Antitumor effects of a novel photosensitizer-mediated photodynamic therapy and its influence on the cell transcriptome

Photodynamic therapy(PDT)is a promising cancer treatment.This study investigated the antitumor effects and mechanisms of a novel photosensitizer meso-5-[ρ-diethylene triamine pentaacetic acid-aminophenyl]−10,15,20-triphenyl-porphyrin(DTP)mediated PDT(DTP-PDT).Cell viability,reactive oxygen species(ROS),and apoptosis were measured with a Cell Counting Kit-8 assay,DCFH-DA fluorescent probe,and Hoechst staining,respectively.Cell apoptosis-and autophagy-related proteins were examined using western blotting.RNA sequencing was used to screen differentially expressed mRNAs(DERs),and bioinformatic analysis was performed to identify the major biological events after DTP-PDT.Our results show that DTP-PDT inhibited cell growth and induced ROS generation in MCF-7 and SGC7901 cells.The ROS scavenger N-acetyl-L-cysteine(NAC)and the P38 MAPK inhibitor SB203580 alleviated DTP-PDT-induced cytotoxicity.DTP-PDT induced cell apoptosis together with upregulated Bax and downregulated Bcl-2,which could also be inhibited by NAC or SB203580.The level of LC3B-Ⅱ,a marker of autophagy,was increased by DTP-PDT.A total of 3496 DERs were obtained after DTP-PDT.Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses indicated that DERs included those involved in cytosolic ribosomes,the nuclear lumen,protein binding,cell cycle,protein targeting to the endoplasmic reticulum,and ribosomal DNA replication.Disease Ontology and Reactome enrichment analyses indicated that DERs were associated with a variety of cancers and cell cycle checkpoints.Protein-protein interaction results demonstrated that cdk1 and rps27a ranked in the top 10 interacting genes.Therefore,DTP-PDT could inhibit cell growth and induce cell apoptosis and autophagy,partly through ROS and the P38 MAPK signaling pathway.Genes associated with the cell cycle,ribosomes,DNA replication,and protein binding may be the key changes in DTP-PDT-mediated cytotoxicity.

Codelivery of anti-CD47 antibody and chlorin e6 using a dual pH-sensitive nanodrug for photodynamic immunotherapy of osteosarcoma

Osteosarcoma is a malignant tumor originating from bone tissue that progresses rapidly and has a poor patient prognosis.Immunotherapy has shown great potential in the treatment of osteosarcoma.However,the immunosuppressive microenvironment severely limits the efficacy of osteosarcoma treatment.The dual pH-sensitive nanocarrier has emerged as an effective antitumor drug delivery system that can selectively release drugs into the acidic tumor microenvironment.Here,we prepared a dual pH-sensitive nanocarrier,loaded with the photosensitizer Chlorin e6(Ce6)and CD47 monoclonal antibodies(aCD47),to deliver synergistic photodynamic and immunotherapy of osteosarcoma.On laser irradiation,Ce6 can generate reactive oxygen species(ROS)to kill cancer cells directly and induces immunogenic tumor cell death(ICD),which further facilitates the dendritic cell maturation induced by blockade of CD47 by aCD47.Moreover,both calreticulin released during ICD and CD47 blockade can accelerate phagocytosis of tumor cells by macrophages,promote antigen presentation,and eventually induce T lymphocyte-mediated antitumor immunity.Overall,the dual pH-sensitive nanodrug loaded with Ce6 and aCD47 showed excellent immune-activating and anti-tumor effects in osteosarcoma,which may lay the theoretical foundation for a novel combination model of osteosarcoma treatment.

Enhancing the Photosensitivity of Hypocrellin A by Perylene Diimide Metallacage‑Based Host–Guest Complexation for Photodynamic Therapy

The development of supramolecular hosts which can efficiently encapsulate photosensitizers to improve the photodynamic efficacy holds great promise for cancer therapy.Here,we report two perylene diimide-based metallacages that can form stable host–guest complexes with planar conjugated molecules including polycyclic aromatic hydrocarbons and photosensitizers(hypocrellin A).Such host–guest complexation not only prevents the aggregation of photosensitizers in aqueous environments,but also offers fluorescence resonance energy transfer(FRET)from the metallacage to the photosensitizers to further improve the singlet oxygen generation(Φ_(Δ)=0.66).The complexes are further assembled with amphiphilic polymers,forming nanoparticles with improved stability for anticancer study.Both in vitro and in vivo studies indicate that the nanoparticles display excellent anticancer activities upon light irradiation,showing great potential for cancer photodynamic therapy.This study provides a straightforward and effective approach for enhancing the photosensitivity of conventional photosensitizers via host–guest complexation-based FRET,which will open a new avenue for host–guest chemistry-based supramolecular theranostics.

