Research On Photodynamic Therapy And Tumor Markers Based On Gastrointestinal Tumors

Gastrointestinal tumors are the most common malignant tumors in our country,and the most common ones are esophageal cancer,gastric cancer and colorectal cancer,which seriously endanger people's lives and health.At present,surgical resection,endoscopic resection,radiotherapy and medical chemotherapy are still the main treatments for gastrointestinal malignant tumors.However,for some patients with advanced gastrointestinal tumors that cannot be eradicated,Photodynamic therapy(PDT)is a new type of tumor treatment method.It is characterized by low invasiveness,low toxicity,strong targeting,wide applicability,repeatability?and other advantages,gradually accepted by more and more patients.Compared with traditional treatment,PDT has unique advantages such as repeatable,less invasive,less side effects and excellent therapeutic effect.Although PDT has many unique advantages,it is limited in practical clinical applications due to tumor tissue hypoxia,poor tumor selectivity and limited tissue penetration depth.With the fast development of nanotechnology,researchers have developed a series of nanoparticles loaded with photosensitizers,such as polymer nanoparticles,upconversion nanoparticles,gold nanoparticles,mesoporous silica nanoparticles,inorganic quantum dots and so on,to try to solve the above problems related to photosensitizers molecules.Organic semiconductor polymers are polymer materials which have been widely used in organic optoelectronic devices.They have excellent optical properties,which are particularly suitable for the development of nanofluorescence techniques.Organic semiconductor polymer quantum dots(Pdots),an excellent nanomaterial,has many unique advantages for biomedical applications,including small size,high brightness,low toxicity,excellent water solubility,and no heavy metal components,which has attracted wide attention of researchers.At present,the Pdots loaded with photosensitizers have also been successfully applied to PDT,and have made periodic progress in the field of tumor therapy.Pdots can not only be used as a carrier to load hydrophobic photosensitizers to solve the problem of solubility of photosensitizers.It can also be used as a substrate for absorbing light and transferring energy to photosensitizers,thus amplifying the production of ROS and finally achieving the goal of killing cancer cells.Although Pdots loaded with photosensitizers can effectively exert the photodynamic effect while achieving tumor fluorescence imaging,the following problems should be properly solved if we intent to apply it to the clinical treatment of tumors: Severe photoallergic reactions;Limited depth of tissue penetration.To figure out these problems,our study intends to select the semiconductor polymer PFDTBT whose absorption spectrum located in the green light region.And its tissue penetration depth is increased compared with most semiconductor polymers whose absorption spectrum is in the blue light region.Secondly,the semiconductor polymer was used as the substrate to absorb light,and selected the matched photosensitizer molecules Ce6(Dihydroporphyrin e6)and optical switch molecule BTE to prepare Pdots of light switch by nano-precipitation method.Using the conversion of absorption spectra of light-switch molecules under different light source irradiation conditions,interference in fluorescence resonance energy transfer(FRET)between semiconductor polymer and photosensitizer molecule,and emission spectrum of photosensitizer molecules Ce6,achieved flexible regulation of Pdots-mediated photodynamic effects,that is,the photodynamic therapy effect is exerted(on)under the irradiation condition of the excitation light source,but the photodynamic therapy effect cannot be exerted(off)under the irradiation condition of the non-excitation light source,so as to achieve the purpose of ablation of tumor tissue and reducing the photoallergic reaction.In order to achieve the above purpose,we synthesized Ce6-doped Pdots containing BTE-free semiconductor polymer PFDTBT without photoswitching property,photosensitizer Ce6 and PSMA and re-precipitated,containing BTE semiconductor polymer with photoswitching property PFDTBT,Ce6-BTE-doped Pdots re-precipitated by photosensitizer Ce6,photoswitching molecules BTE and PSMA,and characterized by dynamic light scattering instrument,Zeta potentiometer and transmission electron microscope.The results show that the two Pdots are similar in size,similar in potential,and