Colorectal cancer cell dormancy:An insight into pathways

Cancer cell dormancy(CCD)in colorectal cancer(CRC)poses a significant challenge to effective treatment.In CRC,CCD contributes to tumour recurrence,drug resistance,and amplifying the disease's burden.The molecular mechanisms governing CCD and strategies for eliminating dormant cancer cells remain largely unexplored.Therefore,understanding the molecular mechanisms governing dormancy is crucial for improving patient outcomes and developing targeted therapies.This editorial highlights the complex interplay of signalling pathways and factors involved in colorectal CCD,emphasizing the roles of Hippo/YAP,pluripotent transcription factors such as NANOG,HIF-1αsignalling,and Notch signalling pathways.Additionally,ERK/p38α/β/MAPK pathways,AKT signalling pathway,and Extracellular Matrix Metalloproteinase Inducer,along with some potential less explored pathways such as STAT/p53 switch and canonical and non-canonical Wnt and SMAD signalling,are also involved in promoting colorectal CCD.Highlighting their clinical significance,these findings may offer the potential for identifying key dormancy regulator pathways,improving treatment strategies,surmounting drug resistance,and advancing personalized medicine approaches.Moreover,insights into dormancy mechanisms could lead to the development of predictive biomarkers for identifying patients at risk of recurrence and the tailoring of targeted therapies based on individual dormancy profiles.It is essential to conduct further research into these pathways and their modulation to fully comprehend CRC dormancy mechanisms and enhance patient outcomes.

Suppressive effects of exercise-conditioned serum on cancer cells:A narrative review of the influence of exercise mode,volume,and intensity

Cancer is a major cause of morbidity and mortality worldwide,and the incidence is increasing,highlighting the need for effective strategies to treat this disease.Exercise has emerged as fundamental therapeutic medicine in the management of cancer,associated with a lower risk of recur-rence and increased survival.Several avenues of research demonstrate reduction in growth,proliferation,and increased apoptosis of cancer cells,including breast,prostate,colorectal,and lung cancer,when cultured by serum collected after exercise in vitro(i.e.,the cultivation of cancer cell lines in an experimental setting,which simplifies the biological system and provides mechanistic insight into cell responses).The underlying mechanisms of exercise-induced cancer suppressive effects may be attributed to the alteration in circulating factors,such as skeletal muscle-induced cytokines(i.e.,myokines)and hormones.However,exercise-induced tumor suppressive effects and detailed information about training interventions are not well investigated,constraining more precise application of exercise medicine within clinical oncology.To date,it remains unclear what role different training modes(i.e.,resistance and aerobic training)as well as volume and intensity have on exercise-condi-tioned serum and its effects on cancer cells.Nevertheless,the available evidence is that a single bout of aerobic training at moderate to vigorous intensity has cancer suppressive effects,while for chronic training interventions,exercise volume appears to be an influential candidate driving cancer inhibitory effects regardless of training mode.Insights for future research investigating training modes,volume and intensity are provided to further our understanding of the effects of exercise-conditioned serum on cancer cells.

Estimation of cancer cell migration in biomimetic random/oriented collagen fiber microenvironments

Increasing data indicate that cancer cell migration is regulated by extracellular matrixes and their surrounding biochemical microenvironment,playing a crucial role in pathological processes such as tumor invasion and metastasis.However,conventional two-dimensional cell culture and animal models have limitations in studying the influence of tumor microenvironment on cancer cell migration.Fortunately,the further development of microfluidic technology has provided solutions for the study of such questions.We utilize microfluidic chip to build a random collagen fiber microenvironment(RFM)model and an oriented collagen fiber microenvironment(OFM)model that resemble early stage and late stage breast cancer microenvironments,respectively.By combining cell culture,biochemical concentration gradient construction,and microscopic imaging techniques,we investigate the impact of different collagen fiber biochemical microenvironments on the migration of breast cancer MDA-MB-231-RFP cells.The results show that MDA-MB-231-RFP cells migrate further in the OFM model compared to the RFM model,with significant differences observed.Furthermore,we establish concentration gradients of the anticancer drug paclitaxel in both the RFM and OFM models and find that paclitaxel significantly inhibits the migration of MDA-MB-231-RFP cells in the RFM model,with stronger inhibition on the high concentration side compared to the low concentration side.However,the inhibitory effect of paclitaxel on the migration of MDA-MB-231-RFP cells in the OFM model is weak.These findings suggest that the oriented collagen fiber microenvironment resembling the late-stage tumor microenvironment is more favorable for cancer cell migration and that the effectiveness of anticancer drugs is diminished.The RFM and OFM models constructed in this study not only provide a platform for studying the mechanism of cancer development,but also serve as a tool for the initial measurement of drug screening.

