Anti-Cancer Effects of Lactobacillus plantarum L-14 Cell-Free Extract on Human Malignant Melanoma A375 Cells

Limosilactobacillus fermentum role in combination with human mesenchymal stem cell-derived secretome: A novel approach to alleviate inflammation in NASH pathogenesis

BACKGROUND

Nonalcoholic steatohepatitis (NASH) is caused by the accumulation of excess fat in the liver, chronic inflammation, and cell death. The role of the secretome derived from Wharton's jelly and mesenchymal stem cells (WJ-MSC) in reducing inflammation and apoptosis has been investigated in several studies. Also, the strain Limosilactobacillus fermentum (L‌.‌fermentum) was identified as an antimicrobial and antioxidant probiotic. This study looked into the role of a combination of secretome and L.fermentum on cellular stress, apoptosis, and inflammation-related pathways in an NASH in-vitro model.

METHODS

Oil Red O staining confirmed the NASH model was induced using oleic acid and palmitic acid. Then, the 3 different groups were treated with two concentrations of WJ-MSCs-derived secretome, cell-free extract (CFE) of L.fermentum, and their combination. Oxidative stress was evaluated, and western blotting was used to identify the protein. Gene expression and protein quantity were assessed using real-time PCR and ELISA.

RESULT

The analysis revealed the secretome, L.fermentum, and their combination decreased oxidative stress. Additionally, the low levels of Caspase 3 and 9 led to a reduction in apoptosis. The combined treatment significantly impacted inflammation by increasing IL-10 and decreasing IL-6. The expression of STAT3 was also confirmed to be reduced using western blotting. Despite the significant modulation of TNF-alpha and STAT3 by L. fermentum at a high dose, the combined approach led to enhanced performance and restored the cell proliferation.

CONCLUSION

This enhancement has the potential to substantially influence the treatment of NASH disease by impacting inflammation, apoptosis, and oxidative stress, thereby revealing therapeutic potential for NASH disease.

Living therapeutics: Precision diagnosis and therapy with engineered bacteria

Bacteria-based therapy has emerged as a promising strategy for cancer treatment, offering the potential for targeted tumor delivery, immune activation, and modulation of the tumor microenvironment. However, the unpredictable behavior, safety concerns, and limited efficacy of wild-type bacteria pose significant challenges to their clinical translation. Recent advancements in synthetic biology and chemical engineering have enabled the development of precisely engineered bacterial platforms with enhanced controllability, targeted delivery, and reduced toxicity. This review summarize the current progress of engineered bacteria in cancer therapy. We first introduce the theoretical underpinnings and key advantages of bacterial therapies in cancer. Subsequently, we delve into the applications of genetic engineering and chemical modification techniques to enhance their therapeutic potential. Finally, we address critical challenges and future prospects, with a focus on improving safety and efficacy. This review aims to stimulate further research and provide valuable insights into the development of engineered bacterial therapies for precision oncology.

Acetamiprid-induced pulmonary toxicity via oxidative stress, epithelial-mesenchymal transition, apoptosis, and extracellular matrix accumulation in human lung epithelial cells and fibroblasts: Protective role of heat-killed Lactobacilli

