The role of dietary probiotic strains on host anti-cancer immune responses against experimental colon carcinoma was investigated. We have previously shown that Lactobacillus casei administration led to tumor growth suppression in an experimental colon cancer model. Here, we investigated the underlying immune mechanisms involved in this tumor-growth inhibitory effect. BALB/c mice received daily live lactobacilli per os prior to the establishment of a syngeneic subcutaneous CT26 tumor. Tumor volume, cytokine production, T cell differentiation and migration, as well as tumor cell apoptosis were examined to outline potential immunomodulatory effects following L. casei oral intake. Probiotic administration in mice resulted in a significant increase in interferon gamma (IFN-γ), Granzyme B and chemokine production in the tumor tissue as well as enhanced CD8⁺ T cell infiltration, accompanied by a suppression of tumor growth. Cytotoxic activity against cancer cells was enhanced in probiotic-fed compared to control mice, as evidenced by the elevation of apoptotic markers, such as cleaved caspase 3 and poly (ADP-ribose) polymerase 1 (PARP1), in tumor tissue. Oral administration of Lactobacillus casei induced potent Th1 immune responses and cytotoxic T cell infiltration in the tumor tissue of tumor-bearing mice, resulting in tumor growth inhibition. Thus, the microorganism may hold promise as a novel dietary immunoadjuvant in raising protective anti-cancer immune responses.

There is a growing amount of evidence to support the beneficial role of a balanced intestinal microbiota, or distinct members thereof, in the manifestation and progression of malignant tumours, not only in the gastrointestinal tract but also in distant tissues as well. Intriguingly, bacterial species have been demonstrated to be indispensable modulatory agents of widely-used immunotherapeutic or chemotherapeutic regiments. However, the exact contribution of commensal bacteria to immunity, as well as to neoplasia formation and response to treatment, has not been fully elucidated, and most of the current knowledge acquired from animal models has yet to be translated to human subjects. Here, recent advances in understanding the interaction of gut microbes with the immune system and the modulation of protective immune responses to cancer, either naturally or in the context of widely-used treatments, are reviewed, along with the implications of these observations for future therapeutic approaches. In this regard, bacterial species capable of facilitating optimal immune responses against cancer have been surveyed. According to the findings summarized here, we suggest that strategies incorporating probiotic bacteria and/or modulation of the intestinal microbiota can be used as immune adjuvants, aiming to optimize the efficacy of cancer immunotherapies and conventional anti-tumour treatments.

The mosquito-borne zoonotic nematode parasites Dirofilaria immitis and Dirofilaria repens primarily affect dogs. In recent years, their distribution has expanded due to various factors influencing vector-borne pathogens. This study aimed to investigate the comparative prevalence of infection in dogs and humans within a hyperenzootic region of Europe, and to estimate the proportional relationship between infection prevalence in dogs and humans, within the concept of “One Health”. To this end, 604 blood samples from dogs and 625 serum samples from humans living in the Thrace region of northeastern Greece were collected. The dog samples were examined for Dirofilaria spp. microfilariae using Kott’s test and for D. immitis antigen using a commercial serological test. The human sera were analyzed for both parasites by Western blot. The overall prevalence of infection in dogs was 177 (29.3%), with 173 (28.6%) testing positive for D. immitis and 7 (1.2%) for D. repens, including 6 (1%) cases of mixed infection. Specific IgG antibodies were detected in 42 (6.7%) human samples, with 24 (3.8%) positive for D. immitis and 18 (2.9%) for D. repens. The infection proportion in humans was 23.4% of the corresponding canine infections, indicating a high risk of human infection in this hyperenzootic region.

Origanum vulgare ssp. hirtum is an aromatic plant native to various Mediterranean regions and has been traditionally used in folk medicine. This study investigates the chemical composition and the potential antitumor activity of its essential oil in a preclinical model of CT26 colorectal cancer in BALB/c mice. Mice received prophylactic oral administration of the essential oil, and tumor progression, immune modulation, and apoptosis were evaluated. Even treatment with low doses (350 parts per million, ppm in 100 μL final volume) of the essential oil significantly suppressed tumor growth by approximately 44%. This effect correlated with the enhanced expression of antitumorigenic cytokines, including a 2.7-fold increase in type I interferons (IFN), IFN-γ (from 46.5 to 111.9 pg/μL per mg of protein) and tumor necrosis factor alpha (TNF-α) (from 34.5 to 103 pg/μL per mg of protein). Furthermore, the production of granzyme B, a key mediator of cytotoxic immune cell function, was notably increased from 96.1 to 319.6 pg/μL per mg of protein. An elevated activation of caspase 3, a central effector caspase of all apoptotic cascades, was also observed in tumors from oregano-treated mice. These findings suggest that O. vulgare ssp. hirtum essential oil exhibits promising antitumor properties through immune modulation and immunity-mediated apoptosis induction, supporting its potential development as a bioactive compound for cancer prevention or therapy.

The mosquito-borne zoonotic nematode parasites, Dirofilaria immitis and Dirofilaria repens, primarily affect dogs. In recent years, their distribution has expanded due to various factors influencing vector-borne pathogens. This study aimed to investigate the comparative prevalence of infection in dogs and humans within a hyperenzootic region of Europe and to estimate the proportional relationship between infection prevalence in dogs and humans, in the concept of “One Health”. To this end, 604 blood samples from dogs and 625 serum samples from humans living in the Thrace region of northeastern Greece were collected. Dog samples were examined using Kott’s test for Dirofilaria spp. microfilariae and a commercial serological test for D. immitis antigen. Human sera were analysed by western blot for both parasites. The overall prevalence of infection in dogs was 177 (29.3%), with 173 (28.6%) testing positive for D. immitis and 7 (1.3%) for D. repens, including 6 (1%) cases of mixed infection. Specific IgG antibodies were detected in 42 (6.7%) human samples, with 24 (3.8%) positive for D. immitis and 18 (2.9%) for D. repens. The infection proportion in humans was 23.4% of the corresponding canine infection, indicating a high risk of human infection in this hyperenzootic region.