Interactions of doxorubicin and cis-platin in squamous carcinoma cells in culture

Abstract

Summary Doxorubicin (DXR) has a positive inoculum effect and penetrates poorly into the core of multicellular tumour spheroids (MTS). Cis-platin (DDP) displays neither of these characteristics. We evaluated whether combining these 2 agents would influence the cell kill effect at a tumour mass level. MTS were produced from a PC-10 squamous lung carcinoma cell line. MTS were exposed to either drug first for h with different intervals between exposure. Cells were then trypsinized to a single cell suspension and subjected to clonogenic assay. Combination effects were analyzed by median effect plot analysis. The more MTS ml-' medium, the lower the cell kill effect of DXR. Simultaneous exposure to the 2 drugs was synergistic. DXR exposure first followed by DDP was less efficacious than, or the same as, the simultaneous exposure. In contrast, DDP followed by DXR was more efficacious with the best cell kill at a 1 h interval between each drug. This phenomenon was observed even at non-toxic doses of DDP. The fluorescent microscopic study of DXR indicated that prior exposure of MTS to DDP resulted in increased DXR penetration into the MTS core leading to heightened synergism with this sequence. These data suggest that the proper combination of DXR plus DDP should be in sequence with DDP first. Clinical, toxicological and pharmacological trials of DDP administration first, followed by DXR, are warranted.Doxorubicin (DXR) and cis-platin (DDP) are both highly active anticancer agents widely used in the treatment of human cancer. We introduced a combination of these 2 agents, termed A & P (adriamycin and platinum) (Vogl et al., 1976), which has become the basis, by adding more drugs, for the treatment of patients with ovarian cancer, small cell lung cancer and other neoplasms. Recently, we have demonstrated that DXR has a positive inoculum effect in vitro and loses efficacy at high cell densities, whereas DDP does not (Ohnuma et al., 1986). Moreover, we have shown that DXR penetrates poorly into the core of multicellular tumour spheroids (MTS) whereas DDP shows no such penetration gradient (Inoue et al., 1985). These pharmacological differences at the tumour mass level indicate that DXR should be best used when tumour size is small and cell density low. Therefore, we hypothesized that the proper sequence of A & P should be DDP first, followed by DXR, rather than vice versa. This communication sets forth the experimental proof of our hypothesis and elucidates a possible mechanism for this effect. Materials and methodsHuman tumour cell line PC-10 squamous lung carcinoma cell line was used in these experiments (Kinjo et al., 1979). Cells were maintained as a monolayer in RPMI-1640 medium (GIBCO, Grand Island, NY), supplemented with 10% (v/v) heat-inactivated foetal bovine serum (FBS) (Gibco) at 37"C in a 5% CO2/95% humidified air atmosphere. These cells were subcultured after trypsinization with 0.2% trypsin (Type III from Conditions of drug exposure and determination of cell survival After 3 weeks of culture, MTS with a diame...

Cancer cell spheroids as a model to evaluate chemotherapy protocols

“…29 A different incubation time with cisplatin may be required to observe an enhancement since this agent's sensitizing property was shown to be time-dependent both in vitro and in vivo. 29,31 We observed no LDh release (white bars) was measured (Fig. 1).…”

“…6,15,25,26 We evaluated combinations of clinically relevant drugs belonging to different groups: mitoxantrone (anthracenedione), cisplatin (alkylating-like), dexamethasone (glucocorticosteroid), methotrexate (antifolate), sclareol (labdane diterpene), paclitaxel (taxane) and doxorubicin (anthracycline). In vitro use of these drugs in combination protocols was reported for sclareol and methotrexate, 27,28 in vivo for paclitaxel, cisplatin and dexamethasone; 8,[29][30][31] and with patients for doxorubicin, paclitaxel, mitoxantrone and methotrexate. [16][17][18][32][33][34] Their sequential combination with doxorubicin in a spheroid model was studied in this report.…”

Docetaxel suppresses invasiveness of head and neck cancer cells in vitro

“…Because 3D multicellular tumor spheroids provide a microenvironment that mimics tumors in vivo, (10) spheroid culture has been used to evaluate tumor cell invasiveness and ⁄ or its responsiveness to anticancer drugs. (11)(12)(13)(14)(15) At IC 10 determined in monolayer culture, both cisplatin or docetaxel did not affect filopodia formation. However, at IC 50 also determined in monolayer culture, docetaxel, but not cisplatin, significantly decreased filopodia formation in HEp-2 cells in spheroid culture (Fig.…”

Hyperthermic intraperitoneal intraoperative chemotherapy after cytoreductive surgery for the treatment of abdominal sarcomatosis

“…The failure of postoperative intraperitoneal drug administration may be correlated with heterogeneous drug distribution caused by early postoperative adhesions entrapping tumor cells and protecting them from the chemotherapeutic agents 23. In addition, some antineoplastic drugs (e.g., doxorubicin and cisplatin) act synergistically with each other24, 25 and with heat,26, 27 which led some authors to propose hyperthermic intraperitoneal intraoperative chemotherapy (HIIC) for the treatment of locally advanced intraabdominal malignancies 17, 28. The results of cytoreductive surgery combined with HIIC for the treatment of gastrointestinal carcinomas have been encouraging 18, 29–38.…”

“…As a single drug regimen, it has been administered intraperitoneally in patients with advanced ovarian carcinoma, but patients develop high local toxicity 40. Some studies demonstrated in preclinical models that doxorubicin activity is enhanced by the addition of cisplatin24, 25 and/or hyperthermia 26, 27, 41. This potential synergy might be exploited to reduce the doxorubicin dosage (and thus minimize doxorubicin‐related local toxicity) while still maintaining the therapeutic activity of the cytotoxic regimen.…”