Acetamiprid (ACE) is a neonicotinoid insecticide with widespread global application, resulting in persistent human exposure. The current research examined the toxicological implications of ACE exposure on human lung fibroblasts (MRC-5 cells) and bronchial epithelial cells (BEAS-2B cells). The following implications were explored: oxidative stress, epithelial-mesenchymal transition, apoptosis, cellular proliferation, and extracellular matrix accumulation. The prospective protective properties of heat-killed Lactobacillus fermentum and Lactobacillus delbrueckii (HKL) were further studied. The 14-day exposure to ACE at 4 μM triggered oxidative stress and inflammation. ACE promoted epithelial-mesenchymal transition, as evidenced by the decline of protein and mRNA abundances of E-cadherin alongside increased protein and mRNA quantities of α-SMA and N-cadherin in BEAS-2B cells. Additionally, it elicited apoptosis in BEAS-2B cells and stimulated the cellular growth of MRC-5 cells. The TGF-β1/Smad pathway was activated upon ACE exposure, leading to the accumulation of extracellular matrix. HKL demonstrated antioxidant, anti-apoptotic, anti-proliferative, and anti-fibrotic properties, mitigating ACE-induced toxicity. Our findings delineate the molecular mechanisms underlying epithelial-mesenchymal transition, inflammation, oxidative stress, and extracellular matrix accumulation in ACE-induced pulmonary fibrosis, which provides new insights into pulmonary injury. Additionally, this investigation would offer us an approach to mitigate lung deterioration induced by ACE through utilizing heat-killed probiotic supplementation.

Bacterial oncolytic therapy as a novel approach for cancer treatment in humans

Cancer is the leading cause of death worldwide. Conventional cancer therapies, such as chemotherapy, radiation therapy, and immunotherapy often face certain limitations in treating cancer, such as toxicity, resistance, and ineffectiveness against different cancer types. Therefore, there is an urgent need for alternative treatment strategies. One emerging area of interest is the use of bacterial oncolytic therapy. It employs the natural properties of bacteria to target and destroy cancer cells. Both natural and genetically modified bacterial strains have shown potential to target the hypoxic regions of tumors, which are often resistant to conventional treatments. These bacteria also produce therapeutic molecules that induce cancer cell death. Furthermore, they can stimulate immune responses against tumors, making them helpful in developing cancer vaccines and exploiting antitumor bacterial metabolites. The versatility of bacterial oncolytic therapy extends beyond direct tumor targeting. It can be combined with conventional methods to enhance overall treatment efficacy. Moreover, bacteria can also serve as delivery vehicles for anticancer drugs, ensuring more precise targeting and reduced side effects. Different bacterial genera, such as Salmonella, Clostridium, Bifidobacterium, and Listeria, have demonstrated significant anticancer potential. This review aims to provide a comprehensive overview of bacterial oncolytic therapy, exploring its various applications and potential in conjunction with traditional cancer treatments.

Probiotic Potential and Enhanced Adhesion of Fermented Foods-Isolated Lactic Acid Bacteria to Intestinal Epithelial Caco-2 and HT-29 Cells

This study evaluated the probiotic potential of lactic acid bacteria (LAB) isolated from fermented milk and soymilk products purchased from local markets. The LAB strains were assessed for acid and bile resistance, antibiotic resistance, and adhesion to human intestinal epithelial models. Streptococcus thermophilus (JAMI_LB_02) and Lactiplantibacillus plantarum (JAMI_LB_05) showed the highest survival rates in artificial gastric and bile juices, at 87.17 ± 0.02% and 96.71 ± 4.10%, respectively, with all strains (except JAMI_LB_03) demonstrating antibiotic resistance. Adhesion ability indicated the superior performance of JAMI_LB_02 and JAMI_LB_05 compared to standard strains. JAMI_LB_02 adhered to Caco-2 cells at 2.10 ± 0.94% and to HT-29 cells at 3.32 ± 0.38%, exceeding standard strains (1.06 ± 0.13% and 1.89 ± 0.58%). JAMI_LB_05 achieved the highest rates at 5.62 ± 1.33% on Caco-2 and 5.76 ± 0.46% on HT-29 cells. Their combination (JAMI_LB_02 + JAMI_LB_05) significantly enhanced adhesion to 18.57 ± 5.49% on Caco-2 and 21.67 ± 8.19% on HT-29 cells, demonstrating strong synergy. These findings highlight the probiotic potential of the isolated LAB strains, particularly in mixed formulations, which may improve intestinal survival, adaptability, and efficacy. Further in vivo studies are warranted to validate their clinical applications and optimize strain combinations for human health benefits.

