Schedule-dependent reversion of acquired cisplatin resistance by 5-fluorouracil in a newly established cisplatin-resistant HST-1 human squamous carcinoma cell line

Concurrent 5-fluorouracil and carboplatin for the treatment of canine carcinomas

5-Fluorouracil (5-FU) is used in combination chemotherapy protocols for human head and neck cancer and other epithelial neoplasms. However, a paucity of literature describing use of this drug in veterinary oncology exists, likely due to previous reports of fatal neurotoxicity in both dogs and cats, mainly due to ingestion of human creams. The primary aim of this retrospective study was to report the safety of concurrent 5-FU and carboplatin in canine carcinomas. Secondarily, we aimed to look at the efficacy of the combination using overall response rate in treated dogs. Medical records were searched from 2007 to 2017 for dogs treated with both agents; 24 dogs met inclusion criteria. Carboplatin dosages ranged from 180 to 250 mg/m² (median 200 mg/m² ); 5-FU dosage was 150 mg/m² . Fourteen dogs had myelosuppression, ranging from Grade I to asymptomatic Grade IV; thrombocytopenia was more common than neutropenia. Gastrointestinal upset was uncommon, with only seven dogs having Grade I or II nausea, vomiting or diarrhoea. No cases were hospitalized for any of the above toxicities. One dog had an episode of ataxia, which could not be differentiated between otitis and 5-FU neurotoxicity. This protocol is well tolerated. Response rate in the gross disease setting was 43% (three complete responses, three partial responses). Prospective analysis of this combination protocol, and potentially 5-FU with other platinum agents, is warranted in the treatment of canine carcinomas.

Laser-assisted delivery of synergistic combination chemotherapy in in vivo skin

The effectiveness of topical drugs for treatment of non-melanoma skin cancer is greatly reduced by insufficient penetration to deep skin layers. Ablative fractional lasers (AFLs) are known to enhance topical drug uptake by generating narrow microchannels through the skin, but information on AFL-drug delivery in in vivo conditions is limited. In this study, we examined pharmacokinetics, biodistribution and toxicity of two synergistic chemotherapy agents, cisplatin and 5-fluorouracil (5-FU), following AFL-assisted delivery alone or in combination in in vivo porcine skin. Detected at 0-120 h using mass spectrometry techniques, we demonstrated that fractional CO₂ laser pretreatment (196 microchannels/cm², 852 μm ablation depth) leads to rapid drug uptake in 1500 μm deep skin layers, with a sixfold enhancement in peak cisplatin concentrations versus non-laser-treated controls (5 h, P = 0.005). Similarly, maximum 5-FU deposition was measured within an hour of AFL-delivery, and exceeded peak deposition in non-laser-exposed skin that had undergone topical drug exposure for 5 days. Overall, this accelerated and deeper cutaneous drug uptake resulted in significantly increased inflammatory and histopathological effects. Based on clinical scores and transepidermal water loss measurement, AFL intensified local toxic responses to drugs delivered alone and in combination, while systemic drug exposure remained undetectable. Quantitative histopathologic analyses correspondingly revealed significantly reduced epidermal proliferation and greater cellular apoptosis after AFL-drug delivery; particularly after combined cisplatin + 5-FU exposure. In sum, by overcoming the primary limitation of topical drug penetration and providing accelerated, enhanced and deeper delivery, AFL-assisted combination chemotherapy may represent a promising treatment strategy for non-melanoma skin cancer.

Downregulation of miR-363 increases drug resistance in cisplatin-treated HepG2 by dysregulating Mcl-1

Systemic therapy with cytotoxic agents provides marginal benefit in hepatocellular carcinoma (HCC) treatment especially for patients with advanced HCC. Cisplatin is one of the most active cytotoxic agents for HCC treatment. However, acquisition of cisplatin resistance is common, and one important underlying mechanism of such resistance is apoptosis-resistance. In this study, we found that miR-363 levels were significantly decreased in HCC patients treated with cisplatin-based chemotherapy. MiR-363 levels were also lower in cisplatin-resistant HepG2 (HepG2-R) cells than in HepG2 cells. Exogenous miR-363 significantly overcame cisplatin resistance in HepG2-R cells, whereas miR-363 knockdown increased the cell viability during cisplatin treatment. We further demonstrated that miR-363 directly targeted to Mcl-1 3'-UTR (3'-Untranslated Regions). Downregulation of miR-363 resulted in upregulation of Mcl-1 which is a key member of anti-apoptotic Bcl-2 family and increased drug resistance. We finally demonstrated that miR-363 decreased cisplatin resistance of HCC cell, partly by targeting Mcl-1. These data suggest that the combination of miR-363 and cisplatin may represent a novel approach in treatment for HCC, thus offering a new target for chemotherapy of HCC.