UBE2T mediates the stemness properties of breast cancer cells through the mTOR signaling pathway

Objectives:This study aimed to reveal the role and possible mechanism of the ubiquitin-conjugating enzyme 2T(UBE2T)in the biological activities of breast cancer stem cells(BCSCs).Methods:The specific protein and gene expression were quantified by Western blotting and quantitative real-time polymerase chain reaction,the proportion of BCSCs was examined by flow cytometry,and the self-renewal and proliferation of BCSCs were verified by serial sphere formation and soft agar.Results:Increasing expression of UBE2T was drastically found in breast cancer than that in adjacent tissues.Furthermore,UBE2T overexpression significantly increased the proportion of BCSCs in breast cancer cells and promoted their self-renewal and proliferation.Silent UBE2T exhibited the opposite functions.UBE2T increased the levels of the mammalian target of rapamycin and the phosphorylated mammalian target of rapamycin.Mammalian target of rapamycin(mTOR)inhibitor rapamycin inhibited the function of UBE2T in BCSCs.Conclusion:UBE2T plays a role in BCSCs through mTOR pathway and may suggest a novel therapeutic strategy for breast cancer.

Anti-proliferative effect of Annona extracts on breast cancer cells

Backgorund:Fruits and seed extracts of Annona montana have significant cytotoxic potential in several cancer cells.This study evaluates the effect of A.montana leaves hexane extract on several signaling cascades and gene expression in metastatic breast cancer cells upon insulin-like growth factor-1(IGF-1)stimulation.Methods:MTT assay was performed to determine the proliferation of cancer cells.Propidium iodide staining and flow cytometry analysis of Annexin V binding was utilized to measure the progression of the cell cycle and the induction of apoptosis.Protein expression and phosphorylation were determined by western blotting analysis to examine the underlying cellular mechanism triggered upon treatment with A.montana leaves hexane extract.Results:A.montana leaves hexane(subfraction V)blocked the constitutive stimulation of the PI3K/mTOR signaling pathways.This inhibitory effect was associated with apoptosis induction as evidenced by the positivity with Annexin V and terminal deoxynucleotidyl transferase dUTP nick end labeling(TUNNEL)staining,activation of caspase-3,and cleavage of PPAR.It also limited the expression of various downstream genes that regulate proliferation,survival,metastasis,and angiogenesis(i.e.,cyclin D1,survivin,COX-2,and VEGF).It increased the expression of p53 and p21.Interestingly,we also observed that this extract blocked the activation of AKT and ERK without affecting the phosphorylation of the IGF-1 receptor and activation of Ras upon IGF-1 stimulation.Conclusion:Our study indicates that A.montana leaves(sub-fraction V)extract exhibits a selective anti-proliferative and proapoptotic effect on the metastatic MDA-MB-231 breast cancer cells through the involvement of PI3K/AKT/mTOR/S6K1 pathways.

Surface activity of cancer cells:The fusion of two cell aggregates

A key feature that distinguishes cancer cells from all other cells is their capability to spread throughout the body.Although how cancer cells collectively migrate by following molecular rules which influence the state of cell-cell adhesion contacts has been comprehensively formulated,the impact of physical interactions on cell spreading remains less understood.Cumulative effects of physical interactions exist as the interplay between various physical parameters such as(1)tissue surface tension,(2)viscoelasticity caused by collective cell migration,and(3)solid stress accumulated in the cell aggregate core region.This review aims to point out the role of these physical parameters in cancer cell spreading by considering and comparing the rearrangement of various mono-cultured cancer and epithelial model systems such as the fusion of two cell aggregates.While epithelial cells undergo volumetric cell rearrangement driven by the tissue surface tension,which directs cell movement from the surface to the core region of two-aggregate systems,cancer cells rather perform surface cell rearrangement.Cancer cells migrate toward the surface of the two-aggregate system driven by the solid stress while the surface tension is significantly reduced.The solid stress,accumulated in the core region of the two-aggregate system,is capable of suppressing the movement of epithelial cells that can undergo the jamming state transition;however,this stress enhances the movement of cancer cells.We have focused here on the multi-scale rheological modeling approaches that aimed at reproducing and understanding these biological systems.

