The doublecortin (DCX) gene encodes DCX, a microtubule-associated protein that plays a crucial role in brain development. DCX variants can disrupt microtubule binding and stabilization, interfere with intracellular transport, and affect post-translational modifications. A correlation exists between variant types and clinical severity. Animal models and induced pluripotent stem cell (iPSC) models simulating DCX deficiency revealed the dynamic progression of the disease, which has provided a powerful tool for investigating disease mechanisms and screening therapeutic agents. Currently there is no cure for DCX variants, with treatment primarily relying on anti-epileptic drugs and symptom management. Basic research is now offering new avenues for future therapeutic approaches. This article has summarized the potential pathogenic mechanisms and therapeutic strategies for the DCX variants, with an aim to provide insights for clinical treatment.
Humans ; Doublecortin Protein ; Doublecortin Domain Proteins ; Animals ; Neuropeptides/metabolism* ; Microtubule-Associated Proteins/metabolism* ; Mutation

Objective:To investigate the correlation between carotid-femoral pulse wave velocity(cfPWV)and carotid artery structural,hemodynamic,and cardiac functional parameters.Methods:A total of 420 healthy volunteers who underwent neck ultrasound,cardiac ultrasound,and cfPWV examination at Kailuan General Hospital from June 2022 to February 2023 were selected,and they were divided into two groups based on the atherosclerosis threshold value of cfPWV>10 m/s,which included high cfPWV group(140 cases,cfPWV>10 m/s)and low cfPWV group(280 cases,cfPWV≤10 m/s).The demographic data(age,sex)of 420 persons were collected,and the common carotid artery diameter(CCAD),common carotid artery intima-media thickness(CIMT),plaque status,peak systolic velocity(PSV),end-diastolic velocity(EDV)and mean flow velocity(MFV)were compared between two groups.Then,the differences of interventricular septal thickness(IVST)of heart,left ventricular posterior wall thickness(LVPWT),the ratio of blood flow velocity at early stage to that at advanced stage in mitral valve(E/A)and stroke volume(SV)were analyzed.Multivariate logistic regression was adopted to analyze the independent influence factors of cfPWV enhancement.Results:The average age of high cfPWV group was(61.31±9.66)years old,which was significantly higher than(51.06±10.47)years old of low cfPWV group,and the difference of that was significant(t=-9.56,P<0.01).In the parameters of common carotid artery,63 persons(45.0%)occurred plaque in 140 persons of high cfPWV group,which was significantly lower than 50 persons(17.86%)in 280 persons of low cfPWV group,and the difference of that between two groups was significant(x2=34.97,P<0.05).The differences of CCAD,CIMT,PSV,EDV and MV of common carotid artery at right side of persons between two groups were significant(t=-2.16,-5.40,4.52,5.59,5.04,P<0.05),respectively.The parameters of heart showed that the LVPWT thickness increased(9.35±1.13)mm,and the ratio of E/A<1 increased 77.86%in high cfPWV group,which were significantly related to the increase of cfPWV(r=0.27,0.38,P<0.01).Multivariate logistic regression analysis indicated that age(OR=1.05,95%CI:1.02-1.08),CCAD(OR=1.63,95%CI:1.22-2.16),plaque presence(OR=1.84,95%CI:1.07-3.17),LVPWT(OR=1.35,95%CI:1.05-1.72),and the ratio of E/A<1(OR=2.37,95%CI:1.32-4.26)were independent predictors of cfPWV enhancement.Conclusion:The enhancement of cfPWV is closely related to high age,the reconstruction of common carotid artery(widening of inside diameter,and plaque formation),left ventricular hypertrophy,and diastolic abnormality,which indicates it is possible that atherosclerosis process accompanies by the change of interaction mechanism of blood vessels-heart.

