Phytochrome Mediated Responses in Agrobacterium fabrum: Growth, Motility and Plant Infection

The soil bacterium and plant pathogen Agrobacterium fabrum C58 has two phytochrome photoreceptors, Agp1 and Agp2. We found that plant infection and tumor induction by A. fabrum is down-regulated by light and that phytochrome knockout mutants of A. fabrum have diminished infection rates. The regulation pattern of infection matches with that of bacterial conjugation reported earlier, suggesting similar regulatory mechanisms. In the regulation of conjugation and plant infection, phytochromes are active in darkness. This is a major difference to plant phytochromes, which are typically active after irradiation. We also found that propagation and motility were affected in agp1− and agp2− knockout mutants, although propagation was not always affected by light. The regulatory patterns can partially but not completely be explained by modulated histidine kinase activities of Agp1 and Agp2. In a mass spectrometry-based proteomic study, 24 proteins were different between light and dark grown A. fabrum, whereas 382 proteins differed between wild type and phytochrome knockout mutants, pointing again to light independent roles of Agp1 and Agp2.

Interval Exercise Training Affects Expression of MCT-1, GLUT-1, PFK-1 and p53 as Key Metabolic Regulators on Azoxymethane-Induced Experimental Colon Cancer

Background Physical activity is one of the modulators of the cancer risk and survival factors. Therefore, the aim of this study was considering of pre and post interval exercise training on expression of MCT-1, GLUT-1, PFK-1 and p53 as a key metabolic regulators in azoxymethane-induced experimental colon cancer Methods Forty-eight male BALB/c mice were equally randomized into 6 groups: I: control (C); healthy animals, II: Exercise (E), III: tumor induction (T); animals received AOM for inducing colon cancer, IV: AOM + exercise (TE); animals with colon cancer underwent 8 weeks of the interval training protocol after tumor establishment, V: exercise + AOM (ET); animals received exercise protocol one week before AOM consumption, and (VI) exercise + AOM + exercise (ETE); animals received exercise protocol one week before and after AOM consumption (about 15 weeks) Groups III-VI were weekly-received AOM (as a carcinogenic agent, 10 mg/kg s.c) in three consecutive weeks to induce colon cancer. Interval exercise training was begun at 16–18 m/min, 10–14 min, 5 days/week for 6 weeks. Results The results showed that the tumor significantly increased mRNA and protein of MCT1 in the tumor group compared to the control group (p < 0.001), Also, exercise before and after tumor induction reduced MCT1 (and other glucose regulators) in the colon (respectively: p < 0.02 and p < 0.01). While the p53 gene decreased significantly in the tumor group compared to the control group (p < 0.01). Exercise before tumor induction and after tumor induction increased significantly (p < 0.01 and p < 0.04 respectively) in p53 compared to the tumor group. ETE group also downregulate the expression of glucose metabolism genes in colon tumor (p < 0.05). Conclusion Long-term aerobic interval exercise (pre, post, pre&post tumor) can contribute to inhibition of tumor progression and treatment against colon cancer. It seems that these preventive and treatment effects exercise training can attribute to the regulation of lactate and glucose transporters by up-regulation of p53 colorectal cancer cells.

Correction to: Influence of three BALB/c substrain backgrounds on the skin tumor induction efficacy to DMBA and TPA cotreatment

An amendment to this paper has been published and can be accessed via the original article.

Influence of three BALB/c substrain backgrounds on the skin tumor induction efficacy to DMBA and TPA cotreatment

Differences in responsiveness of BALB/c substrains have been investigated in various fields, including diabetes induction, corpus callosum deficiency, virus-induced demyelinating disease, aggressive behavior and osteonecrosis. However, induction efficacy of skin tumor remains untried. We therefore investigated the influence of BALB/c substrain backgrounds on the skin tumor induction efficacy in response to DMBA (7,12-Dimethylbenz[a]anthracene) and TPA (12-O-tetradecanoylphorbol-13-acetate) cotreatment. Alterations in the levels of tumor growth related factors, histopathological structure, and the expression to tumor related proteins were measured in three BALB/c substrains (BALB/cKorl, BALB/cA and BALB/cB) after exposure to DMBA (25 μg/kg) and three different doses of TPA (2, 4 and 8 μg/kg). The average number and induction efficacy of tumors in response to DMBA+TPA treatment were significantly greater in the BALB/cKorl substrain than in BALB/cA and BALB/cB. However, cotreatment with DMBA+TPA induced similar responses for body and organ weights of all three substrains. Few differences were detected in the serum analyzing factors, while similar responsiveness was observed for blood analyzing factors after DMBA+TPA treatment. Furthermore, the three BALB/c substrains exhibited similar patterns in their histopathological structure in DMBA+TPA-induced tumors. The expression levels of apoptotic proteins and tumor related proteins were constantly maintained in all three BALB/c substrains treated with DMBA+TPA. In addition, the responsiveness to cisplatin treatment was overall very similar in the three BALB/c substrains with DMBA+TPA-induced tumors. Taken together, these results indicate that genetic background of the three BALB/c substrains does not have a major effect on the DMBA+TPA-induced skin carcinogenesis and therapeutic responsiveness of cisplatin, except induction efficacy.

