PDE4 inhibitor eliminates breast cancer stem cells via noncanonical activation of mTOR.

Ineffective cancer treatment is implicated in metastasis, recurrence, resistance to chemotherapy and radiotherapy, and evasion of immune surveillance. All these failures occur due to the persistence of cancer stem cells (CSCs) even after rigorous therapy, thereby rendering them as essential targets for cancer management. Contrary to the quiescent nature of CSCs, a gene profiler array disclosed that phosphatidylinositol-3-kinase (PI3K), which is known to be crucial for cell proliferation, differentiation, and survival, was significantly upregulated in CSCs. Since PI3K is modulated by cyclic adenosine 3',5' monophosphate (cAMP), analyses of cAMP regulation revealed that breast CSCs expressed increased levels of phosphodiesterase 4 (PDE4) in contrast to normal stem cells. In accordance, the effects of rolipram, a PDE4 inhibitor, were evaluated on PI3K regulators and signaling. The efficacy of rolipram was compared with paclitaxel, an anticancer drug that is ineffective in obliterating breast CSCs. Analyses of downstream signaling components revealed a switch between cell survival and death, in response to rolipram, specifically of the CSCs. Rolipram-mediated downregulation of PDE4A levels in breast CSCs led to an increase in cAMP levels and protein kinase A (PKA) expression. Subsequently, PKA-mediated upregulation of phosphatase and tensin homolog antagonized the PI3K/AKT/mTOR pathway and led to cell cycle arrest. Interestingly, direct yet noncanonical activation of mTOR by PKA, circumventing the influence of PI3K and AKT, temporally shifted the fate of CSCs toward apoptosis. Rolipram in combination with paclitaxel indicated synergistic consequences, which effectively obliterated CSCs within a tumor, thereby suggesting combinatorial therapy as a sustainable and effective strategy to abrogate breast CSCs for better patient prognosis.

Transforming growth factor beta orchestrates PD-L1 enrichment in tumor-derived exosomes and mediates CD8 T-cell dysfunction regulating early phosphorylation of TCR signalome in breast cancer.

Tumor cells promote immune evasion through upregulation of programmed death-ligand 1 (PD-L1) that binds with programmed cell death protein 1 (PD1) on cytotoxic T cells and promote dysfunction. Though therapeutic efficacy of anti-PD1 antibody has remarkable effects on different type of cancers it is less effective in breast cancer (BC). Hence, more details understanding of PD-L1-mediated immune evasion is necessary. Here, we report BC cells secrete extracellular vesicles in form of exosomes carry PD-L1 and are highly immunosuppressive. Transforming growth factor beta (TGF-ß) present in tumor microenvironment orchestrates BC cell secreted exosomal PD-L1 load. Circulating exosomal PD-L1 content is highly correlated with tumor TGF-ß level. The later also found to be significantly associated with CD8+CD39+, CD8+PD1+ T-cell phenotype. Recombinant TGF-ß1 dose dependently induces PD-L1 expression in Texos in vitro and blocking of TGF-ß dimmed exosomal PD-L1 level. PD-L1 knocked down exosomes failed to suppress effector activity of activated CD8 T cells like tumor exosomes. While understanding its effect on T-cell receptor signaling, we found siPD-L1 exosomes failed to block phosphorylation of src family proteins, linker for activation of T cells and phosphoinositide phospholipase Cγ of CD8 T cells more than PD-L1 exosomes. In vivo inhibition of exosome release and TGF-ß synergistically attenuates tumor burden by promoting Granzyme and interferon gamma release in tumor tissue depicting rejuvenation of exhausted T cells. Thus, we establish TGF-ß as a promoter of exosomal PD-L1 and unveil a mechanism that tumor cells follow to promote CD8 T-cell dysfunction.

MicroRNA-222 reprogrammed cancer-associated fibroblasts enhance growth and metastasis of breast cancer.

