Analysis of free cisplatin in microdialysates and plasma ultrafiltrate by liquid chromatography-tandem mass spectrometry.

Cisplatin is a potent cytotoxic agent used in the treatment of various malignancies and exerts its antitumor effect through malignant cell DNA damage and apoptosis induction. Evaluation of systemic delivery of cisplatin is important in optimization of cisplatin treatment. However, accurate quantification of systemic cisplatin is challenging due to its various forms in circulation. This study aimed to develop a sensitive (LOQ < 0.1 µg/mL) and precise Ultra Performance Liquid Chromatography (UPLC) - Tandem Mass Spectrometry (MS/MS) method for quantifying free cisplatin in microdialysates and plasma. Furthermore the aim was to compare free cisplatin concentrations measured in standard plasma samples with those obtained from intravenous microdialysis catheters in a porcine model. The method developed utilizes dichloro(ethylenediamine)platinum(II) as an internal standard that co-elutes with cisplatin, ensuring precise correction for ion suppression/enhancement effects. The method was validated, demonstrating linearity up to 100 µg/mL and good intermediate precision (CV% < 6 %) in the range of 1.0-100 µg/mL, with an LOQ of 0.03 µg/mL. The pharmacokinetic parameters (AUC0-last, Cmax, T1/2, and Tmax) showed no significant differences between the two sampling methods. This validated LC-MS/MS method provides a reliable tool for quantifying systemic free cisplatin concentrations, facilitating future systemic and local pharmacokinetic evaluations for optimization of cisplatin-based cancer treatments.

Study on the Use of Ozone Water as a Chemical Decontamination Agent for Antineoplastic Drugs in Clinical Settings.

The exposure of healthcare workers to antineoplastic drugs in hospitals has been recognized to be harmful. To minimize the risk of exposure, the removal of these drugs from work environments, such as compounding facilities, has been recommended. In our previous paper, the degradation and inactivation efficacy of ozone water, which is being introduced into Japanese hospitals as a chemical decontamination agent, was reported for its effects on typical antineoplastic drugs (gemcitabine, irinotecan, paclitaxel). This article aims to further investigate the efficacy of ozone water for eight antineoplastic drugs to clarify its application limitations. A small amount (medicinal ingredient: typically ca. 1.5 µmol) of formulation containing 5-fluorouracil, pemetrexed, cisplatin, oxaliplatin, cyclophosphamide, ifosfamide, doxorubicin, or docetaxel was mixed with 50 mL of ozone water (~8 mg/L), and the resulting solutions were analyzed by high-performance liquid chromatography over time to observe the degradation. Consequently, the ozonation was overall effective for the degradation of the drugs, however this varied depending on the chemical structures of the drugs and additives in their formulations. In addition, after the parent drugs were completely degraded by the ozonation, the degradation mixtures were subjected to 1H nuclear magnetic resonance spectroscopy and evaluated for mutagenicity against Salmonella typhimurium strains and cytotoxicity against human cancer cells. The degradation mixtures of cisplatin and ifosfamide were mutagenic while those of the other drugs were non-mutagenic. Further, the ozonation resulted in clear decreases of cytotoxicity for 5-fluorouracil, oxaliplatin, and doxorubicin, but increases of cytotoxicity for pemetrexed, cisplatin, cyclophosphamide, and ifosfamide. These results suggest that the ozone water should be restrictedly used according to the situation of contamination in clinical settings because the ozonation enhances toxicity depending on the drug even if degradation is achieved.

Effect of cashew (Anacardium occidentale L.) nut-supplemented diet on steroidogenic enzymes, hormonal and oxidative imbalances, and sperm parameters in cisplatin-induced reproductive toxicity in male rats.

