An overview of cancer immunotherapy

Thetumor microenvironment'sinpancreatic cancer:Effects onimmunotherapy successandnovel strategiestoovercomethehostile environment

Cancer is a significant global health issue that poses a considerable burden on both patients and healthcare systems. Many different types of cancers exist that often require unique treatment approaches and therapies. A hallmark of tumor progression is the creation of an immunosuppressive environment, which poses complex challenges for current treatments. Amongst the most explored characteristics is a hypoxic environment, high interstitial pressure, and immunosuppressive cells and cytokines. Traditional cancer treatments involve radiotherapy, chemotherapy, and surgical procedures. The advent of immunotherapies was regarded as a promising approach with hopes of greatly increasing patients' survival and outcome. Although some success is seen with various immunotherapies, the vast majority of monotherapies are unsuccessful. This review examines how various aspects of the tumor microenvironment (TME) present challenges that impede the success of immunotherapies. Subsequently, we review strategies to manipulate the TME to facilitate the success of immunotherapies.

Alzheimer's Disease Immunotherapy: Current Strategies and Future Prospects

Alzheimer's disease (AD) is an extremely complex and heterogeneous pathology influenced by many factors contributing to its onset and progression, including aging, amyloid-beta (Aβ) plaques, tau fibril accumulation, inflammation, etc. Despite promising advances in drug development, there is no cure for AD. Although there have been substantial advancements in understanding the pathogenesis of AD, there have been over 200 unsuccessful clinical trials in the past decade. In recent years, immunotherapies have been at the forefront of these efforts. Immunotherapy alludes to the immunological field that strives to identify disease treatments via the enhancement, suppression, or induction of immune responses. Interestingly, immunotherapy in AD is a relatively new approach for non-infectious disease. At present, antibody therapy (passive immunotherapy) that targets anti-Aβ aimed to prevent the fibrillization of Aβ peptides and disrupt pre-existing fibrils is a predominant AD immunotherapy due to the continuous failure of active immunotherapy for AD. The most rational and safe strategies will be those targeting the toxic molecule without triggering an abnormal immune response, offering therapeutic advantages, thus making clinical trial design more efficient. This review offers a concise overview of immunotherapeutic strategies, including active and passive immunotherapy for AD. Our review encompasses approved methods and those presently under investigation in clinical trials, while elucidating the recent challenges, complications, successes, and potential treatments. Thus, immunotherapies targeting Aβ throughout the disease progression using a mutant oligomer-Aβ stimulated dendritic cell vaccine may offer a promising therapy in AD.

The Role of Microbiota-Derived Vitamins in Immune Homeostasis and Enhancing Cancer Immunotherapy

Not all cancer patients who receive immunotherapy respond positively and emerging evidence suggests that the gut microbiota may be linked to treatment efficacy. Though mechanisms of microbial contributions to the immune response have been postulated, one likely function is the supply of basic co-factors to the host including selected vitamins. Bacteria, fungi, and plants can produce their own vitamins, whereas humans primarily obtain vitamins from exogenous sources, yet despite the significance of microbial-derived vitamins as crucial immune system modulators, the microbiota is an overlooked source of these nutrients in humans. Microbial-derived vitamins are often shared by gut bacteria, stabilizing bioenergetic pathways amongst microbial communities. Compositional changes in gut microbiota can affect metabolic pathways that alter immune function. Similarly, the immune system plays a pivotal role in maintaining the gut microbiota, which parenthetically affects vitamin biosynthesis. Here we elucidate the immune-interactive mechanisms underlying the effects of these microbially derived vitamins and how they can potentially enhance the activity of immunotherapies in cancer.

PD-1/PD-L1 and DNA Damage Response in Cancer

The application of immunotherapy for cancer treatment is rapidly becoming more widespread. Immunotherapeutic agents are frequently combined with various types of treatments to obtain a more durable antitumor clinical response in patients who have developed resistance to monotherapy. Chemotherapeutic drugs that induce DNA damage and trigger DNA damage response (DDR) frequently induce an increase in the expression of the programmed death ligand-1 (PD-L1) that can be employed by cancer cells to avoid immune surveillance. PD-L1 exposed on cancer cells can in turn be targeted to re-establish the immune-reactive tumor microenvironment, which ultimately increases the tumor's susceptibility to combined therapies. Here we review the recent advances in how the DDR regulates PD-L1 expression and point out the effect of etoposide, irinotecan, and platinum compounds on the anti-tumor immune response.