Advances in Microbiome-Based Therapeutics for Dermatological Disorders: Current Insights and Future Directions

The human skin hosts an estimated 1000 bacterial species that are essential for maintaining skin health. Extensive clinical and preclinical studies have established the significant role of the skin microbiome in dermatological disorders such as atopic dermatitis, psoriasis, diabetic foot ulcers, hidradenitis suppurativa and skin cancers. In these conditions, the skin microbiome is not only altered but, in some cases, implicated in disease pathophysiology. Microbiome-based therapies (MBTs) represent an emerging category of live biotherapeutic products with tremendous potential as a novel intervention platform for skin diseases. Beyond using established wild-type strains native to the skin, these therapies can be enhanced to express targeted therapeutic molecules, offering more tailored treatment approaches. This review explores the role of the skin microbiome in various common skin disorders, with a particular focus on the development and therapeutic potential of MBTs for treating these conditions.

Lactiplantibacillus plantarum inhibited the growth of primary liver cancer by inducing early apoptosis and senescence, in vitro

Primary liver cancer (PLC), comprising hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA), is a severe form of cancer associated with a high mortality and morbidity rate and increasing incidence worldwide. Current treatment options are limited and chemotherapeutics demonstrate strong side effects. New therapies are highly required. Lactobacilli represent the most diverse lactic acid-producing bacteria group and a prominent example of probiotics. Several studies have highlighted the anticancer efficacy of probiotics, especially of Lactiplantibacillus plantarum. However, there are limited studies on its activity on two PLC types, hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA). This study evaluated the inhibitory mechanism and properties of L. plantarum ONU 12 (Lp 12) and L. plantarum ONU 355 (Lp 355), isolated from grapes in Ukraine and France, in murine PLC cell lines, in vitro. Strain Lacticaseibacillus casei ATCC 393 (Lc 393) has been taken for a direct comparison, as the most studied probiotic strain. The three Lactobacillus species were used in three forms: as live and heat-killed suspensions, and as sonicated extracts, and tested either as a monotherapy or in combination with standard chemotherapeutics (sorafenib for HCC and gemcitabine for CCA). Cell proliferation and viability were assessed via crystal violet staining assay and cell counting kit-8 assay. The induction of senescence was investigated by senescence-associated β-galactosidase assay. Fluorescence-activated cell sorting analysis was used to determine the apoptotic mechanism behind the inhibitory property of lactobacilli. The results showed that the live suspensions and sonicated extracts of Lp 12, Lp 355, and Lc 393 demonstrated inhibitory properties in CCA and HCC cells after 48 h of incubation. In combinations with standard chemotherapeutics, lactobacilli treatments have shown strong synergistic effects. The combination therapy allowed to reduce the chemotherapeutic doses of gemcitabine from 50 μM to 0.1 and 0.05 μM and sorafenib from 13.8 μM to 6.9 and 3.45 μM. Successful treatment regimes induced early apoptosis and cellular senescence in PLC, as the mechanism of inhibition. Heat-killed suspensions showed no inhibitory effect in none of the cell lines. Both strains, Lp 12 and Lp 355, showed successful results and need further testing in vivo, using autochthonous HCC and CCA models.

Exploring Anticancer Potential of Lactobacillus Strains: Insights into Cytotoxicity and Apoptotic Mechanisms on HCT 115 Cancer Cells

Introduction

This study aims to systematically assess the anticancer potential of distinct Lactobacillus strains on Human Colorectal Tumor (HCT) 115 cancer cells, with a primary focus on the apoptotic mechanisms involved. Lactobacillus strains were isolated from sheep milk and underwent a meticulous microbial isolation process. Previous research indicates that certain probiotic bacteria, including Lactobacillus species, may exhibit anticancer properties through mechanisms such as apoptosis induction. However, there is limited understanding of how different Lactobacillus strains exert these effects on cancer cells and the underlying molecular pathways involved.