Cisplatin (CP) is a chemotherapeutic/anticancer drug culpable in sperm and testicular damage, but the use of dietary patterns has been reported to averse this effect. To date, no report on the use of roasted cashew nut-supplemented diets (RCNSD) against chemotherapy-induced testicular damage has been presented. In this study, the effect of 10% and 20% RCNSD on reproductive hormones, sperm parameters, testicular and epididymal antioxidant status, and steroidogenic enzymes activities in CP-induced rats were determined. Interestingly, these parameters were boosted, but with a decrement in radical species level in the testes/epididymis of CP-induced rats fed with RCNSD as against the untreated CP-induced rats. The modulatory effect of RCNSD on the tested reproductive parameters in studied tissues could be among the mechanism of action, by which RCNSD mitigates andrological toxicity. Hence, RCNSD could be harnessed as a functional food/nutraceutical agent for alleviating the andrological toxicity of CP-induced male reproduction. PRACTICAL APPLICATIONS: Consumption of cashew nuts has been a great benefit to human health, as a result of its richness in nutritional constituents including biologically active amino acids, tocopherols, fatty acids, polyphenols, and selenium, among others. Cashew nuts are mostly consumed fried/roasted, with yoghurt, as a paste, or used as an ingredient in confectionery products. The folkloric use of cashew nuts in the management of cardiovascular diseases, male reproductive disorders, and diabetes has been reported. In this study, the ability of roasted cashew nut-supplemented diets to modulate reproductive hormones, sperm parameters, testicular and epididymal antioxidant status, and steroidogenic enzymes activities in CP-induced reproductive toxicity in male rats was revealed, thus, indicating its possible use, clinically, in the management of reproductive toxicity induced by cancer drugs.

Natural anthraquinone compound emodin as a novel inhibitor of aurora A kinase: A pilot study.

Aurora kinase A (AURKA) carries out an essential role in proliferation and involves in cisplatin resistance in various cancer cells. Overexpression of AURKA is associated with the poor prognosis of cancer patients. Thus, AURKA has been considered as a target for cancer therapy. Developing AURKA inhibitors became an important issue in cancer therapy. A natural compound emodin mainly extracted from rhubarbs possesses anti-cancer properties. However, the effect of emodin on AURKA has never been investigated. In the present study, molecular docking analysis indicated that emodin interacts with AURKA protein active site. We also found nine emodin analogues from Key Organic database by using ChemBioFinder software. Among that, one analogue 8L-902 showed a similar anti-cancer effect as emodin. The bindings of emodin and 8L-902 on AURKA protein were confirmed by cellular thermal shift assay. Furthermore, emodin inhibited the AURKA kinase activity in vitro and enhanced the cisplatin-DNA adduct level in a resistant ovarian cancer cell line. It seems that emodin may have the potential to inhibit cancer cell growth and enhance cisplatin therapy in cancer with resistance. Collectively, our finding reveals a novel AURKA inhibitor, emodin, which may be vulnerable to ovarian cancer therapy in the future.

Evaluation of exposure risk for healthcare personnel performing the open technique HIPEC procedure using cisplatin.

OBJECTIVE: To perform an evaluation of the risk to healthcare personnel of exposure to cisplatin during a Hyperthermic Intraperitoneal Chemotherapy (HIPEC) procedure in an operating room environment. METHODS: Breathing zone air samples were taken from the operating room (OR) before, during and after the procedure of HIPEC filter membrane adsorption and the liquid impact method was applied to collect air samples. The samples of surface wipe from the floor of the OR were taken after the procedure. Inductively coupled plasma mass spectrometry(ICP-MS) was used to detect the content of cisplatin in all the samples. RESULTS: Thirty-six air samples and three surface wipes were collected from three different locations of healthcare personnel breathing zones. All the breathing zone air samples were negative for cisplatin; however, cisplatin contamination was detected on three surface wipes from the floor, but in a lowconcentration(≤ 2.25 ng). CONCLUSION: The results suggest that the risk of inhalation of cisplatin was extremely low for the healthcare personnel during the procedure of HIPEC, but the contamination of the OR floor should be taken into consideration.

Localized Delivery of Cisplatin to Cervical Cancer Improves Its Therapeutic Efficacy and Minimizes Its Side Effect Profile.

PURPOSE: Cervical cancer represents the fourth most frequent malignancy in the world among women, and mortality has remained stable for the past 4 decades. Intravenous cisplatin with concurrent radiation therapy is the standard-of-care for patients with local and regional cervical cancer. However, cisplatin induces serious dose-limiting systemic toxicities and recurrence frequently occurs. In this study, we aimed to develop an intracervical drug delivery system that allows cisplatin release directly into the tumor and minimize systemic side effects. METHODS AND MATERIALS: Twenty patient biopsies and 5 cell lines treated with cisplatin were analyzed for platinum content using inductively coupled plasma mass spectrometry. Polymeric implants loaded with cisplatin were developed and evaluated for degradation and drug release. The effect of local or systemic cisplatin delivery on drug biodistribution as well as tumor burden were evaluated in vivo, in combination with radiation therapy. RESULTS: Platinum levels in patient biopsies were 6-fold lower than the levels needed for efficacy and radiosensitization in vitro. Cisplatin local delivery implant remarkably improved drug specificity to the tumor and significantly decreased accumulation in the blood, kidney, and other distant normal organs, compared with traditional systemic delivery. The localized treatment further resulted in complete inhibition of tumor growth. CONCLUSIONS: The current standard-of-care systemic administration of cisplatin provides a subtherapeutic dose. We developed a polymeric drug delivery system that delivered high doses of cisplatin directly into the cervical tumor, while lowering drug accumulation and consequent side effects in normal tissues. Moving forward, these data will be used as the basis of a future first-in-human clinical trial to test the efficacy of localized cisplatin as adjuvant or neoadjuvant chemotherapy in local and regional cervical cancer.