The Immune System as a Therapeutic Target for Alzheimer’s Disease

Alzheimer’s disease (AD) is a heterogeneous neurodegenerative disorder and is the most common cause of dementia. Furthermore, aging is considered the most critical risk factor for AD. However, despite the vast amount of research and resources allocated to the understanding and development of AD treatments, setbacks have been more prominent than successes. Recent studies have shown that there is an intricate connection between the immune and central nervous systems, which can be imbalanced and thereby mediate neuroinflammation and AD. Thus, this review examines this connection and how it can be altered with AD. Recent developments in active and passive immunotherapy for AD are also discussed as well as suggestions for improving these therapies moving forward.

Harnessing the Immune System with Cancer Vaccines: From Prevention to Therapeutics

Prophylactic vaccination against infectious diseases is one of the most successful public health measures of our lifetime. More recently, therapeutic vaccination against established diseases such as cancer has proven to be more challenging. In the host, cancer cells evade immunologic regulation by multiple means, including altering the antigens expressed on their cell surface or recruiting inflammatory cells that repress immune surveillance. Nevertheless, recent clinical data suggest that two classes of antigens show efficacy for the development of anticancer vaccines: tumor-associated antigens and neoantigens. In addition, many different vaccines derived from antigens based on cellular, peptide/protein, and genomic components are in development to establish their efficacy in cancer therapy. Some vaccines have shown promising results, which may lead to favorable outcomes when combined with standard therapeutic approaches. This review provides an overview of the innate and adaptive immune systems, their interactions with cancer cells, and the development of various different vaccines for use in anticancer therapeutics.

Gut Microbiota: A Promising Milestone in Enhancing the Efficacy of PD1/PD-L1 Blockade Therapy

In the past few decades, immunotherapy has emerged as one of the most promising strategies among current treatments of cancer. In particular, the field of PD1/PD-L1 inhibitors has been boosted, widely applied into clinical practice with potent therapeutic efficacy and remarkable survival benefits on various cancers such as melanoma, non-small cell lung cancer (NSCLC), and urothelial carcinoma (UC). However, the application of PD1/PD-L1 blockade therapy is still quite restricted because of unexpected toxicities, limited response rate, as well as associated resistance. In consequence, searching for potential strategies that possibly resolve the existing limitations and enhance the therapeutic responsiveness of PD1/PD-L1 blockade is of great significance. Fortunately, the gut microbiome has been demonstrated to serve as a pivotal regulator in anti-PD1/PD-L1 therapy, providing an applicable tool to improve anti-PD1/PD-L1 clinical efficacy. In this review, we summarized published advancements about how microbiota modulated in anti-PD1/PD-L1 therapy and illustrated its underlying mechanisms, giving insights into putative manipulation of gut microbiota to facilitate PD1/PD-L1 blockade.

Exploring the application of immunotherapy against HIV infection in the setting of malignancy: A detailed review article

According to the Joint United Nations Programme on HIV/AIDS (UNAIDS), as of 2019, approximately 42.2 million people have died from acquired immunodeficiency syndrome (AIDS)-related illnesses since the start of the epidemic. Antiretroviral therapy (ART) has significantly reduced mortality, morbidity, and incidence of the human immunodeficiency virus (HIV)/AIDS-defining cancers, taming once-dreaded disease into a benign chronic infection. Although the treatment has prolonged the patients' survival, general HIV prevalence has increased and this increase has dovetailed with an increasing incidence of Non-AIDS-defining cancers (NADCs) among people living with HIV (PLWH). This is happening when new promising approaches in both oncology and HIV infection are being developed. This review focuses on recent progress witnessed in immunotherapy approaches against HIV-related, Non-AIDS-defining cancers (NADCs), and HIV infection.

