Apoptotic pathways as a therapeutic target for colorectal cancer treatment

Colorectal cancer is the second leading cause of death from cancer among adults. The disease begins as a benign adenomatous polyp, which develops into an advanced adenoma with high-grade dysplasia and then progresses to an invasive cancer. Appropriate apoptotic signaling is fundamentally important to preserve a healthy balance between cell death and cell survival and in maintaining genome integrity. Evasion of apoptotic pathway has been established as a prominent hallmark of several cancers. During colorectal cancer development, the balance between the rates of cell growth and apoptosis that maintains intestinal epithelial cell homeostasis gets progressively disturbed. Evidences are increasingly available to support the hypothesis that failure of apoptosis may be an important factor in the evolution of colorectal cancer and its poor response to chemotherapy and radiation. The other reason for targeting apoptotic pathway in the treatment of cancer is based on the observation that this process is deregulated in cancer cells but not in normal cells. As a result, colorectal cancer therapies designed to stimulate apoptosis in target cells would play a critical role in controlling its development and progression. A better understanding of the apoptotic signaling pathways, and the mechanisms by which cancer cells evade apoptotic death might lead to effective therapeutic strategies to inhibit cancer cell proliferation with minimal toxicity and high responses to chemotherapy. In this review, we analyzed the current understanding and future promises of apoptotic pathways as a therapeutic target in colorectal cancer treatment.

High expression of anti-apoptotic protein Bcl-2 is a good prognostic factor in colorectal cancer: Result of a metaanalysis

AIM To systematically evaluate the prognostic-predictive capability of Bcl-2 in colorectal cancer(CRC).METHODS A systematic literature search was conducted using Pub Med,Web of Science and EMBASE databases. Any eligible study must meet the following criteria:(1) bcl-2 expression was evaluated in human CRC tissues by immunohistochemistry;(2) assessment of the relationships between bcl-2 expression and overall survival(OS),disease free survival(DFS),recurrent free survival(RFS) or clinic-pathological characteristics of CRC was included;(3) sufficient information was provided to estimate the hazard ratio(HR) or odds ratio and their 95% confidence intervals(CIs); and(4) the study was published in English. The impact of Bcl-2 expression on survival of CRC patients were evaluated through this meta-analysis.RESULTS A total of 40 eligible articles involving 7658 patients were enrolled in our final analysis. We drew the conclusion that Bcl-2 high expression was significantly correlated with favorable OS(pooled HR = 0.69,95%CI: 0.55-0.87,P = 0.002) and better DFS/RFS(pooled HR = 0.65,95%CI: 0.50-0.85,P = 0.001). Additionally,the subgroup analysis suggested that Bcl-2 overexpression was significantly associated withprognosis(OS) especially in patients came from Europe and America but not Asian and patients who did not receive any adjuvant therapy before surgery. Finally,our present results indicated that expression of bcl-2 protein was associated with high differentiation grade and A/B Ducks' stage. CONCLUSION Bcl-2 high expression was significantly correlated with favorable OS and better DFS/RFS. Hence,we propose that Bcl-2 may be a valuable prognostic-predictive marker in CRC.

Pro-apoptotic and anti-proliferative effects of Physalis angulata leaf extract on retinoblastoma cells

AIM: To investigate the effect of Physalis angulata leaf extract on apoptotic and proliferation of retinoblastoma cells. Despite several previous studies evidencing the anticancer potential of Physalis angulata;however, certain study that proves its benefits in retinoblastoma cancer cells has been limited.METHODS: This study utilizes an in-vitro experimental study by applying Y79 human retinoblastoma cell line culture obtained from the American Type Culture Collection(ATCC;10801 University Boulevard Manassas, VA 20110, USA). The cell was divided into 4 groups. Group I was the control group without the administration of Physalis angulata leaf extract. Whereas, group II, II and IV are engaged with 25, 50, and 100 μg/mL of Physalis angulata leaf extract respectively. After a 24 h incubation, an examination with microtetrazolium(MTT) cell proliferation assay and Annexin V apoptosis detection was conducted. Statistical analysis was performed with the Tukey test.RESULTS: Physalis angulata leaf extract improved apoptosis and significantly reduced the number of living cells in retinoblastoma cells, along with the increase in the given dose. Based on the Tukey test, a significant difference was found in the treatment group at 50 μg/mL(P=0.025) and 100 μg/mL(P=0.001) in the measurement of apoptosis. Proliferation measurements also indicated a significant decrease in the number of living cells in the 50μg/m L treatment group(P=0.004), and in the 100 μg/mL treatment group(P=0.000). Meanwhile, a dose of 25 μg/mL indicated insignificant difference in the two measurements. Improved apoptosis and decreased number of living cells occured at a dose of 100 μg/mL. Decreased number of living cells(in the measurement of proliferation) was due to the inhibited proliferation or improved apoptosis.CONCLUSION: Physalis angulata leaf extract improve apoptosis in retinoblastoma cell culture, requiring further research to inhibit proliferation.

