Tissue platinum after clinical treatment with cisplatin or carboplatin in tumor-bearing patients

Tissue platinum (Pt) levels were measured in tumor-bearing patients treated with either cisplatin or carboplatin. Cisplatin was given by intra-arterial, intraperitoneal, and intravenous (iv) administrations. After death, vertebrae and intervertebral disks were removed from eight human subjects, and livers and kidneys were removed from the half of them. When cisplatin was administered intraperitoneally, Pt of the liver was higher than that of the kidney, and a high content of Pt was detected in the vertebra by comparing with the other administration methods. At the intra-arterial administration of cisplatin, Pt was mainly accumulated in the kidney. At the iv administration of cisplatin, a high level of Pt was found in the vertebra and intervertebral disk, especially at the highest value at 10.31 μg/g in the intervertebral disk of one case, whereas a low level of Pt was detected in the liver. On the contrary, it was found that the iv administration of carboplatin did not result in high accumulations of Pt in the liver, kidney, intervertebral disk, and vertebra. Therefore, Pt is accumulated in different organs, depending on the way cisplatin is administered, but Pt is accumulated least in them by the administration of carboplatin.     

Haemolytic anaemia after cisplatin treatment.

Normochromic or normocytic anaemia is a common side effect of treatment with cisplatin. Two patients treated with cisplatin 100 mg/m2 in combination with vinblastine, bleomycin, and actinomycin D developed haemolytic anaemia. Neither patient had evidence of haemolysis before treatment, and in both cases severe haemolytic anaemia developed after several courses of cisplatin and when the cancer had regressed almost completely. The importance of haemolysis in the development of anaemia after cisplatin treatment has not been investigated fully and further studies are needed.     

Retained platinum uptake and indifference to p53 status make novel transplatinum agents active in platinum-resistant cells compared to cisplatin and oxaliplatin

Despite the clinical success of platinum-containing drugs in the treatment of solid tumors, acquired resistance remains a major obstacle. We previously identified a group of novel transplanaramine or transplatinum compounds based on distinct activity profiles in the NCI-60 panel. In the present study, parental KB-3.1 cells with wild-type p53 and its cisplatin- and oxaliplatin-resistant sublines harboring mutant p53 proteins were used to contrast several transplatinum compounds with cisplatin and oxaliplatin. The transplatinum compounds retained cytotoxic activity in the resistant cell lines. While intracellular accumulation and DNA platination of cisplatin and oxaliplatin was decreased in the resistant cells, the transplatinum compounds both accumulated intracellularly and platinated DNA at comparable levels in all cell lines. Cytoflow analysis confirmed that cisplatin and oxaliplatin alter the cell cycle distribution and result in apoptosis; however, at comparably toxic concentrations, the transplatinum compounds did not alter the cell cycle distribution. Analysis of the cytoplasmic fraction treated with acetone showed that cisplatin and oxaliplatin readily bound to macromolecules in the pellet, whereas a larger percentage of the transplatinum compounds remained in the supernatant. We concluded that, distinct from platinum compounds currently in use, transplatinum compounds accumulate intracellularly in resistant cells at levels comparable to those in drug-sensitive cells, do not affect the cell cycle and thus retain cytotoxicity independent of p53 status and likely have cytoplasmic targets that are important in their activity.     

Retained platinum uptake and indifference to p53 status make novel transplatinum agents active in platinum-resistant cells compared to cisplatin and oxaliplatin

Despite the clinical success of platinum-containing drugs in the treatment of solid tumors, acquired resistance remains a major obstacle. We previously identified a group of novel transplanaramine or transplatinum compounds based on distinct activity profiles in the NCI-60 panel. In the present study, parental KB-3.1 cells with wild-type p53 and its cisplatin- and oxaliplatin-resistant sublines harboring mutant p53 proteins were used to contrast several transplatinum compounds with cisplatin and oxaliplatin. The transplatinum compounds retained cytotoxic activity in the resistant cell lines. While intracellular accumulation and DNA platination of cisplatin and oxaliplatin was decreased in the resistant cells, the transplatinum compounds both accumulated intracellularly and platinated DNA at comparable levels in all cell lines. Cytoflow analysis confirmed that cisplatin and oxaliplatin alter the cell cycle distribution and result in apoptosis; however, at comparably toxic concentrations, the transplatinum compounds did not alter the cell cycle distribution. Analysis of the cytoplasmic fraction treated with acetone showed that cisplatin and oxaliplatin readily bound to macromolecules in the pellet, whereas a larger percentage of the transplatinum compounds remained in the supernatant. We concluded that, distinct from platinum compounds currently in use, transplatinum compounds accumulate intracellularly in resistant cells at levels comparable to those in drug-sensitive cells, do not affect the cell cycle and thus retain cytotoxicity independent of p53 status and likely have cytoplasmic targets that are important in their activity.     