Simultaneous Morphologies and Luminescence Control of NaYF_(4)∶Yb/Er Nanophosphors by Surfactants for Cancer Cell Imaging

Hydrophilic rare-earth up-conversion nanophosphors(UCNPs)with small sizes and a strong up-conversion luminescence have attracted much interest.Herein the simultaneous control of morphologies and the up-conversion luminescence intensities was reported for NaYF_(4)∶Yb/Er nanophosphors by a facile hydrothermal procedure with different surfactants.With the change of the surfactants from polyvinylpyrrolidone(PVP)to sodium citrate(CIT),edetate disodium(EDTA)or sodium dodecyl benzenesulfonate(SDBS),the morphology of NaYF_(4)∶Yb/Er nanophosphors transformed from nanoparticles with a diameter of about 70.0 nm to hexagonal nanoblocks with a thickness of about 125.0 nm and a length of about 240.0 nm,nanorods with a diameter of about 700.0 nm and a length of about 2.6μm,or nanowires with a diameter of 250.0 nm and a length of about 3.2μm.Simultaneously,their up-conversion luminescence intensity went down gradually under laser irradiation at a wavelength of 980 nm due to the increase of photobleaching.PVP-capped NaYF_(4)∶Yb/Er nanoparticles exhibited the smallest size and the strongest up-conversion luminescence intensity.Biological experiment results revealed that NaYF_(4)∶Yb/Er nanophosphors exhibited a high biocompatibility and could be used as biological labels with a perfect signal-to-noise ratio for cancer cell imaging.

The Role of NF-κB p65 in White Tea Aqueous Extract-Induced Cancer Cell Apoptosis

White tea encompasses a number of teas unique to eastern Fujian in China. Although white tea extracts have been reported to result in cancer cell apoptosis, to date, few studies have evaluated the mechanism of such apoptotic induction. A transcription factor that plays a critical role in cell apoptosis, NF-κB p65, is also likely critical by which white tea extracts induce cancer cell apoptosis. In this study, white tea aqueous extract (WTAE) was added to BEL-7402 and Hela cell media and NF-κB p65 activation was evaluated using western blotting and immunofluorescence. Results revealed that the phosphorylation of IKBα and p65 decreased in both cell lines after WTAE treatment. And the nuclear translocation of NF-κB p65 in both cell lines was also reduced with the WTAE treatment. NF-κB p65 inhibition was noted to accelerate apoptosis. Our findings suggest that NF-κB p65 was an important modulator in WTAE-induced apoptotic signal transduction and it acted as a negative regulator of apoptotic induction in BEL-7402 and Hela cancer cell lines.

Toxic chemotherapeutic nutrition of cancer cells by alkaline glucosodiene molecules via targeting metabolic of cancerous tumors: a promising theory for cancer treatment

Cancer is a genetic disease characterized by heritable defects in cellular regulatory mechanisms.Tumor cells must adapt their metabolism to survive and proliferate in the challenging conditions of the tumor microenvironment.To maintain uncontrolled cellular growth and survival,cancer cells alter their metabolism,which makes them dependent on a steady supply of nutrients and energy.Almost a century ago,the Warburg theory suggested that cancer cells consume glucose even in the presence of oxygen.Recent studies have confirmed that cancer cells indeed consume significantly more glucose than normal cells.Cancerous tumors require an acidic microenvironment with low oxygen levels for growth and spread.However,recent advances in pH measurement have shown that the intracellular pH of cancer cells is neutral or slightly alkaline compared to normal tissue cells.This finding indicates that not all tumors are highly acidic.Taking advantage of cancer cells’high glucose consumption,a strategy to lyse cancer cells is tested by means of glucose modifications that exploit the characteristics of their uncontrolled growth process.From the study of the molecular structure to give him alkaline properties that enable him to make defects in the tumor structure and possibly achieve cell killing,this situation will have a killing effect on cancer cells if small molecules of toxic atoms(alkaline atoms)can be continuously supplied to them through food,due to the uncontrolled consumption of glucose molecules by cancer cells.This theory attempts to investigate by changing the atomic structure of glucose molecules to make them alkaline glucosodiene molecules as one of the methods to kill cancer cells.By preparing alkaline glucosodiene molecules and performing animal experiments and histological observations,it was shown that tumors without alkaline treatment showed a tendency to infiltrate and grow,while tumors treated with glucosodiene molecules showed complete disappearance of cell structure and nucleolysis,supporting the validity of the theory.

