| Epithelial ovarian cancer （EOC） is the most common form of ovariancancer, and the overall5-year survival rate is only15–30%. Most patients withEOC will exhibit a satisfactory initial clinical response to optimalcytoreductive surgery followed by systemic paclitaxel-and platinum-basedchemotherapy, but unfortunately, the majority of patients will developrecurrence with latency periods that range from years to even decades. Thispause can be explained by tumor dormancy, which represents a subclinicalequilibrium between host immunity and quiescent residual tumor cells andalso represents the minimal residual disease, a stage that remains a majorobstacle in achieving complete remission. In recent years, tumor dormancyassociated with cancer stem cells （CSCs） has been extensively speculated.Although it is unclear whether CSCs are indeed the cells that harbor thegenetic alterations that cause cancer, primeval traits of adult stem cells mightpotentially explain tumor cell dormancy, such as their quiescence within aniche that is critical in tissue proliferation and protection of tissue homeostasis.Therefore, it was hypothesized that disease relapse is the consequence ofCSCs which subsequently resume growth after undergoing a quiescent state.The insulin-like growth factor （IGF） signaling axis plays a pivotal role intumor progression. Most, if not all, of the effects of IGF result from itsactivation of the IGF-1R, whose signaling is required for maintenance ofgrowth and tumorigenicity of many tumors. Phosphorylation of theinsulin-like growth factor receptor1（IGF-1R） occurs following binging withits ligand, the IGF-1and IGF-2. This induces the recruitment of severaleffector molecules, in turn activating the downstream PI3K/AKT signalingcascade. This cascade plays a major role in normal growth and development, and is also implicated in mediating proliferation and protecting apoptosis.IGF-1R is frequently overexpressed in ovarian cancer and ovarian cancer celllines and is known to play key roles in the transformed phenotype of ovariancancer cells. It will be important to investigate the relationship between IGFand the proliferation of dormant cells within epithelial ovarian cancerxenografts.In the present study, we developed mouse xenograft models and exploredthe ‘stemness’ of label-retaining PKH26hicells （i.e. dormant/slow-cyclingovarian cancer cells）, such as the expression of stem cell markers andtumorigenicity. More importantly, chemotherapy was applied to xenografttumors generated in mice which were injected with ovarian cancer cellsSKOV3, and tumor growth and side effects were monitored. When thexenograft tumors stopped growing in the presence of chemotherapy coexistingwith their host at a stable size, the stem-like characteristics ofdormant/slow-cycling PKH26hicells were analyzed. Subsequently, weobserved that IGF-1R modulates proliferation of dormant cancer stem cells inepithelial ovarian cancer and the IGF-1R inhibitor NVP was used to observethe change of cell proliferation and apoptosis of SKOV3-R-PKH26hicells.Part1Stem cell characteristics of dormant cells and cisplatin–inducedeffects on the stemness of epithelial ovarian cancer cellsObjective: Tumor dormancy is not only a biological property ofmalignances but is also a crucial cause of treatment failure, metastasis, andtumor recurrence. The present study aimed to examine stem cellcharacteristics of dormant cells and cisplatin–induced effects on the stemnessof epithelial ovarian cancer cells.Methods and meterials:1PKH26labeling was performed according to the manufacturer’sinstructions.2Animal housing, generation of tumors, and cisplatin treatmentFor subcutaneous （s.c.） tumor formation, PKH26-labeled SKOV3cells（1×107） were suspended in0.5ml of phosphate-buffered saline （PBS） and s.c. injected into the left thigh of each nude mouse. Approximately14days later（average tumor volume100mm3）, the mice were randomly separated into twogroups as follows: a control group of mice （SKOV3-P xenograft tumors） and atreatment group of mice was treated with cisplatin （i.p. injection of4mg/kgcisplatin twice a week for3weeks, SKOV3-R xenograft tumors）. Theexperiments were terminated if the tumor size of the control group reached1500mm3or the tumors of the