Potential of the Akt inhibitor LY294005 to antagonize the efficacy of Cisplatin against HCT116 tumor cells in a DNA mismatch repair-dependent manner.

Human colorectal adenocarcinoma sublines either deficient (HCT116+ch2) or proficient (HCT116+ch3) in the function of MLH1, one of five proteins crucial to DNA mismatch repair (MMR), were used to investigate whether the Akt-specific inhibitor LY294005 could not only increase the efficacy of platinum drugs in HCT116 cells in general but also increase the efficacy of the cisplatinum compounds Cisplatin and Lipoplatin specifically in MLH1-deficient, Cisplatin- and Lipoplatin-resistant HCT116 cells. We report that, under the conditions it increased the efficacy of Docetaxel and did not affect that of 6-thioguanine, LY294005 decreased the sensitivity of both sublines to Cisplatin, Lipoplatin, Oxaliplatin, and Lipoxal. Notably, the LY294005-imposed decrease was significantly higher in the MLH1-proficient than in the MLH1-deficient subline with Cisplatin and Lipoplatin, whereas it was nearly the same in both sublines with Oxaliplatin and Lipoxal. These LY294005-imposed changes in drug sensitivity, i.e. increase with Docetaxel and decreases with platinum compounds, were not associated with the concomitant abrogation in the levels of phospho-Aktser473. Analogous changes in drug sensitivity were also observed with the PI3-kinase inhibitor LY294002, but these changes were associated with complete abrogation of phospho-Aktser473. These observations suggest a possible relationship between MMR-mediated cisplatinum DNA damage signaling and the Akt signaling pathway, e.g. a common target for both pathways. A possibly novel property of Akt in aggravating drug sensitivity may also be proposed.

Liposomal cisplatin combined with gemcitabine in pretreated advanced pancreatic cancer patients: a phase I-II study.

The present trial is a phase I-II study based on a new liposomal cisplatin (lipoplatin). Previous preclinical and clinical data (phase I pharmacokinetics) led to the investigation of a combined treatment modality involving lipoplatin and gemcitabine. The gemcitabine dose was kept standard at 1000 mg/m2 and the lipoplatin dose was escalated from 25 mg/m2 to 125 mg/m2. The treatment was administered to advanced pretreated pancreatic cancer patients who were refractory to previous chemotherapy which included gemcitabine. Lipoplatin at 125 mg/m2 was defined as dose limiting toxicity (DLT) and 100 mg/m2 as the maximum tolerated dose (MTD) in combination with 1000 mg/m2 of gemcitabine. Preliminary objective response rate data showed a partial response in 2/24 patients (8.3%), disease stability in 14 patients (58.3%) for a median duration of 3 months (range 2-7 months) and clinical benefit in 8 patients (33.3%). Liposomal cisplatin is a non-toxic alternative agent to bare cisplatin. In combination with gemcitabine, it has an MTD of 100 mg/m2 and shows promising efficacy in refractory pancreatic cancer.

Liposomal oxaliplatin in the treatment of advanced cancer: a phase I study.

BACKGROUND: Lipoxal is a liposomal oxaliplatin, which reduces the cytotoxic agent's adverse reactions without reducing effectiveness. Our objectives were to determine the adverse reactions, dose-limiting toxicity (DLT) and the maximum tolerated dose (MTD) of lipoxal. PATIENTS AND METHODS: Twenty-seven patients with advanced disease of the gastrointestinal system were included in the study. All patients had been pretreated with standard chemotherapy according to established guidelines. At entry, all patients had recurrent or progressive disease (stage IV gastrointestinal cancers: colorectal, gastric and pancreatic). Six lipoxal dose levels (100 mg/m2, 150 mg/m2, 200 mg/m2, 250 mg/m2, 300 mg/m2 and 350 mg/m2) were set and at least 3 patients were included at each level. Eight patients were treated at 300 mg/m2 (MTD). The treatment was given once weekly for 8 weeks. RESULTS: No serious side-effects were observed at the first 4 dose levels (100-250 mg/m2). At levels 5 and 6, mild myelotoxicity and nausea were observed. The most common adverse reaction was grade 2-3 peripheral neuropathy, observed in all 4 patients treated at 350 mg/m2. The 350 mg/m2 dose level was therefore considered as DLT and the 300 mg/m2 level as the MTD. Of the 27 patients, 3 achieved partial response and 18 had stable disease for 4 months, (range 2-9 months). CONCLUSION: The most common toxicity was peripheral neuropathy at the 300 and 350 mg/m2 dose levels. Lipoxal was well-tolerated and greatly reduced all the other side-effects of oxaliplatin, especially myelotoxicity and gastrointestinal tract toxicities. These preliminary results showed adequate effectiveness in pretreated patients.

