Berberine inhibits chemotherapy-exacerbated ovarian cancer stem cell-like characteristics and metastasis through GLI1.

Despite the remarkable clinical response in ovarian cancer therapy, the distinctively high metastasis rate is still a barrier to achieve satisfying prognosis. Our study aimed to decipher the role of berberine in inhibiting chemotherapy-exacerbated ovarian cancer metastasis. We found that chemotherapy exacerbated the migration and cancer stem cell (CSC)-like characteristics through transcriptional factor GLI1, which regulated the pluripotency-associated gene BMI1 and the epithelial-mesenchymal transition (EMT) markers Vimentin and Snail. Berberine could not only down-regulate CSC-like characteristics but also reverse EMT and migration through inhibiting chemotherapy-activated GLI1/BMI1 signaling pathway. Together, our study revealed the pivotal role of berberine in overcoming chemotherapy-exacerbated ovarian cancer metastasis, thereby provided a potential adjuvant therapeutic agent in combination with chemotherapeutics to prevent metastasis during ovarian cancer chemotherapy.

Protective effects of Nigella sativa oil against carboplatin-induced liver damage in rats.

OBJECTIVE: This study aimed to investigate the protective effects of nigella sativa oil (NSO) against liver damage due to intraperitoneal (i.p.) usage of carboplatin which is commonly used as a chemotherapeutic agent. MATERIAL AND METHOD: Twenty four female Wistar-albino rats (about 200-350 grams each) were divided into 4 groups. Group 1 (n = 6) was administered 4 ml/kg intraperitoneal (i.p.) saline 48 and 24 h before. Group 2 (n = 6) was i.p. administered 4 ml/kg NSO 48 h before and 4 ml/kg saline 24 h before. Group 3 (n = 6) was i.p. administered 4 ml/kg saline 48 h before and 80 mg/kg carboplatin 24 h before. Group 4 (n = 6) was i.p. administered 4 ml/kg NSO 48 h before and 80 mg/kg carboplatin 24 h before. At the end of 48 h, all rats were sacrificed, and liver tissues were put into 10% neutral formalin. After the routine tissue follow-up, histopathological changes and collagen fiber density were evaluated with Hematoxylin-Eosin and Masson's Trichrome staining. Apoptotic index was determined with TUNEL staining. RESULTS: The degeneration in hepatocytes, fiber distribution and density around central vein and portal space was observed in the carboplatin group compared to the control and NSO groups, hepatocyte cords preserved integrity, partial degeneration in hepatocytes and decreased collagen fiber distribution around central vein was noted in the NSO-carboplatin group compared to the carboplatin group. The apoptosis was lower in the NSO-carboplatin group compare with the carboplatin group, but no statistically significant difference was found between the two groups (p = 0.449). CONCLUSION: When used NSO before carboplatin exposure, it may protect against liver damage.

Selective Inner Hair Cell Dysfunction in Chinchillas Impairs Hearing-in-Noise in the Absence of Outer Hair Cell Loss.

Poorer hearing in the presence of background noise is a significant problem for the hearing impaired. Ototoxic drugs, ageing, and noise exposure can damage the sensory hair cells of the inner ear that are essential for normal hearing sensitivity. The relationship between outer hair cell (OHC) loss and progressively poorer hearing sensitivity in quiet or in competing background noise is supported by a number of human and animal studies. In contrast, the effect of moderate inner hair cell (IHC) loss or dysfunction shows almost no impact on behavioral measures of hearing sensitivity in quiet, when OHCs remain intact, but the relationship between selective IHC loss and hearing in noise remains relatively unknown. Here, a moderately high dose of carboplatin (75 mg/kg) that produced IHC loss in chinchillas ranging from 40 to 80 % had little effect on thresholds in quiet. However, when tested in the presence of competing broadband (BBN) or narrowband noise (NBN), thresholds increased significantly. IHC loss >60 % increased signal-to-noise ratios (SNRs) for tones (500-11,300 Hz) in competing BBN by 5-10 dB and broadened the masking function under NBN. These data suggest that IHC loss or dysfunction may play a significant role in listening in noise independent of OHC integrity and that these deficits may be present even when thresholds in quiet are within normal limits.

Carnitine deficiency aggravates carboplatin nephropathy through deterioration of energy status, oxidant/anti-oxidant balance, and inflammatory endocoids.

