Lactobacillus / ROS Cancer Research Results

LA, Lactobacillus: Click to Expand ⟱

Features: Bacteria

Lactobacillus acidophilus: Gram-positive, homofermentative, anaerobic microbe
Lactobacillus johnsonii: probiotic bacteria found in the human body and fermented foods.
Lactobacillus Plantarum: probiotic bacterium that may help with inflammation, blood sugar

Lactobacillus crispatus
Lactobacillus rhamnosus

Lactobacillus — A group of Gram-positive, non-spore-forming, lactic-acid-producing bacteria widely present in fermented foods and in the human gastrointestinal and female reproductive microbiota. Many strains are used as probiotics, but biological and anticancer effects are highly species- and strain-specific rather than properties of the genus as a whole. Formal classification is a live microbial/probiotic modality rather than a conventional small-molecule drug. Common shorthand is Lactobacillus spp. or lactobacilli. Following the 2020 taxonomic revision, several historically named Lactobacillus species were reassigned; for example, Lactobacillus plantarum is now Lactiplantibacillus plantarum and Lactobacillus rhamnosus is now Lacticaseibacillus rhamnosus, whereas L. acidophilus, L. johnsonii, and L. crispatus remain within Lactobacillus. Anticancer evidence is strongest for modulation of the intestinal or cervicovaginal microenvironment and host immunity, with direct tumor-cell effects largely preclinical.

Primary mechanisms (ranked):

Microbiome remodeling and epithelial-barrier support, including competitive exclusion of potentially pathogenic or pro-inflammatory organisms, production of lactic acid and antimicrobial metabolites, and improved tight-junction integrity.
Antitumor immune modulation (strain-dependent), including dendritic-cell regulation, IL-12 signaling, CD8+ T-cell priming and tumor-infiltrating cytotoxic T-cell activity; Lactiplantibacillus plantarum L168-derived indole-3-lactic acid is a well-characterized experimental example.
Suppression of chronic inflammatory signaling, including reduced pro-inflammatory cytokine and NF-κB-associated signaling in selected strains and models.
Direct induction of cancer-cell apoptosis and growth arrest by strain-derived metabolites, cell-free supernatants or bacterial components, with ↑ BAX/caspases and ↓ BCL-2 reported in several colorectal and other cancer models.
Modulation of tumor metabolism and hypoxic signaling, including HIF-1α, GLUT1 and glycolysis-related pathways in selected experimental systems; this is not established as a general Lactobacillus effect.
Cervicovaginal ecological protection, particularly with L. crispatus, where Lactobacillus-dominant microbiota are associated with lower high-risk HPV persistence and cervical dysplasia risk; direct inhibition of HPV E6/E7 and cancer-cell proliferation has also been demonstrated in vitro.

Bioavailability / PK relevance: Classical plasma pharmacokinetics are not applicable to live Lactobacillus probiotics. Relevant exposure depends on viable CFU delivered, strain survival through storage and gastric/bile conditions, delivery site, mucosal adherence, transient colonization, baseline microbiota and production of local metabolites. Systemic bacterial exposure is neither required nor desirable. Some microbial metabolites can enter host circulation, but their exposure differs substantially among strains and individuals.

In-vitro vs systemic exposure relevance: Many anticancer experiments expose cultured tumor cells directly to concentrated bacterial supernatants, extracts, purified metabolites or live organisms. These conditions cannot be equated with plasma concentrations after oral probiotic administration. Effects should therefore be interpreted primarily as local gastrointestinal, mucosal or mechanistic evidence unless corresponding metabolite exposure has been demonstrated in vivo.

Clinical evidence status: Preclinical + small human/RCT adjunct evidence. Multiple randomized studies in colorectal-cancer surgery have reported improvements in intestinal barrier function, microbiota composition, bowel recovery or postoperative infectious complications from probiotic or synbiotic mixtures containing Lactobacillus strains. Human evidence does not establish Lactobacillus as a tumor-eradicating therapy or demonstrate improved cancer-specific survival. It should be considered a strain-specific supportive or investigational adjunct rather than an anticancer treatment. Use of live probiotics warrants caution in severely immunocompromised patients, critically ill patients and patients with central venous catheters because rare Lactobacillus bacteremia or sepsis has been documented.

