Immunotherapy for metastatic colorectal cancer: present status and new options

Berries vs. Disease: Revenge of the Phytochemicals

Secondary metabolites and phytochemicals in plant-based diets are known to possess properties that inhibit the development of several diseases including a variety of cancers of the aerodigestive tract. Berries are currently of high interest to researchers due to their high dietary source of phytochemicals. Black raspberries (BRB), Rubus occidentalis, are of special interest due to their rich and diverse composition of phytochemicals. In this review, we present the most up-to-date preclinical and clinical data involving berries and their phytochemicals in the chemoprevention of a variety of cancers and diseases. BRBs possess a variety of health benefits including anti-proliferative properties, anti-inflammatory activity, activation of pro-cell-death pathways, modulation of the immune response, microbiome modulation, reduction in oxidative stress, and many more. However, little has been done in both preclinical and clinical settings on the effects of BRB administration in combination with other cancer therapies currently available for patients. With the high potential for BRBs as chemopreventive agents, there is a need to investigate their potential in combination with other treatments to improve therapeutic efficacy.

Ganoderma Lucidum Polysaccharides Enhance the Abscopal Effect of Photothermal Therapy in Hepatoma-Bearing Mice Through Immunomodulatory, Anti-Proliferative, Pro-Apoptotic and Anti-Angiogenic

Hepatocellular carcinoma is a malignant tumor with high morbidity and mortality, a highly effective treatment with low side effects and tolerance is needed. Photothermal immunotherapy is a promising treatment combining photothermal therapy (PTT) and immunotherapy. PTT induces the release of tumor-associated antigens by ablating tumor and Ganoderma lucidum polysaccharides (GLP) enhance the antitumor immunity. Results showed that Indocyanine Green (ICG) was successfully encapsulated into SF-Gel. ICG could convert light to heat and SF-Gel accelerates the photothermal effect in vitro and in vivo. PTT based on ICG/ICG-SF-Gel inhibited the growth of primary and distal tumors, GLP enhanced the inhibitory efficacy. ICG/ICG-SF-Gel-based PTT and GLP immunotherapy improved the survival time. ICG/ICG-SF-Gel-based PTT induces tumor necrosis and GLP enhanced the photothermal efficacy. ICG/ICG-SF-Gel-based PTT inhibited cell proliferation and angiogenesis, induced cell apoptosis, enhanced cellular immunity, and GLP enhanced these effects. In conclusion, GLP could enhance the abscopal effect of PTT in Hepatoma-bearing mice.

Chemotherapy combined with dendritic cell vaccine and cytokine-induced killer cells in the treatment of colorectal carcinoma: a meta-analysis

Aim

To investigate the efficacy and safety of dendritic cell (DC) vaccine combined with cytokine-induced killer (CIK) cell therapy in colorectal carcinoma (CRC).

Patients and methods

PubMed, Embase, and Cochrane Library databases were searched systematically for clinical trials of DC vaccine and CIK cell therapy combined with chemotherapy for CRC. The primary and secondary endpoints were overall survival (OS) and disease-free survival (DFS), respectively. Pooled risk ratios were used to assess the treatment efficacy. Both random and fixed effects models were used for statistical analysis. The study population consisted of 871 CRC patients enrolled in four trials.

Results

OS and DFS were significantly improved in patients who received chemotherapy combined with DC vaccine and CIK cells, and no severe adverse events were shown.

Conclusions

The study demonstrated that the addition of DC vaccine and CIK cell therapy to chemotherapy is feasible and effective in patients with CRC.

The Chinese Herbal Mixture Tien-Hsien Liquid Augments the Anticancer Immunity in Tumor Cell-Vaccinated Mice

BACKGROUND

The Chinese herbal mixture, Tien-Hsien liquid (THL), has been used as an anticancer dietary supplement for more than 20 years. Our previous studies have shown that THL can modulate immune responseand inhibit tumor growth. In this study, we further evaluated the effect of THL on anticancer immune response in mice vaccinated with γ-ray-irradiated tumor cells.

