Tumor Growth In Experimental Models Research Articles

Integrating electromagnetic cancer stress with immunotherapy: a therapeutic paradigm

An array of published cell-based and small animal studies have demonstrated a variety of exposures of cancer cells or experimental carcinomas to electromagnetic (EM) wave platforms that are non-ionizing and non-thermal. Overall effects appear to be inhibitory, inducing cancer cell stress or death as well as inhibition in tumor growth in experimental models. A variety of physical input variables, including discrete frequencies, amplitudes, and exposure times, have been tested, but drawing methodologic rationale and mechanistic conclusions across studies is challenging. Nevertheless, outputs such as tumor cytotoxicity, apoptosis, tumor membrane electroporation and leak, and reactive oxygen species generation are intriguing. Early EM platforms in humans employ pulsed electric fields applied either externally or using interventional tumor contact to induce tumor cell electroporation with stromal, vascular, and immunologic sparing. It is also possible that direct or external exposures to non-thermal EM waves or pulsed magnetic fields may generate electromotive forces to engage with unique tumor cell properties, including tumor glycocalyx to induce carcinoma membrane disruption and stress, providing novel avenues to augment tumor antigen release, cross-presentation by tumor-resident immune cells, and anti-tumor immunity. Integration with existing checkpoint inhibitor strategies to boost immunotherapeutic effects in carcinomas may also emerge as a broadly effective strategy, but little has been considered or tested in this area. Unlike the use of chemo/radiation and/or targeted therapies in cancer, EM platforms may allow for the survival of tumor-associated immunologic cells, including naïve and sensitized anti-tumor T cells. Moreover, EM-induced cancer cell stress and apoptosis may potentiate endogenous tumor antigen-specific anti-tumor immunity. Clinical studies examining a few of these combined EM-platform approaches are in their infancy, and a greater thrust in research (including basic, clinical, and translational work) in understanding how EM platforms may integrate with immunotherapy will be critical in driving advances in cancer outcomes under this promising combination.

In vivo induction of activin A-producing alveolar macrophages supports the progression of lung cell carcinoma

Alveolar macrophages (AMs) are crucial for maintaining normal lung function. They are abundant in lung cancer tissues, but their pathophysiological significance remains unknown. Here we show, using an orthotopic murine lung cancer model and human carcinoma samples, that AMs support cancer cell proliferation and thus contribute to unfavourable outcome. Inhibin beta A (INHBA) expression is upregulated in AMs under tumor-bearing conditions, leading to the secretion of activin A, a homodimer of INHBA. Accordingly, follistatin, an antagonist of activin A is able to inhibit lung cancer cell proliferation. Single-cell RNA sequence analysis identifies a characteristic subset of AMs specifically induced in the tumor environment that are abundant in INHBA, and distinct from INHBA-expressing AMs in normal lungs. Moreover, postnatal deletion of INHBA/activin A could limit tumor growth in experimental models. Collectively, our findings demonstrate the critical pathological role of activin A-producing AMs in tumorigenesis, and provides means to clearly distinguish them from their healthy counterparts.

645 Melanoma and the protective role of phosphorylated α-syn (pSer129) to prevent malignant degeneration

Background:The misfolding and prion-like propagation of the protein alpha-synuclein(α-Syn) is the leading molecular signature in Parkinson’s disease(PD). It has a protective role in the nucleus, where it is recruited to DNA double-strand break sites to promote DNA damage response and repair. The protein α-Syn is also highly expressed in melanoma. Elevated levels correlate with poorer survival to melanoma and α-Syn expression is required for tumor growth in experimental models. Phosphorylated α-Syn(pSer129) is associated with enhanced nuclear localization.

