Chemoimmunotherapy. Cancer J. 2010;16:295-303. [PMID: 20693839 DOI: 10.1097/ppo.0b013e3181eb5066]

TGF-β1 precursor and CD8 are potential prognostic and predictive markers in operated breast cancer

The transforming growth factor β1 (TGF-β1) and CD8-positive T cells are two important immune factors that function at opposite directions. The purpose of this study was to verify the relationship between the two factors and their associations with long-term effects of adjuvant chemotherapy or endocrine therapy in breast cancer. Expression of TGF-β1 precursor and CD8 was immunohistochemically detected on surgically-obtained tumor samples of 130 (stage I-III) invasive breast carcinomas from Chinese subjects, who were followed up for a mean time of 112 months. Interstitial CD8-positive cells and TGF-β1 precursor-positive cells adjacent to tumor nests were counted. Infiltration of CD8-positive lymphocytes into tumor nests and TGF-β1 precursor expression in tumor cells were observed and survival analysis was performed. Our results showed that density of interstitial CD8-positive lymphocytes was an independent adverse prognostic factor for distant disease-free survival (DDFS) (HR=8.416, 95% CI=1.636-43.292, P=0.011) in hormone receptor-positive patients who were on adjuvant endocrine therapy. For breast cancer patients who did not receive adjuvant chemotherapy, those without infiltration of CD8-positive cells into tumor nests had a shorter overall survival (OS) than their counterparts with CD8-positive cell infiltration into tumor nests (Log-Rank, P=0.003). But OS of patients without infiltration of CD8-positive cells into tumor nests was significantly prolonged by adjuvant chemotherapy (Log-Rank, P=0.013) and paralleled that of patients with CD8-positive cell infiltration. Although OS was shorter in the tumor cell TGF-β1 precursor (t-TGF-β1-pre)-positive patients than in the negative patients in patients without receiving chemotherapy (P=0.053), OS of t-TGF-β1-pre-positive patients was significantly prolonged by adjuvant chemotherapy (P=0.035) and was longer than that of t-TGF-β1-pre-negative patients. Analysis showed that t-TGF-β1-pre was an independent positive prognostic factor for DDFS (HR=0.392 95% CI=0.157-0.978, P=0.045) in patients who received adjuvant chemotherapy. This study suggested that density of interstitial CD8-positive lymphocytes was of prognostic value in hormone receptor-positive patients who received adjuvant endocrine therapy. Our study verified that adverse immunologic signatures consisting of absence of CD8-positive cells in tumor nests or expression of TGF-β1 precursor in tumor cells in breast cancer were associated with worse prognosis and significantly improved long-term survival with adjuvant chemotherapy, respectively.

Doxorubicin treatment induces tumor cell death followed by immunomodulation in a murine neuroblastoma model

Chemotherapy of malignant tumors induces tumor cell death. Numerous antitumor agents induce apoptosis of tumor cells, which are subsequently engulfed by phagocytes, initiating an immune reaction. The induction of immunogenic cell death by antitumor agents may be advantageous for antitumor immunity. The purpose of this study was to determine whether doxorubicin is capable of inducing an immunogenic reaction in murine neuroblastoma cells. The murine neuroblastoma cell line (neuro-2a cells) was cultured in a medium containing doxorubicin or cisplatin (CDDP), and induction of cell death was confirmed by cell viability assays. Cluster of differentiation (CD)8α⁺ lymphocytes were co-cultured with neuro-2a cells that had died following treatment with either doxorubicin or CDDP, and CD11b⁺ spleen cells or bone marrow-derived dendritic cells (BM-DCs) were added to the culture. Proliferation of CD8α⁺ lymphocytes and interferon (IFN)-γ production were evaluated. When CD8α⁺ cells were co-cultured with doxorubicin-treated neuro-2a cells and BM-DCs, CD8α⁺ cells reacted to anti-CD3/CD28 antibody stimulation, proliferated and increased IFN-γ production. IFN-γ production was more effectively promoted by co-culture with doxorubicin-treated neuro-2a cells than by co-culture with CDDP-treated neuro-2a cells. These findings suggest that doxorubicin is capable of inducing immunogenic cell death in neuroblastoma cells, and thus has an immunological advantage for chemotherapy of neuroblastoma compared with CDDP. BM-DCs are considered to be the key antigen-presenting cells in the immune reaction following the induction of immunogenic neuroblastoma cell death and phagocytosis.