Tumor size distribution can yield valuable information on tumor growth and tumor control

In this work it is shown that tumor volume distributions, can yield valuable information on two completely different topics of cancer research. From the hypothesis that the intrinsic distributions of breast cancer volumes follows an exponential distribution, first the probability density function of tumor growth time was deduced. The resulting distribution of lag times can be used in tumor induction models instead of a fixed lag time to deduce the probability of tumor induction as a function of patient age. In a second step, the distribution of cancer volumes was used to model the variation of the clonogenic cell number for tumor control probability calculations for radiotherapy cancer patients. The integration of the volume variation into a Poisson-TCP model resulted in a logistic function which fits population averaged survival data of radiotherapy patients. To our knowledge this is the first direct derivation of a logistic TCP model for cohorts of patients from a Poisson TCP-model for individuals.

Induction of pancreatic neoplasia in the KRAS/TP53 Oncopig: preliminary report

ABSTRACTIntroductionFive-year survival (all patients) from pancreatic cancer (PC) is in the range of 10%, and has not changed substantially in decades. Current murine models may not adequately mimic human PC, and can be inadequate for device development, which all may contribute to the lack of progress in PC survival. We attempted PC induction in transgenic swine (expressing KRAS and TP53 mutants) with the ultimate goal of creating a more accurate model of PC.MethodsTransgenic Oncopigs (n = 16, malensrrc.missouri.edu; somatic LSL cassette with TP53R167H and KRASG12D) were injected via laparotomy with AdCre (1010 vp/mL) ± IL-8 (0.5-2 ng; a tumor induction adjunct facilitating adenoviral entry into epithelia and promoting local inflammation) into the main pancreatic duct (MPD; via duodenotomy) or duct to the isolated pancreatic connecting lobe (CL). Subjects were necropsied after ≤10 wk, followed by histology.ResultsA total of 16 OCM subjects underwent an induction procedure. Of these, 14 received pancreatic AdCre injection, and nine of these (64%) developed pancreatic tumor (10 if the very first subject which died prematurely is counted). All of these subjects expired within 2-4 weeks after the tumor induction procedure. All had a similar terminal course: failure to thrive, which was secondary to gastric outlet obstruction, which was secondary to a peripancreatic phlegmon, which was secondary to pancreatitis, which appeared to be secondary to tumor. One additional OCM (no. 1088) had a small amount of extrapancreatic tumor at necropsy when it was euthanized for pneumonia at day 113. None of the OCM subjects that underwent a control injection procedure (no AdCre) nor any of the WT littermates that underwent AdCre injection with or without IL-8 developed pancreatitis.ConclusionThis proof of principle study demonstrated that PC can be induced in the Oncopig, which has inducible expression of activated KRAS and inactive p53 under control of a floxed stop codon. However, induced subjects will need to live longer to yield a useable PC model. Addition of IL-8 may have contributed to the severe pancreatitis and early mortality. Future studies will focus on modulation of pancreatitis and optimization of the survival period.

Immunomodulatory effects of renin–angiotensin system inhibitors on T lymphocytes in mice with colorectal liver metastases

BackgroundIt is now recognized that many anticancer treatments positively modulate the antitumor immune response. Clinical and experimental studies have shown that inhibitors of the classical renin–angiotensin system (RAS) reduce tumor progression and are associated with better outcomes in patients with colorectal cancer. RAS components are expressed by most immune cells and adult hematopoietic cells, thus are potential targets for modulating tumor-infiltrating immune cells and can provide a mechanism of tumor control by the renin–angiotensin system inhibitors (RASi).AimTo investigate the effects of the RASi captopril on tumor T lymphocyte distribution in a mouse model of colorectal liver metastases.MethodsLiver metastases were established in a mouse model using an autologous colorectal cancer cell line. RASi (captopril 750 mg/kg) or carrier (saline) was administered to the mice daily via intraperitoneal injection, from day 1 post-tumor induction to endpoint (day 15 or 21 post-tumor induction). At the endpoint, tumor growth was determined, and lymphocyte infiltration and composition in the tumor and liver tissues were analyzed by flow cytometry and immunohistochemistry (IHC).ResultsCaptopril significantly decreased tumor viability and impaired metastatic growth. Analysis of infiltrating T cells into liver parenchyma and tumor tissues by IHC and flow cytometry showed that captopril significantly increased the infiltration of CD3+ T cells into both tissues at day 15 following tumor induction. Phenotypical analysis of CD45+ CD3+ T cells indicated that the major contributing phenotype to this influx is a CD4 and CD8 double-negative T cell (DNT) subtype, while CD4+ T cells decreased and CD8+ T cells remained unchanged. Captopril treatment also increased the expression of checkpoint receptor PD-1 on CD8+and DNT subsets .ConclusionCaptopril treatment modulates the immune response by increasing the infiltration and altering the phenotypical composition of T lymphocytes and may be a contributing mechanism for tumor control.