A novel nano therapeutic using convalescent plasma derived exosomal (CPExo) for COVID-19: A combined hyperactive immune modulation and diagnostics

Extracellular vesicles like exosomes are important therapeutic tactics for treating COVID -19. By utilizing convalescent plasma derived exosomes (CPExo) from COVID-19 recovered persistence could accelerate the treatment strategies in the current state of affairs. Adequate literature has shown that administering the exosome to the in vivo system could be beneficial and could target the pathogens in an effective and precise manner. In this hypothesis we highlight the CPExo instead of convalescent plasma (CP), perhaps to dispense of exosomes are gratified and it's more effectively acquired immune response conferral through antibodies. COVID-19 convalescent plasma has billions of exosomes and it has aptitudes to carry molecular constituents like proteins, lipids, RNA and DNA, etc. Moreover, exosomes are capable of recognizing antigens with adequate sensitivity and specificity. Many of these derivatives could trigger an immune modulation into the cells and act as an epigenetic inheritor response to target pathogens through RNAs. COIVID-19 resistance activated plasma-derived exosomes are either responsible for the effects of plasma beyond the contained immune antibodies or could be inhibitory. The proposed hypothesis suggests that preselecting the plasma-derived antibodies and RNAs merged exosomes would be an optimized therapeutic tactic for COVID-19 patients. We suggest that, the CPExo has a multi-potential effect for treatment efficacy by acting as immunotherapeutic, drug carrier, and diagnostic target with noncoding genetic materials as a biomarker.

Diet, Microbiome, and Cancer Immunotherapy-A Comprehensive Review

The immune system plays a key role in cancer suppression. Immunotherapy is widely used as a treatment method in patients with various types of cancer. Immune checkpoint blockade using antibodies, such as anti-PD-1, anti-PD-L1, and anti-CTLA-4, is currently gaining popularity. A systematic literature search was executed, and all available data was summarized. This review shows that specific dietary patterns (such as, e.g., animal-based, vegetarian, or Mediterranean diet) alter the gut microbiome's composition. An appropriate intestinal microbiota structure might modulate the function of human immune system, which affects the bodily anti-cancer response. This paper shows also that specific bacteria species inhabiting the gastrointestinal tract can have a beneficial influence on the efficacy of immunotherapy. Antibiotics weaken gut bacteria and worsen the immune checkpoint blockers' efficacy, whereas a faecal microbiota transplant or probiotics supplementation may help restore bacterial balance in the intestine. Other factors (like vitamins, glucose, or BMI) change the cancer treatment response, as well. This review demonstrates that there is a strong association between one's diet, gut microbiome composition, and the outcome of immunotherapy. However, further investigation on this subject is required.

On-Chip Biogenesis of Circulating NK Cell-Derived Exosomes in Non-Small Cell Lung Cancer Exhibits Antitumoral Activity

As the recognition between natural killer (NK) cells and cancer cells does not require antigen presentation, NK cells are being actively studied for use in adoptive cell therapies in the rapidly evolving armamentarium of cancer immunotherapy. In addition to utilizing NK cells, recent studies have shown that exosomes derived from NK cells also exhibit antitumor properties. Furthermore, these NK cell-derived exosomes exhibit higher stability, greater modification potentials and less immunogenicity compared to NK cells. Therefore, technologies that allow highly sensitive and specific isolation of NK cells and NK cell-derived exosomes can enable personalized NK-mediated cancer therapeutics in the future. Here, a novel microfluidic system to collect patient-specific NK cells and on-chip biogenesis of NK-exosomes is proposed. In a small cohort of non-small cell lung cancer (NSCLC) patients, both NK cells and circulating tumor cells (CTCs) were isolated, and it is found NSCLC patients have high numbers of NK and NK-exosomes compared with healthy donors, and these concentrations show a trend of positive and negative correlations with bloodborne CTC numbers, respectively. It is further demonstrated that the NK-exosomes harvested from NK-graphene oxide chip exhibit cytotoxic effect on CTCs. This versatile system is expected to be used for patient-specific NK-based immunotherapies along with CTCs for potential prognostic/diagnostic applications.

[Basic principles of immunotherapy]

Immunotherapy for malignant diseases is defined as a systematic therapeutic approach that aims to target the individual's immune system to prevent the development of malignancies or to combat existing tumors. Nowadays, this includes various therapeutic approaches, such as immune checkpoint inhibitors, BiTEs (bispecific T‑cell engagers), CAR T‑cells (CAR: chimeric antigen receptors) and oncolytic viruses, which have not only different mechanisms of action and points of attack, but also have very different efficiencies in the treatment of solid and hematological malignancies. These approaches undoubtedly enrich the therapeutic portfolio in oncology-in palliative systematic therapy and also in the interaction with operative and ablative local therapeutic approaches.

