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Biomedical subjects

Shu Zheng

Publications and source records attributed to Shu Zheng.

At least 37 records · Page 2Linked to original sources

Application of serum protein fingerprinting coupled with artificial neural network model in diagnosis of hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma tends to present at a late clinical stage with poor prognosis. Therefore, it is urgent to explore and develop a simple, rapid diagnostic method, which has high sensitivity and specificity for hepatocellular carcinoma at an early stage. In this study, the serum proteins in patients with hepatocellular carcinoma or liver cirrhosis and in normal controls were analysed. Surface enhanced laser desorption/ionization time-of-flight mass (SELDI-TOF-MS) spectrometry was used to fingerprint serum protein using the protein chip technique and explore the value of the fingerprint, coupled with artificial neural network, to diagnose hepatocellular carcinoma. METHODS: Of the 106 serum samples obtained, 52 were from patients with hepatocellular carcinoma, 22 from patients with liver cirrhosis and 32 from healthy volunteers. The samples were randomly assigned into a training group (n = 70, 35 patients with hepatocellular carcinoma, 14 with liver cirrhosis, and 21 normal controls) and a testing group (n = 36, 17 patients with hepatocellular carcinoma, 8 with liver cirrhosis, and 11 normal controls). An artificial neural network was trained on data from 70 individuals in the training group to develop an artificial neural network diagnostic model and this model was tested. The 36 sera in the testing group were analysed with blind prediction by using the same flowchart and procedure of data collection. The 36 serum protein spectra were clustered with the preset clustering method and the same mass/charge (M/Z) peak values as those in the training group. Matrix transfer was performed after data were output. Then the data were input into the previously built artificial neural network model to get the prediction value. The M/Z peaks of the samples with more than 2000 M/Z were normalized with biomarker wizard of ProteinChip Software version 3.1 for noise filtering. The first threshold for noise filtering was set at 5, and the second was set at 2. The 10% was the minimum threshold for clustering. The statistical analysis of the data of serum protein mass spectrum was performed in the groups (normal vs. hepatocellular carcinoma, and liver cirrhosis vs. hepatocellular carcinoma) with the t test. RESULTS: Comparison between the groups of hepatocellular carcinoma and normal control: The mass spectra from 56 samples (hepatocellular carcinoma and normal controls) in the training group were analysed and 241 peaks were obtained. In addition, 21 peaks from them were used for comparison between the groups of hepatocellular carcinoma and normal controls (P < 0.01). Only 2 peaks at 3015 M/Z and 5900 M/Z were selected with significant difference (P < 10 (-9)). A model was developed based on these two proteins with different M/Z. It was confirmed that this artificial neural network model can be used for comparison between the groups of hepatocellular carcinoma and normal controls. The sensitivity was 100% (17/17), and the specificity was 100% (11/11). Comparison between the groups of hepatocellular carcinoma and liver cirrhosis: The mass spectra from 49 samples in the training group (including patients with hepatocellular carcinoma and liver cirrhosis) were analysed and 208 peaks were obtained. In addition, 21 peaks from them were used for comparison between the groups of hepatocellular carcinoma and liver cirrhosis (P < 0.01). Only 2 peaks at 7759 M/Z, 13134 M/Z were selected with significant difference (P < 10 (-9)). A model was developed based on these two proteins with different M/Z. It was confirmed that this artificial neural network model can be used for comparison between the groups of hepatocellular carcinoma and liver cirrhosis. The sensitivity was 88.2% (15/17), and the specificity was 100% (8/8). CONCLUSIONS: The specific biomarkers selected with the SELDI technology could be used for early diagnosis of hepatocellular carcinoma.

Adult↗

Primate lentiviral virion infectivity factors are substrate receptors that assemble with cullin 5-E3 ligase through a HCCH motif to suppress APOBEC3G.