treatment group coexisted with their host at astable size after the end of treatment for at least one week.3Tumor growth and side effectsThe mice were closely monitored every day and body weights and tumorvolumes were measured every6days. During the experiment period, any sideeffects of the chemotherapy, such as weight loss, changes in behavior andfeeding, reaction to stimulation and ruffing of fur were observed and recorded.4Tumor digestion for PKH26-based sorting and analysis by flowcytometryPKH26hi, PKH26low, and PKH26negcells were identified, gated and sortedbased on the fluorescence intensity of this continuous gradient for subsequentexperiments. PKH26-based sorting was performed on a FACSAria and datawere analyzed with FACSDiva software.5DNA content was analyzed by flow cytometry on FACSAria and theproportion of cells in a particular phase of the cell cycle was determined withModFit LT software.6Real-time RT-PCR analysis was used to measure the expression levelsof stem cell markers Nestin, Oct3/4, CD117and CD44in three sorted groupsof PKH26cells from SKOV3-P and SKOV3-R tumors.7Flow cytometric analysis was used to detect the protein expression ofstem cell markers Nestin, Oct3/4, CD117and CD44in three groups of PKH26cells from SKOV3-P and SKOV3-R tumors.8Clonogenicity assays were performed to determine the initiating tumorcapacity of the three fractions of PKH26-retaining cells （PKH26hi, PKH26low,and PKH26neg） from SKOV3-P and SKOV3-R tumors. 9Tumorigenicity assays were performed to determine the tumorigenicityof the three fractions of PKH26-retaining cells （PKH26hi, PKH26low, andPKH26neg） from SKOV3-P and SKOV3-R tumors.Results:1Efficiency of PKH26-labeled SKOV3cellsThe PKH26-labeled SKOV3cells emitted red under fluorescencemicroscope and labeling efficiency could achieve to100%. It was qualified tosubsequent experiment requirement.2Tumor growth and mouse condition assessmentFor tumor formation,1×107PKH26-labeled SKOV3cells were s.cinjected into the thighs of mice （n=70）. Engrafted mice （average tumorvolume100mm3） were randomly assigned into two groups after injection for14days: the control group （n=35） and the treatment group （n=35）. There wasno significant difference in xenograft tumor volumes between the two groups（102.9±16.69mm3vs.104.7±13.43mm3, P=0.793）.On day35（upon completion of cisplatin treatment）, all the control groupmice had larger xenograft tumors and engrafted mice treated with cisplatinshowed a significant inhibition in tumor volume as compared with the controlgroup （1089.95±82.37mm3vs.535.7±44.69mm3, P<0.05）. An assessmentof the growth rate revealed no significant difference from day14to day21,but from day21to day28the decrease in the growth rate of cisplatin-treatedtumors was only one third of the control group （17.82±3.24mm3/day vs.50.14±2.92mm3/day, P<0.05）. From day28to day35, the growth rate of thetreated tumors was about one fifth of the untreated tumors （11.72±3.52mm3/day vs.51.67±15.59mm3/day, P<0.05）. One week after the end oftreatment （day42）, the mean of tumor volume in treatment group had notincreased significantly compared with the tumor volume on day35（P>0.05）,but a significant difference existed between the control group and thetreatment group （1511.76±61.53mm3vs.535.03±47.29mm3, P<0.05）. Twogroups of mice reached the breeding termination standard on day42and themice were sacrificed. Following sacrifice of the mice, a significant difference in the weight of the tumors was observed between the two groups （4.72±0.46g for the SKOV3-P tumors vs.1.03±0.11g for the SKOV3-R tumors,P<0.05）.At the end of cisplatin treatment （day35）, the mice treated with cisplatinexhibited a series of side effects, consisting of weight loss （21.41±0.74g forthe mice of control group vs.19.32±0.67g for the mice treated with cisplatin,P<0.05）, short-time drowsiness, mild skin discoloration, diet decline （3.63±0.22g/day for the mice of control group vs.1.96±0.15g/day for the micetreated with cisplatin, P<0.05） and leucopenia （7.41±0.15×109/L for the miceof control group vs.6.86±0.31×109/L for the mice treated with cisplatin,P<0.05）. Although chemotherapy caused a series of side effects, the mice hada certain extent of tolerance to chemotherapy based on the grading criteria