Metformin Reduce the Relapse Rate on Patients With B-cell Precursor (Ph+ Negative) Acute Lymphoblastic Leukemia

The MDR (Multidrug-Resistance) Genes are implicated on the resistance of several types of cancer. The most important on leukemia are the ABCB1 and ABCG2- ABCB1 are implicated on resistance and severity on Acute Myeloid Leukemia and pediatric Acute Lymphoblastic Leukemia. Those transporters use ATP for use. Metformin decrease the intracellular ATP (Adenosine triphosphate) reserve the by the activation of AMPK. Recently on MCF7-Adr (Michigan Cancer Foundation 7, breast cancer cell line) cancer cell line, Metformin block the function of the P-glycoprotein by the inhibition of the Nuclear Factor -kappa-B.

The clinical evidence at this moment is limited, based on small clinical trials or observational studies. This study tries to evaluate the effect of the addition of Metformin to a standard chemotherapy regimen on patients who express high levels of expression of mRNA (messenger ribonucleic acid) ABCB1

Experimental protocol

The patients will be stratified on three groups: The high-expression, low expression and absent gene expression according the level mRNA of ABCB1 at diagnostic. The samples are obtained from mononuclear peripheral blood cells

Extraction of total RNA Total RNA was isolated by TRIzol® (Invtirogen Life Technologies) according to the manufacturer´s recomendations described by Chomczynski and Sacchi.

The concentration and purity of total RNA was determined in a UV -vis spectrophotometer (Thermo Scientific , Genesis 10S UV-vis). The integrity of the genetic material was confirmed by 1.5% agarose gel electrophoresis at 70 V for 40 min. The RNA was stored at -80°C until needed.

Synthesis of cDNA Fort he synthesis of c DNA (complementary deoxyribonucleic acid) the amount of RNA used was 2µg for a final volume of 20 µg. The RNA was mixed with 1 µl oligonucleotide 12-18 (INVITROGEN, Carlsbad, CA) and 1 µl de dNTPs (deoxynucleoside triphosphate) 10mM (Applied Biosystems, Roche). After the addition of 4 µl of Buffer 5 X (Tris- HCl (hydrochloric acid) 250mM, KCl (potassium chloride) 375 mM MgCl2 15mM), 2 µl de DTT (dithiothreitol) (0.1M) and wáter, all the mix was incubated at at 37° for two minutes and 1 µl of MMLV(Moloney Murine Leukemia Virus Reverse Transcriptase) Reverse transcriptase- enzyme (200u) (INVITROGEN, Carlsbad, CA) and incubated at 37°C for 50 minutes.

Real-time polymerase chain reaction (qRT-PCR) analysis The mRNA expression levels of the ABCB1 (Hs01069047), and glyceraldehyde 3-phosphate dehydrogenase (GAPDH; Hs00985689) genes were measured using the TaqMan® gene expression assay (Applied Biosystems, Foster City, CA, USA). The GAPDH gene was used as an endogenous control, and each sample was analyzed in triplicate. The relative expression levels were calculated using the 2-ΔΔCtmethod with bone marrow as a calibrator. The high and low expression cut-off points were determined by the mean values observed in healthy donors.

Treatment protocol All the patients recieve an induction remission treatment with an initial pre-induction phase with steroids (prednisone) from day -7 to day -1 (-7 ,-6 = 25mg , -5 , -4 : 50mg , -3, -2: 75mg and on day -1 : 100mg). The induction remission treatment is based on a 28 day treatment with prednisone (60mg/m2),Vincristine (1.5mg/m2 maxium 2mg) and Daunorubicin 60mg/m2 on days +1, +8 and +15. If the patient archive a Complete Remission, continues with a consolidation therapy with sequential blocks of treatment that includes Cytarabine, Etoposide, Methotrexate. If the patient still on remission at the end of consolidation therapy continues on maintenance phase that includes 6-mercaptopurine and a weekly dose of methotrexate for around two years

Response At day 28 of the induction remission treatment, according the result of bone marrow sample the patientes will be declared on remission (less than 5% blast) or refractory (>5% blast cell). If the patient present at any point of treatment an increase on bone marrow blast count the patient is considered on relapse.

Inclusion criteria

• > 18 years
• de novo B-cell precursor Acute Lymphoblastic Leukemia
• candidates to first line treatment protocol
• ECOG (Eastern Cooperative Oncology Group) Scale of Performance Status 1/2
• Informed Consent Form for genetic analysis samples
• Precursor B Cell Acute Lymphoblastic Leukemia

Exclusion criteria

• Diagnose of Acute Myelogenous Leukemia or Biphenotype Leukemia
• Diagnose of type 2 Diabetes Mellitus
• Previous use of Metformin
• Relapsed Acute Leukemia that require treatment protocol to be started
• Intolerance to prednisone
• ECOG Scale of Performance Status 3/4
• T-cell Acute Lymphoblastic Leukemia
• Philadelphia positive Acute Lymphoblastic Leukemia
• Tumor lysis syndrome at diagnose
• Renal Failure (creatinine leve higher than 2mg/dl)
• Several liver damage (>2 levels de upper normal limit of Aspartate transaminase (AST) and alanine transaminase (ALT)
• Metabolic Acidosis or Lactic Acidosis at diagnose
• Central nervous system infiltration at diagnose
• Extramedullary disease (skin, pleura,eye)
• Active GI bleeding