Tumor antigens heterogeneity and immune response-targeting neoantigens in breast cancer.

Breast cancer is both the most common type of cancer and the most frequent cause of cancer mortality in women, mainly because of its heterogeneity and limited immunogenicity. The aim of specific active cancer immunotherapy is to stimulate the host's immune response against cancer cells directly using a vaccine platform carrying one or more tumor antigens. In particular, the ideal tumor antigen should be able to elicit T cell and B cell responses, be specific for the tumor and be expressed at high levels on cancer cells. Neoantigens are ideal targets for immunotherapy because they are exclusive to individual patient's tumors, are absent in healthy tissues and are not subject to immune tolerance mechanisms. Thus, neoantigens should generate a specific reaction towards tumors since they constitute the largest fraction of targets of tumor-infiltrating T cells. In this review, we describe the technologies used for neoantigen discovery, the heterogeneity of neoantigens in breast cancer and recent studies of breast cancer immunotherapy targeting neoantigens.

Combined treatment with inhibitors of ErbB Receptors and Hh signaling pathways is more effective than single treatment in reducing the growth of malignant mesothelioma both in vitro and in vivo.

Malignant mesothelioma (MM) is a rare orphan aggressive neoplasia with low survival rates. Among the other signaling pathways, ErbB receptors and Hh signaling are deregulated in MM. Thus, molecules involved in these signaling pathways could be used for targeted therapy approaches. The aim of this study was to evaluate the effects of inhibitors of Hh- (GANT-61) and ErbB receptors (Afatinib)-mediated signaling pathways, when used alone or in combination, on growth, cell cycle, cell death and autophagy, modulation of molecules involved in transduction pathways, in three human MM cell lines of different histotypes. The efficacy of the combined treatment was also evaluated in a murine epithelioid MM cell line both in vitro and in vivo. This study demonstrated that combined treatment with two inhibitors counteracting the activation of two different signaling pathways involved in neoplastic transformation and progression, such as those activated by ErbB and Hh signaling, is more effective than the single treatments in reducing MM growth in vitro and in vivo. This study may have clinical implications for the development of targeted therapy approaches for MM.

Infection by High-Risk Human Papillomaviruses, Epithelial-to-Mesenchymal Transition and Squamous Pre-Malignant or Malignant Lesions of the Uterine Cervix: A Series of Chained Events?

Wound healing requires static epithelial cells to gradually assume a mobile phenotype through a multi-step process termed epithelial-to-mesenchymal transition (EMT). Although it is inherently transient and reversible, EMT perdures and is abnormally activated when the epithelium is chronically exposed to pathogens: this event deeply alters the tissue and eventually contributes to the development of diseases. Among the many of them is uterine cervical squamous cell carcinoma (SCC), the most frequent malignancy of the female genital system. SCC, whose onset is associated with the persistent infection of the uterine cervix by high-risk human papillomaviruses (HR-HPVs), often relapses and/or metastasizes, being resistant to conventional chemo- or radiotherapy. Given that these fearsome clinical features may stem, at least in part, from the exacerbated and long-lasting EMT occurring in the HPV-infected cervix; here we have reviewed published studies concerning the impact that HPV oncoproteins, cellular tumor suppressors, regulators of gene expression, inflammatory cytokines or growth factors, and the interactions among these effectors have on EMT induction and cervical carcinogenesis. It is predictable and desirable that a broader comprehension of the role that EMT inducers play in SCC pathogenesis will provide indications to flourish new strategies directed against this aggressive tumor.

In vivo and in vitro inhibition of osteosarcoma growth by the pan Bcl-2 inhibitor AT-101.

