Vaccination with in vitro grown whole tumor cells induces strong immune responses and retards tumor growth in a murine model of colorectal liver metastases

Multiple Protein Biomarkers and Different Treatment Strategies for Colorectal Carcinoma: A Comprehensive Prospective

In this review, we emphasized important biomarkers, pathogenesis, and newly developed therapeutic approaches in the treatment of colorectal cancer (CRC). This includes a complete description of small-molecule inhibitors, phytopharmaceuticals with antiproliferative potential, monoclonal antibodies for targeted therapy, vaccinations as immunotherapeutic agents, and many innovative strategies to intervene in the interaction of oncogenic proteins. Many factors combine to determine the clinical behavior of colorectal cancer and it is still difficult to comprehend the molecular causes of a person's vulnerability to CRC. It is also challenging to identify the causes of the tumor's onset, progression, and responsiveness or resistance to antitumor treatment. Current recommendations for targeted medications are being updated by guidelines throughout the world in light of the growing number of high-quality clinical studies. So, being concerned about the aforementioned aspects, we have tried to present a summarized pathogenic view, including a brief description of biomarkers and an update of compounds with their underlying mechanisms that are currently under various stages of clinical testing. This will help to identify gaps or shortfalls that can be addressed in upcoming colorectal cancer research.

Immunotherapy for Colorectal Cancer: Mechanisms and Predictive Biomarkers

Simple Summary

Late-stage colorectal cancer treatment often involves chemotherapy and radiation that can cause dose-limiting toxicity, and therefore there is great interest in developing targeted therapies for this disease. Immunotherapy is a targeted therapy that uses peptides, cells, antibodies, viruses, or small molecules to engage or train the immune system to kill cancer. Here, we discuss the preclinical and clinical development of immunotherapy for treatment of colorectal cancer and provide an overview of predictive biomarkers for such treatments. We also consider open questions including optimal combination treatments and sensitization of colorectal cancer patients with proficient mismatch repair enzymes.

Abstract

Though early-stage colorectal cancer has a high 5 year survival rate of 65–92% depending on the specific stage, this probability drops to 13% after the cancer metastasizes. Frontline treatments for colorectal cancer such as chemotherapy and radiation often produce dose-limiting toxicities in patients and acquired resistance in cancer cells. Additional targeted treatments are needed to improve patient outcomes and quality of life. Immunotherapy involves treatment with peptides, cells, antibodies, viruses, or small molecules to engage or train the immune system to kill cancer cells. Preclinical and clinical investigations of immunotherapy for treatment of colorectal cancer including immune checkpoint blockade, adoptive cell therapy, monoclonal antibodies, oncolytic viruses, anti-cancer vaccines, and immune system modulators have been promising, but demonstrate limitations for patients with proficient mismatch repair enzymes. In this review, we discuss preclinical and clinical studies investigating immunotherapy for treatment of colorectal cancer and predictive biomarkers for response to these treatments. We also consider open questions including optimal combination treatments to maximize efficacy, minimize toxicity, and prevent acquired resistance and approaches to sensitize mismatch repair-proficient patients to immunotherapy.

"First do no harm" and the importance of prediction in oncology

Present cancer treatment strategies are based on the assumption that a therapy may work (“response”) or not work (“no-response”). However, the existing evidence suggests that current cancer treatment modalities may also have a cancer-promoting effect in part of the patients. In this paper, some relevant data are reviewed suggesting that surgery, irradiation, chemotherapy and immunotherapy can stimulate tumor growth / metastatic spread and decrease survival of patients in certain subgroups. Thus, results of cancer treatment may be improved by detection and use of biomarkers that correlate with positive or negative therapeutic effects. Small trials based on groups with differing biomarkers rather than large phase III trials may aid the development and efficacy testing of new anticancer drugs. Moreover, ignoring biomarkers that correlate with positive or negative therapeutic effect may not be compatible anymore with the ethical principle “First Do No Harm”.

Dendritic cell/tumor hybrids enhances therapeutic efficacy against colorectal cancer liver metastasis in SCID mice

OBJECTIVE

Colorectal cancer (CRC) is one of the most common malignancies in the western world. More than 60% among patients will develop liver metastases. Although surgical resection is the first choice worldwide, at this point an effective approach for the treatment of patients with liver metastasis and cancer recurrence postoperation has not yet been found. The aim of this study is to investigate the role of the allogeneic dendritomas from fusion of DCs and metastatic colon cancer cells in the activation of anti-tumor immunity against colorectal cancer liver metastases.

MATERIAL AND METHODS

Hybrids were generated by fused allogeneic human peripheral blood dendritic cells with metastatic colon cancer SW620 cells using 50% polyethylene glycol (PEG). Induction of immune responses was assessed by ex vivo ELISPOT assays. A murine model of CRC liver metastasis was used by intrasplenic injection. The validity of the vaccine was observed by Vaccination CRC liver metastasis murine model with DC/tumor hybrids.

RESULTS

The hybrids highly express the major molecules of DCs and tumor cells. The number of hybrids pulsed CTL secreting IFN-gamma was significantly higher when compared to the DC controls (p < 0.01). In a therapeutic setting mice vaccinated with in vitro cultured hybrids produced strong cellular immune responses and significant inhibition of tumor growth, compared to sham vaccinated controls.

CONCLUSIONS

Vaccination with hybrids can induces strong cellular responses and significant protection from challenge in SCID mouse metastatic CRC model.