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Acute pancreatitis (AP) is a prevalent gastrointestinal disorder. The immune response plays a crucial role in AP progression. However, the impact of immune regulatory checkpoint PD-L1 on severe acute pancreatitis (SAP) remains uncertain. Hence, this study aimed to examine the influence of PD-L1 on SAP. We assessed PD-L1 expression in neutrophils and monocytes obtained from SAP patients. We induced SAP in C57BL/6J mice, PD-L1 gene-deficient mice, and PD-L1 humanized mice using intraperitoneal injections of cerulein plus lipopolysaccharide. Prior to the initial cerulein injection, a PD-L1 inhibitor was administered. Pancreatic tissues were collected for morphological and immunohistochemical evaluation, and serum levels of amylase, lipase, and cytokines were measured. Flow cytometry analysis was performed using peripheral blood cells. The expression of PD-L1 in neutrophils and monocytes was significantly higher in SAP patients compared to healthy individuals. Likewise, the expression of PD-L1 in inflammatory cells in the peripheral blood of SAP-induced C57BL/6J mice was notably higher than in the control group. In mice with PD-L1 deficiency, SAP model exhibited lower pancreatic pathology scores, amylase, lipase, and cytokine levels compared to wild-type mice. PD-L1 deletion resulted in reduced neutrophil apoptosis, leading to an earlier peak in neutrophil apoptosis. Furthermore, it decreased early monocyte apoptosis and diminished the peak of T lymphocyte apoptosis. Within the SAP model, administration of a PD-L1 inhibitor reduced pancreatic pathology scores, amylase, lipase, and cytokine levels in both C57BL/6J mice and PD-L1 humanized mice. These findings suggest that inhibiting PD-L1 expression can alleviate the severity of SAP., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Our previous study found that the combination of halofuginone (HF) and artemisinin (ATS) synergistically arrest colorectal cancer (CRC) cells at the G1/G0 phase of the cell cycle; however, it remains unclear whether HF-ATS induces cell death. Here we report that HF-ATS synergistically induced caspase-dependent apoptosis in CRC cells. Specifically, both in vitro and in vivo experiments showed that HF or HF-ATS induces apoptosis via activation of caspase-9 and caspase-8 while only caspase-9 is involved in ATS-induced apoptosis. Furthermore, we found HF or HF-ATS induces autophagy; ATS can't induce autophagy until caspase-9 is blocked. Further analyzing the crosstalk between autophagic and caspase activation in CRC cells, we found autophagy is essential for activation of caspase-8, and ATS switches to activate capase-8 via induction of autophagy when caspase-9 is inhibited. When apoptosis is totally blocked, HF-ATS switches to induce autophagic cell death. This scenario was then confirmed in studies of chemoresistance CRC cells with defective apoptosis. Our results indicate that HF-ATS induces cell death via interaction between apoptosis and autophagy in CRC cells. These results highlight the value of continued investigation into the potential use of this combination in cancer therapy., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