Efficacy of radiation treatment in combination with COX-2 inhibitor in patients with NSCLC

Background. COX-2 inhibitors facilitate disruption of the production of angiogenic factors, the use of which in combination with RT leads to a significant delay in tumor growth in experimental models of cancer.
 Purpose. Evaluation of the effectiveness of RT in combination with COX-2 inhibitor in patients with NSCLC (non-small-cell lung carcinoma).
 Materials and methods. The study involved 38 patients with NSCLC divided into 2 subgroups: Subgroup 1 was represented by 20 patients who received a RT course and celecoxib 100 mg/d, Subgroup 2 enrolled 18 patients who received only RT. The subgroups were comparable by sex, age, tumor location, general condition. Squamous cell carcinoma was detected in 19 (95.0%) patients of Subgroup 1 and in 9 (50%) patients of Subgroup 2. Stages I – II were diagnosed 4.4 times more frequently in Subgroup 2, stage III was 1.9 times more frequently detected in Subgroup 1 (p < 0.05).
 VEGF, COX-2 content was assessed before/after the RT course by means of a sandwich immunoassay (ELISA).
 Results. A positive effect (partial regression, stabilization) was observed equally in the subgroups: 80.0% and 77.8%. In Subgroup 1, partial regression was 5 times more frequent, the overall annual and recurrence-free survival increased by 15 and 29%, respectively.
 In patients of Subgroup 1, COX-2 was 2.4-fold decreased, in patients of Subgroup 2, COX-2 almost did not change. COX-2 blocking was accompanied by decreased VEGF: 1.9-fold in Subgroup 1, 1.4-fold in Subgroup 2. Changes in COX-2 and VEGF levels were consistent with the objective response after RT with celecoxib: in case of a positive effect, COX-2 level was significantly decreasing (2.3-1.9-fold), VEGF level was significantly decreasing (2.3–1.7-fold); progressive tumor growth was combined with a minor decrease in COX-2 and VEGF (1.5–1.4-fold).
 Conclusions. Radiation therapy in combination with COX-2 inhibitor enhances the effectiveness of treatment by increasing partial regressions and relapse-free survival. An objective response correlates with COX-2 and VEGF levels, which makes it possible to use them to assess RT effectiveness and decide on further treatment strategy.

A Somatostatin Receptor Subtype-3 (SST3) Peptide Agonist Shows Antitumor Effects in Experimental Models of Nonfunctioning Pituitary Tumors

Somatostatin analogues (SSA) are efficacious and safe treatments for a variety of neuroendocrine tumors, especially pituitary neuroendocrine tumors (PitNET). Their therapeutic effects are mainly mediated by somatostatin receptors SST2 and SST5. Most SSAs, such as octreotide/lanreotide/pasireotide, are either nonselective or activate mainly SST2. However, nonfunctioning pituitary tumors (NFPTs), the most common PitNET type, mainly express SST3 and finding peptides that activate this particular somatostatin receptor has been very challenging. Therefore, the main objective of this study was to identify SST3-agonists and characterize their effects on experimental NFPT models. Binding to SSTs and cAMP level determinations were used to screen a peptide library and identify SST3-agonists. Key functional parameters (cell viability/caspase activity/chromogranin-A secretion/mRNA expression/intracellular signaling pathways) were assessed on NFPT primary cell cultures in response to SST3-agonists. Tumor growth was assessed in a preclinical PitNET mouse model treated with a SST3-agonist. We successfully identified the first SST3-agonist peptides. SST3-agonists lowered cell viability and chromogranin-A secretion, increased apoptosis in vitro, and reduced tumor growth in a preclinical PitNET model. As expected, inhibition of cell viability in response to SST3-agonists defined two NFPT populations: responsive and unresponsive, wherein responsive NFPTs expressed more SST3 than unresponsive NFPTs and exhibited a profound reduction of MAPK, PI3K-AKT/mTOR, and JAK/STAT signaling pathways upon SST3-agonist treatments. Concurrently, SSTR3 silencing increased cell viability in a subset of NFPTs. This study demonstrates that SST3-agonists activate signaling mechanisms that reduce NFPT cell viability and inhibit pituitary tumor growth in experimental models that expresses SST3, suggesting that targeting this receptor could be an efficacious treatment for NFPTs.

The combination of bevacizumab/Avastin and erlotinib/Tarceva is relevant for the treatment of metastatic renal cell carcinoma: the role of a synonymous mutation of the EGFR receptor.

