Mean Tumor Mass Research Articles

Abstract 3250: LNA gapmer to gastrin inhibits growth and metastases of human pancreatic cancer in mice

Abstract Background: Pancreatic cancer has a poor prognosis and novel strategies are needed to improve the survival. Gastrin stimulates growth of pancreatic cancer by an autocrine mechanism and RNAi techniques that decrease gastrin expression have been shown to inhibit growth of this malignancy in vitro. Locked nucleic acid (LNA) Gapmers are antisense oligonucleotides (ASO) that have long half-life and stability in vivo, hence represent a potential method to deliver RNAi for cancer therapeutics. We developed an LNA Gapmer that selectively downregulates gastrin expression in pancreatic cancer cells in culture. The goal of this project was to test this anti-gastrin Gapmer in vivo as a novel therapy for pancreatic cancer. Methods: The anti-gastrin LNA Gapmer was modified using thiol-click chemistry to conjugate a peptide to the 5’ end and render the Gapmer target-specific with the ability to bind selectively to the cholecystokinin-B receptor that is over-expressed in pancreatic cancer. Forty athymic nude mice with established AsPC-1 human pancreatic orthotopic tumors were divided into four groups of equal tumor size. Mice (N=10 per group) were treated with PBS (controls), an untargeted LNA-Gapmer, the CCK-BR targeted Gapmer (60nM), and the CCK-BR targeted Gapmer (120nM) intraperitoneally twice a week for 4 weeks. Growth was monitored by luciferase IVIS imaging. At necropsy, tumors were excised, and metastases counted. Results: Mean tumor mass was 43% smaller in mice treated with the targeted Gapmer-120nM (P=0.0007). Untargeted and targeted Gapmer 60nM slightly decreased tumor mass but this difference was not significant. Compared to PBS control-treated mice, metastases were significantly less in mice treated with the untargeted Gapmer by -39% (p=0.01); in the targeted Gapmer-60nM by -44% (p=0.003), and with the targeted Gapmer-120nM by -72% (p<0.0001). Gastrin mRNA analysis of the tumors by qRT-PCR confirmed downregulation of gastrin. Conclusion: Novel LNA Gapmers that downregulate gastrin mRNA expression decrease growth and metastases of pancreatic cancer in a dose-related fashion. Citation Format: Godhanjali Chekuri, Wenqiang Chen, Narayan Shivapurkar, Hong Cao, Ruvanthi N. Kularatne, Stephan Stern, Jill P. Smith. LNA gapmer to gastrin inhibits growth and metastases of human pancreatic cancer in mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3250.

Is higher body mass index associated with secondary osteoarthritis in patients treated with bone cement for benign aggressive bone tumors? Long-term evaluation of 43 patients

BackgroundThis study was designed to investigate the secondary osteoarthritis rate in patients with benign aggressive bone tumors treated with curettage and cementing at long-term follow up. MethodsPatients diagnosed with benign aggressive bone tumor (giant cell or aneurysmal bone cyst), treated with extended curettage and cementation with polymethylmethacrylate, who had a minimum of 60 months of follow up after surgery were included in this study. After definitive diagnoses were confirmed by a histopathologist, we decided to perform standard surgical management. Osteoarthritis was staged radiologically using the Kellgren–Lawrence scoring system, and the contralateral knees of the patients were used as the control group. Based on the Kellgren–Lawrence classification system, stages 3 and 4 were accepted as the existence of osteoarthritis. Body mass index, the distance to the subchondral joint line, tumor mass volume, the location of the tumor (i.e., femur, tibia, medial condyle, or lateral condyle), age, and sex were also investigated, all of which are factors that can affect the occurrence of osteoarthritis. ResultsForty-three patients, 24 male (56%) and 19 female (44%), were included in the study. The mean age of the patients was 29.5 ± 10 years, and mean follow up duration was 128.7 months. Tumor localization was the distal femur in 20 patients (46.5%) and the proximal tibia in 23 patients (53.5%). The mean tumor mass volume was 77.84 cm3 and the distance to the knee joint subchondral line was 3.2 ± 2 mm. According to this scoring system, 14 patients were at stage 0, 10 patients were at stage 1, 10 patients were at stage 2, four patients were at stage 3, and five patients were at stage 4. When we compared osteoarthritis development, the affected knee had a significantly higher rate of osteoarthritis development than the contralateral knee. A univariate analysis demonstrated that age (P = 0.002) and body mass index (P = 0.045) were associated with secondary osteoarthritis. Moreover, multivariate analysis demonstrated that none of the variables were independently associated with secondary osteoarthritis. ConclusionPatients with contralateral osteoarthritis had bilateral knee osteoarthritis, indicating that primary osteoarthritis progressed in both knees. Seven of the 43 patients (16.2%) showed secondary osteoarthritis. Although age and body mass index were associated with secondary osteoarthritis in univariate analysis, none of the variables were independently associated with secondary osteoarthritis in the multivariate analysis.