APOPTOTIC THRESHOLD OF ADRIAMYCIN AND CISPLATIN INHEPATOCELLULAR CARCINOMA

Objective: To investigate the apoptotic threshold ofadriamycin (ADM) and cisplatin (CDDP) onhepatocellular carcinoma (HCC). Methods: Sensitivitiesof ADM and CDDP on HCC were studied by primarycell culture. Results: The apoptotic threshold of ADMand CDDP were 1.0 μg/ml and 1.5μg/ml respectively (itsclinical dosage was 20 mg and 30 mg respectively).Conclusion: Understanding apoptotic threshold ofanticancer drugs may reduce clinical dosages ofanticancer drugs and reduce the incidence of multidrugresistance (MDR).

Methanolic extract of Clausena excavata promotes wound healing via antiinflammatory and anti-apoptotic activities

Objective: To investigate the anti-inflammatory properties of methanolic extract of Clausena excavata in lipopolysaccharide(LPS)-activated macrophages(J774 A.1) and the effect on skin wound in a rat model through determining cytokine levels and gene expressions. Methods: The effects of methanolic extract of Clausena excavata on in vitro viability and TNF-α, IL-6, IL-10, and nitric oxide release by LPS-activated J774 A.1 cells were determined. In addition, relative expressions of BAX, BCL-2 and COX-2 genes were examined in healed wounds of rats. Results: The methanolic extract of Clausena excavata was not toxic to J774 A.1 cells at the highest dose of 400 μg/m L. It decreased levels of TNF-α and IL-6, while increasing IL-10 level in LPSactivated J774 A.1 cells and in the healed wounds of rats. The methanolic extract of Clausena excavata also inhibited nitric oxide production in LPS-activated J774 A.1 cells. The BAX and COX-2 genes were downregulated while the BCL-2 gene was upregulated in the healed wound of rats. Conclusions: The methanolic extract of Clausena excavata promotes wound healing via its anti-inflammatory and anti-apoptotic activities.

Short term apoptotic activity of intravitreal bevacizumab on rabbit retina

AIM:To evaluate the safety and the short term apoptotic activity of intravitreai bevacizumab in rabbit eyes by histopathological analysis.METHODS:Twenty-eight eyes of 14 rabbits were divided into three groups:8 rabbits in group 1 and 3rabbits in each of group 2 and group 3.Intravitreai bevacizumab(1.25mg/0.05mL)was applied to the right eyes of each subject in group 1 and group 2(11 eyes)and the same volume of saline was applied to the left eyes of each subject in group 1 and group 3(11 eyes).The left eyes in group 2 and the right eyes in group 3were left untreated and used as control.Enucleated eyes were used for histopathologic analyses.RESULTS:After immunohistochemical staining with caspase-3 and p53,there was no histological evidence of toxicity to the retina and the optic nerve in any of the sections that were analyzed in all three groups.In addition,vascular endothelial cells located at the retina and the optic nerve tissues in all groups showed a similar staining pattern with caspase-3 and p53.CONCLUSION:Our study showed that intravitreai bevacizumab with the dose of 1.25mg/0.05mL caused no histological signs of toxicity or apoptotic activity on the rabbit retina.

Cloning and sequencing of a DNA fragment encoding N37 apoptotic peptide derived from p53

Objective It was reported that p53 apoptotic peptide (N37) could inhibit p73 gene through being bound with iASPP,which could induce tumor cell apoptosis. To further explore the function of N37,we constructed the cloning plasmid of DNA fragment encoding p53 (N37) apoptotic peptide by using DNA synthesis and molecular biology methods. Methods According to human p53 sequence from the GenBank database,the primer of p53(N37) gene was designed using Primer V7.0 software. The DNA fragment encoding p53 (N37) apoptotic peptide was amplified by using self-complementation polymerase chain reaction (PCR) method and cloned into the pGEM-T Easy vector. The constructed plasmid was confirmed by endonuclease analysis and sequencing. Results The insertion of objective DNA fragment was confirmed by plasmid DNA enzyme spectrum analysis. p53(N37)gene was successfully synthesized chemically in vitro. The sequencing result of positive clone was completely identical to the human p53(N37) sequence in GenBank using BLAST software (http://www.ncbi.nlm.nih.gov/cgi-bin /BLASTn). Conclusion The cloning of DNA fragment encoding p53(N37) apoptotic peptide was constructed by using DNA synthesis and pGEM-T Easy cloning methods. With the constructed plasmid,we could further investigate the function of N37 peptide.