Pharmacokinetics and adverse reactions of a new liposomal cisplatin (Lipoplatin): phase I study.

Lipoplatin, a new liposomal cisplatin formulation, is formed from cisplatin and liposomes composed of dipalmitoyl phosphatidyl glycerol (DPPG), soy phosphatidyl choline (SPC-3), cholesterol and methoxy-polyethylene glycol-distearoyl phosphatidylethanolamine (mPEG2000-DSPE). Following intravenous infusion, the nanoparticles (110 nm) are distributed into tissues and concentrate preferentially at tumor sites supposedly via extravasation through the leaky tumor vasculature. This study was designed to investigate the pharmacokinetics and the toxicity of this new liposomal cisplatin in patients with pretreated advanced malignant tumors. The drug was infused for 8 h every 14 days at escalating doses. Twenty-seven patients were included and 3-5 patients were selected for each dosage level; levels started at 25 mg/m2 and were increased by 25 to 125 mg/m2. Three patients were also treated at higher dose levels, one each at 200, 250 and 300 mg/m2. Blood was taken at certain time intervals in order to estimate total platinum plasma levels. At level 5 (125 mg/m2), grades 1 and 2 GI tract and hematological toxicities were detected. No nephrotoxicity was observed. Seven additional patients were added at the 4th level (100 mg/m2) for further pharmacokinetic evaluation. Measurement of platinum levels in the plasma of patients as a function of time showed that a maximum platinum level is attained at 6-8 h. The half-life of Lipoplatin was 60-117 h depending on the dose. Urine excretion reached about 40% of the infused dose in 3 days. The data demonstrate that Lipoplatin up to a dose of 125 mg/m2 every 14 days has no nephrotoxicity and it lacks the serious side effects of cisplatin.

Systemic Lipoplatin infusion results in preferential tumor uptake in human studies.

Lipoplatin, a liposomal formulation of cisplatin, was developed with almost negligible nephrotoxicity, ototoxicity and neurotoxicity, as demonstrated in preclinical and Phase I human studies. A polyethylene-glycol coating of the liposome nanoparticles is supposed to result in tumor accumulation of the drug by extravasation through the altered tumor vasculature. We explored the hypothesis that intravenous infusion of Lipoplatin results in tumor targeting in four independent patient cases (one with hepatocellular adenocarcinoma, two with gastric cancer and one with colon cancer) who underwent Lipoplatin infusion followed by a prescheduled surgery approximately 20 h later. Direct measurement of the platinum levels in specimens from the excised tumors and normal tissues showed that the total platinum levels were on average 10-50 times higher in malignant tissue compared to the adjacent normal tissue specimens; most effective targeting was observed in colon cancer, with an accumulation up to 200-fold higher in colon tumors compared to normal colon tissue. Of the several surgical specimens, gastric tumors displayed the highest levels of total platinum suggesting Lipoplatin as a candidate anticancer agent for gastric tumors; gastric tumor specimens had up to 260 micrograms platinum /g tissue, that was higher than any tissue level in animals treated at much higher doses. Fat tissue displayed a high accumulation of total platinum in surgical specimens in three different patients, correlating to the lipid capsule of cisplatin in its Lipoplatin formulation. It was also inferred that normal tissue had more platinum trapped in the tissue but not reacted with macromolecules, whereas tumor tissue displayed platinum that reacted with cellular macromolecules; the data were consistent with a model where Lipoplatin damages more tumor compared to normal cells. In conclusion, Lipoplatin has the ability to preferentially concentrate in malignant tissue both of primary and metastatic origin following intravenous infusion to patients. In this respect, Lipoplatin emerges as a very promising drug in the arsenal of chemotherapeutics.