We have recently shown that carnitine deficiency could represent a risk factor in paracetamol hepatotoxicity. By the same token, d-carnitine-induced carnitine deficiency aggravated carboplatin nephropathy following challenge with a single dose (35mg/kg, IP) of the platinum drug in male Swiss albino rats. The combination modality induced marked degenerative changes and severe inflammation in kidney tissues that surpassed either carboplatin or d-carnitine given alone. The combined regimen synergistically increased the serum levels of creatinine, blood urea nitrogen (BUN), tumor necrosis factor alpha (TNF-alpha), palmitate, and kidney malondialdehyde (MDA), adenosine triphosphate (ATP), nitric oxide (NO) contents as well as kidney myeloperoxidase (MPO) activity. The only parameter that has been notably decreased was the kidney reduced glutathione (GSH) level. Exaggeration by carnitine deficit of the deleterious effects of carboplatin is most probably ascribed to energy starvation. The reduction in kidney content of ATP parcels was associated with elevation of serum palmitate level that reflected debilitated fatty acid oxidation, and this further deteriorated energy resources in kidney tissues. Compromising the oxidant/anti-oxidant balance and modulating the release of some inflammatory endocoids namely, TNF-alpha and NO could also possibly account for such combinatorial detrimental toxicity. The current study was further extended to elucidate any possible nephroprotective effects of l-carnitine. Interestingly, carnitine supplementation ahead of carboplatin challenge ameliorated and almost normalized all the biochemical parameters and also mitigated the injurious effects of the cytotoxic drug. Thus, one could conclude that carnitine deficiency, whether being a causative clue or a sequela, might represent a risk factor in carboplatin nephropathy.

Treatment results of continuous intra-arterial CBDCA infusion chemotherapy in combination with radiation therapy for locally advanced tongue cancer.

OBJECTIVE: The objective of this study was to improve the treatment results for locally advanced tongue cancer. A combination of radiotherapy with continuous intra-arterial therapy using CBDCA was used. STUDY DESIGN: According to TNM staging (1997), 29 patients had stage III lesions and 11 patients had stage IV (M0) lesions. A catheter was inserted through the lingual artery in 26 patients, through the external carotid artery in 11 patients, and through the faciolingual trunk in 2 patients. CBDCA was continuously infused for 4 to 6 weeks. With IA chemotherapy, external irradiation (median dose: 46.8 Gy) was simultaneously performed, and 1 to 2 courses of systemic chemotherapy were performed in 19 patients before intra-arterial chemotherapy. RESULTS: The 5-year local control rate was 65%. The 5-year OS rate was 39.5%. There were no clinically significant adverse side effects. CONCLUSION: Continuous IA CBDCA and concurrent radiation therapy can be delivered safely with good efficacy for locally advanced carcinoma of the tongue.

In vitro and in vivo suppression of growth of hepatocellular carcinoma cells by novel traditional Chinese medicine-platinum anti-cancer agents.

Protein phosphatase 2A (PP2A) is a new target for platinum (Pt)-based cancer chemotherapeutic agents. A series of novel Pt complexes containing demethylcantharidin, a modified component of a traditional Chinese medicine (TCM), [Pt(C8H8O5)(NH2R)2] 1-5 have been shown to inhibit PP2A both in its purified form and in cell homogenates. In this study, the potential efficacy of compounds 1-5 in suppressing the growth of PP2A-highly expressed liver cancer was evaluated. The in vitro anti-proliferative activity of compounds 1-5 was investigated in human hepatocellular carcinoma (HCC) cell lines using the MTT assay. Compounds 1-5 were about 2-20 and 20-200 times more potent than cisplatin and carboplatin, respectively, in SK-Hep1 and HepG2 cells. The in vivo anti-tumor efficacies of 1-5 were evaluated in a s.c. inoculated SK-Hep1 xenograft model in nude mice. Compounds 1-5 demonstrated definite in vivo activity (giving rise to an optimal %T/C as low as 14.5%) without inducing undue toxicity, contrasting the lack of activity of cisplatin and carboplatin. In a cisplatin-resistant model established in vivo in human HCC, compounds 1-5 could still elicit the same level of tumor growth suppression as in the control tumors, demonstrating the circumvention of cisplatin cross-resistance. An acute toxicity study in ICR mice showed that compounds 1-5 are not nephrotoxic at LD10. The high potency of the novel TCM-Pt compounds against liver cancer and the minimal toxicity suggest that they have significant potential to be developed into useful Pt-based anti-tumor drugs.