ofthe side effects.3Dormant/quiescent PKH26hicells existed in xenograft tumors andcisplatin led to enrichmentAnalyses of SKOV3-P tumors for the distribution of PKH26intensityrevealed a continuous gradient of cells, with PKH26retention ranging fromPKH26hi, PKH26low, to PKH26neg. PKH26hicells were suggestive of beingdormant or slow-cycling state, while PKH26lowcells were undergoing partiallabel dilution representative of limited divisions, and PKH26negcells indicatedrapid division. Such profiles could also be identified in SKOV3-R tumors.The percentage of each PKH26retention fraction varied betweenSKOV3-P and SKOV3-R tumors. The percentage of sorted PKH26hicells（7.57%） from SKOV3-R tumors were significantly higher than that fromSKOV3-P cells （2.89%, P=0.003）. Accordingly, the proportion of PKH26lowcells （70.94%） from SKOV3-R tumors was significantly higher than that fromSKOV3-P tumors （48.87%, P=0.002）, whereas PKH26negcells （20.58%） fromSKOV3-R tumors were significantly lower than that from SKOV3-P tumors（46.97%, P=0.002）. The elevated numbers of PKH26hicells from SKOV3-Rtumors supported the hypothesis that the administration of cisplatin led to theselection for the survival of dormant cells. 4Effects induced by cisplatin on the cell cycle distribution of ovariancancer cellsCell cycle control is an important aspect in CSC biology, and deregulatedcell cycle control is one of the fundamentally intrinsic steps contributing toCSC-derived tumorigenesis. To analyze the proliferative difference ofPKH26-labeled ovarian cancer cells between SKOV3-P and SKOV3-R tumors,the cell cycle distribution of every PKH26labeling intensity cell group wasevaluated by flow cytometry.We found that PKH26hicells in SKOV3-P and SKOV3-R tumors werealmost all arrested in the G0/G1phase, which further supported the fact thatPKH26hicells represent label-retaining, dormant or slow-cycling cells.PKH26lowcells in SKOV3-P tumors showed a higher fraction of cells inthe G0/G1phase. Compared with PKH26lowcells in SKOV3-P tumors, the Sphase fraction of PKH26lowcells in SKOV3-R tumors increased and the G2/Mphase fraction decreased （P=0.014and P=0.04, respectively）, which was amajor difference between PKH26lowcells in SKOV3-P tumors and those inSKOV3-R tumors. These data suggested that PKH26lowcells in SKOV3-Rtumors seemed to re-enter the cell cycle and develop chemotherapeuticresistance.PKH26negpopulations from SKOV3-P and SKOV3-R tumors wereenriched in S phase as compared with the PKH26lowpopulation （P=0.004andP=0.001, respectively）, which was in line with the characteristics of PKH26negcells, i.e. rapid cell division. In comparison to PKH26negcells from SKOV3-Ptumors, PKH26negcells in SKOV3-R tumors showed a decrease in the numberof cells in G0/G1and an increase in the number of cells in S phase and G2/Mphase （P=0.2, P=0.001and P=0.47, respectively）. Although chemotherapyresulted in a decrease in the G0/G1and G2/M phase fraction of PKH26negcellsfrom SKOV3-R tumors in comparison with that from SKOV3-P tumors, thedifference was not significant （P>0.05）.5Label-retaining PKH26hicells preferentially expressed stem cellmarkers and cisplatin enhanced their expression To explore whether PKH26hicells have intrinsic properties conferringstem-like characteristics, we investigated the expression of three markers thatare important in specific signaling pathways and are crucial in establishing andmaintaining stem-like characteristics.Real-time RT-PCR was employed to analyze the expression of stem cellmarkers in PKH26-labeled ovarian cancer cells from SKOV3-P andSKOV3-R tumors. SKOV3-P-PKH26hiand SKOV3-R-PKH26hicells allexpressed higher levels of Nestin, Oct3/4, and CD117than theSKOV3-P-PKH26lowand SKOV3-R-PKH26lowcells （P<0.05）, whereasPKH26negcells did not express the stem cell markers.The significant expression difference of stem cell markers existedbetween SKOV3-P-PKH26hiand SKOV3-R-PKH26hicells. Nestin, Oct3/4,and CD117mRNA were expressed in PKH26hicells from SKOV3-R tumorsmuch more highly than its countparters from SKOV3-P tumors （P=0.024,P=0.045, and P=0.022, respectively）.Meanwhile, flow cytometry was used to detect the protein expression ofstem cell markers in PKH26-labeled ovarian cancer cells from SKOV3-P andSKOV3-R