Metastatic clear cell renal cell carcinomas (mRCC) over-express the vascular endothelial growth factor (VEGF). Hence, the anti-VEGF antibody bevacizumab/Avastin (BVZ) combined with interferon alpha (IFN) was approved for the treatment of mRCC. However, approval was lost in July 2016 due to the absence of sustained efficacy. We previously showed that BVZ accelerates tumor growth in experimental models of mRCC in mice, results in part explained by down-regulation of the phospho tyrosine phosphatase receptor kappa (PTPRκ) in tumor cells. The epidermal growth factor receptor (EGFR) is a direct target of PTPRκ. Its down-regulation leads to constitutive activation of EGFR, an observation which prompted us to test the effect of the EGFR inhibitor erlotinib/Tarceva (ERLO) in addition to BVZ/IFN. The influence of the long non-coding RNA, EGFR-AS1, on ERLO efficacy was also addressed.Methods: The effect of BVZ/IFN/ERLO was tested on the growth of experimental tumors in nude mice. The presence of germline mutation in the EGFR was evaluated on cell lines and primary RCC cells. In vitro translation and transfections of expression vectors coding the wild-type or the EGFR mutated gene in HEK-293 cells were used to test the role of EGFR mutation of the ERLO efficacy. Correlation between EGFR/EGFR-AS1 expression and survival was analyzed with an online available data base (TCGA).Results: Tumor growth was strongly reduced by the triple combination BVZ/IFN/ERLO and linked to reduced levels of pro-angiogenic/pro-inflammatory cytokines of the ELR+CXCL family and to subsequent inhibition of vascularization, a decreased number of lymphatic vessels and polarization of macrophages towards the M1 phenotype. Cells isolated from surgical resection of human tumors presented a range of sensitivity to ERLO depending on the presence of a newly detected mutation in the EGFR and to the presence of EGFR-AS1.Conclusions: Our results point-out that the BVZ/IFN/ERLO combination deserves testing for the treatment of mRCC that have a specific mutation in the EGFR.

Inhibition of Fatty Acid Synthase Sensitizes Prostate Cancer Cells to Radiotherapy.

Many common human cancers, including colon, prostate and breast cancer, express high levels of fatty acid synthase compared to normal human tissues. This elevated expression is associated with protection against apoptosis, increased metastasis and poor prognosis. Inhibitors of fatty acid synthase, such as the cerulenin synthetic analog C75, decrease prostate cancer cell proliferation, increase apoptosis and decrease tumor growth in experimental models. Although radiotherapy is widely used in the treatment of prostate cancer patients, the risk of damage to neighboring normal organs limits the radiation dose that can be delivered. In this study, we examined the potential of fatty acid synthase inhibition to sensitize prostate cancer cells to radiotherapy. The efficacy of C75 alone or in combination with X irradiation was examined in monolayers and in multicellular tumor spheroids. Treatment with C75 alone decreased clonogenic survival, an effect that was abrogated by the antioxidant. C75 treatment also delayed spheroid growth in a concentration-dependent manner. The radiosensitizing effect of C75 was indicated by combination index values between 0.65 and 0.71 and the reduced surviving fraction of clonogens, in response to 2 Gy X irradiation, from 0.51 to 0.30 and 0.11 in the presence of 25 and 35 μM C75, respectively. This increased sensitivity to radiation was reduced by the presence of the antioxidant. The C75 treatment also enhanced the spheroid growth delay induced by X irradiation in a supra-additive manner. The level of radiation-induced apoptosis in prostate cancer cells was increased further by C75, which induced cell cycle arrest in the G2/M phase, but only at a concentration greater than that required for radiosensitization. Radiation-induced G2/M blockade was not affected by C75 treatment. These results suggest the potential use of fatty acid synthase inhibition to enhance the efficacy of radiotherapy of prostate carcinoma and that C75-dependent cell cycle arrest is not responsible for its radiosensitizing effect.