Safety and efficacy of quadrapeutics versus chemoradiation in head and neck carcinoma xenograft model.

Chemoradiation is the strongest anti-tumor therapy but in resistant unresectable cancers it often lacks safety and efficacy. We compared our recently developed cell-level combination approach, quadrapeutics, to chemoradiation therapy to establish pre-clinical data for its biodistribution, safety and efficacy in head and neck squamous cell carcinoma (HNSCC), as a clinically challenging aggressive and resistant cancer. In vitro and in vivo models of four carcinomas were treated with standard chemoradiation and quadrapeutics using identical drug and radiation doses. We applied liposomal cisplatin or doxorubicin, colloidal gold, near-infrared laser pulses and radiation, all at low safe doses. The final evaluation used a xenograft model of HNSCC. Quadrapeutics enhanced standard chemoradiation in vitro by reducing head and neck cancer cell proliferation by 1000-fold, inhibiting tumor growth in vivo by 34-fold and improving animal survival by 5-fold, and reducing the side effects to a negligible level. In quadrapeutics, we observed an "inversion" of the drug efficacy of two standard drugs: doxorubicin, a low efficacy drug for the cancers studied, was two times more efficient than cisplatin, the first choice drug in clinic for HNSCC. The radical therapeutic gain of quadrapeutics resulted from the intracellular synergy of the four components employed which we administered in a specific sequence, while the reduction in the toxicity was due to the low doses of all four components. The biodistribution, safety and efficacy data for quadrapeutics in HNSCC ensure its high translational potential and justify the possibility of clinical trials.

Viral and non-viral vectors in gene therapy: technology development and clinical trials.

Gene therapy as part of modern molecular medicine holds great promise for the treatment of both acute and chronic diseases and has the potential to bring a revolutionary era to cancer treatment. Gene therapy has been named the medicine of the future. For the past 10 years various viral and non-viral vectors have been engineered for improved gene and drug delivery. Although various diseases have been targeted, cancer therapy has been addressed to a large extent because of the straight forward approach. Delivery of toxic or immunostimulatory genes by viral and non-viral vectors has been investigated and encouraging results have been obtained in animal models. A large number of clinical trials have been conducted with some highly promising outcome. We propose that combinations of viruses with liposomes or polymers will solve the problem of systemic viral delivery and tumor targeting, bringing a revolution in molecular medicine and in applications of gene therapy in humans.

Low toxicity and anticancer activity of a novel liposomal cisplatin (Lipoplatin) in mouse xenografts.

Cisplatin has been one of the most widely used and most effective cytotoxic agents in the treatment of malignancies but causes severe adverse reactions including nausea/vomiting, renal toxicity, gastrointestinal toxicity, peripheral neuropathy, asthenia, and ototoxicity. A liposomal formulation of cisplatin, Lipoplatin, was developed in order to reduce the systemic toxicity of cisplatin. A single treatment of rats with 30 mg/kg Lipoplatin resulted in no toxicity whereas 2 or 3 weekly administrations at 30 mg/kg to rats gave neutropenia but no nephrotoxicity. On the contrary, a single injection to rats of 5 mg/kg cisplatin resulted in severe nephrotoxicity. Thus, Lipoplatin is less toxic than cisplatin in rats. Intraperitoneal or intravenous injection of Lipoplatin to SCID (severe combined immunodeficient) mice with subcutaneous breast MCF-7 or prostate LNCaP human tumors resulted in size reduction of the tumors; histological examination of the treated tumors in xenografts was consistent with apoptosis in tumor cells; thus, Lipoplatin appears to exert its cytotoxic effects to tumors in a mechanism similar to that of cisplatin. The preclinical studies reported here set the foundation for the clinical use of Lipoplatin as an exciting new drug with lower toxicity than cisplatin, endowed with proapoptotic properties.

