Expanded Alternatives of CRISPR-Cas9 Applications in Immunotherapy of Colorectal Cancer

Immunotherapy for colorectal cancer (CRC) is limited to patients with advanced disease who have already undergone first-line chemotherapy and whose tumors exhibit microsatellite instability. Novel technical strategies are required to enhance therapeutic options and achieve a more robust immunological response. Therefore, exploring gene analysis and manipulation at the molecular level can further accelerate the development of advanced technologies to address these challenges. The emergence of advanced genome editing technology, particularly of clustered, regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein (Cas) 9, holds promise in expanding the boundaries of cancer immunotherapy. In this manuscript, we provide a comprehensive review of the applications and perspectives of CRISPR technology in improving the design, generation, and efficiency of current immunotherapies, focusing on solid tumors such as colorectal cancer, where these approaches have not been as successful as in hematological conditions.

Molecular mechanisms involved in fetal programming and disease origin in adulthood

Fetal programming occurs during the gestational age when exposure to environmental stimuli can cause long-term changes in the fetus, predisposing it to develop chronic non-communicable diseases (CNCD) in adulthood. Herein, we summarized the role of low-calorie or high-fat diets during pregnancy as fetal programming agents that induce intrauterine growth restriction (IUGR), amplified de novo lipogenesis, and increased amino acid transport to the placenta, which favor the CNCD onset in the offspring. We also outlined how maternal obesity and gestational diabetes act as fetal programming stimuli by reducing iron absorption and oxygen transport to the fetus, stimulating inflammatory pathways that boost neurological disorders and CNCD in the progeny. Moreover, we reviewed the mechanisms through which fetal hypoxia elevates the offspring's risk of developing hypertension and chronic kidney disease in adult life by unbalancing the renin-angiotensin system and promoting kidney cell apoptosis. Finally, we examined how inadequate vitamin B12 and folic acid consumption during pregnancy programs the fetus to greater adiposity, insulin resistance, and glucose intolerance in adulthood. A better understanding of the fetal programming mechanisms may help us reduce the onset of insulin resistance, glucose intolerance, dyslipidemia, obesity, hypertension, diabetes mellitus, and other CNCD in the offspring during adulthood.

M2 macrophage immunotherapy abolishes glucose intolerance by increasing IL-10 expression and AKT activation

Aim: Glucose intolerance associates with M1/M2 macrophage unbalance. We thus wanted to examine the effect of M2 macrophage administration on mouse model of glucose intolerance. Materials & methods: C57BL/6 mice fed a high-fat diet (HFD) for 12 weeks and then received thrice 20 mg/kg streptozotocin (HFD-GI). Bone marrow-derived stem cells were collected from donor mice and differentiated/activated into M2 macrophages for intraperitoneal administration into HFD-GI mice. Results: M2 macrophage treatment abolished glucose intolerance independently of obesity. M2 macrophage administration increased IL-10 in visceral adipose tissue and serum, but showed no effect on serum insulin. While nitric oxide synthase-2 and arginase-1 remained unaltered, M2 macrophage treatment restored AKT phosphorylation in visceral adipose tissue. Conclusion: M2 macrophage treatment abolishes glucose intolerance by increasing IL-10 and phosphorylated AKT.

Down-modulation of colitis-associated colorectal cancer development by treatment with helminth-derived molecules

A role for chronic inflammation in tumor development has been well established and supported in both, animal and epidemiological studies. A classic association between inflammation and cancer is colitis-associated colorectal cancer (CAC). Helminth infections and helminth-derived molecules have been recognized as inducers of immunoregulation. Taenia crassiceps modulates inflammatory diseases such as type 1 diabetes, colitis, and autoimmune encephalomyelitis. Here we analyzed the pathophysiologic implication of T. crassiceps excreted/secreted (TcES) products on CAC development. CAC was induced in BALB/c mice with azoxymethane followed by 3 cycles of 2% dextran sodium sulfate exposure to elicit intestinal inflammation. After cycle 1, mice received i.p. TcES (200 μg/mouse 3-times/week) until the end of the experiment. On days 20, 40 and 68 after CAC induction mice were killed to evaluate colonic inflammation, proliferation, and tumorigenesis. Untreated mice developed tumors as early as 20 days after CAC induction and by the end of the experiment, 100% of these mice displayed tumors. In contrast, only 30% of mice receiving TcES developed tumors. Tumor numbers per mouse were significantly reduced in TcES-treated mice (4.5 tumors) versus untreated mice (14.5 tumors). Both inflammation and proliferation scores in the colon from CAC-TcES-treated mice were significantly lower than CAC-untreated mice. High levels of IL-1β, TNF-α, and IL-17 in CAC-untreated mice were down-modulated by TcES-treatment. Lower expression of COX2, β-catenin and, STAT3 activation were detected in colonic tissue from mice receiving TcES. Our data suggest a main role for TcES in generating an anti-inflammatory environment that suppresses CAC progression