Development of a Pre-assembled Through-Bond Energy Transfer (TBET) Fluorescent Probe for Ratiometric Sensing of Anticancer Platinum(ll) Complexes.

Fluorescence microscopy has emerged as an attractive technique to probe the intracellular processing of Pt-based anticancer compounds. Herein, we reported the first through-bond energy transfer (TBET) fluorescent probe NPR1 designed for sensitive detection and quantitation of PtII complexes. The novel TBET probe was successfully applied for ratiometric fluorescence imaging of anticancer PtII complexes such as cisplatin and JM118 in cells. Capitalizing on the ability of the probe to discriminate between PtII complexes and their PtIV derivatives, the probe was further applied to study the activation of PtIV prodrug complexes that are known to release active PtII species after intracellular reduction.

The latest advances of cisplatin liposomal formulations: essentials for preparation and analysis.

Introduction: Cisplatin has been indicated for several malignancies all over the world for many years. Increasing patient tolerance for high dose of chemotherapeutics and reducing side effects has been granted by drug encapsulated liposomal systems. There have been much efforts for improving cisplatin delivery to the site of action via liposomes both in research and clinical trials such as SPI-077®, Liplacis®, and Lipoplatin®.Areas covered: In this review, we have discussed about cisplatin and its liposomal formulations, focusing on different preparation methods and analysis approaches such as atomic absorption, mass spectroscopy, UV, electrochemical methods, and emphasizing on HPLC as one of the accurate and specific methods for determination of cisplatin species and also measurement of total platinum by derivation.Expert opinion: Liposome of cisplatin has offered potential beneficial aspects over cisplatin formulation. However, there are several challenges in preparing and analysis of cisplatin liposomes due to cisplatin's great reactivity, formation of several species, high affinity to bioelements, insufficient release at the tumor site, and inefficient loading. Cisplatin resistance is another challenge which should be prevented by higher loading capacity. Charge-dependent interactions should also be highly considered especially in the preparation step.

Detection of doxorubicin, cisplatin and therapeutic antibodies in formalin-fixed paraffin-embedded human cancer cells.

A major limitation in the pharmacological treatment of clinically detectable primary cancers and their metastases is their limited accessibility to anti-cancer drugs (cytostatics, inhibitory antibodies, small-molecule inhibitors) critically impairing therapeutic efficacies. Investigations on the tissue distribution of such drugs are rare and have only been based on fresh frozen material or methanol-fixed cell culture cells so far. In this paper, we expand the detection of cisplatin-induced DNA adducts and anthracyclines as well as therapeutic antibodies to routinely prepared formalin-fixed, paraffin-embedded sections (FFPE). Using pre-treated cell lines prepared as FFPE samples comparable to tissues from routine analysis, we demonstrate that our method allows for the detection of chemotherapeutics (anthracyclines by autofluorescence, cisplatin by immune detection of DNA adducts) as well as therapeutic antibodies. This methodology thus allows for analyzing archival FFPE tissues, as demonstrated here for the detection of cisplatin, doxorubicin and trastuzumab in FFPE sections of tumor xenografts from drug-treated mice. Analyzing human tumor samples, this will lead to new insights into the tissue penetration of drugs.

A BODIPY-based fluorescent sensor for the detection of Pt2+ and Pt drugs.

A BODIPY-based fluorescent sensor PS with an NO4S2 podand ligand was studied for the selective detection of Pt2+ over 21 cations as well as selected platinum drugs in aqueous medium. The platinum sensor PS shows 28-fold, 22-fold and 14-fold fluorescence turn-on enhancements to Pt2+, cisplatin and nedaplatin, and was thereby employed to detect platinum drugs in A-549 human lung cancer cells.

Occupational safety of pressurized intraperitoneal aerosol chemotherapy (PIPAC) in an operating room without laminar airflow.