Hepatocyte apoptosis is a crucial factor affecting liver quality in brain-dead donors. The identification of key molecular proteins involved in brain-death (BD)-induced hepatocyte apoptosis may help determine an effective method for improving the quality of livers from brain-dead donors. In this study, we used in vivo and in vitro models to investigate the role of chitinase-3-like protein 1 (CHI3L1) in promoting liver cell apoptosis after BD. Chitin was used to inhibit CHI3L1 in a rat model of BD. Macrophage polarization of THP-1 cells and hypoxia/reoxygenation (H/R) of LO-2 cells were used to mimic BD-induced cell stress in liver. We found that CHI3L1 played a vital role in promoting liver cell apoptosis. Six hours after BD, CHI3L1 expression was significantly upregulated in liver macrophages and was associated with BD-induced M1 polarization of these cells. In liver cells cultured under H/R conditions, recombinant CHI3L1 activated the protease-activated receptor 2 (PAR2)/c-June N-terminal kinase (JNK) apoptotic pathway and aggravated apoptosis. Compared with the control group, chitin particles inhibited the expression of CHI3L1 in the liver of brain dead rats, thereby reducing activation of the hepatocyte surface receptor, PAR2, and its downstream JNK/caspase-3 signaling pathway, ultimately reducing hepatocyte apoptosis. In conclusion, our results indicate that CHI3L1 relies on a PAR2/JNK-mediated mechanism to promote BD-induced hepatocyte apoptosis., Competing Interests: Declaration of competing interest All authors have no conflicts of interest to disclose., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Bcl-2 family members play an important role in the development of malignant lymphoma and can induce drug resistance in anticancer treatment. The development of small molecules targeting Bcl-2 family proteins may be a new strategy for the treatment of malignant lymphoma. In this study, we investigate the antitumor effect and cellular mechanism of a novel Bcl-2/Bcl-xL dual inhibitor, BM-1197, in DCBCL and Burkitt lymphoma cells., Methods: The CCK-8 assay was used to detect cell viability. Apoptosis was determined by Hoechst 33258 staining and flow cytometry. The activity of caspase-3/caspase-9 was determined using a caspase-3/caspase-9 activity kit. Western blotting analysis was performed to evaluate the changes in protein expression. Functional analysis was performed via immunoprecipitation and siRNA interference. Human malignant lymphoma xenograft models in nude mice were established for in vivo efficacy detection., Results: We find that BM-1197 exerts potent growth-inhibitory activity against lymphoma cells that harbor high expression of Bcl-2 and Bcl-xL in vitro and has a synergistic effect with chemotherapeutic drugs. Mechanistically, we see that the intrinsic apoptosis pathway is activated upon BM-1197 treatment. BM-1197 affects the protein interactions of Bak/Bcl-xl, Bim/Bcl-2, Bim/Bcl-xl, and PUMA/Bcl-2 and induces conformational changes in the Bax protein, which result in the activation of Bax and release of cytochrome c, activate caspase - 9, - 3, and - 7 and finally induce cell apoptosis. Furthermore, our data demonstrate that BM-1197 exhibits strong anti-tumor effects against established human malignant lymphoma xenograft models., Conclusions: Our study demonstrated BM-1197 exerts potent antitumor effects both in vitro and in vivo and provides promising preclinical data for the further development of BM-1197 in malignant lymphoma.

To investigate the effects of gossypol acetate on apoptosis in primary cultured cells from patients with acute lymphoblastic leukemia (ALL) and chronic lymphocytic leukemia (CLL) and its synergistic effect with dexamethasone. The apoptosis-inducing effect of gossypol acetate on primary cultured leukemia cells was analyzed by flow cytometry (FCM). The effect of gossypol acetate on survival rates of Raji cells and mononuclear cells (MNC) from normal bone marrow were evaluated by MTT assay. After co-treatment with gossypol acetate and dexamethasone, the apoptosis rate of Raji cells was detected by FCM. The results showed that gossypol acetate was able to induce apoptosis in primary cultured ALL cells at concentrations of ≥ 5 µmol/L. The effect was concentration and time dependent. Apoptosis-inducing concentration in CLL cells was higher than that in ALL cells. After exposing to 50 µmol/L gossypol acetate for 48 h, the apoptosis rate of ALL and CLL cells were (90.4 ± 6.2)% and (51.7 ± 10.3)% separately. No major growth inhibitory effect was observed in MNC from normal bone marrow when they were exposed to gossypol acetate at concentrations lower than 10 µmol/L. After exposing for 48 and 72 h, the IC(50) of gossypol acetate for MNC from normal bone marrow was 7.1 and 9.1 times as much as the IC(50) of Raji cells. Co-treatment with 10 µmol/L gossypol acetate and dexamethasone remarkably increased the apoptosis rate of Raji cells. It is concluded that the gossypol acetate has apoptosis-inducing activity in primary cultured leukemia cells from patients diagnosed as ALL and CLL in vitro. The inhibitory effect of gossypol acetate on MNC from normal bone marrow is less prominent than that on Raji cells. Co-treatment with gossypol acetate and dexamethasone notably amplified the pro-apoptosis activity of the latter in Raji cells.