Lactobacillus Mechanistic Profile

Rank	Pathway / Axis	Cancer Cells	Normal Cells	Primary Effect	Notes / Interpretation
1	Microbiome and epithelial barrier	↓ tumor-supportive dysbiosis indirectly	↑ barrier integrity ↑ microbial homeostasis	Reduces intestinal inflammation, pathogen translocation and disruption of epithelial tight junctions	Strongest clinically relevant mechanism; highly strain- and site-dependent
2	CD8 T-cell antitumor immunity	↓ tumor growth indirectly	↑ dendritic-cell IL-12 ↑ CD8+ T-cell activation	Enhances antitumor immune surveillance	Lactiplantibacillus plantarum L168-derived indole-3-lactic acid promotes IL12a expression and CD8+ T-cell function in colorectal-cancer models
3	Inflammatory signaling	↓ NF-κB-associated survival signaling (strain-dependent)	↓ excessive inflammatory signaling	Reduces tumor-promoting chronic inflammation	Direction varies substantially by species, strain, host tissue and immune context
4	Mitochondrial apoptosis	↑ BAX ↑ CASP3 ↑ CASP9 ↓ BCL-2	↔ or substantially less cytotoxicity in selected models	Promotes intrinsic apoptotic cell death	Mostly demonstrated using bacterial extracts or conditioned media at experimental concentrations
5	Cell cycle and proliferation	↓ proliferation ↑ cell-cycle arrest	↔ (model-dependent)	Limits cancer-cell expansion	Specific molecular targets differ markedly among strains and cancer types
6	HPV oncogenic signaling	↓ HPV E6/E7 ↓ CDK2 ↓ cyclin A ↑ p21	↔ protective cervicovaginal environment	Suppresses HPV-associated cervical cancer-cell proliferation	Reported particularly for supernatants from L. crispatus, L. jensenii and L. gasseri; largely preclinical
7	Cervicovaginal microbial ecology	↓ HPV persistence and carcinogenic environment indirectly	↑ Lactobacillus-dominant low-diversity microbiota	Supports epithelial and microbial homeostasis	L. crispatus is consistently more strongly associated with a favorable cervical environment than L. iners
8	HIF-1α and glucose metabolism	↓ HIF-1α ↓ GLUT1 ↓ glycolytic adaptation (model-dependent)	Not established	May impair hypoxia-associated metabolic adaptation	Reported in limited experimental models and should not be generalized across Lactobacillus strains
9	ROS and redox signaling	↑ or ↓ ROS (context-dependent)	↓ excessive oxidative stress in some inflammatory models	Can participate in apoptosis or tissue protection depending on strain and model	Not a uniform primary Lactobacillus mechanism; avoid assigning a single directional genus-level effect
10	Clinical Translation Constraint	Strain effects cannot be extrapolated to the genus	Rare bacteremia possible in high-risk hosts	Limits translation of experimental anticancer findings	Major constraints include strain identity, CFU viability, transient colonization, baseline microbiome heterogeneity, formulation differences, combined-species clinical trials and rare invasive infection in severely immunocompromised or critically ill patients

ROS, Reactive Oxygen Species: Click to Expand ⟱

Source: HalifaxProj (inhibit)

Type:

Reactive oxygen species (ROS) are highly reactive molecules that contain oxygen and can lead to oxidative stress in cells. They play a dual role in cancer biology, acting as both promoters and suppressors of cancer.
ROS can cause oxidative damage to DNA, leading to mutations that may contribute to cancer initiation and progression. So normally you want to inhibit ROS to prevent cell mutations.
However excessive ROS can induce apoptosis (programmed cell death) in cancer cells, potentially limiting tumor growth. Chemotherapy typically raises ROS.
-mitochondria is the main source of reactive oxygen species (ROS) (and the ETC is heavily related)
ROS Homeostasis in Cancer Cells and Its Potential as a Therapeutic Target