tumors. PKH26hicells in SKOV3-P and SKOV3-R tumorsexpressed higher levels of Nestin, Oct3/4, and CD117than PKHlowcells inSKOV3-P and SKOV3-R tumors （P<0.05）, and PKH26negcells in SKOV3-Pand SKOV3-R tumors did not express the stem cell markers. Compared withSKOV3-P-PKH26hicells, SKOV3-R-PKH26hicells expressed significantlyhigher Nestin, Oct3/4, and CD117protein （P=0.04, P=0.037, and P=0.001,respectively）.6Label-retaining PKH26hicells exhibited colony formation capabilityand tumorigenicity and cisplatin increased stem-like featuresIn vitro, both PKH26hiand PKH26lowcells demonstrated clonogeniccapability and the clone formation rate of PKH26hicells was significantlyhigher than that of PKHlowcells in SKOV3-P tumors （t=11.029, P=0.001）.Similarly, the clone formation rate of PKH26hicells was significantly higherthan that of PKH26lowcells in SKOV3-R tumors （t=13.81, P=0.000）. The colony formation capability was almost absent in PKH26negcells derived fromSKOV3-P and SKOV3-R cells.There was a difference between the clonogenic capability of SKOV3-Pand SKOV3-R tumor cells and the clone formation rate of SKOV3-R-PKH26hicells was significantly higher than SKOV3-P-PKH26hicells （t=4.467,P=0.011）. A similar situation was observed in PKH26lowcells （t=4.35,P=0.012）.In vivo, we also probed the tumorigenicity of the three groups of screenedPKH26-retaining cells from SKOV3-P and SKOV3-R tumors. The PKH26hi,PKH26low, and PKH26negcells from SKOV3-P and SKOV3-R tumors wererespectively s.c. transplanted into5–6-week-old female nude mice at two celldensities （10,000cells/ml and20,000cells/ml）.In SKOV3-P tumors, PKH26hicells showed tumorigenicity at both celldensities, and tumorigenic rates were50%（3/6） and83%（5/6） respectively.PKH26lowand PKH26negcells failed to display tumorigenicity.In SKOV3-R tumor, the high tumorigenic nature of the PKH26hicellswas clearly shown at two cell densities was capable of developing tumors. Thetumorigenic rates were83%（5/6） and100%（6/6） respectively. The minimalcell density of tumor initiation for the PKH26hicells was20,000cells/ml andthe tumorigenic rate was33%（2/6）, whereas tumorigenicity was totally absentin the PKH26negcells at both cell densities injected.Although there was no statistically significant difference betweenSKOV3-P-PKH26hicells and SKOV3-R-PKH26hicells in the tumorigenic rate,SKOV3-R-PKH26hicells exhibited higher tumorigenicity tendency. A similarsituation was observed in PKH26lowcells at the cell density of20,000cells/ml（P>0.05）.Conclusions:1There may be multiple cell clones （PKH26hi, PKH26low, and PKH26negcells） in single cell line-generated xenograft tumors, and these cell clonesshow many different growth rates, cell cycle distributions and expressionprofiles of stem cell markers. 2PKH26hicells from SKOV3-P and SKOV3-R tumors weredormant/slow-cycling cells and exhibited stem cell properties.3Chemotherapy led to the enrichment of PKH26hicell clones andenhanced the stemness of SKOV3-R-PKH26hicell clones in mice xenograftmodel.Part2Insulin-like growth factor receptor signaling pathway modulatesproliferation of dormant cells in epithelial ovarian cancer xenograftsObjective: To explore the relationship between IGF receptor signalingpathway and the proliferation of dormant cancer stem cells in epithelialovarian cancer.Methods and meterials:In the present study, the stem-like PKH26hicells was sorted fromSKOV3-R tumors （i.e. SKOV3-R-PKH26hicells）.1Immunocytochemistry was used to observe the protein expression ofIGF-1, IGF-2and IGF-1R in SKOV3-R-PKH26hicells.2ELISA was used to evaluate the protein levels of IGF-1and IGF-2inthe medium of SKOV3-R-PKH26hicells.3Cell count and MTT assay were used to measure the proliferation ofSKOV3-R-PKH26hicells with different concentrations of IGF-1.4Flow cytometry was used to analyze the protein expression of IGF-1Rand Ki-67in SKOV3-R-PKH26hicells.5The expression of p-AKT, p-GSK3β and Cyclin B1ofSKOV3-R-PKH26hicells were determined by Western blotting.6Flow cytometry was used to study the cell cycle and apoptosis ofSKOV3-R-PKH26hicells.Results:1Expression of IGF-1, IGF-2and IGF-1R protein levels in theSKOV3-R-PKH26hicellsImmunocytochemical staining of SKOV3-R-PKH26hicells grown inserum-free conditions showed staining for IGF-1, IGF-2and