Novel Hydrophilic Camptothecin Derivatives Conjugated to Branched Glycerol Trimer Suppress Tumor Growth without Causing Diarrhea in Murine Xenograft Models of Human Lung Cancer.

Camptothecin possesses broad antitumor spectra on various cancers. In spite of its marked tumor-suppressing potency, camptothecin is too hydrophobic to be solved in water and therefore not currently in clinical use. CPT-11 (irinotecan) is one of the hydrophilic analogues of camptothecin and widely prescribed. However, its water solubility is still low and furthermore evokes severe diarrhea. Therefore, we designed and synthesized novel highly hydrophilic camptothecin derivatives by conjugating SN38 with branched glycerol trimer (SN38-BGL), which we have been developing as a unique strategy to endow hydrophobic molecule with much hydrophilicity, to maximize the benefit of CPT-11 and minimize the adverse effects. The SN38-BGLs exhibited equivalent or slightly stronger tumor-suppressing effects in murine xenograft human lung cancer models compared to CPT-11. However, neither early- nor late-onset diarrhea was observed when SN38-BGL was administered. Heights of villi in jejunum and ileum were bigger than those from CPT-11-treated mice, indicating that SN38-BGL is less harmful than CPT-11. Ex vivo digestion by liver microsome did not yield SN38 but a couple of other molecules against our expectations, which suggests the involvement of other active metabolites than SN38 and may explain the differences. Hence, SN38-BGLs can be a novel hydrophilic camptothecin derivative without causing severe diarrhea.

Antitumor effect of novel anti-podoplanin antibody NZ-12 against malignant pleural mesothelioma in an orthotopic xenograft model.

Podoplanin (aggrus) is highly expressed in several types of cancers, including malignant pleural mesothelioma (MPM). Previously, we developed a rat anti-human podoplanin mAb, NZ-1, and a rat-human chimeric anti-human podoplanin antibody, NZ-8, derived from NZ-1, which induced antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity against podoplanin-positive MPM cell lines. In this study, we showed the antitumor effect of NZ-1, NZ-8, and NZ-12, a novel rat-human chimeric anti-human podoplanin antibody derived from NZ-1, in an MPM orthotopic xenograft SCID mouse model. Treatment with NZ-1 and rat NK (CD161a(+) ) cells inhibited the growth of tumors and the production of pleural effusion in NCI-H290/PDPN or NCI-H226 orthotopic xenograft mouse models. NZ-8 and human natural killer (NK) (CD56(+) ) cells also inhibited tumor growth and pleural effusion in MPM orthotopic xenograft mice. Furthermore, NZ-12 induced potent ADCC mediated by human MNC, compared with either NZ-1 or NZ-8. Antitumor effects were observed following treatment with NZ-12 and human NK (CD56(+) ) cells in MPM orthotopic xenograft mice. In addition, combined immunotherapy using the ADCC activity of NZ-12 mediated by human NK (CD56(+) ) cells with pemetrexed, led to enhanced antitumor effects in MPM orthotopic xenograft mice. These results strongly suggest that combination therapy with podoplanin-targeting immunotherapy using both NZ-12 and pemetrexed might provide an efficacious therapeutic strategy for the treatment of MPM.

A local application of recombinant human fibroblast growth factor 2 for tibial shaft fractures: A randomized, placebo-controlled trial.

Fibroblast growth factor 2 (FGF-2) is a potent mitogen for mesenchymal cells, and a local application of recombinant human FGF-2 (rhFGF-2) in a gelatin hydrogel has been reported to accelerate bone union in our animal studies and preparatory dose-escalation trial on patients with surgical osteotomy. We have performed a randomized, double-blind, placebo-controlled trial in which patients with fresh tibial shaft fractures of transverse or short oblique type were randomly assigned to three groups receiving a single injection of the gelatin hydrogel containing either placebo or 0.8 mg (low-dosage group) or 2.4 mg (high-dosage group) of rhFGF-2 into the fracture gap at the end of an intramedullary nailing surgery. Of 194 consecutive patients over 2 years, 85 met the eligibility criteria, and 70 (24 in the placebo group and 23 each in low- and high-dosage groups) completed the 24-week study. The cumulative percentages of patients with radiographic bone union were higher in the rhFGF-2-treated groups (p = .031 and .009 in low- and high-dosage group, respectively) compared with the placebo group, although there was no significant difference between low- and high-dosage groups (p = .776). At 24 weeks, 4, 1, and 0 patients in the placebo, low-dosage, and high-dosage groups, respectively, continued to show delayed union. No patient underwent a secondary intervention, and the time to full weight bearing without pain was not significantly different among the three groups (p = .567). There also was no significant difference in the profiles of adverse events among the groups. In conclusion, a local application of the rhFGF-2 hydrogel accelerated healing of tibial shaft fractures with a safety profile.

Local application of recombinant human fibroblast growth factor-2 on bone repair: a dose-escalation prospective trial on patients with osteotomy.

Based on preclinical evidence in animal models, the present study examined the clinical efficacy and safety of recombinant human fibroblast growth factor-2 (rhFGF-2) to accelerate bone repair in a dose-escalation prospective trial. One of three dosages (200, 400 or 800 microg) of rhFGF-2 in a biodegradable gelatin hydrogel was injected during surgery into the osteotomy site of 59 knee osteoarthritis patients undergoing high tibial osteotomy, and 57 of them were monitored for 16 weeks. The rhFGF-2 dose dependently increased the percentage of patients with radiographic bone union, and decreased the average time needed for such union. The percentages of patients with an absence of pain and full-weight bearing were also greater in the higher dosage groups than in the low dosage group, especially in the clinically critical periods 6, 8, and 10 weeks. Neither blood chemistries nor clinical adverse events were associated with the rhFGF-2 dosages. We therefore conclude that the rhFGF-2 in gelatin hydrogel dose dependently accelerated radiographic bone union of a surgical osteotomy with a safety profile at least at the dosages used, suggesting the clinical efficacy of this agent for bone repair.

Transient exposure of fibroblast growth factor-2 induced proliferative but not destructive changes in mouse knee joints.

Fibroblast growth factor-2 (FGF-2) has the potential to regenerate damaged articular cartilage tissue due to its exerting anabolic effects on chondrocytes. However, FGF-2 is involved in pathogenesis of rheumatoid arthritis, where the joint is destructed. The study aims at clarifying the effects of FGF-2 on joints. When radiolabeled FGF-2 was injected into knee joints of C57Bl/10 mice, a transient binding was observed in the superficial and intermediate zones of the articular cartilage as well as in the synovium and perichondrium. An FGF-2 injection (5 microg) caused synovial hyperplasia adjacent to the articular cartilage on day 7, cartilage formation adjacent to the articular cartilage on day 14, and osteophyte on day 21. The intensity of safranin-O staining of the articular cartilage increased on day 14. These changes were dose-dependent. No destructive changes in the joints were observed. In a joint, transient exposure of FGF-2 caused proliferative changes, but not destructive changes.