Sandip Chatterjee

Exosome-mediated Delivery of the Intrinsic C-terminus Domain of PTEN Protects It From Proteasomal Degradation and Ablates Tumorigenesis

PTEN mutation is a frequent feature across a plethora of human cancers, the hot-spot being its C-terminus (PTEN-CT) regulatory domain resulting in a much diminished protein expression. In this study, the presence of C-terminus mutations was confirmed through sequencing of different human tumor samples. The kinase CKII-mediated phosphorylation of PTEN at these sites makes it a loopy structure competing with the E3 ligases for binding to its lipid anchoring C2 domain. Accordingly, it was found that PTEN-CT expressing stable cell lines could inhibit tumorigenesis in syngenic breast tumor models. Therefore, we designed a novel exosome-mediated delivery of the intrinsic PTEN domain, PTEN-CT into different cancer cells and observed reduced proliferation, migration, and colony forming ability. The delivery of exosome containing PTEN-CT to breast tumor mice model was found to result in significant regression in tumor size with the tumor sections showing increased apoptosis. Here, we also report for the first time an active PTEN when its C2 domain is bound by PTEN-CT, probably rendering its anti-tumorigenic activities through the protein phosphatase activity. Therefore, therapeutic interventions that focus on PTEN E3 ligase inhibition through exosome-mediated PTEN-CT delivery can be a probable route in treating cancers with low PTEN expression.

Epidermal growth factor receptor and proliferating cell nuclear antigen in astrocytomas

AIMS The involvement of various growth factors, growth factor receptors and proliferative markers in the molecular pathogenesis of astrocytic neoplasms are being studied extensively. Epidermal Growth Factor Receptor (EGFR) gene overexpression occurs in nearly 50% of cases of glioblastoma. Since EGFR and proliferating cell nuclear antigen (PCNA) are involved in mitogenic signal transduction and cellular proliferation pathway, we have studied the correlation between the expression of EGFR and PCNA labeling index in astrocytic tumors. MATERIALS AND METHODS We investigated the immunohistochemical expression of EGFR and PCNA using the appropriate monoclonal antibodies in 40 cases of astrocytic tumors of which 21 cases were glioblastoma, eight cases were Grade III or anaplastic astrocytomas and six cases were Grade II or diffuse astrocytomas and five cases were Grade I or pilocytic astrocytomas. RESULTS Both the EGFR expression and PCNA labeling index increase with increasing grades of astrocytomas with a significantly high percentage of cells showing positive staining for both EGFR and PCNA in GBM and Grade III astrocytomas compared to Grade II astrocytomas. The expression levels of both EGFR and PCNA were low in Grade I or pilocytic astrocytomas. CONCLUSIONS A significant correlation was found between EGFR overexpression and PCNA labeling index in Grade III and Grade II astrocytomas and glioblastoma. These suggest that the tumor proliferation, at least in higher grades of astrocytomas is dependent in some measure on EGF and EGFR-related signaling pathways.

Overview of post-infective hydrocephalus

IntroductionPost-infective hydrocephalus refers to accumulation of fluid within the cranial cavity (hydrocephalus) secondary to either pyogenic or tuberculous meningitis. Whereas in the former condition, fibrous adhesions develop in the ventricles and arachnoid villi, in the latter, the fibrosis is mainly basal.MethodsThis is a review of the authors personal series as well as published literature on post-infective hydrocephalus.ConclusionThe aim of treatment in hydrocephalus following pyogenic meningitis is to sterilize the cerebrospinal fluid (CSF) and then to drain the ventricles after conversion of a multiloculated cavity into a single cavity. In hydrocephalus associated with tuberculous meningitis, CSF diversion is not always necessary and should be reserved for cases where clinical deterioration occurs pari passu with increase in ventricular size and intraventricular pressure.