Objective: To investigate the effect of water extracts of Coptidis Rhizoma and Evodiae Fructus (CREF) on the proliferation and apoptosis of human gastric carcinoma cells (SGC-7901) and determine the optimal proportion of Coptidis rhizoma to Evodiae fructus., Methods: The growth inhibition of SGC-7901 cells treated with the water extracts of CREF of varying proportions was tested with MTT assay. The cell apoptotic rate and mitochondrial membrane potential were analyzed with flow cytometry., Results: The water extract of CREF with Coptidis Rhizoma: Evodiae Fructus proportions at 1:6, 2:5, 3:4, 4:3, 5:2, and 6:1 all significantly inhibited the growth of SGC-7901 cells after a 24-h or 48-h treatment (P<0.05). The growth inhibition and cell death ratio both exhibited a dose-dependent pattern of Coptidis Rhizoma. Flow cytometry analysis showed that, after treatment of the cells with CREF at the proportions of 1:6, 2:5, 3:4, 4:3, 5:2, and 6:1, the apoptotic rate were (8.50 ∓ 1.59)%, (9.90 ∓ 1.01)%, (17.15∓1.68)%, (21.55 ∓ 1.97)%, (34.10 ∓ 1.06)% and (34.40 ∓ 1.02)%, respectively, all significantly higher than that in the control group [(1.69 ∓ 1.91)%, P<0.05]. JC-1 Kit staining showed that mitochondrial membrane potential of SGC-7901 cells was decreased and the ratio of green to red fluorescence increased significantly after incubation with CREF., Conclusion: CREF can inhibit the growth and induce apoptosis of SGC-7901 cells, and the strongest effect is achieved at the optimal proportion of Coptidis Rhizoma and Evodiae Fructus at 6:1.

Background: To assess the effects of Glycine tomentella Hayata (GTH), a traditional herbal medicine for treatment of rheumatic diseases on the expression of the proinflammatory cytokines and on the clearance of apoptotic cells by macrophages., Methods: RAW264.7 cells were cultured with lipopolysaccharide (LPS) in the presence or absence of ethanol extract of GTH. The expression of proinflammatory cytokines IL-1β, IL-6, and TNF-α, and inducible nitric oxide synthase (iNOS) and transglutaminase 2 (TG2) were assayed by reverse transcriptase-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). Matrix metalloproteinase (MMP)-2 and MMP-9 were assayed by gelatin zymography. For detecting uptake of apoptotic cells, RAW264.7 cells were cultured with carboxyfluorescein diacetate (CFDA)-stained apoptotic cells and assayed by flow cytometry., Results: The major components of GTH analyzed by high-performance liquid chromatography (HPLC) chromatogram were daidzein (42.5%), epicatechin (28.8%), and naringin (9.4%).GTH treatment inhibited the expression of proinflammatory cytokines IL-1β, IL-6 and MMP-9 but did not affect the expression of TNF-α and iNOS. GTH significantly enhanced the expression of TG2 and the clearance of apoptotic cells by RAW264.7 macrophages., Conclusions: GTH inhibits proinflammatory cytokine secretion and MMP-9 activity, enhances apoptotic cell uptake and up-regulates TG2 expression. Our data show that GTH might have beneficial effects on rheumatic diseases.