Cullin-Ring E3 ubiquitin ligases target substrates for ubiquitin-dependent, proteasome-mediated degradation and regulate critical cellular processes. These cullins assemble with cellular substrate receptor proteins through specific adaptor molecules. F-box- and BC-box-containing receptors use Skp1, ElonginB, and ElonginC as adaptors to recruit Cul1/Cul7 and Cul2/Cul5, respectively. At present, the determinants of Cul2 vs. Cul5 specificity for the BC-box-containing receptors are poorly defined. Here, we demonstrate that primate lentiviral Vif (virion infectivity factor) proteins represent previously uncharacterized substrate receptor proteins that contain divergent BC-box motifs. These molecules selectively assemble with a Cul5-E3 ligase to suppress the antiviral activity of autologous cytidine deaminase APOBEC3G. A previously unrecognized Hx5Cx(17-18)Cx(3-5)H motif that is highly conserved among all primate lentiviral Vif proteins was found to be critical for the selective assembly and activity of Vif-Cul5-E3 ligase. Non-primate lentiviral Vif proteins, which lack this HCCH motif, displayed reduced interaction with Cul5. These data suggest that in addition to target protein specificity, substrate receptor proteins play important roles in cullin selection and functional assembly of cullin-Ring E3 ligases. The discovery of these viral substrate receptor molecules that recruit Cul5 through distinct mechanisms from cellular proteins may facilitate the identification of additional cellular factors that regulate cellular functions through Cul5-E3 ligase. Motifs in Vif that are absent from cellular proteins could also be targets for the development of innovative therapeutics.

APOBEC-3G Deaminase↗

Overexpression of Shp2 tyrosine phosphatase is implicated in leukemogenesis in adult human leukemia.

Shp2 tyrosine phosphatase plays a critical role in hematopoiesis, and dominant active mutations have been detected in the human gene PTPN11, encoding Shp2, in child leukemia patients. We report here that although no such mutations were detected in 44 adult leukemia patients screened, Shp2 expression levels were significantly elevated in primary leukemia cells and leukemia cell lines, as compared with normal hematopoietic progenitor cells. The Shp2 protein amounts correlated well with the hyperproliferative capacity but were inversely associated with the differentiation degree of leukemia cells. Suppression of Shp2 expression induced apoptosis and inhibition of leukemic cell clonogenic growth. Notably, the majority of Shp2 was preferentially localized to the plasma membrane and was constitutively phosphorylated on tyrosine in leukemia cells, and also in normal hematopoietic cells following mitogenic stimulation. Based on these results, we propose that aberrantly increased expression of Shp2 may contribute, collaboratively with other factors, to leukemogenesis.

Adolescent↗

[Establishment of rat model of transplantation of kidney containing adrenal implants and its protective effects on the transplanted kidney].

OBJECTIVE: To establish a rat model of transplantation of kidney containing adrenal implants and to explore the protective effects of the adrenal implants on the transplanted kidney. METHODS: Fragments of adrenal cortex of the left adrenal gland were obtained and implanted into the left kidneys of the same would-be donor rats. Twenty-four Lewis rats were transplanted with the left kidneys containing adrenal gland implants of SD rats (Group I), and another Lewis rats were transplanted with the unprepared left kidneys of 24 SD rats (Group II). Seven days after the implantation the right kidneys of the recipient rats were resected. No immunosuppressant was used. The survival time was observed. Blood samples were collected at different time points to examine the serum corticosterone, creatinine, and urea nitrogen. Light microscopy was used to observe the morphology of the implanted kidneys and the adrenal implants. RESULTS: Histological examination showed that the adrenal gland implants survived well with good blood supply. Seven days after the resection of the right kidneys microscopy showed atrophy of the adrenal implants. There were no significant differences in serum corticosterone, creatinine, and urea nitrogen between the levels before and 7 days after transplantation and between the 2 groups. The survival time of Group I was 10.2 d +/- 2.2 d, significantly longer than that of Group II (7 d +/- 2 d, P < 0.05). CONCLUSION: Adrenal implants that survive and recover their endocrinal function have protective effect on the transplanted kidney in early period.

Adrenal Glands↗

Transformed immortalized gastric epithelial cells by virulence factor CagA of Helicobacter pylori through Erk mitogen-activated protein kinase pathway.