Interaction of cisplatin and DNA-targeted 9-aminoacridine platinum complexes with DNA

Interaction of acridine- and 9-aminoacridinecarboxamide platinum complexes with DNA was investigated with respect to their DNA sequence specificity and kinetics of binding. The DNA sequence specificity of the compounds was quantitatively analyzed using a polymerase stop assay with the plasmid pUC19. The 9-aminoacridinecarboxamide platinum complexes exhibited a different sequence specificity to that of cisplatin, shifted away from runs of consecutive guanines (the main binding site for cisplatin). This alteration was dependent on chain length. Shorter chain length compounds (n = 2, 3) showed a greater difference in sequence specificity, while longer chain length compounds (n = 4, 5) more closely resembled cisplatin. An acridinecarboxamide platinum complex showed a similar sequence specificity to cisplatin, revealing that the major change of sequence specificity was due to the presence of the 9-amino substituent. A linear amplification system was used to investigate the time course of the reaction. The presence of an intercalating group (acridinecarboxamide or 9-aminoacridinecarboxamide) greatly increased the rate of reaction with DNA; this is proposed to be due to a different reaction mechanism with DNA (direct displacement by the N-7 of guanine).     

Renal metallothionein and platinum levels in diabetic and nondiabetic rats injected with cisplatin

This study was designed to investigate the relationship between the attenuation of cisplatin-induced nephrotoxicity in experimental diabetes and the increased level of renal metallothionein (MT) reported to occur in this condition. Two groups of male Sprague-Dawley rats were used: 42-day streptozotocin diabetics and age-matched nondiabetics. Half of each group was injected with a nephrotoxic dose of cisplatin (5 mg/kg, ip) and half with vehicle. Four hours after injection, renal MT and platinum (Pt) content were quantified. Mean renal MT concentration in vehicle-injected diabetics was about triple that found in nondiabetics. Comparison of renal MT concentrations in cisplatin-injected diabetics and nondiabetics with their vehicle-injected counterparts suggested an inducing effect of the drug. In contrast to the marked elevations of MT in diabetic kidney, mean renal Pt concentration in the cisplatin-injected diabetic group was only about one-fourth that of the nondiabetic group. No difference was evident in the intracellular distribution Pt between cytosolic and particulate fractions from diabetic and nondiabetic kidneys. It was concluded that: (i) Sequestration of Pt by MT cannot account for the resistance of diabetic kidney to cisplatin toxicity. (ii) Rather, the resistance is due to a significant decrease in renal uptake/retention of cisplatin or derivatives during the critical first few hours after injection.     

Enhanced DNA-PK-mediated RPA2 hyperphosphorylation in DNA polymerase eta-deficient human cells treated with cisplatin and oxaliplatin

The chemotherapeutic drugs cisplatin and oxaliplatin act by induction of DNA damage, including monoadducts, intrastrand and interstrand crosslinks. An increased understanding of the repair and replication of platinum-damaged DNA is required to improve the effectiveness of these drugs in killing cancer cells. We have investigated the effect of expression of DNA polymerase eta (poleta), a translesion synthesis (TLS) enzyme, on the response of human cell lines to cisplatin and oxaliplatin. Poleta-deficient cells are more sensitive to both drugs than are normal cells. In poleta-deficient cells, drug treatment leads to prolonged S-phase arrest, and increased phosphorylation of the phosphatidylinositol-3-kinase-related protein kinase (PIKK) substrates Chk1, p95/Nbs1 and RPA2, the 34kDa subunit of replication protein A. Cisplatin- and oxaliplatin-induced hyperphosphorylation of RPA2, and association of the hyperphosphorylated protein with chromatin, is elevated in poleta-deficient cells. Cisplatin-induced phosphorylation of RPA2 on serine 4/serine 8, but not on serine 33, is inhibited by the DNA-PK inhibitor, NU7441, but not by the ATM inhibitor, KU-55933. Cisplatin-induced DNA-PK-dependent hyperphosphorylation of RPA2 on serine 4/serine 8 occurs after recruitment of RPA to chromatin, as determined by immunofluorescence and by subcellular fractionation. ATR is required both for recruitment of RPA2 to chromatin and its subsequent hyperphosphorylation on serine 4/serine 8 by DNA-PK, since CGK733, an inhibitor of ATM and ATR, blocked both recruitment and hyperphosphorylation. Thus, increased sensitivity to cisplatin and oxaliplatin in DNA poleta-deficient cells is associated with prolonged S-phase arrest, and enhanced PIKK-signalling, in particular activation of DNA-PK-dependent hyperphosphorylation of RPA2 on serines 4 and 8.     

