Induction of Th1Immune responses following laser ablation in a murine model of colorectal liver metastases

<p>Abstract</p> <p>Background</p> <p>Preliminary experimental studies have suggested that the in situ destruction of tumor tissue by local laser ablation (LA) may also stimulate host immunity against cancer. We investigated local and systemic induction of immune responses after laser ablation in the setting of residual tumor.</p> <p>Methods</p> <p>A murine colorectal cancer (CRC) liver metastasis model was used. Selected tumors of liver CRC bearing mice and livers of mice without tumor induction were treated with LA. Liver and tumor tissues from the ablation sites and from distant sites were collected at various time points following LA and changes in CD3+ T cells and Kupffer cells (F4/80 marker) infiltration and the expression of interferon gamma (IFNγ) were investigated by immunohistochemistry and ELISpot. Base line levels of CD3+ T cells and Kupffer cells were established in untreated mice.</p> <p>Results</p> <p>The presence of tumor induced significant accumulation of CD3+ T cells and Kupffer cells at the tumor-host interface, within the tumor vascular lakes and increased their baseline concentration within the liver parenchyma. LA of the <it>liver </it>induced accumulation of CD3+ T-cells and Kupffer cells at the site of injury and systemic induction of immune responses as discerned by the presence of IFNγ secreting splenocytes. LA of liver <it>tumors </it>induced significant increase of CD3+ T-cells at site of injury, within normal liver parenchyma, and the tumor-host interface of both ablated and distant tumors. In contrast Kupffer cells only accumulated in ablated tumors and the liver parenchyma but not in distant tumors. IFNγ expression increased significantly in ablated tumors and showed an increasing trend in distant tumors.</p> <p>Conclusion</p> <p>Laser ablation in addition to local tumor destruction induces local and systemic Th1 type immune responses which may play a significant role in inhibiting tumor recurrence from residual micrometastases or circulating tumor cells.</p

The hepatitis B virus pre-core protein p22 activates Wnt sgnaling

An emerging theme for Wnt-addicted cancers is that the pathway is regulated at multiple steps via various mechanisms. Infection with hepatitis B virus (HBV) is a major risk factor for liver cancer, as is deregulated Wnt signaling, however, the interaction between these two causes is poorly understood. To investigate this interaction, we screened the effect of the various HBV proteins for their effect on Wnt/β-catenin signaling and identified the pre-core protein p22 as a novel and potent activator of TCF/β-catenin transcription. The effect of p22 on TCF/β-catenin transcription was dose dependent and inhibited by dominant-negative TCF4. HBV p22 activated synthetic and native Wnt target gene promoter reporters, and TCF/β-catenin target gene expression in vivo. Importantly, HBV p22 activated Wnt signaling on its own and in addition to Wnt or β-catenin induced Wnt signaling. Furthermore, HBV p22 elevated TCF/β-catenin transcription above constitutive activation in colon cancer cells due to mutations in downstream genes of the Wnt pathway, namely APC and CTNNB1. Collectively, our data identifies a previously unappreciated role for the HBV pre-core protein p22 in elevating Wnt signaling. Understanding the molecular mechanisms of p22 activity will provide insight into how Wnt signaling is fine-tuned in cancer

Advances in targeted and immunobased therapies for colorectal cancer in the genomic era

Targeted therapies require information on specific defective signaling pathways or mutations. Advances in genomic technologies and cell biology have led to identification of new therapeutic targets associated with signal-transduction pathways. Survival times of patients with colorectal cancer (CRC) can be extended with combinations of conventional cytotoxic agents and targeted therapies. Targeting EGFR- and VEGFR-signaling systems has been the major focus for treatment of metastatic CRC. However, there are still limitations in their clinical application, and new and better drug combinations are needed. This review provides information on EGFR and VEGF inhibitors, new therapeutic agents in the pipeline targeting EGFR and VEGFR pathways, and those targeting other signal-transduction pathways, such as MET, IGF1R, MEK, PI3K, Wnt, Notch, Hedgehog, and death-receptor signaling pathways for treatment of metastatic CRC. Additionally, multitargeted approaches in combination therapies targeting negative-feedback loops, compensatory networks, and cross talk between pathways are highlighted. Then, immunobased strategies to enhance antitumor immunity using specific monoclonal antibodies, such as the immune-checkpoint inhibitors anti-CTLA4 and anti-PD1, as well as the challenges that need to be overcome for increased efficacy of targeted therapies, including drug resistance, predictive markers of response, tumor subtypes, and cancer stem cells, are covered. The review concludes with a brief insight into the applications of next-generation sequencing, expression profiling for tumor subtyping, and the exciting progress made in in silico predictive analysis in the development of a prescription strategy for cancer therapy

Additional file 2: of Vascular disruptive agent OXi4503 and anti-angiogenic agent Sunitinib combination treatment prolong survival of mice with CRC liver metastasis

OXi4503, Sunitinib and combination treatments induce EMT in the surviving tumor cells. Formalin-fixed control and treated tumor sections were stained with antibodies to E-cadherin, ZEB1, or Vimentin. Positive expression is detected by the brown staining. Scale bar = 200 mm. L = liver, T = live tumor. NT = necrotic tumor. Images are representative for each treatment group (n ≥ 5 animals). (PDF 417 kb

Dendritic Cells Induce Immunity and Long-Lasting Protection against Blood-Stage Malaria despite an In Vitro Parasite-Induced Maturation Defect