S100b protects IMR-32 cells against Ab(1-42) induced neurotoxicity via modulation of apoptotic genes expression

Amyloid beta (1-42) peptide is considered responsible for the formation of senile plaques that accumulate in the brain of patients with Alzheimer’s disease (AD). In the past years considerable attention has been focused on identifying new protective substances that prevent or almost retard the appearance of amyloid beta (1-42)-related neurotoxic effects. In this study, human neuroblastoma cells (IMR-32) was used as system model to evaluate the protective role of S100b, a neurotrophic factor and neuronal survival protein, that is highly expressed by reactive astrocytes in close vicinity of beta-amyloid deposits, against amyloid beta (1-42)-dependent toxicity. Our results show that at nanomolar concentrations, S100b protects cells against Aβmediated cytotoxicity, as assessed by MTS vitality test. The protective mechanism seems to be related to the effect on bcl-2 (an anti-apoptotic gene) expression, which is highly down-regulated by amyloid beta (1-42) treatment, while resulted more expressed in the presence of S100b. On the contrary, Bax, a proapoptotic gene, resulted down-regulated by the treatment with S100 compared with the results obtained in the presence of amyloid beta (1-42) peptide. However, at micromolar doses, S100b is toxic for IMR-32 cells and its toxicity adds to that of the Aβpeptide, suggesting that additional molecular mechanisms may be involved in theneurotoxic process.

Diarrhea and Hypokalemic Rhabdomyolysis Due to Apoptotic Colitis as the Initial Manifestation of Common-Variable Immunodeficiency in an Adolescent

We present the case of an adolescent who presented with rhabdomyolysis due to severe hypokalemia arising from chronic diarrhea. Initial evaluation for celiac disease, known to present in this manner, was negative. Further evaluation with colonoscopy showed a normal appearing colon but biopsies showed a significant number of apoptotic cells in the mucosal crypts supporting a diagnosis of apoptotic colitis. Investigation into the cause of apoptotic colitis resulted in a diagnosis of common variable immune deficiency due to a defect in the inducible T-cell costimulator (ICOS) gene. Physicians should be aware of this uncommon condition and the importance of mucosal biopsy despite the presence of normal appearing mucosa.

Effect of Kang Ai injection + conventional chemotherapy on tumor markers, apoptotic molecules and immune response in patients with advanced NSCLC

Objective: To study the effects of Kang Ai injection + conventional chemotherapy on tumor markers, apoptotic molecules and immune response in patients with advanced non-small cell lung cancer (NSCLC). Methods: Patients diagnosed as advanced NSCLC in our hospital during March 2015 - October 2017 were randomly divided into the experimental group receiving Kang Ai injection + conventional chemotherapy and the control group receiving conventional chemotherapy. The contents of tumor markers, apoptotic molecules and immunologic cytokines in serum and the contents of immune cells in peripheral blood were determined before and after chemotherapy. Results: after chemotherapy, the content of CEA, CYFRA21-1, SCC-Ag, GDF15 and Livin in the serum of the two groups decreased significantly, and the content of PDCD5, P53 and Bax increased significantly, and the content of CEA, CYFRA21-1, SCC-Ag, GDF15, Livin in the serum of the experimental group were lower than those of the control group, and the content of PDCD5, P53 and Bax were higher than those of the control group;the content of CD3+ and CD4+ cells in peripheral blood and the content of IFN-γ, IL-2 in serum of control group significantly decreased, whereas the content of CD8+ cells in peripheral blood and the content of IL-4, IL-5 in serum significantly increased after chemotherapy;while the content of CD3+ and CD4+ cells in peripheral blood and the content of IFN-γ, IL-2 in serum of experimental group significantly increased, whereas the content of CD8+ cells in peripheral blood and the content of IL-4, IL-5 in serum significantly decreased after chemotherapy. Conclusion: Kang Ai injection + conventional chemotherapy in the treatment of advanced NSCLC can more significantly decrease the serum tumor markers, regulate the secretion of apoptotic molecules and anti-tumor immune response than conventional chemotherapy.