Adhesion of blood platelets to collagen and fibrinogen after treatment with cisplatin and its complex with glutathione

Cisplatin (cis-diamminedichloroplatinum II, CDDP) is one of the most widely used chemotherapy drugs. Unfortunately, it induces serious side effects such as haematological toxicity. The aim of the present study was to evaluate the effect of CDDP on the first step in blood platelet activation-platelet adhesion, induced by thrombin or adenosine diphosphate (ADP), to collagen and fibrinogen. The action of cisplatin was compared with the action of cisplatin glutathione complex (GS-Pt) on platelet adhesion and on free radical generation measured by chemiluminescence. Pretreatment of blood platelets with cisplatin (0.1-20 microM) caused a dose- and time-dependent reduction of platelet adhesion to collagen and fibrinogen (p <0.05). The GS-Pt complex (20 microM, 30 min) had a stronger inhibitory effect on this process. Moreover, the complex (R2 = 0.992; p <0.05) also stimulated the chemiluminescence of blood platelets to a greater extent than CDDP alone (R2 = 0.999; p <0.01). The results suggest that inhibition of platelet adhesion in the presence of cisplatin and its complex with glutathione correlates with the generation of reactive oxygen species in these cells.     

Hematotoxicity and blood glutathione levels after cisplatin treatment of tumor-bearing mice

The involvement of glutathione, a major cellular antioxidant, in cisplatin-mediated development of various hematological changes in mice bearing ascites Dalton lymphoma tumor was investigated. With tumor growth, glutathione levels decreased in blood but increased in tumor cells. Cisplatin treatment of tumor-bearing mice caused a decrease in glutathione levels in blood, ascites supernatant, and tumor cells. Blood hemoglobin, erythrocytes, packed cell volume and leukocytes (eosinophils, basophils, and lymphocytes) were also decreased along with the development of various morphological abnormalities in erythrocytes (microcytes, macrocytes, echinocytes, acanthocytes, etc.) after cisplatin treatment. All these hematotoxic features were noted to be increased more when buthionine sulfoximine (a specific glutathione-depleting agent) was also given prior to cisplatin treatment. However, combination treatment of cysteine (precursor for glutathione synthesis) plus cisplatin resulted in an improvement in the glutathione levels and decrease in hematological toxicities. It is noted that the glutathione levels in blood and abnormalities in erythrocytes and other hematological parameters are inversely related in cisplatin-mediated cancer chemotherapy. It is suggested that blood glutathione may play an important role in the development of cisplatin-mediated hematological toxicity in the host. This revised version was published online in July 2006 with corrections to the Cover Date.     

Long-term treatment with antiandrogens

Since the first report in 1966 by Scott and Schirmer on the clinical use of antiandrogens in patients with prostatic cancer, several studies have been published. Most of these deal with short-term treatment and include only a limited number of patients.

Steroid antiandrogens have demonstrable progestational and antigonadotrophic effects, whereas the non-steroid “pure” antiandrogens mainly act peripherally on androgen-dependent accessory genital organs and thus preserve libido and sexual potency in most patients.

Short-term treatment with antiandrogens have exerted responses similar to those achieved with conventional endocrine therapy. Because of relatively fewer side effects of these drugs, there is an increasing interest in assessment of the long-term effect, and some studies have been initiated.     

