Design,Construction And Application Of Antitumor Nanomedicines To Remodel Tumor Microenvironment

Chemotherapy is one of the major modalities of cancer treatment,which achieves superior anti-tumor efficacy.However,chemotherapeutic drugs are cytotoxic substances,which not only kill tumor cells,but also non-selectively kill normal cells,causing serious toxic side effects.Therefore,it is of great significance to develop tumor therapeutic drugs that can selectively kill tumor cells.The tumor microenvironment（TME）is a unique environment for the tumor development,and it differs markedly from that of normal tissues.Drugs targeting TME can not only specifically affect on tumor tissue,but also significantly reduce the toxic side effects on normal tissue.At present,the drugs targeting TME mainly achieve tumor therapy by responding to TME.For example,chemotherapeutic drugs can be made into prodrugs and released specifically in tumor cells in response to the slightly acidic environment;antitumor drugs loaded in nanocarriers were specifically released in tumor cells in response to the unique redox environment,selectively killing tumor cells without affecting normal cells.Although anti-tumor drugs that responding to tumor microenvironment to play an anti-cancer role provide a new opportunity for tumor selective therapy,but these drug systems do not change the survival environment of tumor cells and cannot fundamentally solve the problem of cancer therapy.In this case,remodeling the tumor microenvironment and transforming it into an environment that is not suitable for tumor occurrence and development has become a research hotspot in recent years.Therefore,in this work,we designed a series of nano drugs that could reshape the tumor microenvironment and fundamentally changed the microenvironment that was conducive to tumor survival,which effectively inhibited the occurrence and development of malignant tumors and did not affect normal tissues;in addition,these nano drugs had the function of killing tumor cells,playing a synergistic anti-cancer effect.This kind of nano drugs reshaped tumor microenvironment,providing a new idea for TME-based tumor therapy,and thus having great clinical transformation potential.The specific contents include the following aspects:1.An oligomeric hyaluronic acid-GX1 multi-target drug can induce tumor cells apoptosis by inhibiting angiogenesis.Abundant vascular system plays an important role in the rapid growth of tumor cells,which is a major feature of tumor microenvironment.As we all know,it is an effective anti-tumor strategy to inhibit the formation of neovascularization in tumor tissue to change the microvascular environment.For example,drugs can target the vascular endothelial growth factor（VEGF）receptor,on endothelial cells in tumor tissue,to inhibit neovascularization.However,the drugs only targeting VEGF are easy to produce drug resistance and off-target toxicity due to its single target.Therefore,in this work,we developed a multi-target drug that can target VEGF and CD44 receptors,which can play an anti-tumor role and effectively avoid the off target toxicity.Specifically,we covalently linked the peptide GX1（CGNSNPKSC）that targeting VEGF receptor with the oligomeric hyaluronic acid（o HA）that targeting CD44 receptor by amide condensation reaction to prepare the multi-target drug o HA-GX1.Benefited from the multiple carboxyl groups of o HA,multiple GX1 molecules were grafted to o HA,resulting in o HA-GX1 being a macromolecular drug and thus staying in the blood stream circulating for prolonged periods of time;moreover,due to the polyvalent design,o HA-GX1 could interact with overexpressed CD44 and VEGF receptors inside tumor tissues in a polyvalent fashion,thus suppressing the angiogenesis and killing tumor cells,ultimately effectively inhibiting tumor growth.The results of microtubule formation in vitro and CD31 immunostaining of tumor tissues showed that o HA-GX1 could significantly inhibit the formation of microtubules in vitro and angiogenesis in tumor tissue.The cytotoxicity test showed that o HA-GX1 also effectively inhibited the growth of co-SGC-7901 and co-HUVEC cells,and the IC₅₀of o HA-GX1 against two cells were significantly lower than those of free GX1,free o HA and o HA/GX1.After intravenous injection,the tumor inhibition rate（TIR）of50 mg·kg^-1 o HA-GX1 against SGC-7901 tumor-bearing nude mice reached 68.1%,2.7 times and 1.4 times higher than those of the free drug groups（GX1 or o HA）and o HA/GX1 group,respectively.Moreover,as the dose increased to 100 mg·kg^-1,the TIR increased further to 78.4%.During the 60-day experiment period,o HA-GX1could dramatically improve the survival rate of mice（100%）,while the mice in other administrated groups were dead in varying degrees.Notably,o HA-GX1 could maximally avoid off-target effect due to its polyvalent interactions with receptors,so it almost did not cause adverse effects;and since the component of o HA-GX1 were both biogenic compounds,it showed excellent biocompatibility.Overall,this polyvalent multi-target drug can remodel tumor vascular microenvironment and simultaneously kill tumor cells,providing a new strategy for inhibiting the growth of malignant tumors.2.Natural polyphenols-loaded crosslinked lipoic acid vesicles can prevent the metastasis of triple-negative breast cancer by inhibiting ECM degradation.The extracellular matrix（ECM）is one of the most important non-cellular components in tumor microenvironment.The degradation of ECM could directly promote the metastasis of tumor cells.Triple-negative breast cancer（TNBC）is an aggressive subtype of breast