Correlation of serum apoptotic molecule and cytokine levels with cognitive function in epileptic patients

Objective:To investigate the correlation of serum apoptotic molecule and cytokine levels with cognitive function in epileptic patients.Methods: 78 adult epileptic patients admitted to our hospital between December 2016 and December 2018 were selected as the epilepsy group, and 50 normal people who underwent physical examination in our hospital during the same period were selected as the normal control group. The differences in serum levels of apoptotic molecules [bcl-1, bax, survivin, caspase-3, caspase-4 and caspase-10], inflammatory factors [interleukin-1β (IL-1β), interleukin-2 (IL-2), tumor necrosis factor (TN-α) and high mobility group protein B1 (HMGB1)], oxidative stress indexes [advanced oxidation protein product (AOPP), malondialdehyde (MDA) and glutathione peroxidase (GSH-Px)] and adipokines [adiponectin (APN) and leptin] as well as Mini-Mental State Examination (MMSE) scores were compared between the two groups, and Pearson test was used to evaluate the correlation of serum apoptotic molecule and cytokine levels with cognitive function in patients with epilepsy.Results: Serum bcl-1 and survivin levels in the epilepsy group were lower than those in the normal control group, while bax, caspase-3, caspase-4 and caspase-10 levels were higher than those in the normal control group;serum IL-1β, IL-2, TNF-α and HMGB1 levels were all higher than those in the normal control group;serum AOPP and MDA levels were higher than those in the normal control group, while GSH-Px level was lower than that in the normal control group;serum APN level was lower than that in the normal control group, while Leptin level was higher than that in the normal control group;MMSE score was significantly lower than that in the normal control group (P<0.05). Pearson test showed that the serum levels of apoptotic molecules, inflammatory factors, oxidative stress indexes and adipokines in epileptic patients were directly correlated with MMSE score (P<0.05).Conclusion:The cognitive function of epileptic patients is affected by apoptosis, inflammatory stress response, adipokine expression and other factors. Active regulation of the above internal environment factors may be one of the means to improve the cognitive status of epileptic patients.

Evaluating the Importance of Apoptotic Index, Mitotic Index and Turnover Index in Premalignant and Malignant Lesions of Cervix

Aim: To evaluate the premalignant and malignant lesions of the uterine cervix on light microscopy for apoptosis. To calculate and correlate the apoptotic index (AI), mitotic index (MI) and turnover index of the lesions. Materials and methods: A 2-year retrospective (November 2007 to October 2009) and 1-year prospective study (November 2009 to October 2010). A total of 95 cases of premalignant and malignant lesions of cervix were studied. The hematoxylin-eosin stained slides were screened for apoptosis under oil immersion lens. Apoptotic index (AI) was calculated as the number of Apoptotic cells and Apoptotic bodies, expressed as percentage of total no. of tumour cells counted in each case. Mitotic index (MI) was calculated by counting mitosis among 1000 tumour cells. Turnover index (TOI) was obtained by adding MI and AI, i.e., (TOI = MI + AI). After calculating, all these indices were correlated with different grades of the cervical lesions. Results: Premalignant lesions were divided into four subgroups. On statistical analysis, it was found that the difference in the apoptotic indices and turnover indices in all the four subgroups was not statistically significant. However for mitotic indices, significant statistical difference was found in Subgroup II (mild dysplasia vs. moderate dysplasia) with a p value of 0.03 and in subgroup IV (squamous metaplasia vs. moderate/severe dysplasia) with a p value of 0.0005. Within the malignant group, we compared well differentiated with less well differentiated subgroup. Statistical analysis revealed a significant difference in TOI between the two subgroups of malignant tumours (p = 0.04). Statistical comparison between premalignant and malignant group of lesions showed a highly significant difference between the AI, MI and TOI with p value of 0.0001. Conclusion: We conclude that proliferative and apoptotic indices are useful in distinguishing between benign and malignant lesions of the cervix. Proliferative activity of a lesion is a reliable indicator of its malignant potential and together with apoptotic count gives an idea about the net growth of a tumour.