Osteosarcoma (OS) is the most common primary malignant bone tumor and mainly affects children and adolescents. The OS five-year survival rate remains very low. Thus, novel therapeutic protocols for the treatment of OS are needed. Several approaches targeting deregulated signaling pathways have been proposed. The antitumoral effects of polyphenols, which are naturally occurring compounds with potent antioxidant and anti-inflammatory activity, have been investigated in different tumors. Gossypol, which is a natural polyphenolic aldehyde isolated from the seeds of the cotton plant, has been shown to exert antitumoral activity in leukemia and lymphoma and in breast, head and neck, colon and prostate cancers. Therefore, in this study, we evaluated the effect of AT-101, which is the (-) enantiomer and more active form of gossypol, on the growth of human and murine OS cells in vitro and in vivo. Several clinical trials employing AT-101 have been performed, and some clinical trials are ongoing. Our results showed for the first time that AT-101 significantly inhibits OS cell growth in a dose- and time-dependent manner, inducing apoptosis and necrosis and partially activating autophagy. Our results demonstrated that AT-101 inhibits prosurvival signaling pathways depending on Akt, p38 MAPK and JNK. In addition, treatment with AT-101 increases the survival of OS-bearing mice. Overall, these results suggest that AT-101 is a candidate chemo-supportive molecule for the development of novel chemotherapeutic protocols for the treatment of OS.

Polyphenol-Mediated Autophagy in Cancer: Evidence of In Vitro and In Vivo Studies.

One of the hallmarks of cellular transformation is the altered mechanism of cell death. There are three main types of cell death, characterized by different morphological and biochemical features, namely apoptosis (type I), autophagic cell death (type II) and necrosis (type III). Autophagy, or self-eating, is a tightly regulated process involved in stress responses, and it is a lysosomal degradation process. The role of autophagy in cancer is controversial and has been associated with both the induction and the inhibition of tumor growth. Autophagy can exert tumor suppression through the degradation of oncogenic proteins, suppression of inflammation, chronic tissue damage and ultimately by preventing mutations and genetic instability. On the other hand, tumor cells activate autophagy for survival in cellular stress conditions. Thus, autophagy modulation could represent a promising therapeutic strategy for cancer. Several studies have shown that polyphenols, natural compounds found in foods and beverages of plant origin, can efficiently modulate autophagy in several types of cancer. In this review, we summarize the current knowledge on the effects of polyphenols on autophagy, highlighting the conceptual benefits or drawbacks and subtle cell-specific effects of polyphenols for envisioning future therapies employing polyphenols as chemoadjuvants.

Multifaceted Role of the Placental Growth Factor (PlGF) in the Antitumor Immune Response and Cancer Progression.

The sharing of molecules function that affects both tumor growth and neoangiogenesis with cells of the immune system creates a mutual interplay that impairs the host's immune response against tumor progression. Increasing evidence shows that tumors are able to create an immunosuppressive microenvironment by recruiting specific immune cells. Moreover, molecules produced by tumor and inflammatory cells in the tumor microenvironment create an immunosuppressive milieu able to inhibit the development of an efficient immune response against cancer cells and thus fostering tumor growth and progression. In addition, the immunoediting could select cancer cells that are less immunogenic or more resistant to lysis. In this review, we summarize recent findings regarding the immunomodulatory effects and cancer progression of the angiogenic growth factor namely placental growth factor (PlGF) and address the biological complex effects of this cytokine. Different pathways of the innate and adaptive immune response in which, directly or indirectly, PlGF is involved in promoting tumor immune escape and metastasis will be described. PlGF is important for building up vascular structures and functions. Although PlGF effects on vascular and tumor growth have been widely summarized, its functions in modulating the immune intra-tumoral microenvironment have been less highlighted. In agreement with PlGF functions, different antitumor strategies can be envisioned.

Polyphenols as Immunomodulatory Compounds in the Tumor Microenvironment: Friends or Foes?

Polyphenols are natural antioxidant compounds ubiquitously found in plants and, thus, ever present in human nutrition (tea, wine, chocolate, fruits and vegetables are typical examples of polyphenol-rich foods). Widespread evidence indicate that polyphenols exert strong antioxidant, anti-inflammatory, anti-microbial and anti-cancer activities, and thus, they are generally regarded to as all-purpose beneficial nutraceuticals or supplements whose use can only have a positive influence on the body. A closer look to the large body of results of years of investigations, however, present a more complex scenario where polyphenols exert different and, sometimes, paradoxical effects depending on dose, target system and cell type and the biological status of the target cell. Particularly, the immunomodulatory potential of polyphenols presents two opposite faces to researchers trying to evaluate their usability in future cancer therapies: on one hand, these compounds could be beneficial suppressors of peri-tumoral inflammation that fuels cancer growth. On the other hand, they might suppress immunotherapeutic approaches and give rise to immunosuppressive cell clones that, in turn, would aid tumor growth and dissemination. In this review, we summarize knowledge of the immunomodulatory effects of polyphenols with a particular focus on cancer microenvironment and immunotherapy, highlighting conceptual pitfalls and delicate cell-specific effects in order to aid the design of future therapies involving polyphenols as chemoadjuvants.