Objective: To investigate the effects of gossypol acetate on proliferation and apoptosis in Raji lymphoblastoid cells and explore the possible mechanism., Methods: Trypan blue staining and ethyl thiazolyl diphenyl-tetrazolium bromide (MTT) assay were performed to measure the effect of gossypol acetate on the growth of Raji cells. The morphologic changes were observed with Wright's staining assay. Apoptosis was identified by agarose-gel electrophoresis and annexin V-FITC marked flow cytometry (FCM) analysis. The distribution of cell cycle, apoptosis rate, and Bcl-2 protein expression were analyzed by FCM. Caspase-3 activity was detected by colorimetric assay., Results: Gossypol acetate inhibited proliferation and induced apoptosis of Raji cells at concentration higher than 5 micromol/L. The effects were both dose- and time- dependent. Cycle analysis indicated the alteration of cell cycle and G0/G1 arrest. The activation of Caspase-3 was observed by colorimetric assay. The results of flow cytometry showed that the down-regulation of Bcl-2 protein expression and the activation of Caspase-3 seemed to occur simultaneously., Conclusion: Gossypol acetate can inhibit the growth of Raji cells and induce their apoptosis. The mechanism may be related to the alteration of cell cycle and the down-regulation of Bcl-2 protein expression.

This study was aimed to investigate the effects of apogossypolone (ApoG2) on proliferative inhibition and apoptotic induction of multiple myeloma cells and its mechanism. The effects of ApopG2 on cell growth, cell viability, cell cycle and cell apoptosis were determined by Hoechst 33258 staining, DNA ladder formation and subdiploid peak analysis respectively. Cleavage of caspase-3 and caspase-9 was analyzed by colorimetric assay. Expression of BCL-2 and BCL-XL was detected by flow cytometry. The results indicated that the ApoG2 inhibited multiple myeloma cell proliferation in dose-and time-dependent manners, with IC(50) value to both U266 and Wusl cells at 0.1 and 0.2 micromol/L at 48 hours after treatment. ApoG2 effectively inhibited the proliferation of multiple myeloma cells, the IC(50) value in U266 cells and Wusl cells (at 48 hours) were 0.1 micromol/L and 0.2 micromol/L respectively. ApoG2 could induce the apoptosis of cells of myeloma in a time-dependent manner.The typical apoptotic morphological changes were observed under transmission electron microscope, while DNA ladder formation and remarkable peak of subdiploid cells appeared. ApoG2 could arrest the myeloma cells in G(2) phase, increasing from 9.7%(0 micromol/L) to 19.6% (10 micromol/L) in U266 cells and 9.8%(0 micromol/L) to 31.7% (10 micromol/L) in Wusl cells. ApoG2 could induce increase of caspase 9 and caspase 3 activity and down-regulate the expression of BCL-XL in U266 and Wusl cells, as well as the expression of BCL-2 in Wusl cells. It is concluded that ApoG2 has significant effect of antiproliferation and induction of apoptosis on multiple myeloma cells in vitro, ant its mechanisms may involve in down-regulation of BCL-2/BCL-XL and in change of cell cycle.

Aim: To investigate the in vitro and in vivo activities and related mechanism of apogossypolone (ApoG2) alone or in combination with adriamycin (ADM) against human hepatocellular carcinoma (HCC)., Methods: The IC50 of ApoG2 in vitro was tested by WST assay, and the synergistic effect was analyzed using the CalcuSyn method. Cell apoptosis was determined using 4',6-diamidino-2- phenylindole staining and flow cytometric analysis. Western blotting was used to determine the expression of apoptosis-related proteins. In vivo activity was evaluated in the xenograft model in nude mice, and apoptosis in tumor tissues was determined by terminal deoxynucleotidyl transferase-mediated digoxigenin-dUTP nick-end labeling (TUNEL) assay., Results: The IC50 of ApoG2 in HCC cells was 17.28-30.63 micromol/L. When ApoG2 was combined with ADM, increased cytotoxicity and apoptosis were observed in SMMC-7721 cells compared to treatment with ApoG2 alone. The Western blotting results indicated that the ApoG2 induced apoptosis in SMMC-7721 cells by downregulating anti-apoptotic proteins Bcl-2, Mcl-1, and Bcl-XL, up-regulating pro-apoptotic protein Noxa, and promoting the activities of caspases-9 and -3. The tumor growth of xenograft SMMC-7721 was inhibited in nude mice when ApoG2 was administered orally without causing damage to the normal tissues. The in vivo study also indicated an increasing anti-tumoral effect when ApoG2 at 100 or 200 mg/kg dosages were used together with ADM at 5.5 mg/kg, with relative tumor proliferation rate (T/C) values of 0.456 and 0.323, respectively. Apoptosis induced in vivo by ApoG2 alone or combined with ADM was confirmed by TUNEL assay in tumor tissues., Conclusion: ApoG2 is a potential non-toxic target agent that induces apoptosis by upregulating Noxa, while inhibiting anti-apoptotic proteins and promoting the effect of chemotherapy agent ADM in HCC.