Synergy between chemotherapeutic agents and CTLA-4 blockade in preclinical tumor models

Ipilimumab, a cytotoxic T-lymphocyte antigen-4 (CTLA-4) binding agent, has proven to be an effective monotherapy for metastatic melanoma and has shown antitumor activity in trials when administered with other therapeutic agents. We hypothesized that the combination of ipilimumab with chemotherapeutic agents, such as ixabepilone, paclitaxel, etoposide, and gemcitabine, may produce therapeutic synergy based on distinct but complementary mechanisms of action for each drug and unique cellular targets. This concept was investigated using a mouse homolog of ipilimumab in preclinical murine tumor models, including SA1N fibrosarcoma, EMT-6 mammary carcinoma, M109 lung carcinoma, and CT-26 colon carcinoma. Results of CTLA-4 blockade in combination with one of various chemotherapeutic agents demonstrate that synergy occurs in settings where either agent alone was not effective in inducing tumor regression. Furthermore, when combined with CTLA-4 blockade, ixabepilone, etoposide, and gemcitabine elicited prolonged antitumor effects in some murine models with induction of a memory immune response. Future investigations are warranted to determine which specific chemo-immunotherapy combinations, if any, will produce synergistic antitumor effects in the clinical setting.

Changes in the immune cell population and cell proliferation in peripheral blood after gemcitabine-based chemotherapy for pancreatic cancer

PURPOSE

Regulatory T cells (Tregs) play a role in the immunosuppressive state in pancreatic cancer patients. We aimed to evaluate the changes of immune cells population including Tregs caused by gemcitabine (GEM)-based chemotherapy.

METHODS

Fifty-three patients with pancreatic cancer were enrolled in this study, of which 32 received GEM- based chemotherapy. Blood samples were collected before and at least 2 weeks after the last dose of chemotherapy. The peripheral blood mononuclear cells (PBMCs) were subjected to flow cytometry analysis after labeling with anti-CD4, anti-CD25, and anti-Foxp3 antibodies. Other lymphocytes and NK cell markers were also measured. The proliferative capacity of PBMCs stimulated with anti-CD3 was analyzed using H(3) thymidine.

RESULTS

The percentage and number of Tregs were significantly decreased after chemotherapy (p = 0.032, p = 0.003, respectively). The other immune cells and the proliferative capacity did not change.

CONCLUSION

This study showed that GEM-based chemotherapy produced an immunomodulatory effect via the depletion of Tregs.

Prospects of combinatorial synthetic peptide vaccine-based immunotherapy against cancer

The insight that the immune system is involved in tumor resistance is gaining momentum and this has led to the development of immunotherapeutic strategies aiming at enhancement of immune-mediated tumor destruction. Although some of these strategies have moderate clinical benefit, most stand-alone therapies fail to significantly affect progressive disease and survival or do so only in a minority of patients. Research on the mechanisms underlying the generation of immune responses against tumors and the immune evasion by tumors has emphasized that various mechanisms simultaneously prevent effective immunity against cancer including inefficient presentation of tumor antigens by dendritic cells and induction of negative immune regulation by regulatory T-cells (Tregs) and myeloid derived suppressor cells (MDSCs). Thus the design of therapies that simultaneously improve effective tumor immunity and counteract immune evasion by tumors seems most desirable for clinical efficacy. As it is unlikely that a single immunotherapeutic strategy addresses all necessary requirements, combinatorial strategies that act synergistically need to be developed. Here we discuss the current knowledge and prospects of treatment with synthetic peptide vaccines that stimulate tumor-specific T-cell responses combined with adjuvants, immune modulating antibodies, cytokines and chemotherapy. We conclude that combinatorial approaches have the best potency to accomplish the most significant tumor destruction but further research is required to optimize such approaches.

A bystander cell-based GM-CSF secreting vaccine synergized with a low dose of cyclophosphamide presents therapeutic immune responses against murine hepatocellular carcinoma

Granulocyte-macrophage colony-stimulating factor (GM-CSF) secreting cellular tumor vaccines contribute to the induction of potent antitumor immune responses in murine models and patients suffering from cancers. Hepatocellular carcinoma (HCC) is one of the most frequent and malignant cancers in China. We describe, for the first time, a GM-CSF releasing vaccine strategy that represents a step toward combating this type of cancer. In this study, a bystander cell-based GM-CSF secreting vaccine against murine HCC, Hepa1-6/B78H1-GM-CSF, was co-administered with a low dose of cyclophosphamide (CY). After challenging with tumor and vaccination, immunological assays demonstrated that the cellular antitumor immune responses were efficiently activated and that tumor development was significantly retarded, which was dependent on synergy with CY. The promising outcome of the anti-HCC vaccine in the murine model demonstrates the feasibility of a future clinical application for this treatment in HCC patients.

