IntroductionNew levels of gene regulation with microRNA (miR) and gene copy number alterations (CNAs) have been identified as playing a role in various cancers. We have previously reported that sporadic breast cancer tissues exhibit significant alteration in H2AX gene copy number. However, how CNA affects gene expression and what is the role of miR, miR-24-2, known to regulate H2AX expression, in the background of the change in copy number, are not known. Further, many miRs, including miR-24-2, are implicated as playing a role in cell proliferation and apoptosis, but their specific target genes and the pathways contributing to them remain unexplored.MethodsChanges in gene copy number and mRNA/miR expression were estimated using real-time polymerase chain reaction assays in two mammalian cell lines, MCF-7 and HeLa, and in a set of sporadic breast cancer tissues. In silico analysis was performed to find the putative target for miR-24-2. MCF-7 cells were transfected with precursor miR-24-2 oligonucleotides, and the gene expression levels of BRCA1, BRCA2, ATM, MDM2, TP53, CHEK2, CYT-C, BCL-2, H2AFX and P21 were examined using TaqMan gene expression assays. Apoptosis was measured by flow cytometric detection using annexin V dye. A luciferase assay was performed to confirm BCL-2 as a valid cellular target of miR-24-2.ResultsIt was observed that H2AX gene expression was negatively correlated with miR-24-2 expression and not in accordance with the gene copy number status, both in cell lines and in sporadic breast tumor tissues. Further, the cells overexpressing miR-24-2 were observed to be hypersensitive to DNA damaging drugs, undergoing apoptotic cell death, suggesting the potentiating effect of mir-24-2-mediated apoptotic induction in human cancer cell lines treated with anticancer drugs. BCL-2 was identified as a novel cellular target of miR-24-2.Conclusionsmir-24-2 is capable of inducing apoptosis by modulating different apoptotic pathways and targeting BCL-2, an antiapoptotic gene. The study suggests that miR-24-2 is more effective in controlling H2AX gene expression, regardless of the change in gene copy number. Further, the study indicates that combination therapy with miR-24-2 along with an anticancer drug such as cisplatin could provide a new avenue in cancer therapy for patients with tumors otherwise resistant to drugs.

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In vitro, high-resolution (1)H and (31)P NMR based qualitative and quantitative analyses of the lipid components of the tissue, serum, and CSF of patients with primary brain tumors were performed. Proton NMR spectra of the lipid extract of serum (blood specimen collected before the surgical procedure) and surgically discarded tissue showed that the total cholesterol (T.CHOL) and choline containing phospholipids (PL) were significantly higher in quantity in medulloblastoma and glioblastoma multiforme as compared to normal subjects. Serum lipid extracts of grade II/ III gliomas showed a higher quantity of PL than normal subjects. Cholesterol esters (CHOLest) were detectable in the tissue lipid extract of the patients with tumors and absent in normal tissue. There was a reduction in the quantity of CHOLest in the serum lipid extract of the tumor patients as compared to normal subjects. Ratio of PL to T.CHOL in serum lipid extract showed a significant difference between different grades of tumors versus normal subjects, while, a significant difference was observed only in medulloblastoma versus normal subjects in tissue lipid extract. Ratio of CHOL to CHOLest distinguishes the different grades of tumors versus normal subjects as well as between different grades of tumors (except medulloblastoma versus glioblastoma). The ratio of the Ph (total phospholipids except phosphatidylcholine) to PC (phosphatidylcholine) in (31)P NMR based study showed a significant difference in all grades of tumors (except medulloblastoma) in normal subjects in tissue lipid extract as well as between different grades of tumors. Medulloblastoma could be differentiated from glioblastoma as well as from normal subjects in serum lipid extract by the ratio of the Ph to PC. Proton NMR spectra of the lipid extract of CSF showed that the CHOL, CHOLest, and PL were present in the patients with tumors, although these were absent in the patients with meningitis, motor neuron disease, and mitochondrial myopathies as well as in normal subjects. PL and T.CHOL provided discrimination between different grades of tumors (except glioblastoma versus medulloblastoma) in the lipid extract of the CSF. This study suggests the role of lipid estimation in CSF and serum as a complementary diagnostic tool for the evaluation of brain tumors preoperatively. NMR-based lipid estimation of post-surgical tumor tissue may also contribute to differentiating the tumor types.

An open controlled trial of 0.75 mg/Kg/day prednisolone was conducted at a stage when the patients had started falling several times in a day and stopped on their attaining a chair bound stage, thus minimising the total period of steroid therapy. Out of the 67 DMD patients enrolled in this study, 44 were put on prednisolone therapy and 23 served as controls. All patients were followed-up at two-monthly intervals for two years and thereafter they continued to take their respective medications till their chair-bound stage; then the drug was gradually withdrawn. In the treatment group 24 patients could not continue the trial because of adverse effects - 14 due to excessive obesity, 3 due to measles, 4 due to pulmonary tuberculosis, 2 due to recurrent throat and chest infection and 1 due to an unexplained high leukocyte count. Of the remaining 20 patients in the treatment group, steroid therapy was stopped in 5 patients as there was no improvement in power in six months. Fifteen patients in the treatment group and 19 patients in the control group could be followed regularly for 2 years and then up to chair-bound stage. Outcome parameters included fall frequency, peak expiratory flow rate, limb muscle power, ability to lift weights, time taken in getting up from squatting position, walking 9 metres and climbing 13 stairs. Maximum improvement was noted between 2 and 4 months while mild improvement in some parameters continued up to six months. All parameters remained stabilised for 1 year or so, after which there was slight deterioration. Deterioration at 2 years was, however, less than the natural course of events noted in control patients. Prednisolone treated patients and controls became chair bound at the mean age of 169 +/- 9 and 132 +/- 8 months respectively. Till the ideal stage of the disease and the type or dosage of starting steroid therapy is defined by specially designed studies, 0.75 mg/Kg/day prednisolone therapy may be started in DMD patients at the stage of frequent falls ( > 10 / day) on walking or increased get-up time ( > 10 s) as observed while testing Gowers' sign; this improves muscle power and timing of motor performance within 2-4 months of onset of therapy in about 75% of those who tolerate this therapy, with a possible gain of approximately 3 years in terms of independent walking.

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