[Chronotherapy combining 5-fluorouracil, folinic acid and carboplatin as first line treatment in metastatic colorectal cancer. A phase 2 study]. / Chronothérapie associant le 5-fluorouracile, l'acide folinique, et le carboplatine en première ligne thérapeutique dans le cancer colorectal métastatique. Une étude de phase 2.

Seventy-two patients suffering from a metastatic colorectal cancer received, as first line treatment, a combination chronotherapy with 5-FU and folinic acid (infused from 10 pm to 10 am with a peak at 4 am, respectively at doses of 700 and 300 mg/m2 per day) and carboplatin (infused at the dose of 40 mg/m2 per day from 10 am to 10 pm with a peak at 4 pm). The courses of four days were repeated every two weeks. A major tumoral response was observed in 60% cases (68% in those not previously treated with adjuvant chemotherapy). The median times to progression and overall survival established at 11 and 27 months. The clinical (grades 3-4 in maximum 5% cases) and hematological (grades 3-4 in maximum 10-29% cases) toxicities were quite limited. Our observations suggest the interest to incorporate carboplatin in the combined infusional treatment of colorectal cancer.

[Adjuvant chemotherapy for Dukes B2 and C colon cancer combining 5-fluorouracil and folinic acid with or without carboplatin. Feasibility and comparison between standard and chronomodulated deliveries]. / Chimiothérapie adjuvante pour le cancer du colon de stades Dukes B2 et C comportant du 5-fluorouracile et de l'acide folinique, avec ou sans carboplatine. Faisabilité et comparaison d'une administration standard à une administration chronomodulée.

Thirty-seven patients operated from a Dukes B2-C colon cancer were randomised to receive as adjuvant infusional chemotherapy, nine 5 FU and folinic acid courses with or without carboplatin, as standard (de Gramont; 2 days every 2 weeks) or chronomodulated administration (4 days every 2 weeks). The overall tolerance was judged excellent with less than 7% courses with dose-adaptations. The two carboplatin arms presented an enhanced haematological toxicity, while some more cutaneous toxicity was observed in the chronomodulated arm with the three drugs.

L-Carnitine halts apoptosis and myelosuppression induced by carboplatin in rat bone marrow cell cultures (BMC).

Carboplatin (CP), a second generation platinum compound, is effective against various types of cancers, producing less nephrotoxicity and ototoxicity but more myelotoxicity than cisplatinum. CP-myelosuppression is the rate-limiting step of its clinical use. Prevention of CP-myelosuppression is a major target in the field of chemotherapy. Therefore, the present study investigates the use of L-carnitine (LCR)-an antioxidant, cardioprotective, neuroprotective, and immunostimulant nontoxic natural compound-to protect against CP-induced myelosuppression. The viability of BMC was studied using a trypan blue exclusion technique following incubation with CP and/or LCR as a function of time and concentration. Apoptosis was tested for by detecting the amount of DNA fragmentation and the visualization of DNA ladders upon gel electrophoresis. Bone marrow progenitor cell function was examined by colony forming unit assay. Cellular contents of glutathione (GSH) and malondialdehyde (MDA) were also estimated. Results revealed that LC50 of CP is 4.7 mM and the highest safe concentration of LCR is 5 mM. Co-exposure of LCR+CP rescued BMC viability by 37% compared to the CP-treated cultures. The LCR halts CP-induced apoptosis and it significantly improves the function of the bone marrow progenitors by increasing the number of colony-forming units as a response to granulocyte/macrophage colony stimulating factors. Finally, LCR restores CP-induced GSH depletion and prevents MDA elevation in BMC. In summary, the results suggest that LCR is able to protect against CP-induced myelosuppression, which suggests its use as an adjuvant therapy. This finding merits further investigation into the mechanism(s) of such protection as well as its interaction with CP antitumor activity.

Time response of carboplatin-induced nephrotoxicity in rats.