BACKGROUND:The proliferation and phenotypic maintenance of chondrocytes are limited under two-dimensional culture conditions.Porous microspheres serve as scaffolds,providing a three-dimensional culture environment that better mimics in vivo growth conditions.Stromal cell derived factor-1,a homeostatic cytokine with potent chemotactic effects,facilitates cell adhesion and proliferation.OBJECTIVE:To investigate the impact of stromal cell derived factor-1 grafted poly-L-lactic acid porous microspheres on the biological characteristics of chondrocytes and the formation of cartilage tissue.METHODS:(1)The effects of different concentrations of stromal cell derived factor-1 on rabbit chondrocyte proliferation,migration,and phenotypic maintenance were investigated in an in vitro setting.(2)Poly-L-lactic acid porous microspheres were prepared by double emulsion method.Stromal cell derived factor-1 was grafted onto poly-L-lactic acid porous microspheres through carbodiimide reaction.The grafting was verified by enzyme-linked immunosorbent assay and incubation with stromal cell derived factor-1-specific fluorescent antibodies.(3)Rabbit chondrocytes were inoculated on poly-L-lactic acid porous microspheres and grafted on stromal cell derived factor-1 poly-L-lactic acid porous microspheres to detect cell proliferation and adhesion.(4)The methylacrylamide-gelatin-chondrocyte complex(control group),poly-L-lactic acid porous microsphere-methylacrylamide-gelatin-chondrocyte complex(porous microsphere group),and grafted stromal cell derived factor-1 poly-L-lactic acid porous microsphere-methylacrylamide-gelatin-chondrocyte complex(porous microsphere modified group)were implanted under the skin of the back of nude mice,respectively.Samples were collected 8 weeks later and detected using histological staining and qRT-PCR for chondroblast related genes.RESULTS AND CONCLUSION:(1)Compared with 0 and 1 000 ng/mL stromal cell derived factor-1,1 and 500 ng/mL stromal cell derived factor 1 could promote the proliferation and migration of chondrocytes,and enhance the mRNA expression levels of type Ⅱ collagen,elastin,proliferating cell nuclear antigen,and Bcl-2 in chondrocytes.(2)Stromal cell derived factor-1 was successfully grafted onto poly-L-lactic acid porous microspheres with a grafting rate of 93.75%.(3)Compared with poly-L-lactic acid porous microspheres,grafted stromal cell derived factor-1 poly-L-lactic acid porous microspheres promoted the proliferation and adhesion of chondrocytes.(4)After 8 weeks of subcutaneous implantation in nude mice,compared with the control group and the porous microsphere group,the porous microsphere modified group had clearer cartilage lacunae structure,more chondro-specific matrix and type Ⅱ collagen deposition,and increased expression of elastin,type Ⅱ collagen,proliferating cell nuclear antigen,and Bcl-2 mRNA.These findings indicate that stromal cell derived factor-1 grafted poly-L-lactic acid porous microspheres are beneficial to chondrocyte adhesion,proliferation,phenotypic maintenance,and the formation of cartilage tissue in vivo.

Objective:To elucidate the regulatory role of matrix metallopeptidase 14 (MMP14) in the migration of chondrogenic precursor cells, thereby providing data support for investigating the pathogenesis of microtia.Methods:An in vitro differentiation model was established using human induced pluripotent stem cells (iPSCs) sequentially induced into neural crest cells (iNCCs) and subsequently into chondrogenic precursor cells (iCPCs), combined with lentivirus-mediated knockdown of MMP14, to investigate the effects of MMP14 on the biological characteristics of iCPCs, including proliferation, differentiation, and migration. Collective cell migration was assessed using scratch wound healing and Transwell migration assays; directional migration was characterized via high-content live-cell imaging; single-cell adhesion force was measured using a micromanipulation system. Collagen degradation was evaluated through hydroxyproline digestion assays. Cell proliferation was analyzed using the CCK-8 assay, and the expression of osteogenic/chondrogenic-related genes (SOX5/6/9, COL1A1, COL2A1, RUNX2, TWIST1) were quantified by real-time quantitative PCR. Immunofluorescence staining was used to assess the expression of F-actin and CD44 proteins. Additionally, transcriptomic sequencing was performed on iCPCs before and after MMP14 knockdown. Results:iPSC→iNCC→iCPC differentiation model was established in vitro. The resulting iCPCs expressed osteo/chondrogenic marker genes, including SOX5, SOX6, SOX9, COL1A1, COL2A1, RUNX2, and TWIST1, and exhibited positive expression of mesenchymal stem cell markers CD90, CD105, and CD73. Upon further induction, functional cartilage spheroids were formed. Compared with normal auricular chondrocytes, auricular chondrocytes from microtia patients showed reduced expression of MMP14 at both mRNA and protein levels. Lentivirus-mediated shRNA knockdown of MMP14 in iCPCs resulted in a marked decrease in its mRNA and protein expression. MMP14 knockdown significantly impaired collective migration of iCPCs, as evidenced by reduced wound closure rates in scratch assays and decreased numbers of migrated cells in Transwell assays. High-content live-cell imaging revealed that MMP14-deficient iCPCs displayed more erratic migration trajectories and a lower straight-line migration ratio. Single-cell adhesion assays showed extracellular matrix (ECM)-dependent alterations: cell adhesion was enhanced on matrigel-coated surfaces but weakened under uncoated conditions. MMP14 knockdown also led to reduced proliferation, decreased collagen degradation, diminished F-actin expression, fewer peripheral adhesion sites, and downregulation of CD44 protein expression, without significantly affecting the expression of chondrogenic genes such as SOX6, SOX9, COL1A1, COL2A1, RUNX2, and TWIST1. Transcriptomic analysis further revealed that MMP14 knockdown significantly downregulated genes involved in extracellular matrix organization, cell adhesion, migration, and tissue development, with enrichment in pathways including ECM-receptor interaction, focal adhesion, and MAPK signaling. Conclusion:MMP14 plays a critical role in the directional migration of chondrogenic precursor cells by regulating ECM remodeling, adhesion signaling, and cytoskeletal proteins.