IGF-1R.2Expression of IGF-1and IGF-2protein levels in the medium of SKOV3-R-PKH26hicellsMedium recovered from cells grown for24h in serum-free condition,revealed the presence of （49.91±1.24） ng/ml IGF-1protein and （93.21±2.35）ng/ml IGF-2protein by ELISA. Following48h under the same conditions, thelevel of IGF-1increased to （78.29±1.02） ng/ml and IGF-2increased to（160.39±1.88） ng/ml. The level of IGF-1increased to （105.92±6.09） ng/mland IGF-2increased to （190.52±3.17） ng/ml in serum-free condition after72h,and the level of IGF-1and IGF-2significantly higher than that in24h and48h.3The proliferation of SKOV3-R-PKH26hicells with differentconcentrations of IGF-1Cell count and MTT assays showed that we incubated theSKOV3-R-PKH26hicells with IGF-1and could detect impact on cellularproliferation at lower concentration. IGF-1increased the proliferation ofSKOV3-R-PKH26hicells in a dose-dependent manner.4The protein expression of IGF-1R and Ki-67in SKOV3-R-PKH26hicellsFlow cytometry result showed that the protein expression of IGF-1R andKi-67in SKOV3-R-PKH26hicells was increased with prolonged incubationtime （P<0.01）。5Detection of PI3K/AKT signaling pathwayWestern blot was conducted and a time-dependent increase in p-AKT andp-GSK3β expression was observed.6The protein expression of Cyclin B1in SKOV3-R-PKH26hicellsWestern blot showed that the protein expression of Cyclin B1after48hand72h were significantly higher than that after24h （P<0.05）. Althoughthere was no statistically significant difference in the protein expression ofCyclin B1between the48h and72h, the protein expression of Cyclin B1after72h exhibited higher tendency.7The cell cycle and apoptosis of SKOV3-R-PKH26hicells was analyzedby flow cytometry With prolonging culture time, SKOV3-R-PKH26hicells showed areduction of cells in the G0/G1and G2/M phase （P<0.05）, and accumulationof cells in S phases （P<0.05）.The apoptotic rates of SKOV3-R-PKH26hicells were （0.233±0.25）%,（0.253±0.30）%and （0.247±0.15）%respectively, and the apoptotic rates indifferent culture time were no significant difference （P>0.05）.Conclusions:1IGF-1, IGF-2and IGF-1R are present on the SKOV3-R-PKH26hicells,and the level of IGF-1and IGF-2and the expression of IGF-1R weresignificantly increased with prolonged incubation time. It suggests that IGFautocrine loop was existed in SKOV3-R-PKH26hicells.2PI3K/AKT signaling pathway activated by the IGF-1R could stimulatethe proliferation and reduce the apoptosis of SKOV3-R-PKH26hicells throughthe up-regulation of Cyclin B1expression and conversion of the G2/M phase.It indicates that insulin-like growth factor receptor signaling pathway couldmodulate proliferation of dormant cancer stem cells in epithelial ovariancancer.Part3Inhibiting insulin-like growth factor receptor signaling pathway tosuppresses proliferation of dormant cells in epithelial ovarian cancerxenograftsObjective: To observe the effect of the inhibition of IGF receptorsignaling pathway on the proliferation and apoptosis in dormant cells ofepithelial ovarian cancer xenografts.Methods and meterials:In the present study, the stem-like PKH26hicells was sorted fromSKOV3-R tumors （i.e. SKOV3-R-PKH26hicells）.1MTT assay was used to measure the proliferation inhibition of theSKOV3-R-PKH26hicells with different concentrations of NVP.2MTT assay was used to measure the proliferation inhibition ofSKOV3-R-PKH26hicells with NVP combined with IGF-1R.3Flow cytometry was used to measure the effect on protein expres sion of IGF-1R and Ki-67of SKOV3-R-PKH26hicells by NVP.4Flow cytometry was used to study the effect on cell cycle and apoptosis of SKOV3-R-PKH26hicells by NVP.5MTT assay was used to measure the proliferation inhibition ofSKOV3-R-PKH26hicells with NVP combined with different concentrations ofDDP.6Effect of NVP on the expression of related protein in PI3K/AKTsignaling pathway was determined by Western blotting.7Clonogenicity assay was performed to determine the effect on cloneformation rate of SKOV3-R-PKH26hicells by NVP.8Tumorigenicity assay was performed to determine the tumorigenicity ofSKOV3-R-PKH26hicells by NVP.Results:1The inhibition effect of NVP on the SKOV3-R-PKH26hicells wasdetermined by MTT assaysSKOV3-R-PKH26hicells plated and exposed in serum-free