Biological evaluation of the novel 3,3′-((4-nitrophenyl)methylene)bis(4-hydroxy-2H-chromen-2-one) derivative as potential anticancer agents via the selective induction of reactive oxygen species-mediated apoptosis

Selective initiation of programmed cell death in cancer cells than normal cells is reflected as an attractive chemotherapeutic strategy. In the current study, a series of synthetic bis-coumarin derivatives were synthesized possessing reactive oxygen species (ROS) modulating functional groups and examined in four cancerous and two normal cell lines for their cytotoxic ability using MTT assay. Among these compounds, 3 l emerged as the most promising derivative in persuading apoptosis in human renal carcinoma cells (SKRC-45) among diverse cancer cell lines. 3 l causes significantly less cytotoxicity to normal kidney cells compared to cisplatin. This compound was able to induce apoptosis and cell-cycle arrest by modulating the p53 mediated apoptotic pathways via the generation of ROS, decreasing mitochondrial membrane potential, and causing DNA fragmentation. Unlike cisplatin, the 3 l derivative was found to inhibit the nuclear localisation of NF-κB in SKRC-45 cells. It was also found to reduce the proliferation, survival and migration ability of SKRC-45 cells by downregulating COX-2/ PTGES2 cascade and MMP-2. In an in vivo tumor model, 3 l showed an anticancer effect by reducing the mean tumor mass, volume and inducing caspase-3 activation, without affecting kidney function. Further studies are needed to establish 3 l as a promising anti-cancer drug candidate.

Tumor dosimetry of [177Lu]Lu-PSMA-617 for the treatment of metastatic castration-resistant prostate cancer: Results from the VISION trial sub-study.

5046 Background: In VISION, lutetium (177Lu) vipivotide tetraxetan ([177Lu]Lu-PSMA-617; 177Lu-PSMA-617) plus protocol-permitted standard of care (SoC) significantly improved overall survival and radiographic progression-free survival compared with SoC alone, in patients with prostate-specific membrane antigen (PSMA)-positive metastatic castration-resistant prostate cancer. In a VISION dosimetry sub-study, 177Lu-PSMA-617 had a good safety profile with low radiotoxicity in at-risk organs. Here, we estimated the dosimetry of tumors after administration of 177Lu-PSMA-617. Methods: The VISION sub-study was performed in a separate cohort of 29 non-randomized participants at four sites in Germany. Eligible patients received 177Lu-PSMA-617 (7.4 GBq every 6 weeks, ≤ 6 cycles) plus SoC. Patients underwent single-photon emission computed tomography/computed tomography (SPECT/CT) scans at approximately 2, 24, 48 and 168 hours after the first administration of 177Lu-PSMA-617 (Cycle 1). Up to five tumors in each patient were selected according to tumor size and relative activity uptake. Tumor delineation, volume and morphology were determined using positron emission tomography (PET)/CT images. Kinetic (time-activity) data was determined using SPECT images and the application of phantom derived recovery coefficients. Tumor dosimetry was estimated using the standard Medical Internal Radiation Dose/Radiation Dose Assessment Resource (MIRD/RADAR) method for internal dosimetry. S-values were determined using CT-derived tumor volumes and tissue type as input to the Internal Dose Assessed by Computer (IDAC-Dose) 2.1 program. Tumor dosimetry estimates were reported as absorbed dose per unit activity (Gy/GBq) and cumulative estimated absorbed dose (Gy) over all 6 cycles (44.4 GBq cumulative activity). Results: In total, 104 tumors were analyzed after administration of 177Lu-PSMA-617 in Cycle 1. Tumor sites included bone (n = 84), lymphatic tissue (n = 18), lung tissue (n = 1) and soft tissue (n = 1). Mean tumor mass by site was 14.6 (standard deviation [SD], 29.8; range, 0.49–224) g for bone and 12.5 (15.9; 0.68–60.7) g for lymphatic tissue. The mean radiation-absorbed dose for all tumors was 6.5 (SD, 8.4; range, 0.13–55) Gy/GBq, and the median absorbed dose was 4.4 Gy/GBq. The mean radiation-absorbed dose by tumor site was 5.4 (SD, 6.0; range, 0.13–45) Gy/GBq for bone and 9.7 (12; 0.99–55) Gy/GBq for lymphatic tissue. The 6-cycle cumulative estimated absorbed dose for all tumors was 287 (SD, 373; range, 5.7–2432) Gy. The 6-cycle cumulative estimated absorbed dose by tumor site was 240 (SD, 268; range, 5.7–2010) Gy for bone and 429 (549; 44–2432) Gy for lymphatic tissue. Conclusions: Tumor dosimetry estimates after administration of 177Lu-PSMA-617 in the VISION sub-study patient population were consistent with previously published estimates. Clinical trial information: NCT03511664 .