Weisiensin B, a new ent-kaurane diterpenoid, was isolated from traditional Chinese herb Rabdosia weisiensis C.Y. Wu. In this study, cytotoxicity of weisiensin B was tested on four different tumor cell lines and the effect of growth inhibition and apoptosis in BEL-7402 cell line were investigated in vitro. The results indicated that weisiensin B had significant antiproliferation activity on the four cell lines. Further study on BEL-7402 cells involving Hoechst 33258 stain and DNA fragmentation assay revealed the characteristic apoptotic features of nuclear and DNA ladder formation. Flow cytometric (FCM) analysis with propidium iodide (PI) staining demonstrated that BEL-7402 cells treated with weisiensin B were arrested in G(2)/M phase. The results demonstrated that a significant fraction of weisiensin B-treated cells died by an apoptotic pathway in BEL-7402 cells.

Lymphoma is one of the most common types of hematological malignancies and proteins from the Bcl-2 family are highly expressed in human lymphomas. Apogossypolone (ApoG2), the most potent gossypol derivative, has been classified as a novel small-molecule inhibitor of antiapoptotic Bcl-2 family proteins. Here, we assessed the in-vitro cytotoxicity of ApoG2 on human U937 lymphoma cells, and explored the underlying intracellular molecular mechanisms of ApoG2. Using the WST-8 assay, we found that ApoG2 inhibited growth of U937 cells in a dose-dependent and time-dependent manner, and the IC50 values were 30.08, 14.81, and 9.26 mumol/l for 24, 48, and 72 h treatments, respectively. ApoG2 also induced apoptosis in U937 cells, as noted through changes in morphological characteristics, including cellular internucleosomal DNA fragmentation and the appearance of a sub-G1 apoptotic peak. Treatment with ApoG2 downregulated Bcl-xL and Mcl-1 protein expression and blocked the binding of Bcl-2 with Bax protein. Furthermore, ApoG2 led to an abundant release of cytochrome c from mitochondria and a five-fold increase in the activity of caspase-3 and caspase-9. Taken together, our results suggest that ApoG2 could effectively suppress the growth of human lymphoma cell line U937 through the inhibition of the antiapoptotic Bcl-2 family proteins and the induction of mitochondria-dependent apoptotic cell death.

Purpose: Polysaccharides such as chondroitin play a potent role in tumor growth, tissue repair and angiogenesis. These properties make chondroitin a good candidate for novel drug delivery systems. Diammine dicarboxylic acid platinum (DDAP), a novel polymeric platinum compound, was developed by conjugating the platinum analogue to aspartate-chondroitin for drug delivery to tumor cells. DDAP improves platinum solubility which may reduce systemic toxicity and be more efficacious than cisplatin in killing tumor cells., Methods: We tested and compared the cytotoxic effects of DDAP and CDDP on the platinum-sensitive 2008 and A2780 ovarian cancer cell lines and their platinum-resistant sublines 2008.C13 and A2780cis; we also investigated DDAP's mechanism of action., Results: In the platinum-sensitive cell lines, the cytotoxic effects of DDAP and CDDP were comparable. However, in the platinum-resistant sublines, significantly greater cell-growth inhibition was induced by DDAP than by CDDP, especially at lower doses. DDAP also induced more apoptosis than CDDP did in the 2008.C13 subline, which was partially mediated by the caspase 3-dependent pathway. In addition, lower (but not higher) doses of DDAP arrested 90% of S-phase 2008.C13 cells, which might be associated with up-regulation of p21 and maintenance of low cyclin A expression. Furthermore, greater cellular uptake of DDAP was seen in platinum-resistant than in platinum-sensitive ovarian cancer cells., Conclusions: Low-dose DDAP enhances drug delivery to platinum-resistant ovarian cancer cells and substantially inhibits their growth by inducting apoptosis and arresting cells in the S-phase, suggesting that DDAP may overcome platinum resistance in ovarian cancer.