Carboplatin, a second-generation platinum-containing anti-cancer drug, is currently being used against human cancers. High-dose carboplatin chemotherapy can cause renal tubular injury in cancer patients. We have shown a dose-dependent nephrotoxicity of carboplatin in a rat model. However, the time response of carboplatin-induced renal injury has not been explored. This study investigated the time response of carboplatin-induced nephrotoxicity in rat. Male Wistar rats (250-300 g) were divided into two groups of 30 animals each and treated as follows: (1) control (saline, intraperitoneally) and (2) carboplatin (256 mg kg(-1), intraperitoneally). The animals (n = 6) from each group were sacrificed 1-5 days after treatment. The blood and kidneys were isolated and analyzed. Plasma creatinine, blood urea nitrogen (BUN), and blood urea levels were increased significantly in response to carboplatin in a time-dependent manner, indicating potential nephrotoxicity. Carboplatin time-dependently increased the renal platinum concentration, renal xanthine oxidase activity, increased membrane lipid peroxidation (MDA) concentration, while ratio of reduced-to-oxidized glutathione (GSH/GSSG) depleted significantly, indicating oxidative renal injury. Renal anti-oxidant enzymes, such as cytosolic copper/zinc-superoxide dismutase (CuZn-SOD) and mitochondrial manganese (Mn)-SOD, catalase (CAT), and glutathione peroxidase (GSH-Px) activities were decreased significantly due to carboplatin 3-5 days post-treatment. The protein expressions of renal CuZn-SOD and Mn-SOD significantly depleted 3-5 days after carboplatin administration, indicating decline in de novo synthesis of enzyme proteins. The data suggested that carboplatin caused time-dependent oxidative renal injury, as evidenced by renal anti-oxidant depletion, enhanced lipid peroxidation, platinum content, plasma creatinine BUN, and blood urea levels in rats.

Time response of carboplatin-induced hearing loss in rat.

Carboplatin is currently being used as an anticancer drug against human cancers. However, high dose of carboplatin chemotherapy resulted in hearing loss in cancer patients. We have shown that carboplatin-induced hearing loss was related to dose-dependent oxidative injury to the cochlea in rat model. However, the time response of ototoxic dose of carboplatin on hearing loss and oxidative injury to cochlea has not been explored. The aim of the study was to evaluate the time response of carboplatin-induced hearing loss and oxidative injury to the cochlea of the rat. Male Wistar rats were divided into two groups of 30 animals each and treated as follows: (1) control (normal saline, i.p.) and (2) carboplatin (256 mg/kg, a single i.p. bolus injection). Auditory brain-evoked responses (ABRs) were recorded before and 1-5 days after treatments. The animals (n = 6) from each group were sacrificed on day 1, 2, 3, 4, and 5 and cochleae were isolated and analyzed. Carboplatin significantly elevated the hearing thresholds to clicks and to 2, 4, 8, 16, and 32 kHz tone burst stimuli only 3-5 days post-treatment. Carboplatin significantly increased nitric oxide (NO), malondialdehyde (MDA) levels and manganese superoxide dismutase (Mn-SOD) activity in the cochlea 4-5 and 3-5 days post-treatment, respectively, indicating enhanced influx of free radicals and oxidative injury to the cochlea. Carboplatin significantly depressed the reduced to oxidized glutathione (GSH/GSSG) ratio, antioxidant enzyme activities such as copper/zinc-superoxide dismutase (CuZn-SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) as well as enzyme protein expressions in the cochlea 3-5 days after treatment. The data suggest that carboplatin-induced hearing loss involves oxidative injury to the cochlea of the rat in a time-dependent manner.

Carboplatin-induced oxidative injury in rat inferior colliculus.

Carboplatin is currently being used as an anticancer drug against human cancers. However, high dose of carboplatin chemotherapy resulted in ototoxicity in cancer patients. Carboplatin-induced ototoxicity was related to oxidative stress to the cochlea and inner hair cell loss in animals. It is likely that initial oxidative injury spreads throughout the neuroaxis of the auditory system later. The study aim was to evaluate carboplatin-induced hearing loss and oxidative injury to the central auditory system (inferior colliculus) of the rat. Male Wistar rats were divided into two groups of seven animals each and treated as follows: (1) control (normal saline, intraperitoneal [i.p.]) and (2) carboplatin (256 mg/kg, i.p.). Auditory brain-evoked responses (ABRs) were recorded before and 4 days after treatments. The animals were sacrificed on the 4th day and inferior colliculus from brain stem and cerebellum were isolated and analyzed. Carboplatin significantly elevated the hearing threshold shifts at clicks, 2-, 4-, 8-, 16-, and 32-kHz tone burst stimuli. Carboplatin significantly increased nitric oxide and lipid peroxidation, xanthine oxidase, and manganese superoxide dismutase activities in the inferior colliculus, but not in the cerebellum, indicating an enhanced flux of free radicals in the central auditory system. Carboplatin significantly depressed the reduced to oxidized glutathione ratio, antioxidant enzyme activities, such as copper-zinc superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, and glutathione S-transferase, and enzyme protein expressions in the inferior colliculus, but not in the cerebellum, 4 days after treatment. The data suggest that carboplatin induced oxidative injury specifically in the inferior colliculus of the rat leading to hearing loss.