(±)-Gossypol induces apoptosis and autophagy in head and neck carcinoma cell lines and inhibits the growth of transplanted salivary gland cancer cells in BALB/c mice.

Racemic Gossypol [(±)-GOS], composed of both (-)-GOS and (+)-GOS, is a small BH3-mimetic polyphenol derived from cotton seeds. (±)-GOS has been employed and well tolerated by cancer patients. Head and neck carcinoma (HNC) represents one of the most fatal cancers worldwide, and a significant proportion of HNC expresses high levels of antiapoptotic Bcl-2 proteins. In this study, we demonstrate that (±)-GOS inhibits cell proliferation and induces apoptosis and autophagy of human pharynx, tongue, and salivary gland cancer cell lines and of mouse salivary gland cancer cells (SALTO). (±)-GOS was able to: (a) decrease the ErbB2 protein expression; (b) inhibit the phosphorylation of ERK1/2 and AKT; (c) stimulate p38 and JNK1/2 protein phosphorylation. (±)-GOS administration was safe in BALB/c mice and it reduced the growth of transplanted SALTO cells in vivo and prolonged mice median survival. Our results suggest the potential role of (±)-GOS as an antitumor agent in HNC patients.

Violacein, an indole-derived purple-colored natural pigment produced by Janthinobacterium lividum, inhibits the growth of head and neck carcinoma cell lines both in vitro and in vivo.

Violacein (VIO; 3-[1,2-dihydro-5-(5-hydroxy-1H-indol-3-yl)-2-oxo-3H-pyrrol-3-ylidene]-1,3-dihydro-2H-indol-2-one), an indole-derived purple-colored pigment, produced by a limited number of Gram-negative bacteria species, including Chromobacterium violaceum and Janthinobacterium lividum, has been demonstrated to have anti-cancer activity, as it interferes with survival transduction signaling pathways in different cancer models. Head and neck carcinoma (HNC) represents the sixth most common and one of the most fatal cancers worldwide. We determined whether VIO was able to inhibit head and neck cancer cell growth both in vitro and in vivo. We provide evidence that VIO treatment of human and mouse head and neck cancer cell lines inhibits cell growth and induces autophagy and apoptosis. In fact, VIO treatment increased PARP-1 cleavage, the Bax/Bcl-2 ratio, the inhibition of ERK1 and ERK2 phosphorylation, and the expression of light chain 3-II (LC3-II). Moreover, VIO was able to induce p53 degradation, cytoplasmic nuclear factor kappa B (NF-κB) accumulation, and reactive oxygen species (ROS) production. VIO induced a significant increase in ROS production. VIO administration was safe in BALB/c mice and reduced the growth of transplanted salivary gland cancer cells (SALTO) in vivo and prolonged median survival. Taken together, our results indicate that the treatment of head and neck cancer cells with VIO can be useful in inhibiting in vivo and in vitro cancer cell growth. VIO may represent a suitable tool for the local treatment of HNC in combination with standard therapies.

Macrophage induced gelsolin in response to Group B Streptococcus (GBS) infection.