BACKGROUND: Cancer-associated fibroblasts (CAFs) are known to impact on tumour behaviour, but the mechanisms controlling this are poorly understood. METHODS: Breast normal fibroblasts (NFs) or CAFs were isolated from cancers by laser microdissection or were cultured. Fibroblasts were transfected to manipulate miR-222 or Lamin B receptor (LBR). The fibroblast-conditioned medium was collected and used to treat epithelial BC lines MDA-MB-231 and MDA-MB-157. Migration, invasion, proliferation or senescence was assessed using transwell, MTT or X-gal assays, respectively. RESULTS: MiR-222 was upregulated in CAFs as compared with NFs. Ectopic miR-222 expression in NFs induced CAF-like expression profiles, while miR-222 knockdown in CAFs inhibited CAF phenotypes. LBR was identified as a direct miR-222 target, and was functionally relevant since LBR knockdown phenocopied miR-222 overexpression and LBR overexpression phenocopied miR-222 knockdown. MiR-222 overexpression, or LBR knockdown, was sufficient to induce NFs to show the CAF characteristics of enhanced migration, invasion and senescence, and furthermore, the conditioned medium from these fibroblasts induced increased BC cell migration and invasion. The reverse manipulations in CAFs inhibited these behaviours in fibroblasts, and inhibited paracrine influences on BC cells. CONCLUSION: MiR-222/LBR have key roles in controlling pro-progression influences of CAFs in BC. This pathway may present therapeutic opportunities to inhibit CAF-induced cancer progression.

Cystic echinococcosis: A neglected disease at usual and unusual locations.

Echinococcus granulosus causes a zoonotic infection called cystic echinococcosis (CE) or more commonly known as hydatid disease. Although the two most common locations of hydatid cyst are liver and lung, it may also appear in other parts of the body. Clinical presentation of the hydatid disease depends on the site and size of the lesion. A retrospective study was done in Medical College and Hospital, Kolkata, from January 2012 to June 2014, to find the site of involvement, distribution, clinical features, history of contact, mode of presentation, laboratory diagnosis, and treatment modalities of the cases of hydatid cyst. The cases were identified by radiological and laboratory methods, the data were entered in Excel spreadsheet, and analysis was done. Among the 21 cases of hydatid cyst included in the study, solitary hepatic involvement was seen in 11 (52.38%), pulmonary involvement in 4 (19%), and 6 (28.71%) were in unusual locations such as liver cyst extending as retroperitoneal, omental cyst, choledochal cyst, splenic cyst, and in hepatorenal pouch. History of contact with dog was seen in 15 (71.43%). All the patients were treated with surgery and albendazole and were discharged in healthy condition. CE may be present in usual and unusual locations with a lot of variations in the clinical features. Hence, proper radiological and laboratory diagnosis is required for accurate diagnosis and appropriate management of these cases.

miR-216b suppresses breast cancer growth and metastasis by targeting SDCBP.

Breast cancer is the most deadly cancer among women and the second leading cause of cancer death worldwide. Treatment effectiveness is complicated with tumor invasiveness/drug resistance. To tailor treatments more effectively to individual patients, it is important to define tumor growth and metastasis at molecular levels. SDCBP is highly overexpressed and associated with a strikingly poor prognosis in breast cancer. However the post transcriptional regulation of SDCBP overexpression remains to be an unexplored area. Our study reveals that miR-216b directly regulates SDCBP expression by binding to its 3'UTR region. miR-216b is a tumor suppressive miRNA and it is underexpressed during metastatic breast cancer. Consequently, overexpression of miR-216b resulted in decreased proliferation, migration and invasion in BC cell lines by modulating the expression of SDCBP. Inhibition of miR-216b divergent the tumor suppressive role by inducing the growth proliferation, migration and invasion in vitro. There is therefore a negative correlation between the expression of miR-216b and its target gene SDCBP in the BC tissue samples as well as cell lines. Simultaneous expression of miR-216b and SDCBP rescued the growth, migration and invasion effect suggesting that tumor suppressive action of miR-216b may be directly mediated by SDCBP. In summary, the study identifies miR-216b as a regulator of SDCBP expression in breast cancer which can potentially be targeted for developing newer therapies for the effective treatment of this killer disease.