Dose response of carboplatin-induced nephrotoxicity in rats.

Abstract: Carboplatin, a second-generation platinum-containing anticancer drug, is currently being used against a variety of cancers. High-dose carboplatin chemotherapy can cause renal tubular injury in cancer patients. However, the biochemical mechanism of carboplatin-induced renal injury has not been well studied. This study investigated the dose response of carboplatin-induced changes in endogenous antioxidants, lipid peroxidation and platinum content in rat kidney. Male Wistar rats (250-300 g) were divided into five groups and treated as follows: (1) control (saline, intraperitoneally); (2) carboplatin (64 mg/kg, intraperitoneally); (3) carboplatin (128 mg/kg, intraperitoneally); (4) carboplatin (192 mg/kg, intraperitoneally); and (5) carboplatin (256 mg/kg, intraperitoneally). The animals were sacrificed four days after treatment. The blood and kidneys were isolated and analyzed. Plasma creatinine and blood urea nitrogen levels were increased significantly in response to carboplatin in a dose-dependent manner. Renal superoxide dismutase and catalase activities were decreased significantly due to carboplatin at dosages of 128 mg/kg and above. The protein expressions of renal copper/zinc-superoxide dismutase and manganese-superoxide dismutase significantly depleted after carboplatin. Carboplatin (192 and 256 mg/kg) significantly increased lipid peroxidation (malondialdehyde concentration) in rat kidneys. Carboplatin dose-dependently increased the renal platinum concentration, with significance at dosages of 128 mg/kg and above. Carboplatin (256 mg/kg) significantly increased renal xanthine oxidase activity, while ratio of reduced to oxidized glutathione depleted significantly. The data suggested that carboplatin caused dose-dependent oxidative renal injury, as evidenced by renal antioxidant depletion, enhanced lipid peroxidation, platinum content, plasma creatinine and blood urea nitrogen levels in rats.

Drugs elevating extracellular adenosine promote regeneration of haematopoietic progenitor cells in severely myelosuppressed mice: their comparison and joint effects with the granulocyte colony-stimulating factor.

We tested capabilities of drugs elevating extracellular adenosine and of granulocyte colony-stimulating factor (G-CSF) given alone or in combination to modulate regeneration from severe myelosuppression resulting from combined exposure of mice to ionizing radiation and carboplatin. Elevation of extracellular adenosine was induced by joint administration of dipyridamole (DP), a drug inhibiting the cellular uptake of adenosine, and adenosine monophosphate (AMP), serving as an adenosine prodrug. DP+AMP, G-CSF or all these drugs in combination were administered in a 4-d treatment regimen starting on day 3 after induction of myelosuppression. Comparable enhancements of haematopoietic regeneration due to elevation of extracellular adenosine or to action of G-CSF were demonstrated as shown by elevated numbers of haematopoietic progenitor cells for granulocytes/macrophages (GM-CFC) and erythrocytes (BFU-E) in the bone marrow and spleen in early time intervals after termination of the drug treatment, i.e. on days 7 and 10 after induction of myelosuppression. Coadministration of all the drugs further potentiated the restoration of progenitor cell pools in the haematopoietic organs. The effects of the drug treatments on progenitor cells were reflected in the peripheral blood in later time intervals of days 15 and 20 after induction of myelosuppression, especially as significantly elevated numbers of granulocytes and less pronounced elevation of lymphocytes and erythrocytes. The results substantiate the potential of drugs elevating extracellular adenosine for clinical utilization in myelosuppressive states, e.g. those accompanying oncological radio- and chemotherapy.

Carboplatin-induced oxidative stress in rat cochlea.