"Reactive oxygen species (ROS) are two electron reduction products of oxygen, including superoxide anion, hydrogen peroxide, hydroxyl radical, lipid peroxides, protein peroxides and peroxides formed in nucleic acids 1. They are maintained in a dynamic balance by a series of reduction-oxidation (redox) reactions in biological systems and act as signaling molecules to drive cellular regulatory pathways."
"During different stages of cancer formation, abnormal ROS levels play paradoxical roles in cell growth and death 8. A physiological concentration of ROS that maintained in equilibrium is necessary for normal cell survival. Ectopic ROS accumulation promotes cell proliferation and consequently induces malignant transformation of normal cells by initiating pathological conversion of physiological signaling networks. Excessive ROS levels lead to cell death by damaging cellular components, including proteins, lipid bilayers, and chromosomes. Therefore, both scavenging abnormally elevated ROS to prevent early neoplasia and facilitating ROS production to specifically kill cancer cells are promising anticancer therapeutic strategies, in spite of their contradictoriness and complexity."
"ROS are the collection of derivatives of molecular oxygen that occur in biology, which can be categorized into two types, free radicals and non-radical species. The non-radical species are hydrogen peroxide (H 2O 2 ), organic hydroperoxides (ROOH), singlet molecular oxygen ( 1 O 2 ), electronically excited carbonyl, ozone (O3 ), hypochlorous acid (HOCl, and hypobromous acid HOBr). Free radical species are super-oxide anion radical (O 2•−), hydroxyl radical (•OH), peroxyl radical (ROO•) and alkoxyl radical (RO•) [130]. Any imbalance of ROS can lead to adverse effects. H2 O 2 and O 2 •− are the main redox signalling agents. The cellular concentration of H2 O 2 is about 10−8 M, which is almost a thousand times more than that of O2 •−".
"Radicals are molecules with an odd number of electrons in the outer shell [393,394]. A pair of radicals can be formed by breaking a chemical bond or electron transfer between two molecules."

Recent investigations have documented that polyphenols with good antioxidant activity may exhibit pro-oxidant activity in the presence of copper ions, which can induce apoptosis in various cancer cell lines but not in normal cells. "We have shown that such cell growth inhibition by polyphenols in cancer cells is reversed by copper-specific sequestering agent neocuproine to a significant extent whereas iron and zinc chelators are relatively ineffective, thus confirming the role of endogenous copper in the cytotoxic action of polyphenols against cancer cells. Therefore, this mechanism of mobilization of endogenous copper." > Ions could be one of the important mechanisms for the cytotoxic action of plant polyphenols against cancer cells and is possibly a common mechanism for all plant polyphenols. In fact, similar results obtained with four different polyphenolic compounds in this study, namely apigenin, luteolin, EGCG, and resveratrol, strengthen this idea.
Interestingly, the normal breast epithelial MCF10A cells have earlier been shown to possess no detectable copper as opposed to breast cancer cells [24], which may explain their resistance to polyphenols apigenin- and luteolin-induced growth inhibition as observed here (Fig. 1). We have earlier proposed [25] that this preferential cytotoxicity of plant polyphenols toward cancer cells is explained by the observation made several years earlier, which showed that copper levels in cancer cells are significantly elevated in various malignancies. Thus, because of higher intracellular copper levels in cancer cells, it may be predicted that the cytotoxic concentrations of polyphenols required would be lower in these cells as compared to normal cells."

Majority of ROS are produced as a by-product of oxidative phosphorylation, high levels of ROS are detected in almost all cancers.
-It is well established that during ER stress, cytosolic calcium released from the ER is taken up by the mitochondrion to stimulate ROS overgeneration and the release of cytochrome c, both of which lead to apoptosis.

