Curcumin’s anticancer effect: ability to induce apoptosis

Turmeric is a popular Indian spice that may have wonderful health benefits for cancer patients. Curcumin (diferuloylmethane) is its major component; Curcuma longa L., a member of the ginger family has long been treasured for its unique flavor it adds to various dishes. Its anti-cancer effects have been studied for numerous tumor activity including colon cancer, breast cancer [1], lung metastases, and brain tumor [2], and because it may inhibit mTOR pathways (discussed below), it may inhibit the growth of all cancers.

Curcumin’s anticancer effect is attributed to its ability to induce normal, programmed cell death (apoptosis) in cancer cells without cytotoxic effects on healthy cells, which is very attractive to patients and clinicians. If we can understand that cancer, at its heart, is both an apoptotic failure and an increased replication rate, a nutrient that may help stop both is impressive.
Curcumin interferes with NF-κB [3], a powerful inflammatory pathway that has been linked with numerous inflammatory diseases including cancer [4]. NF-κB has been linked to cancer metastasisThe spread of cancer cells from the place where they first formed to another part of the body. In metastasis, cancer cells break away from the original (primary) tumor, travel through the blood or lymph system, and form a new tumor in other organs or tissues of the body. The new, metastatic tumor is the same type of cancer as the primary tumor. For example, if breast cancer spreads to the lung, the cancer cells in the lung are breast cancer cells, not lung cancer cells. which is the primary cause of death in most cancer patients. Curcumin’s ability to limit this and inhibit metastasis is promising.

Curcumin was found to inhibit mTOR complex I, which is a major growth pathway that seems to be up-regulated in those with cancer. [5] Understand, mTOR is very important at different times in life. It is highly active in infants and children, stimulating rapid growth and development necessary for weight gain and cellular replication; it is activated in wound healing, scar formation, and tissue regeneration. It is necessary to support recovery from injury. However, those with a history of cancer or any active growth do not want increased mTOR function.

There exist numerous exogenous sources that can artificially stimulate mTOR function which cancer patients may want to be aware. Diets high in dairy products may up-regulate mTOR as dairy contains hormones and a chemical known as intrinsic growth factor (IGF-1) that helps baby cows quickly expand their mass and grow.

Protein-rich diets and protein powder drinks may also increase mTOR through glutamine, leucine, and arginine. Glutamine both stimulates mTOR directly through the ARF1 pathway and indirectly by regulating cellular uptake of leucine to stimulate mTOR through the RAG pathway. Glutamine also converts to glutamate and this conversion process may be up-regulated should a person have certain genetic defects. Both self-produced as well as exogenous (food-borne) glutamates (MSG) stimulate mTOR function.

Other dietary and environmental concerns exist that increase mTOR. High-fructose corn syrup, pesticides and plastics exposure, and even iron and methylated vitamin supplementation may be a cause. Remember, mTOR stimulates growth and replication of cells, great from growing babies but not for those with cancer. Patients with cancer might best be cautious of environmental exposures that stimulate this pathway.

When we better understand the pathways, what they do and what promotes and inhibits them, we better understand how to help ourselves. The good news is, curcumin may modulate the growth of tumor cells by inhibiting mTOR as well as regulating a multitude of other cell signaling pathways. Curcumin was found to help down-regulate the cell proliferation pathway (cyclin D1, c-myc) and directly stimulate apoptosisA type of cell death in which a series of molecular steps in a cell lead to its death. This is one method the body uses to get rid of unneeded or abnormal cells. The process of apoptosis may be blocked in cancer cells. Also called programmed cell death. (cell death) by up-regulating the caspase activation pathway (caspase-8, 3, 9), tumor suppressor pathway (p53, p21), and death receptor pathway (DR4, DR5), [6-10]. Curcumin is a real hero for all with cancer.

Researchers Epstein and co-workers had a thorough review on in vitro, [7] citing curcumin as, “non-toxic to human subjects at a high oral dose of up to 12 g/day, and it has anti-inflammatory, antioxidant and anti-cancer properties”. Twelve grams per day is a hefty dose and more than most probably will ever need. One might consider consuming 2-6 grams per day spread over the course of the day. One caution might be to watch any reactions to curcumin as some people with poor gut function may have developed antibodies to turmeric. These individuals may be fine consuming the active C3 form of curcumin with no ill effects.

Other studies show that, when curcumin is combined with other nutrients, a synergistic response may result. Adding sulforaphane (from broccoli seed extract), EPA and DHA (from fish oils), Resveratrol, and EGCg from Green Tea Extract may increase curcumin’s effectiveness. [11-15]