Chemosensitivity of various peritoneal cancer cell lines to HIPEC and PIPAC: comparison of an experimental duplex drug to standard drug regimens in vitro.

We performed an in-vitro study testing the chemosensitivity of peritoneal cancer cell lines (SW620, HCT116, MKN45, 23,132/87, OAW42) to various cytostatic drug regimens. A duplex drug, characterized by reversible linking of the antimetabolites 2'-deoxy-5-fluorouridine (5-FdU) and 3'-C-ethynylcytidine (ECyd), was compared to oxaliplatin or to cisplatin plus doxorubicin. The experiments were designed to reflect the conditions of intraperitoneal chemotherapy. CASY® (Cell Analysis System) technology was used to compare the impact of incubation temperature/duration and drug concentration on the viability of the cancer cell lines versus normal human dermal fibroblasts. Two incubation scenarios were explored: (i) hyperthermic intraperitoneal chemotherapy (HIPEC) with 1 h of incubation at 42 °C, and (ii) pressurized intraperitoneal aerosol chemotherapy (PIPAC) with several successive incubations at 37 °C. Under HIPEC conditions, oxaliplatin induced a potent temperature-dependent growth inhibition of colon cancer cells not seen with the duplex drug. Under PIPAC conditions, the duplex drug achieved the same growth inhibition at a fraction of the dose level required with oxaliplatin. Gastric and ovarian cancer cells were more sensitive to cisplatin plus doxorubicin than to the duplex drug under PIPAC conditions. The duplex drug suggests itself, notably in cases of platinum resistance, as an alternative or addition to intraperitoneal chemotherapies when platinum-based PIPAC technology is used. Using it with HIPEC technology is not recommended. Higher doses of the duplex drug will enhance growth inhibition, albeit at the cost of a severely reduced difference in chemosensitivity between tumor and normal cells. Our findings provide orientation for PIPAC-based personalized intraperitoneal chemotherapy.

Pharmacodynamics of Oxaliplatin-Derived Platinum Compounds During Hyperthermic Intraperitoneal Chemotherapy (HIPEC): An Emerging Aspect Supporting the Rational Design of Treatment Protocols.

BACKGROUND: Hyperthermic intraperitoneal chemotherapy (HIPEC) is used to treat peritoneal surface malignancies with application of cytostatic drugs such as oxaliplatin (OX) after cytoreductive surgery. Despite its increased use, evidence for optimal drug dosage, and notably duration of HIPEC, is scarce. METHODS: In this study, OX distribution was comprehensively assessed in nine patients during HIPEC (300 mg OX/m2 body surface area in Physioneal solution for 30 min). Oxaliplatin and its derivatives were measured in peritoneal perfusates over time by liquid chromatography coupled with mass spectrometry (LC-MS), and the resulting total platinum concentration in tissue was analyzed by atomic absorption spectrometry. Additionally, a novel impedance-based real-time cytotoxicity assay was used to evaluate the bioactivity of perfusates ex vivo. RESULTS: Compared with amounts of OX expected in peritoneal perfusates by calculation, only 10-15% of the parent drug could be detected by LC-MS during HIPEC. Notably, the study additionally detected platinum compounds consistent with OX transformation, accounting for a further fraction of the applied drug. The cytotoxic properties of perfusates remained unchanged during HIPEC, with only a slight but significant attenuation evidenced after 30 min. CONCLUSIONS: The bioactivity of peritoneal perfusates ex vivo is a useful parameter for evaluating the actual cytotoxic potential of OX and its derivatives used in HIPEC over time, overcoming important limitations and disadvantages associated with respective drug monitoring only. Ex vivo cytotoxicity assays may be a promising tool to aid guiding future standardization and harmonization of HIPEC protocols based on drug-mediated effects.

Growth and Chemosensitivity of Gastric Adenocarcinoma and Non-Malignant Cell Lines in Response to Novel Anti-Cancer Drug Combinations.

BACKGROUND: To design novel polychemotherapy regimens for gastric adenocarcinoma therapy with wider therapeutic windows using a novel duplex drug (D-D). METHODS: Two gastric adenocarcinoma (MKN-45 and 23132/87) and 2 non-malignant (NHDF and CCL-241) cell lines were treated with different drug regimens that included different doses of the standard triple-drug combination epirubicin (E) + cisplatin (C) + 5-fluorouracil (5-FU, F), i.e. ECF, and a new D-D that combined 2'-deoxy-5-fluorouridine (5FdU) and 3'ethinylcytidine. The cells were cultured for 14 days and the effect of the drug combinations was evaluated using CASY cell counting technology. RESULTS: Overall growth inhibition of the cell lines with ECF was not cancer cell line-specific. Replacing 5-FU in ECF with a D-D resulted in greater growth inhibition of cancer cells than of the non-malignant cell lines and the inversion of the chemosensitivity of MKN-45 and 23132/87 cells. The type and quantity of the combined drug regimen determined the cytotoxicity and chemosensitivity of the cell lines. CONCLUSION: The cytotoxicity and tumour-cell specificity of standard single drugs can be markedly changed and determined using multidrug combinations that include D-Ds.