AIM OF THE STUDY: The safety of pressurized intraperitoneal aerosol chemotherapy (PIPAC) is often questioned when newly implemented in an operating room (OR); as it may increase the risk of exposure to cytotoxics for healthcare workers. There are no data on the risk of healthcare exposure in OR without laminar airflow. We aimed to ensure the safety of PIPAC for surgeons and their co-workers for newly implemented procedures in an OR without laminar airflow. PATIENTS AND METHODS: Twenty-six samples with cellulosic wipes from surgeons and co-workers' environmental items and 5 specific polytetrafluoroethylene air-filtered collections were randomly performed for the first 2 cisplatin/doxorubicin-based PIPAC procedures in Strasbourg University Hospital. PIPAC was performed according to previously described safety protocol but without a laminar airflow and with an additional plastic cover and smoke evacuation device. Sampling and analyzes were performed by 2 accredited independent certified organizations. RESULTS: All air measurements were negative for cisplatin and doxorubicin. Only one wipe sample out of 26 was positive for cisplatin (4%) on the outer surgeon's pair of gloves but dosages on the surgeon's inner pair and hands were negative. CONCLUSION: When performed in approved security conditions, even without laminar airflow, PIPAC might seem harmless for surgeons and their co-workers with very limited risk of exposure to cytotoxics.

Saikosaponin b2 enhances the hepatotargeting effect of anticancer drugs through inhibition of multidrug resistance-associated drug transporters.

AIMS: Vinegar-baked Radix Bupleuri (VBRB) potentiates the activity of anticancer drugs in the liver by increasing their hepatic distribution. However, this phenomenon may be associated with drug transporters. We investigated the effect of saikosaponin b2 (SSb2; the main component of VBRB) on the activity and expression of different drug transporters in both normal cells and those that overexpress the transporter. MAIN METHODS: The activities of transporters were analyzed by concentration of their cellular substrates. Concentrations of colchicine (substrate of Pgp and MRP1) and cisplatin (substrate of OCT2 and MRP2) were determined by high-performance liquid chromatography (HPLC). The concentration of rhodamine B was determined by flow cytometry. The expression of transporter gene and protein were determined by qRT-PCR and Western blotting analysis. KEY FINDINGS: SSb2 increased colchicine efflux in HEK293 cells by primarily increasing Mrp1 activity, independent of gene and protein expression. SSb2 enhanced Mrp2 function and increased cisplatin efflux in BRL3A cells by upregulating Mrp2 gene expression, with a marginal effect on Pgp in normal cells. SSb2 increased OCT2 activity in OCT2-HEK293 cells by increasing the expression of OCT2 protein and mRNA; however, SSb2 inhibited MRP2 activity in MRP2-HEK293 cells by decreasing MRP2 protein expression, and decreased Pgp and MRP1 activity in Pgp- and MRP1-HEK293 cells. SIGNIFICANCE: SSb2 might potentially be the key active component of VBRB that enhances the hepatotargeting of anticancer drugs through the inhibition of multidrug resistance-associated drug transporters (Pgp, MRP1, and MRP2) in an environment-dependent manner.

Long-term, genome-wide kinetic analysis of the effect of the circadian clock and transcription on the repair of cisplatin-DNA adducts in the mouse liver.

Cisplatin is the most commonly used chemotherapeutic drug for managing solid tumors. However, toxicity and the innate or acquired resistance of cancer cells to the drug limit its usefulness. Cisplatin kills cells by forming cisplatin-DNA adducts, most commonly the Pt-d(GpG) diadduct. We recently showed that, in mice, repair of this adduct 2 h following injection is controlled by two circadian programs. 1) The circadian clock controls transcription of 2000 genes in liver and, via transcription-directed repair, controls repair of the transcribed strand (TS) of these genes in a rhythmic fashion unique to each gene's phase of transcription. 2) The excision repair activity itself is controlled by the circadian clock with a single phase at which the repair of the nontranscribed strand (NTS) and the rest of the genome takes place. Here, we followed the repair kinetic for long periods genome-wide both globally and at single nucleotide resolution by the Excision Repair-sequencing (XR-seq) method to better understand cisplatin DNA damage and repair. We find that transcription-driven repair is nearly complete after 2 days, whereas weeks are required for repair of the NTS and the rest of the genome. TS repair oscillates in rhythmically expressed genes up to 2 days post injection, and in all expressed genes, we see a trend in TS repair with time from the 5' to 3' end. These findings help to understand the circadian- and transcription-dependent and -independent control of repair in response to cisplatin, and should aid in designing cisplatin chemotherapy regimens with improved therapeutic indexes.