Potential of photodynamic therapy in the management of infectious oral diseases

Photodynamic therapy(PDT)can take place in the presence of three elements:Light with an appropriate wavelength;a photosensitizer;and the presence of oxygen.This type of treatment is very effective overall against bacterial,viral and mycotic cells.In the last 10 years many papers have been published on PDT with different types of photosensitizers(e.g.,methylene blue,toluidine blue,indocyanine green,curcumin-based photosensitizers),different wavelengths(e.g.,460 nm,630 nm,660 nm,810 nm)and various parameters(e.g.,power of the light,time of illumination,number of sessions).In the scientific literature all types of PDT seem very effective,even if it is difficult to find a standard protocol for each oral pathology.PDT could be an interesting way to treat some dangerous oral infections refractory to common pharmacological therapies,such as candidiasis from multidrug-resistant Candida spp.

Light/pH dual controlled drug release"nanocontainer"alleviates tumor hypoxia for synergistic enhanced chemotherapy,photodynamic therapy and chemodynamic therapy

Photodynamic therapy(PDT)has significant advantages in treating primary tumors.However,the hypoxic tumor microenvironment hinders the generation of sufficient reactive oxygen species during PDT to effectively kill tumor cells,further greatly limiting the applications of PDT in cancer treatment.Herein,we reported a temperature/pH dual controlled drug delivery system LPC@PCN@PDA/Fe^(3+)-AS1411 based on a porous coordination network(PCN(Mn))coated with polydopamine(PDA)and modified with an aptamer AS1411.β-lapachone(LPC)was loaded inside the PCN(Mn)framework,and Fe^(3+)was attached to the surface of the PDA coating.These nanoparticles(NPs)exhibited excellent multimodal cancer therapeutic effects and tumor targeting ability with their photo-and chemodynamic properties.The therapeutic effect can be enhanced by the production of sufficient oxygen by the internal hydrogen peroxide,which improves the photodynamic effect of the photosensitizer PCN(Mn)and the chemotherapy effect ofβ-lapachone.Notably,the conversion of Fe^(2+)to Fe^(3+)in the tumor cells exerts the Fenton effect,which generates hydroxyl radicals that cause lipid peroxidation in tumor cells and induce apoptosis,thus enhancing the chemodynamic therapeutic effect.In vitro and in vivo experiments revealed that the NPs demonstrated specific tumor targeting,excellent inhibition effect on tumor growth,and biocompatibility.Together,our findings can help develop an intelligent multifunctional therapeutic nanoplatform for cancer therapy.

Anti-PD1 antibody and not anti-LAG-3 antibody improves the antitumor effect of photodynamic therapy for treating metastatic breast cancer

Photodynamic therapy(PDT)has limited effects in treating metastatic breast cancer.Immune checkpoints can deplete the function of immune cells;however,the expression of immune checkpoints after PDT is unclear.This study investigates whether the limited e±cacy of PDT is due to upregulated immune checkpoints and tries to combine the PDT and immune checkpoint inhibitor to observe the e±cacy.A metastatic breast cancer model was treated by PDT mediated by hematoporphyrin derivatives(HpD-PDT).The anti-tumor effect of HpD-PDT was observed,as well as CD4þT,CD8þT and calreticulin(CRT)by immunohistochemistry and immunofluorescence.Immune checkpoints on T cells were analyzed byflow cytometry after HpD-PDT.When combining PDT with immune checkpoint inhibitors,the antitumor effect and immune effect were assessed.For HpD-PDT at 100 mW/cm2 and 40,60 and 80 J/cm2,primary tumors were suppressed and CD4þT,CD8þT and CRT were elevated;however,distant tumors couldn't be inhibited and survival could not be prolonged.Immune checkpoints on T cells,especially PD1 and LAG-3 after HpD-PDT,were upregulated,which may explain the reason for the limited HpD-PDT effect.After PDT combined with anti-PD1 antibody,but not with anti-LAG-3 antibody,both the primary and distant tumors were signi-cantly inhibited and the survival time was prolonged,additionally,CD4þT,CD8þT,IFN-þCD4þT and TNF-þCD4þT cells were signi-cantly increased compared with HpD-PDT.HpD-PDT could not combat metastatic breast cancer.PD1 and LAG-3 were upregulated after HpD-PDT.Anti-PD1 antibody,but not anti-LAG-3 antibody,could augment the antitumor effect of HpD-PDT for treating metastatic breast cancer.