FDG PET scans as evaluation of clinical response to dendritic cell vaccination in patients with malignant melanoma

BACKGROUND

Measurements of tumour metabolism by [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) have been successfully applied to monitor tumour response after chemo- and chemo-radiotherapy and may not have the same limitations as other morphological imaging techniques. In this study it is investigated whether FDG-PET might add information on the efficacy of immune therapy.

MATERIALS AND METHODS

In a retrospective analysis data from patients with advanced progressive melanoma, treated with DC vaccinations and evaluated by PET/CT scans at baseline as well as after 6 vaccinations were analysed. If a patient achieved stable disease according to RECIST, additional vaccinations were given. The PET scans were evaluated according to EORTC guidelines.

RESULTS

PET/CT scans from 13 patients were evaluated. According to RECIST 3 patients achieved stable disease and 10 patients progressed. Interestingly, when evaluated by PET scans 2 patients had partial metabolic response and 1 patient had complete metabolic response of the 2 index lesions even though a new lesion appeared simultaneously. Ten patients were seen to have stable or progressive metabolic disease.

CONCLUSION

By adding PET scans to the CT evaluation of patients treated with DC vaccines, a more detailed picture of the single lesions was found. This seems to improve the clinical evaluation of the treatment. The lack of correlation between the PET and CT scans suggests that some of the increases in target lesions seen in CT scans might be due to oedema or immune-infiltrates and not progression of the disease. Thus, further investigation into the contribution of PET scans to the evaluation of cancer immunotherapy is needed.

Breast cancer immunobiology driving immunotherapy: vaccines and immune checkpoint blockade

Breast cancer is immunogenic, and infiltrating immune cells in primary breast tumors convey important clinical prognostic and predictive information. Furthermore, the immune system is critically involved in clinical responses to some standard cancer therapies. Early breast cancer vaccine trials have established the safety and bioactivity of breast cancer immunotherapy, with hints of clinical activity. Novel strategies for modulating regulators of immunity, including regulatory T cells, myeloid-derived suppressor cells and immune checkpoint pathways (monoclonal antibodies specific for the cytotoxic T-lymphocyte antigen-4 or programmed death), are now available. In particular, immune checkpoint blockade has enormous therapeutic potential. Integrative breast cancer immunotherapies that strategically combine established breast cancer therapies with breast cancer vaccines, immune checkpoint blockade or both should result in durable clinical responses and increased cures.

Maintenance treatment with chemotherapy and immunotherapy in non-small cell lung cancer: a case report

A 53-years-old woman was diagnosed with lung adenocarcinoma state IV (synchronous pleural involvement) in April 2009. First-line systemic treatment included six cycles of Carboplatin, Paclitaxel, and Bevacizumab. Partial response was achieved. Maintenance therapy with Bevacizumab and Pemetrexed was given from September 2009 to February 2010. No response changes were observed. Immunotherapy was initiated, and then Pemetrexed was given with the same disease status. Both treatments were well tolerated. Immunotherapy toxicity included reaction at the site of injection grade 2. At present, the patient is still on this treatment. Given the poor prognosis of patients with advanced lung cancer, the combination of both treatments during the stable phase of the disease may improve progression-free survival.

Integration of autologous dendritic cell-based immunotherapy in the standard of care treatment for patients with newly diagnosed glioblastoma: results of the HGG-2006 phase I/II trial

PURPOSE

Dendritic cell (DC)-based tumor vaccination has rendered promising results in relapsed high-grade glioma patients. In the HGG-2006 trial (EudraCT 2006-002881-20), feasibility, toxicity, and clinical efficacy of the full integration of DC-based tumor vaccination into standard postoperative radiochemotherapy are studied in 77 patients with newly diagnosed glioblastoma.

PATIENTS AND METHODS

Autologous DC are generated after leukapheresis, which is performed before the start of radiochemotherapy. Four weekly induction vaccines are administered after the 6-week course of concomitant radiochemotherapy. During maintenance chemotherapy, 4 boost vaccines are given. Feasibility and progression-free survival (PFS) at 6 months (6mo-PFS) are the primary end points. Overall survival (OS) and immune profiling, rather than monitoring, as assessed in patients' blood samples, are the secondary end points. Analysis has been done on intent-to-treat basis.

RESULTS

The treatment was feasible without major toxicity. The 6mo-PFS was 70.1 % from inclusion. Median OS was 18.3 months. Outcome improved significantly with lower EORTC RPA classification. Median OS was 39.7, 18.3, and 10.7 months for RPA classes III, IV, and V, respectively. Patients with a methylated MGMT promoter had significantly better PFS (p = 0.0027) and OS (p = 0.0082) as compared to patients with an unmethylated status. Exploratory "immunological profiles" were built to compare to clinical outcome, but no statistical significant evidence was found for these profiles to predict clinical outcome.