Downregulation of HIPK2 increases resistance of bladder cancer cell to cisplatin by regulating Wip1

Cisplatin-based combination chemotherapy regimen is a reasonable alternative to cystectomy in advanced/metastatic bladder cancer, but acquisition of cisplatin resistance is common in patients with bladder cancer. Previous studies showed that loss of homeodomain-interacting protein kinase-2 (HIPK2) contributes to cell proliferation and tumorigenesis. However, the role of HIPK2 in regulating chemoresistance of cancer cell is not fully understood. In the present study, we found that HIPK2 mRNA and protein levels are significantly decreased in cisplatin-resistant bladder cancer cell in vivo and in vitro. Downregulation of HIPK2 increases the cell viability in a dose- and time-dependent manner during cisplatin treatment, whereas overexpression of HIPK2 reduces the cell viability. HIPK2 overexpression partially overcomes cisplatin resistance in RT4-CisR cell. Furthermore, we showed that Wip1 (wild-type p53-induced phosphatase 1) expression is upregulated in RT4-CisR cell compared with RT4 cell, and HIPK2 negatively regulates Wip1 expression in bladder cancer cell. HIPK2 and Wip1 expression is also negatively correlated after cisplatin-based combination chemotherapy in vivo. Finally, we demonstrated that overexpression of HIPK2 sensitizes chemoresistant bladder cancer cell to cisplatin by regulating Wip1 expression.

Conclusions

These data suggest that HIPK2/Wip1 signaling represents a novel pathway regulating chemoresistance, thus offering a new target for chemotherapy of bladder cancer.

Long non-coding RNA UCA1 increases chemoresistance of bladder cancer cells by regulating Wnt signaling

Chemotherapy is a reasonable alternative to cystectomy in patients with invasive and advanced bladder cancer. However, bladder cancer cells often develop drug resistance to these therapies, and ~ 50% of patients with advanced bladder cancer do not respond to chemotherapy. Recent studies have shown that long non-coding RNA (lncRNA) is involved in the development of chemoresistance. Here we investigated the role of the urothelial cancer-associated 1 (UCA1) lncRNA in cisplatin resistance during chemotherapy for bladder cancer. We showed that cisplatin-based chemotherapy results in up-regulation of UCA1 expression in patients with bladder cancer. Similarly, UCA1 levels are increased in cisplatin-resistant bladder cancer cells. Over-expression of UCA1 significantly increases the cell viability during cisplatin treatment, whereas UCA1 knockdown reduces the cell viability during cisplatin treatment. UCA1 inhibition also partially overcomes drug resistance in cisplatin-resistant T24 cells. Furthermore, we showed that UCA1 positively regulates expression of wingless-type MMTV integration site family member 6 (Wnt6) in human bladder cancer cell lines. UCA1 and Wnt6 expression is also positively correlated in vivo. Up-regulation of UCA1 activates Wnt signaling in a Wnt6-dependent manner. We finally demonstrate that UCA1 increases the cisplatin resistance of bladder cancer cells by enhancing the expression of Wnt6, and thus represents a potential target to overcome chemoresistance in bladder cancer.

Upregulated miR-182 increases drug resistance in cisplatin-treated HCC cell by regulating TP53INP1

Chemotherapy plays a crucial role in hepatocellular carcinoma (HCC) treatment especially for patients with advanced HCC. Cisplatin is one of the commonly used chemotherapeutic drugs for the treatment of HCC. However, acquisition of cisplatin resistance is common in patients with HCC, and the underlying mechanism of such resistance is not fully understood. In the study, we focused on identifying the role of miRNAs in chemotherapy resistance after cisplatin-based combination chemotherapy. We assayed the expression level of miR-182 after cisplatin-based chemotherapy in patients with advanced HCC, and defined the biological functions by real-time PCR analysis and CCK-8 assay. We found that miR-182 levels were significantly increased in HCC patients treated with cisplatin-based chemotherapy. miR-182 levels were also higher in cisplatin-resistant HepG2 (HepG2-R) cells than in HepG2 cells. Upregulated miR-182 significantly increased the cell viability, whereas miR-182 knockdown reduced the cell viability during cisplatin treatment. miR-182 inhibition also partially overcame cisplatin resistance in HepG2-R cell. Furthermore, we found that upregulated miR-182 inhibited the expression of tumor suppressor gene TP53INP1 (tumor protein 53-induced nuclear protein 1) in vitro. In vivo, miR-182 and TP53INP1 expression was negatively correlated. We finally demonstrated that miR-182 increased cisplatin resistance of HCC cell, partly by targeting TP53INP1. These data suggest that miR-182/TP53INP1 signaling represents a novel pathway regulating chemoresistance, thus offering a new target for chemotherapy of HCC.