NIR-triggered on-site NO/ROS/RNS nanoreactor:Cascade-amplified photodynamic/photothermal therapy with local and systemic immune responses activation

Photothermal and photodynamic therapies(PTT/PDT)hold promise for localized tumor treatment,yet their full potential is hampered by limitations such as the hypoxic tumor microenvironment and inadequate systemic immune activation.Addressing these challenges,we present a novel near-infrared(NIR)-triggered RNS nanoreactor(PBNO-Ce6)to amplify the photodynamic and photothermal therapy efficacy against triple-negative breast cancer(TNBC).The designed PBNOCe6 combines sodium nitroprusside-doped Prussian Blue nanoparticles with Chlorin e6 to enable on-site RNS production through NIR-induced concurrent NO release and ROS generation.This not only enhances tumor cell eradication but also potentiates local and systemic antitumor immune responses,protecting mice from tumor rechallenge.Our in vivo evaluations revealed that treatment with PBNO-Ce6 leads to a remarkable 2.7-fold increase in cytotoxic T lymphocytes and a 62%decrease in regulatory T cells in comparison to the control PB-Ce6(Prussian Blue nanoparticles loaded with Chlorin e6),marking a substantial improvement over traditional PTT/PDT.As such,the PBNO-Ce6 nanoreactor represents a transformative approach for improving outcomes in TNBC and potentially other malignancies affected by similar barriers.

Tissue optical clearing enhances efficacy of vascular targeted photodynamic therapy of mouse dorsal skin

Vascular-targeted photodynamic therapy(V-PDT)is an effective treatment for port wine stains(PWS).However,repeated treatment is usually needed to achieve optimal treatment outcomes,possibly due to the limited treatment light penetration depth in the PWS lesion.The optical clearing technique can increase light penetration in depth by reducing light scattering.This study aimed to investigate the V-PDT in combination with an optical clearing agent(OCA)for the therapeutic enhancement of V-PDT in the rodent skinfold window chamber model.Vascular responses were closely monitored with laser speckle contrast imaging(LSCI),optical coherence tomography angiography,and stereo microscope before,during,and after the treatment.We further quantitatively demonstrated the effects of V-PDT in combination with OCA on the blood flow and blood vessel size of skin microvasculature.The combination of OCA and V-PDT resulted in significant vascular damage,including vasoconstriction and the reduction of blood flow.Our results indicate the promising potential of OCA for enhancing V-PDT for treating vascular-related diseases,including PWS.

Reduction of photodynamic damage of blood vessels in the protected region by(–)-epigallocatechin gallate

Photodynamic therapy(PDT)has been increasingly used in the clinical treatment of neoplastic,inflammatory and infectious skin diseases.However,the generation of reactive oxygen species(ROS)may induce undesired side effects in normal tissue surrounding the treatment lesion,which is a big challenge for the clinical application of PDT.To date,(–)-Epigallocatechin gallate(EGCG)has been widely proposed as an antiangiogenic and antitumor agent for the protection of normal tissue from ROS-mediated oxidative damage.This study evaluates the regulation ability of EGCG for photodynamic damage of blood vessels during hematoporphyrin monomethyl ether(Hemoporfin)-mediated PDT.The quenching rate constants of EGCG for the triplet-state Hemoporfin and photosensitized 1O2 generation are determined to be 6.8×10^(8)M^(−1)S^(−1),respectively.The vasoconstriction of blood vessels in the protected region treated with EGCG hydrogel after PDT is lower than that of the control region treated with pure hydrogel,suggesting an efficiently reduced photodamage of Hemoporfin for blood vessels treated with EGCG.This study indicates that EGCG is an efficient quencher for triplet-state Hemoporfin and 1O2,and EGCG could be potentially used to reduce the undesired photodamage of normal tissue in clinical PDT.

Effective Qubit Emerging from the Nanoheterointerface Two-Dimensional Electron Gas Photodynamics

An “Eigenstate Adjustment Autonomy” Model, permeated by the Nanosystem’s Fermi Level Pinning along with its rigid Conduction Band Discontinuity, compatible with pertinent Experimental Measurements, is being employed for studying how the Functional Eigenstate of the Two-Dimensional Electron Gas (2DEG) dwelling within the Quantum Well of a typical Semiconductor Nanoheterointerface evolves versus (cryptographically) selectable consecutive Cumulative Photon Dose values. Thus, it is ultimately discussed that the experimentally observed (after a Critical Cumulative Photon Dose) Phenomenon of 2DEG Negative Differential Mobility allows for the Nanosystem to exhibit an Effective Qubit Specific Functionality potentially conducive to (Telecommunication) Quantum Information Registering.