Immunological Aspects of Malignant Gliomas

Glioblastoma Multiforme (GBM) is the most common malignant primary brain neoplasm having a mean survival time of <24 months. This figure remains constant, despite significant progress in medical research and treatment. The lack of an efficient anti-tumor immune response and the micro-invasive nature of the glioma malignant cells have been explained by a multitude of immune-suppressive mechanisms, proven in different models. These immune-resistant capabilities of the tumor result in a complex interplay this tumor shares with the immune system. We present a short review on the immunology of GBM, discussing the different unique pathological and molecular features of GBM, current treatment modalities, the principles of cancer immunotherapy and the link between GBM and melanoma. Current knowledge on immunological features of GBM, as well as immunotherapy past and current clinical trials, is discussed in an attempt to broadly present the complex and formidable challenges posed by GBM.

Immunostimulation by OX40 Ligand Transgenic Ewing Sarcoma Cells

Interleukin-2 (IL-2) transgenic Ewing sarcoma cells can induce tumor specific T and NK cell responses and reduce tumor growth in vivo and in vitro. Nevertheless, the efficiency of this stimulation is not high enough to inhibit tumor growth completely. In addition to recognition of the cognate antigen, optimal T-cell stimulation requires signals from so-called co-stimulatory molecules. Several members of the tumor necrosis factor superfamily have been identified as co-stimulatory molecules that can augment antitumor immune responses. OX40 (CD134) and OX40 ligand (OX40L = CD252; also known as tumor necrosis factor ligand family member 4) is one example of such receptor/ligand pair with co-stimulatory function. In the present investigation, we generated OX40L transgenic Ewing sarcoma cells and tested their immunostimulatory activity in vitro. OX40L transgenic Ewing sarcoma cells showed preserved expression of Ewing sarcoma-associated (anti)gens including lipase member I, cyclin D1 (CCND1), cytochrome P450 family member 26B1 (CYP26B1), and the Ewing sarcoma breakpoint region 1-friend leukemia virus integration 1 (EWSR1-FLI1) oncogene. OX40L-expressing tumor cells showed a trend for enhanced immune stimulation against Ewing sarcoma cells in combination with IL-2 and stimulation of CD137. Our data suggest that inclusion of the OX40/OX40L pathway of co-stimulation might improve immunotherapy strategies for the treatment of Ewing sarcoma.

Novel cancer therapies: treatments driven by tumour biology

The traditional view is that treatments within oncology largely consist of chemotherapy, which aims to maximise damage to the rapidly dividing cancer cells but often at the expense of normal cells and overall quality of life for the patient. The development of anticancer drugs has changed from the serendipitous discoveries of the past, to today's purposeful targeting of cancer cells which takes advantage of novel technological developments and a greater understanding of tumour biology. The aim of these new treatments is to affect the essential function of the cancer cell while sparing normal cells, and limiting side effects. The phenotypic characteristics of tumours, such as unregulated growth signalling, development of new vascular systems and the evasion of immune destruction are used to identify potential drug targets. Here we review the clinical evidence and molecular mechanisms for novel therapies that are currently in use and those that are in development.

Semi-allogeneic dendritic cells injected via the intratumoural injection route show efficient antitumour effects in cooperation with host-derived professional antigen-presenting cells

Dendritic cells (DC)-based immunotherapy is a potent anticancer modality. In DC-based immunotherapy, allogeneic DC may be an alternative source, but the usefulness of allogeneic DC in DC-based immunotherapy is still controversial. When used for immunotherapy, three factors may affect the efficiency of an allogeneic DC-driven antitumour response: (1) survival time, which is affected by T-cell alloresponses; (2) major histocompatibility complex incompatibility with the host cells in the context of antigen presentation; and (3) the role of host-derived professional antigen-presenting cells (pAPC). In addition, it is unclear which injection route is preferable when using allogeneic DC. In this study, we demonstrate that semi-allogeneic DC, which share half of the genes of the recipient, are more effective when used via the intratumoural (i.t.) injection route, rather than the subcutaneous (s.c.) injection route, for the induction of efficient antitumour effects and the generation of a significant tumour-specific CD8(+) T-cell response. The i.t. route has the advantage of not requiring ex vivo pulsation with tumour lysates or tumour antigens, because the i.t.-injected DC can engulf tumour antigens in situ. Allogeneic bone marrow transplantation (BMT) models, which permit us to separately assess the three factors described previously, show that while all three factors are important for efficient antitumour effects, the control of the alloresponse to injected DC is the most crucial for host-derived pAPC to function well when DC are administered intratumourally. This information may be useful for DC-based cancer immunotherapy under circumstances that do not allow for the use of autologous DC.