Long-term cisplatin exposure impairs autophagy and causes cisplatin resistance in human lung cancer cells

Cisplatin-based chemotherapy frequently resulted in acquired resistance of cancer cells. The underlying mechanism of such resistance is not fully understood especially the involvement of autophagy and autophagic cell death. This study thus investigated whether an alteration in autophagy could be responsible for cisplatin resistance in the long-term exposure lung carcinoma cells. The cisplatin resistant clone (H460/cis) of H460 cells was established by exposing the cells with gradually increasing concentrations of cisplatin until chemoresistance acquisition was elucidated by MTT, Hoechst 33342 staining and comet assays. Degree of autophagosome formation and level of LC3 marker were evaluated by acridine orange and western blot analysis, respectively. H460/cis cells exhibited irregular shape with ~3-fold resistant to cisplatin-induced apoptosis compared with H460 cells. Proteins analysis for LC3 indicated that the levels of LC3 in resistant cells were significantly lower than those in H460 cells. Moreover, autophagosome formation detected by acridine orange staining was dramatically reduced in the resistant cells, suggesting the role of autophagy in attenuating of cisplatin-induced cell death. Further, co-treatment of cisplatin with autophagy inducer, trifluorperazine, could resensitize H460/cis cells to cisplatin-induced cell death. Our findings reveal the novel mechanisms causing cisplatin resistance in lung carcinoma cells after long-term drug exposure regarding autophagy.     

Changes in glutathione-related enzymes in tumor-bearing mice after cisplatin treatment

The effect of cisplatin on five glutathione-related enzymes was studied in liver, kidney, and Dalton lymphoma cells of tumor-bearing mice. In liver, the activities of glutathione S-transferase, glutathione peroxidase, catalase, and superoxide dismutase decreased approximately 30–40%, 60–67%, 35–50% and 70–80% respectively, while glutathione reductase increased about 36–45% after cisplatin treatment. In kidney, catalase activity decreased by 47–82% at all time points (24–96 h) of cisplatin treatment, while glutathione S-transferase activity decreased significantly (~24%) mainly at 72 h of treatment. An increase in glutathione reductase (~1.5–2.5 times), glutathione peroxidase (significant at 24 h, 47%), and superoxide dismutase (~15–60%) was noted in kidney after the treatment. In Dalton lymphoma cells, the activities of glutathione S-transferase, glutathione peroxidase, and catalase decreased very distinctly (~2–5, 2–5 and 5–11 times, respectively) at all time points, but glutathione reductase decreased significantly only at 72 h of cisplatin treatment. Interestingly, the superoxide dismutase activity in Dalton lymphoma cells increased initially at 24–48 h and then decreased (~60%) during later periods (72–96 h) of treatment. Cisplatin treatment caused a decrease in glutathione level in Dalton lymphoma cells (~14–20%) and kidney (~18–28%) but no change in liver. In view of the results, a definite correlation with the changes in glutathione concentrations and enzymatic activities in a tissue could not be firmly derived. It is suggested that the changes in various glutathione-related enzymes and glutathione levels in the tissues of the host during cisplatin-mediated chemotherapy could affect cellular antioxidant defense potential, which may play an important contributory role in cisplatin-mediated toxicity, particularly nephrotoxicity, and anticancer activity in the host. This revised version was published online in July 2006 with corrections to the Cover Date.     

Long-term outcome after treatment of feline inappropriate elimination

Urination and defecation outside the litter box is one of the most common behavior problems reported by cat caretakers and the most common behavioral reason that results in the relinquishment of cats to shelters. A physical examination, laboratory tests, and a thorough behavioral history are necessary to differentiate between the diagnoses of disease, marking, and inappropriate elimination. This study followed up on the outcome of cats who were treated for inappropriate elimination. Fifty-eight caregivers completed a telephone questionnaire 12 to 54 months after treatment was initiated. Twenty-seven (47%) of caregivers felt their cat was cured, 15 (26%) felt their cat was much better, 8 (14%) slightly better, 6 (10%) the same, and 2 (3%) worse. Forty caregivers (67%) observed a 90% to 100% reduction in frequency. There was a significant association between the caregivers' perception of treatment outcome and percentage reduction in frequency. There was a significant association between caregivers compliance and outcome. The results of this study give caregivers a valid and promising alternative to relinquishment for inappropriate elimination problems.     

Immunocytochemical and in situ hybridization studies of gastrin after cisplatin treatment.