Background: Early detection of cellular events is important to predict the outcome of the patients. This study was aimed to use (99m)Tc EC-annexin V to image tumor cells undergoing apoptosis., Methods: In 10 patients with breast cancer, scintigraphic images and dosimetric estimates were obtained after administering (99m)Tc EC-annexin V., Results: Nine of the 10 cases showed detectable (99m)Tc EC-annexin V uptake in tumor. Higher values of T/N ratios are associated with patient after treatment., Conclusions: Apoptosis can be quantified using (99m)Tc EC-annexin V.

Objective: To study the neuroprotective effect of water extracts of American Ginseng (WEAG) on Abeta25-35-induced SH-SY5Y cells apoptosis in Alzheimer's Disease cellular model., Methods: The optimal concentration and treating time of Abeta25-35 for Alzheimer's Disease cellular model as well as those of WEAG were measured by flow cytometer. In addition, the cell viability was measured by MTT test and the morphology of SH-SY5Y cells was observed by Hoechst 33258 staining., Results: Treated by Abeta25-35 50 micromol/L 72 h later, SH-SY5Y cells turned rounder, aggregated and were positively stained with fluorochrome Hoechst 33258. Cells displayed a typical sub-diploid peak in flow cytometry, and the percentage of apoptosis reaches (37.30 +/- 0.69)% (P < 0.05 as compared with the control group) (1.56 +/- 0.80)%. When incubated with Abeta 50 micromol/L and different doses (0.5, 1, 5 mg/ml) of WEAG for 72h, the characteristics of apoptosis as measured by FCM dose-dependently declined to (16.71 +/- 1.08)%, (10.52 +/- 2.11)% and (3.39 +/- 1.65)%, respectively (P < 0.05 as compared with the model group)., Conclusion: Water extracts of American Ginseng have markedly neuroprotective effects on SH-SY5Y cells apoptosis induced by Abeta25-35.

LIGHT [homologous to lymphotoxins, shows inducible expression, and competes with herpes simplex virus glycoprotein D for herpes virus entry mediator (HVEM/TR2)] is a new member of TNF superfamily. The HT-29 colon cancer cell line is the most sensitive to LIGHT-induced, IFNg-mediated apoptosis among the cell lines we have examined so far. Besides downregulation of Bcl-XL, upregulation of Bak, and activation of both PARP [poly (ADP-ribose) polymerase] and DFF45 (DNA fragmentation factor), LIGHT-induced, IFNg-mediated apoptosis of HT-29 cells involves extensive caspase activation. Caspase-8 and caspase-9 activation, as shown by their cleavages appeared as early as 24 h after treatment, whereas caspase-3 and caspase-7 activation, as shown by their cleavages occurred after 72 h of LIGHT treatment. Caspase-3 inhibitor Z-DEVD-FMK (benzyloxycarbonyl-Asp-Glu-Val-Asp-fluoromethylketone) and a broad range caspase inhibitor Z-VAD-FMK (benzyloxycarbonyl-Val-Ala-Asp fluoromethylketone) were able to block LIGHT-induced, IFNg-mediated apoptosis of HT-29 cells. The activity of caspase-3, which is one of the major executioner caspases, was found to be inhibited by both Z-DEVD-MFK and Z-VAD-FMK. These results suggest that LIGHT-induced, IFNg-mediated apoptosis of HT-29 cells is caspase-dependent, and LIGHT signaling is mediated through both death receptor and mitochondria pathways.