Abstract 2520: Blocking muscle wasting via deletion of the muscle specific E3 ligase, MuRF1, impedes pancreatic tumor growth

Abstract Pancreatic cancer-induced muscle atrophy is a debilitating condition that contributes to a deterioration in physical function and reduced quality of life, often complicates or precludes cancer treatment, and strongly predicts early mortality from cancer. A pharmacological therapy for this atrophy does not exist, in part because of an incomplete understanding of the molecular mechanisms which are causative in the condition. We recently identified that Trim63/MuRF1 is elevated in skeletal myonuclei from cachectic mice and people with pancreatic ductal adenocarcinoma (PDAC) compared to non-cancer controls. MuRF1 is an E3 ubiquitin ligase, specific to striated muscle that targets proteins for degradation. Based on this finding, we investigated the requirement of MuRF1 for PDAC-induced muscle atrophy. Murine KPC cells (or saline) were injected orthotopically into the pancreas of WT and MuRF1 KO mice, and tissues harvested at several time points throughout tumor progression. WT KPC mice showed loss of tumor-free body mass and muscle mass by day 12, and reached experimental endpoint on day 16, defined by significant body wasting in combination with a body condition score ≤2. At endpoint, WT KPC mice showed significant muscle wasting (-8-17%), muscle weakness (-32-46%), fat wasting (-71%) and splenomegaly (+100%) and had a mean tumor mass of 1.9 ± 0.5 g. At this same timepoint (day 16), MuRF1 KO KPC mice were completely protected from body, muscle and fat wasting, with KPC tumors in MuRF1 KO mice 84% smaller than in WT mice. We therefore tracked an additional cohort of MuRF1 KO KPC mice until their tumors reached a comparable size to that of WT mice at their endpoint which, on average, was reached on day 32. Despite having comparable tumor mass at this time point, MuRF1 KO mice remained protected from body, muscle and fat wasting, and were spared from muscle weakness. Using ubiquitin proteomics in muscle, we found that MuRF1 was responsible for the ubiquitination of multiple cytoskeletal and contractile proteins—whose proteolytic degradation into amino acids may contribute to myofiber atrophy and help fuel tumor growth. To explore the impact of MuRF1 deletion on tumor metabolism we conducted global metabolomic profiling of KPC tumors from WT mice on day 16, and from MuRF1 KO mice on day 16 and at matched tumor size. Overall, these analyses revealed an accumulation of metabolites in tumors from MuRF1 KO mice, including glucose, amino acids and amino acid derivatives, suggesting that pancreatic tumors in mice spared from muscle wasting may be less metabolically active. In summary, these combined findings demonstrate that MuRF1 is required for KPC-induced skeletal muscle catabolism, whose deletion impinges on normal tumor metabolism and delays tumor growth. Citation Format: Daria Neyroud, Orlando Laitano, Christopher Lopez, David W. Hammers, H Lee Sweeney, Glenn A. Walter, Sarah M. Judge, Andrew R. Judge. Blocking muscle wasting via deletion of the muscle specific E3 ligase, MuRF1, impedes pancreatic tumor growth [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2520.

The Association Between Imaging Features of TSCT and the Expression of PD-L1 in Patients With Surgical Resection of Lung Adenocarcinoma

ObjectivesProgrammed death-ligand 1 (PD-L1) expression might serve as a predictive biomarker for immune checkpoint inhibitors in lung cancer. However, the relationship between PD-L1 expression and imaging features of lung cancer has not been fully understood. Patients and MethodsA total of 350 patients with pathologically confirmed adenocarcinoma who received surgical treatment and had preoperative thin section computed tomography (CT) examination were included. Quantitative CT features including the mean CT value and tumor mass were measured on multiplanar reconstructed images. PD–L1-positive tumor was defined as the tumor proportion score > 5%. ResultsSeventy-four of 350 (21.1%) specimens were detected as PD–L1-positive tumors. PD-L1 expression was adversely associated with epidermal growth factor receptor mutation status (P < .001) and was significantly associated with invasive adenocarcinomas rather than preinvasive lesions and minimally invasive adenocarcinomas (P < .001). Multivariate analysis identified absence of surrounding ground glass opacity (P = .022), shape (P = .008), pleural indentation (P = .007), tumor mean CT value (P = .004), and the ratio of consolidation mass to tumor mass (P = .003) as being significantly associated with the expression of PD-L1. To improve the diagnostic accuracy, a joint model that combined 5 imaging traits was conducted. The area under the curve of the joint model was 0.783, with a sensitivity of 81.1% and specificity of 64.1%, respectively. ConclusionPD-L1 expression was associated with pathologic invasiveness of adenocarcinomas and CT features, which suggested the possibility of predicting PD-L1 expression status via imaging features.

Radiofrequency ablation with systemic chemotherapy in the treatment of colorectal cancer liver metastasis: a 10-year single-center study.