Sensitivity of gastric adenocarcinoma and normal cell lines against combined or conjugated antimetabolites.

The in-vitro growth inhibition of cancer and normal cell lines caused by mixed or covalently linked antimetabolites should clarify whether the conjugation of antimetabolites influences cell sensitivity and growth inhibition in a manner that differs from an equimolar mixture of the same antimetabolites or not. Growth inhibition of the human gastric adenocarcinoma cell lines 23132/87 and MKN-45 in comparison with normal gastric intestinal CCL-241 and the dermal fibroblast cell line NHDF was evaluated using CASY technology. The cell lines were incubated with an equimolar mixture of 5-fluoro-2'-deoxyuridine (5FdU)+3'-C-ethynylcytidine (ECyd) or the covalently linked duplex drug 5FdU(5'→5')ECyd. The drug and metabolites of the assays and medium were determined semiquantitatively using high-performance liquid chromatography. The sensitivity of cancer and nonmalignant cell lines was clearly different against the duplex drug. A measure of 0.65 µmol/l 5FdU(5'→5')ECyd, for example, reduced the growth of MKN-45 or 23132/87 gastric cancer cells from 100% on day 0 to about 50 or 20% on day 10, respectively. However, under the same conditions, the growth of the nonmalignant NHDF and CCL-241 cell lines was not markedly inhibited. The cytostatic activity of the duplex drug is based on the active metabolites in and outside the cell formed by the degradation of 5FdU(5'→5')ECyd. The sensitivity of cell lines against the duplex drug depended on its ability to metabolize the duplex drug. 5FdU(5'→5')ECyd should be more advantageous for specific and efficient polychemotherapy of gastric cancer than the corresponding equimolar mixture of 5FdU+ECyd or a standard combination regime of single drugs.

Cytostatic activity of a 5-fluoro-2'-deoxyuridine-alendronate conjugate against gastric adenocarcinoma and non-malignant intestinal and fibroblast cell lines.

BACKGROUND: 5-Fluoro-2'-deoxyuridine (5-FdU), a drug against gastric cancer, was covalently linked via its nucleobase with the amino-bisphosphonate alendronate (Ale), resulting in a new antimetabolite-bisphosphonate conjugate (5-FdU-Ale), designed for bone-targeting. MATERIALS AND METHODS: The cytostatic effect of 5-FdU-Ale was evaluated in vitro compared to monomers and mixtures using CASY Technologies and the human gastric adenocarcinoma cell lines 23132/87 and MKN-45, in comparison to the intestinal CCL-241 and dermal fibroblast NHDF neonatal cell lines. RESULTS: The adenocarcinoma cell lines demonstrated a slightly higher sensitivity, with respect to the cell lines CCL-241 and NHDF, to incubation with 5-FdU-Ale. In comparison to 5-FdU, 5-FU and an equimolar mixture of Ale+5-FdU and Ale+5-FU, the cytostatic activity of the 5-FdU-Ale was markedly reduced. CONCLUSION: 5-FdU-Ale was only partially or not at all metabolized to a mixture of cytostatic metabolites in vitro. Therefore an in vivo evaluation of the conjugates is indicated.

Cytostatic activity of the duplex drug linking 2'-deoxy-5-fluorouridine (5FdU) with 3'-C-ethynylcytidine (ECyd) against gastric adenocarcinoma cell lines.

The cytostatic potential of the new duplex drug 2'-deoxy-5-fluorouridylyl-(5'5')-3'-C-ethynylcytidine (5FdU(5'-5')ECyd) was evaluated in comparison to those of 5-fluorouracil (5FU), 2'-deoxy-5-fluorourindine (5FdU), 3'-C-ethynylycytidine (ECyd), cisplatin, an equimolar mixture of 5FdU + ECyd and a three component-mixture of 0.75 µM epirubicin/0.90 µM cisplatin/3.0 µM 5FU (ECF) by incubation of the two human gastric adenocarcinoma cell lines 23132/87 and MKN-45. The molar composition of ECF was taken from data of a triple combination chemotherapy for human gastric cancer. Time and dose depending inhibition of cell growth was determinated using the CASY technology. A growth decrease of both cell lines from 100% to about 20% was observed by treatment with ECF over a course of 14 days. This result provided basis to estimate the cytostatic potential of all tested drugs and combinations thereof. Corresponding high activities in respect to ECF were achieved by incubation of 23132/87 cells with single drugs 49 µM 5FU, 10 µM cisplatin, 3.4 µM 5FdU, 0.65 µM ECyd, the mixture 0.32 µM 5FdU + 0.32 µM ECyd and 0.32 µM 5FdU(5'-5')ECyd. The less sensitive MKN-45 cells require a 1.5-4 fold higher dose of the standard chemotherapeutics in order to achieve an equivalent cytostatic effect, in respect to the 23132/87 cell line,. However, the effect of the duplex drugs on MKN-45 cells was gained with a 5-fold lower dose than ECF. Due to its high cytostatic potential the duplex drug, which covalently links two active anticancer compounds, could be a new therapeutic alternative for chemotherapy in gastric cancer, currently treated with different combinations.