CagA of Helicobacter pylori is a protein that has been closely associated with gastric cancer and that can intervene with signal pathways in cells. Its precise relationship with the occurrence of gastric cancer, however, remains unclear. The purpose of this study is to investigate whether CagA can promote transformation of normal gastric epithelial cells and to consider via what mechanisms CagA may exert its effects. Transformed colonies were merged in soft-agarose medium after immortalized gastric epithelial cells were transfected with recombinant pLHCX retrovirus with cagA and/or dimethylhydrazine. The number of transformed colonies in the group containing cagA/pLHCX retrovirus, combined with a subthreshold dose of dimethylhydrazine, was more than that for cagA/pLHCX retrovirus or dimethylhydrazine at a subthreshold dose alone. For cagA-transfected cells, only IQGAP-2, R-Ras and B-Raf of the Ras/mitogen-activated protein kinase signal pathway were markedly increased, and the activity of extracellular signal-regulated kinase 1/2 (Erk1/2) kinase was significantly higher than that in dimethylhydrazine-transformed cells or control cells. However, no evidence of alteration of any other molecules of the Ras superfamily was observed in cagA-transfected cells. These findings suggest that CagA can transform gastric epithelial cells through activation of the Erk1/2 pathway; this mechanism may, however, be independent of Ras activation.

Cell Line↗

Transformation of immortalized colorectal crypt cells by microcystin involving constitutive activation of Akt and MAPK cascade.

It has been shown by epidemiological and animal studies that microcystin is an important exogenous factor involved in the carcinogenesis of colorectal cancer (CRC). However, details of the mechanism remain unclear. Transformation of colorectal cells is an important initial step in carcinogenesis. Whether microcystin is capable of transforming immortalized colorectal crypt cells, and what the mechanism might be, was investigated. In the present study, we demonstrated that immortalized colorectal crypt cells could be transformed by microcystin. Transformed colorectal crypt cells showed an anchorage-independent growth phenotype, and the proliferation activities of microcystin-transformed cells were also greater than that of immortalized colorectal crypt cells. The Akt and the p38, JNK of mitogen-activated protein kinase (MAPK) pathways in microcystin-transformed cells were found to be constitutively activated. In microcystin-transformed cells, PI3K, MAPKAPK2, Akt, cyclin D1 and cyclin D3 in the Akt pathway; IQGAP-2, RabGTPase, Rap1GAP, RasGAP, R-Ras, Krev-1 and TC21 of the Ras GTP/GDP protein family; and A-Raf, B-Raf and PAK in the Ras/MAPK pathway were all markedly upregulated. However, in positive control cells, dimethylhydrazine-transformed cells, only the Akt pathway was activated by PI3K, and no evidence of alteration of any molecules of the Ras superfamily was observed. Inhibition of Akt, p38 and JNK activation led to a reduced proliferation of microcystin-transformed cells. This implies that the constitutive activation of Akt and the p38, JNK of MAPK pathways in microcystin-transformed cells may be the mechanism by which this important external factor acts in the carcinogenesis of CRC.

Cell Culture Techniques↗

[Mutation detection of mismatch repair genes in hereditary nonpolyposis colorectal cancer by denaturing high-performance liquid chromatography].

OBJECTIVES: To establish DHPLC method in detecting mutations of mismatch repair genes, hMLH1 and hMSH2, and to identify germline mutations of hMLH1 and hMSH2 in HNPCC kindreds fulfilling Chinese HNPCC criteria. METHODS: Fourteen peripheral blood DNA samples from 14 unrelated HNPCC probands fulfilling Chinese HNPCC criteria were obtained respectively. PCR amplified 35 exons of two main mismatch repair genes, hMLH1 and hMSH2. DHPLC followed by DNA sequencing was used to detect and confirm mutations. RESULTS: a total of 41 colorectal cancers and 19 extracolonic tumors were developed in 14 HNPCC kindreds, and gastric cancer was the most common extracolonic tumor type. Twelve single nucleotide changes were identified by DHPLC in 14 probands. Among them, three were missense mutations, one was a nonsense mutation. Other single nucleotide changes included five single nucleotide polymorphisms, two intron single nucleotide changes, one synonymous mutation. hMLH1 EXON19 CODON749 TAC-->TAG (Tyr-->X), hMSH2 EXON12 CODON629 CAA-->CGA (Gln-->Arg) and hMSH2 EXON15 CODON839 CAT-->CGT (His-->Arg) were new discovered mutations. CONCLUSIONS: (1) DHPLC was considered to be highly effective, convenient technique with consistent results for the mutation detection of hMLH1 and hMSH2 genes. (2) Valid mutations of hMLH1 and hMSH2 genes were identified in about one-third HNPCC kindreds fulfilling Chinese HNPCC criteria and missense mutation was the most common mutational types in this cohort of families.