ObjectiveTo retrospectively evaluate the long-term efficacy and safety of radiofrequency ablation (RFA) with systemic chemotherapy (CT) in treatment of solitary liver metastasis after surgery for colorectal cancer (CRC).MethodsThis single-center study was conducted at the Hunan Provincial Cancer Hospital from June 2006 to December 2015 with median follow-up time of 26 months. Percutaneous ultrasound-guided RFA was carried out on eligible patients with solitary liver metastasis after surgery for CRC. After a week, ablation status was confirmed by MRI. Post MRI, all patients received systemic CT with or without molecular-targeted therapy. Survival rate was evaluated and survival curve was constructed with Kaplan–Meier analysis. Log-rank test and Cox regression model were used for univariate and multivariate analysis, respectively, to determine the independent prognostic factors for survival rate.ResultsA total of 109 eligible patients (mean age, 53.84±11.71; mean tumor mass diameter, 3.4+2.01 cm) were enrolled in this 10-year study. After RFA, 95 patients achieved complete ablation, and 14 patients achieved partial ablation, with median ablation time of 26 minutes (range: 12–120 minutes). The median survival time required for achieving complete and partial ablation was 56.0 and 19.0 months, respectively (P<.01). After RFA and adjuvant systemic CT, the 1-, 3-, and 5-year survival rates were 92.3%, 50.7%, and 41.6%, respectively, with the median (mean) survival time of 39.0 (56.5) months. Age was the only significant independent prognostic factor with better survival rate observed in patients aged ≥50 years than those aged <50 years (P<0.05). The incidence of complications was minimal (1.8%) with only two cases: one biliary fistula and one liver hemorrhage.ConclusionRFA combination with systemic CT was safe; it showed long-term efficacy in patients with solitary liver metastasis after surgery for CRC and can be a preferred treatment.

Inhibitory effects and mechanism of 5-fluorouracil combined with celecoxib on human gastric cancer xenografts in nude mice.

5-Fluorouracil (5-Fu) is one of the most commonly used drugs to treat gastric cancer; however, drug-resistance in cancer cells reduces the efficacy of 5-Fu. Celecoxib may be able to reduce resistance to 5-Fu chemotherapy. The aim of the present study was to investigate the inhibitory effects of a combination of 5-Fu and celecoxib on implanted gastric cancer xenografts in nude mice and to elucidate the underlying mechanism. A tumor-bearing nude mice model was established. The mice were divided into blank control, 5-Fu, celecoxib and combination groups. The weight change and the tumor inhibition rate in each group were calculated. Immunocytochemistry, reverse transcription-polymerase chain reaction and western blotting methods were used to observe hypoxia-inducible factor-2α (HIF-2α), ATP-binding cassette transporter G2 (ABCG2) and octamer-binding transcription factor 4 (Oct-4) expression in the SGC7901 cells. Inhibition of the growth of the implanted gastric cancer was observed in the 5-Fu, celecoxib and combination groups. In the celecoxib and combination treatment groups, the mean tumor mass was significantly less than that in the control group (P<0.05), and the mean tumor mass in the combination treatment group was significantly less than that in the 5-Fu group (P<0.05). The tumor inhibition rates in the 5-Fu, celecoxib and combination groups were 26.36, 59.70 and 88.37%, respectively. The combination group exhibited the highest inhibition rate; the inhibition rates of the combination and celecoxib groups were significantly higher compared with the 5-Fu group (P<0.05). The expression levels of HIF-2, ABCG2 and Oct-4 mRNA and protein were high in the blank control group, and were further increased in the 5-Fu group. However, in the celecoxib and combination groups, the expression levels were lower compared with those in the control group. Significant differences were identified among the 5-Fu, celecoxib and combination groups (P<0.01). Celecoxib has antitumor effects in vivo. The mechanism may be associated with the reduced expression of cancer stem cell markers HIF-2α, Oct-4 and ABCG2. 5-Fu and celecoxib have a synergistic antitumor effect. The mechanism associated with the amelioration of resistance to chemotherapy in gastric cancer and the enhancement of the effect of chemotherapy may be via the reduction of the expression of HIF-2α, ABCG2, Oct-4 and other cancer stem cell markers in the tumor tissues.