Sorafenib sensitizes hepatocellular carcinoma cell to cisplatin via suppression of Wnt/β-catenin signaling

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. Systemic chemotherapy plays an important role in the treatment of patients with advanced liver cancer. However, chemoresistance to cisplatin is a major limitation of cisplatin-based chemotherapy in the clinic, and the underlying mechanism of such resistance is not fully understood. In this study, we found that nuclear accumulation of β-catenin was higher in cisplatin-resistant Huh7 cells than in Huh7 cells, indicating that Wnt signaling was activated in cisplatin-resistant cells. Wnt signaling inhibition increased cisplatin-induced growth inhibition in hepatoma cell. We further demonstrated that sorafenib could inhibit Wnt signaling in Huh7 cells and cisplatin-resistant Huh7 cells. Co-treatment with cisplatin and sorafenib was more effective in inhibiting cancer cell proliferation than cisplatin alone in vitro and in vivo, whereas Wnt3a (Wnt activator) treatment abrogated sorafenib-induced growth inhibition. These data demonstrated that sorafenib sensitizes human HCC cell to cisplatin via suppression of Wnt/β-catenin signaling, thus offering a new target for chemotherapy of HCC.

Upregulated miR-130a increases drug resistance by regulating RUNX3 and Wnt signaling in cisplatin-treated HCC cell

Cisplatin is one of the commonly used chemotherapeutic drugs for the treatment of patients with advanced liver cancer. However, acquisition of cisplatin resistance is common in patients with hepatocellular carcinoma (HCC), and the underlying mechanism of such resistance is not fully understood. In the study, we found that miR-130a levels were significantly increased in HCC patients treated with cisplatin-based chemotherapy. miR-130a levels were also higher in cisplatin-resistant Huh7 cells than in Huh7 cells. Overexpression of miR-130a contributed to cisplatin resistance in Huh7 cell, whereas knockdown of miR-130a overcame cisplatin resistance in cisplatin-resistant Huh7 cell. We further demonstrated that upregulated miR-130a directly inhibited expression of tumor suppressor gene RUNX3, which resulted in activation of Wnt/β-catenin signaling and increased drug resistance. These data suggest that miR-130a/RUNX3/Wnt signaling represents a novel pathway regulating chemoresistance, thus offering a new target for chemotherapy of HCC.

Phase II Trial of Capecitabine and Cisplatin in Advanced, Persistent, or Recurrent Carcinoma of the Cervix

Purpose:

Platinum-based drugs are the most active agents in cervical carcinoma. The aim of this study was to assess the activity and toxicity of the association of cisplatin and capecitabine as first-line treatment in patients with advanced, persistent, or recurrent carcinoma of the cervix.

Patients and Methods:

Patients with histological proven primary carcinoma, presence of measurable tumors, age 18 years or older, performance status of 2 or less, and adequate bone marrow, renal, and hepatic functions were potentially eligible for this trial. Prior chemotherapy was allowed only in the context of radiosensitization. Treatment consisted of 50 mg/m2of intravenous cisplatin on day 1 with 2500 mg/m2oral capecitabine daily in 2 divided doses for 14 consecutive days in 21-day cycles. Responses were assessed using response evaluation criteria in solid tumors.

Results:

Between November 2004 and October 2007, 22 women were entered into the trial. Median age was 51 years (range, 37-70 years). Seventeen patients had prior radiotherapy, and 13 received a radiation sensitizer, whereas 2 patients underwent surgery exclusively and 3 patients had no prior treatment. A median of 5 cycles was administered (range, 2-8 cycles). There were one septic death, one grade 4 neutropenia, and one grade 4 anemia. Grade 3 fatigue, gastrointestinal toxicity, renal toxicity, and hand-foot syndrome were seen in 31.8%, 22.7%, 9%, and 9% of the patients, respectively. There were 1 complete response and 6 partial responses for an overall response rate of 31.8%. Seven patients (31.8%) each had stable disease, and 8 patients showed progression. The median time to progression was 7.6 months, with a median overall survival of 20 months.

Conclusion:

These results seem to suggest that the capecitabine-cisplatin combination is a moderately tolerated and active regimen in advanced, persistent, or recurrent cervical carcinoma patients. Further evaluation of this drug combination may be warranted.

Pretreatment with 5-FU enhances cisplatin cytotoxicity in head and neck squamous cell carcinoma cells

PURPOSE

In the treatment of head and neck malignancy, cisplatin and 5-FU have been used the most as chemotherapeutic agents. The difference in efficacies of these is unclear and controversial. To investigate more effective schedule, we analyzed the cytotoxicity in different treatment sequence with two agents in vitro and the mechanism for different effectiveness.

