Effect of GM-CSF on tumor-specific immune response and antitumoral efficacy when combined with suicide gene therapy

e14610

Background: Suicide gene therapy is one of the promising treatment modalities in cancer treatment. Combination of an immunotherapy modality with suicide gene therapy would increase the tumor eradciating efficacy of either treatment strategy used alone. Methods: In the current study, we constructed adenoviral vectors carying ytosine deaminase (CD), granulocyte macrophage-colony stimulating factor (GM-CSF) vectors. We tested the in vitro efficacy of the vectors in both human and mouse tumor cell lines and in a syngeneic mouse model of colon cancer with tumor explants of CRL 2638 cells. Results: Our results show that the vectors carrying CD/GM-CSF transcription units are effective in terms of killing of tumor cells when 5-FC added. Addition of GM-CSF transgene induced a significant amount of GM-CSF secretion (250 pg/ml/105 cells) of infected cells. In the syngeneic colon cancer model, addition of GM-CSF significantly increased tumor-specific cellular immune response when compared to suicide gene therapy alone. (p<0.01). Likewise, GM-CSF addition caused a 8 times reduction in the ratio of Tregs infiltrating the tumor nodules (p<0.001). Accordingly, GM-CSF decreased the tumor growth by 2 times an d increased the median survival time by 50% (p<0.01). Conclusions: These impressive results of in-vitro cytotoxicity and encouraging results of in-vivo testing of the our newly constructed GM-CSF carrying vector suggest a potential for the use of the vector for the treament of established tumors by inducing tumor specific immune response.

No significant financial relationships to disclose.

Petrochemical wastewater odor treatment by biofiltration

The treatment of odorous pollutants by microorganisms on packed waste straw and cortex was investigated at the wastewater treatment plant of the Shanghai petrochemical factory. The removal efficiency of H(2)S, NH(3) and VOCs (volatile organic compounds) reached 98%, 91% and 90%, respectively after operation for one month at an empty bed retention time (EBRT) of 120s. The heterotrophic bacteria were found to be the dominant microorganism in the biofilter, while fungi and actinomycetes were also present. The bacteria were mostly identified as the members of the genus Bacillus (62.5% of cultured bacteria). The single strand conformation polymorphism (SSCP) results revealed that the genus Bacillus and Pseudomonas were the predominant bacteria. The microbial diversity gradually increased as the treatment progressed, which indicated that the microbial community in the biofilter became more stable upon pollutant removal. The scanning electron microscopy (SEM) was performed to evaluate the microorganism growth on the media. It was found that the waste straw and cortex were suitable for microorganism attachment and growth, and may have potential application in odor treatment.

The controlled synthesis of single-crystalline CdCO3 nanoparticles with different morphologies

Single crystalline CdCO3 low-dimensional nanostructures, such as nanowires, nanobelts, and nanorolls have been controlled synthesized through a convenient, low-temperature hydrothermal method. Moreover, the shape and diameter of low-dimensional CdCO3 nanostructures can be facilely controlled through adjusting the experiment factors. The influences of the ammonia concentration and temperature on the morphology of CdCO3 are investigated, and a possible mechanism involved adjustable growth properties from kinetic growth stage to thermodynamic growth stage has been discussed. This work has also provided a general, simple, and effective method to control the shape of other transition-metal carbonate.

Targeting of chemotherapy to Tie-2-receptor positive angiogenic endothelial cells of tumor vasculature

Abstract #902

Background: There are at least three types of cells in tumor tissue which express the Tie2 receptor (Tie2R): dividing vascular endothelial cells (TVECs), Tie2R-expressing monocytes (TEMs) and Tie2R-expressing mesenchymal progenitor cells (TMPCs).&#x2028; &#x2028; We tested if the targeting of chemotherapy to these classes of Tie2R positive cells could suppress tumor cell growth.&#x2028; Material and Methods: We constructed replication incompetent adenoviral vectors carrying the cytosine deaminase (CD) suicide gene driven by the mouse Tie2R transcriptional promoter and enhancer sequences. In these viruses, we inserted an RGD-4C peptide into the HI loop of the fiber knob domain of the vector to increase its transduction efficiency in TVECs. At the same time, we added two mutations (S408E and P409A) in the AB loop of the fiber, which ablated the CAR-binding ability of the vector. The resulting vector was named AdTie2RCD(MRGD).&#x2028; Results: In vitro viral infection assays involving the human umbilical vein endothelial cells (HUVECs) showed that the RGD-modified vectors have a higher transduction efficiency as compared with their adenoviral vector counterparts which have a wild type fiber protein. Mice carrying the rat Her-2-Neu positive N202 mouse breast cancer cells and the mouse B16 melanoma cells were treated with intravenous injections of Hetastarch and the AdTie2RCD(MRGD) vector followed by intraperitoneal injections of 5-Fluorocytosine (5-FC). The Hetastarch was given before the intraveinous infusion of the adenoviral vector in order to reduce the uptake of the adenoviral vector by the reticuloendothelial cell system. The Tie2R targeted chemotherapy sensitization vectors induced greater degrees of suppression of tumor cell growth than did the control group, achieved the similar treatment effect to its CMV promoter counterpart, but with less side effect.&#x2028; &#x2028; Histological analysis showed that these vectors specifically targeted the TVECs, TEMs and TMPCs through which they may have exerted cytotoxic effects in the presence of 5-FC on the tumor cells.&#x2028; Discussion: Our results showed that N202 breast cancer cell line is more responsive to the Tie2R-targeting therapy compared to B16 mouse melanoma cell line and the Tie2R-directed anti-angiogenic therapy deserves further study, in combination with other types of therapy to pave the way for future clinic trails.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 902.

