Human Endogenous Formaldehyde as an Anticancer Metabolite: Its Oxidation Downregulation May Be a Means of Improving Therapy

Malignant cells are characterized by an increased content of endogenous formaldehyde formed as a by-product of biosynthetic processes. Accumulation of formaldehyde in cancer cells is combined with activation of the processes of cellular formaldehyde clearance. These mechanisms include increased ALDH and suppressed ADH5/FDH activity, which oncologists consider poor and favorable prognostic markers, respectively. Here, the sources and regulation of formaldehyde metabolism in cancer cells are reviewed. The authors also analyze the participation of oncoproteins such as fibulins, FGFR1, HER2/neu, FBI-1, and MUC1-C in the control of genes related to formaldehyde metabolism, suggesting the existence of two mutually exclusive processes in cancer cells: 1) production and 2) oxidation and elimination of formaldehyde from the cell. The authors hypothesize that the study of the anticancer properties of disulfiram and alpha lipoic acid - which affect the balance of formaldehyde in the body - may serve as the basis of future anticancer therapy.

[Velcade in multiple myeloma]

AIM

To study efficacy of velcade therapy in patients with progressive or refractory multiple myeloma (MM).

MATERIAL AND METHODS

From April 2005 to November 2006 velcade was used in therapy of 18 patients (11 females and 7 males) with progressive or refractory to prior standard therapy MM course. The patients' age median was 55 years (36 to 76 years). Velcade was injected intravenously on the course days 1, 4, 8 and 11 with interval 10 days between the courses. A total of 77 courses were made (median 4.5).

RESULTS

Overall efficacy was assessed according to EBMT criteria in 16 (68%) patients. Partial remission (PR) was achieved in 9 patients, complete remission (CR)--in 1, minimal response (MR)--in 1 patient. Five patients failed the treatment. In 5 of 11 patients with confirmed efficacy of velcade the drug was used in induction of remission before high-dose chemotherapy (HDC) and autotransplantation of hemopoietic stem cells (HSC), in 3--as monotherapy, in 1--in combination with high-dose dexamethasone, in--with high dose dexamethasone and doxorubicin. Four patients achieved PR, one--MR. HSC were obtained before velcade therapy in one patient, in 4--after its conduction. After HDC there were one CR and 4 PR. Recovery of hemopoiesis after HDC took the same time as after standard induction therapy. In 6 of 11 patients HDC was not performed. Velcade therapy is continued in 2 patients, in 1 case with CR the treatment was stopped. In 3 cases PR for 2 to 6 months was followed by the disease progression.

CONCLUSION

Velcade as a new effective antitumor drug can be used for treatment of progressive and refractory forms of MM.