METHODS

The antitumor effect of THL was determined in mice vaccinated with low-tumorigenic CT-26-low colon cancer cells or γ-ray-irradiated high-tumorigenic CT-26-high colon cancer cells. The number of natural killer (NK) cells and T lymphocytes in the spleen was analyzed by flow cytometry. The tumor-killing activities of NK cells and cytotoxic T lymphocytes (CTLs) were analyzed by flow cytometry using YAC-1 and CT-26-high cells, respectively, as target cells. The levels of IFN-γ, IL-2, and TNF-α were determined by ELISA.

RESULTS

THL suppressed the growth of CT-26-high tumor in mice previously vaccinated with low-tumorigenic CT-26-low cells or γ-irradiated CT-26-high cells. THL increased the populations of NK cells and CD4+ T lymphocytes in the spleen and enhanced the tumor-killing activities of NK cells and CTL in mice vaccinated with γ-irradiated CT-26-high cells. THL increased the production of IFN-γ, IL-2, and TNF-α in mice vaccinated with γ-irradiated CT-26-high cells.

CONCLUSION

THL can enhance the antitumor immune responses in mice vaccinated with killed tumor cells. These results suggest that THL may be used as a complementary medicine for cancer patients previously treated with killed tumor cell vaccines, radiotherapy, or chemotherapy.

Black raspberries in cancer clinical trials: Past, present and future

BACKGROUND

Black raspberries (BRB) inhibit a broad range of cancers in preclinical models, including in vivo models of oral, esophageal, colon, breast and skin cancer. Promising preclinical results have led to clinical evaluations in cancer patients or patients at increased risk for cancer development.

OBJECTIVE

To summarize clinical investigations targeting cancer or precancerous lesions with BRB and discuss future directions.

METHODS

A thorough literature search was conducted through December 1, 2015 to identify all published studies evaluating BRB in cancer focused clinical trials.

RESULTS

Research investigating BRB in clinical settings report positive effects on preneoplastic lesions or cancers of the oral cavity, esophagus and colon. BRB treatment resulted in: histologic regression of oral intraepithelial neoplasia associated with improved histologic grade and significantly reduced loss of heterozygosity at tumor suppressor gene loci, modulated genes linked to RNA processing and growth factor recycling; in the colon, BRB inhibited FAP-associated polyp progression, demethylated tumor suppressor genes and improved plasma cytokine profiles; in Barrett's patients, BRB consumption increased tissue levels of GST-pi and decreased 8-isoprostane, a marker of lipid peroxidation/oxidative stress.

CONCLUSIONS

The precise dose, duration and optimum mode of BRB delivery for cancer inhibition remains to be fully elucidated. Common themes across studies support that BRB are anti-proliferative, anti- inflammatory, reduce oxidative stress and restore tumor suppressive activity. Future directions are included in the conclusions section.

Pi (Spleen)-deficiency syndrome in tumor microenvironment is the pivotal pathogenesis of colorectal cancer immune escape

Cancer immunoediting consists of three sequential phases: elimination, equilibrium, and escape. For colorectal adenoma-carcinoma sequence, the adenoma dysplastic progression may represent an equilibrium phase and the cancer stage as escape phase. Immune system eliminates transformed enterocytes by destroying them at first, sculpts them at the same time and selects the variants subsequently that are no longer recognized and insensitive to immune effectors, and finally induces immunosuppressive state within the tumor microenvironment that facilitates immune escape and tumor outgrowth. Immunosuppression and inflammation are the two crucial features of Pi (Spleen)-deficiency. Classic quotations, immune evidence and clinical observations suggest that Spleen (but not other organs) deficiency is the key pathogenesis of colorectal cancer (CRC) microenvironment. Weakness of old age, immunosuppressive cytokines from chronic inflammation, tumor-derived immunosuppressive factors and surrendered immune cells-regulatory T cells, myeloid-derived suppressor cells and tumor associated macrophages (TAMs) constitutes CRC microenvironment of Pi-deficiency. Furthermore, excess in superficiality, such as phlegm stagnation, blood stasis and toxin accumulation are induced by chronic inflammation on the basis of asthenia in origin, an immunosuppressive state. Great masters of Chinese medicine emphasize that strengthen Pi is the chief therapeutic principle for CRC which receives good therapeutic effects. So, Pi-deficiency based syndrome is the pivotal pathogenesis of tumor microenvironment. The immunosuppressive microenvironment facilitates immune escape which play an important role in the transition from adenoma to adenocarcinoma. There are some signs that strengthen Pi based treatment has potential capacity to ameliorate tumor environment. It might be a novel starting point to explore the mechanism of strengthen Pi based therapy in the prevention and treatment of CRC through regulation of tumor environment and immunoediting.

