Immunotherapy synergizes with chemotherapy targeting pancreatic cancer

Antigen-loaded dendritic cells triggers a specific cytotoxic T lymphocytes immune response against hepatocellular carcinoma: in vitro study

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the common malignancies, characterized by poor response to conventional therapeutic options. Immunotherapy with dendritic cells (DCs)-vaccines is one of the most successful strategies used for the treatment of HCC. However, the methods applied in the preparation of antigen-loaded DCs are important factors for optimization of DCs vaccines.

PURPOSE

The present study was conducted to investigate the effect of HCC-whole tumor cell lysate prepared using rapid repetitive freeze-thaw cycles on the immunogenicity of DCs and evaluate the ability of whole tumor cell lysate-pulsed DCs vaccine to induce a specific cytotoxic T lymphocytes (CTLs) response against HepG2 cell line.

METHODS

Immature DCs generated from peripheral blood monocytes were randomized into two groups: control DCs and whole tumor cell lysate-pulsed DCs. Phenotypic analysis of the DCs' cell maturation marker CD83 and co-stimulatory molecule CD86 was performed. HCC-specific cytotoxic activity of CD8⁺ CTLs was measured in vitro.

RESULTS

Loading of DCs with necrotic whole cell lysate resulted in non-significant changes in DCs' expression of CD83, but a significant increase in expression of CD86. In addition, CD8⁺ CTLs stimulated with whole tumor cell lysate-pulsed DCs showed a high cytotoxic activity that specifically attack HepG2 cells.

CONCLUSION

Our findings indicated that pulsation of DCs with whole tumor cell lysate prepared by repetitive freeze-thaw cycles could efficiently enhance the ability of DCs to induce proliferation and clonal expansion of CD8⁺ CTLs. Data herein, also indicated that whole tumor cell lysate-pulsed DCs triggers a specific CD8⁺ CTLs against HCC tumor cells.

New frontiers in the treatment of colorectal cancer: Autophagy and the unfolded protein response as promising targets

Colorectal cancer (CRC), despite numerous therapeutic and screening attempts, still remains a major life-threatening malignancy. CRC etiology entails both genetic and environmental factors. Macroautophagy/autophagy and the unfolded protein response (UPR) are fundamental mechanisms involved in the regulation of cellular responses to environmental and genetic stresses. Both pathways are interconnected and regulate cellular responses to apoptotic stimuli. In this review, we address the epidemiology and risk factors of CRC, including genetic mutations leading to the occurrence of the disease. Next, we discuss mutations of genes related to autophagy and the UPR in CRC. Then, we discuss how autophagy and the UPR are involved in the regulation of CRC and how they associate with obesity and inflammatory responses in CRC. Finally, we provide perspectives for the modulation of autophagy and the UPR as new therapeutic options for CRC treatment.

Wilms’ tumor 1 (WT1)-targeted cancer vaccines to extend survival for patients with pancreatic cancer

Despite novel chemotherapy treatments, pancreatic ductal adenocarcinoma (PDA) remains a lethal disease. New targeted cancer vaccines may represent a viable option for patients with PDA. The Wilms’ tumor 1 (WT1) antigen is one of the most widely expressed tumor-associated antigens in various types of tumors, including PDA. Recent reports have indicated that WT1-targeted cancer vaccines for patients with PDA mediated a potent antitumor effect when combined with chemotherapy in preclinical and clinical studies. This review summarizes the early-phase clinical trials of WT1-targeted cancer vaccines (peptide vaccines and dendritic cell-based vaccines) for PDA. Moreover, we will discuss future strategies for PDA treatments using WT1-specific cancer vaccines combined with immune checkpoint therapies to maximize the clinical effectiveness of PDA treatments.

Advances in inducing adaptive immunity using cell-based cancer vaccines: Clinical applications in pancreatic cancer

The incidence of pancreatic ductal adenocarcinoma (PDA) is on the rise, and the prognosis is extremely poor because PDA is highly aggressive and notoriously difficult to treat. Although gemcitabine- or 5-fluorouracil-based chemotherapy is typically offered as a standard of care, most patients do not survive longer than 1 year. Therefore, the development of alternative therapeutic approaches for patients with PDA is imperative. As PDA cells express numerous tumor-associated antigens that are suitable vaccine targets, one promising treatment approach is cancer vaccines. During the last few decades, cell-based cancer vaccines have offered encouraging results in preclinical studies. Cell-based cancer vaccines are mainly generated by presenting whole tumor cells or dendritic cells to cells of the immune system. In particular, several clinical trials have explored cell-based cancer vaccines as a promising therapeutic approach for patients with PDA. Moreover, chemotherapy and cancer vaccines can synergize to result in increased efficacies in patients with PDA. In this review, we will discuss both the effect of cell-based cancer vaccines and advances in terms of future strategies of cancer vaccines for the treatment of PDA patients.