Cytokines (TH1 and TH2) in patients with advanced cervical cancer undergoing neoadjuvant chemoradiation: correlation with treatment response

BACKGROUND AND OBJECTIVES

Host factors are critical in regulating tumor growth, and cytokines that modulate immunological control may be of importance in cervical cancer. To study this, the cytokines were measured in peripheral blood mononuclear cells in women with cervical cancer, before and after neoadjuvant chemoradiation, and assessed their correlation with therapeutic response.

METHODS

Ninety patients with advanced cervical cancer and 90 healthy controls were enrolled, and human papillomavirus status was determined. Cytokines were estimated by enzyme-linked immunosorbent assay in pretreatment samples after chemotherapy, brachyradiation, and after follow-up. Response to therapy was assessed during and after therapy and after 1 and 3 years of follow-up.

RESULTS

Pretreatment levels of type 1 cytokines (IL-2 and IFN-gamma) showed significant decrease, whereas type 2 cytokines (IL-4 and IL-10) showed significant increase in patients versus controls. After chemotherapy, a mild increase in type 1 cytokine levels was observed in complete responders versus partial/nonresponders, which became highly significant after completion of therapy and remained significant during follow-up. A slight decrease in type 2 cytokine levels was seen in complete responders versus partial/nonresponders, which remained insignificant for IL-10 even after chemoradiation.

CONCLUSIONS

This important finding suggests that pretreatment type 1 cytokine levels and the extent of their change during treatment can predict the therapeutic response to neoadjuvant chemoradiation in advanced cervical cancer.

Dendritic cells modified to express fractalkine/CX3CL1 in the treatment of preexisting tumors

Fractalkine (CX3CL1) is a unique membrane-bound CX3C chemokine that serves as a potent chemoattractant for lymphocytes. The hypothesis of this study is that dendritic cells (DC) genetically modified ex vivo to overexpress fractalkine would enhance the T cell-mediated cellular immune response with a consequent induction of anti-tumor immunity to suppress tumor growth. To prove this hypothesis, established tumors of different mouse cancer cells (B16-F10 melanoma, H-2b, and Colon-26 colon adenocarcinoma, H-2d) were treated with intratumoral injection of bone marrow-derived DC that had been modified in vitro with an RGD fiber-mutant adenovirus vector expressing mouse fractalkine (Ad-FKN). In both tumor models tested, treatment of tumor-bearing mice with Ad-FKN-transduced DC gave rise to a significant suppression of tumor growth along with survival advantages in the treated mice. Immunohistochemical analysis of tumors treated with direct injection of Ad-FKN-transduced DC demonstrated that the treatment prompted CD8+ T cells and CD4+ T cells to accumulate in the tumor milieu, leading to activation of immune-relevant processes. Consistent with the finding, the intratumoral administration of Ad-FKN-transduced DC evoked tumor-specific cytotoxic T lymphocytes, which ensued from in vivo priming of Th1 immune responses in the treated host. In addition, the anti-tumor effect provided by intratumoral injection of Ad-FKN-transduced DC was completely abrogated in CD4+ T cell-deficient mice as well as in CD8+ T cell-deficient mice. These results support the concept that genetic modification of DC with a recombinant fractalkine adenovirus vector may be a useful strategy for cancer immunotherapy protocols.

Assessment of dendritic cell number and radiosensitivity in laryngeal tumours

OBJECTIVES

Radiotherapy is one of the principal treatment modalities for many types of head and neck tumour; what effects the dendritic cell (DC) population may have on treatment outcome have not been critically evaluated in laryngeal cancer.

DESIGN

Retrospective, case-controlled study using immunohistochemistry to investigate the presence of S-100 positive DC in pre-treatment, archival biopsy tissue of early stage laryngeal cancers.

SETTING

Patients with laryngeal cancer treated with radiotherapy in Head and Neck Departments in England.