uniform in shape,which is suitable for carrying out subsequent biological experiments.Subsequently,we examined the sensitivity and repeatability of Ce6-BTE-doped Pdots by detecting the changes in the absorption and emission spectra of BTE and Ce6-BTE-doped Pdots under ultraviolet and green light irradiation-respectively,and the changes in the emission spectrum peak after multiple cycles of ultraviolet and green light irradiation.The sensitivity and repeatability of doped Pdots optical switch properties.The results show that Ce6-BTE-doped Pdots has good optical switch sensitivity and repeatability.After that,using ADMA as a probe to detect the yield of active oxygen,the active oxygen yields of the two Pdots under ultraviolet and green light irradiation were detected.In addition,in order to detect the effect of in vitro photodynamic therapy of the two Pdots,we detected the two Pdots through cytotoxicity experiments,cell fluorescence imaging,MTT experiment of ultraviolet and green light group irradiation,LDH release experiment,and Annexin V-FITC/PI staining the effect of in vitro photodynamic therapy.The results show that Ce6-BTE-doped Pdots has good biocompatibility,and has an in vitro photodynamic therapy effect similar to Ce6-doped Pdots under green light irradiation,and the phototoxicity under ultraviolet irradiation is much lower than Ce6-doped Pdots,the experimental results are basically consistent with our purpose of constructing nanoparticles with optical switching properties.Above all,our study intends to construct the Pdots with light switch regulation and apply it to biological research at the in vitro level.This nanoplatform is helpful to solve the difficult problems such as severe photoallergic reaction and limited tissue penetration depth.This study has great significance for improving the therapeutic effect of PDT and reducing the occurrence of collateral damage,and provides a new idea and reliable basis for truly realizing the clinical application of PDT.Tumors of the digestive system usually have no obvious adverse symptoms in the early stage and are not easy to be detected.When they are discovered,they are mostly in the middle and late stages.Therefore,the early diagnosis of gastrointestinal tumors has always been a research hotspot.Compared with traditional gastroscopy,colonoscopy,barium meal imaging and other inspection techniques,tumor marker detection has many advantages such as simple,fast,non-invasive,and accurate,and it play an important role in clinical diagnosis and treatment.Nuclear paraspeckle assembly transcript 1(NEAT1)is a new type of lncRNA,which has been reported to be abnormally expressed in various types of digestive system tumors,without clear clinical significance.Therefore,this meta-analysis aims to evaluate the effect of lncRNA NEAT1 on the prognosis and clinical parameters of digestive system tumors.Related literatures were searched in online databases included Pub Med,Embase and Web of Science.The relationship between NEAT1 expression and overall survival(OS)of digestive system cancer patients was evaluated by the pooled hazard ratio(HR)and the corresponding 95% confidence interval(CI).The stability and publication bias of the research results were verified by sensitivity analysis,Begg and Egger test results.Odds ratio(OR)and 95%CI was used to evaluate the correlation between NEAT1 expression and clinical parameters of cancer patients.A total of 12 related published papers were included.Compared with patients with low NEAT1 expression,patients with high NEAT1 expression had worse prognosis(HR = 1.64,95%CI: 1.41-1.91).Whether it was univariate analysis(HR =1.90,95%CI:1.65-2.20)or multivariate analysis(HR = 1.56,95%CI:1.30-1.88),high NEAT1 expression was associated with poor OS.Sensitivity analysis confirmed the reliability of the results.The results of Begg and Egger tests showed that there was no significant publication bias in this meta-analysis.In addition,the high expression level of NEAT1 was significantly associated with lymph node metastasis(OR = 2.70,95%CI:2.02-3.61),distant metastasis(OR = 3.01,95%CI:1.97-4.59)and tumor stage(OR = 3.04,95%CI:2.32-3.99)but there was no significant correlation between the patient's age(OR = 0.91,95%CI:0.65-1.26),sex(OR =1.04,95%CI:0.81-1.33),tumor size(OR = 1.84,95%CI:0.88-3.88)and tumor differentiation degree(OR = 0.86,95%CI:0.51-1.44).In summary,NEAT1 can be used as a potential biomarker to predict the prognosis of patients with digestive system tumors,which is worth verifying in clinical practice.