Adaptor Proteins, Signal Transducing↗

Characterization of CagA variable region of Helicobacter pylori isolates from Chinese patients.

AIM: To characterize the CagA variable region of Helicobacter pylori isolates from Chinese patients. METHODS: DNA fragments in CagA variable region were amplified and sequenced respectively from genomic DNA of 19 isolates from patients with gastric cancer and 20 isolates from patients with chronic gastritis. The tendency of phosphorylation in tyrosine(s) of CagA proteins was evaluated subsequently by phosphorylation assay in vivo and in vitro respectively. RESULTS: About 97.44% (38/39) H pylori isolates possessed CagA gene. CagA(+) strains contained 2-4 tandem five-amino-acid motifs EPIYA but only one EPIYA had repeated sequence in CagA variable region in different isolates. There was no significant difference between the number of EPIYA motifs in H pylori from patients with different diseases. However, only tyrosine site in EPIYA within repeated sequence could be phosphorylated by AGS cells in vivo although all tyrosine sites in EPIYA could be phosphorylated in vitro. CONCLUSION: CagA in Chinese has no functional difference in perturbing cellular signal pathway among different H pylori isolates.

Adult↗

Expression of ST13 in colorectal cancer and adjacent normal tissues.

AIM: To investigate the in situ expression of suppression of tumorigenecity 13 (ST13) mRNA in both colorectal cancer and adjacent normal tissues. METHODS: Colorectal cancer cell lines SW1116, SW620 and CoLo205 were enrolled to confirm the feasibility of the in situ hybridization procedure. Seven colorectal cancer and adjacent normal tissues were included for RNA-RNA in situ hybridization. RESULTS: The expression of ST13 in the seven normal colon tissues was positive and the positive signals appeared in mucosal cells. Only three of the seven colorectal cancer tissues had positive hybridization signals that appeared in adenocarcinoma cells. CONCLUSION: The expression of ST13 decreases in colorectal cancer tissue compared with that in adjacent normal tissue. ST13 is mostly expressed in colorectal epithelia and adenocarcinoma cells.

Adenocarcinoma↗

[Using ANN and serum protein pattern models in liver cancer diagnosis].

OBJECTIVE: To set up a method for the detection of the serum protein fingerprint pattern by using the protein chip technology for exploration of serum protein fingerprint pattern models based on the artificial neural network in diagnosis of liver cancer. METHODS: One hundred and six serum samples form subjects with liver cancer, hepatocirrhosis, and healthy individuals were detected with protein biochip surface enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS) for protein fingerprint pattern, and analyzed with the artificial neural network. The 106 samples were randomly put into a training group (n = 70, 35 patients with liver cancer, 14 patients with hepatocirrhosis, and 21 healthy individuals) and a blind test group (n = 36, 17 patients with liver cancer, 8 patients with hepatocirrhosis, and 11 healthy individuals). RESULTS: The serum protein fingerprint pattern model obtained by the artificial neural network from training group was used to detect the 36 unknown serum samples. The sensitivity and specificity of this method in detection of liver cancer were 88.2% (15/17) and 94.6% (18/19) respectively. CONCLUSION: In comparison with the traditional methods, this new method has higher sensitivity and specificity in diagnosis of liver cancer and should be further studied.

Adult↗

Alcohol drinking and colorectal cancer: a population-based prospective cohort study in China.

STUDY OBJECTIVE: To asses the association between alcohol consumption and the risk of colorectal cancer (CRC) in the Chinese population. DESIGN: A population-based prospective cohort study was initiated from the colorectal cancer screening population in Jiashan County in 1989-1990. The drinking habits of individuals were investigated with demographic information. SETTING: A cohort study was followed-up from 1st May 1990 to 1st January 2001 and censored at the date of diagnosis of CRC, at death from any causes, or at 1st January 2001, whichever came first, and the person-time was computed. PARTICIPANTS: Two hundred and forty two CRC patients were diagnosed during the study period and 64,100 individuals finished the follow-up. RESULTS: The distribution of sex, smoking status, occupation, education level and marital status were all significantly different among different drinking habits at baseline. When the above factors were adjusted, no significant association was observed between alcohol consumption and the risk of CRC. Exclusion of individuals diagnosed cancer less than 1 year after the examination date did not alter the strength of an alcohol-CRC relationship. Further analysis in sex strata also did not show a significant relationship. CONCLUSIONS: Alcohol drinking may not be associated with a higher risk of CRC in the Chinese population.