En plaque meningioma with angioinvasion

En plaque meningioma is a rare type of meningioma characterized by infiltrative nature, sheet-like growth and at times invading the bone. We report here a case of en plaque meningioma with typical grade I histomorphology along with unusual feature of angioinvasion. The patient was a 55-year-old man presenting with headache and painful proptosis of right eye. Imaging modalities revealed an en -plaque meningioma extending into the right sylvian fissure, with thickening of right temporal calvarium, greater wing of sphenoid and extension into the orbit. Magnetic resonance angiography showed medial displacement of right middle cerebral artery. The tumor was removed from the sylvian fissure and right temporal convexity. However, only subtotal removal of the intraorbital part was possible. Histology showed a meningothelial meningioma with low tumor cell proliferation, but infiltration into the bone, skeletal muscle and angioinvasion. Recognition of meningiomas en plaque is useful, as these tumors are difficult to resect completely, and are more prone to undergo recurrence or malignant change. In addition, angioinvasion seen in this tumor may have additional prognostic significance.

Intramedullary tumors in children

Intramedullary tumors of the spinal cord account for 35-40% of intraspinal tumors in children. The biological behavior of these tumors is of slow progression, and hence aggressive surgery has been advocated. Surgical adjuncts include use of intraoperative neurophysiological monitoring, preoperative ultrasound, microsurgical techniques and ultrasonic suction devices. Osteoplastic laminoplasty approaches avoid post-laminectomy deformities in younger children. Postoperative radiotherapy and more recently chemotherapy regimes have been proposed for incompletely resected tumors.

A study of histopathological spectrum and expression of Ki-67, TP53 in primary brain tumors of pediatric age group.

Objectives: The primary brain tumors are the second most common cause of death due to malignancies in children. This study was done to analyze the histological spectrum of primary brain tumors in children and also to find out the expression of p53 and Ki67 in some of the common pediatric brain tumors. Materials and Methods: This study was done over a period of 2.5 years. The patients were followed up until 6 months to determine the outcome. We examined H and E sections from 61 pediatric brain tumors and also performed immunohistochemical stains with p53 and Ki67 on 52 of these samples. Results: Of the 61 cases of pediatric brain tumors the commonest were pilocytic astrocytomas and medulloblastomas both constituting 22.9% of total cases, followed by high grade gliomas, that is, anaplastic astrocytoma and glioblastoma taken together (14.7%), diffuse astrocytomas (11.4%), ependymomas (8.1%), and oligodendrogliomas (4.9%). Other cases comprised craniopharyngiomas, astroblastomas, and gangliocytoma. The mean age of presentation was 9.3 years, male children being more commonly affected. Ki67 labeling index (LI) and p53 expression in pilocytic astrocytomas and diffuse astrocytomas were significantly lower than that of high-grade astrocytomas. However, there was no significant difference of expression of these two antigens in pilocytic astrocytomas and diffuse astrocytomas. It was found that Ki67 LI was a better marker for distinguishing between grades of astrocytoma than p53 (P=0.000 and P=0.002, respectively). The survival in cases of pilocytic astrocytomas was far better than high-grade gliomas. However, there was no significant difference in survival between pilocytic astrocytoma and diffuse infiltrating astrocytoma. There was significant positive correlation between expression of p53 and Ki67 LI in cases of medulloblastomas. Both p53 (P=0.002) and Ki67 LI (P=0.000) taken individually correlated well with survival in these cases. Also, Ki67 LI is better predictor of outcome than p53. Conclusion: From this study, it can be concluded that Ki67 and p53 score correlated well with the grade of astrocytoma; however, Ki67 is a better marker for differentiating between the grades of astrocytoma than p53. Also, Ki67 LI is a better prognostic factor than p53 in case of medulloblastomas.

Expression of phosphatase and tensin homolog, epidermal growth factor receptor, and Ki-67 in astrocytoma: A prospective study in a tertiary care hospital