P04.12 * URINARY GELATINASE ACTIVITIES (MATRIX METALLOPROTEINASES 2 AND 9) IN HUMAN MENINGIOMA AND GLIOBLASTOMA

Currently, there are no generally accepted screening protocols for the discovery of asymptomatic brain tumors, particularly primary brain tumors. Therefore it would be desirable to develop novel, noninvasive biomarkers for the detection of brain tumors. Remodeling of the extracellular matrix and dysregulation of angiogenesis are process essential to the development and maintenance of many tumors. Matrix metalloproteinases (MMPs), a multigene family of degradative enzymes, have been implicated in the establishment and maintenance of the vasculature required for tumor progression and metastasis as well as in the initial angiogenic phase of tumor growth in experimental models and human tumors. In the central nervous system MMPs have been associated with brain tumor development. Studies of primary brain tumors reveal that MMP-2 and MMP-9, and several other MMPs are overexpressed in both experimental models and tissue samples from human patients. Furthemore, urinary levels of MMP-2 (gelatinase A) and MMP-9 (gelatinase B) and their complex are elevated in patients with a variety of cancers, both organ confined and metastatic, both within and outside the urogenital tract. Given that (1) MMPs are present in brain tumors and (2) that urinary MMPs have shown utility as noninvasive biomarkers for non central nervous system cancer, we initiated this study to determine whether urinary MMPs might have potential as noninvasive biomarkers to detect the presence of brain tumors. In the present preliminary study, we determined the gelatinolytic activities in urine from patients with brain tumor (15 meningioma and 10 glioblastoma) and from and 20 healthy volunteers with no concomitant illnesses using gelatin zymography. The diagnosis of tumor was made using usual clinical and imaging criteria and confirmed by histopathological findings. First morning urine were collected from patients before surgical intervention. To investigate the gelatinolytic activity present in the concentrate urine, substrate gel zymography was performed. This method simultaneously identifies the entire panel of enzymes that are capable of degrading the specific substrate, and the activity is detected by a clear zone in the gel where the substrate (gelatin) has been digest by the enzyme. Gelatin zymography identified that MMPs were present in the urine of many patients with meningioma and glioblastoma, whereas only traces of MMP could be detected in the urine of healthy subjects with no evidence of disease. Five dominant proteinases were detected migrating at approximately 240, 220, 130 and 92 kDa (MMP-9) and 72 kDa (MMP-2). These preliminary results indicate that MMPs correlate with presence of disease. Other experiments are ongoing to verify whether these biomarkers decrease with treatment and can be tracked from source tissue to urine.

Immunotoxin targeting EpCAM effectively inhibits peritoneal tumor growth in experimental models of mucinous peritoneal surface malignancies

Cytoreductive surgery and intraperitoneal (i.p.) chemotherapy constitute a curative treatment option in mucinous peritoneal surface malignancies of intestinal origin, but treatment outcome is highly variable and the search for novel therapies is warranted. Immunotoxins are attractive candidates for targeted therapy in the peritoneal cavity because of direct cytotoxicity, distinct mechanisms of action and tumor cell selectivity. The MOC31PE immunotoxin targets the tumor-associated adhesion protein EpCAM (Epithelial Cell Adhesion Molecule), and has been administered safely in early clinical trials. In our work, the efficacy of i.p. administration of MOC31PE alone and together with mitomycin C (MMC) was investigated in unique animal models of human mucinous peritoneal surface malignancies. In initial model validation experiments, clear differences in efficacy were demonstrated between MMC and oxaliplatin, favoring MMC in five investigated tumor models. Subsequently, MOC31PE and MMC were given as single i.p. injections alone and in combination. In the PMCA-2 model, moderate growth inhibition was obtained with both drugs, while the combination resulted in at least additive effects; whereas the PMP-2 model was highly sensitive to both drugs separately and in combination and intermediate sensitivity was found for the PMCA-3 model. Furthermore, results from ex vivo experiments on freshly obtained mucinous tumor tissue from animals and patients suggested that classic mechanisms of immunotoxin activity were involved, i.e., inhibition of protein synthesis and induction of apoptosis. The present results suggest that adding MOC31PE to MMC-based i.p. chemotherapy should be further explored for EpCAM-expressing peritoneal surface malignancies, and a phase I trial is in preparation.

The emerging role of T cell cytokines in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is among the most frequent types of cancer and associated with significant mortality. Recent studies suggest that tumor infiltrating T lymphocytes and their immunoregulatory cytokines play a fundamental role in controlling tumor growth and metastasis. Whereas T helper 1 cells and their master transcription factor T-bet have been identified as important regulators of IFN-gamma driven anti-tumoral immune response, IL-17 producing T helper 17 cells expressing RORA/C transcription factors have been found to augment tumor growth and cell proliferation in NSCLC. Furthermore, regulatory T cells were shown to impair immune responses against lung cancer. As modulation of T cell cytokines such as IL-17A has been recently shown to suppress tumor growth in experimental models, anti-cytokine agents emerge as a promising new approach for treatment of lung cancer.