cancers,which is known for its high rate of metastasis.Due to the lack of therapeutic targets and the limited pharmacological therapeutic options,there is still a lack of effective means for the metastasis of TNBC in recent decades.Based on this,to inhibit the degradation of ECM of triple negative breast cancer,which prevent cells from breaking through the peripheral barrier to metastasize,may provide an effective method for the treatment of triple negative breast cancer metastasis.In this work,we constructed a kind of nanoparticles that could strongly inhibit the degradation of ECM.These nanoparticles effectively inhibited the metastasis of 4T1（triple negative breast cancer cells）by prevented cells breaking through the ECM.Specifically,a cross-linked nanodrug（EGCG@c LAVs）was prepared by loading natural polyphenol epigallocatechin gallate（EGCG）to（R）-（+）-lipoic acid（LA）carrier.When EGCG@c LAVs were absorbed into tumor cells,the disulfide bonds were cleaved by overexpressed glutathione（GSH）and EGCG was released.Since LA and EGCG could play a synergistic role in inhibiting extracellular matrix degradation and anti-tumor,EGCG@c LAVs would effectively inhibit the metastasis and growth of tumor cells.In vitro anti-metastasis test showed that EGCG@c LAVs could effectively inhibit the migration of 4T1 and the penetration of matrigel;the cytotoxicity test showed that EGCG@c LAVs effectively inhibited the growth of 4T1 cells,where IC₅₀^EGCG（85.1μM）)and IC₅^c ₀^LAVs（69.1μM）were 4.2 and 18.6 times lower than those of EGCG and c LAVs,respectively.The results of mice experiments show that when the intravenous injection dose of EGCG@c LAVs reached 120 mg·kg^-1,the tumor inhibition rate against 4T1 subcutaneous tumor bearing BALB/c mice was more than 80%,and the metastasis of 4T1 cells to the lung was effectively inhibited.Due to the strong anti-metastasis and anti-tumor ability,the survival rate of mice after EGCG@c LAVs treatment was significantly improved,and the survival rate of mice in 120 mg·kg^-1 dosage group was 100%on the 60th day.Notably,the nanocarriers and the loading drugs are natural compounds,so the constructed nanoparticles showed excellent biological safety.The nanoparticles we designed inhibit the degradation of extracellular matrix,which block the tumor cells metastasis from the source;and the nanoparticles have the function of killing tumor cells,which playing a role of synergetic inhibition of tumor metastasis.Therefore,this"kill two birds with one stone"design strategy provides a new method for the therapy of highly invasive triple negative breast cancer metastasis.3.Cross-linked lipoic acid vesicles with aspirin loading efficiently inhibit postsurgical cancer recurrence by suppressing postsurgical inflammation.Inflammation is one of the main characteristics of tumor microenvironment.It not only helps tumor cells escape the surveillance of immune system,but also promotes angiogenesis and tumor cell growth.The elimination of tumor associated inflammatory microenvironment is of great significance for tumor treatment.Surgical resection is the cornerstone of treatment for solid tumors,but surgery destroys the cascade feedback between inflammatory factors in wound tissue,resulting in imbalance of pro-inflammatory and anti-inflammatory cytokines secretion,which makes the postsurgical residual tumor cells in a high inflammatory microenvironment,thus promoting the recurrence of these cells.It is expected to fundamentally solve the problem of postoperative cancer recurrence by regulating the high inflammatory microenvironment and killing the residual tumor cells at the same time,but to the best of our knowledge,there is no relevant research report at present.Herein,we designed a cross-linked lipoic acid vesicle loading with clinical first-line non-steroidal anti-inflammatory drug aspirin（Asp）（Asp@c LANPs）.When entering tumor tissue,the disulfide bonds of Asp@c LANPs were cleaved by overexpressed glutathione（GSH）and Asp was released.Since LA and Asp could play a strongly synergistic role in anti-inflammatory and anti-tumor,Asp@c LANPs could effectively eliminate the postsurgical inflammatory microenvironment and kill the residual tumor cells.The results of inflammation test in vitro showed that Asp@c LANPs could effectively regulate the inflammatory factors of related cells in the inflammatory microenvironment,;the results of cytotoxicity showed that the IC₅₀^Asp of Asp@c LANPs against human large cell lung cancer cells NCI-H460 was102.5μm,which was 62.5 times lower than that of Asp alone.In vivo,we used NCI-H460 subcutaneous incomplete tumor resection model to simulate local recurrence.The results showed that after 7 times of administration,the tumor recurrence rate of mice in the 130 mg·kg^-1 Asp@c LANPs group was only 11.1%.Notably,after cessation of the administration,the tumor recurrence rate of mice in130 mg·kg^-1 Asp@c LANPs group in the 60 days experimental cycle was only 33.3%,while all mice in the chemotherapy drug cisplatin(3 mg·kg^-1)group occurred tumor recurrence.These results may be due to the elimination of the inflammatory microenvironment that was conducive to tumor recurrence after Asp@c LANPs treatment,while this could not come true in the chemotherapy drugs treatment group.Moreover,this nanodrug is constructed by biogenic lipoic acid and widely used anti-inflammatory drug aspirin in clinic,so it has good biological safety.Overall,this nanodrug can not only eliminate the postsurgical inflammatory microenvironment,but also kill the residual tumor cells,representing a new strategy for radical cure of postoperative tumor recurrence.