CONCLUSION

Full integration of autologous DC-based tumor vaccination into standard postoperative radiochemotherapy for newly diagnosed glioblastoma seems safe and possibly beneficial. These results were used to power the currently running phase IIb randomized clinical trial.

Metastatic melanoma patients treated with dendritic cell vaccination, Interleukin-2 and metronomic cyclophosphamide: results from a phase II trial

Dendritic cells (DC) are the most potent antigen presenting cells and have proven effective in stimulation of specific immune responses in vivo. Competing immune inhibition could limit the clinical efficacy of DC vaccination. In this phase II trial, metronomic Cyclophosphamide and a Cox-2 inhibitor have been added to a DC vaccine with the intend to dampen immunosuppressive mechanisms. Twenty-eight patients with progressive metastatic melanoma were treated with autologous DCs pulsed with survivin, hTERT, and p53-derived peptides (HLA-A2(+)) or tumor lysate (HLA-A2(-)). Concomitantly the patients were treated with IL-2, Cyclophosphamide, and Celecoxib. The treatment was safe and tolerable. Sixteen patients (57 %) achieved stable disease (SD) at 1st evaluation and 8 patients had prolonged SD (7-13.7 months). The median OS was 9.4 months. Patients with SD had an OS of 10.5 months while patients with progressive disease (PD) had an OS of 6.0 months (p = 0.048) even though there were no differences in prognostic factors between the two groups. Despite the use of metronomic Cyclophosphamide, regulatory T cells did not decrease during treatment. Indirect IFN-γ ELISPOT assays showed a general increase in immune responses from baseline to the time of 4th vaccination. Induction of antigen-specific immune responses was seen in 9 out of 15 screened HLA-A2(+) patients. In conclusion, the number of patients obtaining SD more than doubled and 6-month survival significantly increased compared to a previous trial without Cyclophosphamide and Celecoxib. A general increase in immune responses against the tested peptides was observed.

Polyfunctional CD4⁺ T cells are essential for eradicating advanced B-cell lymphoma after chemotherapy

The finding that many chemotherapeutic agents have immunostimulatory effects has provided the impetus to combine chemotherapy and immunotherapy for synergistic antitumor effects. However, the critical determinants of effective antitumor immunity after chemotherapy have not been defined. Here we report that adoptive transfer of tumor-specific CD4⁺ T cells after chemotherapy with cyclophosphamide gave rise to polyfunctional CD4⁺ effector cells, which in turn intensified the inflammatory milieu and enhanced the activation of CD8⁺ T cells in the tumor microenvironment. Although this combined chemoimmunotherapy initially resulted in progressive regression of advanced B-cell lymphoma, its therapeutic efficacy was not durable and most mice succumbed to late relapse. Notably, relapse was associated with acquisition of a tolerized phenotype in tumor-specific CD4⁺ T cells, characterized by overexpression of program death-1 (PD-1). Remarkably, effective antitumor immunity was maintained and cure became prevalent when polyfunctional CD4⁺ effector cells were prevented from undergoing PD-1-mediated tolerization, either by antibody blockade of the PD-1-PD-L1 pathway, or targeted ablation of PD-1 in tumor-specific CD4⁺ T cells. Our study suggests that tumor-reactive CD4⁺ T cells act as the "gatekeepers" of the host antitumor immunity in the postchemotherapy setting, thereby their functional status governs the choice between eradication versus regrowth of residual tumors.

Ipilimumab in combination with paclitaxel and carboplatin as first-line therapy in extensive-disease-small-cell lung cancer: results from a randomized, double-blind, multicenter phase 2 trial

BACKGROUND

Ipilimumab, an anti-CTLA4 monoclonal antibody, demonstrated survival benefit in melanoma with immune-related (ir) adverse events (irAEs) managed by the protocol-defined guidelines. This phase 2 study evaluated ipilimumab+paclitaxel (Taxol)/carboplatin in extensive-disease-small-cell lung cancer (ED-SCLC).

DESIGN

Patients (n=130) with chemotherapy-naïve ED-SCLC were randomized 1: 1: 1 to receive paclitaxel (175 mg/m2)/carboplatin (area under the curve=6) with either placebo (control) or ipilimumab 10 mg/kg in two alternative regimens, concurrent ipilimumab (ipilimumab+paclitaxel/carboplatin followed by placebo+paclitaxel/carboplatin) or phased ipilimumab (placebo+paclitaxel/carboplatin followed by ipilimumab+paclitaxel/carboplatin). Treatment was administered every 3 weeks for a maximum of 18 weeks (induction), followed by maintenance ipilimumab or placebo every 12 weeks. End points included progression-free survival (PFS), irPFS, best overall response rate (BORR); irBORR, overall survival (OS), and safety.