Abstract 3834: JKA97, a novel anti-cancer candidate, induces G1 arrest via up-regulation of p21 in a p53-independent manner

Abstract Breast cancer is one of the most commonly diagnosed cancers and the leading causes of cancer death in women worldwide. Natural product-oriented synthetic derivatives have played an important role in cancer drug discovery. JKA97, a benzylidene analog of harmine, is a novel anti-cancer candidate. The initial studies have shown its inhibitory effects on tumor growth in experimental models. However, the underlying molecular mechanisms are not fully elucidated. In this study, we determined the anti-cancer effects of JKA97 on human breast cancer in vitro and in vivo. Our data showed that, in a dose-dependent manner, JKA97 efficiently inhibited the growth and proliferation of human breast cancer cells with different p53 status, including MCF7 (p53 wild-type), MCF7 (p53 knockdown) and MDA-MB-468 (p53 mutant) cells. We also found that JKA97 induced apoptosis in human breast cancer cells independent of p53 and that JKA97 treatment resulted in G1 phase arrest in all the three breast cancer cell lines. In vivo, JKA97 significantly suppressed the growth of both breast cancer MCF7 and MDA-MB-468 xenograft tumors. Mechanistically, JKA97 modulated the levels of various cell-cycle regulators involved in G1 to S phase progression, such as p21, p27, cyclinE, and cyclinD1. Our results indicated that p21 and p27were up-regulated while cyclinE and cyclinD1 were down-regulated by JKA97 treatment. Using quantitative PCR and luciferase reporter assays, we demonstrated that the major mechanism for G1 phase arrest by JKA97 was induction of p21 at the transcriptional level, independent of p53. We further confirmed the role of p21 in JKA97-induced G1 phase arrest by using HCT116 cells with or without p21 expression. Taken together, these findings suggest that JKA97 inhibits human breast cancer by inducing cell cycle arrest through up-regulation of p21, regardless of p53 status. Considering that more than 50% human cancers have no or mutant p53 expression, our results provide a basis for further development of this compound as potential drug for breast cancer therapy. (This work was supported in part by NIH/NCI grants R01 CA112029 and R01 CA121211, R15 CA100102 and a grant (BCTR070731) from Susan G Komen for the Cure.) Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3834. doi:1538-7445.AM2012-3834

Expression of interleukin-17 in experimental models of murine mammary carcinoma

Objective To explore the impact of interleukin (IL) -17 expression on tumor growth in experimental models of murine mammary carcinoma and potential mechanisms. Methods Two murine cell lines, MA782/5S28102 and 4T1 were used to establish experimental models of murine mammary carcinoma. The IL-17 expression in tumor tissues derived from MA782-bearing mice or 4T1-bearing mice was detected in early and late stages of the tumor by Western blotting. The tumor cells and tumor-infiltrated-lymphocytes were separated from tumor tissues and cultured for 5 days with stimulation of PMA, anti-CD3 antibody and anti-CD28 antibody. The supernatants of culture media of stimulated tumor cells or tumor-infiltrated-lymphocytes were harvested and tested for IL-17 concentration by enzyme linked immunosorbent assay (ELISA). To evaluate the effect of IL-17 on the proliferation of tumor cells, 4T1 cells were culture in media with or without IL-17 and the cell number was counted on the day 5. For ire vivo assay, 4T1-bearing mice were injected with IL-17 or culture media via tail vein, and the tumor volume was measured. To assay the angiogenesis, the tumor tissues from 4T1-bearing mice with or without injection of IL-17 were stained with anti-CD31 antibody by immunohistochemistry. Results The IL-17 expression was significantly higher in late stage than in early stage of tumor in two experimental models. The tumor expression of IL-17 was secreted by tumor infiltrated lymphocytes (P ＜0.01). IL-17 could not increase the generation of tumor cells in vitro (1. 11 ±0. 11, 1. 28 ±0. 21 ,P ＞0. 05). But IL-17, injected into 4T1 -bearing mice, markedly enhanced in vivo tumor growth and significantly increased tumor vascularity (35. 79 ±9. 49, 13. 52 ±3. 55,P ＜0.01). Conclusion IL-17 in tumor tissue probably promotes tumor growth through enhancing angiogenesis. Key words: Mammary carcinoma; IL-17; Angiogenesis