Gel electrophoresis in combination with laser ablation-inductively coupled plasma mass spectrometry to quantify the interaction of cisplatin with human serum albumin.

Cisplatin and its second and third generation analogues are widely used in the treatment of cancer. To study their reactions with proteins, we present a method based on SDS-PAGE separation and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) for platinum detection in the reaction between human serum albumin (HSA) and cisplatin. We developed matrix-matched standards of HSA/cisplatin mixtures and used them to quantify the amount of adducts formed at different HSA:cisplatin ratios. We noted that cisplatin incubation with HSA resulted in the formation of higher order HSA n-mers, depending on the amount of cisplatin added. This caused a depletion of the HSA dimer bands, while the majority of HSA was present as the monomer. Inducing the formation of such higher molecular weight species may have an impact on the mode of action of metallodrugs.

Tumor Platinum Concentrations and Pathological Responses Following Cisplatin-Containing Chemotherapy in Gastric Cancer Patients.

PURPOSE: There is a wide range in tumor response following preoperative chemotherapy in locally advanced gastric or gastroesophageal junction cancers. We investigated the relationship between tumor platinum levels and pathological responses in these patients. METHODS: Tumor and adjacent normal tissues were retrieved. Pathological responses were assessed per standard criteria. Tissue platinum concentrations were determined with high-performance liquid chromatography mass spectrometry. Platinum distribution in tissue components was evaluated with imaging mass cytometry. Collagen content was evaluated using trichrome staining. RESULTS: Surgical specimens from 10 patients were available. Surgery was performed at a median time of 49 days (range: 28-72) after the last cycle of chemotherapy. The mean platinum level in tumor tissue in patients with any response was significantly higher than in those with no response (893 ± 460 vs. 38.8 ± 8.8 pg, P = 0.007), so was the collagen content (37.4 ± 6.8 vs. 11.5 ± 8.6%, P < 0.05). Platinum preferentially bound to collagen. CONCLUSIONS: Platinum was detectable in surgical specimens up to 72 days after preoperative chemotherapy. Higher tumor platinum concentration correlated with improved pathological response. Collagen binding potentially explained the high interpatient variability in tumor platinum concentrations.

Transport of platinum-based pharmaceuticals in water-saturated sand and natural soil: Carboplatin and cisplatin species.

This study reports the transport characteristics of the pharmaceutical compounds carboplatin and cisplatin, and their respective derivatives, in saturated sand and soil columns. Pharmaceuticals are recognized as emerging pollutants of soil and water resources, but studies of the transport characteristics of organometallic pharmaceuticals in soil-water environments are rare. A recent study of oxaliplatin transport in natural soil raises the question of whether or not its behavior is representative of all Pt-based pharmaceuticals behavior in soil-water systems. To address this question, transport behaviors of carboplatin and cisplatin species were studied individually in packed sand columns under unamended conditions, and in packed soil columns under unamended and acetate-amended conditions. In contrast to oxaliplatin, carboplatin species exhibited very low affinity to both sand and soil surfaces: the retention of injected carboplatin was 3% and <6% for sand and soil, respectively. The affinity to soil was practically the same under the different redox conditions. The affinity of carboplatin to sand and soil surfaces was much smaller than the reported oxaliplatin affinity and the values reported in the literature. Cisplatin exhibited transport behavior similar to that of oxaliplatin in soil, including mild sensitivity to redox conditions (e.g., higher retention under acetate-amended conditions), overall exhibiting retention of 64-70% of the injected species. However, cisplatin also exhibited a similar retention in sand (retention of 45-53%), unlike the cases of carboplatin and oxaliplatin. The results indicate that similarly structured pharmaceuticals can exhibit very different transport characteristic in natural soil-water environments, and should therefore be studied and assessed individually.

Multisensor Imaging-From Sample Preparation to Integrated Multimodal Interpretation of LA-ICPMS and MALDI MS Imaging Data.