RESULTS

Phased ipilimumab, but not concurrent ipilimumab, improved irPFS versus control [HR (hazard ratio)=0.64; P=0.03]. No improvement in PFS (HR=0.93; P=0.37) or OS (HR=0.75; P=0.13) occurred. Phased ipilimumab, concurrent ipilimumab and control, respectively, were associated with median irPFS of 6.4, 5.7 and 5.3 months; median PFS of 5.2, 3.9 and 5.2 months; median OS of 12.9, 9.1 and 9.9 months. Overall rates of grade 3/4 irAEs were 17, 21 and 9% for phased ipilimumab, concurrent ipilimumab and control, respectively.

CONCLUSION

These results suggest further investigation of ipilimumab in ED-SCLC.

Towards curative cancer immunotherapy: overcoming posttherapy tumor escape

The past decade has witnessed the evolvement of cancer immunotherapy as an increasingly effective therapeutic modality, evidenced by the approval of two immune-based products by the FDA, that is, the cancer vaccine Provenge (sipuleucel-T) for prostate cancer and the antagonist antibody against cytotoxic T-lymphocyte antigen-4 (CTLA-4) ipilimumab for advanced melanoma. In addition, the clinical evaluations of a variety of promising immunotherapy drugs are well under way. Benefiting from more efficacious immunotherapeutic agents and treatment strategies, a number of recent clinical studies have achieved unprecedented therapeutic outcomes in some patients with certain types of cancers. Despite these advances, however, the efficacy of most cancer immunotherapies currently under clinical development has been modest. A recurring scenario is that therapeutic maneuvers initially led to measurable antitumor immune responses in cancer patients but ultimately failed to improve patient outcomes. It is increasingly recognized that tumor cells can antagonize therapy-induced immune attacks through a variety of counterregulation mechanisms, which represent a fundamental barrier to the success of cancer immunotherapy. Herein we summarize the findings from some recent preclinical and clinical studies, focusing on how tumor cells advance their survival and expansion by hijacking therapy-induced immune effector mechanisms that would otherwise mediate their destruction.

Anticancer and immunostimulatory activity by conjugate of paclitaxel and non-toxic derivative of LPS for combined chemo-immunotherapy

PURPOSE

Cancer is a multifactorial syndrome; hence, multidimensional therapy with a chemo-immunotherapeutic conjugate could be more effective in curing the disease.

METHODS

We used SP-LPS, a bio-polymer having potent immunostimulatory activity, for conjugation with paclitaxel to make a chemo-immunotherapeutic conjugate. Its physicochemical characterization was done by HPLC, NMR and IR spectra. Stability was measured at different pH, temperature and in tissue homogenates. Chemotherapeutic and immunostimulatory activity was evaluated in vitro and also in tumor microenvironment.

RESULTS

The conjugate self assembled into nanoparticulate structure, probably due to micelle formation. Stability was pH and temperature dependent. The conjugate exhibited chemotherapeutic and immunotherapeutic activity in vitro. In vivo antitumor activity was significantly higher and a higher percentage of activated immune cells were found in the tumor microenvironment of the conjugate-treated mice as compared to Taxol®-treated group.

CONCLUSIONS

This conjugate is a potential chemo-immunotherapeutic compound for the treatment of cancer with advantages over present day chemotherapy with Taxol in terms of higher anticancer activity, less toxicity and ease of delivery.

Ipilimumab in combination with paclitaxel and carboplatin as first-line treatment in stage IIIB/IV non-small-cell lung cancer: results from a randomized, double-blind, multicenter phase II study

PURPOSE

Ipilimumab, which is an anti-cytotoxic T-cell lymphocyte-4 monoclonal antibody, showed a survival benefit in melanoma with adverse events (AEs) managed by protocol-defined guidelines. A phase II study in lung cancer assessed the activity of ipilimumab plus paclitaxel and carboplatin.

PATIENTS AND METHODS

Patients (N = 204) with chemotherapy-naive non-small-cell lung cancer (NSCLC) were randomly assigned 1:1:1 to receive paclitaxel (175 mg/m(2)) and carboplatin (area under the curve, 6) with either placebo (control) or ipilimumab in one of the following two regimens: concurrent ipilimumab (four doses of ipilimumab plus paclitaxel and carboplatin followed by two doses of placebo plus paclitaxel and carboplatin) or phased ipilimumab (two doses of placebo plus paclitaxel and carboplatin followed by four doses of ipilimumab plus paclitaxel and carboplatin).Treatment was administered intravenously every 3 weeks for ≤ 18 weeks (induction). Eligible patients continued ipilimumab or placebo every 12 weeks as maintenance therapy. Response was assessed by using immune-related response criteria and modified WHO criteria. The primary end point was immune-related progression-free survival (irPFS). Other end points were progression-free survival (PFS), best overall response rate (BORR), immune-related BORR (irBORR), overall survival (OS), and safety.

