Sk Singh

Gemcitabine and mitomycin induced autophagy regulates cancer stem cell pool in urothelial carcinoma cells

Urothelial carcinoma (UC) is characterized by therapeutic resistance and frequent tumor relapse. It has been suggested that UC are driven by a rare subset of cancer stem cells (CSCs). In order to understand UC recurrence post therapy, we investigated the behavior of urothelial CSCs after exposure to commonly used chemotherapeutic agents, gemcitabine (GC) and mitomycin (MM). Although, the role of autophagy in CSC maintenance is well documented, the relationship of autophagy and CSCs with respect to drug resistance remains elusive. In the present study, we found that both GC and MM increased the percentage of CSCs in primary cultured urothelial carcinoma cells (UCC). These CSCs exhibited higher autophagy flux and higher expression of glycolytic genes. Inhibition of autophagy led to decrease in the expression of glycolysis genes. Inhibition of autophagy and glycolysis caused decrease in expression of stemness genes (Oct-4, Nanog), drug resistance genes (ABCG2, MDR1) and sensitized CSCs to GC and MM induced apoptosis. This finding suggests that autophagy and glycolysis may play a central role in drug resistance. Altogether, we conclude that autophagy may support cell survival by buffering bioenergetic demands for maintenance of high glycolytic flux in CSCs. Therefore, autophagy-based, customized combinatorial approaches may provide a new method to counter CSC-driven resistance and may prevent relapse in UC. The synergistic cytotoxic effect of GC/ MM with autophagy inhibitor (chloroquine) or with glycolytic inhibitor (2-deoxyglucose) may be of help in improving the outcome in patients with urothelial carcinoma of urinary bladder.

JAK-mediated autophagy regulates stemness and cell survival in cisplatin resistant bladder cancer cells.

BACKGROUNDnAutophagy is a critical process in acquiring drug resistance in solid tumors. However, the mechanisms by which autophagy modulate resistance to chemotherapy in bladder cancer remains poorly understood.nnnMATERIAL AND METHODSnWe have established cisplatin resistant patient derived primary cultured cells as well as T24 bladder cancer cells. The autophagy flux as well as the effect of chemotherapeutic agents, gemcitabine (GC) and mitomycin (MM) were evaluated in these cells. Side population analysis, tumorisphere assay and expression of stemness genes were also studied to evaluate the role of autophagy during chemoresistance. The role of cytokines in autophagy induced chemoresistance was demonstrated.nnnRESULTSnOur results show that resistant cells have higher basal autophagic flux. GC and MM led to increase in autophagy and combination of autophagy inhibitors synergistically inhibited bladder cancer cell growth. When autophagy was inhibited, only IFN-γ level was decreased in cytokine array. Blocking IFN-γ decreased JAK2 expression and reduced the autophagy. Inhibition of JAK2 decreased the proportion of cancer stem cell enriched side population, tumor sphere forming ability and led to decrease in expression of stemness genes. Combined treatment with inhibitors of JAK2 and autophagy led to inhibition in cell growth, reduced the levels of inflammatory cytokines and decreased the resistance gene expression.nnnCONCLUSIONnGC and MM treatment increased autophagy process via IFN-γ mediated JAK2 and STAT3 pathway.nnnGENERAL SIGNIFICANCEnThese findings support a key role of the autophagy in drug resistance. Thus, autophagy-based, customized combinatorial approaches may effectively manage resistance and relapse in bladder cancer.

Scratch to state-of-the-art: setting up a new robotic facility in a developing country

The potential challenges encountered for setting up a robotic assisted surgical facility in developing country like India are many. We describe the initial hurdles and troubleshooting in establishing a facility of such kind. This experience might help to decrease initial hiccups in setting up such an innovative technology at other institutes.

Bladder paraganglioma: safe and feasible management with robot assisted surgery

Pheochromocytomas of extra-adrenal origin are known as paragangliomas. Urinary bladder is the most common site of genitourinary paragangliomas. The variable functional status of these tumors presents a surgical challenge in their management by minimally invasive surgery. Robot-assisted partial cystectomy offers the advantage of minimal handling of tumor, early ligation of feeding vessels and easy suturing. We hereby report the feasibility and safety of robot-assisted surgery in the management of one such case.

Dosimetric comparison of standard three-dimensional conformal radiotherapy followed by intensity-modulated radiotherapy boost schedule (sequential IMRT plan) with simultaneous integrated boost-IMRT (SIB IMRT) treatment plan in patients with localized carcinoma prostate

Aims: Dosimeteric and radiobiological comparison of two radiation schedules in localized carcinoma prostate: Standard Three-Dimensional Conformal Radiotherapy (3DCRT) followed by Intensity Modulated Radiotherapy (IMRT) boost (sequential-IMRT) with Simultaneous Integrated Boost IMRT (SIB-IMRT). Material and Methods: Thirty patients were enrolled. In all, the target consisted of PTV P + SV (Prostate and seminal vesicles) and PTV LN (lymph nodes) where PTV refers to planning target volume and the critical structures included: bladder, rectum and small bowel. All patients were treated with sequential-IMRT plan, but for dosimetric comparison, SIB-IMRT plan was also created. The prescription dose to PTV P + SV was 74 Gy in both strategies but with different dose per fraction, however, the dose to PTV LN was 50 Gy delivered in 25 fractions over 5 weeks for sequential-IMRT and 54 Gy delivered in 27 fractions over 5.5 weeks for SIB-IMRT. The treatment plans were compared in terms of dose–volume histograms. Also, Tumor Control Probability (TCP) and Normal Tissue Complication Probability (NTCP) obtained with the two plans were compared. Results: The volume of rectum receiving 70 Gy or more (V > 70 Gy) was reduced to 18.23% with SIB-IMRT from 22.81% with sequential-IMRT. SIB-IMRT reduced the mean doses to both bladder and rectum by 13% and 17%, respectively, as compared to sequential-IMRT. NTCP of 0.86 ± 0.75% and 0.01 ± 0.02% for the bladder, 5.87 ± 2.58% and 4.31 ± 2.61% for the rectum and 8.83 ± 7.08% and 8.25 ± 7.98% for the bowel was seen with sequential-IMRT and SIB-IMRT plans respectively. Conclusions: For equal PTV coverage, SIB-IMRT markedly reduced doses to critical structures, therefore should be considered as the strategy for dose escalation. SIB-IMRT achieves lesser NTCP than sequential-IMRT.