Clinical Study of Photodynamic Therapy for Upper Gastrointestinal Tract Cancers

Objective： To evaluate the clinical effectiveness and adverse effects of photodynamic therapy （PDT） for the upper gastrointestinal tract cancers. Methods： 56 patients with upper gastrointestinal cancers in different clinical stages were treated with PDT. Diode laser （630 nm） was used as the light source and the parameters were as follows： power density 200 to 400 mW/cm, energy density 100 to 300 J/cm. PHOTOFRIN was used as photosensitizer, which was given in a dose of 2 mg/kg intravenously 12-24 h before irradiation. Results： Evaluation of the 56 patients＇ therapeutic effectiveness showed that 6 patients （10.7%） had a complete response （CR）, 33 patients （58.9%） partial response （PR）, 12 patients （21.4%） mild response （MR）, and 5 patients （8.9%） no response （NR）. The total response rate （CR＋PR） was 69.6%. No patients had severe adverse effects in this group. Conclusion： PDT is an effective and safe palliative modality for upper gastrointestinal tract cancers.

Influence of Photodynamic Therapy on Apoptosis and Invasion of Human Cholangiocarcinoma QBC939 Cell Line

Objective To investigate the effect of photodynamic therapy(PDT) mediated by hematoporphyrin derivative(HPD) on apoptosis and invasion of cholangiocarcinoma QBC939 cell lines. Methods In vitro cultured cholangiocarcinoma QBC939 cell line was exposed to 2, 4, 6, 8, 10, 12, and 14 μg/ml HPD with 5, 10, and 15 J/cm2 light intensity, respectively. The optical density at 450 nm of the QBC939 cells was measured by CCK8 assay and its growth inhibition ratio was calculated. Flow cytometry and transwell migration assay were applied to detect cell apoptosis and invasion respectively. RT-PCR and immunocytochemistry analyses were used to detect expressions of vascular endothelial growth factor-C(VEGF-C), cyclooxygenase-2(COX-2), and proliferating cell nuclear antigen(PCNA). Enzyme-linked immunosorbent assay(ELISA) was carried out to examine the secretion of VEGF-C and COX-2 in QBC939 cells. Results Exposure to HPD-PDT can significantly suppress the growth of QBC939 cells(all P<0.05). HPD-PDT can promote apoptosis of QBC939 cells at the early stage. When the concentration of HPD was 2 μg/ml and light irradiation was 5 J/cm2, HPD-PDT had no obvious inhibitory effect on QBC939 cell growth, but can obviously inhibit cell invasion, and significant difference was observed between the HPD-PDT and control groups(P<0.01). The HPD-PDT can reduce the m RNA and protein expressions of VEGF-C, COX-2, and PCNA, and decrease the secretion of VEGF-C and COX-2 in QBC939 cells. Conclusion PDT could promote apoptosis and inhibit growth and invasion of cholangiocarcinoma cells QBC939 in vitro.

Recent Advances in Tumor Microenvironment Hydrogen Peroxide-Responsive Materials for Cancer Photodynamic Therapy

Photodynamic therapy(PDT),as one of the noninvasive clinical cancer phototherapies,suffers from the key drawback associated with hypoxia at the tumor microenvironment(TME),which plays an important role in protecting tumor cells from damage caused by common treatments.High concentration of hydrogen peroxide(H2O2),one of the hallmarks of TME,has been recognized as a double-edged sword,posing both challenges,and opportunities for cancer therapy.The promising perspectives,strategies,and approaches for enhanced tumor therapies,including PDT,have been developed based on the fast advances in H2O2-enabled theranostic nanomedicine.In this review,we outline the latest advances in H2O2-responsive materials,including organic and inorganic materials for enhanced PDT.Finally,the challenges and opportunities for further research on H2O2-responsive anticancer agents are envisioned.