Increasing tuberculosis case detection through intensive referral and tracing in Hunan, China

OBJECTIVE

To explore a feasible approach to increase case finding of tuberculosis (TB) through intensive referral and tracing of TB suspects and patients.

METHODS

A quasi-experimental study was conducted in three Chinese cities. A strategic referral and tracing system was developed for the local situation in Hunan, China. Data from a 1-year monitoring of referral, tracing and diagnosis of TB suspects/cases were used to assess outcomes.

RESULTS

Among 126 public general hospitals and clinics in 38 project counties, the 124 (98.4%) health facilities that participated referred an average of 10 TB suspects and cases to the TB dispensary every month. A total of 6364 suspects and 5759 cases were referred. Compared to the previous year, the number of TB suspects increased by 102.1%, from 25 719 to 51 967; the referral of TB suspects increased five-fold; 10 596 new smear-positive pulmonary tuberculosis (PTB) cases were identified; and the notification of new smear-positive PTB increased by 112.9%, from 27.1/100 000 before the project year to 57.7/100 000, a significantly higher percentage than that of non-project areas, which had a notification rate of 38.8/100 000.

CONCLUSION

Intensive referral and tracing of TB suspects/patients is a feasible and effective method of increasing case finding. Strengthening administrative interventions and incentives is essential to achieve project objectives.

NovaSil clay intervention in Ghanaians at high risk for aflatoxicosis: II. Reduction in biomarkers of aflatoxin exposure in blood and urine

The efficacy of NovaSil clay (NS) to reduce aflatoxin (AF) biomarkers of exposure was evaluated in 656 blood samples and 624 urine samples collected from study participants during a 3-month phase IIa clinical intervention trial in Ghana. NS was delivered before meals via capsules. Serum AFB (1)-albumin adduct was measured by radioimmunoassay and urinary AFM (1) metabolites were quantified by immunoaffinity-high-performance liquid chromatography (HPLC)-fluorescence methods. Levels of AFB (1) -albumin adduct in serum samples collected at baseline and at 1 month were similar (p = 0.2354 and p = 0.3645, respectively) among the placebo (PL), low dose (LD, 1.5 g NS day (-1)), and high dose (HD, 3.0 g NS day (-1)) groups. However, the levels of AFB (1)-albumin adduct at 3 months were significantly decreased in both the LD group (p < 0.0001) and the HD group (p < 0.0001) compared with levels in the PL group. Levels of AFM(1) in urine samples collected at baseline and at 1 month were not statistically different among the three study groups. However, a significant decrease (up to 58%) in the median level of AFM (1) in samples collected at 3 months was found in the HD group when compared with the median level in the PL group (p < 0.0391). In addition, significant effects were found for dose, time, and dose-time interaction with serum AFB(1)-albumin adduct and dose-time interaction with urinary AFM (1) metabolites. The results suggest that capsules containing NS clay can be used to reduce effectively the bioavailability of dietary AF based on a reduction of AF-specific biomarkers.

Optical parametric chirped-pulse amplification source suitable for seeding high-energy systems

A short-pulse source based on optical parametric chirped-pulse amplification (OPCPA) technology has been developed with properties that make it a suitable seed for a high-energy OPCPA system. This source generated a diffraction-limited pulse at 910 nm with a full bandwidth of > 165 nm and a spectrum having a transform-limited pulse duration of less than 15 fs. The technique has potential for generating bandwidths > 200 nm and pulse durations < 10 fs.

Exenatide prevents fat-induced insulin resistance and raises adiponectin expression and plasma levels

BACKGROUND

Exenatide (exendin-4) can reduce blood glucose levels, increase insulin secretion and improve insulin sensitivity through mechanisms that are not completely understood.

METHODS

In the present study, we examined the effects of exenatide treatment on glucose tolerance (intravenous glucose tolerance test), insulin sensitivity (euglycaemic-hyperinsulinaemic clamps), insulin signalling (insulin receptor substrate 1 tyrosine phosphorylation) and adipocytokine levels (visfatin and adiponectin) in high fat-fed rats.