Apoptotic vesicles rejuvenate mesenchymal stem cells via Rab7-mediated autolysosome formation and alleviate bone loss in aging mice

Aging skeletons display decreased bone mass,increased marrow adiposity,and impaired bone marrow mesenchymal stem cells(MSCs).Apoptosis is a programmed cell death process that generates a large number of apoptotic vesicles(apoVs).Dysregulated apoptosis has been closely linked to senescence-associated diseases.However,whether apoVs mediate agingrelated bone loss is not clear.In this study,we showed that young MSC-derived apoVs effectively rejuvenated the nuclear abnormalities of aged bone marrow MSCs and restored their impaired self-renewal,osteo-/adipo-genic lineage differentiation capacities via activating autophagy.Mechanistically,apoptotic young MSCs generated and enriched a high level of Ras-related protein 7(Rab7)into apoVs.Subsequently,recipient aged MSCs reused apoV-derived Rab7 to restore autolysosomes formation,thereby contributing to autophagy flux activation and MSC rejuvenation.Moreover,systemic infusion of young MSC-derived apoVs enhanced bone mass,reduced marrow adiposity,and recused the impairment of recipient MSCs in aged mice.Our findings reveal the role of apoVs in rejuvenating aging-MSCs via restoring autolysosome formation and provide a potential approach for treating age-related bone loss.

The miR-21-5p enriched in the apoptotic bodies of M2 macrophage-derived extracellular vesicles alleviates osteoarthritis by changing macrophage phenotype

Macrophages (Mφs) play a crucial role in the pathological progression of osteoarthritis (OA) by regulating inflammation and tissue repair. Decreasing pro-inflammatory M1-Mφs and increasing anti-inflammatory M2-Mφs can alleviate OA-related inflammation and promote cartilage repair. Apoptosis is a natural process associated with tissue repair. A large number of apoptotic bodies (ABs), a type of extracellular vesicle, are produced during apoptosis, and this is associated with a reduction in inflammation. However, the functions of apoptotic bodies remain largely unknown. In this study, we investigated the role of M2-Mφs-derived apoptotic bodies (M2-ABs) in regulating the M1/M2 balance of macrophages in a mouse model of OA. Our data show that M2-ABs can be targeted for uptake by M1-Mφs, and this reprograms M1-to-M2 phenotypes within 24 h. The M2-ABs significantly ameliorated the severity of OA, alleviated the M1-mediated pro-inflammatory environment, and inhibited chondrocyte apoptosis in mice. RNA-seq revealed that M2-ABs were enriched with miR-21–5p, a microRNA that is negatively correlated with articular cartilage degeneration. Inhibiting the function of miR-21–5p in M1-Mφs significantly reduced M2-ABs-guided M1-to-M2 reprogramming following in vitro cell transfection. Together, these results suggest that M2-derived apoptotic bodies can prevent articular cartilage damage and improve gait abnormalities in OA mice by reversing the inflammatory response caused by M1 macrophages. The mechanism underlying these findings may be related to miR-21-5p-regulated inhibition of inflammatory factors. The application of M2-ABs may represent a novel cell therapy, and could provide a valuable strategy for the treatment of OA and/or chronic inflammation.

Regulation of apoptotic signal transduction pathways by the heat shock proteins

The study about apoptotic signal transductions has become a project to reveal the molecular mechanisms of apoptosis. Heat shock proteins (hsps), which play an important role in cell growth and apoptosis, have attracted great attentions. A lot of researches have showed there is a hsps superfamily including hsp90, hsp70, hsp60 and hsp27, etc., which regulates the bio-logical behaviors of cells, particularly apoptotic signal transduction in Fas pathway, JNK/SAPK pathway and caspases pathway at different levels, partly by the function of molecular chaperone.

Identification of four caspase genes from Spodoptera exigua (Lepidoptera: Noctuidae) and their regulations toward different apoptotic stimulations

