suggested the trend of cell apoptosis in hepatic tissue. Compared with the normal control group and ApoE^-/- group, hepatic apoptosis level in the high methionine diet group was higher. However, hepatic apoptosis level in the intervention group was lower than that in the high methionine diet group. Compared with the normal control group and ApoE^-/- group, the expression of MST1 mRNA and protein in heapatic tissue in the high methionine diet group was upregulated (P < 0.05 or P < 0.01); however, MST1 expression in the intervention group was significantly lower than that in the high methionine diet group (P < 0.05). In vitro, compared with the normal control group, hepatocytes apoptosis level in the homocysteine alone group was significantly higher (P < 0.01); however, hepatocytes apoptosis level in the intervention group was significantly lower than that in the homocysteine alone group (P < 0.05). Compared with the normal control group, the expression of MST1 mRNA and protein in the homocysteine alone group was upregulated (P < 0.01); however, MST1 expression in the intervention group was significantly lower than that in the homocysteine alone group (P < 0.05).

CONCLUSION: MST1 expression is upregulated in homocysteine-induced hepatocyte apoptosis, and folic acid and vitamin B₁₂ can suppress the up-regulation of MST1.

ROS-p53-cyclophilin-D signaling mediates salinomycin-induced glioma cell necrosis

BACKGROUND

The primary glioblastoma multiforme (GBM) is the most malignant form of astrocytic tumor with an average survival of approximately 12-14 months. The search for novel and more efficient chemo-agents against this disease is urgent. Salinomycin induces broad anti-cancer effects; however, its role in GBM and the underlying mechanism are not clear.

RESULTS

Here we found that salinomycin induced both apoptosis and necrosis in cultured glioma cells, and necrosis played a major role in contributing salinomycin's cytotoxicity. Salinomycin induced p53 translocation to mitochondria, where it formed a complex with cyclophilin-D (CyPD). This complexation was required for mitochondrial permeability transition pore (mPTP) opening and subsequent programmed necrosis. Blockade of Cyp-D by siRNA-mediated depletion or pharmacological inhibitors (cyclosporin A and sanglifehrin A) significantly suppressed salinomycin-induced glioma cell necrosis. Meanwhile, p53 stable knockdown alleviated salinomycin-induced necrosis in glioma cells. Reactive oxygen species (ROS) production was required for salinomycin-induced p53 mitochondrial translocation, mPTP opening and necrosis, and anti-oxidants n-acetylcysteine (NAC) and pyrrolidine dithiocarbamate (PDTC) inhibited p53 translocation, mPTP opening and glioma cell death.

CONCLUSIONS

Thus, salinomycin mainly induces programmed necrosis in cultured glioma cells.

Cyclophilin D and myocardial ischemia-reperfusion injury: a fresh perspective

Reperfusion is characterized by a deregulation of ion homeostasis and generation of reactive oxygen species that enhance the ischemia-related tissue damage culminating in cell death. The mitochondrial permeability transition pore (mPTP) has been established as an important mediator of ischemia-reperfusion (IR)-induced necrotic cell death. Although a handful of proteins have been proposed to contribute in mPTP induction, cyclophilin D (CypD) remains its only bona fide regulatory component. In this review we summarize existing knowledge on the involvement of CypD in mPTP formation in general and its relevance to cardiac IR injury in specific. Moreover, we provide insights of recent advancements on additional functions of CypD depending on its interaction partners and post-translational modifications. Finally we emphasize the therapeutic strategies targeting CypD in myocardial IR injury. This article is part of a Special Issue entitled "Mitochondria: From Basic Mitochondrial Biology to Cardiovascular Disease".

Squamosamide derivative FLZ protects retinal pigment epithelium cells from oxidative stress through activation of epidermal growth factor receptor (EGFR)-AKT signaling

Reactive oxygen species (ROS)-mediated retinal pigment epithelium (RPE) cell apoptosis is attributed to age-related macular degeneration (AMD) pathogenesis. FLZ, a novel synthetic squamosamide derivative from a Chinese herb, Annona glabra, has displayed significant cyto-protective activity. In the current study, we explored the pro-survival effect of FLZ in oxidative stressed-RPE cells and studied the underlying signaling mechanisms. Our results showed that FLZ attenuated hydrogen peroxide (H2O2)-induced viability decrease and apoptosis in the RPE cell line (ARPE-19 cells) and in primary mouse RPE cells. Western blotting results showed that FLZ activated AKT signaling in RPE cells. The AKT-specific inhibitor, MK-2206, the phosphoinositide 3-kinase (PI3K)/AKT pan inhibitor, wortmannin, and AKT1-shRNA (short hairpin RNA) depletion almost abolished FLZ-mediated pro-survival/anti-apoptosis activity. We discovered that epidermal growth factor receptor (EGFR) trans-activation mediated FLZ-induced AKT activation and the pro-survival effect in RPE cells, and the anti-apoptosis effect of FLZ against H2O2 was inhibited by the EGFR inhibitor, PD153035, or by EGFR shRNA-knockdown. In conclusion, FLZ protects RPE cells from oxidative stress through activation of EGFR-AKT signaling, and our results suggest that FLZ might have therapeutic values for AMD.