Olav Kaalhus

Liposomal drug delivery appears to improve the antitumor effect and reduce toxicity compared with the free drug. The therapeutic index may be improved further by combining cytotoxic drugs and radiotherapy. Successful therapy requires that the cytotoxic agents reach the tumor cells. Therefore, we studied tumor growth and the microdistribution of liposomal doxorubicin (Caelyx) with and without additional ionizing radiation in human osteosarcoma xenografts in athymic mice. Caelyx was injected i.v. 1 day before single or fractionated radiotherapy. Both chemoirradiation regimens induced significant tumor growth delays and worked synergistically. Confocal laser scanning microscopy showed that intact liposomes were located in close proximity to endothelial cells, and the distribution of released doxorubicin was heterogeneous. Before radiotherapy, hardly any doxorubicin was localized in the central parts of the tumor. Radiotherapy increased the tumor uptake of doxorubicin by a factor of two to four, with drug being redistributed farther from the vessels in the tumor periphery and located around vessels in the central parts of the tumor. Colocalization of doxorubicin and hypoxic cells showed no distribution of drug into hypoxic areas. Dynamic contrast-enhanced magnetic resonance imaging (MRI) 1 day before the injection of Caelyx and 2 days after treatment start showed that the combined treatment reduced the vascular volume and the vascular transfer rate of the MRI tracer. The results show that chemoirradiation with Caelyx induces synergistic treatment effects. Improved intratumoral drug uptake and distribution are responsible to some extent for the enhanced antitumor effect.

BACKGROUND: A better understanding of the development of metastatic disease and the identification of molecular markers for cancer spread would be useful for the design of improved treatment strategies. This study was conducted to identify gene expressions associated with metastatic phenotypes of locally advanced cervical carcinomas and investigate whether gains or losses of these genes could play a role in regulation of the transcripts. Gene expressions and copy number changes were determined in primary tumors from 29 patients with and 19 without diagnosed lymph node metastases by use of cDNA and genomic microarray techniques, respectively. RESULTS: Thirty-one genes that differed in expression between the node positive and negative tumors were identified. Expressions of eight of these genes (MRPL11, CKS2, PDK2, MRPS23, MSN, TBX3, KLF3, LSM3) correlated with progression free survival in univariate analysis and were therefore more strongly associated with metastatic phenotypes than the others. Immunohistochemistry data of CKS2 and MSN showed similar relationships to survival. The prognostic genes clustered into two groups, suggesting two major metastatic phenotypes. One group was associated with rapid proliferation, oxidative phosphorylation, invasiveness, and tumor size (MRPS23, MRPL11, CKS2, LSM3, TBX3, MSN) and another with hypoxia tolerance, anaerobic metabolism, and high lactate content (PDK2, KLF3). Multivariate analysis identified tumor volume and PDK2 expression as independent prognostic variables. Gene copy number changes of the differentially expressed genes were not frequent, but correlated with the expression level for seven genes, including MRPS23, MSN, and LSM3. CONCLUSION: Gene expressions associated with known metastatic phenotypes of cervical cancers were identified. Our findings may indicate molecular mechanisms underlying development of these phenotypes and be useful as markers of cancer spread. Gains or losses of the genes may be involved in development of the metastatic phenotypes in some cases, but other mechanisms for transcriptional regulation are probably important in the majority of tumors.

PURPOSE: Photochemical internalization is under development for improving macromolecular therapy by inducing photochemical damage to endocytic vesicles. This damage leads to the release of therapeutic macromolecules entrapped in endocytic vesicles into the cytosol. The macromolecules may in this way be able to interact with therapeutic targets instead of being degraded by lysosomal hydrolases. Bleomycin is used in several standard cancer chemotherapy regimens. Its hydrophilic and relatively large chemical structure limits its ability to penetrate membrane structures, which causes the accumulation of bleomycin in endocytic vesicles. The purpose of this study was to evaluate the therapeutic potential of aluminum phthalocyanine disulfonate (AlPcS2a)-based photochemical delivery of bleomycin. EXPERIMENTAL DESIGN: Three tumors of different origin were grown s.c. in BALB/c (nu/nu) mice. The photosensitizer AlPcS2a and bleomycin were systemically administered and the tumor area was exposed to red light when the tumor volume had reached 100 mm3. The tumor volume was measured frequently after treatment and the time for the tumor volume to reach 800 to 1,000 mm3 was selected as the end point. RESULTS: The photochemical delivery of bleomycin induced a delayed tumor regrowth, and in two out of three tumor models, lead to 60% complete response, whereas no complete responses were seen after treatment with bleomycin alone. A statistical model to assess synergism was established. Combination of the photochemical treatment and bleomycin was found to induce a synergistic delay in tumor growth. CONCLUSION: AlPcS2a-based photochemical internalization of bleomycin induces a synergistic inhibition of tumor growth in three different tumor models. This treatment combination should be further considered for clinical utilization.

Metastatic prostate cancer has an unpredictable long-term prognosis. At present, there are few specific predictors to indicate the outcome for the individual patient. We have studied immunoreactivity for type-2 carbohydrate structures, known to be involved in various cell adhesion processes, in patients with metastatic prostate cancer. One group of patients (n = 26) did not progress within 3 years after orchiectomy, while another group of patients (n = 33) progressed within 1 year following castration and survived less than 2 years. Among the parameters studied, sialyl LewisX carbohydrate up-regulation was the only variable showing significant association with poor prognosis (P < 0.01). Sialyl LewisX discriminated between these two outcome groups with 71% predictability and 96% specificity. Our results indicate that up-regulation of sialyl LewisX is associated with hormonal-resistant, aggressive disease. This prognostic marker may, therefore, have an important role in selecting proper treatment for patients with metastatic prostate cancer.