Methods

Cytotoxicity was evaluated through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays and exposure durations of Lactobacillus cell-free lyophilized filtrates. Additional apoptotic features were characterized using 4.6-diamidino-2-phenylindole (DAPI) analysis for nuclear fragmentation and Annexin V/PI analysis for apoptosis quantification. Genetic analysis explored the modulation of apoptotic proteins (Bax and Bcl2) in response to Lactobacillus treatment. Whole-genome sequencing (WGS) was performed to understand the genetic makeup of the Lactobacillus strains used in the study.

Results

The study demonstrated a significant reduction in HCT 115 cell viability, particularly with L. plantarum, as evidenced by Sulforhodamine B (SRB) and MTT assays. DAPI analysis revealed nuclear fragmentation, emphasizing an apoptotic cell death mechanism. Annexin V/PI analysis supported this, showing a higher percentage of early and late apoptosis in L. plantarum-treated cells. Genetic analysis uncovered up-regulation of pro-apoptotic protein Bax and down-regulation of anti-apoptotic protein Bcl2 in response to Lactobacillus treatment. WGS study revealed a strain reported to NCBI PRJNA439183.

Discussion

L. plantarum emerged as a potent antiproliferative agent against HCT 115 cancer cells, inducing apoptosis through intricate molecular mechanisms. This study underscores the scientific basis for L. plantarum's potential role in cancer therapeutics, highlighting its impact on antiproliferation, adhesion, and gene-protein regulation. Further research is warranted to elucidate the specific molecular pathways involved and to evaluate the therapeutic potential of L. plantarum in preclinical and clinical settings.

Appraisal of postbiotics in cancer therapy

Cancer remains a multifactorial disease with an increased mortality rate around the world for the past several decades. Despite advancements in treatment strategies, lower survival rates, drug-associated side effects, and drug resistance create a need for novel anticancer agents. Ample evidence shows that imbalances in the gut microbiota are associated with the formation of cancer and its progression. Altering the gut microbiota via probiotics and their metabolites has gained attention among the research community as an alternative therapy to treat cancer. Probiotics exhibit health benefits as well as modulate the immunological and cellular responses in the host. Apart from probiotics, their secreted products like bacteriocins, exopolysaccharides, short-chain fatty acids, conjugated linoleic acid, peptidoglycan, and other metabolites are found to possess anticancer activity. The beneficiary role of these postbiotic compounds is widely studied for characterizing their mechanism and mode of action that reduces cancer growth. The present review mainly focuses on the postbiotic components that are employed against cancer with their reported mechanism of action. It also describes recent research works carried out so far with specific strain and anticancer activity of derived compounds both in vitro and in vivo, validating that the probiotic approach would pave an alternative way to reduce the burden of cancer.

Lactiplantibacillus plantarum exerts anticancer effects and increase the chemosensitivity of 5-fluorouracil against oral cancer cells in vitro

Introduction

Probiotics are used to provide health benefits and can improve the immune response. They can also target cancer cells directly with anticancer effects through various mechanisms. In this study, Lactiplantibacillus plantarum (basonym: Lactobacillus plantarum) strain MCC 3016 and its postbiotic metabolites/cell free supernatant (CFS) were used against Cal27 oral cancer cells in vitro.

Methods

Standard assays were employed to investigate the effect of Lpb. plantarum on cell viability, proliferation, migration, and clonogenicity of Cal27 cells. The mechanism of action was assessed by measuring the levels of reactive oxygen species (ROS), interleukins (IL)-6 and IL-8, tumor necrosis factor-α (TNF-α), as well as the expression of Ki67, vascular endothelial growth factor (VEGF), p53 and caspase-3. Further, the effect of Lpb. plantarum and its CFS on the cytotoxicity of chemotherapy drug 5-fluorouracil (5-FU) was evaluated using cell viability assays.

