Postbiotics in oncology: science or science fiction?

Abstract

The gut microbiome has been increasingly understood to play a critical role in carcinogenesis and cancer disease progression. The most recent research advancements have shown that different tools of microbiota manipulation contribute to gut microbiome–immune–oncology axis modulation, offering exciting opportunities for targeted interventions aimed at improving the efficacy of established anti-cancer therapy. Postbiotics are a new entry among the biotics showing beneficial effects on human health while not requiring living cells to obtain the health effect and therefore not subjected to food safety rules for live microorganisms. Postbiotics are recently defined as the “preparation of inanimate microorganisms and/or their components that confers a health benefit on the host” and have gradually become the focus of the scientific community. Since the beginning of research on this topic, numerous studies about postbiotics have been proven to strengthen the gut barrier, reduce inflammation, and promote antimicrobial activity. However, research on the potential application of cancer therapy is still at the early stages of its efforts to uncover all the secrets surrounding postbiotics. This review aims to increase our understanding of the anti-cancer effect of postbiotics throughout a “bibliographic journey” on the biological activity of their components, including exopolysaccharides, cell wall fragments, tryptophan metabolites, enzymes, bacterial lysates, extracellular vesicles, and short-chain fatty acids, highlighting their perspective as a new supportive therapeutic method of treatment and identifying the literature gaps where further research is needed.

The Most Recent Insights into the Roots of Gastric Cancer

“…Postbiotics are defined as compounds of inanimate microorganisms, either combined or not with their components, which were proven to have a benefit for the host's wellbeing, with recent evidence also suggesting their role in cancer patients [13]. Thus, exopolysaccharides, biopolymers that are released from a different type of bacteria, were suggested to have anti-proliferative effects on different cancer cells or induced apoptosis, making them useful in patients with colorectal cancer or hepatocellular carcinoma [13,14].…”

“…Postbiotics are defined as compounds of inanimate microorganisms, either combined or not with their components, which were proven to have a benefit for the host's wellbeing, with recent evidence also suggesting their role in cancer patients [13]. Thus, exopolysaccharides, biopolymers that are released from a different type of bacteria, were suggested to have anti-proliferative effects on different cancer cells or induced apoptosis, making them useful in patients with colorectal cancer or hepatocellular carcinoma [13,14]. Moreover, bacterial cell fragments such as H. pylori lipopolysaccharide were also indicated to be involved in carcinogenesis, but their promoting or suppressing effects depend on the type of cancer, the applied substance, the cell line stage and the invasiveness [13,15].…”

“…Thus, exopolysaccharides, biopolymers that are released from a different type of bacteria, were suggested to have anti-proliferative effects on different cancer cells or induced apoptosis, making them useful in patients with colorectal cancer or hepatocellular carcinoma [13,14]. Moreover, bacterial cell fragments such as H. pylori lipopolysaccharide were also indicated to be involved in carcinogenesis, but their promoting or suppressing effects depend on the type of cancer, the applied substance, the cell line stage and the invasiveness [13,15]. The role of other bacterial components, such as tryptophan metabolites, extracellular vesicles and short-chain fatty acids, were also suggested to play an active role in carcinogenesis due to their anti-tumor properties [13], but their precise role remains to be established in future studies.…”

“…Moreover, bacterial cell fragments such as H. pylori lipopolysaccharide were also indicated to be involved in carcinogenesis, but their promoting or suppressing effects depend on the type of cancer, the applied substance, the cell line stage and the invasiveness [13,15]. The role of other bacterial components, such as tryptophan metabolites, extracellular vesicles and short-chain fatty acids, were also suggested to play an active role in carcinogenesis due to their anti-tumor properties [13], but their precise role remains to be established in future studies. The role of microbiota and their modulation in promoting or suppressing carcinogenesis was also sustained by the review of Sepich-Poore et al [16].…”

Metabolite profiling and bioactivity guided fractionation of Lactobacillaceae and rice bran postbiotics for antimicrobial-resistant Salmonella Typhimurium growth suppression

“…Postbiotics have been explored for their roles in immune modulation, as antioxidants, chemopreventive agents, and antimicrobial adjuncts and alternatives ( Kumbhare et al, 2023 ). Specifically, postbiotics, prepared with lactic acid bacteria, a diverse group of probiotic strains native to human and animal microbiotas, have been increasingly explored for their roles in antimicrobial activity, including as anti-biofilm agents for interference with quorum sensing, for enhancing the growth of other beneficial microbial symbionts, as applications to food products or used, and in animal production systems to attenuate antimicrobial use ( Ali et al, 2023 ; Chuah et al, 2023 ; Kudra et al, 2023 ; Kumbhare et al, 2023 ; Penchuk et al, 2023 ; Sepordeh et al, 2023 ; Sharafi et al, 2023 ; Tong et al, 2023 ). Across postbiotic studies, there remains a knowledge gap in understanding postbiotic mechanisms of action, including incomplete characterization of the bioactive small molecules driving these diverse functions ( Kumbhare et al, 2023 ).…”