How the interplay among the tumor microenvironment and the gut microbiota influences the stemness of colorectal cancer cells

Colorectal cancer(CRC)remains the third most prevalent cancer disease and involves a multi-step process in which intestinal cells acquire malignant characteristics.It is well established that the appearance of distal metastasis in CRC patients is the cause of a poor prognosis and treatment failure.Nevertheless,in the last decades,CRC aggressiveness and progression have been attributed to a specific cell population called CRC stem cells(CCSC)with features like tumor initiation capacity,self-renewal capacity,and acquired multidrug resistance.Emerging data highlight the concept of this cell subtype as a plastic entity that has a dynamic status and can be originated from different types of cells through genetic and epigenetic changes.These alterations are modulated by complex and dynamic crosstalk with environmental factors by paracrine signaling.It is known that in the tumor niche,different cell types,structures,and biomolecules coexist and interact with cancer cells favoring cancer growth and development.Together,these components constitute the tumor microenvironment(TME).Most recently,researchers have also deepened the influence of the complex variety of microorganisms that inhabit the intestinal mucosa,collectively known as gut microbiota,on CRC.Both TME and microorganisms participate in inflammatory processes that can drive the initiation and evolution of CRC.Since in the last decade,crucial advances have been made concerning to the synergistic interaction among the TME and gut microorganisms that condition the identity of CCSC,the data exposed in this review could provide valuable insights into the biology of CRC and the development of new targeted therapies.

A novel synthesized prodrug of gemcitabine based on oxygen-free radical sensitivity inhibited the growth of lung cancer cells

In the present study,we introduced the H2O2-sensitive thiazolidinone moiety at the 4th amino group of gemcitabine(GEM)to synthesize a new target compound named GEM-ZZQ,and then we confirmed its chemical structure by nuclear magnetic resonance spectroscopy.We further confirmed that GEM-ZZQ had a good chemical stability in different pH solutions in vitro and that it could be activated by H2O2 to release GEM.Pharmacodynamic studies revealed that the growth inhibition of human normal epithelial cells was weaker by GEM-ZZQ than by GEM treatment and that the inhibition of various lung cancer cell lines by GEM-ZZQ was similar to that of GEM.For the lung cancer cell lines that are resistant to the epidermal growth factor receptor(EGFR)-targeting inhibitor osimertinib,GEM-ZZQ showed less growth inhibition than GEM;however,GEM-ZZQ in combination with cisplatin showed better synergistic effects than GEM in the low-dose groups.In summary,we provided a new anti-cancer compound GEM-ZZQ for treating lung cancer by modifying the GEM structure.

Screening of the Metastasis-Associated Genes by Gene Chip in High Metastatic Human Ovarian Cancer Cell Lines

