The well-known Indian spice turmeric is in the limelight again! Namely, a new study reveals that turmeric extract safely and selectively kills cancer stem cells in a way that chemo and radiation cannot!
This breakthrough new study, which was recently published in the journal Anticancer Research, finds that the primary polyphenol in the ancient herb turmeric, aka curcumin, has the great ability to selectively aim at cancer stem cells, which are the base of tumor malignancy.
This highly-desired function is not at the expense of side effect toxicity: on the contrary little- to-no toxicity on normal stem cells has been detected, which is essential for tissue regeneration and longevity.
The study titled “Curcumin and Cancer Stem Cells: Curcumin Has Asymmetrical Effects on Cancer and Normal Stem Cells” describes the wide range of presently-identified molecular mechanisms by which curcumin ‘attacks’ and Cancer Stem Cells (CSCs), which are ‘subpopulation’ of self-renewing cells within a tumor colony, and which alone are able to produce all the other cells within a tumor, making them the most lethal of all cells within most (if not all) cancers.
Because CSCs are highly resistant to chemotherapy, radiation, and may even be provoked towards increased invasiveness through surgical intervention, they are widely believed to be at the core of tumor recurrence and thus failure of conventional treatment.
The study (source) pinpointed the following 8 molecular mechanisms by which curcumin targets and kills cancer stem cells:
1. Down-regulation of interleukin-6 (IL-6): IL-6 is listed as a cytokine (a potent biomolecule released by the immune system) and modulates both immunity and inflammation. Its over expression has been linked to the progression from inflammation to cancer. Curcumin inhibits IL-6 release, which, in turn, prevents CSC stimulation.
2. Down-regulation of interleukin-8 (IL-8): IL-8, another cytokine, is released after tumor cell death, subsequently stimulating CSCs to regrow the tumor and resist chemotherapy. Curcumin inhibits IL-8 production both directly and indirectly.
3. Down-regulation of interleukin-1 (IL-1): IL-1, a family of cytokines, are involved in response to injury and infection, with IL-1 β playing a key role in cancer cell growth and the stimulation of CSCs. Curcumin inhibits IL-1 both directly and indirectly.
4. Decrease CXCR1 and CXCR2 binding: CXCR1 and CXCR2 are proteins expressed on cells, including CSCs, which respond to the before-mentioned cytokines in a deleterious manner. Curcumin has been found to not only obstruct cytokine release, but their binding to these 2 cellular targets as well.
5. Modulation of the Wnt signaling pathway: The Wnt signaling pathway regulates a wide range of processes in the course of embryonic development, but are also dysregulated in cancer. Curcumin has been found to have a corrective action on Wnt signaling too.
6. Modulation of the Notch Pathway: The Notch signaling pathway, also involved in embryogenesis, plays a key role in regulating cell differentiation, proliferation and programmed cell death (apoptosis) as well as the functioning of normal stem cells. Aberrant Notch signaling has been implicated in a wide variation of cancers. Curcumin has been found to suppress tumor cells along the Notch pathway.
7. Modulation of the Hedgehog Pathways: Another pathway involved in embryogenesis, the Hedgehog pathway, also regulates normal stem cell activity. Abnormal functioning of this pathway is implicated in a wide span of cancers and in the stimulation of CSCs and associated increases in tumor recurrence after conventional treatment. Curcumin has been found to inhibit the Hedgehog pathway through several different mechanisms.
8. Modulation of the FAK/AKT/FOXo3A Pathway: This pathway plays a key role in regulating normal stem cells, with aberrant signaling stimulating CSCs, resulting once again in tumor recurrence and resistance to chemotherapy. Curcumin has been found in multiple studies to destroy CSCs by inhibiting this pathway.
The above-explained 8 patterns show that curcumin exhibits a rather profound level of complexity, simultaneously modulating numerous molecular pathways.
Conventional cytotoxic chemotherapy showed unable of such delicate and “intelligent” behavior, as it preferentially targets fast-replicating cells by damaging their DNA in the vulnerable mitosis stage of cell division, regardless of whether they are benign, healthy or cancerous cells.
On the other hand, curcumin’s selective cytotoxicity targets the most dangerous cells – the cancer stem cells while leaving substantially unharmed the normal cells, as we will see below.
Normal stem cells and curcumin
Normal stem cells (NSCs) are crucial for good health since they are responsible for differentiating into normal cells that are needed to replace sick and damaged ones. If curcumin were to kill normal cells, like radiation and chemotherapy, it would not provide a compelling alternative to these treatments.
The scientific effort exactly elaborated this point: “The safety of curcumin has been long established, as it has been used for centuries as a dietary spice.
The question arises as to why curcumin does not seem to have the same deleterious effects on normal stem cells (NSCs) as it does on CSCs. There are several possible reasons that curcumin has toxic effects on CSCs, while sparing NSCs.”
The study located 3 possible reasons for curcumin’s differential or selective cytotoxicity:
1. Malignant cells ‘take in’ much more curcumin than normal cells.
2. Curcumin alters the microenvironment of cells in such a way that is adverse to CSCs and beneficial to NSCs.
3. Curcumin may not only directly assault CSCs, but may encourage them to differentiate into non-lethal, more benign cells.
This study contributes growing support to the idea that safe, time-tested, natural substances are superior to synthetic ones. Given the evidence that a safe and effective alternative may already exist, chemotherapy, radiation including invasive surgery may no longer be recommended as the first-line standard care for cancer treatment.
In fact, a significant corpus of evidence now targets these treatments in worsening conditions, and, in some individual cases, even in driving cancer stem cells enrichment in tumorous growths.
For instance, radiotherapy has been found to cancer stem cells like properties in breast cancer cells, essentially increasing their malignancy and tumoriogenicity by 30 fold! This can hardly be called progress when one considers the important role that CSCs play in the cell world, especially in contributing to post-treatment secondary cancers.
The healing power of turmeric, including its subcomponents, of course, are not FDA approved drugs, and as a rule the FDA will simply not allow an unapproved substance, be that a natural or a synthetic one, to prevent, treat, diagnosis or cure a disease!
This definitely means that you will not be hearing it offered by an oncologist as an alternative to chemotherapy and radiation any time around now. However, this does not, , mean that it does not work in cancer patients.
In support of this, we have gathered over 1,500 citations from the National Library of Medicine’s bibliographic database MEDLINE, accessible through www.pubmed.gov, showing that curcumin and related turmeric components possess noteworthy anti-cancer activity.
Truth be told, the material is so extensive, with its over 700 possible health benefits, that we believe this plant to embody a form of “intelligence and even compassion.” You can learn more about this supposition here: Turmeric’s Healing Power: A Physical Manifestation of Compassion?
Surely, the point is not to wait so long until one has such a severe and deadly health problem that taking “heroic doses” of spices or herbs like turmeric, garlic, ginger, etc. becomes their focal point in life. It is matters to remember that ancient cultures used spices like turmeric mainly in culinary doses, as part of their daily dietary practices.
These smaller amounts, delivered mainly as whole food extracts, likely constituted effective preventive practices. Perhaps, in order to prevent the need for radical, heroic intervention later in life. If you read our previous articles on turmeric, you will see this point explored from different aspect or in light of a human clinical study.
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Sources and references:
National Library of Medicine
Health Guide: Turmeric
Health Guide: Cancer Research