PARTICIPANTS

Patients diagnosed with early stage laryngeal cancer, treated with single modality radiotherapy with curative intent. Radioresistant tumours (n = 22), defined as recurrent tumours within 12 months of therapy. Radiosensitive tumours (n = 22), defined as no recurrence with a minimum follow-up of 36 months.

MAIN OUTCOME MEASURES

Density of S-100 staining DC on three x200 magnified microscopic fields.

RESULTS

DC were present in approximately equal numbers in both radioresistant and radiosensitive laryngeal tumour pre-treatment biopsies and therefore density did not correlate with radiotherapy treatment outcome (P = 0.420).

CONCLUSION

There is no intrinsic deficiency in DC number in radioresistant laryngeal tumours meaning that such tumours could potentially benefit from vaccination strategies that enhance the specific anti-tumour immune response.

Activation-induced cell death limits effector function of CD4 tumor-specific T cells

A number of studies have documented a critical role for tumor-specific CD4(+) cells in the augmentation of immunotherapeutic effector mechanisms. However, in the context of an extensive tumor burden, chronic stimulation of such CD4(+) T cells often leads to the up-regulation of both Fas and Fas ligand, and coexpression of these molecules can potentially result in activation-induced cell death and the subsequent loss of effector activity. To evaluate the importance of T cell persistence in an experimental model of immunotherapy, we used DO11 Th1 cells from wild-type, Fas-deficient, and Fas ligand-deficient mice as effector populations specific for a model tumor Ag consisting of an OVA-derived transmembrane fusion protein. We found that the prolonged survival of Fas-deficient DO11 Th1 cells led to a more sustained tumor-specific response both in vitro and in vivo. Importantly, both Fas- and Fas ligand-deficient Th1 cells delayed tumor growth and cause regression of established tumors more effectively than wild-type Th1 cells, indicating that resistance to activation-induced cell death significantly enhances T cell effector activity.

Adenovirus Vector-Mediated in Vivo Gene Transfer of OX40 Ligand to Tumor Cells Enhances Antitumor Immunity of Tumor-Bearing Hosts

OX40 ligand (OX40L), the ligand for OX40 on activated CD4+ T cells, has adjuvant properties for establishing effective T-cell immunity, a potent effector arm of the immune system against cancer. The hypothesis of this study is that in vivo genetic engineering of tumor cells to express OX40L will stimulate tumor-specific T cells by the OX40L-OX40 engagement, leading to an induction of systemic antitumor immunity. To investigate this hypothesis, s.c. established tumors of three different mouse cancer cells (B16 melanoma, H-2b; Lewis lung carcinoma, H-2b; and Colon-26 colon adenocarcinoma, H-2d) were treated with intratumoral injection of a recombinant adenovirus vector expressing mouse OX40L (AdOX40L). In all tumor models tested, treatment of tumor-bearing mice with AdOX40L induced a significant suppression of tumor growth along with survival advantages in the treated mice. The in vivo AdOX40L modification of tumors evoked tumor-specific cytotoxic T lymphocytes in the treated host correlated with in vivo priming of T helper 1 immune responses in a tumor-specific manner. Consistent with the finding, the antitumor effect provided by intratumoral injection of AdOX40L was completely abrogated in a CD4+ T cell-deficient or CD8+ T cell-deficient condition. In addition, ex vivo AdOX40L-transduced B16 cells also elicited B16-specific cytotoxic T lymphocyte responses, and significantly suppressed the B16 tumor growth in the immunization-challenge experiment. All of these results support the concept that genetic modification of tumor cells with a recombinant OX40L adenovirus vector may be of benefit in cancer immunotherapy protocols.

Efficient delivery of DNA to dendritic cells mediated by influenza virosomes

In an attempt to enhance the immunological efficacy of DNA-based vaccines, we have investigated a new biological means for delivering target gene DNA directly to professional antigen presenting cells (APC), such as the dendritic cells (DC), which are ultimately responsible for the antigen presentation and the primary activation of the immune system. For this purpose we investigated influenza virosomes (IRIV) with assembled DNA as a possible biological carrier for targeting the APC in vivo and in vitro. By cytofluorimetric analysis of the draining lymph nodes of Balb/c mice which had received (by intranasal (in.) administration) FITC-labeled DNA assembled with IRIV, we detected a significant labeled DNA uptake in a subset of lymph node deriving cells expressing DC surface markers. Subsequent mRNA analysis of these lymph nodes showed that the trans-gene delivered by the virosomes was effectively expressed as mRNA. Finally, a further cytofluorimetric analysis performed on human DC-enriched-PMBC, infected in vitro with labeled DNA/IRIV lead to the conclusion that the majority of APC (DC, B lymphocytes and CD16+ cells) are able to incorporate the labeled DNA transported by the construct. These findings suggest that the virosome is an efficient delivery system for testing infectious, as well as anti-cancer, DNA-based vaccine research.