Abstract 1855: Maternal consumption of long chain omega 3 fatty acids decreases risk for mammary gland cancer in the female C(3)1 TAg mouse

Abstract Omega 3 fatty acids have been shown to reduce incidence and slow growth of mammary gland cancer in rodent models. Omega 3 fatty acids in the maternal diet are important for normal fetal brain, eye and nervous system development. Since exposure to dietary components during the critical developmental times of gestation and lactation may alter risk for mammary gland cancer in females, we tested whether exposure to increased levels of long chain omega 3 fatty acids (from fish oils) would be preventive or promotional to mammary gland cancer in the offspring. Normal SV40 female mice were fed AIN 76 diets containing either 10% corn oil (control) or 5% of an omega 3 fatty acid concentrate + 5% canola oil. Females were then mated with C(3)1 TAg transgenic mice. Transgene hemizygous offspring were the experimental mice not the original SV40 female mice. On a normal diet the hemizygous mice are expected to have about 100% tumor incidence by 150 days of age. At weaning (3 weeks) pups were randomized to either the corn oil or the fish oil diet, 15-17 mice per group. At 140 days of age, mice never exposed to fish oil (C/C group) had a significantly higher incidence and multiplicity of mammary gland tumors than mice exposed to fish oil throughout life (F/F group). Mice exposed to fish oil during a portion of life (C/F or F/C) had intermediate incidences and multiplicities. Interestingly, omega 3 in the maternal diet alone decreased tumor multiplicity by 50% compared to no omega 3, even when the mouse received a control diet after weaning. If a mouse, developed a tumor the mean tumor masses were not significantly different though the F/F group had a much smaller mean tumor mass. Adequate omega 3 fatty acids in the maternal diet may reduce risk for mammary gland cancer in the offspring. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1855. doi:10.1158/1538-7445.AM2011-1855

Inhibition of angiogenesis of LCI-D20 hepatocellular carcinoma by metronomic chemotherapy of S-1

To investigate the role of metronomic chemotherapy of S-1 on angiogenesis of hepatocellular carcinoma in animal model. S-1 was dissolved in a 0.5% (w/v) HPMC solution. 30 LCI-D20 were randomly devided into five groups: control group(O), 10 mg * kg(-1) * d(-1) S-1 group (A), 1 mg * kg(-1) * d(-1) S-1 group (B), 0.5 mg * kg(-1) * d(-1) S-1 group (C) and 0.25 mg * kg(-1) * d S-1 group (D). 28 days after the treatment with 0.5% (w/v) HPMC solution, tumors in LCI-D20 mice were moved out. Tumor mass was measured and microvessel density (MVD) was used to evaluate angiogenesis in tumor. The cellular apoptosis was determined using flow cytometry. The expression of VEGF, bFGF and TSP-1 was measured by RT-PCR. The mean tumor mass was 2.01, 0.38, 1.12, 1.38, 2.27 g in O, A, B, C, D group, respectively. The mean MVD was 39.57, 19.90, 5.93, 17.10, 29.53 in O, A, B, C, D respectively. The mean tumor cellular apoptosis rate was 4.08%, 44.37%, 31.73%, 19.83%, and 8.25% in O, A, B, C, D respectively. The expression of VEGF and bFGF in O group was highest, and A was slightly low, and C and D taked the third place, and B was the lowst; The expression of TSP-1 in B was highest, and C and D were slightly low, and A taked the third place, and O was the lowst. Metronomic chemotherapy of S-1 destabilizes pre-existing tumor vasculature and inhibits ongoing angiogenesis.

Suppression of mammary gland carcinogenesis by post-initiation treatment of rats with tamoxifen or indole-3-carbinol or their combination

This study examined whether suppression of mammary gland carcinogenesis elicited by low doses of tamoxifen (TAM) can be enhanced by concomitant treatment of rats with indole-3-carbinol (I3C), a component of cruciferous vegetables and a dietary supplement used for its putative antiestrogenicity. Two weeks after one oral dose of 7,12-dimethylbenz[a]anthracene (DMBA) at 65 mg/kg body weight, female Sprague-Dawley rats started treatment with TAM (10 microg/rat) by subcutaneous injection, I3C (250 mg/kg body weight) by oral gavage, TAM+I3C or their respective vehicles three times per week, for up to 20 weeks. Significant increases in the median latency of malignant mammary tumors and decreases in the mean tumor mass per rat were due to TAM. Significant decreases in the mean tumor number per rat in TAM, I3C and TAM+I3C-treated rats indicated a cooperative effect of the two compounds. In both DMBA-initiated and uninitiated rats, significant increases in the ratios of liver to body weight in I3C and TAM+I3C-treated groups coincided with I3C-dependent increases of hepatic cytochrome P450 levels and activities (1A1, 1A2 and 2B1/2). The ratios of uterus to body weight decreased with the number of treatments and the decreases effected by TAM were greater than those by I3C. The levels of circulating estrone were increased in response to I3C treatment and were greater in DMBA-initiated rats than in uninitiated rats, which may contribute to the preventive effect of I3C. Chemoprevention may be accomplished through up-regulation of apoptotic enzyme (caspase) activities in the mammary gland or mammary tumors. Treatment with TAM, I3C or TAM+I3C had no effect on caspase-3&7, caspase-6, caspase-8 and caspase-9 activities in the mammary tumors or mammary gland of tumor-bearing rats or that of uninitiated rats. In the mammary gland of DMBA-initiated tumor-free rats, however, I3C treatment increased the levels of caspase-3&7 and caspase-9 activities, suggesting an I3C-mediated protective effect. Even though I3C alone is a much less effective suppressing agent of mammary carcinogenesis than TAM, I3C in combination with TAM does not weaken but may foster the benefits of chemoprevention with TAM.