Carboplatin is currently being used in the clinic against a variety of human cancers. However, high dose carboplatin chemotherapy resulted in ototoxicity in cancer patients. This is the first study to show carboplatin-induced oxidative stress response in the cochlea of rat. Male Wistar rats were divided into two groups of six animals each and treated as follows: (1) control (normal saline, i.p.) and (2) carboplatin (256 mg/kg, i.p.). Animals in both groups were sedated with ketamine/xylazine and auditory brainstem-evoked responses were recorded before and 4 days after treatments. The animals were sacrificed on the fourth day and cochleae were harvested and analyzed. A significant elevation of the hearing threshold shifts was noted at clicks, 8, 16, and 32 kHz tone burst stimuli following carboplatin administration. Carboplatin significantly increased nitric oxide and malondialdehyde levels, xanthine oxidase and manganese-superoxide dismutase activities in the cochlea indicating enhanced flux of free radicals. Cochlear glutathione levels, antioxidant enzyme activities such as copper zinc-superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glutathione S-transferase and enzyme protein levels were significantly depleted 4 days after carboplatin treatment. The data suggest that carboplatin induced free radical generation and antioxidant depletion, and caused oxidative injury in the cochleae of rats.

Cisplatin-based chemotherapy for postoperative recurrence in non-small cell lung cancer patients: relation of the in vitro chemosensitive test to clinical response.

The usefulness of the in vitro chemosensitivity test, the collagen gel droplet embedded culture drug- sensitivity test (CD-DST, Int J Oncol 11: 449, 1997), in cisplatin-based combined chemotherapy for postoperative recurrent tumors in non-small cell lung cancer (NSCLC) patients was retrospectively analyzed. CD-DST data for cisplatin (or carboplatin), etoposide, 5-fluorouracil, mitomycin C, and vindesine were obtained in 311 surgically resected primary lesions. Of them, 25 patients were practically treated with first-line cisplatin- or carboplatin-based chemotherapy for postoperative initial recurrence. Nine (36%) of them responded to the combined chemotherapy for recurrent lesions, including one with complete remission, whereas 16 did not, with no change in 5 and progression in 11. Seven (70%) of 10 patients receiving combined chemotherapy using two or three in vitro sensitive chemoagents showed good responses, whereas there was no responder among the patients receiving chemotherapy including no in vitro sensitive chemoagents. In particular, of 11 patients showing good sensitivity to cisplatin or carboplatin on CD-DST, 8 (73%) responded to chemotherapy, whereas only one (7%) of 14 patients showing cisplatin- or carboplatin-resistance on CD-DST was a responder. Thus, CD-DST results for the chemoagents, especially cisplatin or carboplatin, correlated with chemotherapeutic response, indicating that the CD-DST analysis of surgically resected primary NSCLC tumors is a practically useful indicator of the clinical effect of first-line cisplatin-based combined chemotherapy for postoperative recurrence.

Dose response of carboplatin-induced hearing loss in rats: antioxidant defense system.

Carboplatin, a platinum-containing anticancer drug, is currently being used against a variety of cancers. However, a single high dose of carboplatin is ototoxic in cancer patients. This is the first study to show carboplatin-induced hearing loss in a rat model. Male Wistar rats were divided into five groups and treated as follows: (1) control (saline, intraperitoneally (i.p.)); (2) carboplatin (64 mg/kg, i.p.); (3) carboplatin (128 mg/kg i.p.); (4) carboplatin (192 mg/kg, i.p.) and (5) carboplatin (256 mg/kg, i.p.). Animals in all groups were sedated with ketamine/xylazine and auditory brain-evoked responses (ABRs) were recorded before and 4 days after treatments. The animals were sacrificed on the fourth day and cochleae were harvested and analyzed. Carboplatin dose-dependently decreased body weight. However, at higher doses of carboplatin (192 and 256 mg/kg), there was a significant elevation of hearing threshold shifts at clicks, 4, 8, 16 and 32 kHz tone burst stimuli. The higher doses of carboplatin (192 and 256 mg/kg) significantly increased cochlear lipid peroxidation (132 and 146% of control) and depleted cochlear glutathione levels (66 and 63% of control), respectively. The antioxidant enzyme activities such as superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, and glutathione-S-transferase (GST) depressed significantly at higher doses of carboplatin. The data suggest that higher doses of carboplatin (above 128 mg/kg) induce hearing loss as evidenced by significant changes in ABRs, lipid peroxidation and antioxidants in the cochlea of rats.