Validity of combination active specific immunotherapy for colorectal cancer: a meta-analysis of 2993 patients

BACKGROUND AIMS

The aim of this study was to investigate whether active specific immunotherapy (ASI) is able to demonstrate therapeutic efficacy against colorectal cancer.

METHODS

We conducted a systematic review of published papers from MEDLINE, the Cochrane Central Register of Controlled Trials, EMBASE, the Wanfang Database, the China Science and Technology Periodical Database and China Journal Net. Published data were extracted independently by two authors who used predefined database templates. The effects of ASI were compared with those of surgery alone, and a pooled analysis was performed with the use of the data from random- or fixed-effect models.

RESULTS

Twelve trials matched our inclusion criteria (n = 2993, including 1842 control subjects). The overall analysis showed a significant survival benefit [1-, 2-, 3-, 4-, 5-, 6- and 7-year overall survival (OS), P < 0.05; 10-year OS, P < 0.001] in favor of ASI immunotherapy combined with surgery, but there was not an improvement in the 8- or 9-year OS (P > 0.05). The disease-free survival (DFS) rate was improved after the combination of ASI immunotherapy (2-, 3-, 5- and 10-year DFS, P < 0.05), but no significant improvement was noted for the 1-, 4-, 6-, 7-, 8- or 9-year DFS (P > 0.05). In addition, the disease-specific survival (DSS) was improved at some time points after the combination of ASI immunotherapy and surgery (2-, 3-, 4-, 5- and 6-year DSS, P < 0.05, but not the 1-, 7-, 8- or 9-year DSS, P > 0.05). An improved 2-, 3-, 4-, 5- and 6-year recurrence-free interval (RFI) (P < 0.05) was also observed in patients who received ASI therapy, but this was not observed for the 1-year RFI (P > 0.05). Furthermore, an analysis of the recurrence-free survival (RFS) showed that it was significantly increased in the ASI plus surgery group (1-, 2-, 3-, 4-, 5- and 6-year RFS, P < 0.001). The funnel plots showed that the analyses were relatively reliable and the publication bias was small.

CONCLUSIONS

The combination of ASI immunotherapy and surgery was superior in prolonging the overall survival time and enhancing the recurrence-free survival rate compared with surgery alone.

Immunobiology and signaling pathways of cancer stem cells: implication for cancer therapy

Cancer stem cells (CSCs) need to survive cancer treatments with a specific end goal to provide new, more differentiated, metastatic-prone cancerous cells. This happens through diverse signals delivered within the tumor microenvironment where ample evidence indicates that altered developmental signaling pathways play an essential role in maintaining CSCs and accordingly the survival and the progression of the tumor itself. This review summarizes findings on the immunobiological properties of CSCs as compared with cancerous non-stem cells involving the expression of immunological molecules, cytokines and tumor antigens as well as the roles of the Notch, Wnt and Hedgehog pathways in the brain, breast and colon CSCs. We concluded that if CSCs are the main driving force behind tumor support and growth then understanding the molecular mechanisms and the immunological properties directing these cells for immune tolerance is of great clinical significance. Such knowledge will contribute to designing better targeted therapies that could prevent tumor recurrence and accordingly significantly improve cancer treatments and patient survival.