METHODS

UM-SCC-23 and UM-SCC-81B, head and neck squamous cell carcinoma cell lines, were analyzed for cellular killing in alternative sequence treatment with cisplatin and 5-FU. The treatment schedule was designed based on the clinical regimen. To determine the mechanism for the difference of cytotoxicity with each schedule, cell cycle distributions of both cells after 5-FU treatment with various durations were analyzed by flow-cytometry and immunostaining with anti-PCNA and anti-BrdU.

RESULTS

5-FU pretreatment followed by cisplatin treatment showed higher cell killing in both types of cells than the reverse treatment schedule. In the cell cycle analysis and immunostaining after the treatment of 5-FU, the rate of PCNA-positive cells was increased from 24 to 144 h in both cells. The rate of BrdU-positive cells of UM-SCC-81B in flow-cytometry was also increased, while that of UM-SCC-23 was gradually decreased. These data suggested that the cells treated with 5-FU for more than 144 h were still in the S-phase with or without DNA synthesis.

CONCLUSIONS

In head and neck carcinoma cells, we showed 5-FU pretreatment enhanced cisplatin cytotoxicity. The result of cell cycle analysis and immunostaining showed S-phase arrest by treatment of prolonged 5-FU treatment. The very long arrest in S-phase might be a mechanism to enhance cisplatin cytotoxicity by 5-FU pretreatment. We thus suggest pretreatment with 5-FU to enhance the effectiveness of cisplatin-based chemotherapy.

Infusional 5-fluorouracil and cisplatin as first-line chemotherapy in patients with carcinoma of unknown primary site

A combination chemotherapy of 5-fluorouracil (5-FU) and cisplatin (CDDP) has demonstrated activities in various malignancies, including head and neck, lung, esophageal, gastric, and pancreatic cancers. We reviewed our experience of 11 patients diagnosed as carcinoma of unknown primary site (CUPS), who were treated with infusional 5-FU and CDDP between January 1998 and December 2005. The median number of cycles administered was three (range: 1-12). All patients had measurable disease. Six partial responses were obtained (response rate: 54.5%, 95% confidence interval: 23.4-83.3%). The median survival time for all patients was 10 mo (range, 2-37 mo). The median time to disease progression was 3 mo (range, 1-6 mo). This regimen was well tolerated, with grade 3-4 neutropenia (two patients), febrile neutropenia (one patient), grade 3 nausea/vomiting (one patient), and grade 3 stomatitis (two patients). Grade 2 leukoencephalopathy was observed in one patient. No treatment-related death was observed. The combination chemotherapy of infusional 5-FU and CDDP was feasible and tolerated with promising activity for CUPS.

Evaluation of optimal drug concentration in histoculture drug response assay in association with clinical efficacy for head and neck cancer

Induction chemotherapy or concomitant chemoradiotherapy has been used increasingly to improve survival, organ preservation and function in patients with head and neck cancer (HNC). However, this regimen encounters significant side effects with potential adverse reactions causing many disadvantages for patients. Therefore, reliable chemosensitivity assays are needed to accurately predict the response to chemotherapy and guide the selection and treatment of patients with HNC. The main purpose of this study was to examine the optimal drug concentrations for evaluating in vitro chemosensitivity using the histoculture drug response assay (HDRA). The tested tumor specimens included 7 from oral cavities (14.3%), 12 from oropharynx (24.5%), 10 hypopharynx (20.4%), 3 larynx (6.1%), 5 sinonasal (10.2%), 2 salivary glands (4.1%), and 10 from metastatic lymph nodes (20.4%), respectively. Histopathologic types of all 49 specimens were squamous cell carcinoma. We investigated the optimal drug concentrations in HDRA searching at doses of 4-100 microg/ml for cisplatin and 60-1500 microg/ml for 5-FU. We considered the concentration of 20 microg/ml to be appropriate for evaluating cisplatin sensitivity in HNC among the tested dosages. As for cisplatin sensitivity in vitro, the 50% cut-off inhibition index (I.I.) was found to have a significant association with the clinical response to chemotherapy, with an accurate prediction rate of 77.8%. The HDRA shows a predictive value for chemosensitivity in HNC patients using the optimal drug concentration cut-off with this site specificity.