RESULTS

The study met its primary end point of improved irPFS for phased ipilimumab versus the control (hazard ratio [HR], 0.72; P = .05), but not for concurrent ipilimumab (HR, 0.81; P = .13). Phased ipilimumab also improved PFS according to modified WHO criteria (HR, 0.69; P = .02). Phased ipilimumab, concurrent ipilimumab, and control treatments were associated with a median irPFS of 5.7, 5.5, and 4.6 months, respectively, a median PFS of 5.1, 4.1, and 4.2 months, respectively, an irBORR of 32%, 21% and 18%, respectively, a BORR of 32%, 21% and 14%, respectively, and a median OS of 12.2, 9.7, and 8.3 months. Overall rates of grade 3 and 4 immune-related AEs were 15%, 20%, and 6% for phased ipilimumab, concurrent ipilimumab, and the control, respectively. Two patients (concurrent, one patient; control, one patient) died from treatment-related toxicity.

CONCLUSION

Phased ipilimumab plus paclitaxel and carboplatin improved irPFS and PFS, which supports additional investigation of ipilimumab in NSCLC.

Re-purposing cancer therapeutics for breast cancer immunotherapy

After decades of work to develop immune-based therapies for cancer, the first drugs designed specifically to engage the host anti-tumor immune response for therapeutic benefit were recently approved for clinical use. Sipuleucel-T, a vaccine for advanced prostate cancer, and ipilimumab, a monoclonal antibody that mitigates the negative impact of cytotoxic T lymphocyte antigen-4 signaling on tumor immunity, provide a modest clinical benefit in some patients. The arrival of these drugs in the clinic is a significant advance that we can capitalize on for even better clinical outcomes. The strategic and scientifically rational integration of vaccines and other direct immunomodulators with standard cancer therapeutics should lead to therapeutic synergy and high rates of tumor rejection. This review focuses on the use of cyclophosphamide, doxorubicin, and HER-2-specific monoclonal antibodies to dissect mechanisms of immune tolerance relevant to breast cancer patients and illustrates how appropriate preclinical models can powerfully inform clinical translation. The immune-modulating activity of targeted, pathway-specific, small molecule therapeutics is also discussed. Fully understanding how cancer drugs impact the immune system should lead to the ultimate personalized cancer medicine: effective combinatorial immunotherapy strategies that simultaneously target signaling pathways essential for tumor growth and progression, and systematically break multiple, distinct immune tolerance pathways to maximize tumor rejection and effect cure.

Very small size proteoliposomes derived from Neisseria meningitidis: an effective adjuvant for antigen-specific cytotoxic T lymphocyte response stimulation under leukopenic conditions

Leukopenia is a severe condition resulting from both pathological processes and some treatments, like chemotherapy in cancer patients. However, the activation of the patient immune system is required for the success of immunotherapeutic strategies, as cancer vaccines. In this regard, leukopenia constitutes a major hurdle to overcome, mainly due to the impairment of cytotoxic T lymphocyte (CTL) responses. Adjuvants are basic components of vaccine formulations, which might be useful to stimulate immunity under this immunosuppressed condition. To this aim, we tested the capacity of a novel nanoparticulated complex, very small size proteoliposomes (VSSP), to promote CTL even in a leukopenic scenario. Noteworthy, we observed that a VSSP-based OVA vaccine induced a normal antigen-specific CTL response in mice rendered leukopenia by the administration of high doses of the chemotherapeutic agent cyclophosphamide (CY), while under the same conditions the OVA antigen formulated in the TLR-3 agonist polyinosinic-polycytidylic acid (P(I:C)) was ineffective. Moreover, an appropriate combination of VSSP with the P(I:C) vaccine was able to restore the CD8(+) T cell effector function in leukopenic mice. VSSP induced not only a faster repopulation of immune cells in CY-receiving animals, but also enhanced the recovery of memory T lymphocytes and myeloid dendritic cells (DCs) while simultaneously abrogated the immunosuppressive capacity of myeloid-derived suppressor cells (MDSCs). Our results suggest that VSSP could be a particularly suitable immunomodulator to be used in CTL-promoting active immunotherapy strategies operating in severe immune compromised scenarios.