Recent clinical trials using cisplatin, carboplatin and their combination chemotherapy drugs (review).

Cisplatin continues to play a central role in cancer chemotherapy in spite of its toxicity. It is used as first-line chemotherapy against epithelial malignancies of lung, ovarian, bladder, testicular, head and neck, esophageal, gastric, colon and pancreatic but also as second- and third-line treatment against a number of metastatic malignancies including cancers of the breast, melanoma, prostate, mesothelioma, leiomyosarcomas, malignant gliomas and others. Cisplatin has become the gold standard treatment against cervical cancer in combination with radiotherapy. This review summarizes the state of the art on clinical trials published mainly in 2002 using cisplatin and carboplatin in their combinations with other anticancer drugs. For most advanced cancers the response rate to chemotherapy is about 50% in first-line treatments and about 15% in second- or third-line treatments; for example response rates of 25-50% have been observed for chemonaive patients with advanced non-small cell lung cancer treated with cisplatin or carboplatin in combination with gemcitabine or taxanes and in exceptional cases these rates are up to 80% with addition of radiotherapy. Response rates are very discouraging in second- or third-line chemotherapy treatments (7-25%). Despite an increase in response rate from the use of modern-day chemotherapy drugs, no major difference in long-term survival has been achieved. It is a high priority to invent novel approaches for cancer treatment. It is hoped that a fraction of the numerous experimental drugs will show virtues in the anticancer arena especially combined with existing treatment regimens. Efforts should focus on diminution of side effects improving the quality of life of the patient. A preferential tumor targeting of chemotherapy treatments would bring a revolution in molecular medicine and would greatly advance cancer therapy in the upcoming years.

Cisplatin and platinum drugs at the molecular level. (Review).

Over twenty years of intensive work toward improvement of cisplatin, and with hundreds of platinum drugs tested, has resulted in the introduction of the widely used carboplatin and of oxaliplatin used only for a very narrow spectrum of cancers. A number of interesting platinum compounds including the orally administered platinum drug JM216, nedaplatin, the sterically hindered platinum(II) complex ZD0473, the trinuclear platinum complex BBR3464, and the liposomal forms Lipoplatin and SPI-77 are under clinical evaluation. This review summarizes the molecular mechanisms of platinum compounds for DNA damage, DNA repair and induction of apoptosis via activation or modulation of signaling pathways and explores the basis of platinum resistance. Cisplatin, carboplatin, oxaliplatin and most other platinum compounds induce damage to tumors via induction of apoptosis; this is mediated by activation of signal transduction leading to the death receptor mechanisms as well as mitochondrial pathways. Apoptosis is responsible for the characteristic nephrotoxicity, ototoxicity and most other toxicities of the drugs. The major limitation in the clinical applications of cisplatin has been the development of cisplatin resistance by tumors. Mechanisms explaining cisplatin resistance include the reduction in cisplatin accumulation inside cancer cells because of barriers across the cell membrane, the faster repair of cisplatin adducts, the modulation of apoptotic pathways in various cells, the upregulation in transcription factors, the loss of p53 and other protein functions and a higher concentration of glutathione and metallothioneins in some type of tumors. A number of experimental strategies to overcome cisplatin resistance are at the preclinical or clinical level such as introduction of the bax gene, inhibition of the JNK pathway, introduction of a functional p53 gene, treatment of tumors with aldose reductase inhibitors and others. Particularly important are combinations of platinum drug treatments with other drugs, radiation and the emerging gene therapy regimens.