Affymetrix U133A oligonucleotide microarrays were used to study the differences of gene expressions between high （H） metastatic ovarian cancer cell line, HO-8910PM, and normal ovarian tissues （C）. Bioinformatics was used to identify their chromosomal localizations. A total of 1,237 genes were found to have a difference in expression levels more than eight times. Among them 597 were upregulated [Signal Log Ratio （SLR） ≥3], and 640 genes were downregulated （SLR≤-3）. Except one gene, whose location was unknown, all these genes were randomly distributed on all the chromosomes. However, chromosome 1 contained the most differentially expressed genes （115 genes, 9.3%）, followed by chromosome 2 （94 genes, 7.6%）, chromosome 12 （88 genes, 7.1%）, chromosome 11 （76 genes, 6.1%）, chromosomes X （71 genes, 5.7%）, and chromosomes l7 （69 genes, 5.6%）. These genes were localized on short-arm of chromosome （q）, which had 805 （65.1%） genes, and the short arms of No.13, 14, 15, 21, and 22 chromosomes were the only parts of the chromosomes where the differentially expressed genes were localized. Functional classification showed that most of the genes （306 genes, 24.7%） belonged to the enzymes and their regulator groups. The subsequent group was the nucleic acid binding genes （144 genes, 11.6%）. The rest of the top two groups were signal transduction genes （137 genes, 11.1%） and proteins binding genes （116 genes, 9.4%）. These comprised 56.8% of all the differentially expressed genes. There were also 207 genes whose functions were unknown （16.7 %）. Therefore it was concluded that differentially expressed genes in high metastatic ovarian cancer cell were supposed to be randomly distributed across the genome, but the majority were found on chromosomes 1, 2, 12, 11, 17, and X. Abnormality in four groups of genes, including in enzyme and its regulator, nucleic acid binding, signal transduction and protein binding associated genes, might play important roles in ovarian cancer metastasis. Those genes need to be further studied.

IN SITU IMAGING OF BREAST CANCER CELLS USING GREEN SEMICONDUCTOR QUANTUM DOTS

The breast cancer is the most common cause of cancer death in women. To establish an early stage in situ imaging of breast cancer cells, green quantum dots （QDs） are used as a fluorescent signal generator. The QDs based imaging of breast cancer cells involves anti-HER2/neu antibody for labeling the over expressed HER2 on the surface of breast cancer cells. The complete assay involves breast cancer cells, biotin labeled antibody and streptavidin conjugated QDs. The breast cancer cells are grown in culture plates and exposed to the biotin labeled antibodies, and then exposed to streptavidin labeled QDs to utilize the strong and stable biotin-streptavidin interaction. Fluorescent images of the complete assay for breast cancer cells are evaluated on a microscope with a UV light source. Results show that the breast cancer cells in the complete assay are used as fluorescent cells with brighter signals compared with those labeled by the organic dye using similar parameters and the same number of cells.

The Continuous Relative Deficiency of Intracellular Potassium Is a Core Mechanism for the Occurrence and Metastasis of Tumor Cancer Cells

The core mechanism for occurrence of tumor cancer cells is related to the continuous relative deficiency of potassium ions in the cells of organs and tissues, which results in embryonic like proliferation and differentiation in the affected cells. The purpose of the metastasis of cancer cells is to obtain and utilize the potassium resources in other organs in body. However, if the overall potassium storage in body is obviously insufficient, the metastatic cancer cells still fail to achieve the purpose of obtaining enough potassium and turn into normal cells, further proliferation and differentiation of cancer cells will continue, and finally will lead to functional decline in the organs and tissues affected or death. Therefore, the key means to prevent and treat tumors and cancers is to ensure the normal and balanced potassium ions in cells in various organs and tissues, so as to avoid the formation of tumors and cancer cells caused by obvious deficiency of potassium ions.

Cytotoxic Effect of Chitosan Based Nanocomposite Synthesized by Radiation： In Vitro Liver and Breast Cancer Cell Line

A silver nanoparticle （AgNP） is likely to provide an attractive object for combining a variety of biochemical properties with great therapeutic potential by using radiation. The present study explores the ICs0 value of chitosan-poly （vinyl alcohol） hydrogel （Cs/PVA） and Ag-doped chitosan-poly （vinyl alcohol） （Cs/PVA/Ag） nanocomposite in view of their anticancer application. The aim was to develop （Cs/PVA） based hydrogel synthesized by gamma radiation which could behave both as a nanoreactor for Ag nanoparticle with promising anticancer applications. The （Cs/PVA/Ag） nanocomposite was confirmed by FTIR （Fourier transform infrared） spectroscopy, XRD （X-ray diffraction） and EDX （energy dispersive X-ray） analysis. The anti-cancer activity of the prepared nanocomposites was demonstrated in human liver cancer cell line （HEPG2） and breast cancer cell lines （MCF7）. It has significant effects against human liver cancer cell line HEPG2 compared to breast cancer cell line MCF7. Further quantitative analysis on the molecular and protein levels is still required to confirm the impact of chitosan on genotoxic effect before reaching a final conclusion and starting its biomedical application.