A trial of IRX-2 in patients with squamous cell carcinomas of the head and neck

A Phase II trial in 42 patients with squamous cell cancer of the head and neck (H and NSCC) was performed using a combination immunotherapy with 10-20 days of perilymphatic injections of a natural cytokine mixture (NCM: IRX-2; 200 units IL-2 equivalence) preceded by low dose cyclophosphamide (CY; 300 mg/m(2)) and followed by daily oral indomethacin (25 mg t.i.d.) and zinc (65 mg in a multivitamin preparation). Thirty-nine patients underwent subsequent surgical resection and 22 stage IV patients received additional radiotherapy. Forty-two percent were adjudged to have complete and partial clinical responses (>50% tumor reduction); an additional five patients had minor responses for a total of 58%. Comparison of post-treatment biopsies or surgical specimens showed 90% of patients had reduction in tumor area from 79% to 48% (over half of which was fragmented) and increased area of leukocyte infiltration from 9% to 32% (79% of which was lymphoid). The treatment with IRX-2 was not associated with significant side effects and 24 of patients showed improvement in eating, breathing or phonation or reduced pain and bleeding. Fifteen patients with lymphocytopenia (lymphocyte counts [LC] less than or equal to 1500 mm(3)) showed significant increases in LC, CD3+, CD4+ and CD8+ T lymphocytes of 401, 147, 95 and 100/mm(3), respectively. Analysis of outcome of 32 on protocol patients after 36 months versus 32 concurrent institutional H and NSCC controls showed delayed recurrences and significant increases in mean survival time (MST) and survival (p's<0.02). The data document immunotherapy induced regression of H and NSCC with delayed recurrence and improved mean survival time.

On the biological relevance of MHC class II and B7 expression by tumour cells in melanoma metastases

A large number of studies have indicated that specific immune reactivity plays a crucial role in the control of malignant melanoma. In this context, expression of MHC I, MHC II and B7 molecules by melanoma cells is seen as relevant for the immune response against the tumour. For a better understanding of the biological relevance of MHC II and B7 expression by tumour cells in metastatic melanoma, we studied the expression of these molecules in melanoma metastases in relation to the inflammatory response, regression of the tumour and survival from 27 patients treated with biochemotherapy (30 mg m(-2) Cisplatin and 250 mg m(-2) decarbazine (dimethyl-triazene-imidazole-carboxamide, DTIC) on days 1-3 i.v., and 10(7) IU IFN-alpha 2b 3 days a week s.c., q. 28d). In 19 out of 27 lesions studied, we found expression of MHC II by the tumour cells, while only in one out of 11 tumour biopsies obtained from untreated metastatic melanoma patients, MHC II expression was detected. Expression of B7.1 and B7.2 by tumour cells was found in nine out of 24 and 19 out of 24 lesions, respectively. In all cases where B7.1 expression was found, expression of B7.2 by the tumour cells was also seen. In general, no or only few inflammatory cells positive for B7 were found. Expression of MHC II by tumour cells was positively correlated with the presence of tumour-infiltrating lymphocytes, regression of the lesion, and with time to progression (TTP) and overall survival (OS) of the patient. However, no significant correlation between B7.1 or B7.2 expression and regression of the tumour, TTP or OS was found. In light of other recent findings, these data altogether do support a role as biomarker for MHC II expression by tumour cells; however, its exact immunological pathomechanism(s) remain to be established.

Rational approaches to human cancer immunotherapy

Over most of the 20th century, immunotherapy for cancer was based on empiricism. Interesting phenomena were observed in the areas of cancer, infectious diseases, or transplantation. Inferences were made and extrapolated into new approaches for the treatment of cancer. If tumors regressed, the treatment approaches could be refined further. However, until the appropriate tools and reagents were available, investigators were unable to understand the biology underlying these observations. In the early 1990s, the first human tumor T cell antigens were defined and dendritic cells were discovered to play a pivotal role in antigen presentation. The current era of cancer immunotherapy is one of translational research based on known biology and rationally designed interventions and has led to a rapid expansion of the field. The beginning of the 21st century brings the possibility of a new era of effective cancer immunotherapy, combining rational, immunological treatments with conventional therapies to improve the outcome for patients with cancer.