Metastatic basaloid-squamous cell carcinoma of the esophagus treated by 5-fluorouracil and cisplatin

Basaloid squamous cell carcinoma (BSC) of the esophagus is a rare malignant disease. We report here a patient with recurrent esophageal BSC, who was successfully treated by systemic chemotherapy containing 5-fluorouracil (5-FU) and cisplatin (CDDP). A 57-year-old woman was diagnosed as having squamous cell carcinoma of the esophagus upon endoscopic examination. Curative esophagectomy with lymph node dissection was performed under the thoracoscope. The pathological diagnosis of the surgical specimen was BSC. Five months after operation, the patient was diagnosed as having a recurrence of the BSC with metastases to the liver and spleen, and a right paraclavicular lymph node. She was given systemic chemotherapy consisting of continuous infusion of 800 mg/d of 5-FU and 3 h infusion of 20 mg/d of CDDP for 5 consecutive days every 4 wk. The metastatic lesions in the spleen and right paraclavicular lymph node disappeared, and the liver metastasis was apparently reduced in size after 2 courses of chemotherapy. The tumor regression was seen over 6 courses, with progression afterwards. Although subsequent treatment with CPT-11 and CDDP was not effective, docetaxel and vinorelbine temporarily controlled the tumor growth for 2 mo. 5-FU and CDDP combination may be useful for the patients with advanced BSC.

In-vitro schedule-dependent interaction between oxaliplatin and 5-fluorouracil in human gastric cancer cell lines

In order to define the most effective combination schedule of oxaliplatin (L-OHP) and 5-fluorouracil (5-FU), we investigated the in vitro interaction between these drugs in a panel of four human gastric adenocarcinoma cell lines (MKN-1, NUGC-3, NUGC-5 and AZ-521). Cytotoxic activity was determined by the WST-1 assay. Different schedules of the two drugs were compared and evaluated for synergism, additivity or antagonism with a quantitative method based on the median-effect principle of Chou and Talalay. Cell cycle perturbation and apoptosis were evaluated by flow cytometry. Simultaneous and sequential treatments of L-OHP followed by 5-FU exhibited synergistic effects in all four cell lines, whereas the reverse sequence yielded a clear antagonism. 5-FU exclusively arrested cells at the G0/G1 phase, and L-OHP at the G0/G1 and G2/M phases. Apoptosis was most prominent when cells were treated simultaneously or in a sequence of L-OHP followed by 5-FU, producing apoptosis in the majority of treated cells (55.5-61.5%). In contrast, the reverse sequence yielded only 20% induction of apoptosis, the rate being not significantly different from those induced by each drug singly. Moreover, this sequence dependence was further confirmed by the experiment which compared the total number of NUGC-3 cells 7 days after these combination schedules. These findings suggest that the interaction of 5-FU and L-OHP could be highly schedule dependent, with the most efficacious interaction observed in simultaneous combination and that 5-FU followed by L-OHP would not be recommended in clinical trials for patients with advanced gastric cancer.

Enhancement of the anti-tumor activity of S-1 by low-dose cisplatin in mice bearing the sarcoma-180 model

The combination of S-1, consisting of 1 mol/l tegafur, 0.4 mol/l 5-chloro-2,4-dihydroxypyridine and 1 mol/l potassium oxonate, plus low-dose cisplatin has showed promising anti-tumor activities in experimental and clinical studies. The aim of this study was to investigate the mechanism of this combination chemotherapy. Mice bearing sarcoma-180 cells were divided into groups of seven animals each - Group A: no treatment; Group B: 5-fluorouracil (5-FU) 10 mg/kg continuous i.p. infusion; Group C: S-1 10 mg/kg p.o.; Group D: cisplatin 0.2 mg/kg i.p.; Group E: B+D; Group F: C+D. Treatments were given for 5 consecutive days, and then anti-tumor activity, the concentration of 5-FU, the thymidylate synthase inhibition rate (TSIR) and the level of 5-FU incorporated into RNA (F-RNA) in tumor tissue were evaluated. Anti-tumor activity in Group F was higher than in any other group. A significantly higher concentration of 5-FU in tumor was detected in the S-1-treated groups (C and F) than in the 5-FU-treated groups (B and E). No differences in TSIR were observed between the groups treated with 5-FU or S-1 with or without cisplatin; however, the F-RNA level in Group F was about 1.24 times significantly higher than that in Group C. Group F showed the highest anti-tumor activity, with increasing intratumoral levels of 5-FU and F-RNA, but not that of TSIR. These results suggested that the superior anti-tumor activity obtained by S-1+cisplatin might be associated with an incorporation of 5-FU into RNA.

Feasibility study of ambulatory continuous infusion of 5-fluorouracil followed by cisplatin through hepatic artery for metastatic colorectal cancer

PURPOSE

A great synergy has been reported in a number of preclinical studies when 5-fluorouracil (5-FU) precedes cisplatin (CDDP). The objective of this study was to determine the feasibility of ambulatory continuous infusion of 5-FU followed by CDDP through hepatic artery for metastatic colorectal cancer.

PATIENTS AND METHODS

Seventeen patients with unresectable liver metastases, who underwent primary tumor resection, were treated with 5-FU (450 mg/m2/day) for seven consecutive days followed by CDDP (100 mg/body/week) for seven consecutive days, each administered continuously by using a balloon pump via Infuse-A-Port catheter inserted into common hepatic artery. The doses of drugs were reduced 20% in patients older than 70 years. The treatment was repeated every 4-6 weeks until disease progression.