Effect of poly(ethylene glycol) modified polyethylenimine polyelectrolyte complex on pharmaceutical characteristics and uptake on breast cancer cell

Cationic polyethylenimine （PEI） with dextran fluorescein anionic （DFA） or oligodeoxynucleotide （ODN） could form polyelectrolyte complex by self-assembly as a gene delivery vector. This study was designed to investigate the effects on pharmaceutical characteristics and cell uptake PEI after a long-circulation modification with poly（ethylene glycol） （PEG）. DFA or ODN reacted with PEI or PEI-PEG to form polyelectrolyte complexes. Surface characters of these complexes and the retardation of ODN by PEI and PEI-PEG were evaluated. The uptake rates of DFA/PEI and DFA/PEI-PEG complexes by MCF-7 cells were evaluated by flow cytometry. Confocal laser scanning microscopy was utilized to visualize the internalization of these complexes. ODN/PEI complex showed the dependence of their size and ξ potential on the N/P ratio. ODN/PEI-PEG complex were much less affected by N/P ratio and their size was around 30 100 nm. PEI and PEI-PEG retarded ODN even at N/P ratio as low as 4, and complete retardation was found at N/P ratio of 8. The uptake rate by MCF-7 cells was direct correlated to the DFA concentration and incubation time, and the uptake rate could exceed 99% under the selected condition. The results in this study showed that PEI self-assembly polyelectrolyte complex after stealth or long circulation modification may increase the ability as a gene vector to delivery genes into cells.

Induction of antiproliferative effect by diosgenin through activation of p53, release of apoptosis-inducing factor (AIF) and modulation of caspase-3 activity in different human cancer cells

Previously, we demonstrated that a plant steroid, diosgenin, altered cell cycle distribution and induced apoptosis in the human osteosarcoma 1547 cell line. The objective of this study was to investigate if the antiproliferative effect of diosgenin was similar for different human cancer cell lines such as laryngocarcinoma HEp-2 and melanoma M4Beu cells. Moreover, this work essentially focused on the mitochondrial pathway. We found that diosgenin had an important and similar antiproliferative effect on different types of cancer cells. In addition, our new results show that diosgenininduced apoptosis is caspase-3 dependent with a fall of mitochondrial membrane potential, nuclear localization of AIF and poly (ADP-ribose) polymerase cleavage. Diosgenin treatment also induces p53 activation and cell cycle arrest in the different cell lines studied.

Epigenetic modification regulates both expression of tumor-associated genes and cell cycle progressing in human colon cancer cell lines: Colo-320 and SW1116

The aim of this study is to assess the effects of DNA methylation and historic acetylation, alone or in combination, on the expression of several tumor-associated genes and cell cycle progression in two established human colon cancer cell lines: Colo-320 and SW1116. Treatments with 5-aza-2'-deoxycytidine (5-aza-dC) and trichostatin A, alone or in combination, were applied respectively. The methylation status of the CDKN2A promoter was determined by methyla-tion-specific PCR, and the acetylated status of the histones associated with the p21WAF1 and CDKN2A genes was examined by chromatin immunoprecipitation. The expression of the CDKN2A, p21WAF1, p53, p73, APC, c-myc, c-Ki-ras and survivin genes was detected by real-time RT-PCR and RT-PCR. The cell cycle profile was established by flow cytometry. We found that along with the demethylation of the CDKN2A gene promoter in both cell lines induced by 5-aza-dC alone or in combination with TSA, the expression of both CDKN2A and APC genes increased. The treatment of TSA or sodium butyrate up-regulated the transcription of p21WAF1 significantly by inducing the acetylation of histones H4 and H3, but failed to alter the acetylation level of CDKN2A-associated histones. No changes in transcription of p53, p73, c-myc, c-Ki-ras and survivin genes were observed. In addition, TSA or sodium butyrate was shown to arrest cells at the G1 phase. However, 5-aza-dC was not able to affect the cell cycle progression. In conclusion, regulation by epigenetic modification of the transcription of tumor-associated genes and the cell cycle progression in both human colon cancer cell lines Colo-320 and SW1116 is gene-specific.