BACKGROUND: Postoperative pulmonary complications (PPCs) are major adverse events in neurosurgical patients. This study aimed to develop and validate machine learning models predicting PPCs after neurosurgery. METHODS: PPCs were defined according to the European Perioperative Clinical Outcome standards as occurring within 7 postoperative days. Data of cases meeting inclusion/exclusion criteria were extracted from the anesthesia information management system to create three datasets: The development (data of Huashan Hospital, Fudan University from 2018 to 2020), temporal validation (data of Huashan Hospital, Fudan University in 2021) and external validation (data of other three hospitals in 2023) datasets. Machine learning models of six algorithms were trained using either 35 retrievable and plausible features or the 11 features selected by Lasso regression. Temporal validation was conducted for all models and the 11-feature models were also externally validated. Independent risk factors were identified and feature importance in top models was analyzed. RESULTS: PPCs occurred in 712 of 7533 (9.5%), 258 of 2824 (9.1%), and 207 of 2300 (9.0%) patients in the development, temporal validation and external validation datasets, respectively. During cross-validation training, all models except Bayes demonstrated good discrimination with an area under the receiver operating characteristic curve (AUC) of 0.840. In temporal validation of full-feature models, deep neural network (DNN) performed the best with an AUC of 0.835 (95% confidence interval [CI]: 0.805-0.858) and a Brier score of 0.069, followed by Logistic regression (LR), random forest and XGBoost. The 11-feature models performed comparable to full-feature models with very close but statistically significantly lower AUCs, with the top models of DNN and LR in temporal and external validations. An 11-feature nomogram was drawn based on the LR algorithm and it outperformed the minimally modified Assess respiratory RIsk in Surgical patients in CATalonia (ARISCAT) and Laparoscopic Surgery Video Educational Guidelines (LAS VEGAS) scores with a higher AUC (LR: 0.824, ARISCAT: 0.672, LAS: 0.663). Independent risk factors based on multivariate LR mostly overlapped with Lasso-selected features, but lacked consistency with the important features using the Shapley additive explanation (SHAP) method of the LR model. CONCLUSIONS: The developed models, especially the DNN model and the nomogram, had good discrimination and calibration, and could be used for predicting PPCs in neurosurgical patients. The establishment of machine learning models and the ascertainment of risk factors might assist clinical decision support for improving surgical outcomes. TRIAL REGISTRATION ChiCTR 2100047474; https://www.chictr.org.cn/showproj.html?proj=128279 .
