Vitamin C alone at concentrations up to 57 μM had little effect on cell growth but was toxic at 228 μM (SI Appendix, Fig. S1B), in line with recent studies of high vitamin C concentrations (125–2,000 μM)
In our combination approach, vitamin C increased the effects of low doses of 5-aza-CdR, with 57 μM vitamin C almost doubling the growth inhibition
Using the Chou–Talalay method (28), we found that the two compounds indeed acted synergistically, rather than additively, to inhibit cancer cell growth over the physiological ranges of vitamin C in healthy individuals (26–84 μM)
These results show that targeting the cancer DNA methylome by combining low-dose 5-aza-CdR and vitamin C stimulates the expression of ERVs, the induction of a cell-autonomous immune activation response, and increased apoptosis of cancer cells
The addition of vitamin C to treatment protocols therefore may be a straightforward way to increase the clinical efficacy of such drugs in MDS and leukemia patients
Vitamin C deficiency has been seen previously in patients with multiple types of cancer, including hematological malignancies (35⇓–37). We predict that these patients might receive the most benefits from the combination treatment.
induction of an innate immune response
We therefore measured plasma concentrations of vitamin C in a small number of patients with miscellaneous hematologic malignancies. Strikingly, 58% of patients with hematological neoplasia who were not taking vitamin C supplements had severe vitamin C deficiency (serum concentration <11.4 μM, at which clinical features of scurvy may be manifested) (34), and 33% had vitamin C levels below the normal range
it is possible that vitamin C was oxidized to DHA before it was transported into the cells
Oral administration of vitamin C should be sufficient for the therapeutic strategy, because the concentrations reported in this study would not require i.v. administration.
This statement lacks a basic understanding of vitamin C pharmacokinetics.
Vitamin C is an essential nutrient for humans and has been reported to increase IFN levels in human cells upon virus infection
daily treatment with vitamin C alone at physiological concentrations enhanced the expression of viral-defense genes relative to untreated cells
When combined with low-dose 5-aza-CdR, physiological concentrations of vitamin C synergistically inhibited cancer-cell growth and induced apoptosis. Such synergy was associated with increased ERV expression and dsRNA in treated cells. The mechanism of action differs from that of vitamin C at higher doses, which involves its pro-oxidant activity, including GSH inhibition, to generate reactive oxygen species
This activity has been shown to induce DNA damage and to enhance the sensitivities of myeloid malignancies, multiple myeloma, and cutaneous T-cell lymphoma to arsenic trioxide (41⇓⇓–44). It also can increase chemosensitivity of ovarian cancer cells (27) and selectively kill KRAS or BRAF mutant colorectal cancer cells by inhibiting GAPDH
91% of patients with hematologic malignancies have vitamin C levels that are either low or severly deficient. This study found that vitamin C plus low dose DNA methyltransferase inhibitors have synergistic inhibition of cancer cell proliferation and increased apoptosis. Unfortunately, the authors claimed that oral vitamin C would be sufficient which indicates an incredible lack of understanding of vitamin C pharmacokinetics.
The activation of each of them leads to an inhibition of adenylyl cyclase via G proteins (Gi/o), which in turn activates many metabolic pathways such as mitogen‐activated protein kinase pathway (MAPK), phosphoinositide 3‐kinase pathway (PI3K), cyclooxygenase‐2 pathway (COX‐2), accumulation of ceramide, modulation of protein kinase B (Akt), and ion channels
phytocannabinoids, endocannabinoids, and synthetic cannabinoids
Action of THC in human organism relies on mimicking endogenous agonists of CB receptors—endocannabinoids
The upregulated expression of CB receptors and the elevated levels of endocannabinoids have been observed in a variety of cancer cells (skin, prostate, and colon cancer, hepatocellular carcinoma, endometrial sarcoma, glioblastoma multiforme, meningioma and pituitary adenoma, Hodgkin lymphoma, chemically induced hepatocarcinoma, mantel cell lymphoma)
concentration of endocannabinoids, expression level of their receptors, and the enzymes involved in their metabolism frequently are associated with an aggressiveness of cancer
CB2 receptor contributes to human epidermal growth factor receptor (HER2) pro‐oncogenic signaling and an overexpression of CB2 increases susceptibility for leukemia development after leukemia viral infection
endocannabinoid‐degrading enzymes are upregulated in cancer cell lines and in human tumors
Many cannabinoids, ranging from phytocannabinoids (THC, CBD), endocannabinoids (2‐arachidonoylglycerol, anandamide), to synthetic cannabinoids (JWH‐133, WIN‐55,212‐2), have shown ability to inhibit proliferation, metastasis, and angiogenesis in a variety of models of cancer
Despite some inconsistent data, the main effect of cannabinoids in a tumor is the inhibition of cancer cells’ proliferation and induction of cancer cell death by apoptosis
CB1 and CB2 receptor agonists stimulate apoptotic cell death in glioma cells by induction of de novo synthesis of ceramide, sphingolipid with proapoptotic activity
process of autophagy is upstream of apoptosis in mechanism of cell death induced by cannabinoids
Only abstract available here. Study finds association between high tumor burden, more aggressive disease, and lower NK cell numbers. In addition, inverse assocation with CD16/56 and LDH found. Most likely direct tumor suppression as cause.
Evidence that Estrogen and ER status plays role in hematological cancer. ER-beta agonist inhibited cell growth and induced cell death. Similar to prostate cancer.
n the presence of GLA 5 microg/ml and dexamethasone the degree of apoptosis was 86%
These results demonstrate that GLA induces apoptosis in B-CLL B- and T-cells cells in vitro and that they are more susceptible to GLA-induced apoptosis than normal peripheral blood B- and T-cells.
Interesting study that highlights the complexities between Waldenstrom's Macroglobulinemia and other B-cell lymphoma's. These authors concluded that sFLC's correlated better with treatment outcomes than IgM levels.