beta-cyclodextrin tetradecasulfate/tetrahydrocortisol +/- minocycline as modulators of cancer therapies in vitro and in vivo against primary and metastatic Lewis lung carcinoma

Enzymatic rationale and preclinical support for a potent protein kinase C beta inhibitor in cancer therapy

The macrocyclic bisindolylmaleimide, LY333531, selectively inhibits protein kinase C beta 1 and beta 2 isoforms with an approximate IC50 of 5 nanomolar. The efficacy of LY333531 administered alone and in combination with cytotoxic cancer therapies in models of non-small cell lung carcinoma and brain tumors was determined in vivo. In the Lewis lung carcinoma, administration of LY333531 enhanced the activity of paclitaxel and fractionated radiation and, to a lesser degree, carboplatin and gemcitabine. In the human T98G glioblastoma multiforme xenograft, the addition of LY333531 to treatment with carmustine (BCNU) resulted in enhanced tumor response in a nodule grown subcutaneously and increased life-span in animals bearing an intracranial tumor from 37 days in the control animals to 64 days in the BCNU treated animals, and to 104 days in the LY333531 plus BCNU treated animals with 4 out of 5 animals being long-term survivors.

The rationale and future potential of angiogenesis inhibitors in neoplasia

Malignant tumours are angiogenesis-dependent diseases. Several experimental studies suggest that primary tumour growth, invasiveness and metastasis require neovascularisation. Tumour-associated angiogenesis is a complex multistep process under the control of positive and negative soluble factors. A mutual stimulation occurs between tumour and endothelial cells by paracrine mechanisms. Angiogenesis is necessary, but not sufficient, as the single event for tumour growth. There is, however, compelling evidence that acquisition of the angiogenic phenotype is a common pathway for tumour progression, and that active angiogenesis is associated with other molecular mechanisms leading to tumour progression. Experimental research suggests that it is possible to block angiogenesis by specific inhibitory agents, and that modulation of angiogenic activity is associated with tumour regression in animals with different types of neoplasia. The more promising angiosuppressive agents for clinical testing are: naturally occurring inhibitors of angiogenesis (angiostatin, endostatin, platelet factor-4 and others), specific inhibitors of endothelial cell growth (TNP-470, thalidomide, interleukin-12 and others), agents neutralising angiogenic peptides (antibodies to fibroblast growth factor or vascular endothelial growth factor, suramin and analogues, tecogalan and others) or their receptors, agents that interfere with vascular basement membrane and extracellular matrix [metalloprotease (MMP) inhibitors, angiostatic steroids and others], antiadhesion molecules antibodies such as antiintegrin alpha v beta 3, and miscellaneous drugs that modulate angiogenesis by diverse mechanisms of action. Antiangiogenic therapy is to be distinguished from vascular targeting. Gene therapy aimed to block neovascularisation is also a feasible anticancer strategy in animals bearing experimental tumours. Antiangiogenic therapy represents one of the more promising new approaches to anticancer therapy and it is already in early clinical trials. Because angiosuppressive therapy is aimed at blocking tumour growth indirectly, through modulation of neovascularisation, antiangiogenic agents need to be developed and evaluated as biological response modifiers. Therefore, adequate and well designed clinical trials should be performed for a proper evaluation of antiangiogenic agents, by determination and monitoring of surrogate markers of angiogenic activity.

Preclinical studies of the combination of angiogenic inhibitors with cytotoxic agents

TNP-740, minocycline, suramin and genistein have demonstrated antiangiogenic activity in various experimental systems. The effect of these agents alone and in two agent combinations on the number of intratumoral vessels and response to cytotoxic anticancer therapies was assessed in animals bearing the Lewis lung carcinoma. Treatment with each of the antiangiogenic agents alone and in two agent combinations decreased the number of intratumoral vessels visualized by CD31 or Factor VIII staining to 30% to 50% of the number in the untreated control tumors. In general, the antiangiogenic agents are more effective adjuvants to cytotoxic therapies when used as two agent combinations than as single agents. The most effective antiangiogenic combinations were: TNP-470/minocycline > TNP-470/genistein > TNP-470/suramin. The increases in the response of the primary tumor to cyclophosphamide, adriamycin, CDDP, BCNU, x-rays or 5-fluorouracil and the lung metastases occur to about the same level with the addition of antiangiogenic agents to the therapies. With the treatment combination TNP-470/minocycline/cyclophosphamide 40% of the animals were cured. The results of these studies indicate that antiangiogenic agents can be very useful additions to treatment regimens for solid tumors.

Pharmaceutical applications of cyclodextrins. 2. In vivo drug delivery

The objective of this Review is to summarize and critique recent findings and applications of both unmodified and modified cyclodextrins for in vivo drug delivery. This review focuses on the use of cyclodextrins for parenteral, oral, ophthalmic, and nasal drug delivery. Other routes including dermal, rectal, and pulmonary delivery are also briefly addressed. This Review primarily focuses on newer findings concerning cyclodextrin derivatives which are likely to receive regulatory acceptance due to improved aqueous solubility and safety profiles as compared to the unmodified cyclodextrins. Many of the applications reviewed involve the use of hydroxypropyl-beta-cyclodextrins (HP-beta-CDs) and sulfobutylether-beta-cyclodextrins (SBE-beta-CDs) which show promise of greater safety while maintaining the ability to form inclusion complexes. The advantages and limitations of HP-beta-CD, SBE-beta-CD, and other cyclodextrins are addressed.

