CCL5 Neutralization Restricts Cancer Growth and Potentiates the Targeting of PDGFRβ in Colorectal Carcinoma

Increased CCL5 levels are markers of an unfavourable outcome in patients with melanoma, breast, cervical, prostate, gastric or pancreatic cancer. Here, we have assessed the role played by CCL5/CCR5 interactions in the development of colon cancer. To do so, we have examined a number of human colorectal carcinoma clinical specimens and found CCL5 and its receptors over-expressed within primary as well as liver and pulmonary metastases of patients compared to healthy tissues. In vitro, CCL5 increased the growth and migratory responses of colon cancer cells from both human and mouse origins. In addition, systemic treatment of mice with CCL5-directed antibodies reduced the extent of development of subcutaneous colon tumors, of liver metastases and of peritoneal carcinosis. Consistently, we found increased numbers of CD45-immunoreactive cells within the stroma of the remaining lesions as well as at the interface with the healthy tissue. In contrast, selective targeting of CCR5 through administration of TAK-779, a CCR5 antagonist, only partially compromised colon cancer progression. Furthermore, CCL5 neutralization rendered the tumors more sensitive to a PDGFRβ-directed strategy in mice, this combination regimen offering the greatest protection against liver metastases and suppressing macroscopic peritoneal carcinosis. Collectively, our data demonstrate the involvement of CCL5 in the pathogenesis of colorectal carcinoma and point to its potential value as a therapeutic target

Normalisation to Blood Activity Is Required for the Accurate Quantification of Na/I Symporter Ectopic Expression by SPECT/CT in Individual Subjects

The utilisation of the Na/I symporter (NIS) and associated radiotracers as a reporter system for imaging gene expression is now reaching the clinical setting in cancer gene therapy applications. However, a formal assessment of the methodology in terms of normalisation of the data still remains to be performed, particularly in the context of the assessment of activities in individual subjects in longitudinal studies. In this context, we administered to mice a recombinant, replication-incompetent adenovirus encoding rat NIS, or a human colorectal carcinoma cell line (HT29) encoding mouse NIS. We used 99mTc pertechnetate as a radiotracer for SPECT/CT imaging to determine the pattern of ectopic NIS expression in longitudinal kinetic studies. Some animals of the cohort were culled and NIS expression was measured by quantitative RT-PCR and immunohistochemistry. The radioactive content of some liver biopsies was also measured ex vivo. Our results show that in longitudinal studies involving datasets taken from individual mice, the presentation of non-normalised data (activity expressed as %ID/g or %ID/cc) leads to ‘noisy’, and sometimes incoherent, results. This variability is due to the fact that the blood pertechnetate concentration can vary up to three-fold from day to day. Normalisation of these data with blood activities corrects for these inconsistencies. We advocate that, blood pertechnetate activity should be determined and used to normalise the activity measured in the organ/region of interest that expresses NIS ectopically. Considering that NIS imaging has already reached the clinical setting in the context of cancer gene therapy, this normalisation may be essential in order to obtain accurate and predictive information in future longitudinal clinical studies in biotherapy

Les copolymères à blocs pour le transfert de gènes dans le muscle squelettique

Le transfert de gènes dans le muscle squelettique à l'aide de vecteurs synthétiques représente une stratégie prometteuse pour le traitement de maladies génétiques héréditaires ou acquises. Parmi les vecteurs synthétiques utilisés pour le transfert de gènes dans cet organe, les copolymères à blocs présentent de nombreux avantages en terme d'efficacité et de toxicité. Ces vecteurs se sont révélés être très efficaces pour permettre l'expression de la dystrophine et la restauration du complexe dystroglycoprotéique membranaire chez la souris myopathe. Le muscle squelettique peut également être utilisé comme organe sécréteur de protéines thérapeutiques systémiques. Le transfert du gène de l'érythropoïétine à l'aide de copolymères à blocs a permis la correction de l'anémie chez un modèle de souris en insuffisance rénale chronique. L'utilisation d'un promoteur inductible par la doxycycline permet de réguler l'expression du gène de l'érythropoïétine jusqu'à 4 mois après le transfert de gène avant la mise en place d'une réaction immunitaire contre le transactivateur chimérique. La répétition d'injections intramusculaires du gène codant l'érythropoïétine formulé avec des copolymères à blocs, permet d'adapter durablement le niveau de sécrétion d'érythropoïétineThere is conclusive evidence that muscle gene therapy using synthetic vectors can lead to real clinical benefit for treatment of genetic or acquired diseases. Block copolymers are new efficient and non toxic vectors used for gene transfer in this organ. These vectors have been used to restore efficiently the expression ofdystrophin and led to the restoration of the dystrophin proteins complex in dystrophic mice. This approach using new synthetic vectors is particularly appropriate to obtain long-term circulating therapeutic protein. Intramuscular injections of a plasmid DNA encoding this protein formulated with block copolymer prevent or correct anemia induced by acquired renal failure in adenine treated mice. The temporal regulation of erythropoietin gene expression was obtained by the use of a tetracyclin inducible promoter. However, an immune response against the chimeric transactivator was observed 4 months post-injection stopping the EPO synthesis. The development of a protocol consisting in repeated intramuscular injections of block copolymer/DNA formulations provides an efficient method for a durable and an adjustable secretion of erythropoietin.NANTES-BU Médecine pharmacie (441092101) / SudocPARIS-BIUP (751062107) / SudocSudocFranceF

Adrenal gland infection by serotype 5 adenovirus requires coagulation factors.