Designing effective vaccines for colorectal cancer

Achieving long-term control of colorectal cancers with therapeutic vaccines that generate potent anti-tumor T cell and antibody responses has been a goal for more than two decades. To date, clinical trials of these vaccines have demonstrated induction of immune responses, but clinical benefit has been limited. Improved vector delivery systems with enhanced immunostimulatory properties, decreased immunogenicity against vector and improved antigen presentation are some of the key features of modern tumor vaccines. Furthermore, an improved understanding of the various immunosuppressive factors in the tumor microenvironment and regional lymph nodes, coupled with a burgeoning ability to impair inhibitory immune synapses, highlights a growing opportunity to induce beneficial antigen-specific responses against tumor. The combination of improved antigenic delivery systems, coupled with therapeutic immune activation, represents state-of-the-art colorectal vaccine design concepts with the goal of augmenting immune responses against tumor and improving clinical outcomes.

Immune response, safety, and survival and quality of life outcomes for advanced colorectal cancer patients treated with dendritic cell vaccine and cytokine-induced killer cell therapy

Purpose. To determine the immune response after dendritic cell (DC) vaccine and cytokine-induced killer cells (CIK) therapy and assess its associated toxicity, survival benefit, and changes in the quality of life (QOL) of advanced colorectal cancer (CRC) patients. Methods. We recruited 100 patients with unresectable CRC orrelapsed CRC after surgery who received DC vaccine and CIK cells (group immunotherapy, group I), and, as a control, 251 patients who had similar characteristics and underwent similar treatments, except for this immunotherapy (group nonimmunotherapy, group NI). After a follow-up period of 489.2 ± 160.4 days, overall survival (OS) of the two groups was compared using the Kaplan-Meier method. Results. In group I, 62% of patients developed a positive delayed type hypersensitivity response, and most patients showed an improvement in physical strength (75.2%), appetite (74.2%), sleeping (72.1%), and body weight (70.1%). Adverse events were fever (29.5%), insomnia (19.2%), anorexia (9.1%), sore joints (5.4%), and skin rash (1.0%). No toxicity was observed in patients treated with DC vaccine and CIK therapy. OS was significantly longer in group I than in group NI (P = 0.043). Conclusion. DC vaccine and CIK therapy were safe and could induce an immune response against CRC, thereby improving QOL and prolonging OS.

Combination of chemotherapy and immunotherapy for colon cancer in China: A meta-analysis

AIM: To investigate whether autologous dendritic cell (DC)-cytokine-induced killer (CIK) cell therapy is able to improve the therapeutic efficacy of chemotherapy in colon cancer.

METHODS: We conducted a systematic review of published papers from the sources of MEDLINE, the Cochrane Central Register of Controlled Trials, EMBASE, the Wanfang Database, the China Science and Technology Periodical Database and China Journal Net. Published data were extracted independently by two authors using predefined database templates. The quality of the data from individual papers was also assessed. The effects of chemotherapy were compared with those of chemotherapy in combination with DC-CIK immunotherapy. The pooled analysis was performed using the data from random or fixed-effect models.

RESULTS: Seven trials matched our inclusion criteria (n = 533). The overall analysis showed significant survival benefit [one-year overall survival (OS), P < 0.0001; two-year OS, P = 0.009; three-year OS, P = 0.002] in favor of DC-CIK immunotherapy combined with chemotherapy. Disease-free survival (DFS) rate was improved after the combination of DC-CIK immunotherapy and chemotherapy (one-year DFS, P < 0.0001; two-year DFS, P = 0.002; three-year DFS, P = 0.02). An improved overall response rate (P = 0.009) was also observed in patients who received DC-CIK therapy. Furthermore, the analysis of T-lymphocyte subsets in peripheral blood indicated that the number of CD4⁺ T cells significantly increased in the DC-CIK plus chemotherapy group (P < 0.05).

CONCLUSION: The combination of DC-CIK immunotherapy and chemotherapy was superior in prolonging the survival time and enhancing immunological responses.