Tumor suppression induced by intratumor administration of adenovirus vector expressing NK4, a 4-kringle antagonist of hepatocyte growth factor, and naive dendritic cells

NK4, a 4-kringle antagonist of hepatocyte growth factor (HGF), is a potent inhibitor of tumor angiogenesis and functions independently of its HGF-antagonistic activity. We have shown previously that in vivo genetic modification of tumors with an adenovirus vector that expresses NK4 (AdNK4) restrains tumor angiogenesis and slows the rate of tumor growth in vivo. In the present study, we investigated the hypothesis that this can be made more efficient by also administering bone marrow-generated dendritic cells (DCs) to the tumor. The data show that the growth of mouse subcutaneous tumors is significantly suppressed by direct administration of DCs into established tumors that had been pretreated with AdNK4 3 days previously. The synergistic antitumor effect produced by the combination therapy of AdNK4 with DCs correlated with the in vivo priming of tumor-specific cytotoxic T lymphocytes. Analysis of mice treated with fluorescence-labeled DCs suggested that DCs injected into the flank tumor could migrate to lymphoid organs in vivo for activation of immune-relevant processes. Knockout mice experiments demonstrated that the tumor regression produced by this combination therapy depends on both major histocompatibility complex (MHC) class I antigen presentation of DCs injected into the tumors and CD8(+) T cells of the treated host. Finally, a mechanism for this synergism was suggested by the histological observation that tumor necrosis and apoptosis were induced by genetic engineering of the tumors to express NK4. These findings should be useful in designing novel strategies that use a combination of 2 monotherapies directed against the vascular and immune systems for cancer therapy.

Tumour-associated antigen (TAA)-specific cytotoxic T cell (CTL) response in vitro and in a mouse model, induced by TAA-plasmids delivered by influenza virosomes

We investigated influenza virosomes as a TAA-gene delivery system for use in TAA-directed anti-cancer vaccine therapy. An engineered plasmid (GC90) expressing the parathyroid hormone-related peptide (PTH-rP), a protein secreted by prostate and lung carcinoma cells, was included in influenza virosomes (GC90V). The ability of GC90V to elicit a PTH-rP-specific cytotoxic T cell (CTL) response was demonstrated in BALB/c mice immunised with intranasal (i.n.) GC90V+/-adjuvant subcutaneous (s.c.) interleukin-2 (IL-2). A PTH-rP-specific CTL response with antitumour activity was also demonstrated in human peripheral blood mononuclear cells (PBMC) stimulated in vitro with GC90V infected autologous dendritic cells (DC). These results provide a rationale for investigating GC90V in clinical trials of anticancer vaccine therapy.

A fresh look at tumor immunosurveillance and immunotherapy

Despite major advances in our understanding of adaptive immunity and dendritic cells, consistent and durable responses to cancer vaccines remain elusive and active immunotherapy is still not an established treatment modality. The key to developing an effective anti-tumor response is understanding why, initially, the immune system is unable to detect transformed cells and is subsequently tolerant of tumor growth and metastasis. Ineffective antigen presentation limits the adaptive immune response; however, we are now learning that the host's innate immune system may first fail to recognize the tumor as posing a danger. Recent descriptions of stress-induced ligands on tumor cells recognized by innate effector cells, new subsets of T cells that regulate tumor tolerance and the development of spontaneous tumors in mice that lack immune effector molecules, beckon a reflection on our current perspectives on the interaction of transformed cells with the immune system and offer new hope of stimulating therapeutic immunity to cancer.

Cancer gene therapy: developments to 2000

Cancer, at the molecular level, continues to be more thoroughly understood. With this understanding comes the opportunity for innovative therapeutic intervention. Gene therapy remains an attractive concept to treat cancer. However, a number of gene therapy clinical trials have now been reported and it is clear that barriers remain before gene therapy gains widespread clinical application. This article outlines current directions and novel developments in the field of cancer gene therapy, which attempt to overcome these obstacles.