Apoptosis plays critical roles in multiple biological processes in multicellular organisms.Caspases are known as important participators and regulators of apoptosis.Here,four novel caspase genes of Spodoptera exigua were cloned and characterized which were designated as SeCasp-1,SeCasp-6,ScCasp-7 and SeCasp-S.Analysis of the putative encoded protein sequences of these SeCasps indicated that SeCasp-1 and ScCasp-7 were possible homologs of executor caspases;SeCasp-8 was a possible homolog of initiator caspases;and SeCasp-6 was a unique caspase of S.exigua that shares low similarity with all the identified insect caspases.Based on baculovirus expression system analyses,SeCasp-1 exhibited similar caspase activity to human caspase-1,-3,-4,-6,-8 and-9;SeCasp-6 presented similar caspase activity to human caspase-2,-3,-4,-6,-8 and-9;SeCasp-7 exhibited similar caspase activity to human caspase-2,-3 and-6;and SeCasp-8 presented similar caspase activity only to human caspase-8.Induction with diiTcrent chemicals revealed that SeCasp-1 showed extreme upregulation after 24 h in the treated fat body cell line(IOZCAS-Spex-II)of S.exigua.Developmental expression analysis revealed that SeCasp-1 was highly transcribed in the larval stages,while SeCasp-6,SeCasp-7,SeCasp-H were down-regulated.The in vivo detection of the relative expression levels of SeCasps in S.eixgua larvae inoculated with different pathogens suggested that SeCasp-J was sensitive to Bacillus thuringiensis infection and that SeCasp-6 was sensitive to baculovirus infection.SeCasp-7 and SeCasp-H showed slight changes under either in vitro chemical apoptosis induction or in vivo pathogen infection.

Engineered neutrophil apoptotic bodies ameliorate myocardial infarction by promoting macrophage efferocytosis and inflammation resolution

Inflammatory response plays a critical role in myocardial infarction(MI)repair.The neutrophil apoptosis and subsequent macrophage ingestion can result in inflammation resolution and initiate regeneration,while the therapeutic strategy that simulates and enhances this natural process has not been established.Here,we constructed engineered neutrophil apoptotic bodies(eNABs)to simulate natural neutrophil apoptosis,which regulated inflammation response and enhanced MI repair.The eNABs were fabricated by combining natural neutrophil apoptotic body membrane which has excellent inflammation-tropism and immunoregulatory properties,and mesoporous silica nanoparticles loaded with hexyl 5-aminolevulinate hydrochloride(HAL).The eNABs actively targeted to macrophages and the encapsulated HAL simultaneously initiated the biosynthesis pathway of heme to produce anti-inflammatory bilirubin after intracellular release,thereby further enhancing the anti-inflammation effects.In in vivo studies,the eNABs efficiently modulated inflammation responses in the infarcted region to ameliorate cardiac function.This study demonstrates an effective biomimetic construction strategy to regulate macrophage functions for MI repair.

Apoptotic regulation and tRNA

Apoptotic regulation is critical to organismal homeostasis and protection against many human disease processes such as cancer.Significant research efforts over the past several decades have illuminated many signaling molecules and effecter proteins responsible for this form of programmed cell death.Recent evidence suggests that transfer RNA(tRNA)regulates apoptotic sensitivity at the level of cytochrome c-mediated apoptosome formation.This finding unexpectedly places tRNA at the nexus of cellular biosynthesis and survival.Here we review the current understanding of both the apoptotic machinery and tRNA biology.We describe the evidence linking tRNA and cytochrome c in depth,and speculate on the implications of this link in cell biology.

Programming of macrophages by UV-irradiated apoptotic cancer cells inhibits cancer progression and lung metastasis

Apoptotic cell clearance by phagocytes is essential in tissue homeostasis.We demonstrated that conditioned medium(CM)from macrophages exposed to apoptotic cancer cells inhibits the TGFβ1-induced epithelial–mesenchymal transition(EMT),migration,and invasion of cancer cells.Apoptotic 344SQ(ApoSQ)cell-induced PPARγactivity in macrophages increased the levels of PTEN,which was secreted in exosomes.Exosomal PTEN was taken up by recipient lung cancer cells.ApoSQ-exposed CM from PTEN knockdown cells failed to enhance PTEN in 344SQ cells,restore cellular polarity,or exert anti-EMT and anti-invasive effects.The CM that was deficient in PPARγligands,including 15-HETE,lipoxin A4,and 15d-PGJ2,could not reverse the suppression of PPARγactivity or the PTEN increase in 344SQ cells and consequently failed to prevent the EMT process.Moreover,a single injection of ApoSQ cells inhibited lung metastasis in syngeneic immunocompetent mice with enhanced PPARγ/PTEN signaling both in tumorassociated macrophages and in tumor cells.PPARγantagonist GW9662 reversed the signaling by PPARγ/PTEN;the reduction in EMT-activating transcription factors,such as Snai1 and Zeb1;and the antimetastatic effect of the ApoSQ injection.Thus,the injection of apoptotic lung cancer cells may offer a new strategy for the prevention of lung metastasis.