Adult ; Aged ; Female ; Humans ; Male ; Middle Aged ; Algorithms ; Lung Diseases/etiology* ; Machine Learning ; Neurosurgical Procedures/adverse effects* ; Postoperative Complications/diagnosis* ; Risk Factors ; ROC Curve

Objective:To elucidate the regulatory role of matrix metallopeptidase 14 (MMP14) in the migration of chondrogenic precursor cells, thereby providing data support for investigating the pathogenesis of microtia.Methods:An in vitro differentiation model was established using human induced pluripotent stem cells (iPSCs) sequentially induced into neural crest cells (iNCCs) and subsequently into chondrogenic precursor cells (iCPCs), combined with lentivirus-mediated knockdown of MMP14, to investigate the effects of MMP14 on the biological characteristics of iCPCs, including proliferation, differentiation, and migration. Collective cell migration was assessed using scratch wound healing and Transwell migration assays; directional migration was characterized via high-content live-cell imaging; single-cell adhesion force was measured using a micromanipulation system. Collagen degradation was evaluated through hydroxyproline digestion assays. Cell proliferation was analyzed using the CCK-8 assay, and the expression of osteogenic/chondrogenic-related genes (SOX5/6/9, COL1A1, COL2A1, RUNX2, TWIST1) were quantified by real-time quantitative PCR. Immunofluorescence staining was used to assess the expression of F-actin and CD44 proteins. Additionally, transcriptomic sequencing was performed on iCPCs before and after MMP14 knockdown. Results:iPSC→iNCC→iCPC differentiation model was established in vitro. The resulting iCPCs expressed osteo/chondrogenic marker genes, including SOX5, SOX6, SOX9, COL1A1, COL2A1, RUNX2, and TWIST1, and exhibited positive expression of mesenchymal stem cell markers CD90, CD105, and CD73. Upon further induction, functional cartilage spheroids were formed. Compared with normal auricular chondrocytes, auricular chondrocytes from microtia patients showed reduced expression of MMP14 at both mRNA and protein levels. Lentivirus-mediated shRNA knockdown of MMP14 in iCPCs resulted in a marked decrease in its mRNA and protein expression. MMP14 knockdown significantly impaired collective migration of iCPCs, as evidenced by reduced wound closure rates in scratch assays and decreased numbers of migrated cells in Transwell assays. High-content live-cell imaging revealed that MMP14-deficient iCPCs displayed more erratic migration trajectories and a lower straight-line migration ratio. Single-cell adhesion assays showed extracellular matrix (ECM)-dependent alterations: cell adhesion was enhanced on matrigel-coated surfaces but weakened under uncoated conditions. MMP14 knockdown also led to reduced proliferation, decreased collagen degradation, diminished F-actin expression, fewer peripheral adhesion sites, and downregulation of CD44 protein expression, without significantly affecting the expression of chondrogenic genes such as SOX6, SOX9, COL1A1, COL2A1, RUNX2, and TWIST1. Transcriptomic analysis further revealed that MMP14 knockdown significantly downregulated genes involved in extracellular matrix organization, cell adhesion, migration, and tissue development, with enrichment in pathways including ECM-receptor interaction, focal adhesion, and MAPK signaling. Conclusion:MMP14 plays a critical role in the directional migration of chondrogenic precursor cells by regulating ECM remodeling, adhesion signaling, and cytoskeletal proteins.

BACKGROUND:The proliferation and phenotypic maintenance of chondrocytes are limited under two-dimensional culture conditions.Porous microspheres serve as scaffolds,providing a three-dimensional culture environment that better mimics in vivo growth conditions.Stromal cell derived factor-1,a homeostatic cytokine with potent chemotactic effects,facilitates cell adhesion and proliferation.OBJECTIVE:To investigate the impact of stromal cell derived factor-1 grafted poly-L-lactic acid porous microspheres on the biological characteristics of chondrocytes and the formation of cartilage tissue.METHODS:(1)The effects of different concentrations of stromal cell derived factor-1 on rabbit chondrocyte proliferation,migration,and phenotypic maintenance were investigated in an in vitro setting.(2)Poly-L-lactic acid porous microspheres were prepared by double emulsion method.Stromal cell derived factor-1 was grafted onto poly-L-lactic acid porous microspheres through carbodiimide reaction.The grafting was verified by enzyme-linked immunosorbent assay and incubation with stromal cell derived factor-1-specific fluorescent antibodies.