Unnecessary appendicectomy in suspected cases of acute appendicitis.

Acute appendicitis is a common emergency encountered by general surgeons and is managed effectively by timely appendicectomy. Open appendicectomy is usually the first abdominal operation which a surgical resident learns during his training. In this study, 912 appendicectomies were performed on clinical suspicion of acute appendicitis during the period of 6 years (2003-2008) at Medical College, Kolkata and all the appendix specimens were sent for histopathological confirmation. The negative appendicectomy rate in this study was 36.40% which was significantly higher (p < 0.01) than other contemporary studies. Similarly, females had a higher number of negative appendicectomy at 40.34% as against 26.80% for males ( p < 0.001). Of the 409 specimens (44.85%) thought of "normal" appendix intra-operatively, 77 came out to be having acute appendicitis in histopathology report (intra-operative assessment sensitivity of 86.72% and negative predictive value of 81.17%). So even though there is increased morbidity and mortality if acute appendicitis is not diagnosed early, there is always a tendency among surgeons for over diagnosis and adding to the cost of already burdened government healthcare centres in developing countries. A thorough work-up with pre-operative imaging and diagnostic laparoscopy where applicable is advised for appendicectomy before subjecting a patient presenting with right iliac fossa pain.

Clinicopathologic study of pelvic lesions managed by surgeons in a medical college in Kolkata in the last 2 years.

The pelvic cavity is a basin-like space in the lowermost part of the abdomen where various neoplastic and non neoplastic lesions can occur involving its contents. When the nature of lesions are not clearly gynecological, patients are managed by surgeons. Our study aims to asses the clinicopathologic analysis of neoplastic lesions of the pelvic cavity managed by surgeons particularly over a period of 2 years. Out of 162 total lesions, 102 cases were non neoplastic, such as appendicular lump, Tubo-ovarian (TO) mass, hematoma and 60 cases were neoplastic. Among the 60 cases of neoplastic lesions, 40 cases were benign comprised of twisted ovarian cyst, broad-ligament fibroid, and neurofibroma and 20 cases were malignant comprised of colorectal carcinoma, ovarian carcinoma, liposarcoma, Primitive nurectodermal tumor (PNET), seminoma, and lymphnode metastasis. The lesions in such closed, difficult to approach areas throws clinicians into a diagnostic dilemma during both the preoperative and intraoperative period. Even pathologists cannot ascertain some diagnosis without the help of immunohistochemistry. So, to adopt early and concise management protocol, there should be more such studies in different institutions that are currently lacking in world literature.

A retrospective study of lateralised transverse cosmetic incision appendicectomy.

In the present study 105 patients underwent appendicectomy by lateralised transverse cosmetic incision over a period from January, 2005 to September, 2007. Six patients developed complications like wound infection and fever. Wound infection was managed with antibiotics, postoperative pain with simple analgesics like tramadol hydrochloride and paracetamol. This cosmetic incision possesses maximum economic benefit. Even laparoscopic method takes more time, cost and skilled personnel.

Pancreaticogastrostomy in cases of chronic pancreatitis: a preliminary study.

Pancreaticogastrostomy is a less known operation for drainage. In this series pancreaticogastrostomy was done in 37 patients with dilated ducts during the period from 2002-2008. Anastomosis of the pancreas to the posterior wall of stomach was performed using pancreatic duct to gastric mucosa technique. The cases were followed up and it was seen that pancreaticogastrostomy is an effective operation for chronic pancreatitis. Most patients (89%) got relieved of pain for first several years. It is also a less time taking procedure to perform as no Roux-en-y construction is needed.