Group B Streptococcus (GBS) has evolved several strategies to avoid host defences. We have shown that interaction of macrophages with GBS causes macrophage calpain activation, cytoskeletal disruption and apoptosis, consequences of intracellular calcium increase induced by membrane permeability alterations provoked by GBS-ß-haemolysin. Open question remains about what effect calcium influx has on other calcium-sensing proteins such as gelsolin, involved in cytoskeleton modulation and apoptosis. Therefore we analysed the effect of GBS-III-COH31:macrophage interaction on gelsolin expression. Here we demonstrate that an early macrophage response to GBS-III-COH31 is a very strong gelsolin increase, which occurs in a time- and infection-ratio-dependent manner. This is not due to transcriptional events, translation events, protein turnover alterations, or protein-kinase activation, but to calcium influx, calpain activation and caspase-3 degradation. In fact, EGTA and PD150606 (calpain inhibitor) prevented gelsolin increase while BAF (caspase inhibitor) enhanced it. Since gelsolin increase is induced by highly ß-haemolytic GBS-III-NEM316 and GBS-V-10/84, but not by weakly ß-haemolytic GBS, or GBS-III-COH31 in conditions suppressing ß-haemolysin expression/activity and the presence of dipalmitoylphosphatidylcholine (ß-haemolysin inhibitor), GBS-ß-haemolysin is solely responsible for gelsolin increase causing, through membrane permeability defects, calcium influx and calpain activation. Early gelsolin increase could represent a macrophage response to antagonize apoptosis since gelsolin knockdown increases macrophage susceptibility to GBS-induced apoptosis. This response seems to be GBS specific because macrophage apoptosis by Staurosporine or Cycloeximide does not induce gelsolin.

Natural humoral immune response to ribosomal P0 protein in colorectal cancer patients.

BACKGROUND: Tumor associated antigens are useful in colorectal cancer (CRC) management. The ribosomal P proteins (P0, P1, P2) play an important role in protein synthesis and tumor formation. The immunogenicity of the ribosomal P0 protein in head and neck, in breast and prostate cancer patients and the overexpression of the carboxyl-terminal P0 epitope (C-22 P0) in some tumors were reported. METHODS: Sera from 72 colorectal tumor patients (67 malignant and 5 benign tumors) were compared with 73 healthy donor sera for the presence of antibodies to CEA, EGFR, ErbB2 and ribosomal P proteins by western blotting or ELISA. Expression of the C-22 P0 epitope on tissues and colon cancer cells was determined by immunoperoxidase staining and indirect immunofluorescence/western blotting, respectively, employing MAb 2B2. Biological effects of MAb 2B2 on colon cancer cells were assessed by the Sulforhodamine B cell proliferation assay, trypan blue exclusion test and cleaved caspase-3 detection. Fisher's exact test was used to compare the number of auto-antibodies positive patients with healthy donors. Variation in the C-22 P0 expression, and in the number of apoptotic cells was evaluated by Student's t-test. Variation in cell survival and cell death was evaluated by Newman-Keuls test. RESULTS: No significant humoral response was observed to CEA, EGFR and ErbB2 in CRC patients. Conversely, 7 out of 67 CRC patient sera reacted to ribosomal P proteins. The prevalence of P proteins auto-antibodies in CRC patients was significant. Five patients showed restricted P0 immunoreactivity, while two patients reacted simultaneously to all P proteins. The C-22 P0 epitope was homogenously expressed both in malignant tumors and the adjacent mucosa, but the intensity of expression was higher in the tumor. Starved colon cancer cells showed a higher C-22 P0 epitope plasma membrane expression compared to control cells. MAb 2B2 inhibited colon cancer cell growth and induced cell death in a dose dependent manner. CONCLUSIONS: Our study shows a spontaneous humoral immune response to ribosomal P0 protein in CRC patients and the inhibition of in vitro cancer cell growth after C-22 P0 epitope targeting. The ribosomal P0 protein might be a useful immunological target in CRC patients.

In vitro and in vivo antitumoral effects of combinations of polyphenols, or polyphenols and anticancer drugs: perspectives on cancer treatment.

Carcinogenesis is a multistep process triggered by genetic alterations that activate different signal transduction pathways and cause the progressive transformation of a normal cell into a cancer cell. Polyphenols, compounds ubiquitously expressed in plants, have anti-inflammatory, antimicrobial, antiviral, anticancer, and immunomodulatory properties, all of which are beneficial to human health. Due to their ability to modulate the activity of multiple targets involved in carcinogenesis through direct interaction or modulation of gene expression, polyphenols can be employed to inhibit the growth of cancer cells. However, the main problem related to the use of polyphenols as anticancer agents is their poor bioavailability, which might hinder the in vivo effects of the single compound. In fact, polyphenols have a poor absorption and biodistribution, but also a fast metabolism and excretion in the human body. The poor bioavailability of a polyphenol will affect the effective dose delivered to cancer cells. One way to counteract this drawback could be combination treatment with different polyphenols or with polyphenols and other anti-cancer drugs, which can lead to more effective antitumor effects than treatment using only one of the compounds. This report reviews current knowledge on the anticancer effects of combinations of polyphenols or polyphenols and anticancer drugs, with a focus on their ability to modulate multiple signaling transduction pathways involved in cancer.