Cisplatin treatment (9 mg/kg) causes bloating of the stomach, an increase in gastric acid, and ulceration in rats. Gastrin, a gut peptide, plays an important role in regulating gastric acid production. To study the role of gastrin in this increased gastric acid production after cisplatin treatment, male Wistar rats (100-150 g) were treated with cisplatin (9 mg/kg) in five divided doses over 5 consecutive days. The rats were sacrificed 1, 6, 10, or 15 days after the last treatment. As measured by immunocytochemistry, in situ hybridization, Northern blot, and dot-blot techniques, gastrin was found to be below detectable limits just 1 day after cisplatin treatment. However, 10-15 days after the last injection, the levels for both gastrin and its mRNA gradually recovered to normal. Northern blot studies showed that decreased somatostatin mRNA parallels the changes of gastrin and its mRNA. These results suggest that after cisplatin treatment the increased gastric acid production in rat stomach is independent of gastrin. This decrease of gastrin production is not under the influence of somatostatin, which also decreased after cisplatin treatment.     

Accumulation of platinum in the intervertebral discs and vertebrae of ovarian tumor-bearing patients treated with cisplatin

Platinum was determined by the inductively coupled plasma mass spectrometry (ICP-MS) in the intervertebral discs and vertebrae of ovarian tumor bearing patients treated withcis-diamminedichloro-platinum (II) (cisplatin). Platinum was 0.05 ng/mL at the absolute detection limit, and platinum was undetectable in the intervertebral discs and vertebrae of human specimens without cisplatin treatments. On the other hand, platinum was detected in the intervertebral discs and vertebrae of patients administered cisplatin, and platinum concentration was at levels of 1.06–10.31 μg/g dry tissue in the intervertebral discs and 0.60–1.28 μg/g dry tissue in the vertebrae, respectively. The platinum level of intervertebral discs was 4.3-fold higher than that of the vertebrae. Thus, platinum accumulates greatly in the intervertebral discs and somewhat in the vertebrae after administering cisplatin to patients for therapy.     

Efficient translesion replication past oxaliplatin and cisplatin GpG adducts by human DNA polymerase eta

Platinum anticancer agents form bulky DNA adducts which are thought to exert their cytotoxic effect by blocking DNA replication. Translesion synthesis, one of the pathways of postreplication repair, is thought to account for some resistance to DNA damage and much of the mutagenicity of bulky DNA adducts in dividing cells. Oxaliplatin has been shown to be effective in cisplatin-resistant cell lines and less mutagenic than cisplatin in the Ames assay. We have shown that the eukaryotic DNA polymerases yeast pol zeta, human pol beta, and human pol gamma bypass oxaliplatin-GG adducts more efficiently than cisplatin-GG adducts. Human pol eta, a product of the XPV gene, has been shown to catalyze efficient translesion synthesis past cis, syn-cyclobutane pyrimidine dimers. In the present study we compared translesion synthesis past different Pt-GG adducts by human pol eta. Our data show that, similar to other eukaryotic DNA polymerases, pol eta bypasses oxaliplatin-GG adducts more efficiently than cisplatin-GG adducts. However, pol eta-catalyzed translesion replication past Pt-DNA adducts was more efficient and less accurate than that seen for previously tested polymerases. We show that the efficiency and fidelity of translesion replication past Pt-DNA adducts appear to be determined by both the structure of the adduct and the DNA polymerase active site.     

Long-term survival results after treatment for oligometastatic brain disease

AimThe aim of this study was to characterize the survival results of patients with up to four brain metastases after intense local therapy (primary surgery or stereotactic radiotherapy) if extracranial metastases were absent or limited to one site, e.g. the lungs.BackgroundOligometastatic disease has repeatedly been reported to convey a favorable prognosis.Material and methodsThis retrospective study included 198 German and Norwegian patients treated with individualized approaches, always including brain radiotherapy. Information about age, extracranial spread, number of brain metastases, performance status and other variables was collected. Uni- and multivariate tests were performed.ResultsMedian survival was 16.5 months (single brain metastasis) and 9.8 months (2–4, comparable survival for 2, 3 and 4), respectively (p = 0.001). After 5 years, 15 and 2% of the patients were still alive. In patients alive after 2 years, added median survival was 23 months and the probability of being alive 5 years after treatment was 26%. In multivariate analysis, extracranial metastases were not significantly associated with survival, while primary tumor control was.ConclusionLong-term survival beyond 5 years is possible in a minority of patients with oligometastatic brain disease, in particular those with a single brain metastasis. The presence of extracranial metastases to one site should not be regarded a barrier towards maximum brain-directed therapy.