(3)Rabbit chondrocytes were inoculated on poly-L-lactic acid porous microspheres and grafted on stromal cell derived factor-1 poly-L-lactic acid porous microspheres to detect cell proliferation and adhesion.(4)The methylacrylamide-gelatin-chondrocyte complex(control group),poly-L-lactic acid porous microsphere-methylacrylamide-gelatin-chondrocyte complex(porous microsphere group),and grafted stromal cell derived factor-1 poly-L-lactic acid porous microsphere-methylacrylamide-gelatin-chondrocyte complex(porous microsphere modified group)were implanted under the skin of the back of nude mice,respectively.Samples were collected 8 weeks later and detected using histological staining and qRT-PCR for chondroblast related genes.RESULTS AND CONCLUSION:(1)Compared with 0 and 1 000 ng/mL stromal cell derived factor-1,1 and 500 ng/mL stromal cell derived factor 1 could promote the proliferation and migration of chondrocytes,and enhance the mRNA expression levels of type Ⅱ collagen,elastin,proliferating cell nuclear antigen,and Bcl-2 in chondrocytes.(2)Stromal cell derived factor-1 was successfully grafted onto poly-L-lactic acid porous microspheres with a grafting rate of 93.75%.(3)Compared with poly-L-lactic acid porous microspheres,grafted stromal cell derived factor-1 poly-L-lactic acid porous microspheres promoted the proliferation and adhesion of chondrocytes.(4)After 8 weeks of subcutaneous implantation in nude mice,compared with the control group and the porous microsphere group,the porous microsphere modified group had clearer cartilage lacunae structure,more chondro-specific matrix and type Ⅱ collagen deposition,and increased expression of elastin,type Ⅱ collagen,proliferating cell nuclear antigen,and Bcl-2 mRNA.These findings indicate that stromal cell derived factor-1 grafted poly-L-lactic acid porous microspheres are beneficial to chondrocyte adhesion,proliferation,phenotypic maintenance,and the formation of cartilage tissue in vivo.

Objective:To investigate the correlation between carotid-femoral pulse wave velocity(cfPWV)and carotid artery structural,hemodynamic,and cardiac functional parameters.Methods:A total of 420 healthy volunteers who underwent neck ultrasound,cardiac ultrasound,and cfPWV examination at Kailuan General Hospital from June 2022 to February 2023 were selected,and they were divided into two groups based on the atherosclerosis threshold value of cfPWV>10 m/s,which included high cfPWV group(140 cases,cfPWV>10 m/s)and low cfPWV group(280 cases,cfPWV≤10 m/s).The demographic data(age,sex)of 420 persons were collected,and the common carotid artery diameter(CCAD),common carotid artery intima-media thickness(CIMT),plaque status,peak systolic velocity(PSV),end-diastolic velocity(EDV)and mean flow velocity(MFV)were compared between two groups.Then,the differences of interventricular septal thickness(IVST)of heart,left ventricular posterior wall thickness(LVPWT),the ratio of blood flow velocity at early stage to that at advanced stage in mitral valve(E/A)and stroke volume(SV)were analyzed.Multivariate logistic regression was adopted to analyze the independent influence factors of cfPWV enhancement.Results:The average age of high cfPWV group was(61.31±9.66)years old,which was significantly higher than(51.06±10.47)years old of low cfPWV group,and the difference of that was significant(t=-9.56,P<0.01).In the parameters of common carotid artery,63 persons(45.0%)occurred plaque in 140 persons of high cfPWV group,which was significantly lower than 50 persons(17.86%)in 280 persons of low cfPWV group,and the difference of that between two groups was significant(x2=34.97,P<0.05).The differences of CCAD,CIMT,PSV,EDV and MV of common carotid artery at right side of persons between two groups were significant(t=-2.16,-5.40,4.52,5.59,5.04,P<0.05),respectively.The parameters of heart showed that the LVPWT thickness increased(9.35±1.13)mm,and the ratio of E/A<1 increased 77.86%in high cfPWV group,which were significantly related to the increase of cfPWV(r=0.27,0.38,P<0.01).Multivariate logistic regression analysis indicated that age(OR=1.05,95%CI:1.02-1.08),CCAD(OR=1.63,95%CI:1.22-2.16),plaque presence(OR=1.84,95%CI:1.07-3.17),LVPWT(OR=1.35,95%CI:1.05-1.72),and the ratio of E/A<1(OR=2.37,95%CI:1.32-4.26)were independent predictors of cfPWV enhancement.Conclusion:The enhancement of cfPWV is closely related to high age,the reconstruction of common carotid artery(widening of inside diameter,and plaque formation),left ventricular hypertrophy,and diastolic abnormality,which indicates it is possible that atherosclerosis process accompanies by the change of interaction mechanism of blood vessels-heart.