Immunotherapy for metastatic colorectal cancer: present status and new options

Although no immunotherapeutic treatment is approved for colorectal cancer (CRC) patients, promising results from clinical trials suggest that several immunotherapeutic strategies may prove efficacious and applicable to this group of patients. This review describes the immunogenicity of CRC and presents the most interesting strategies investigated so far: cancer vaccination including antigen-defined vaccination and dendritic cell vaccination, chemo-immunotherapy, and adoptive cell transfer. Future treatment options as well as the possibility of combining existing therapies will be discussed along with the challenges presented by tumor escape mechanisms.

Chemotherapeutics and radiation stimulate MHC class I expression through elevated interferon-beta signaling in breast cancer cells

Low doses of anticancer drugs have been shown to enhance antitumor immune response and increase the efficacy of immunotherapy. The molecular basis for such effects remains elusive, although selective depletion of T regulatory cells has been demonstrated. In the current studies, we demonstrate that topotecan (TPT), a topoisomerase I-targeting drug with a well-defined mechanism of action, stimulates major histocompatibility complex class I (MHC I) expression in breast cancer cells through elevated expression/secretion of interferon-β (IFN-β) and activation of type I IFN signaling. First, we show that TPT treatment elevates the expression of both total and cell-surface MHC I in breast cancer cells. Second, conditioned media from TPT-treated breast cancer ZR-75-1 cells induce elevated expression of cell-surface MHC I in drug-naïve recipient cells, suggesting the involvement of cytokines and/or other secreted molecules. Consistently, TPT-treated cells exhibit elevated expression of multiple cytokines such as IFN-β, TNF-α, IL-6 and IL-8. Third, either knocking down the type I interferon receptor subunit 1 (IFNAR1) or addition of neutralizing antibody against IFN-β results in reduced MHC I expression in TPT-treated cells. Together, these results suggest that TPT induces increased IFN-β autocrine/paracrine signaling through type I IFN receptor, resulting in the elevated MHC I expression in tumor cells. Studies have also demonstrated that other chemotherapeutic agents (e.g. etoposide, cisplatin, paclitaxel and vinblastine) similarly induce increased IFN-β secretion and elevated MHC I expression. In addition, conditioned media from γ-irradiated donor cells are shown to induce IFN-β-dependent MHC I expression in unirradiated recipient cells. In the aggregate, our results suggest that many cancer therapeutics induce elevated tumor antigen presentation through MHC I, which could represent a common mechanism for enhanced antitumor immune response through T cell cytotoxicity during metronomic chemotherapy, as well as increased efficacy of combined chemo- (or radio-)/immuno-therapy.

Tumor-infiltrating lymphocytes predict response to anthracycline-based chemotherapy in estrogen receptor-negative breast cancer

Introduction

Infiltration of breast tumors by tumor-infiltrating lymphocytes (TIL) has been associated with sensitivity to anthracycline-based chemotherapy. However, it is unclear whether this is true within the estrogen receptor-alpha (ER)-negative subset of breast tumors that frequently manifest high TIL levels.

Methods

The association of TIL with short-term and long-term clinical response to anthracycline-based therapy was assessed in two independent ER-negative breast cancer cohorts in which patients were categorized as TIL-high or TIL-low. We defined an eight-gene lymphocyte mRNA expression signature (including CD19, CD3D, CD48, GZMB, LCK, MS4A1, PRF1, and SELL) and used unsupervised hierarchical clustering to examine the association between TIL and short-term response to neoadjuvant chemotherapy in a previously published cohort of ER-negative tumors (n = 113). We also examined the association between TIL and long-term chemotherapeutic efficacy in a second cohort of ER-negative tumors (n = 255) with longer than 6 years of median follow-up by using tissue microarrays and immunohistochemistry (IHC) for detection of CD3, CD8, CD4, CD20, and TIA-1.

Results

In patients with ER-negative tumors treated with neoadjuvant anthracycline-based chemotherapy, pathologic complete responses (pCRs) were achieved by 23 (74%) of 31 TIL-high patients and 25 (31%) of 80 TIL-low patients (odds ratio (OR), 6.33; 95% confidence interval (CI), 2.49 to 16.08; P < 0.0001). Multivariate logistic regression with standard clinicopathologic features demonstrated that only tumor size (P = 0.037) and TIL status (P = 0.001) were independent predictors of anthracycline response. In the second cohort, adjuvant anthracycline-based therapy was associated with increased disease-free survival (DFS) only in patients with high levels of intraepithelial CD3⁺ TIL (P = 0.0023). In contrast, outcomes after CMF treatment (cyclophosphamide, methotrexate, and fluorouracil) showed no association with CD3 status. In both cohorts, cytotoxic T-cells were the primary TIL subtype associated with anthracycline sensitivity. Finally, TIL significantly predicted anthracycline sensitivity for both the Her2-positive and triple-negative tumor phenotypes.