Cancer-initiating cells from colorectal cancer patients escape from T cell-mediated immunosurveillance in vitro through membrane-bound IL-4

Cancer-initiating cells (CICs) that are responsible for tumor initiation, propagation, and resistance to standard therapies have been isolated from human solid tumors, including colorectal cancer (CRC). The aim of this study was to obtain an immunological profile of CRC-derived CICs and to identify CIC-associated target molecules for T cell immunotherapy. We have isolated cells with CIC properties along with their putative non-CIC autologous counterparts from human primary CRC tissues. These CICs have been shown to display "tumor-initiating/stemness" properties, including the expression of CIC-associated markers (e.g., CD44, CD24, ALDH-1, EpCAM, Lgr5), multipotency, and tumorigenicity following injection in immunodeficient mice. The immune profile of these cells was assessed by phenotype analysis and by in vitro stimulation of PBMCs with CICs as a source of Ags. CICs, compared with non-CIC counterparts, showed weak immunogenicity. This feature correlated with the expression of high levels of immunomodulatory molecules, such as IL-4, and with CIC-mediated inhibitory activity for anti-tumor T cell responses. CIC-associated IL-4 was found to be responsible for this negative function, which requires cell-to-cell contact with T lymphocytes and which is impaired by blocking IL-4 signaling. In addition, the CRC-associated Ag COA-1 was found to be expressed by CICs and to represent, in an autologous setting, a target molecule for anti-tumor T cells. Our study provides relevant information that may contribute to designing new immunotherapy protocols to target CICs in CRC patients.

Perspectives on immunotherapy in prostate cancer and solid tumors: where is the future?

The goals of any cancer therapy are to improve disease control, palliate pain and improve overall survival. We are fortunate to have in our cancer armamentarium two new immune-directed therapies which not only impact on disease control but also on overall survival. The first, sipuleucel-T, a cellular-based vaccine, was approved for prostate cancer and was shown to be safe with minimal toxicity. The second, ipilimumab, a monoclonal antibody directed to an immunologic checkpoint molecule, showed a survival benefit in patients with advanced melanoma. Benefit appeared to correlate in some cases with the development of autoimmune events, signaling that the immune system is in overdrive against the cancer. Where we are and where we will likely go are the topics to be discussed in this review.

Review article: antitumoural immunity in colorectal cancer - current and potential future implications in clinical practice

BACKGROUND

Most of the current research in gastrointestinal oncology is focused on biology of cancer itself, but there is growing interest in the patient's immune system response and its relation with cancer cells.

AIM

To review the impact of the antitumoural immune response on epidemiology, prognosis and treatment of colorectal cancer.

METHODS

Search of the literature published in English using the PubMed database.

RESULTS

The role of the immune system in the antitumoural immunosurveillance is clearly supported by the increased incidence of colorectal cancer and adenomatous polyps in immunosuppressed patients. Moreover, the degree of infiltration of the tumours by the immune cells has been shown to be a strong prognostic factor of both disease recurrence and survival. The immune system plays an important role in the chemotherapy-induced cell death. New therapeutic strategies targeting the antitumoural immunity are being currently investigated with promising results.

CONCLUSION

Better knowledge of antitumoural immune system can have a major impact on patients' management in daily clinical practice. Colorectal cancer screening is an important issue in immunosuppressed patients, and recommendations should be refined for selected high-risk patients. The use of an immune score to guide the therapeutic strategies in the adjuvant setting should be supported. Further and larger clinical trials are necessary to accelerate the development of innovative immune therapies.

Dendritic cell immunotherapy in ovarian cancer

Ovarian cancer is one of the most frequent gynecological malignancies. However, as there is no effective screening method to detect early disease, it is usually only diagnosed when already widespread in the abdomen. The majority of patients diagnosed with advanced-stage disease will relapse and require additional therapy. In the search for additional effective treatments for the management of recurrent disease, researchers have focused on the potential usefulness of immunotherapeutic modulation by administering autologous immune cells, such as dendritic cells (DCs), to stimulate antitumor host responses. With the ultimate goal of improved survival, this review addresses mechanisms in ovarian cancer that may limit the expansion of antitumor immunity, discusses the parameters to be considered for optimal DC immunotherapy, outlines evaluation methodology used to monitor the success of treatment regimens and reviews reported DC immunotherapy trials in ovarian cancer.