Laterally resolved chemical analysis (chemical imaging) has increasingly attracted attention in the Life Sciences during the past years. While some developments have provided improvements in lateral resolution and speed of analysis, there is a trend toward the combination of two or more analysis techniques, so-called multisensor imaging, for providing deeper information into the biochemical processes within one sample. In this work, a human malignant pleural mesothelioma sample from a patient treated with cisplatin as a cytostatic agent has been analyzed using laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) and matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS). While LA-ICPMS was able to provide quantitative information on the platinum distribution along with the distribution of other elemental analytes in the tissue sample, MALDI MS could reveal full information on lipid distributions, as both modes of polarity, negative and positive, were used for measurements. Tandem MS experiments verified the occurrence of distinct lipid classes. All imaging analyses were performed using a lateral resolution of 40 µm, providing information with excellent depth of details. By analyzing the very same tissue section, it was possible to perfectly correlate the obtained analyte distribution information in an evaluation approach comprising LA-ICPMS and MALDI MS data. Correlations between platinum, phosphorus, and lipid distributions were found by the use of advanced statistics. The present proof-of-principle study demonstrates the benefit of data combination for outcomes beyond one method imaging modality and highlights the value of advanced chemical imaging in the Life Sciences.

Optimized two-dimensional gel electrophoresis in an alkaline pH range improves the identification of intracellular CFDA-cisplatin-protein adducts in ovarian cancer cells.

Intracellular binding of cisplatin to proteins has been associated with acquired resistance to chemotherapy. In our previous study we established an analytical method for the identification of intracellular cisplatin-binding proteins. The method used a fluorescent carboxyfluorescein-diacetate-labeled cisplatin analogue (CFDA-cisplatin), two-dimensional gel electrophoresis (2DE) and mass spectrometry, which allows detecting and identifying intracellular CFDA-cisplatin-containing protein adducts in the acidic pH range (pH 4-7). Based on this analytical method we extended the identification of intracellular cisplatin-protein adducts to the alkaline pH range (pH 6-10) giving chance to discover new important binding partners. 2DE analysis of alkaline proteins is challenging due to the difficult separation of basic proteins during the isoelectric focusing (IEF). The establishment of an optimized IEF protocol for basic proteins enabled us to identify several intracellular CFDA-cisplatin-binding proteins including enzymes of the glucose and serine metabolism like alpha enolase and D-3-phosphoglycerate 1-dehydrogenase.

Cisplatin is retained in the cochlea indefinitely following chemotherapy.

Cisplatin chemotherapy causes permanent hearing loss in 40-80% of treated patients. It is unclear whether the cochlea has unique sensitivity to cisplatin or is exposed to higher levels of the drug. Here we use inductively coupled plasma mass spectrometry (ICP-MS) to examine cisplatin pharmacokinetics in the cochleae of mice and humans. In most organs cisplatin is detected within one hour after injection, and is eliminated over the following days to weeks. In contrast, the cochlea retains cisplatin for months to years after treatment in both mice and humans. Using laser ablation coupled to ICP-MS, we map cisplatin distribution within the human cochlea. Cisplatin accumulation is consistently high in the stria vascularis, the region of the cochlea that maintains the ionic composition of endolymph. Our results demonstrate long-term retention of cisplatin in the human cochlea, and they point to the stria vascularis as an important therapeutic target for preventing cisplatin ototoxicity.

Orthogonal Screening of Anticancer Drugs Using an Open-Access Microfluidic Tissue Array System.

Screening for potential drug combinations presents significant challenges to the current microfluidic cell culture systems, due to the requirement of flexibility in liquid handling. To overcome this limitation, we present here an open-access microfluidic tissue array system specifically designed for drug combination screening. The microfluidic chip features a key structure in which a nanoporous membrane is sandwiched by a cell culture chamber array layer and a corresponding media reservoir array layer. The microfluidic approach takes advantage of the characteristics of the nanoporous membrane: on one side, this membrane permits the flow of air but not liquid, thus acting as a flow-stop valve to enable automatic cell distribution; on the other side, it allows diffusion-based media exchange and thus mimics the endothelial layer. In synergy with a liquid-transferring platform, the open-access microfluidic system enables complex multistep operations involving long-term cell culture, medium exchange, multistep drug treatment, and cell-viability testing. By using the microfluidic protocol, a 10 × 10 tissue array was constructed in 90 s, followed by schedule-dependent drug testing. Morphological and immunohistochemical assays indicated that the resultant tumor tissue was faithful to that in vivo. Drug-testing assays showed that the incorporation of the nanoporous membrane further decreased killing efficacy of the anticancer agents, indicating its function as an endothelial layer. Robustness of the microfluidic system was demonstrated by implementing a three-factor, three-level orthogonal screening of anticancer drug combinations, with which 67% of the testing (9 vs. 27) was saved. Experimental results demonstrated that the microfluidic tissue system presented herein is flexible and easy-to-use, thus providing an ideal tool for performing complex multistep cell assays with high efficiencies.