Intratumoral delivery of recombinant vaccinia virus encoding for ErbB2/Neu inhibits the growth of salivary gland carcinoma cells.

BACKGROUND: The antitumor activity induced by intratumoral vaccination with poxvirus expressing a tumor antigen was shown to be superior to that induced by subcutaneous vaccination. Salivary gland carcinomas overexpress ErbB2. Trastuzumab, a monoclonal antibody to ErbB2, was proposed for salivary gland tumors treatment. We explored the effectiveness of intratumoral vaccination with the recombinant vaccinia virus ErbB2/Neu (rV-neuT) vaccine in hampering the growth of transplanted Neu-overexpressing BALB-neuT salivary gland cancer cells (SALTO) in BALB-neuT mice. METHODS: BALB-neuT male mice were subcutaneously injected with SALTO tumor cells and intratumorally vaccinated twice with different doses of either rV-neuT or V-wt (wild-type). Tumors were measured weekly. The presence of anti-ErbB2/Neu antibodies was assayed by ELISA, immunoprecipitation or indirect immunofluorescence. Biological activity of immune sera was investigated by analyzing antibody-dependent cellular cytotoxicity (ADCC), SALTO cells proliferation and apoptosis, ErbB2/Neu receptor down regulation and ERK1/2 phosphorylation. Anti-Neu T cell immunity was investigated by determining the release of IL-2 and IFN-gamma in T cells supernatant. Survival curves were determined using the Kaplan-Meier method and compared using the log-rank test. Differences in tumor volumes, number of apoptotic cells, titer of the serum, percentage of ADCC were evaluated through a two-tailed Student's t-test. RESULTS: rV-neuT intratumoral vaccination was able to inhibit the growth of SALTO cancer cells in a dose-dependent manner. The anti-Neu serum titer paralleled in vivo antitumor activity of rV-neuT vaccinated mice. rV-neuT immune serum was able to mediate ADCC, inhibition of SALTO cells proliferation, down regulation of the ErbB2/Neu receptor, inhibition of ERK1/2 phosphorylation and induction of apoptosis, thus suggesting potential mechanisms of in vivo tumor growth interference. In addition, spleen T cells of rV-neuT vaccinated mice released IFN-gamma and IL-2 upon in vitro stimulation with several Neu-specific peptides located in the extracellular domain of Neu sequence. CONCLUSIONS: rV-neuT intratumoral vaccination could be employed to induce an efficient antitumor response and reject transplanted salivary gland tumors. Our findings may have important implications for the design of cancer vaccine protocols for the treatment of salivary gland tumors and other accessible tumors using intratumoral injection of recombinant vaccinia virus.

Nutritional stress and arginine auxotrophy confer high sensitivity to chloroquine toxicity in mesothelioma cells.

The correlation between cell sensitivity to autophagy inhibitors, such as chloroquine (CQ), and the expression/activity of molecules involved in the control and execution of autophagy is well documented. However, tumor cells with comparable autophagic potentials may display variable degrees of autophagy addiction, due to the differential expression of molecular determinants, which are still scarcely defined. In this study, we investigated the effects of CQ on growth, death, and autophagic activity of malignant mesothelioma cell lines cultured in standard versus nutritional stress conditions partially mimicking those found in the tumor microenvironment. We report that, in each cell line, the toxic effects of CQ were amplified by nutritional stress and paralleled by autophagy inhibition. Still, the cell lines displayed different levels of sensitivity to CQ toxicity, which did not correlate with their relative degrees of constitutive and nutritional stress-induced autophagy, nor with the relative magnitude of the autophagy inhibition induced by the drug. Thus, we tested the hypothesis that the cell lines' sensitivity to CQ was related to their variable dependence on recycling of intracellular constituents by autophagy. In fact, the cell line with the highest sensitivity to the toxic effects of CQ was auxotrophic for arginine, due to the deficient expression of the enzyme argininosuccinate synthetase (ASS). Furthermore, overexpression of ASS in these cells reduced their sensitivity to CQ toxicity. Based on these results, the assessment of ASS expression in malignant mesothelioma tissues may allow the identification of subgroups of tumors with an increased sensitivity to the toxic effects of this drug.