RESULTS

Of 17 assessable patients, nine patients showed PR (53%; 95% CI, 29.3-76.7%) and eight patients had SD (47%; 95% CI, 23.3-70.7%), with disease control rate of 100%. The median overall survival was 26 months (95% CI: 17.5-41 months) and TTP 14 months (95% CI: 11-20.3 months). Two patients (11.8%), who showed progression due to collateral feeding arteries, responded to HAI again after occlusion. Grade 3 toxicity included leukopenia (12%) and anemia (24%). Grade 4 toxicity was absent. Four patients (23.5%) progressed at extrahepatic sites.

CONCLUSIONS

This sequential combination of 5-FU followed by CDDP through hepatic artery is active and safe in an outpatient setting, and warrants further multi-institutional study, although prevention of micrometastasis would be mandatory to further prolong overall survival.

Intensified bimonthly cisplatin with bolus 5-fluorouracil, continuous 5-fluorouracil and high-dose leucovorin (LV5FU2) in Patients with advanced gastrointestinal carcinomas: a phase I dose-finding and pharmacokinetic study

5-fluorouracil (5FU) and cisplatin are commonly used in the treatment of gastric cancer. Continuous 5FU appears to be more effective and less toxic than bolus administration, while increasing the dose intensity of cisplatin may be advantageous. We conducted a phase I study to establish the maximum tolerated dose (MTD) of cisplatin, which could be combined with a hybrid bolus/continuous 5-FU regimen (LV5FU2), given every 2 weeks. Thirty-six patients with advanced upper gastrointestinal carcinomas entered the study. Starting cisplatin dose was 40 mg/m2 and it was increased by 10 mg/m2 in cohorts of 3-6 patients. The pharmacokinetics of 5-fluorouracil in 14 patients were compared with those of 6 patients receiving LV5FU2 alone. All patients received prophylactic granulocyte colony-stimulating factor at cisplatin doses > or =50 mg/m2. MTD was reached at 100 mg/m2 of cisplatin and, therefore, the 90 mg/m2 dose is recommended for phase II studies. Bone marrow toxicity was the most frequent dose-limiting toxicity with 1 patient dying of neutropenic sepsis. Grade III/IV neutropenia was observed in 10 patients (27.7%). Nonhematological toxicity was infrequent and mild. Pharmacokinetic analysis showed that the addition of 90 mg/m2 or 100 mg/m2 of cisplatin to LV5FU2 significantly reduced the 5FU area under the curve. Objective response rate in 23 evaluable patients was 39.2%. The combination of LV5FU2 with bimonthly 90 mg/m2 cisplatin is feasible and active and should be further evaluated in patients with advanced gastric cancer.

Phase I study of combination chemotherapy with 5-fluorouracil (5-FU) and nedaplatin (NDP): adverse effects and eecommended dose of NDP administered after 5-FU

When nedaplatin (NDP) was used as a single agent in the phase I study, the dose-limiting toxicity (DLT) was thrombocytopenia and the recommended dose (RD) was 100 mg/m2. However, the DLT, maximum tolerated dose (MTD) and RD of NDP used in combination with 5-fluorouracil remained unknown. Therefore, we performed this study to assess the DLT and RD of NDP administered after 5-fluorouracil (5-FU). In this study, 5-FU was administered to 38 patients at a fixed dose (700 mg/m2/d on days 1-5) and NDP administered on day 6 at an initial dose of 80 mg/m2, which was subsequently increased to 100, 120, 130, 140, 150, and 160 mg/m2. The DLT of NDP was leukopenia and its MTD and RD were 160 and 150 mg/m2, respectively. Concerning impairment of renal function, only two patients had a grade I increase in serum creatinine. There were 19 responders (50%, 19/38) achieving partial response or complete response in the evaluation of antitumor effect. The result of this study is notable in that administration of 5-FU before NDP allows the dose of NDP to be substantially increased.