Adult↗

SELDI-TOF-MS: the proteomics and bioinformatics approaches in the diagnosis of breast cancer.

Breast cancer has never had any good serum tumor markers. Therefore, we developed and evaluated a proteomics approach to searching for new biomarkers and building diagnostic models. SELDI-TOF-MS ProteinChip was used to detect the serum protein patterns of 49 breast cancer patients, 51 patients with benign breast diseases, and 33 healthy women. The diagnostic models were developed and validated using bioinformatics tools such as artificial neural networks and discriminant analysis. In total, four models were built and their sensitivities and specificities were satisfactory. The abilities of these models to diagnose stage I breast cancer were not worse than for stages II-IV (P>0.05). Four candidate biomarkers of breast cancer were found. The high sensitivity and specificity achieved by this method show great potential for the early detection of breast cancer and facilitation of discovering new and improved biomarkers.

Adult↗

Serum protein fingerprinting coupled with artificial neural network distinguishes glioma from healthy population or brain benign tumor.

To screen and evaluate protein biomarkers for the detection of gliomas (Astrocytoma grade I-IV) from healthy individuals and gliomas from brain benign tumors by using surface enhanced laser desorption/ionization time of flight mass spectrometry (SELDI-TOF-MS) coupled with an artificial neural network (ANN) algorithm. SELDI-TOF-MS protein fingerprinting of serum from 105 brain tumor patients and healthy individuals, included 28 patients with glioma (Astrocytoma I-IV), 37 patients with brain benign tumor, and 40 age-matched healthy individuals. Two thirds of the total samples of every compared pair as training set were used to set up discriminating patterns, and one third of total samples of every compared pair as test set were used to cross-validate; simultaneously, discriminate-cluster analysis derived SPSS 10.0 software was used to compare Astrocytoma grade I-II with grade III-IV ones. An accuracy of 95.7%, sensitivity of 88.9%, specificity of 100%, positive predictive value of 90% and negative predictive value of 100% were obtained in a blinded test set comparing gliomas patients with healthy individuals; an accuracy of 86.4%, sensitivity of 88.9%, specificity of 84.6%, positive predictive value of 90% and negative predictive value of 85.7% were obtained when patient's gliomas was compared with benign brain tumor. Total accuracy of 85.7%, accuracy of grade I-II Astrocytoma was 86.7%, accuracy of III-IV Astrocytoma was 84.6% were obtained when grade I-II Astrocytoma was compared with grade III-IV ones (discriminant analysis). SELDI-TOF-MS combined with bioinformatics tools, could greatly facilitate the discovery of better biomarkers. The high sensitivity and specificity achieved by the use of selected biomarkers showed great potential application for the discrimination of gliomas patients from healthy individuals and gliomas from brain benign tumors.

Adult↗

An integrated approach utilizing proteomics and bioinformatics to detect ovarian cancer.

OBJECTIVE: To find new potential biomarkers and establish the patterns for the detection of ovarian cancer. METHODS: Sixty one serum samples including 32 ovarian cancer patients and 29 healthy people were detected by surface-enhanced laser desorption/ionization mass spectrometry (SELDI-MS). The protein fingerprint data were analyzed by bioinformatics tools. Ten folds cross-validation support vector machine (SVM) was used to establish the diagnostic pattern. RESULTS: Five potential biomarkers were found (2085 Da, 5881 Da, 7564 Da, 9422 Da, 6044 Da), combined with which the diagnostic pattern separated the ovarian cancer from the healthy samples with a sensitivity of 96.7%, a specificity of 96.7% and a positive predictive value of 96.7%. CONCLUSIONS: The combination of SELDI with bioinformatics tools could find new biomarkers and establish patterns with high sensitivity and specificity for the detection of ovarian cancer.

Adolescent↗

Combination of small interfering RNAs mediates greater inhibition of human hepatitis B virus replication and antigen expression.