Dendritic cell-based cancer immunotherapy for colorectal cancer

Colorectal cancer (CRC) is one of the most common cancers and a leading cause of cancer-related mortality worldwide. Although systemic therapy is the standard care for patients with recurrent or metastatic CRC, the prognosis is extremely poor. The optimal sequence of therapy remains unknown. Therefore, alternative strategies, such as immunotherapy, are needed for patients with advanced CRC. This review summarizes evidence from dendritic cell-based cancer immunotherapy strategies that are currently in clinical trials. In addition, we discuss the possibility of antitumor immune responses through immunoinhibitory PD-1/PD-L1 pathway blockade in CRC patients.

Immunotherapy for colorectal cancer

The incidence of colorectal cancer (CRC) is on the rise, and the prognosis for patients with recurrent or metastatic disease is extremely poor. Although chemotherapy and radiation therapy can improve survival rates, it is imperative to integrate alternative strategies such as immunotherapy to improve outcomes for patients with advanced CRC. In this review, we will discuss the effect of immunotherapy for inducing cytotoxic T lymphocytes and the major immunotherapeutic approaches for CRC that are currently in clinical trials, including peptide vaccines, dendritic cell-based cancer vaccines, whole tumor cell vaccines, viral vector-based cancer vaccines, adoptive cell transfer therapy, antibody-based cancer immunotherapy, and cytokine therapy. The possibility of combination therapies will also be discussed along with the challenges presented by tumor escape mechanisms.

Combination treatment with comprehensive cryoablation and immunotherapy in metastatic pancreatic cancer

OBJECTIVE

The aim of this study was to retrospectively assess the effect of comprehensive cryosurgery (ablation of intrapancreatic and extrapancreatic tumors) plus immunotherapy in metastatic pancreatic cancer.

METHODS

We divided 106 patients (57 men, 49 women; median age, 65 years) into the cryoimmunotherapy (31 patients), cryotherapy (36 patients), immunotherapy (17 patients), and chemotherapy groups (22 patients). Pretreatment immune function was tested in patients who underwent immunotherapy. Overall survival (OS) after diagnosis of metastatic pancreatic cancer was assessed after a 4-year follow-up.

RESULTS

Median OS was higher in the cryoimmunotherapy (13 months) and cryotherapy groups (7 months) than in the chemotherapy group (3.5 months; both P < 0.001) and was higher in the cryoimmunotherapy group than in the cryotherapy (P < 0.05) and immunotherapy groups (5 months; P < 0.001). In both the cryoimmunotherapy and cryotherapy groups, median OS was higher after multiple cryoablations than after a single cryoablation (P = 0.0048 and 0.041, respectively). In both groups, the median OS was higher in patients with normal immunologic function than in those with immune dysfunction (P < 0.0001 and P = 0.0004, respectively).

CONCLUSIONS

Cryoimmunotherapy significantly increased OS in metastatic pancreatic cancer. Multiple cryoablations and normal pretreatment immunologic function were associated with better prognosis.

A randomized pilot phase I study of modified carcinoembryonic antigen (CEA) peptide (CAP1-6D)/montanide/GM-CSF-vaccine in patients with pancreatic adenocarcinoma

Background

CEA is expressed in >90% of pancreatic cancers (PC) and may be an appropriate immunotherapy target. CEA is poorly immunogenic due to immune tolerance; CAP1-6D, an altered peptide ligand can help bypass tolerance. We conducted a pilot randomized phase I trial in PC patients to determine the peptide dose required to induce an optimal CD8⁺ T cell response.

Methods

Patients with a PS 0-1, HLA-A2+ and CEA-expressing, previously-treated PC were randomized to receive 10 μg (arm A), 100 μg (arm B) or 1000 μg (arm C) of CEA peptide emulsified in Montanide and GM-CSF, given every 2 weeks until disease progression.

Results

Sixty-six patients were screened and 19 enrolled of whom 14 received at least 3 doses of the vaccine and thus evaluated for the primary immunologic endpoint. A median of 4 cycles (range 1-81) was delivered. Median and mean peak IFN-γ T cell response by ELISPOT (spots per 10⁴ CD8⁺ cells, Arm A/B/C) was 11/52/271 (A vs. C, p = 0.028) for medians and 37/148/248 (A vs. C, p = 0.032) for means. T cell responses developed or increased in 20%/60%/100% of pts in Arms A/B/C. Seven of the 19 patients remain alive at a minimum 32 months from trial initiation, including three with unresectable disease.

Conclusions

The T cell response in this randomized phase I trial was dose-dependent with the 1 mg CEA peptide dose eliciting the most robust T cell responses. A signal of clinical benefit was observed and no significant toxicity was noted. Further evaluation of 1 mg CEA peptide with stronger adjuvants, and/or combined with agents to overcome immune inhibitory pathways, may be warranted in PC pts.

Trial registration

ClinicalTrials.gov NCT00203892

The combination of TLR2 and TLR4 agonists promotes the immunogenicity of dendritic cell/cancer cell fusions

The induction of antitumor immune responses by dendritic cell (DC)/tumor cell fusions can be modulated by their activation status. Our recent work reveals that the combination of Toll-like receptor 2 (TLR2) and TLR4 agonists promotes the immunogenicity of DC/tumor cell fusions, allowing them to overcome the immunosuppressive effects of transforming growth factor β1.