Interaction of interleukin-11 with cytotoxic therapies in vitro against CEM cells and in vivo against EMT-6 murine mammary carcinoma

Interleukin-11(rhIL-11) is a cytokine that has been shown to enhance the recovery of bone marrow and intestinal crypt cells after cytotoxic insult with radiation or anticancer drugs. The current study examined the effects of rhIL-11 on the response of CEM human lymphoblastic leukemia cells and on the EMT-6 murine mammary carcinoma in vivo to cytotoxic anticancer therapies. Exposure of CEM cells to rhIL-11 for 24 hr did not alter the cytotoxicity of melphalan or radiation, increased the cytotoxicity of CDDP (100 muM) and 4-hydroperoxycyclophosphamide (50 betaM) and decreased the cytotoxicity of 5-fluorouracil and ara-C toward the cells. Treatment of mice bearing the EMT-6 tumor with rhIL-11 twice daily for 4 days prior to and the day of cytotoxic therapy resulted in no significant change in the tumor cell killing or bone marrow CFU-GM killing by melphalan, cyclophosphamide, thiotepa, CDDP, radiation, 5-fluorouracil or ara-C. Administration of rhIL-11 twice per day on days 7-18 to EMT-6 tumor bearing animals receiving high dose chemotherapy (melphalan, thiotepa or cyclophosphamide) as a single dose on day 7 followed by mobilized peripheral blood cells on day 8 and rhG-CSF on days 8-20, tended to prolong the tumor growth delay produced by the drugs. This rhIL-11 treatment also resulted in a more rapid recovery of white blood cells and granulocytes in the animals. Furthermore, animals treated with rhIL-11 had improved survival rates compared with animals receiving all other normal tissue support without rhIL-11.

Influence of an anti-angiogenic treatment on 9L gliosarcoma: oxygenation and response to cytotoxic therapy

Tissue oxygen tensions were measured in subcutaneously growing rat 9L gliosarcoma under normal air and carbogen breathing conditions prior to and after i.v. administration of a perflubron emulsion. When these animals were treated with the anti-angiogenic agents TNP-470 and minocycline for 5 days prior to oxygen measurement, tumor hypoxia was decreased compared with untreated tumors. Hypoxia, defined as the percent of pO2 readings < or = 5 mm Hg, was decreased from 71% in untreated air-breathing controls to 34% in animals treated with the anti-angiogenic agents, the perflubron emulsion and carbogen breathing. These effects were manifest in the increased response of the tumor to single-dose (10, 20 and 30 Gy) radiation therapy. Twenty-four hours after treatment with BCNU oxygenation of the tumors was not altered; however, 24 hr after administration of adriamycin oxygenation of the tumors was increased such that hypoxia in adriamycin-treated tumors in animals receiving the perflubron emulsion and carbogen was reduced to 21%. Tumor growth delay in the s.c. tumors was increased by the addition of treatment with the anti-angiogenic agents from day 4 through day 18 post-tumor cell implantation along with BCNU or adriamycin on days 7-11. Administration of the perflubron emulsion and carbogen breathing resulted in increased tumor growth delay with the chemotherapeutic agents alone and in combination with the anti-angiogenic agents. Life span in animals bearing intracranially implanted 9L gliosarcoma progressively increased with administration of the anti-angiogenic agents and then the anti-angiogenic agents and perflubron emulsion/carbogen compared to treatment with BCNU or adriamycin.

Potentiation of cytotoxic therapies by TNP-470 and minocycline in mice bearing EMT-6 mammary carcinoma

The ability of the antiangiogenic agents TNP-470 and minocycline, singly or in combination, to potentiate the antitumor effects of several cytotoxic therapies was assessed in the murine EMT-6 mammary carcinoma as well as in two drug resistant sublines of that tumor designated EMT-6/CTX and EMT-6/CDDP. The antiangiogenic agents alone or in combination did not alter the growth of the tumors. However, their administration along with cyclophosphamide, CDDP, or thiotepa substantially increased the tumor growth delay produced by these cytotoxic therapies in tumors responsive to the drugs--the increase was about 2-fold for TNP-470 and minocycline together. In drug resistant tumors, treatment with the antiangiogenic agents did not reverse drug resistance but did increase the effect of the cytotoxic drugs. Treatment with TNP-470/minocycline also increased the oxygenation of each of the three tumors. Thus, TNP-470/minocycline administration increased the efficacy of fractionated radiation therapy, especially when used along with a perflubron emulsion oxygen delivery agent/carbogen. These results indicate that treatment regimens including therapies directed toward the proliferating normal cells within a tumor mass as well as therapies directed toward the malignant cells can produce improved outcomes.