Mutations in the acetylation hotspots of Rbl2 are associated with increased risk of breast cancer.

Retinoblastoma like protein-2 (Rbl2) is functionally regulated by phosphorylation and acetylation. Previously, we demonstrated that lysine K1083 (K1079 in human Rbl2) is a potential target for acetylation but its functional role remains elusive. We investigated alterations in human Rbl2 gene specifically targeting exons 19-22 harbouring acetylatable residues i.e. K1072, K1083 and K1115 through single stranded conformation polymorphism (SSCP) in breast cancer patients. The K1083 was found altered into arginine (R) in 51% of the cases but K1072 and K1115 remained conserved. The 'K1083R' mutation impairs the acetylation potential of this motif that may result in functional inactivation of Rbl2. These patients also showed poor survival outcome that highlights prognostic relevance of this residue. NIH3T3 cells expressing glutamine (K1083Q) mutated Rbl2 could not be arrested in G1 by serum starvation, whereas cells expressing Rbl2 with K1083R showed prolonged G1 arrest in fluorescence activated cell sorting (FACS) analysis. This suggests that K1083 acetylation is important for G1/S transition. Further, we performed molecular dynamic simulations (MDS) to analyse kinetics of residue K1083 with Cyc-D1/CDK4. Mutations at K1083 impaired this binding exposing neighbouring residues S1080, P1081, S1082 and R1084, hence enhancing the possibility of accelerated phosphorylation. S1080 has previously been reported as a promising candidate of cell cycle dependent phosphorylation in Rbl2. This highlights significance of mutations in the pocket domain of Rbl2 gene in breast cancer, and also strengthen the supposition that K1083 acetylation is pre-requisite for its phosphorylation.

Post-placental Intrauterine Device Insertion Versus Delayed Intrauterine Device Insertion: An Observational Study.

ABSTRACT: Immediate post-placental IUD insertion is defined as IUD insertion within 10 min of the expulsion of the placenta. Although the expulsion rate in post-placental insertion is higher than interval insertion, the benefits of highly effective contraception immediately after delivery may outweigh the risks of expulsion. AIMS: To compare post-placental IUD (PPIUD) insertion with interval IUD insertion (IIUD) in terms of safety, effect on menstrual cycle, efficacy and satisfaction. MATERIALS AND METHODS: After meeting all eligibility criteria, the patients were asked to choose between post-placental IUD insertion and interval/delayed IUD insertion. In PPIUD group, insertion was done within 10 min of expulsion of placenta by hand technique. Individuals in IIUD group were asked to return after 6 weeks for IUD insertion by withdrawal technique. Both the groups were followed at 6 weeks, 6 months, 12 months by history, physical examination, per speculum examination and ultrasonography. OBSERVATIONS: 238 patients were allocated to PPIUD group and 273 to IIUD group. In the PPIUD group, there was no bleeding/spotting demonstrable as it was masked by the lochia. Mild pain at insertion was seen in only 11 patients in the PPIUD group. Slight bleeding/spotting was seen in 7.8% patients in the IIUD group, while mild to moderate pain was seen in 39.9% patients. At 6 weeks, 6 months and 1 year follow up with regard to patients complaining of pelvic pain/dysmenorrhea, the difference between the two groups was not statistically significant. Our study found that irregular bleeding or spotting was more in interval insertion than in the post-placental group. The difference in the two groups was statistically significant at 6 weeks and 6 months, but was not significant at 1 year. There was no case of perforation in either group. Our study found a statistically significant difference in expulsion after post-placental compared to delayed insertion. The difference between the two groups was statistically significant (p = 0.006) for cumulative expulsion. However, for interval expulsion rate, the difference was not statistically significant (p = 0.6). In our study, continuation rates appear to be higher in the PPIUD group, but the difference is not statistically significant. CONCLUSION: PPIUD is a safe, easy and effective alternative to interval IUD insertion and qualifies to be popularized as a first-line contraceptive agent in eligible patients owing to its immediate and sustained contraceptive benefit, patient comfort, convenience and lower incidence of side effects.