Note: Products that may raise ROS can be found using this database, by:
Filtering on the target of ROS, and selecting the Effect Direction of ↑

Targets to raise ROS (to kill cancer cells):
• NADPH oxidases (NOX): NOX enzymes are involved in the production of ROS.
    -Targeting NOX enzymes can increase ROS levels and induce cancer cell death.
    -eNOX2 inhibition leads to a high NADH/NAD⁺ ratio which can lead to increased ROS
• Mitochondrial complex I: Inhibiting can increase ROS production
• P53: Activating p53 can increase ROS levels(by inducing the expression of pro-oxidant genes)
• Nrf2 inhibition: regulates the expression of antioxidant genes. Inhibiting Nrf2 can increase ROS levels
• Glutathione (GSH): an antioxidant. Depleting GSH can increase ROS levels
• Catalase: Catalase converts H2O2 into H2O+O. Inhibiting catalase can increase ROS levels
• SOD1: converts superoxide into hydrogen peroxide. Inhibiting SOD1 can increase ROS levels
• PI3K/AKT pathway: regulates cell survival and metabolism. Inhibiting can increase ROS levels
• HIF-1α inhibition: regulates genes involved in metabolism and angiogenesis. Inhibiting HIF-1α can increase ROS
• Glycolysis: Inhibiting glycolysis can increase ROS levels • Fatty acid oxidation: Cancer cells often rely on fatty acid oxidation for energy production.
-Inhibiting fatty acid oxidation can increase ROS levels
• ER stress: Endoplasmic reticulum (ER) stress can increase ROS levels
• Autophagy: process by which cells recycle damaged organelles and proteins.
-Inhibiting autophagy can increase ROS levels and induce cancer cell death.
• KEAP1/Nrf2 pathway: regulates the expression of antioxidant genes.
    -Inhibiting KEAP1 or activating Nrf2 can increase ROS levels and induce cancer cell death.
• DJ-1: regulates the expression of antioxidant genes. Inhibiting DJ-1 can increase ROS levels
• PARK2: regulates the expression of antioxidant genes. Inhibiting PARK2 can increase ROS levels
• SIRT1 inhibition:regulates the expression of antioxidant genes. Inhibiting SIRT1 can increase ROS levels
• AMPK activation: regulates energy metabolism and can increase ROS levels when activated.
• mTOR inhibition: regulates cell growth and metabolism. Inhibiting mTOR can increase ROS levels
• HSP90 inhibition: regulates protein folding and can increase ROS levels when inhibited.
• Proteasome: degrades damaged proteins. Inhibiting the proteasome can increase ROS levels
• Lipid peroxidation: a process by which lipids are oxidized, leading to the production of ROS.
    -Increasing lipid peroxidation can increase ROS levels
• Ferroptosis: form of cell death that is regulated by iron and lipid peroxidation.
    -Increasing ferroptosis can increase ROS levels
• Mitochondrial permeability transition pore (mPTP): regulates mitochondrial permeability.
    -Opening the mPTP can increase ROS levels
• BCL-2 family proteins: regulate apoptosis and can increase ROS levels when inhibited.
• Caspase-independent cell death: a form of cell death that is regulated by ROS.
    -Increasing caspase-independent cell death can increase ROS levels
• DNA damage response: regulates the repair of DNA damage. Increasing DNA damage can increase ROS
• Epigenetic regulation: process by which gene expression is regulated.
    -Increasing epigenetic regulation can increase ROS levels

-PKM2, but not PKM1, can be inhibited by direct oxidation of cysteine 358 as an adaptive response to increased intracellular reactive oxygen species (ROS)

ProOxidant Strategy:(inhibit the Mevalonate Pathway (likely will also inhibit GPx)
-HydroxyCitrate (HCA) found as supplement online and typically used in a dose of about 1.5g/day or more
-Atorvastatin typically 40-80mg/day, -Dipyridamole typically 200mg 2x/day Combined effect research
-Lycopene typically 100mg/day range (note debatable as it mainly lowers NRF2)