Food-grade titanium dioxide exposure exacerbates tumor formation in colitis associated cancer model

Colorectal cancer is the fourth worldwide cause of death and even if some dietary habits are consider risk factors, the contribution of food additives including foodgrade titanium dioxide (TiO2), designated as E171, has been poorly investigated. We hypothesized that oral E171 intake could have impact on the enhancement of colorectal tumor formation and we aimed to investigate if E171 administration could enhance tumor formation in a colitis associated cancer (CAC) model. BALB/c male mice were grouped as follows: a) control, b) E171, c) CAC and d) CAC + E171 group (n = 6). E171 used in this study formed agglomerates of 300 nm in water. E171 intragastric administration (5 mg/kg body weight/5 days/10 weeks) was unable to induce tumor formation but dysplastic alterations were observed in the distal colon but enhanced the tumor formation in distal colon (CAC + E171 group) measured by tumor progression markers. Some E171 particles were internalized in colonic cells of the E171 and CAC + E171 groups and both groups showed a decrease in goblet cells in the distal colon. However the CAC + E171 group showed a higher decrease of these cells that act as protection barrier in colon. These results suggest that E171 could worsen pre-existent intestinal diseases.

Anti-inflammatory and Antitumor Activity of a Triple Therapy for a Colitis-Related Colorectal Cancer

Colorectal cancer (CRC) is an important health issue worldwide, accounting for the third place of cancer incidence. Chronic inflammation, as seen in Crohn's disease and ulcerative colitis, is the most important risk factor for developing CRC, as it favours neoplastic transformation by enhancing epithelial cell turnover in the colonic mucosa. Treatments for CRC need to be improved; currently they are not specific and have several secondary effects in patients. The main objective of this work was to evaluate a new therapeutic strategy against a colitis-related colorectal cancer in vivo and in vitro by targeting mTOR-signaling and lactate dehydrogenase A. Together, these mechanisms directly affect tumor energetics. In this study we evaluated a better and more efficient triple therapy against a chronic inflammation-associated CRC in vivo and in vitro. After the development of tumors, mice were treated intraperitoneally during a forty-day period with single drugs or different combinations of Metformin, Sodium Oxamate and Doxorubicin. Targeted inhibition of the mTOR pathway, lactate dehydrogenase A and the concurrent use of Doxorubicin (called in this work as triple therapy), leaded to a notable reduction in the number and size of tumors in mice, and, a significant pro-inflammatory cytokines reduction Besides, we showed that treated cells were induced to early autophagy, and apoptosis cell death. Our results represent a novel and robust therapeutic strategy for overcoming CRC by means of targeting central molecular pathways in cancer by the combination of Metformin, Oxamate, and Doxorubicin leading to a rapid tumor growth inhibition and a dramatic colorectal crypt restoration. Besides, drug combination resulted in a notable reduction of anti-inflammatory cytokines.

Extraintestinal helminth infection reduces the development of colitis-associated tumorigenesis

Colitis-associated colorectal cancer (CAC) is one of the most common cancers and is closely related to chronic or deregulated inflammation. Helminthic infections can modulate inflammatory responses in some diseases, but their immunomodulatory role during cancer development remains completely unknown. We have analyzed the role of Taenia crassiceps-induced anti-inflammatory response in determining the outcome of CAC. We show that extraintestinal T. crassiceps infection in CAC mice inhibited colonic inflammatory responses and tumor formation and prevented goblet cell loss. There was also increased expression of IL-4 and alternatively activated macrophages markers in colonic tissue and negative immunomodulation of pro-inflammatory cytokine expression. In addition, T. crassiceps infection prevented the upregulation of β-catenin and CXCR2 expression observed in the CAC mice, which are both markers associated with CAC-tumorigenesis, and reduced the numbers of circulating and colonic CD11b⁺Ly6C^hiCCR2⁺ monocytes. Thus, immunomodulatory activities induced by helminth infections may have a role in the progression of CAC.

Extraintestinal helminth infection reduces the development of colitis-associated colorectal cancer (MPF1P.763)

Whereas a causal association between viral and bacterial infections with tumor development has been well established in animal and epidemiological studies, the impact of parasitic infections in cancer development is almost unknown. Evidences indicate that cancer can be triggered by chronic or deregulated inflammatory processes, such as colitis-associated colorectal cancer (CAC). Using a helminth infection model, we have analyzed the role of helminth-induced anti-inflammatory response in determining the outcome of CAC. Following Taenia crassiceps infection and development of CAC, mice displayed inhibited colonic inflammatory responses and reduced circulating and colonic CD11b+Ly6C+CCR2+ monocytes. Instead they increased the expression of IL-4 and alternatively activated macrophages (AAMs) markers at the colonic tissue. Strikingly, T. crassiceps-infected mice developed few tumors and reduced pathology. In contrast, uninfected mice mounted strong inflammatory responses, did not express AAMs markers, developed severe pathology and displayed multiple tumors. Thus, immunomodulatory activities induced by helminth infections may have a role in the resistance and progression of CAC.