Caveolin-1 overexpression is associated with simultaneous abnormal expression of the E-cadherin/α-ß catenins complex and multiple ErbB receptors and with lymph nodes metastasis in head and neck squamous cell carcinomas.

The presence of lymph node metastases is one of the most important prognostic indicators in head and neck squamous cell carcinomas (HNSCCs). An alteration of the E-cadherin-catenins complex and EGFR is essential for the invasiveness of cancer cells. Caveolin-1, the major structural protein of the caveolae, represents a scaffolding molecule for several signaling proteins including EGFR. Although caveolin-1 has been shown to play a role in inducing the invasive phenotype of cancer cells, its role appears to be cell-type specific and for some tumors it has not been defined yet. In this study we used 57 HNSCC specimens to investigate whether the abnormal expression of caveolin-1 was associated with the derangement of the E-cadherin-catenins complex and with the overexpression of ErbB receptors. We demonstrate that in HNSCCs caveolin-1 overexpression is associated with the simultaneous abnormal expression of at least one member of the E-cadherin/α-ß catenins complex and multiple ErbB receptors as well as with lymph node metastases. We also demonstrate that chronic stimulation of a human hypopharyngeal carcinoma cell line (FaDu) with EGF induced the internalization of ß-catenin and caveolin-1 and their co-localization with EGFR. Moreover, EGF treatment induced an increased physical interaction between EGFR/ß-catenin/caveolin-1 and between E-cadherin/ß-catenin/caveolin-1. These molecular events were associated with an increased directional motility of FaDu cells in vitro. These findings may provide new insight into the biology of HNSCC progression and help to identify subgroups of primary HNSCCs with a more aggressive behavior.

Group B Streptococcus (GBS) disrupts by calpain activation the actin and microtubule cytoskeleton of macrophages.

Group B Streptococcus (GBS) has evolved several strategies to avoid host defences where macrophages are one of main targets. Since pathogens frequently target the cytoskeleton to evade immune defences, we investigated if GBS manipulates macrophage cytoskeleton. GBS-III-COH31 in a time- and infection ratio-dependent manner induces great macrophage cytoskeleton alterations, causing degradation of several structural and regulatory cytoskeletal proteins. GBS ß-haemolysin is involved in cytoskeleton alterations causing plasma membrane permeability defects which allow calcium influx and calpain activation. In fact, cytoskeleton alterations are not induced by GBS-III-COH31 in conditions that suppress ß-haemolysin expression/activity and in presence of dipalmitoylphosphatidylcholine (ß-haemolysin inhibitor). Calpains, particularly m-calpain, are responsible for GBS-III-COH31-induced cytoskeleton disruption. In fact, the calpain inhibitor PD150606, m-calpain small-interfering-RNA and EGTA which inhibit calpain activation prevented cytoskeleton degradation whereas µ-calpain and other protease inhibitors did not. Finally, calpain inhibition strongly increased the number of viable intracellular GBS-III-COH31, showing that cytoskeleton alterations reduced macrophage phagocytosis. Marked macrophage cytoskeleton alterations are also induced by GBS-III-NEM316 and GBS-V-10/84 through ß-haemolysin-mediated plasma membrane permeability defects which allow calpain activation. This study suggests a new GBS strategy to evade macrophage antimicrobial responses based on cytoskeleton disruption by an unusual mechanism mediated by calcium influx and calpain activation.

Spontaneous immunogenicity of ribosomal P0 protein in patients with benign and malignant breast lesions and delay of mammary tumor growth in P0-vaccinated mice.