Dual Role of Reactive Oxygen Species and their Application in Cancer Therapy

ROS-Inducing Interventions in Cancer — Canonical + Mechanistic Reference
-generated from AI and Cancer database
ROS rating:  +++ strong | ++ moderate | + weak | ± mixed | 0 none
NRF2:        ↓ suppressed | ↑ activated | ± mixed | 0 none
Conditions:  [D] dose  [Fe] metal  [M] metabolic  [O₂] oxygen
             [L] light [F] formulation [T] tumor-type [C] combination


Item  ROS↑  NRF2  Condition  Mechanism Class  Remarks  

ROS">Piperlongumine
+++  ↓  [D][T]  ROS-dominant
Selective <span class="wphighlight">ROS</span> stressor, Prevents compensatory upregulation of NRF2, ie GSH↓



ROS">Shikonin
+++ ↓/± [D][T] ROS-dominant
<span class="wphighlight">ROS</span> + glycolysis + GPX4 inhibition



ROS">Vitamin K3 (menadione)
+++ ↓ [D] ROS-dominant
Quinone redox cycler; toxicity limits use



ROS">Copper (ionic / nano)
+++ ↓ [Fe][F] ROS-dominant
Fenton-type redox chemistry



ROS">Sodium Selenite
+++ ↓ [D] ROS-dominant
Pro-oxidant, depletes GSH



ROS">Juglone
+++ ↓ [D] ROS-dominant
Strong quinone <span class="wphighlight">ROS</span> chemistry



ROS">Auranofin
+++ ↓ [D] ROS-dominant
TrxR inhibition → redox collapse



ROS">Photodynamic Therapy (PDT)
+++ 0 [L][O₂] ROS-dominant
Singlet oxygen is core cytotoxic mechanism



ROS">Radiotherapy / Radiation
+++ 0 [O₂] ROS-dominant
DNA damage largely via <span class="wphighlight">ROS</span>



ROS">Doxorubicin
+++ ↓ [D] ROS-dominant
Chemo; redox cycling + mitochondrial <span class="wphighlight">ROS</span>



ROS">Cisplatin
++ ↓ [D][T] ROS-dominant
<span class="wphighlight">ROS</span> contributes to DNA/protein damage



ROS">Salinomycin
++ ↓ [D][T] ROS-dominant
<span class="wphighlight">ROS</span>-mediated CSC toxicity



ROS">Artemisinin / DHA
++ ↓ [Fe][T] ROS-dominant
Iron-activated radical generation



ROS">Sulfasalazine
++ ↓ [C][T] ROS-dominant
Ferroptosis; xCT inhibition → lipid <span class="wphighlight">ROS</span>



ROS">FMD / fasting
++ ↓ [M][C][O₂] ROS-dominant
Metabolic stress → mitochondrial <span class="wphighlight">ROS</span>



ROS">Vitamin C (pharmacologic)
++ ↓ [Fe][D] ROS-dominant
Extracellular H₂O₂ at high dose



ROS">Silver nanoparticles
++ ± [F][D] ROS-dominant
<span class="wphighlight">ROS</span> common; selectivity unreliable



ROS">Gambogic acid
++ ↓ [D][T] ROS-dominant
<span class="wphighlight">ROS</span>-mediated apoptosis



ROS">Parthenolide
++ ↓ [D][T] ROS-dominant
<span class="wphighlight">ROS</span> + NF-κB suppression



ROS">Plumbagin
++ ↓ [D] ROS-dominant
Quinone <span class="wphighlight">ROS</span> driver



ROS">Allicin
++ ↓ [D] ROS-dominant
Thiol-reactive oxidative stress



ROS">Ashwagandha (Withaferin A)
++ ↓ [D][T] ROS-dominant
<span class="wphighlight">ROS</span>-mediated apoptosis



ROS">Berberine
++ ↓ [D][M] ROS-dominant
Mitochondrial <span class="wphighlight">ROS</span> induction