Results

Cal27 cells treated with Lpb. plantarum and its CFS showed a significant decrease (P < 0.01) in cell viability, proliferation, migration, and clonogenicity, along with increased levels of ROS and induced apoptosis. It significantly reduced IL-6, IL-8, TNF-α, and VEGF levels and upregulated p53 and caspase-3 expression. The postbiotic metabolites also showed similar effects on Cal27 cells. Furthermore, the cytotoxic effect of 5-FU on Cal27 cells was enhanced by Lpb. plantarum and its CFS treatment.

Conclusion

Lpb. plantarum MCC 3016 and its postbiotic metabolites exhibited promising anticancer effects on oral cancer cells and improved drug efficacy, demonstrating their potential therapeutic value in oral cancer therapy.

Lactiplantibacillus plantarum Induces Apoptosis in Melanoma and Breast Cancer Cells

Despite the notable advancements witnessed in the past decade in medical and health research domain, cancer remains a prominent global cause of mortality. Moreover, the conventional treatments employed to combat this disease have been found to considerably compromise the quality of life experienced by patients due to its severe side effects. Recent in vitro studies revealed encouraging findings on the potential beneficial effects of probiotics as adjuvants of anticancer therapy, and even as possible agents for the prevention and treatment of various types of malignancies. From this standpoint, the primary objective of this work was to investigate the anticancer properties of Lactiplantibacillus plantarum (LP) and elucidate its underlying mechanism of action. In order to investigate this matter, several doses of LP (ranging from 105 to 1010 CFU/mL) were examined in relation to melanoma cancer cell lines (A375) and breast cancer cell line (MCF-7). The cell viability findings, which were substantiated by morphological investigations and annexin V/PI assay, indicated that LP exerted inhibitory effects on cellular activity and triggered apoptosis. Additionally, upon further investigation into its mechanism, it was observed through the apoptosis assay and Western blot analysis that the administration of LP resulted in an elevation of pro-apoptotic BAX protein levels and an upregulation of cleaved poly-ADP-ribose polymerase (PARP) protein expression. Conversely, the levels of anti-apoptotic Bcl-2 protein were found to decrease in the A375 and MCF-7 cell lines. These findings provide insight into the pro-apoptotic mechanism of action of LP in these specific cell lines.

Carbon dots labeled Lactiplantibacillus plantarum: a fluorescent multifunctional biocarrier for anticancer drug delivery

A carbon dots (CDs)-biolabeled heat-inactivated Lactiplantibacillus plantarum (HILP) hybrid was investigated as a multifunctional probiotic drug carrier with bioimaging properties using prodigiosin (PG) as anticancer agent. HILP, CDs and PG were prepared and characterized using standard methods. CDs-labeled HILP (CDs/HILP) and PG loaded CDs/HILP were characterized by transmission electron microscopy (TEM), laser scanning confocal microscopy (LSCM) and for entrapment efficiency (EE%) of CDs and PG, respectively. PG-CDs/HILP was examined for stability and PG release. the anticancer activity of PG-CDs/HILP was assessed using different methods. CDs imparted green fluorescence to HILP cells and induced their aggregation. HILP internalized CDs via membrane proteins, forming a biostructure with retained fluorescence in PBS for 3 months at 4°C. Loading PG into CDs/HILP generated a stable green/red bicolor fluorescent combination permitting tracking of both drug carrier and cargo. Cytotoxicity assay using Caco-2 and A549 cells revealed enhanced PG activity by CDs/HILP. LCSM imaging of PG-CDs/HILP-treated Caco-2 cells demonstrated improved cytoplasmic and nuclear distribution of PG and nuclear delivery of CDs. CDs/HILP promoted PG-induced late apoptosis of Caco-2 cells and reduced their migratory ability as affirmed by flow cytometry and scratch assay, respectively. Molecular docking indicated PG interaction with mitogenic molecules involved in cell proliferation and growth regulation. Thus, CDs/HILP offers great promise as an innovative multifunctional nanobiotechnological biocarrier for anticancer drug delivery. This hybrid delivery vehicle merges the physiological activity, cytocompatibility, biotargetability and sustainability of probiotics and the bioimaging and therapeutic potential of CDs.