ObjectiveTo identify factors related to the occurrence of choking and coughing while eating in the disabled elderly and conduct importance matrix analysis to provide a reference basis for controlling choking on food in the disabled elderly. MethodsA convenience sampling method was used to select 80 disabled elderly individuals in a hospital between October 2019 and April 2022 as the study population. The occurrence of choking and coughing while eating was recorded， and a questionnaire was administered to collect general information. Additionally， assessments were conducted using the intelligent mental status examination scale （MMSE）， oral health checklist （BOHSE）， eating assessment tool⁃10 （EAT-10）， and chewing function evaluations. Univariate and multifactorial analyses were conducted to analyze the influencing factors of choking and coughing while eating in the elderly with disabilities. ResultsThe incidence of choking and coughing while eating was 52.50% （42/80） among the 80 disabled elderly. The degree of disability （OR=2.895， 95%CI： 1.352‒6.201）， age （OR=4.040， 95%CI： 1.121‒14.562）， BOHSE score （OR=2.473， 95%CI： 1.002‒6.102）， EAT-10 score （OR=5.345， 95%CI： 2.112‒13.527）， and chewing function score （OR=3.453， 95%CI： 1.247‒9.562） were identified as risk factors for choking and coughing while eating in the disabled elderly. The MMSE score （OR=0.343， 95%CI： 0.135‒0.869） was identified as a protective factor. The importance matrix analysis indicated that EAT-10 score， MMSE score， and chewing function had high importance with slightly lower difficulty in improvement， and were thus listed as items in the priority improvement area. Age and degree of disability had high importance and high difficulty in improvement， and therefore belonged to the suboptimal improvement area. BOHS score was slightly lower both in importance and difficulty of improvement， entering the alternative improvement area. ConclusionAge， degree of disability， BOHSE score， EAT-10 score， and chewing function score are risk factors for the occurrence of choking and coughing while eating， while the MMSE score is a protective factor. The importance matrix analysis can provide a basis for targeted intervention in clinical practice.

OBJECTIVES: To investigate the synergistic inhibitory effects of AKBA and doxorubicin on malignant phenotype of triple-negative breast cancer (TNBC) MDA-MB-231 cells. METHODS: CCK-8 assay was used to determine the 48-h IC₅₀ of AKBA and doxorubicin in MDA-MB-231 cells, and SynergyFinder was employed to calculate the synergistic index and the optimal concentrations of the two agents. MDA-MB-231 cells treated with AKBA (22.5 μmol/L), doxorubicin (0.84 μmol/L) or their combination were examined for changes in cell proliferation, migration, invasion and apoptosis using Transwell migration, scratch assay, clone generation, RT-qPCR and Western blotting. Network pharmacology analysis was conducted to identify the downstream targets of AKBA in TNBC. In nude mouse models bearing subcutaneous MDA-MB-231 cell xenografts, the effects of normal saline, AKBA (50 mg/kg), doxorubicin (2.5 mg/kg), and AKBA combined with doxorubicin on xenograft growth and histopathology were observed. RESULTS: The IC₅₀ of AKBA and doxorubicin in MDA-MB-231 cells at 48 h was 45.15±0.97 μmol/L and 0.42±0.99 μmol/L, respectively. SynergyFinder confirmed the synergistic effect of AKBA and ADR with a ZIP>10. The combined treatment with AKBA and doxorubicin significantly inhibited the proliferation, migration and invasion, promoted apoptosis of MDA-MB-231 cells, and effectively suppressed xenograft growth in nude mice. Network pharmacology analysis predicted that AKBA affects the progression of TNBC through its downstream target AKBA. CONCLUSIONS AKBA combined with doxorubicin inhibits proliferation, migration and invasion, promotes apoptosis of MDA-MB-231 cells and suppresses MDA-MB-231 cell xenograft growth in nude mice. The combined use of AKBA can attenuate the toxic effects of doxorubicin in nude mice.
Animals ; Doxorubicin/pharmacology* ; Triple Negative Breast Neoplasms/pathology* ; Mice, Nude ; Mice ; Cell Proliferation/drug effects* ; Cell Line, Tumor ; Humans ; Female ; Apoptosis/drug effects* ; Cell Movement/drug effects* ; Xenograft Model Antitumor Assays ; Drug Synergism ; MDA-MB-231 Cells