Low renal toxicity of lipoplatin compared to cisplatin in animals.

Cisplatin is one of the most widely used and effective chemotherapeutic agents for the treatment of several human malignancies. Although the effectiveness of cisplatin is high, its toxicities justify the demand for improved formulations of this drug. A liposomal formulation of cisplatin, Lipoplatin, was developed in order to reduce the systemic toxicity of cisplatin. Mice and rats injected with cisplatin developed renal insufficiency with clear evidence of tubular damage, but those injected with the same dose of Lipoplatin were almost completely free of kidney injury. The maximum levels of total platinum in rat kidneys after intraperitoneal bolus injection of cisplatin or Lipoplatin at similar doses were similar, but the steady state accumulation of total platinum in the kidney was 5 times higher for cisplatin compared to Lipoplatin. This is proposed as one mechanism to explain the low renal toxicity of Lipoplatin.

Preparation, biodistribution and neurotoxicity of liposomal cisplatin following convection enhanced delivery in normal and F98 glioma bearing rats.

The purpose of this study was to evaluate two novel liposomal formulations of cisplatin as potential therapeutic agents for treatment of the F98 rat glioma. The first was a commercially produced agent, Lipoplatin™, which currently is in a Phase III clinical trial for treatment of non-small cell lung cancer (NSCLC). The second, produced in our laboratory, was based on the ability of cisplatin to form coordination complexes with lipid cholesteryl hemisuccinate (CHEMS). The in vitro tumoricidal activity of the former previously has been described in detail by other investigators. The CHEMS liposomal formulation had a Pt loading efficiency of 25% and showed more potent in vitro cytotoxicity against F98 glioma cells than free cisplatin at 24 h. In vivo CHEMS liposomes showed high retention at 24 h after intracerebral (i.c.) convection enhanced delivery (CED) to F98 glioma bearing rats. Neurotoxicologic studies were carried out in non-tumor bearing Fischer rats following i.c. CED of Lipoplatin™ or CHEMS liposomes or their "hollow" counterparts. Unexpectedly, Lipoplatin™ was highly neurotoxic when given i.c. by CED and resulted in death immediately following or within a few days after administration. Similarly "hollow" Lipoplatin™ liposomes showed similar neurotoxicity indicating that this was due to the liposomes themselves rather than the cisplatin. This was particularly surprising since Lipoplatin™ has been well tolerated when administered intravenously. In contrast, CHEMS liposomes and their "hollow" counterparts were clinically well tolerated. However, a variety of dose dependent neuropathologic changes from none to severe were seen at either 10 or 14 d following their administration. These findings suggest that further refinements in the design and formulation of cisplatin containing liposomes will be required before they can be administered i.c. by CED for the treatment of brain tumors and that a formulation that may be safe when given systemically may be highly neurotoxic when administered directly into the brain.

Concurrent liposomal cisplatin (Lipoplatin), 5-fluorouracil and radiotherapy for the treatment of locally advanced gastric cancer: a phase I/II study.

PURPOSE: Liposomal drugs have a better tolerance profile and are highly accumulated in the tumor environment, properties that promise an optimal radiosensitization. We investigated the feasibility of the combination of 5-fluorouracil/lecovorin-based radio-chemotherapy with the administration of high weekly dose of a liposomal platinum formulation (Lipoplatin). METHODS AND MATERIALS: Lipoplatin was given at a dose of 120 mg/m(2)/week, 5-fluorouracil at 400mg/m(2)/week (Day 1), whereas radiotherapy was given through 3.5-Gy fractions on Days 2, 3, and 4. Two groups of 6 patients received four and five consecutive cycles, respectively. RESULTS: Minimal nephrotoxicity (18.2% Grade 1) and neutropenia (9% Grade 3) was noted. Fatigue Grade 2 appeared in 25% of cases. Abdominal discomfort was reported by 18% of patients. No liver, kidney, gastric, or intestinal severe acute or late sequellae were documented, although the median follow-up of 9 months is certainly too low to allow safe conclusions. A net improvement in the performance status (from a median of 1 to 0) was recorded 2 months after the end of therapy. The response rates assessed with computed tomography, endoscopy, and biopsies confirmed 33% (2 of 6) tumor disappearance in patients treated with four cycles, which reached 80% (4 of 5) in patients receiving five cycles. CONCLUSIONS: Lipoplatin radio-chemotherapy is feasible, with minor hematological and nonhematological toxicity. The high complete response rates obtained support the testing of Lipoplatin in the adjuvant postoperative or preoperative radio-chemotherapy setting for the treatment of gastric cancer.