Whole Genome Sequencing of the Novel Probiotic Strain Lactiplantibacillus plantarum FCa3L

Lactiplantibacillus plantarum is best known for its significant adaptive potential and ability to colonize different ecological niches. Different strains of L. plantarum are widely used as probiotics. To characterize the probiotic potential of the novel L. plantarum FCa3L strain isolated from fermented cabbage, we sequenced its whole genome using the Illumina MiSeq platform. This bacterial isolate had a circular chromosome of 3,365,929 bp with 44.3% GC content and a cyclic phage phiX174 of 5386 bp with 44.7% GC content. The results of in vitro studies showed that FCa3L was comparable with the reference probiotic strain L. plantarum 8PA3 in terms of acid and bile tolerance, adhesiveness, H₂O₂ production, and acidification rate. The strain 8PA3 possessed higher antioxidant activity, while FCa3L demonstrated superior antibacterial properties. The antibiotic resistance of FCa3L was more relevant to the probiotic strain than that of 8PA3, although a number of silent antibiotic resistance genes were identified in its genome. Genomic evidence to support adhesive and antibacterial properties, biosynthesis of bioactive metabolites, and safety of FCa3L was also presented. Thus, this study confirmed the safety and probiotic properties of L. plantarum FCa3L via complete genome and phenotype analysis, suggesting its potential as a probiotic, although further in vivo investigations are still necessary.

Anti-tumor effect of infant-derived Enterococcus via the inhibition of proliferation and inflammation as well as the promotion of apoptosis

Probiotic Enterococcus hirae WEHI01 and Enterococcus faecium WEFA23 from infants were previously found to effectively inhibit the development of melanoma. In this study, their immunomodulatory and antitumor mechanisms were systemically studied. In vitro assay showed that E. hirae WEHI01 and E. faecium WEFA23 achieved biphasic immune regulation, which was revealed by the activation of resting spleen lymphocytes and RAW264.7 macrophages, as well as the anti-inflammation effect when immune cells were treated with LPS. The antitumor effects of E. hirae WEHI01 and E. faecium WEFA23 in vitro and vivo were then investigated. CCK8 and the cell scratch assay showed that the conditioned media, which were co-incubated with Enterococcus and spleen lymphocytes, significantly inhibited the proliferation and migration of B16F10, HepG-2 and HT-29 cells. The results of the tumor-bearing mice model experiment showed that E. faecium WEFA23 inhibition of the growth of tumors in mice, and the anti-tumor mechanism involved three aspects, namely tumor proliferation (decreasing expressions of LDHA, VEGF, MMP2, MMP9 and HIF-1α), inhibition of the pro-inflammation state (decreasing expressions of IL-6, TGF-β and IL-17) and the promotion of apoptosis (increasing expression of Bax/Bcl-2, caspase-3 and p53). The results suggest that the two strains of Enterococcus could be promising candidates for treating melanoma with a highly inhibitory effect.

Bioprotection of Zea mays L. from aflatoxigenic Aspergillus flavus by Loigolactobacillus coryniformis BCH-4