Effects of epidermal growth factor on the growth of human gastric cancer cell and the implanted tumor of nude mice.

Epidermal growth factor (EGF) plays an important role in the regulation of gastrointestinal tissue growth and development, and it can stimulate epithelial proliferation, cell differentiation and growth. It has been established that the EGF can promote gastric cytoprotection and ulcer healing. But the potential ability of EGF to regulate the gastric cancer growth is unknown. This study is to investigate the influence of EGF on human gastric cancer cell and the implanted tumor growth of nude mice. The cell growth rates of human gastric adenocarcinoma cell lines MKN-28, MKN-45, SGC-7901 and normal human gastric epithelial cells 3T3 were assessed when incubated with recombinant human EGF (rhEGF, 0.05, 0.1, 0.5, 1.0, 10, 50, 100 mg.L(-1)) using MTT method. The cells of MKN-28, MKN-45, SGC-7901 (gastric cancer tissue 1.5mm(3)) were implanted in the BALB/cA nude mice for 10 days. The EGF was given intraperitoneally (15, 30, 60 microg.kg(-1)) for 3 weeks. The body weights of the tumor-bearing animals and their tumor mass were measured afterwards to assess the mitogenic effect of rhEGF in the nude mice. Within the concentration range of 0.05-100mg.L(-1), rhEGF could increase the cell growth of normal 3T3 cells (cell growth rate 100% vs 102.8%, P<0.05), but partially restrain the gastric cancer cell growth. The latter effect was related to cell differentiation. In 15-60 microg/kg rhEGF groups, the mean implanted tumor mass of MKN-28 cell were 1.75 g, 1.91 g, 2.08 g/NS group 1.97 g (P>0.05), the mean tumor mass of SGC-7901 cell were 1.53 g, 1.07 g, 1.20 g/NS group 1.07 g (P>0.05), and for MKN-45 cell, the tumor mass were respectively 1.92 g, 1.29 g, 1.77 /NS group 1.82 g (P>0.05). So rhEGF had no obvious effect on implanted MKN-28, SGC-7901 and MKN-45 tumor growth. EGF has no stimulating effect on the human gastric cancer cell growth neither in vitro nor in vivo.

Intratumoral injection of lipopolysaccharide causes regression of subcutaneously implanted mouse glioblastoma multiforme.

Anecdotal reports documented extended survival times for patients who developed infections at the site of resection of malignant gliomas. Hypothesized mechanisms for this phenomenon include immune responses triggered by lipopolysaccharide (LPS). This investigation assessed whether LPS could produce tumor regression in an in vivo model of malignant glioma. Delayed brain tumor cells (2 x 10(6)) were injected subcutaneously into female BALB/c mice. LPS (300-500 microg) was injected intratumorally or subcutaneously at a contralateral site on Days 10, 17, and 24. Control animals received phosphate-buffered saline intratumorally or subcutaneously. Mice were killed on Day 28, and tumors were removed. Mean tumor masses for control animals and the two LPS-treated groups (intratumoral or contralateral subcutaneous treatment) were compared. Histological assessments of treated and control tumors were performed. Complete or nearly total tumor regression was achieved in all 20 mice with subcutaneous delayed brain tumor cell tumors treated intratumorally with 400 microg of LPS (mean tumor mass of 0.09 +/- 0.38 g versus 2.42 +/- 2.46 g for control animals, P < 0.0001). Intratumoral administration of 300 microg of LPS or subcutaneous injection of 300 or 400 microg of LPS at a contralateral site resulted in less consistent regression of subcutaneous tumors. Administration of 500 microg of LPS resulted in tumor regression similar to that observed with lower doses but was limited by treatment-related deaths in 40% of animals. Histological assessment revealed lymphocytic infiltration of LPS-treated tumors. Intratumoral injections of LPS caused dramatic regression of subcutaneously implanted delayed brain tumor cell mouse gliomas. Investigation of this antitumoral effect may improve treatment responses for patients with malignant gliomas.

Sodium hyaluronate carboxymethylcellulose-based bioresorbable membrane (Seprafilm)--does it affect tumor implantation at abdominal wound sites?