Clinical overview on Lipoplatin: a successful liposomal formulation of cisplatin.

Nanoparticle formulations for packaging existing drugs have been used to treat cancer. Lipoplatin is a liposomal cisplatin encapsulated into liposome nanoparticles of an average diameter of 110 nm. Lipoplatin has substantially reduced the renal toxicity, peripheral neuropathy, ototoxicity, myelotoxicity as well as nausea/vomiting and asthenia of cisplatin in Phase I, II and III clinical studies with enhanced or similar efficacy to cisplatin. During clinical development, 10- to 200-fold higher accumulation of Lipoplatin in solid tumors compared to adjacent normal tissue was found in patients. Targeting of tumor vasculature by Lipoplatin in animals suggested its antiangiogenesis potential and Lipoplatin was proposed to act like a double-sword: as chemotherapy and an antiangiogenesis drug. Lipoplatin has finished successfully one Phase III non-inferiority clinical study as first-line against NSCLC in its combination with paclitaxel showing statistically significant reduction in nephrotoxicity; two more Phase III studies are in progress, one in NSCLC with gemcitabine also showing noninferiority with reduced toxicity and another in squamous cell carcinoma of the head and neck with 5-fluorouracil. A registrational Phase II/III study against pancreatic cancer is in progress under the orphan drug status granted to Lipoplatin by the European Medicines Agency. Phase II studies are continuing in advanced breast cancer with vinorelbine and gastrointestinal cancers with radiotherapy and 5-fluorouracil. The highlights of the clinical development of Lipoplatin are reviewed.

MLH1-deficient tumor cells are resistant to lipoplatin, but retain sensitivity to lipoxal.

Lipoplatin, currently under phase III evaluation, is a novel liposomal cisplatin formulation highly effective against cancers. Lipoplatin has eliminated or reduced the systemic toxicity frequently seen for cisplatin. The objective of the present study was to determine whether the cytotoxic effect of lipoplatin is dependent on the functional integrity of DNA mismatch repair (MMR), a post-replicative DNA repair machinery implicated in cell cycle control and apoptosis. Clonogenic data revealed a significant (P<0.05) 2-fold resistance to lipoplatin of HCT116 human colorectal adenocarcinoma cells lacking MLH1, one of five proteins crucial to MMR function, as compared to MLH1-expressing HCT116 cells. In addition, MLH1-deficient cells were at least 3-fold less susceptible to apoptosis (DNA fragmentation) than MLH1-proficient cells. However, proteolytic processing of caspase-3, caspase-7 and poly(ADP-ribose)polymerase-1 following lipoplatin treatment was comparable in MLH1-deficient cells and -proficient cells. Furthermore, MLH1-deficient cells retained the ability to attenuate cell cycle progression past the G2/M checkpoint following lipoplatin treatment. In conclusion, our results indicate that the lipoplatin-sensitive phenotype of MLH1-proficient cells correlated with increased apoptosis which may occur via caspase-independent pathways. They also suggest that the integrity of MMR function is a relevant determinant accounting for the cytotoxicity of lipoplatin. However, this does not seem to apply to lipoxal, a novel liposomal formulation of oxaliplatin, because MLH1-deficient cells were as sensitive to lipoxal as MLH1-proficient cells.