ROS">PEITC
++ ↓ [D][C] ROS-dominant
GSH depletion + <span class="wphighlight">ROS</span>



ROS">Methionine restriction
+ ↓ [M][C][T] ROS-secondary
Redox vulnerability increased; <span class="wphighlight">ROS</span> indirect



ROS">DCA
+ ± [M][T] ROS-secondary
<span class="wphighlight">ROS</span> via forced OXPHOS



ROS">Capsaicin
+ ± [D][T] ROS-secondary
Ca²⁺ stress → <span class="wphighlight">ROS</span>



ROS">Galloflavin
+ 0 [D] ROS-secondary
<span class="wphighlight">ROS</span> not primary driver



ROS">Piperine
+ ± [D][F] ROS-secondary
Weak <span class="wphighlight">ROS</span> induction



ROS">Propyl gallate
+ ↓ [D] ROS-secondary
Pro-oxidant at high dose



ROS">Scoulerine
+ ? [D][T] ROS-secondary
Sparse <span class="wphighlight">ROS</span> data



ROS">Thymoquinone
± ± [D][T] Dual redox
Antioxidant ↔ pro-oxidant switch



ROS">Emodin
± ± [D][T] Dual redox
Not cancer-exclusive



ROS">Alpha-lipoic acid (ALA)
± ↑ [D][M] NRF2-dominant
Antioxidant at low dose



ROS">Curcumin
± ↑/↓ [D][F] NRF2-dominant
Hormetic redox behavior



ROS">EGCG
± ↑/↓ [D][O₂] NRF2-dominant
Auto-oxidation artifacts common



ROS">Quercetin
± ↑/↓ [D][Fe] NRF2-dominant
GSH-dependent cycling



ROS">Resveratrol
± ↑ [D][M] NRF2-dominant
<span class="wphighlight">ROS</span> only at high dose



ROS">Sulforaphane
± ↑↑ [D] NRF2-dominant
Strong NRF2 activator



ROS">Lycopene
0 ↑ — Antioxidant
Consistently antioxidant



ROS">Rosmarinic acid
0 ↑ — Antioxidant
Primarily antioxidant



ROS">Citrate
0 0 — Neutral
Metabolic; not a <span class="wphighlight">ROS</span> agent

Scientific Papers found: Click to Expand⟱

8112-

LA,

Metabolomics and proteomics reveal the inhibitory effect of Lactobacillus crispatus on cervical cancer

in-vitro,

Cerv,

SiHa

HO-1↝, ACSL4↝, Ferroptosis↑, T-cadherin↑, ROS↑, lipid-P↑,

Showing Research Papers: 1 to 1 of 1

* indicates research on normal cells as opposed to diseased cells
Total Research Paper Matches: 1

Pathway results for Effect on Cancer / Diseased Cells:

Migration(tgid=13) ⓘ

T-cadherin↑, 1,
Total Targets: 7

Pathway results for Effect on Normal Cells:

Total Targets: 0

Scientific Paper Hit Count for: ROS, Reactive Oxygen Species

Query results interpretion may depend on "conditions" listed in the research papers.
Such Conditions may include : 
  -low or high Dose
  -format for product, such as nano of lipid formations
  -different cell line effects
  -synergies with other products 
  -if effect was for normal or cancerous cells

Filter Conditions: Pro/AntiFlg:%  IllCat:%  CanType:%  Cells:%  prod#:108  Target#:275  State#:%  Dir#:2
  wNotes=0  sortOrder:rid,rpid

Lactobacillus / ROS Cancer Research Results

Lactobacillus Mechanistic Profile

Pathway results for Effect on Cancer / Diseased Cells:

Redox & Oxidative Stress(tgid=1) ⓘ

Core Metabolism/Glycolysis(tgid=4) ⓘ

Cell Death(tgid=5) ⓘ

Migration(tgid=13) ⓘ

Pathway results for Effect on Normal Cells:

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