KAI1 is a potential target for anti-metastasis in pancreatic cancer cells

AIM: To investigate whether KAI1, as a metastasis suppressor gene, is associated with invasive and metastatic ability of pancreatic cancer cells.METHODS: KAI1 gene was transfected into pancreatic cancer cell line MiaPaCa Ⅱ by liposomes selected with G418. Expression of transfected cells was measured by Western blotting, immunofluorescence and immunocytochemistry. Tumor cell invasion and metastatic ability were detected through gelatinase activity and reconstituted basement membrane (Matrigel) assay. pCMV-KAI1 was directly injected into the heterotopic human pancreatic adenocarcinoma successfully established in the groin of BALB/C nude mice, by subcutaneous injection of MiaPaCa Ⅱ pancreatic cancer cells. The statistical analysis between groups was determined by Student's two tailed t test.RESULTS: By Western blotting, MiaPaCa Ⅱ cells transfected by KAI1 gene indicated KAI1 expression at approximately 29.1 kDa. Cytoplasm staining was positive and uniformly spread in transfected cancer cells, using immunohistochemistry and immunofluorescence. The most obvious difference was present after 30 h (MiaPaca Ⅱ 43.6 ± 9.42, pCMV-MiaPaca Ⅱ 44.8 ± 8.56, pCMV-KAI1-MiaPaca Ⅱ 22.0 ± 4.69, P < 0.05). Gelatinolysis revealed a wider and clearer band of gelatinolytic activity in non-transfected than in transfected cells (MiaPaCa Ⅱ cells 30.8 ± 0.57, transfected cells 28.1 ± 0.65, P < 0.05). In vivo tumor growth rates of KAI1 transfectants with KAI1-Lipofectamine 1.22 ± 0.31 in A group were lower than control 4.61 ± 1.98 and pCMV-KAI 11.67 ± 0.81. Analyses of metastases with and without KAI1 transfection in mice were different in liver and lung between controls 1.62 ± 0.39, 0.45 ± 0.09, pCMV-KAI 1.01 ± 0.27, 0.33 ± 0.09 and KAI1-Lipofectamine 0.99 ± 0.21, 0.30 ± 0.09 respectively (P < 0.05).CONCLUSION: High expression of KAI1 gene was found in transfected MiaPaCa Ⅱ human pancreatic cancer cells with lower metastatic ability. KAI1 gene plays an important role in inhibiting metastasis of pancreatic cancer after direct injection into pancreatic adenocarcinoma. These results show that the suppressed invasion and motor function of pancreatic cancer cells may be a key reason why the KAI1 gene controls pancreatic cancer cell metastasis.

Effects of simulated carbon dioxide and helium peumoperitoneum on proliferation and apoptosis of gastric cancer cells

AIM:To investigate the effects of carbon dioxide (CO2) and helium insufflation administered at different pressures on the growth and apoptosis of cultured human gastric cancer cells. METHODS:The gastric cancer cells MKN-45 were exposed to a CO2 and helium environment maintained at different pressures (0, 5, 10 and 15 mmHg). The cells were exposed to simulated pneumoperitoneum environment for 4 h, and pH of the culture media was measured after it was moved to normal conditions for 0, 2, 4, 6 and 8 h. Proliferation viability of MKN-45 was examined by 3-4,5Dimethylthiazol-2-yl,5-diphenyltetrazolium bromide or triazolyl blue (MTT) assay after it was moved to normal conditions. Apoptotic ratio was measured by Annexin V-FITC/PI double labelled staining. RESULTS:The pH of media was acid and recovered to normal after 4 h in the CO2 group while it was basic in the helium group. There was no difference between CO2 groups (under 10 mmHg ) and control group (P > 0.05) in the proliferative viability of the cells. The cultured cells exposed to 15 mmHg CO2 environment grew more slowly than control group from 4 to 7 d (P < 0.01 ) while there was no difference from 1 to 3 d (P > 0.05). The proliferative viability in helium group was not obviously different from the control group (P > 0.05). The apoptotic ratio of the cultured cells was markedly higher than that of the control group (P < 0.01) at 10 and 15 mmHg CO2 insufflation pressure. In helium group, the apoptotic ratio was not obviously different from the control group (P > 0.05). CONCLUSION:There is no obvious effect in the proliferation and apoptosis of MKN-45 cells under 10 mmHg CO2 insufflation pressure and helium in any pressure. Fifteen mmHg CO2 insufflation pressure can inhibit the proliferation of the cells and improve apoptosis.