Background and Objective: The immunotoxin of HEL-PE38KDEL has been proven to be a novel biological reagent which has specific cytotoxic effect against breast cancer cells with positive erbB-2, 3, 4. However it has not been tested the interaction of the immunotoxin and the conventional chemical anti-cancer drugs. This study was designed to investigate the mechanism of the synergistic effect between HEL beta 1-PE38KDEL and cisplatin., Methods: The tests of Annexin V binding and Western blot were performed to detect the apoptosis in the breast cancer cell lines MDA-MB-453, 2LMP, and the gastric cancer cell of N87 treated with single or drug combination., Results: In MDA-MB-453 and N87 with high expression of erbB-2, 3, 4, percentage of the apoptosis cell was significantly higher in the group treated with the drug combination than that in the group treated with the single drug (P < 0.01). To the contrast, in 2LMP cells with low expression of erbB-2, 3, 4, there was no difference between the drug combination and the single drug group (P > 0.05). In MDA-MB-453 and N87, degradation of PARP, caspase-3 was more in the group treated with the drug combination than that in the group treated with the drug alone. Overexpressions of bcl-2, mp53 were inhibited in the group treated by the drug combination. On the contrary overexpressions of bcl-2, mp53 were not inhibited in the group treated with the single drug. While these changes of PARP[poly (ADP)-ribose polymerase], caspase-3, mp53, bcl-2 could not be observed in the control cell line of 2LMP., Conclusions: The combination of HEL beta 1-PE38KDEL and cis-platin could promote the synergistic effect on apoptosis in the target cancer cells with high expression of erbB-2, 3, 4 which might be one of the mechanism of these two drugs.

Objective: The purpose of this study was to develop an imaging technique to measure and monitor tumor cells undergoing programmed death caused by radiation and chemotherapy using 99mTc-EC-annexin V. Annexin V has been used to measure programmed cell death both in vitro and in vivo. Assessment of apoptosis would be useful to evaluate the efficacy and mechanisms of therapy and disease progression or regression., Methods: Ethylenedicysteine (EC) was conjugated to annexin V using sulfo-N-hydroxysuccinimide and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide-HCl as coupling agents. The yield of EC-annexin V was 100%. In vitro cellular uptake, pre- and post-radiation (10-30 Gy) and paclitaxel treatment, was quantified using 99mTc-EC-annexin V. Tissue distribution and planar imaging of 99mTc-EC-annexin V were determined in breast tumor-bearing rats at 0.5, 2, and 4 hrs. To demonstrate in vivo cell apoptosis that occurred during chemotherapy, a group of rats was treated with paclitaxel and planar imaging studies were conducted at 0.5-4 hrs. Computer outlined region of interest (ROI) was used to quantify tumor uptake on day 3 and day 5 post-treatment., Results: In vitro cellular uptake showed that there was significantly increased uptake of 99mTc-EC-annexin V after irradiation (10-30 Gy) and paclitaxel treatment. In vivo biodistribution of 99mTc-EC-annexin in breast tumor-bearing rats showed increased tumor-to-blood, tumor-to-lung and tumor-to-muscle count density ratios as a function of time. Conversely, tumor-to-blood count density ratios showed a time-dependent decrease with 99mTc-EC in the same time period. Planar images confirmed that the tumors could be visualized clearly with 99mTc-EC-annexin. There was a significant difference of ROI ratios between pre- and post-paclitaxel treatment groups at 2 and 4 hrs post injection., Conclusion: The results indicate that apoptosis can be quantified using 99mTc-EC-annexin and that it is feasible to use 99mTc-EC-annexin to image tumor apoptosis.