Growth inhibitory effect of a new camptothecin analog, DX-8951f, on various drug-resistant sublines including BCRP-mediated camptothecin derivative-resistant variants derived from the human lung cancer cell line PC-6

DX-8951f, a new water-soluble camptothecin (CPT) derivative, has been reported to show potent antitumor effects against various tumors in vitro and in vivo. We further evaluated the cytotoxic effect of DX-8951f against eight drug-resistant sublines derived by stepwise exposure of human oat cell carcinoma PC-6 to various drugs. In paclitaxel-, adriamycin-, vincristine- and etoposide-resistant cells, overexpression of P-glycoprotein (P-gp) and a correlative reduction in drug accumulation and typical drug-sensitivity pattern were confirmed. The etoposide-resistant line with the highest P-gp level was cross-resistant also to SN-38, CPT-11 and topotecan (TPT), but not to 9-aminocamptothecin (9-AC), CPT and DX-8951f. SN-38- and CPT-11-resistant cells, of which topoisomerase I activities and levels were similar to those of the parent cells, showed cross-resistance clearly to TPT, 9-AC and mitoxantrone, but hardly to DX-8951f. In these two resistant sublines, the intracellular topotecan level was significantly lower than that in parental PC-6 and the reduced accumulation was found to be mediated by breast cancer resistant protein (BCRP). The cisplatin-resistant variant, which had a 2-fold increase in glutathione content, showed no cross-resistance and the 5-fluorouracil-resistant variant, which had a 50% decrease in glutathione content, exhibited collateral sensitivity to most of the other anticancer agents including DX-8951f. We concluded that DX-8951f showed a potent cytotoxic effect on various types of drug-resistant cells.

MFL-P Chemotherapy for Pretreated Metastatic Breast Cancer Patients: A Regimen with Triple Biochemical Modulation by MTX-5FU, LV-5FU and 5FU-CDDP

BACKGROUND: Chemotherapeutic regimens, such as cyclophosphamide + doxorubicin + 5FU (CAF) or cyclophosphamide + methotrexate + 5FU (CMF), are sometimes used in combination with endocrine or radiotherapy as a standard first line of treatment for recurrent or metastatic breast cancer. However, many cases are, or become, refractory to these treatments. METHODS: Twenty-one women with recurrent or metastatic breast cancer who previously underwent treatment were administered our original regimen of combinationchemotherapy, MFL-P: Day 1, bolus methotrexate (MTX) 50 mg/body (median dose, 33 mg/m(2); range, 29-35 mg/m(2)) and 4 hours later 5-fluorouracil (5FU) 750 mg/body/h (median dose, 497 mg/m(2)/h; range, 441-528 mg/m(2) /h); Days 2-3, bolus leucovorin(LV) 15 mg/body every 8 h x 3; Days 2-5, 72 hours continuous 5FU 750 mg/body/24h; Day 6, cisplatin (CDDP) 50 mg/body/h (median dose, 33 mg/m(2)/h; range, 29-35 mg/m(2) /h) with sufficient hydration. The subjects ranged in age from 26 to 63 years (mean age, 51.3 years). RESULTS: One complete and 9 partial responses were achieved among the 20 patients (response rate, 50%). In 1 patient, diffuse liver metastasis was not measurable. Among various metastatic sites, a higher response rate was observed especially for soft tissue lesions (skin, chest wall and lymph nodes; 9 responders among 11 lesions). On the other hand, in visceral or skeletal metastases, the response rate was poor. The adverse effects were tolerable in all patients, except for common low-grade stomatitis or anorexia. CONCLUSION: MFL-P is useful as a second or third line of therapy for patients with refractory, recurrent or metastatic breast cancer with soft tissues lesions.

Raltitrexed (Tomudex) in combination with platinum-based agents and/or anthracyclines: preliminary results of phase I clinical trials

Three ongoing, dose-escalation, phase I studies are evaluating the combination of raltitrexed with oxaliplatin or anthracyclines (with and without cisplatin). In study 1, patients with advanced solid tumours received 2.0-3.75 mg/m2 raltitrexed, followed 45 min later by 85-130 mg/m2 oxaliplatin (2-h infusion) every 3 weeks. In study 2, patients with advanced oesophageal or gastric adenocarcinoma received 2.0-3.0 mg/m2 raltitrexed with 50 mg/m2 intravenous (i.v.) epirubicin and 60 mg/m2 i.v. cisplatin every 3 weeks. In study 3, patients with advanced or metastatic gastric cancer received 2.5-3.5 mg/m2 raltitrexed followed by 30-60 mg/m2 i.v. doxorubicin every 3 weeks. In all studies, raltitrexed was given as a 15-min infusion. All the combinations evaluated were administered in convenient 3-weekly schedules and were generally well tolerated. Recommended doses for raltitrexed and oxaliplatin are the same in combination as for single-agent use, i.e. 3.0 mg/m2 raltitrexed and 130 mg/m2 oxaliplatin. The recommended dose of raltitrexed in combination with cisplatin and epirubicin is 2.5 mg/m2. No dose-limiting toxicities were observed during co-administration of the full single-agent doses of raltitrexed and doxorubicin (3.0 mg/m2 and 60 mg/m2, respectively); dose escalation is continuing. Preliminary efficacy results were encouraging, particularly for the combination of raltitrexed and oxaliplatin in patients with mesothelioma and advanced colorectal cancer. Preliminary data from these phase I studies suggest that the combination of raltitrexed with platinum-based agents and/or anthracyclines may represent useful regimens for the treatment of patients with advanced cancer. Further studies are required to identify the most effective combinations of raltitrexed with both established and new anticancer agents.