conditions fordifferent time and increasing doses of NVP showed a time-dependent increasein toxicity and a dose-dependent reduction in surviving cells. NVP inhibits theproliferation of SKOV3-R-PKH26hicells in a dose-and time-dependentmanner. SKOV3-R-PKH26hicells exposed in15μM NVP showed the highestinhibition, so we chose15μM for subsequent experiment.2The inhibition effect of NVP with IGF-1on the SKOV3-R-PKH26hicellsMonolayers of cells were exposed to increasing doses of NVP inconjunction with40ng/ml of IGF-1. Viability was assessed using MTT assay.The result showed that add back of40ng/ml of IGF-1did not revert the NVPinduced inhibition of proliferation.3NVP inhibits the protein expression of IGF-1R and Ki-67inSKOV3-R-PKH26hicellsFlow cytometry result showed that the protein expression of IGF-1R andKi-67in SKOV3-R-PKHhicells increased significantly than that in control group（P<0.05）。4Induction of cell cycle distribution and apoptosis by NVPNVP could inhibit the proliferation of SKOV3-R-PKH26hicells. Flowcytometry analysis showed that NVP caused a reduction of cells in the G0/G1phase （P<0.05）, and accumulation of cells in S and G2/M phases （P<0.05）.IGF-1R activation has been shown to protect cells from apoptosis.Interference with this mechanism by the IGF-1R inhibitor could explain thecell death observed in the cytotoxicity experiments. For these reasons, weinvestigated whether SKOV3-R-PKH26hicells exposed to NVP underwentapoptosis. SKOV3-R-PKH26hicells exposed to15μM NVP for48h resultedin an increase in the proportion of apoptotic cells compared with control group（17.44±1.14%vs.0.25±1.76%，P<0.01）.5NVP inhibits the proliferation of SKOV3-R-PKH26hicells andpotentiates the effect of DDPIn order to evaluate whether NVP could increase the toxicity of DDP onSKOV3-R-PKH26hicells, co-incubation experiments using increasing doses ofDDP with NVP were performed. At each dose of DDP, the addition of NVPdecreases the number of surviving cells （P<0.05）.6Effect of NVP on the inactivation of PI3K/AKT pathwayWestern blot showed that NVP notably reduced protein expressions ofphosphor-AKT （p-AKT）, the activated form of AKT and its downstreamtargets including phosphor-GSK3β （p-GSK3β）, Cyclin B1, Bcl-xL （P<0.05）,and increased protein expression of Bax （P<0.05）, but not that of total level ofAKT and GSK3β （P>0.05） in SKOV3-R-PKH26hicells.7Effects of NVP on the colony forming capability ofSKOV3-R-PKH26hicellsNVP could inhibit the colony forming capability of SKOV3-R-PKH26hicells. Colony formation assay showed the clone formation rate of NVP groupwas significantly lower than that of control group （23.6±2.3%vs.42.2±1.8%,P<0.05）.8NVP significantly suppresses xenograft growth in nude mice Considering the above in vitro showing that NVP reduced theproliferation of SKOV3-R-PKH26hicells, it will be crucial to evaluate whetherNVP could inhibit tumorigenicity of SKOV3-R-PKH26hicells in vivo.Nude mice with established s.c tumor xenograft fromSKOV3-R-PKH26hicells was employed and treated with oral administrationof NVP. The tumorigenic rate of control group was100%（6/6）, whereas thetumorigenic rate of NVP-treated group was16.7%（1/6）. NVP-treated groupexhibited significantly lower tumorigenicity compared with control group（P<0.05）.Nude mice of NVP-treated group were in good condition and were notassociated with side effects. There was no significant difference in the bodyweight of nude mice between the two groups （19.95±0.99g for NVP-treatedgroup vs.20.6±0.86g for control group, P>0.05）.No significant toxic effects were found by observing the histology ofheart, liver, lung, and intestine in the NVP-treated mice.Conclusions:1IGF-1R kinase inhibitor NVP can suppress the proliferation andincrease the rate of paoptosis and the sensitivity of cisplain in theSKOV3-R-PKH26hicells. It indicates that inhibiting IGF-1R could suppressthe proliferation and increase apoptasis and sensitivity of cisplatin in dormantcells mediated by inhibition of PI3K/AKT signaling pathway.2NVP could significantly inhibit colony forming capability and thetumorigenicity of SKOV3-R-PKH26hicells. It suggests that IGF-1R plays animportant role in modulating the proliferation of dormant cells. |
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