53 Down regulation of beta-catenin by a locked nucleic acid oligonucleotide antagonist inhibits tumor growth in experimental models of human cancer

53 Down regulation of beta-catenin by a locked nucleic acid oligonucleotide antagonist inhibits tumor growth in experimental models of human cancer

Inflammation and colorectal cancer

Patients with long-standing inflammatory bowel disease (IBD) have an increased risk of developing colorectal cancer (CRC). However, the underlying mechanisms are not entirely clear. A genetic basis for the increased risk of CRC in IBD patients is only a partial explanation. It is possible that high levels of inflammatory mediators that are produced in this setting may contribute to the development and progression of CRC. Growing evidence supports a role for various cytokines, released by epithelial and immune cells, in the pathogenesis of IBD-associated neoplasia. Two key genes in the inflammatory process, cyclooxygenase-2 (COX-2) and nuclear factor kappaB (NF-kappaB), provide a mechanistic link between inflammation and cancer while other factors such as, TNF-alpha and IL-6-induced signaling have been recently shown to promote tumor growth in experimental models of colitis-associated cancer. This article reviews the pathogenesis of IBD-related CRC and summarizes the molecular mechanisms underlying the development of intestinal neoplasia in the setting of chronic inflammation.

Altered circadian rhythm in rest and activity (CircAct): Independent prognostic value for survival in patients (pts) with metastatic colorectal cancer (MCC)

14573 Background: Altered CircAct accelerated tumor growth in experimental models (JNCI 2002, 2005; Cancer Res 2004). CircAct was found to be related to survival in two studies (St) in MCC pts (St 1, Clin Cancer Res 2000; St 2, ASCO 2005 #3553). The current study attempted to provide an independent prognostic stratification criteria for survival according to baseline CircAct as a first step toward the development of a comprehensive prognostic model based on circadian physiology. Methods: CircAct was continuously and non- invasively assessed over 72h with a wrist accelerometer (Ambulatory Monitoring, USA), before chemotherapy in two independent datasets of 169 MCC pts (60% pretreated) at Paul Brousse Hospital (St 1) and 130 chemo-naïve MCC pts registered in the international EORTC 05963 trial (St 2). Activity distribution during rest and wakefulness was objectively quantified by I<O (50=no rhythm; 100=marked rhythm). Kaplan-Meier survival curves with logrank tests and Cox regression models were used for analyses. Results: In both St, pts with I<O = 92 (21% in St 1 and 22% in St 2) displayed a significantly poorer survival as compared to those pts with I<O > 92 (Table). The hazard ratios (HR) were 0.37 [95%CI: 0.25 to 0.55] (p<0.0001) in St 1 and 0.56 [0.36 to 0.87] (p=0.01) in St 2. The prognostic value of altered CircAct persisted after adjusting for PS (HR=0.46 [0.30 to 0.69], p=0.0002 in St 1; HR=0.61 [0.38 to 0.97], p=0.04 in St 2). Conclusions: The independent stratification of MCC pts for survival according to baseline altered CircAct occurred using a threshold value of 92 for I<O in both separate datasets. Subsequent studies will involve additional biomarkers of circadian physiology (cortisol, melatonin, clock genes) in order to further improve this prognostic stratification as a step toward tailored treatment of MCC pts. [Table: see text] No significant financial relationships to disclose.