Expression of DNA repair proteins hMSH2, hMSH6, hMLH1, O6-methylguanine-DNA methyltransferase and N-methylpurine-DNA glycosylase in melanoma cells with acquired drug resistance

Malignant melanoma is well known for its primary unresponsiveness to chemotherapy. The mechanisms conferring this intrinsic resistance are unclear. In this study, we investigated the role of genes involved in DNA repair in a panel of human melanoma cell variants exhibiting low and high levels of resistance to 4 commonly used drugs in melanoma treatment, i.e., vindesine, etoposide, fotemustine and cisplatin. We show that in melanoma cells exhibiting resistance to cisplatin, etoposide and vindesine, the nuclear content of each of the DNA mismatch repair (MMR) proteins hMLH1, hMSH2 and hMSH6 was reduced by 30-70%. A decreased expression level of up to 80% of mRNAs encoding hMLH1 and hMSH2 was observed in drug-resistant melanoma cells selected for cisplatin, etoposide and fotemustine, while vindesine-selected cells showed only moderate reduction. In melanoma cells that acquired resistance to fotemustine, the amount of nuclear MMR proteins was nearly unaltered, whereas the activity of O6-methylguanine-DNA methyltransferase (MGMT) was considerably enhanced. Activity of N-methylpurine-DNA glycosylase (MPG) was not significantly altered in any of the drug-resistant melanoma cells. Our data indicate that modulation of both MMR components and MGMT expression level may contribute to the drug-resistant phenotype of melanoma cells.

Regulation of CD95 (Apo-1/Fas) ligand and receptor expression in squamous-cell carcinoma by interferon-gamma and cisplatin

CD95 (Apo-1/Fas) ligand (CD95L) expression has been observed in various malignancies. In human primary cell lines from a squamous cell carcinoma (SCC) of the vulva, the effect of cisplatin (CDDP) and IFNgamma on the expression of CD95L and its 2 receptor isoforms, CD95 transmembrane (CD95tm) and CD95 soluble receptor, was studied at the mRNA and protein levels. Addition of CDDP and IFNgamma increased CD95L mRNA levels in the primary cell line 6-fold and 1.7-fold, respectively. In comparison, CD95tm mRNA levels were diminished by CDDP but increased 8-fold upon IFNgamma challenge. CD95L expressed by SCC cells was functionally relevant since these cells were able to induce CD95-specific apoptosis in autologous lymphocytes from the SCC-bearing patient. Thus, CD95L expression in SCC may contribute to tumor-associated immunosuppression, which may be modulated by CDDP and IFNgamma. In tumor samples of the primary SCC, CD95L expression was enhanced in the area of the border between invasive tumor tissue and surrounding stroma cells. The locally restricted over-expression of CD95L was congruent with the arrangement of apoptotic stroma cells in the direct vicinity of invading tumor tongues, suggesting a role as invasion factor for CD95L.

Sequence-dependent antitumour efficacy of combination chemotherapy of nedaplatin, a novel platinum complex, with 5-fluorouracil in an in vivo murine tumour model

The antitumour efficacy of a sequential combination of nedaplatin (NDP) and 5-fluorouracil (5-FU) was evaluated using Lewis lung carcinoma in vivo. NDP was developed as a second generation platinum complex. Because it has greater antitumour activity and lower nephrotoxicity than cisplatin (CDDP), we also compared the antitumour activity of NDP plus 5-FU with that of CDDP plus 5-FU. A fixed 5-FU dose was injected daily for 5 days and increasing doses of either NDP or CDDP were injected once via the tail vein into the Lewis lung carcinoma-implanted mice. The sequential administration of either NDP or CDDP prior to 5-FU (NF or CF therapy) resulted in severe body weight loss followed by the death of the tumour-bearing mice when the high-dose of NDP or CDDP was administered. In contrast, the sequential administration of 5-FU prior to NDP or CDDP (FN or FC therapy) resulted in synergistically enhanced inhibition of tumour growth and prolonged survival in comparison with NDP, CDDP or 5-FU monotherapy. At the high-dose of NDP in FN therapy, a reduction of tumour size and long-term tumour-free survival were frequently observed. The survival effect of the combinations of NDP with 5-FU was superior to those of the combination of CDDP with 5-FU. In conclusion, the sequence-dependent antitumour efficacy and toxicity of the combination of NDP or CDDP with 5-FU was demonstrated in this study, and FN therapy appeared to be the most efficient regimen as a clinical therapy.