Everolimus interferes with the inflammatory phase of healing in experimental colonic anastomoses.

BACKGROUND: Delayed wound healing is a serious side effect of mTOR inhibitor-based immunosuppression after solid organ transplantation. The aim of this study was to test the hypothesis that the mTOR inhibitor everolimus interferes with the inflammatory phase of healing in experimental colonic anastomoses. MATERIALS AND METHODS: Thirty male Sprague-Dawley rats received a colonic anastomosis. Then, animals were randomized to three groups of daily treatment with either vehicle or everolimus in two different dosages (1.0mg/kg or 3.0mg/kg). After 7 d, rats were sacrificed, and mechanical, histologic, and biochemical parameters of intestinal healing were assessed. RESULTS: Anastomotic bursting pressure was significantly decreased by everolimus in both dosages, whereas hydroxyproline content was reduced only by the high everolimus dosage. Everolimus diminished cellular proliferation and new vessel growth. Furthermore, both quantity as well as quality of newly synthesized collagen fibers in the anastomotic granulation tissue was reduced. On the other hand, myeloperoxidase-positive (MPO) cells and interleukin-6 (IL-6) concentrations were increased, as was the activity of matrix-metalloproteinases MMP-2 and MMP-9. CONCLUSION: Everolimus interferes with the inflammatory phase of healing. However, it remains unclear whether this phenomenon is involved in everolimus impairment of experimental anastomotic repair.

Phosphoglycerate kinase 1 promoting tumor progression and metastasis in gastric cancer - detected in a tumor mouse model using positron emission tomography/magnetic resonance imaging.

BACKGROUND/AIMS: Tumor dissemination is frequent in gastric cancer and implies a poor prognosis. Cure is only achievable provided an accurate staging is performed at primary diagnosis. In previous studies we were able to show a relevant impact of increased phosphoglycerate kinase 1 expression (PGK1; a glycolytic enzyme) on invasive properties of gastric cancer in-vivo and in-vitro. Thus the aim of the present study was to evaluate the effect of enhanced PGK1 expression in gastric cancer employing magnetic resonance (MR)-imaging combined with positron emission tomography (PET), a recently emerging new high resolution imaging technique in a mouse model. METHODS: A metastatic nude mouse model simulating human gastric cancer behavior by orthotopic tumor implantation was established. Mice were divided into one control group (n=5) and two experimental groups (n=30) divided by half in animals baring tumors from MKN45-cells and MKN45-cells with plasmid-mediated overexpression of PGK1. In the course of tumor growth MR-imaging and PET/MRI fusion was performed. Successively experimental animals were examined macroscopically and histopathologically regarding growth, metastasis and PGK1 expression. RESULTS: Elevated PGK1 expression increased invasive and metastatic behavior of implanted gastric tumors significantly. MR/PET- imaging results in-vivoand subsequent ex-vivo findings concerning tumor growth and metastasis correlated excellently and could be underlined by concordant immuohistochemical PGK1 staining. CONCLUSION: Consistent in-vivo findings suggest that PGK1 might be crucially involved in gastric malignancy regarding growth and metastasis, which was also underlined by novel imaging techniques. Thus, PGK1 may be exploited as a prognostic marker and/or be of potential therapeutic value preventing malignant dissemination.

Effects of isoniazid and niacin on experimental wound-healing.

BACKGROUND: There is a need for effective treatments of ischemic wounds. Our aim was to test the hypothesis that systemic administration of isoniazid or niacin can enhance wound healing in ischemic as well as nonischemic tissues. METHODS: One 8-mm, full-thickness wound was made in a standardized, ischemic skin flap and 1 in adjacent nonischemic skin on the back of male Sprague-Dawley rats. Starting just after wounding, twice-daily intraperitoneal isoniazid (10 mg/kg b.i.d.), xanthinol nicotinate (30 mg/kg), or saline (control) were given for 14 days. Wound-healing was monitored by planimetry and oxygen tension in periphery of the wound using a microcatheter probe. Cellular proliferation in granulation tissue was assessed by immunohistochemical detection of proliferating cell nuclear antigen. The angiogenic activity of isoniazid and niacin was assessed using in vitro and ex vivo models. RESULTS: Although wound ischemia was evident by decreased oxygen tension (26 +/- 10 mmHg; n = 9) compared with the adjacent nonischemic wounds (51 +/- 8 mmHg; n = 8), neither compound significantly influenced intracutaneous oxygen tension. Isoniazid (P < .0001), but not niacin, promoted ischemic wound-healing even though both compounds increased proliferation measured on day 14 (P < .01). In normal wounds, the cumulative change in relative wound area over 14 days was increased by niacin (P = .002), but not by isoniazid, although both niacin (P = .011) and isoniazid (P = .036) increased cellular proliferation. Neither isoniazid nor niacin showed activity in either an endothelial tube formation assay or organotypic angiogenic assay under normoxic conditions. CONCLUSION: Isoniazid was capable of stimulating wound-healing in ischemic tissue to the level of nonischemic wounds and might offer a novel treatment option for wounds associated with arterial insufficiency. Although active in normal wounds, niacin did not promote ischemic wound-healing.