This study examines the effects of a sodium hyaluronate-based bioresorbable membrane (Seprafilm) on tumor implantation at surgical wound and laparoscopic trocar sites. GW-39, an established human colon cancer line carried in immunocompetent golden Syrian hamsters was used as the experimental model. Under general anesthesia, a 2-cm midline incision was made to allow placement of four 5-mm abdominal trocars. Hamsters were then randomly assigned to preSeprafilm, postSeprafilm, and control (no Seprafilm) groups. In the preSeprafilm group 0.5 ml of a 5 percent (vol/vol) suspension of the GW-39 tumor cells (approximately 1.675 x 10(6) cells) was injected into the abdomen of each hamster via midline incision. Trocars were removed, the wounds were closed, and 1 cm2 of Seprafilm was placed on the peritoneal surface of each trocar site. In the postSeprafilm group the membrane was placed at each site before injection of tumor cells. The control group did not receive Seprafilm. The animals were killed after seven weeks, and the abdominal wound sites were excised. Sites without gross tumor underwent histologic evaluation. One hundred thirty-two animals were randomly assigned to the three groups. The preSeprafilm group had an 87 percent tumor implantation rate. The postSeprafilm group had a 90 percent tumor implantation rate. The control group had an 88 percent tumor implantation rate. Chi squared analysis demonstrated that these total tumor implant rates and mean tumor mass were similar at all wound sites and between groups. No toxicity was observed in any of the experimental groups. Sodium hyaluronate-based bioresorbable membrane (Seprafilm) does not influence GW-39 human colon cancer implantation at abdominal wound sites in this hamster model.

Antitumor activity of triptolide against cholangiocarcinoma growth in vitro and in hamsters

One of the diverse biological activities of triptolide, a diterpene from Tripterygium wilfordii, is its antitumor effect. We recently reported its in vitro cytotoxicity against several cultured tumor cell lines. Limited availability of purified fraction has prevented detailed investigation on its antitumor activity. In the present study, we showed by in vitro cytotoxicity assay and in vivo inhibition of tumor growth in hamsters that the triptolide was also highly effective against cholangiocarcinoma, a highly fatal tumor predominantly occurring in developing countries. Its ED 50 for these hamster cholangiocarcinoma cell lines was found to be as low as 0.05 μg/ml. The compound was highly potent in the induction of apoptotic death in these tumor cells. DNA fragmentation and disintegrating apoptotic cells could be observed within 24 h of exposure to 0.5 μg/ml triptolide. The compound was tested against the growth of cholangiocarcinoma in a hamster model. A significant growth inhibition ( P<0.05) was noted in triptolide-treated hamsters (each of the 10 animals received 10 injections for a total of 1.2 mg/animal). At the time of sacrifice 1 month after the initial injection, the mean tumor mass of the treated group was only 20–25% of that of the control group.

Role of epidermal-growth-factor receptor in tumor progression in transformed human mammary epithelial cells.

The presence of epidermal-growth-factor receptors (EGFR) and of its ligands (TGFalpha and amphiregulin) in breast-cancer tissues suggests that they play a paracrine/autocrine role in tumor growth or progression. This hypothesis was tested on 3 cell lines, S2T2, NS2T2A and NS2T2A1. These epithelial cells are derived from a normal human breast-epithelial-cell culture transformed by SV40-T Ag, are of the same clonal origin, have respectively increasing levels of EGFR, TGFalpha, amphiregulin and of thymidine-kinase activity associated with increasing tumorigenic potential in nude mice (tumor intake and tumor volume). The monoclonal antibody MAb 425, which blocks ligands interaction with EGFR, reduced by more than 90% anchorage-independent growth of the most tumorigenic cells, NS2T2A1. Another anti-EGFR MAb, 528, reduced to 25% of controls the mean tumor mass after NS2T2A1 grafting in mice. Anti-sense RNA expression of EGFR in these cells confirmed the importance of this receptor in tumor progression, since it reduced significantly the tumor volume and tumor weight of NS2T2A1 cells to 16% of those in mock-transfected control cells.

Role of epidermal‐growth‐factor receptor in tumor progression in transformed human mammary epithelial cells

The presence of epidermal-growth-factor receptors (EGFR) and of its ligands (TGFα and amphiregulin) in breast-cancer tissues suggests that they play a paracrine/autocrine role in tumor growth or progression. This hypothesis was tested on 3 cell lines, S2T2, NS2T2A and NS2T2A1. These epithelial cells are derived from a normal human breast-epithelial-cell culture transformed by SV40-T Ag, are of the same clonal origin, have respectively increasing levels of EGFR, TGFα, amphiregulin and of thymidine-kinase activity associated with increasing tumorigenic potential in nude mice (tumor intake and tumor volume). The monoclonal antibody MAb 425, which blocks ligands interaction with EGFR, reduced by more than 90% anchorage-independent growth of the most tumorigenic cells, NS2T2A1. Another anti-EGFR MAb, 528, reduced to 25% of controls the mean tumor mass after NS2T2A1 grafting in mice. Anti-sense RNA expression of EGFR in these cells confirmed the importance of this receptor in tumor progression, since it reduced significantly the tumor volume and tumor weight of NS2T2A1 cells to 16% of those in mock-transfected control cells. Int. J. Cancer 78:112–119, 1998.© 1998 Wiley-Liss, Inc.