Conclusions

ER-negative breast cancers with high levels of TIL have heightened sensitivity to anthracycline-based chemotherapy, as assessed by the immediate response to neoadjuvant therapy and long-term outcome following adjuvant therapy. Investigations of TIL-based predictive tests to identify patients likely to benefit from anthracycline-based treatments are warranted.

Exploitation of the propulsive force of chemotherapy for improving the response to cancer immunotherapy

Since the early clinical studies of cancer immunotherapy, the question arose as to whether it was possible to combine it with standard cancer treatments, mostly chemotherapy. The answer, now, is past history. The combined use of immunotherapy and chemotherapy is not only possible but, in certain cases, can be advantageous, depending on the drug, the dose and the combination modalities. In order to find the best synergisms between the two treatments and to turn weak immunotherapeutic interventions into potent anticancer instruments, it is mandatory to understand the complex mechanisms responsible for the positive interactions between chemotherapy and immunotherapy. In this article, we review the current knowledge on mechanisms involved in the immunostimulating activity of chemotherapy and summarize the main studies in both mouse models and patients aimed at exploiting such mechanisms for enhancing the response to cancer immunotherapy.

Targeting myeloid regulatory cells in cancer by chemotherapeutic agents

Recent findings in humans and numerous experimental models provide evidence of the important role of immune regulatory cells in cancer and various diseases. "Myeloid regulatory cells" (MRC) include myeloid-derived suppressor cells, regulatory dendritic cells, regulatory macrophages, and subsets of granulocytes that expand during pathologic conditions and that have the ability to suppress cellular immunity. A decrease in MRC population and/or activity has been shown to have positive immune-potentiating effects. Several clinical trials have thus been initiated with the goal of manipulating the expansion or activation of these cells and thereby improving patient immune responses. New data from our own and other laboratories recently revealed that ultralow noncytotoxic doses of certain chemotherapeutic drugs could up-regulate antitumor immunity by modulating the formation, differentiation, and/or function of MRC. This new phenomenon, termed "chemomodulation," allows for the regulation of the tumor microenvironment without the undesirable toxic effects associated with conventional chemotherapy. However, further studies are required before this new targeted therapy can find its way to patients with cancer.

Targeted chemoimmunotherapy using drug-loaded aptamer-dendrimer bioconjugates

We reported an innovative, targeted chemoimmuno drug-delivery system. Although chemoimmunotherapy, as an alternative to or in combination with conventional therapeutic systems, has been in the forefront of recent oncological research, as presently configured, such systems face several major obstacles for efficient clinical application. Here, we establish a novel nano-platform for effective chemoimmunotherapy designed to overcome the drawbacks of conventional cancer therapies, describing a delivery system based on a dendrimer and a single-strand DNA-A9 PSMA (prostate-specific membrane antigen) RNA aptamer hybrid. Employing these vehicles, we demonstrate the promising possibility of this chemoimmuno therapeutic system against prostate cancer in in vivo and in vitro models.

Control of advanced cancer: the road to chronicity

Despite the recent trend toward a slight decrease in age-adjusted cancer mortality in some countries, crude mortality rates will continue to increase, driven by the demographic shift towards an aged population. Small molecules (small molecules and biologics) are not only a new therapeutic acquisition, but the tools of a more fundamental transition: the transformation of cancer from a rapidly fatal disease into a chronic condition. Antibodies and cancer vaccines can be used for a long time, even beyond progressive disease, and in aged patients, usually unfit for more aggressive conventional treatments. However, this transition to chronicity will require novel developmental guidelines adequate to this kind of drugs, for which optimal dose is not usually the maximal tolerated dose, pharmacokinetics does not define treatment schedule, and tumor shrinkage is not a good correlate of survival. The ongoing cancer immunotherapy program (including several monoclonal antibodies and therapeutic vaccines) at the Centre of Molecular Immunology can illustrate the issues to be addressed, both biological and social, along the path to transform advanced cancer into a chronic non-communicable disease compatible with years of quality life.

GM-CSF-secreting vaccines for solid tumors: moving forward

Cancer vaccines consisting of intact tumor cells genetically modified to secrete the cytokine granulocyte-macrophage colony-stimulating factor (GM-CSF) have undergone extensive preclinical development. These vaccines induce the massive accumulation of dendritic cells at the intradermal injection site, which engulf, process, and present tumor antigens to activate tumor-specific T cells. Early phase clinical testing demonstrated promising evidence of safety and bioactivity, although initial phase III clinical trials were unsuccessful. Together, the preclinical and clinical data argue for the continued clinical development of these vaccines, integrating them with standard and novel cancer therapeutics that enhance vaccine activity by overcoming immune tolerance and suppression, and/or augmenting co-stimulatory pathways of T cell activation.