Dendritic cells (DC) suffer a maturation defect following interaction with erythrocytes infected with malaria parasites and become unable to induce protective malaria liver-stage immunity. Here we show that, by contrast, maturation-arrested DC in vitro are capable of the successful induction of antigen-specific gamma interferon (IFN-γ) and interleukin 4 (IL-4) T-cell responses, antibody responses, and potent protection against lethal blood-stage malaria challenge in vivo. Similar results were found with DC pulsed with intact parasitized Plasmodium yoelii or Plasmodium chabaudi erythrocytes. Cross-strain protection was also induced. High levels of protection (80 to 100%) against lethal challenge were evident from 10 days after a single immunization and maintained up to 120 days. Interestingly, correlation studies versus blood-stage protection at different time points suggest that the immune effector mechanisms associated with protection could change over time. Antibody-independent, T-cell- and IL-12-associated protection was observed early after immunization, followed by antibody and IL-4-associated, IFN-γ-independent protection in long-term studies. These results indicate that DC, even when clearly susceptible to parasite-induced maturation defect effects in vitro, can be central to the induction of protection against blood-stage malaria in vivo

SAR131675, a VEGRF3 Inhibitor, Modulates the Immune Response and Reduces the Growth of Colorectal Cancer Liver Metastasis

Most patients with colorectal cancer (CRC) develop metastases, predominantly in the liver (CLM). Targeted therapies are being investigated to improve current CLM treatments. This study tested the effectiveness of SAR131675, a selective VEGFR-3 tyrosine kinase inhibitor, to inhibit CLM in a murine model. Following intrasplenic induction of CLM, mice were treated daily with SAR131675. Tumor growth and immune infiltrates into tumor and liver tissues were assessed at 10-, 16- and 22-days post tumor induction by stereology, IHC and flow cytometry. SAR151675 treatment significantly reduced tumor burden and F4/80+ macrophages in the liver tissues. Analysis of immune cell infiltrates in liver showed tissue that at day 22, had the proportion of CD45+ leukocytes significantly reduced, particularly myeloid cells. Analysis of myeloid cells (CD11b+ CD45+) indicated that the proportion of F4/80− Ly6Clow was significantly reduced, including a predominate PD-L1+ subset, while CD3+ T cells increased, particularly CD8+ PD1+, reflected by an increase in the CD8+:CD4+ T cell ratio. In the tumor tissue SAR11675 treatment reduced the predominant population of F4/80+ Ly6Clo and increased CD4+ T cells. These results suggest that SAR131675 alters the immune composition within tumor and the surrounding liver in the later stages of development, resulting in a less immunosuppressive environment. This immunomodulation effect may contribute to the suppression of tumor growth

Treatment with the vascular disruptive agent OXi4503 induces an immediate and widespread epithelial to mesenchymal transition in the surviving tumor

Epithelial to mesenchymal transition (EMT) is considered an important mechanism in tumor resistance to drug treatments; however, in vivo observation of this process has been limited. In this study we demonstrated an immediate and widespread EMT involving all surviving tumor cells following treatment of a mouse model of colorectal liver metastases with the vascular disruptive agent OXi4503. EMT was characterized by significant downregulation of E-cadherin, relocation and nuclear accumulation of b-catenin as well as significant upregulation of ZEB1 and vimentin. Concomitantly, significant temporal upregulation in hypoxia and the pro-angiogenic growth factors hypoxia-inducible factor 1-alpha, hepatocyte growth factor, vascular endothelial growth factor and transforming growth factor-beta were seen within the surviving tumor. The process of EMT was transient and by 5 days after treatment tumor cell reversion to epithelial morphology was evident. This reversal, termed mesenchymal to epithelial transition (MET) is a process implicated in the development of new metastases but has not been observed in vivo histologically. Similar EMT changes were observed in response to other antitumor treatments including chemotherapy, thermal ablation, and antiangiogenic treatments in our mouse colorectal metastasis model and in a murine orthotopic breast cancer model after OXi4503 treatment. These results suggest that EMT may be an early mechanism adopted by tumors in response to injury and hypoxic stress, such that inhibition of EMT in combination with other therapies could play a significant role in future cancer therapy

Renin–Angiotensin Inhibitor, Captopril, Attenuates Growth of Patient-Derived Colorectal Liver Metastasis Organoids

The recurrence of colorectal liver metastasis (CRLM) following liver resection is common; approximately 40% of patients will experience tumor recurrence post-surgery. Renin–angiotensin inhibitors (RASis) have been shown to attenuate the growth and progression of CRLM in pre-clinical models following liver resection. This study examined the efficacy of the RASi captopril on patient-derived colorectal liver metastasis organoids. Patient-derived organoids (PDOs) were established using fresh samples of colorectal liver metastasis from appropriately consented patients undergoing liver resection. To mimic the regenerating liver post-CRLM liver resection, PDOs were cultured under hepatocyte regeneration conditions in vitro. CRLM PDOs were established from three patients’ parent tissue. CRLM PDOs and parent tissue expressed markers of colorectal cancer, CDX2 and CK20, consistently. Furthermore, CRLM PDOs treated with captopril showed a dose dependent reduction in their expansion in vitro. In conclusion, CRLM PDOs recapitulate in vivo disease and displayed a dose-dependent response to treatment with captopril. RASis may be an additional viable treatment for patients with CRLM