Perioperative Immunomodulation With Flt3 Kinase Ligand or a Whole Tumor Cell Vaccine Is Associated With a Reduction in Lung Metastasis Formation After Laparotomy in Mice

Laparotomy has been associated with temporary postoperative immunosuppression and accelerated tumor growth in experimental models. In a previous murine study, a whole cell vaccine plus the adjuvant monophosphoryl-lipid A was shown to be effective in decreasing the number of lung metastases that develop after laparotomy. This study was conducted to assess the impact of the adjuvant fetal liver tyrosine kinase 3 (Flt3) ligand on perioperative tumor growth when used alone or with a tumor cell vaccine. An intravenous tumor cell injection lung metastases model was used. Sixty female A/J mice were divided into six equal groups designated (1) anesthesia control (AC), (2) AC with Flt3 ligand (ACFlt3), (3) sham laparotomy (OP), (4) OP with Flt3 ligand (OPFlt3), (5) OP with vaccine (OPVac), and (6) OP with Flt3 ligand and vaccine (OPFlt3Vac). Groups 2, 4, and 6 received daily intraperitoneal injections of Flt3 ligand (10 microg/dose with carrier) for 5 days before and 5 days after surgery. Groups 1 and 3 received similar injections of saline on the same schedule. Groups 5 and 6 were vaccinated with irradiated whole Ta3Ha tumor cells intraperitoneally three times before and twice after surgery. Immediately after surgery, all mice were injected with 10(5) Ta3Ha tumor cells via a tail vein. After 14 days, the mice were sacrificed and their lungs and tracheas were excised en bloc. Specimens were stained and counterstained with India ink and Fekete solution, and surface metastases were counted by a blinded observer. Differences between study groups were determined by analysis of variance. The peritumoral inflammatory cell infiltrate of some Flt3 and control specimens was also assessed. Regarding laparotomy, Flt3 ligand (mean, 1.22 metastases), whole cell vaccine (1.12 metastases), and the combination of these two agents (0.1 metastases) were each effective in significantly decreasing the number of surface lung metastases compared with surgery alone (9.88 metastases, P < .05 for all comparisons). There were no differences between the various treatment groups in regards to number of metastases. Only the combination of Flt3 and the vaccine significantly lowered the incidence of tumors (number of mice with > or =1 tumors). Histologic analysis revealed that the Flt3-treated mice demonstrated increased numbers of antigen-presenting cells surrounding the tumors compared with controls. Perioperative treatment with either Flt3 ligand or a whole cell tumor vaccine significantly reduced the number of lung metastases after laparotomy. The combination of the Flt3 ligand and the vaccine also decreased the incidence of metastases and was the most effective treatment. Further studies regarding perioperative immune modulation in the setting of cancer appear warranted.

Immunomodulatory and antimetastatic action of propolis and related polyphenolic compounds

The effect of polyphenolic compounds isolated from propolis and propolis itself was investigated on the growth and metastatic potential of a transplantable mammary carcinoma (MCa) of CBA mouse. Metastases in the lung were generated by intravenous injection of tumor cells (2 × 10 5). A water-soluble derivative of proplis (WSDP), caffeic acid (CA), caffeic acid phenethyl ester (CAPE) and quercetin (QU) were given to mice per os before tumor cells inoculation. Tested compounds significantly decreased the number of tumor nodules in the lung. According to the results obtained the antitumor activity of tested compounds can be related to the immunomodulatory properties of the compounds, their cytotoxicity to tumor cells, and their capacity to induce apoptosis and necrosis. The experimental data support that WSDP, CA, CAPE and QU could be potentially useful in the control of tumor growth in experimental models.

Quantitation of Tumor Seeding From Fine Needle Aspiration of Ocular Melanomas

Twenty-two fine needle (30 gauge) aspirations were performed in eyes enucleated for the clinical diagnosis of melanoma. Cytologic preparations were evaluated for adequacy of material, and needle tracts were evaluated for tumor implantation. A scleral marking method was used to identify all needle tracts. The number of tumor cells in tracts of direct transscleral aspirates was compared to those in tracts of indirect aspirates that traversed the anterior chamber or vitreous. Cellular material obtained with 30-gauge needles was sufficient for the diagnosis of malignant melanoma in all but one case. While 14 of 21 (67%) of all fine needle aspiration tracts and eight of 15 (53%) of indirect tracts contained tumor cells, the number of tumor cells was less than that associated with tumor growth in experimental models. Indirect aspirate tracts contained significantly fewer cells than tracts of direct aspirates (P less than .001).