OBJECTIVES: To evaluate the inhibitory effect mediated by combination of small interfering RNAs (siRNAs) targeting different sites of hepatitis B virus (HBV) transcripts on the viral replication and antigen expression in vitro. METHODS: (1) Seven siRNAs targeting surface (S), polymerase (P) or precore (PreC) region of HBV genome were designed and chemically synthesized. (2) HBV-producing HepG2.2.15 cells were treated with or without siRNAs for 72 h. (3) HBsAg and HBeAg in the cell culture medium were detected by enzyme-linked immunoadsorbent assay. (4) Intracellular viral DNA was quantified by real-time PCR (Polymerase Chain Reaction). (5) HBV viral mRNA was reverse transcribed and quantified by real-time PCR. (6) The change of cell cycle and apoptosis was determined by flow cytometry. RESULTS: Our data demonstrated that synthetic small interfering RNAs (siRNAs) targeting S and PreC gene could efficiently and specifically inhibit HBV replication and antigen expression. The expression of HBsAg and HBeAg and the replication of HBV could be specifically inhibited in a dose-dependent manner by siRNAs. Furthermore, our results showed that the combination of siRNAs targeting various regions could inhibit HBV replication and antigen expression in a more efficient way than the use of single siRNA at the same final concentration. No apoptotic change was observed in the cell after siRNA treatment. CONCLUSION: Our results demonstrated that siRNAs exerted robust and specific inhibition on HBV replication and antigen expression in a cell culture system and combination of siRNAs targeting different regions exhibited more potency.

Apoptosis↗

Influence of CO2 pneumoperitoneum on intracellular pH and signal transduction in cancer cells.

OBJECT: The authors studied the influence of CO(2) pneumoperitoneum on intracellular pH and signal transduction arising from cancer cell multiplication in laparoscopic tumor operation. METHOD: They set up a simulation of pneumoperitoneum under different CO(2) pressure, and then measured the variation of intracellular pH (pHi) at different time and the activity of protein kinase C (PKC) and protein phosphatase 2a (PP2a) at the end of the pneumoperitoneum. After 1 week, the concentration of cancer cells in the culture medium was calculated. RESULT: When the pressure of CO(2) pneumoperitoneum was 0, 10, 20, 30 mmHg respectively, the average pHi was 7.273, 7.075, 6.783, 6.693 at the end of the pneumoperitoneum; PKC activity was 159.4, 168.5, 178.0, 181.6 nmol/(g.min) and PP2a was 4158.3, 4066.9, 3984.0, 3878.5 nmol/(g.min) respectively. After 1 week, the cancer cells concentration was 2.15 x 10(5), 2.03 x 10(5), 2.20 x 10(5), 2.18 x 10(5) L(-1). CONCLUSION: CO(2) pneumoperitoneum could promote acidosis in cancer cells, inducing the activation of protein kinase C and deactivation of protein phosphatase 2a, but it could not accelerate the mitosis rate of the cancer cells.

Animals↗

Screening the active constituents of Chinese medicinal herbs as potent inhibitors of Cdc25 tyrosine phosphatase, an activator of the mitosis-inducing p34cdc2 kinase.

OBJECTIVE: To screen and evaluate the active constituents of Chinese medicinal herbs as potent inhibitors of Cdc25 phosphatase. METHODS: The affinity chromatography purified glutashione-S-transferase/Cdc25A phosphatase fusion protein and Cdc2/cyclin B from the extracts of starfish M phase oocytes are used as the cell cycle-specific targets for screening the antimitotic constituents. We tested 9 extracts isolated from the Chinese medicinal herbs and vegetables including the agents currently used in cancer treatment by measuring the inhibition of Cdc25A phosphatase and Cdc2 kinase activity. The antitumor activity of the extracts was also evaluated by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and flow cytometry. RESULTS: Cdc25A inhibitory activity and antitumor activity are detected in the extracts isolated from three Chinese medicinal herbs Agrimona pilosa; Herba solani lyrati; Galla chinesis. CONCLUSION: We found three extracts isolated from Chinese medicinal herbs have potential inhibitory activity of Cdc25 phosphatase using a highly specific mechanism-based screen assay for antimitotic drug discovery.

Apoptosis↗