Local treatment of abdominal wound reduces tumor implantation.

Pneumoperitoneum increases the trocar-site tumor implantation rate using a human colon cancer cell line in a hamster model. The purpose of this study was to determine whether local treatment of trocar sites with potential tumoricidal agents can inhibit tumor implantation after pneumoperitoneum. GW-39 human colon cancer cells (0.5 ml of 2.5% v/v; 8.0 x 10(5) cells) were injected throughout the abdomen of 133 Golden Syrian hamsters through a midline incision. The animals were randomized to receive either untreated 5-mm trocars in each abdominal quadrant (group I control, n = 49), trocars dipped in 10% povidone-iodine (group II, n = 53), or trocars coated with 1% silver sulfadiazine (group III, n = 51). The midline wounds were also coated with the respective agents before closing. Pneumoperitoneum was then maintained at 10 mmHg for 10 min, after which the trocar wounds were closed. In group II, the trocar sites were treated with a coat of povidone-iodine after the trocars were withdrawn and before closing. Gross and microscopic tumor implants were analyzed at 7 weeks postoperatively. The rate of tumor cell implantation at trocar sites was reduced from 93% (172/184) in the control group to 75% (126/168) and 78% (141/180) in groups II and III, respectively (P < 0.0001). Fewer palpable tumors were detected in groups II and III (40% and 23%, respectively) than in the control group (72%, P < 0.0001). Mean tumor mass in group III (0.4+/-0.1 g), but not in group II (1.0+/-0.2 g), was significantly less than that in the control group (1.3+/-0.1 g, P < 0.01). Overall tumor involvement of the larger midline wound was similar for all groups (I = 80%, II = 79%, III = 71%). However, palpable tumors were identified more frequently in group I (67%) than in groups II and III (43%, P < 0.05; 22%, P < 0.01, respectively). Pretreatment of abdominal wounds with povidone-iodine or silver sulfadiazine can reduce tumor implantation after pneumoperitoneum in a hamster model.

The effect of peritoneal air exposure on postoperative tumor growth.

Previous work has demonstrated that cell-mediated immune function is better preserved in rodents after laparoscopic than open surgery. The cause of this laparotomy-related immunosuppression is unclear. Some investigators have attributed it to the length of the incision; others, to peritoneal air exposure. It has also been shown that tumors in mice are more easily established and grow larger after sham laparotomy than after pneumoperitoneum. Lastly, the differences in tumor growth have been shown to be, at least in part, attributable to the immunosuppression that occurs after laparotomy. The purpose of this study was to determine if air pneumoperitoneum, presumably via immunosuppression related to peritoneal air exposure, is associated with increased tumor growth in the postoperative period. A total of 150 immunocompetent syngeneic mice received high-dose intradermal injections of mouse mammary carcinoma tumor cells. They were then randomized to undergo one of the following procedures: (a) anesthesia alone, (b) air insufflation (44 mm Hg), (c) CO2 insufflation, or (d) full laparotomy. No intraabdominal procedure was carried out. All procedures were 20 min long. After 12 days, the animals were killed and the mean tumor mass determined for each group. All animals grew tumors. There was no significant difference in the mean tumor size of the anesthesia control, CO2 insufflation, and air insufflation groups (p > 0.85 by ANOVA). However, the laparotomy group tumors were 1.5 times as large as those of the other three groups (p < 0.05 by ANOVA). In this model, air insufflation did not significantly affect postoperative tumor growth, nor did CO2 pneumoperitoneum. However, full laparotomy was associated with increased tumor growth.

In Vivo Modulation of N-myc Expression by Continuous Perfusion with an Antisense Oligonucleotide

In this study we investigated the in vivo efficacy of continuous subcutaneous perfusion of unmodified phosphodiester oligodeoxynucleotides. The in vitro sequelae of antisense inhibition of the target gene, N-myc, have been documented and include moderate growth inhibition without effects on myc expression, loss of secretogranin I expression, and morphologic alterations. We chose to use N-myc as a model target to determine if antisense effects observed in vitro can be reproduced in vivo. N-myc-expressing human neuroectodermal tumors were grown as subcutaneous xenografts in athymic mice. Antisense and sense oligodeoxynucleotides directed against N-myc were delivered to the vicinity of the tumor by a subcutaneously implanted microosmotic pump. Antisense treatment led to loss of N-myc protein from the tumor, as well as to the loss of the neuroendocrine differentiation marker protein secretogranin I. Myc protein expression remained unaffected. Mean tumor mass was reduced by 50% in antisense-treated animals, and antisense-treated tumors morphologically resembled antisense-transfected in vitro cell cultures. These results demonstrate that regional, in vivo perfusion of an unmodified oligonucleotide specifically downregulates gene expression in human tumor xenografts with concomitant effects on tumor phenotype and growth rate that correlate well with in vitro observations.