Fungal infection causes deterioration, discoloration, and loss of nutritional values of food products. The use of lactic acid bacteria has diverse applications in agriculture to combat pathogens and to improve the nutritional values of cereal grains. The current research evaluated the potential of Loigolactobacillus coryniformis BCH-4 against aflatoxins producing toxigenic Aspergillus flavus strain. The cell free supernatant (CFS) of Loig. coryniformis was used for the protection of Zea mays L. treated with A. flavus. No fungal growth was observed even after seven days. The FT-IR spectrum of untreated (T1: without any treatment) and treated maize grains (T2: MRS broth + A. flavus; T3: CFS + A. flavus) showed variations in peak intensities of functional group regions of lipids, proteins, and carbohydrates. Total phenolics, flavonoid contents, and antioxidant activity of T3 were significantly improved in comparison with T1 and T2. Aflatoxins were not found in T3 while observed in T2 (AFB1 and AFB2 = 487 and 16 ng/g each). HPLC analysis of CFS showed the presence of chlorogenic acid, p-coumaric acid, 4-hydroxybenzoic acid, caffeic acid, sinapic acid, salicylic acid, and benzoic acid. The presence of these acids in the CFS of Loig. coryniformis cumulatively increased the antioxidant contents and activity of T3 treated maize grains. Besides, CFS of Loig. coryniformis was passed through various treatments (heat, neutral pH, proteolytic enzymes and catalase), to observe its stability. It suggested that the inhibitory potential of CFS against A. flavus was due to the presence of organic acids, proteinaceous compounds and hydrogen peroxide. Conclusively, Loig. coryniformis BCH-4 could be used as a good bioprotecting agent for Zea mays L. by improving its nutritional and antioxidant contents.

Comparative Insights into the Skin Beneficial Properties of Probiotic Lactobacillus Isolates of Skin Origin

In recent times, probiotics have been emerging as one of valuable cosmetic resources. This work was undertaken to evaluate and compare the skin beneficial properties of three Lactobacillus strains, namely, L. plantarum SB202, L. fermentum SB101, and L. paraplantarum SB401, originally isolated from the healthy skins of Koreans. The Lactobacillus isolates were individually grown in MRS broth, and the corresponding cell-free conditioned mediums (CMs), LP202, LF101 and LPP401, were prepared for analyzing diverse cosmetic potentials at a comparative perspective. The superoxide radical and nitrite ion scavenging activities of the CMs were in the orders of LPP401 ≥ LF101 > LP202 and LPP401 > LF101≒LPP202, respectively. They attenuated the lipopolysaccharide-induced reactive oxygen species (ROS) and nitrite ion levels in RAW264.7 murine macrophages both in the order of LPP401 ≥ LF101 > LP202, implying their anti-inflammatory properties. They exhibited antityrosinase activities in the order of LPP401 > LF101 ≥ LP202 and diminished α-melanocyte-stimulating hormone-induced melanin levels in B16F10 melanoma cells in the order of LPP401≒LF101 > LP202, suggesting their skin whitening activities. They enhanced cornfield envelope formation in HaCaT keratinocytes in the order of LPP401 > LF101 > LP202. They inhibited the in vitro hyaluronidase and elastase activities in the orders of LPP401 > LP202 ≥ LF101 and LPP401 ≥ LP202 > LF101, respectively. Their enhancing properties on the synthesis of procollagen type I in normal human dermal fibroblasts were in the order of LF101≒LPP401 > >LP202. The CMs possess various cosmetic characteristics, such as antioxidant, skin whitening, antiaging, barrier improving, and anti-inflammatory activities. LPP401, the CM prepared from L. paraplantarum SB401, has been evaluated to be more desirable cosmetic resource than LP202 and LF101.

The impact of the human microbiome in tumorigenesis, cancer progression, and biotherapeutic development

Background

Cancer impacts millions of lives globally each year, with approximately 10 million cancer-related deaths recorded worldwide in 2020. Mounting research has recognised the human microbiome as a key area of interest in the pathophysiology of various human diseases including cancer tumorigenesis, progression and in disease outcome. It is suggested that approximately 20% of human cancers may be linked to microbes. Certain residents of the human microbiome have been identified as potentially playing a role, including: Helicobacter pylori, Fusobacterium nucleatum, Escherichia coli, Bacteroides fragilis and Porphyromonas gingivalis.