A common carboxyl-terminal epitope (C-22 P0) of the ribosomal P proteins (P0, P1 and P2) was shown to elicit autoantibodies in systemic lupus erythematosus (SLE) and in head and neck cancer patients. In this report we provide evidence for the in vivo immunogenicity of the P0 protein in breast cancer patients. Using recombinant P proteins, we demonstrated that sera from breast carcinoma patients (8/75) displayed significant reactivity to P0 protein when compared with healthy donor sera (0/45). Four out of the eight sera showed simultaneous reactivity to all P proteins. Breast benign tumor (3/17) and mammary hyperplasia (3/17) patient sera also showed significant reactivity to P proteins, thus suggesting that the occurrence of P protein autoantibodies might reveal mammary cell cycle dysregulation. Patient sera reacting with all P proteins recognized C-22 P0. Anti-P0 autoantibodies did not correlate with prognostic parameters of breast carcinomas. High level expression of C-22 P0 was found in mammary carcinomas compared with normal adjacent epithelium and benign lesions. To determine the antitumor activity of P0 as an immunogen, BALB-neuT transgenic mice displaying age-related breast cancer progression were vaccinated using xenogeneic P0 at the stage of mammary atypical hyperplasia. P0 vaccination significantly delayed the onset of mouse mammary tumors that overexpressed C-22 P0. Sera from P0 vaccinated mice recognized C-22 P0. Evidence for immunity to the P0 protein, its overexpression in carcinomas and its peculiar surface localization on cancer cells, along with its antitumor activity as an immunogen might be relevant for the use of P0 protein in monitoring cancer progression and in planning immunotherapeutic strategies.

Proteasome inhibition by bortezomib parallels a reduction in head and neck cancer cells growth, and an increase in tumor-infiltrating immune cells.

Head and neck cancer (HNC) has frequently an aggressive course for the development of resistance to standard chemotherapy. Thus, the use of innovative therapeutic drugs is being assessed. Bortezomib is a proteasome inhibitor with anticancer effects. In vitro antitumoral activity of Bortezomib was investigated employing human tongue (SCC-15, CAL-27), pharynx (FaDu), salivary gland (A-253) cancer cell lines and a murine cell line (SALTO-5) originated from a salivary gland adenocarcinoma arising in BALB-neuT male mice transgenic for the oncogene neu. Bortezomib inhibited cell proliferation, triggered apoptosis, modulated the expression and activation of pro-survival signaling transduction pathways proteins activated by ErbB receptors and inhibited proteasome activity in vitro. Intraperitoneal administration of Bortezomib delayed tumor growth of SALTO-5 cells transplanted in BALB-neuT mice, protracted mice survival and adjusted tumor microenvironment by increasing tumor-infiltrating immune cells (CD4+ and CD8+ T cells, B lymphocytes, macrophages, and Natural Killer cells) and by decreasing vessels density. In addition, Bortezomib modified the expression of proteasome structural subunits in transplanted SALTO-5 cells. Our findings further support the use of Bortezomib for the treatment of HNC and reveal its ineffectiveness in counteracting the activation of deregulated specific signaling pathways in HNC cell lines when resistance to proteasome inhibition is developed.

Targeting the tumor immune microenvironment with "nutraceuticals": From bench to clinical trials.

The occurrence of immune effector cells in the tissue microenvironment during neoplastic progression is critical in determining tumor growth outcomes. On the other hand, tumors may also avoid immune system-mediated elimination by recruiting immunosuppressive leukocytes and soluble factors, which coordinate a tumor microenvironment that counteracts the efficiency of the antitumor immune response. Checkpoint inhibitor therapy results have indicated a way forward via activation of the immune system against cancer. Widespread evidence has shown that different compounds in foods, when administered as purified substances, can act as immunomodulators in humans and animals. Although there is no universally accepted definition of nutraceuticals, the term identifies a wide category of natural compounds that may impact health and disease statuses and includes purified substances from natural sources, plant extracts, dietary supplements, vitamins, phytonutrients, and various products with combinations of functional ingredients. In this review, we summarize the current knowledge on the immunomodulatory effects of nutraceuticals with a special focus on the cancer microenvironment, highlighting the conceptual benefits or drawbacks and subtle cell-specific effects of nutraceuticals for envisioning future therapies employing nutraceuticals as chemoadjuvants.