Recombinant, replication-deficient serotype 5 adenovirus infects the liver upon in vivo, systemic injection in rodents. This infection requires the binding of factor X to the capsid of this adenovirus. Another organ, the adrenal gland is also infected upon systemic administration of Ad, however, whether this infection is dependent on the cocksackie adenovirus receptor (CAR) or depends on the binding of factor X to the viral capsid remained to be determined. In the present work, we have used a pharmacological agent (warfarin) as well as recombinant adenoviruses lacking the binding site of Factor X to elucidate this mechanism in mice. We demonstrate that, as observed in the liver, adenovirus infection of the adrenal glands in vivo requires Factor X. Considering that the level of transduction of the adrenal glands is well-below that of the liver and that capsid-modified adenoviruses are unlikely to selectively infect the adrenal glands, we have used single-photon emission computed tomography (SPECT) imaging of gene expression to determine whether local virus administration (direct injection in the kidney) could increase gene transfer to the adrenal glands. We demonstrate that direct injection of the virus in the kidney increases gene transfer in the adrenal gland but liver transduction remains important. These observations strongly suggest that serotype 5 adenovirus uses a similar mechanism to infect liver and adrenal gland and that selective transgene expression in the latter is more likely to be achieved through transcriptional targeting

Localization of the kidneys using ^99mTc-DMSA.

<p>Mice were injected intra-peritoneally with 95 MBq of ^99mTc-DMSA. Five hours later, the animals were anaesthetized and SPECT/CT scans performed. A) Transverse, coronal and sagittal sections centered on the kidneys. B) Volume rendering of the whole animal in which the kidneys appear in yellow. Legend: K: kidney, L: left, post: posterior side of the animal.</p

Influence of Factor X on adenovirus transduction in warfarin-treated mice.

<p>A replication-deficient recombinant adenovirus encoding the Lac-Z gene (6×10⁸ PFU) was injected in warfarin-pretreated animals (n = 7) or warfarin-pre-treated, factor X-complemented animals (n = 5). Forty-eight hours later, liver biopsies or adrenal glands were collected. A) Whole liver were stained for β-galactosidase expression. B: Total RNA were extracted from the adrenal glands (two glands from the same animal were pooled), reversed-transcribed and subjected to quantitative PCR to detect LacZ expression or 18S RNA. The ratio LacZ/18S of adrenal glands collected from warfarin-pre-treated, factor X-complemented animals injected with adenovirus was set at 100%. The data presented are means+SEM. Statistical analysis: Student t test (Prism, Graph-Pad softwares).</p

Figure 2

<p><b>Effect of warfarin pre-treatment on adenoviral transgene expression.</b> A replication-deficient recombinant adenovirus encoding the Lac-Z gene (6×10⁸ PFU) was injected in control- (Adenovirus) or warfarin-pretreated animals (Warfarin and Adenovirus). Twenty-four hours later, liver biopsies or adrenal glands were collected. A: Measurement of the β-galactosidase protein in the samples was performed. The data presented are percentages of mean +/− SEM from untreated animals (n = 2), adenovirus-injected animals (n = 10) and adenovirus-injected animals, pre-treated with warfarin (n = 10). 100% represents the average of β-galactosidase activity in the adrenal glands (100% = 7584 β-gal units/mg of protein) or liver (100% = 24805 β-gal units/mg of protein) of adenovirus-injected animals. Statistical test: ANOVA (Prism, Graph-Pad softwares). B) Total RNA were collected from individual adrenal glands or liver biopsies, reversed-transcribed and subjected to quantitative PCR to detect LacZ or 18S RNA. The ratio LacZ/18S of liver or adrenal glands collected from animals injected with adenovirus was set at 100%. Data presented are duplicate determinations from a single adrenal gland and liver biopsy and is representative of 4 independent experiments.</p

Visualization of gene transfer in the liver upon intra-renal injection: Effect of warfarin.

<p>Direct injection of 5×10⁸ PFU Ad-CMV-rNIS in the left kidney was performed on control (A) or warfarin-treated mice (B). Forty-eight hours later, the mice were anaesthetized and SPECT/CT scans performed. The transverse, coronal and sagittal sections presented are centered on the liver. Legend: L: liver, S: Stomach.</p

Effect of warfarin pre-treatment on adenoviral transgene expression following intra-renal administration.

<p>Ad-CMV-rNIS, a replication-deficient recombinant adenovirus encoding the NIS gene (5×10⁸ PFU) was injected into the left kidney of control- (Adenovirus) or warfarin-pretreated animals (Warfarin and Adenovirus). Fourty-eight hours later, liver biopsies and adrenal glands were collected. Total RNA were collected from individual adrenal glands (on the left kidney) or liver biopsies, reversed-transcribed and subjected to quantitative PCR to detect rNIS expression or GAPDH RNA. The ratio rNIS/GAPDH of liver or adrenal glands collected from animals injected with adenovirus was set at 100%. Data presented are triplicate determinations from three adrenal gland and liver biopsies. The data presented are means+SEM. Statistical analysis: Student t test (Prizm, Graph-Pad softwares). **p≤0,01.</p