RESULTS

Administration of exenatide (0.5 or 2.0 mug/kg twice daily x 6 weeks) prevented high-fat diet (HFD)-induced increases in body weight, plasma free fatty acids, triglycerides and total cholesterol. Exenatide also prevented HFD-induced deterioration in peripheral and hepatic insulin sensitivity, insulin clearance, glucose tolerance and decreased tyrosine phosphorylation of insulin receptor substrate-1 (IRS-1) in fat and skeletal muscles. Interestingly, plasma visfatin levels decreased in exenatide-treated rats, whereas expression and plasma levels of adiponectin increased.

CONCLUSIONS

These results indicate that chronic exenatide treatment enhances insulin sensitivity and protects against high fat-induced insulin resistance.

Endogenous hydrogen sulfide is involved in regulation of respiration in medullary slice of neonatal rats

The purpose of the present study was to verify our assumption that rhythmic respiratory activity may be regulated by endogenous hydrogen sulfide (H(2)S) in the medullary slices of neonatal rats. We found that a moderate concentration of donor of H(2)S, NaHS, mainly induced diphasic respiratory responses indicated by changes of discharge frequency (DF) of hypoglossal rootlets, an initial inhibitory stage followed by a later excitatory one. Cystathionine beta-synthase (CBS) substrate, cysteine (CYS), exerted similar effects. CBS inhibitor, NH(2)OH, could eliminate both inhibitory and excitatory effects in the two stages induced by CYS. K(ATP) channel blocker, glibenclamide (Gl), could eliminate the decrease in DF in the initial stage, but not the increase in the later one. On the other hand, adenyl cyclase (AC) inhibitor, SQ-22536 (SQ) could eliminate the increase in DF in the later stage, but not the decrease in the initial one, of the rootlets caused by NaHS. Co-application of Gl and SQ eliminated both inhibitory and excitatory effect induced by NaHS. The cAMP level was increased in the later stage but not in the initial one by NaHS, and the increase in the cAMP level could be eliminated by SQ. It can be concluded that the endogenous H(2)S could be produced through the CBS-H(2)S pathway and could be involved in the control of the central rhythmic respiration in the in vitro medullary slices of neonatal rats by opening K(ATP) channels and activating AC-cAMP pathway of the neurons.

Characterization of PacMetUT1, a recently isolated human prostate cancer cell line

BACKGROUND

Existing prostate cancer cell lines have limitations.

METHODS

Cells were characterized using Western blotting, immunohistochemistry, invasion into Matrigel, and by studying xenograft tumors.

RESULTS

We describe a cell line (PacMetUT1) isolated from a lymph node of a 57-year-old male with prostate cancer. Compared to existing prostate cancer cell lines, the growth rate of PacMetUT1 xenograft tumors is slower with tumors occurring at injection sites and with metastases to lung and liver. Androgen receptor (AR) was detected in vivo by Western blotting and the cells responded to methyltrienolone (R1881). PacMetUT1 cells are more invasive in Matrigel than DU-145, PC-3, and LNCaP cells, and showed greater anchorage-independent growth in soft agar. The cells do not express prostate specific antigen (PSA) in vitro or in xenografts. However, the green fluorescent protein (GFP) gene was introduced and stably expressed in PacMetUT1 cells, allowing tumor imaging in vivo. Xenograft tumors show epithelial features and are positive for keratin, epithelial membrane antigen, EGF receptor, and E cadherin. In contrast, fibroblast markers vimentin, desmin, and Factor VIII, were negative. Karyotyping showed losses of 6p, 7q, 8p, 18q, and 22q, and gains of 8q and 9q; additional genetic material was observed at 2q and 12p.

CONCLUSION

The PacMetUT1 cell line allows metastases to be assessed using a single animal model. Because of its slower growth, PacMetUT1 more closely mimics the human disease. Studies of tumor progression or metastasis can be conducted over a longer period of time.

Expression of claudin-2 in the multistage process of gastric carcinogenesis

OBJECTIVE

Claudin-2 is an important component of the tight junction (TJ) of epithelial cells, and its protein expression between many tumours is significantly different. It is unclear if Claudin-2 overexpression is a trigger or a consequence during carcinogenesis. The multistage tissues of gastric carcinogenesis provides us a valuable model for determining tumourigenicity.

METHODS

This paper investigated, for the first time, claudin-2 expression in the pathological paraffin tissues of sinus ventriculi from gastroscopic biopsy. To determine claudin-2 expression in gastric carcinogenesis by immunochemical ABC technique.

RESULTS

Altogether, 108 chronic superficial gastritis, 55 chronic atrophic gastritis, 109 intestinal-type metaplasia, 93 dysplasia and 52 gastric intestinal-type adenocarcinoma samples were analyzed. Results indicated that the percentage of claudin-2-positive cases was 0% for chronic superficial gastritis (0/108), 0% for chronic atrophic gastritis (0/55), 0% for intestinal-type metaplasia (0/109), 35.87% for dysplasia (33/92), and 73.47% for gastric intestinal-type adenocarcinoma (36/49) respectively, primarily in the cell membrane, and gradually increased in the multistage process of gastric carcinogenesis (P<0.001).

CONCLUSIONS

This suggests that claudin-2 protein overexpression may be closely correlated to gastric carcinogenesis.