Main body

In this review, we explore the current evidence that indicate a link between the human microbiome and cancer. Microbiome compositional changes have been well documented in cancer patients. Furthermore, pathogenic microbes harbouring specific virulence factors have been implicated in driving the carcinogenic activity of various malignancies including colorectal, gastric and pancreatic cancer. The associated genetic mechanisms with possible roles in cancer will be outlined. It will be indicated which microbes have a potential direct link with cancer cell proliferation, tumorigenesis and disease progression. Recent studies have also linked certain microbial cytotoxins and probiotic strains to cancer cell death, suggesting their potential to target the tumour microenvironment given that cancer cells are integral to its composition. Studies pertaining to such cytotoxic activity have suggested the benefit of microbial therapies in oncological treatment regimes. It is also apparent that bacterial pathogenic protein products encoded for by certain loci may have potential as oncogenic therapeutic targets given their possible role in tumorigenesis.

Conclusion

Research investigating the impact of the human microbiome in cancer has recently gathered pace. Vast amounts of evidence indicate the human microbiome as a potential player in tumorigenesis and progression. Promise in the development of cancer biomarkers and in targeted oncological therapies has also been demonstrated, although more studies are needed. Despite extensive in vitro and in vivo research, clinical studies involving large cohorts of human patients are lacking. The current literature suggests that further intensive research is necessary to validate both the role of the human microbiome in cancer, and the use of microbiome modification in cancer therapy.

Bacterial-Based Cancer Therapy (BBCT): Recent Advances, Current Challenges, and Future Prospects for Cancer Immunotherapy

Currently approximately 10 million people die each year due to cancer, and cancer is the cause of every sixth death worldwide. Tremendous efforts and progress have been made towards finding a cure for cancer. However, numerous challenges have been faced due to adverse effects of chemotherapy, radiotherapy, and alternative cancer therapies, including toxicity to non-cancerous cells, the inability of drugs to reach deep tumor tissue, and the persistent problem of increasing drug resistance in tumor cells. These challenges have increased the demand for the development of alternative approaches with greater selectivity and effectiveness against tumor cells. Cancer immunotherapy has made significant advancements towards eliminating cancer. Our understanding of cancer-directed immune responses and the mechanisms through which immune cells invade tumors have extensively helped us in the development of new therapies. Among immunotherapies, the application of bacteria and bacterial-based products has promising potential to be used as treatments that combat cancer. Bacterial targeting of tumors has been developed as a unique therapeutic option that meets the ongoing challenges of cancer treatment. In comparison with other cancer therapeutics, bacterial-based therapies have capabilities for suppressing cancer. Bacteria are known to accumulate and proliferate in the tumor microenvironment and initiate antitumor immune responses. We are currently well-informed regarding various methods by which bacteria can be manipulated by simple genetic engineering or synthetic bioengineering to induce the production of anti-cancer drugs. Further, bacterial-based cancer therapy (BBCT) can be either used as a monotherapy or in combination with other anticancer therapies for better clinical outcomes. Here, we review recent advances, current challenges, and prospects of bacteria and bacterial products in the development of BBCTs.

Isolation of a Lactobacillus paracasei Strain with Probiotic Attributes from Kefir Grains

Κefir is a rich source of potentially probiotic bacteria. In the present study, firstly, in vitro screening for probiotic characteristics of ten lactic acid bacteria (LAB) isolated from kefir grains was performed. Strain AGR 4 was selected for further studies. Molecular characterization of strain AGR 4, confirmed that AGR 4 belongs to the Lactobacillus paracasei (reclassified to Lacticaseibacillus paracasei subsp. paracasei) species. Further testing revealed that L. paracasei AGR 4 displayed adhesion capacity on human adenocarcinoma cells, HT-29, similar to that of the reference strain, L. casei ATCC 393. In addition, the novel strain exerted significant time- and dose-dependent antiproliferative activity against HT-29 cells and human melanoma cell line, A375, as demonstrated by the sulforhodamine B cytotoxicity assay. Flow cytometry analysis was employed to investigate the mechanism of cellular death; however, it was found that AGR 4 did not act by inducing cell cycle arrest and/or apoptotic cell death. Taken together, these findings promote the probiotic character of the newly isolated strain L. paracasei AGR 4, while further studies are needed for the detailed description of its biological properties.