IGROVCDDP cisplatin-resistant cells have an unusual resistant phenotype; they are cross resistant to paclitaxel as they overexpress P-gp (90). to chemotherapy agents. Doses of drug are higher and escalated over time. It is common to have difficulty developing stable clinically relevant drug-resistant cell lines. A comparative selection strategy of multiple cell lines or multiple chemotherapeutic agents mitigates this risk and gives insight into which agents or type of cell line develops resistance easily. Successful selection strategies from our research are presented. Pulsed-selection produced platinum or taxane-resistant large cell lung cancer (H1299 and H460) and temozolomide-resistant melanoma (Malme-3M and HT144) cell lines. Continuous selection produced a lapatinib-resistant breast cancer cell line (HCC1954). Techniques for maintaining drug-resistant cell lines are outlined including; maintaining cells with chemotherapy, pulse treating with chemotherapy, or returning to master drug-resistant stocks. The heterogeneity of drug-resistant models produced from the same parent cell line with the same chemotherapy agent is explored with reference to P-glycoprotein. Heterogeneity in drug-resistant cell lines reflects the heterogeneity that can occur in clinical drug resistance. model, which exhibited acquired resistance to a chemotherapy drug, was published in 1970 (1). Resistant cell lines were developed from parental Chinese hamster cells using a stepwise increase in treatment dose with actinomycin D. This induced 2500-fold greater resistance to the drug than that observed in Capreomycin Sulfate the parental Capreomycin Sulfate cells. These resistant cell lines were also cross resistant to other chemotherapy drugs such as vinblastine and daunorubicin. Some earlier drug-resistant cell lines were developed in the 1950 and 1960s using mouse models, including models resistant to methotrexate (2, 3), vinblastine, terephthalanilide (4), and the guanine analog, 8-azaguanine (5). Publications in this research field usually place little emphasis on how the drug-resistant cell lines were established in the laboratory. The development of drug-resistant cell lines can take anything from 3 to 18?months in the laboratory and many decisions are taken along Capreomycin Sulfate this journey. This review summarizes the major methodological approaches for developing drug-resistant cell lines with reference to the literature and includes several case studies from our experience. IC50 values and fold resistance Drug-resistant cell models are developed in the laboratory by repeatedly exposing cancer cells growing in cell culture to drugs. The surviving daughter resistant cells are then compared to the parental sensitive cells using combination cell viability/proliferation assays such as the MTT (6), acid phosphatase (6), or clonogenic assays (7). The sensitivity of these paired cell lines is usually determined by exposing them to a range of drug concentrations and then assessing cell viability. The IC50 (drug concentration causing 50% growth inhibition) for these paired cell lines can be used to determine the increase in resistance known as fold resistance by the following equation: math xmlns:mml=”http://www.w3.org/1998/Math/MathML” display=”block” id=”M1″ overflow=”scroll” mtable columnalign=”left” class=”align-star” mtr mtd columnalign=”right” class=”align-odd” mi mathvariant=”normal” Fold?Resistance /mi /mtd mtd class=”align-even” mo class=”MathClass-rel” = /mo msub mrow mi mathvariant=”normal” IC /mi /mrow mrow mn 50 /mn /mrow /msub mtext ? Capreomycin Sulfate /mtext mi mathvariant=”normal” of /mi mtext ?Resistant?Cell?Line /mtext mo class=”MathClass-bin” M /mo msub mrow mi mathvariant=”normal” IC /mi /mrow mrow mn 50 Capreomycin Sulfate /mn /mrow /msub mi mathvariant=”normal” ?of?Parental /mi mspace width=”2em” /mspace /mtd mtd columnalign=”right” class=”align-label” /mtd mtd class=”align-label” mspace width=”2em” /mspace /mtd /mtr mtr mtd columnalign=”right” class=”align-odd” /mtd mtd class=”align-even” mspace width=”1em” class=”quad” /mspace mi mathvariant=”normal” ?Cell?Line /mi mspace width=”2em” /mspace /mtd mtd columnalign=”right” class=”align-label” /mtd mtd class=”align-label” mspace width=”2em” /mspace /mtd /mtr /mtable /math What is a Clinically Relevant Level of Resistance? To determine the level of drug resistance that occurs in the clinical treatment of cancer we can compare cell lines that have been established from cancer patients Rabbit polyclonal to KCTD17 before and after chemotherapy (Table ?(Table1)1) (8C14). The majority of cell lines listed in Table ?Table11 developed from patients post-chemotherapy show a two- to five-fold increase in resistance to the providers the individuals were treated with, based on a comparison of IC50 ideals. Three cell lines experienced higher levels of resistance but they were still relatively low-level at ~8C12-collapse higher than the parental cells (PEO4, SK-3, and GLC-16). Table 1 Cell lines founded from cancer individuals before and after chemotherapy. thead th align=”remaining” rowspan=”1″ colspan=”1″ Malignancy type /th th align=”remaining” rowspan=”1″ colspan=”1″ Parent cell collection (founded) /th th align=”remaining” rowspan=”1″ colspan=”1″ Chemotherapy received /th th align=”remaining” rowspan=”1″ colspan=”1″ Resistant cell collection (founded) /th th align=”remaining” rowspan=”1″ colspan=”1″ Collapse resistance to chemotherapy received /th th align=”remaining” rowspan=”1″ colspan=”1″ Research /th /thead LungEBC-2 (18th September 1997)CIS, IFO, VINDEBC-2/R (4th October 1997)CIS C 2.3, IFOa C 3.2, VIND C 0.77(8)SK-1 (August 1986)CYC, ADR, ETO, VINC, RADSK-2 (March 1987)ADR C 1.2, ETO C 1.2, CYCb C 1.3(10)CIS, ETOSK-3 (May 1987)CIS C 8.6, ETO C 6.2TM1 (April 1987)CYC, ADR, ETO, VINCTM2 (September 1987)CYCb C 5.4, ADR C 3.0, ETO C 3.5GLC-14 (December 1984)CYC, DOX, ETOGLC-16 (October 1985)DOX C 3.18, ETO C 12.1(11)NeuroblastomaKP-N-AY (October 1984)ADR, CIS,.