Memorial lecture. Megakaryocytic growth factors: is there a new approach for management of thrombocytopenia in patients with malignancies?

C-mpl ligand acts primarily as a lineage-specific hematopoietic growth factor by promoting proliferation of megakaryocyte precursors and their differentiation into megakaryocytes and platelets. In addition to the ability of c-mpl ligand to support megakaryocytic development from CD34+ precursor cells, several lines of evidence also point to a stimulatory effect on hematopoietic stem cells. When recombinant thrombopoietin or pegylated megakaryocyte growth and development factor is administered to normal animals or humans, there is a dose-dependent increase in the platelet count. When administered following chemotherapy in animal models or humans, c-mpl ligands reduce the duration and sometimes the degree of thrombocytopenia. The issue of whether clinically relevant thrombocytopenia can be ameliorated has so far been more difficult to resolve. Because severe thrombocytopenia is not commonly seen with standard chemotherapy regimens, clinical studies examining c-mpl ligands for their ability to ameliorate chemotherapy-induced thrombocytopenia will focus on treatment of acute leukemias and bone marrow transplantation. The potential utility of c-mpl ligands for treatment of myelodysplastic syndromes, aplastic anemias, or in HIV infection, will have to be evaluated in the future. Possibly the greatest potential of thrombopoietic growth factors in the near future may be in transfusion medicine, to collect and to store platelets from healthy donors or in autologous settings.

Whole-body hyperthermia combined with ifosfamide and carboplatin causes hypotension and nephrotoxicity.

It was previously postulated on the basis of clinical data that the cardiovascular sequelae of extracorporeal whole-body hyperthermia (e-WBH), i.e., hypotension (which requires catecholamine support) results in unique nephrotoxicity in combination with select chemotherapeutic agents. In an attempt to explain this phenomenon, we mimicked e-WBH physiological conditions in a rat model. Animals were treated with and without ifosfamide (IFO) and/or carboplatin (CBDCA) at 37 degrees C or 41.5-41.8 degrees C, with blood pressure monitoring and catecholamine support comparable to the clinical setting. Ex vivo post-treatment data (24 h) from artificially perfused kidneys (i.e., histology, urine volume, perfusion rate, glomerular filtration rate, and the reabsorption of sodium, glucose, and water) demonstrated unique toxicity including proximal tubular necrosis for the combination of WBH and IFO, for WBH and CBDCA and for WBH and IFO plus CBDCA, but not for IFO and CBDCA without WBH. These data, considered together with results derived from a subsequent clinical trial and the laboratory work of others were consistent with the hypothesis.

Time dependency of hematopoietic growth factor coupled to chronotoxicity of carboplatin.

A growing body of data suggests that cancer therapy may be improved and toxicity reduced by administration of antineoplastic agents and cytokines at carefully selected times of the day. The time-dependent effects of each of the drugs have been documented, but not their mutual time dependencies. In the present studies we sought to determine the best time for granulocyte colony-stimulating factor (G-CSF) administration after carboplatin treatment. Carboplatin was injected in different groups of ICR mice at four different circadian stages for 5 consecutive days. Mice were synchronized with an alternation of 12 h of light (from 6:00 a.m. to 6:00 p.m.) and 12 h of darkness. After the last injection, peripheral WBCs of three mice from each group were counted every 4 h over a 24-h period. Bone marrow toxicity was estimated with the mean 24-h WBC count. The most severe leukopenia occurred in the group injected at 3:00 p.m. - 9 h after light onset. The second set of experiments evaluated the time-dependent effect of G-CSF when singly injected or given after carboplatin injections for 5 days only at 3:00 p.m. G-CSF was injected into various groups on days 8 and 9 at the same four different circadian stages. On the 10th day after the first injection, peripheral WBCs of three mice from each group were counted every 4 h over a 24-h period. Time-dependent effects were observed when G-CSF was injected as a single agent. When G-CSF was given at various times to the group with the most severe carboplatin-induced leukopenia, peripheral WBC count recovery was monitored at all injection times; it reached its highest level (exceeding even that of the control) when G-CSF was injected at 3:00 a.m. Dosing times of both chemotherapy and growth factor are relevant for optimization of carboplatin's hematologic tolerability.