Macrophage migration inhibitory factor has a role in controlling colorectal cancer (TUM4P.918)

Chronic Inflammation has been related with cancer development by counteracting and unbalancing the immune response. The inflammatory cytokine macrophage migration inhibitory factor (MIF) is overexpressed in many carcinogenic tumors, stimulates angiogenesis and metastasis promoting proliferation and survival in malignant cells. In the inflammatory disease ulcerative colitis, MIF is early expressed and favors the inflammatory cytokine production like TNF-α and IL-1β. As intestinal chronic inflammation may proceed to colorectal cancer, we are interested in determining the role of MIF on development and pathology on colorectal cancer. To elucidate this point we used MIF-KO and WT mice, both with BALB/c genetic background, to develop a colorectal cancer model of Dextran Sodium Sulfate and Azoxymethan. As expected, MIF-KO mice showed low levels of serum inflammatory cytokines TNF-α, IL-1β and IFN-γ compare to WT mice. Strikingly, we found significantly more tumors and in a higher development stage on MIF-KO mice (24.4+/-2) compared to WT mice (12.6+/-2). Higer numbers of CD4+ cells were detected in intestinal epithelial cells on WT mice compared to MIF-KO mice. Therefore, although MIF has been recognized as a promoter of inflammation, which could favor the development of cancer, our results suggest that MIF is involved in controlling the development of colorectal cancer, possibly by its chemokine properties.

Th2-associated alternative Kupffer cell activation promotes liver fibrosis without inducing local inflammation

Cirrhosis is the final outcome of liver fibrosis. Kupffer cell-mediated hepatic inflammation is considered to aggravate liver injury and fibrosis. Alternatively-activated macrophages are able to control chronic inflammatory events and trigger wound healing processes. Nevertheless, the role of alternative Kupffer cell activation in liver harm is largely unclear. Thus, we evaluated the participation of alternatively-activated Kupffer cells during liver inflammation and fibrosis in the murine model of carbon tetrachloride-induced hepatic damage. To stimulate alternative activation in Kupffer cells, 20 Taenia crassiceps (Tc) larvae were inoculated into BALBc/AnN female mice. Six weeks post-inoculation, carbon tetrachloride or olive oil were orally administered to Tc-inoculated and non-inoculated mice twice per week during other six weeks. The initial exposure of animals to T. crassiceps resulted in high serum concentrations of IL-4 accompanied by a significant increase in the hepatic mRNA levels of Ym-1, with no alteration in iNOS expression. In response to carbon tetrachloride, recruitment of inflammatory cell populations into the hepatic parenchyma was 5-fold higher in non-inoculated animals than Tc-inoculated mice. In contrast, carbon tetrachloride-induced liver fibrosis was significantly less in non-inoculated animals than in the Tc-inoculated group. The latter showed elevated IL-4 serum levels and low IFN-γ concentrations during the whole experiment, associated with hepatic expression of IL-4, TGF-β, desmin and α-sma, as well as increased mRNA levels of Arg-1, Ym-1, FIZZ-1 and MMR in Kupffer cells. These results suggest that alternative Kupffer cell activation is favored in a Th2 microenvironment, whereby such liver resident macrophages could exhibit a dichotomic role during chronic hepatic damage, being involved in attenuation of the inflammatory response but at the same time exacerbation of liver fibrosis.

Standardization of an experimental model of human taeniosis for oral vaccination

Neurocysticercosis in humans is caused by the tapeworm Taenia solium and generates substantial morbidity in Latin America, Africa and Asia.The life cycle of T. solium includes pigs as intermediate hosts and human beings as definitive hosts. Tapeworm carriers are the main risk factor for acquiring cysticercosis in the household, thus prevention and control programs are being developed. Infected people have no symptoms, therefore are difficult to identify and treat, thus vaccination against the adult tapeworm is an alternative control measure. Since the infection occurs naturally only in human beings, experimental models have been standardized. Hamsters are believed to be good models to study the infection but they have not been properly evaluated for vaccination. Since taeniosis is gained by ingesting pork meat with cysticerci, oral vaccination was evaluated, and given that intestinal immunity is enhanced with adjuvants, cholera toxin was used, because it is one of the most potent adjuvants, in view of the fact that it increases epithelium permeability enhancing entrance of the co-administered unrelated antigens. Recombinant functional T. solium calreticulin was employed for the standardization of the methodology and the evaluation of oral vaccination. Protection was associated with the type of cysticerci and the age of the hamsters used. When reddish bigger parasites were orally introduced in hamsters as challenge, protection was around 40%, while when yellowish small parasites were used, protection increased to 100%, suggesting that the characteristics of cysticerci are determinant. Protection was gained in 9month old hamsters, but not in 3month old animals.