Single NIR Laser-Activated Multifunctional Nanoparticles for Cascaded Photothermal and Oxygen-Independent Photodynamic Therapy

Inconvenient dual-laser irradiation and tumor hypoxic environment as well as limited judgment of treating region have impeded the development of combined photothermal and photodynamic therapies(PTT and PDT).Herein,Bi2Se3@AIPH nanoparticles(NPs)are facilely developed to overcome these problems.Through a one-step method,free radical generator(AIPH)and phase transition material(lauric acid,LA,44-46°C)are encapsulated in hollow bismuth selenide nanoparticles(Bi2Se3 NPs).Under a single 808-nm laser irradiation at the tumor area,hyperthermia produced by Bi2Se3 not only directly leads to cell death,but also promotes AIPH release by melting LA and triggers free radical generation,which could further eradicate tumor cells in hypoxic environments.Moreover,Bi2Se3 with high X-ray attenuation coefficient endows the NPs with high computed tomography(CT)imaging capability,which is important for treating area determination.The results exhibit that Bi2Se3@AIPH NPs possesses 31.2%photothermal conversion efficiency for enhanced PTT,ideal free radical generation for oxygen-independent PDT,and 37.77 HU mL mg?1 X-ray attenuation coefficient for CT imaging with high quality.Most importantly,the tumor growth inhibition rate by synergistic PTT,PDT,and following immunotherapy is 99.6%,and even one tumor disappears completely,which demonstrates excellent cascaded synergistic effect of Bi2Se3@AIPH NPs for the tumor therapy.

Photodynamic therapy vs radiofrequency ablation for Barrett's dysplasia: Efficacy,safety and cost-comparison

AIM:To compare effectiveness,safety,and cost of photodynamic therapy(PDT)and radiofrequency ablation(RFA)in treatment of Barrett’s dysplasia(BD).METHODS:Consecutive case series of patients undergoing either PDT or RFA treatment at single center by a single investigator were compared.Thirty-three patients with high-grade dysplasia(HGD)had treatment with porfimer sodium photosensitzer and 630 nm laser(130 J/cm),with maximum of 3 treatment sessions.Fifty-three patients with BD(47 with low-grade dysplasia-LGD,6 with HGD)had step-wise circumferential and focal ablation using the HALO system with maximum of 4 treatment sessions.Both groups received proton pump inhibitors twice daily.Endoscopic biopsies were acquired at 2 and 12 mo after enrollment,with 4-quadrant biopsies every 1 cm of the original BE extent.A complete histological resolution response of BD(CR-D)was defined as all biopsies at the last endoscopy session negative for BD.Fisher’s exact test was used to assess differences between the two study groups for primary outcomes.For all outcomes,a two-sided P value of less than 0.05 was considered to indicate statistical significance.RESULTS:Thirty(91%)PDT patients and 39(74%)RFA were men(P=0.05).The mean age was 70.7±12.2 and 65.4±12.7(P=0.10)year and mean length of BE was 5.4±3.2 cm and 5.7±3.2 cm(P=0.53)for PDT and RFA patients,respectively.The CR-D was(18/33)54.5%with PDT vs(47/53)88.7%with RFA(P=0.001).One patient with PDT had an esophageal perforation and was managed with non-surgical measures and no perforation was seen with RFA.PDT was five times more costly than RFA at our institution.The two groups were not randomized and had different BD grading are the limitations of the study.CONCLUSION:In our experience,RFA had higher rate of CR-D without any serious adverse events and was less costly than PDT for endoscopic treatment of BD.

Photodynamic therapy for high-grade dysplasia of bile duct via a choledochoscope

When a distal common bile duct neoplasm is at the stage of carcinoma in situ or high-grade dysplasia,it is difficult for the surgeon to decide whether to perform pancreaticoduodenectomy.Here we describe a patient with a progressive dysplastic lesion in the common bile duct,which developed from moderate-high to highgrade dysplasia in approximately 2 mo.The patient refused major surgery.Therefore,endoscopic-assisted photodynamic therapy was performed.The result at follow-up using a trans-T-tube choledochoscope showed that the lesion was completely necrotic.This report is the first to describe the successful treatment of highgrade dysplasia of the distal bile duct using photodynamic therapy via a choledochoscope.

Photodynamic therapy:Palliation and endoscopic technique in cholangiocarcinoma

Cholangiocarcinoma is the primary malignancy arising from the biliary epithelium.The disease is marked by jaundice,cholestasis,and cholangitis.Over 50 percent of patients present with advanced stage disease,precluding curative surgical resection as an option of treatment.Prognosis is poor,and survival has been limited even after biliary decompression.Palliative management has become the standard of care for unresectable disease and has evolved to include an endoscopic approach. Photodynamic therapy(PDT)consists of administration of a photosensitizer followed by local irradiation with laser therapy.Several studies conducted in Europe and the United States have shown a marked improvement in the symptoms of cholestasis,survival,and quality of life.This article summarizes the published experience regarding PDT for cholangiocarcinoma and the steps required to administer this therapy safely.

Human natural killer cells for targeting delivery of gold nanostars and bimodal imaging directed photothermal/photodynamic therapy and immunotherapy

Objective:To construct a novel nanoplatform GNS@CaCO3/Ce6-NK by loading the CaCO3-coated gold nanostars(GNSs)with Chlorin e6 molecules(Ce6)into human peripheral blood mononuclear cells(PBMCs)-derived NK cells for tumor targeted therapy.Methods:GNS@CaCO3/Ce6 nanoparticles were prepared and characterized by TEM and UV-vis.The cell surface markers and cytokines secretion of NK cells before and after loading the GNS@CaCO3/Ce6 nanoparticles were detected by Flow Cytometry(FCM)and ELISA.Effects of the GNS@CaCO3/Ce6-NK cells on A549 cancer cells was determined by FCM and CCK-8.Intracellular fluorescent signals of GNS@CaCO3/Ce6-NK cells were detected via Confocal laser scanning microscopic(CLSM)and FCM at different time points.Intracellular ROS generation of GNS@CaCO3/Ce6-NK cells under laser irradiation were examined by FCM.The distribution of GNS@CaCO3/Ce6-NK in A549 tumor-bearing mice were observed by fluorescence imaging and PA imaging.The combination therapy of GNS@CaCO3/Ce6-NK under laser irradiation were investigated on tumor-bearing mice.Results:The coated CaC03 shell on the surface of GNSs exhibited prominent delivery and protection effect of Ce6 during the cellular uptake process.The as-prepared multifunctional GNS@CaCO3/Ce6-NK cells possessed bimodal functions of fluorescence imaging and photoacoustic imaging.The as-prepared multifunctional GNS@CaCO3/Ce6-NK cells could actively target tumor tissues with the enhanced photothermal/photodynamic therapy and immunotherapy.Conclusions:The GNS@CaCO3/Ce6-NK shows effective tumor-targeting ability and prominent therapeutic efficacy toward lung cancer A549 tumor-bearing mice.Through fully utilizing the features of GNSs and NK cells,this new nanoplatform provides a new synergistic strategy for enhanced photothermal/photodynamic therapy and immunotherapy in the field of anticancer development in the near future.

Combined therapy with bevacizumab and photodynamic therapy for myopic choroidal neovascularization: A oneyear follow-up controlled study

AIMTo evaluate the efficacy and safety of a combined treatment for myopic choroidal neovascularization (CNV) using photodynamic therapy (PDT) and intravitreal bevacizumab and to compare it with intravitreal bevacizumab monotherapy.

Effects of integrin-targeted photodynamic therapy on pancreatic carcinoma cell

AIM:To investigate the effects of photodynamic therapy with quantum dots-arginine-glycine-aspartic acid(RGD)probe as photosensitizer on the proliferation and apoptosis of pancreatic carcinoma cells.METHODS:Construction of quantum dots-RGD probe as photosensitizer for integrin-targeted photodynamic therapy was accomplished.After cells were treated with photodynamic therapy(PDT),the proliferation of SW1990 cells were measured by methyl thiazolyl tetrazolium assay.Morphologic changes,cell cycle retardance and apoptosis were observed under fluoroscope and flow cytometry.The expression of myeloid cell leukemia-1(Mcl-1),protein kinase B(Akt)and tumor necrosis factor-related apoptosis-inducing ligand(TRAIL)mRNA were detected by reverse transcriptionpolymerase chain reaction.The amount of reactive oxygen species were also evaluated by fluorescence probe.RESULTS:The photodynamic therapy with quantum dots-RGD probe as photosensitizer significantly inhibited cell proliferation(P<0.01).Apoptotic cells and morphologic changes could be found under optical microscope.The FCM revealed PDT group had more significant cell apoptosis rate compared to control cells(F=130.617,P<0.01)and cell cycle G0/G1and S retardance(P<0.05)compared to control cells.The expression of Mcl-1 and Akt mRNA were down-regulated,while expression of TRAIL mRNA was up-regulated after cells treated with PDT.PDT group had more significant number of cells producing reactive oxygen species compared to control cells(F=3262.559,P<0.01).CONCLUSION:The photodynamic therapy with quantum dots-RGD probe as photosensitizer significantly inhibits cell proliferation and increases apoptosis in SW1990 cells.