Background: Though the tumor grade is a key factor influencing the choice of therapies, particularly determining the use of adjuvant radiation and specific chemotherapy protocols, role of abnormality in phosphatase and tensin homolog (PTEN) expression and variation in epidermal growth factor receptor (EGFR) labeling index (LI) and Ki-67 LI in survival and clinical outcome have been studied by many researchers in the recent past. Aims: The aim was to evaluate the expression of PTEN, EGFR and Ki-67 in different grades of astrocytic tumors by means of immunohistochemistry and to judge their role in overall survival (OS). Materials and Methods: This study was conducted on 57 cases of different grades of astrocytomas. Expression of PTEN, EGFR and Ki-67 was assessed by immunohistochemistry on formalin fixed and paraffin-embedded sections and the OS was evaluated by Kaplan–Meier survival curves and log-rank test for 2.5 years from the date of primary resection. Results: Most of the tumors (59.6%; 34 cases out of 57) displayed WHO Grade IV features. Distribution of age, EGFR LI and Ki-67 LI expressed strong positive (≥0.5) correlation with the grade of tumors. However, the PTEN positivity was inversely related with the grade of the tumors. Lower WHO grades, lower values of Ki-67 LI, EGFR LI and PTEN positivity were associated with better survival. Conclusion: Expression of PTEN, EGFR LI and Ki-67 LI should be combined with the basic histopathological features including WHO grade to predict the prognosis and therapeutic outcome.

Detection of progesterone receptor and the correlation with Ki-67 labeling index in meningiomas.

CONTEXT Although most of the meningiomas are benign, some of them are associated with a less favorable clinical outcome. The major prognostic question regarding meningiomas is the prediction of recurrence which is largely dependent on the histopathological type, grading, proliferation indices and progesterone receptor status. AIMS Our study was done to assess the expression of Ki-67 and progesterone receptor (PR) in different histological types, grades, recurrent and non-recurrent meningiomas. MATERIALS AND METHODS A total of 60 cases were collected over a period of 2.5 years. Hematoxylin and eosin staining was done for histological typing and grading of the tumors. Immunohistochemical staining was done for Ki-67 and PR using standard immunoperoxidase technique and Ki-67 Labeling Index (LI) and PR score was calculated. RESULTS Mean Ki-67 LI was significantly higher in males versus females, in Grade II versus Grade I, in recurrent versus non-recurrent and in PR-negative versus PR-positive meningiomas. Moreover, considering Grade I and Grade II-meningiomas separately, mean Ki-67 LI was significantly higher in recurrent cases. PR positivity was significantly higher in females versus males, in Grade I versus Grade II and in non-recurrent versus recurrent meningiomas. Correlation between Ki-67 LI and PR expression was also evaluated and a strong inverse correlation was found between Ki-67 LI and PR expression. A strong negative correlation was also established between the values of Ki-67 LI and recurrence-free survival. CONCLUSION Our results establish that the immunodetection of Ki-67 LI and PR expression in meningiomas provides a practical tool for assessing the biological behavior of meningiomas.

The spectrum of tuberculosis of the spine in pediatric age group: a review

IntroductionPediatric spinal tuberculosis is characterized by rapid bone destruction and carries the risk of rapid onset neurological deficits and severe deformity of the spine. Behavior of spinal deformity over time is affected by growth of spine. Owing to this dynamic behavior of pediatric spinal tuberculosis both in active phase and in healed phase, it presents with challenges which are quite different from adults with caries spine. A clinician must have high index of suspicion for accurate and early diagnosis of spinal tuberculosis in the pediatric population and should also have a thorough knowledge of differences in natural history between adult and pediatric spinal tuberculosis.DiscussionThis is based on the senior author’s experience of dealing with tuberculosis of the spine in children over the last two decades. Recent advances in field of rapid diagnosis of tuberculosis based on nuclear material-related diagnostic tests have further improved the management of tuberculosis. At the same time, the basic treatment principles remain the same. However, the threshold for surgical vs conservative treatment have subtle differences when compared to adult population. The importance of long-term follow-up after treatment must be appreciated.ConclusionTuberculosis in the spine in children needs early attention. Prompting to diagnostic and medical therapy measures can avoid neurological sequellae and delayed deformity.

Special Annual Issue on CNS Infections

Dear Editor: The brain and the spinal cord are truly well protected from infections by the skull and the bony spine and are surrounded by layers of meninges which form a strongmechanical barrier. This defense is reinforced by the chemical filtering capacity of the blood-brain barrier. In spite of this, infections do occur in the central nervous system (CNS). When they do occur, it can lead to poor outcomes and exorbitant healthcare costs. Yet infections of the CNS have been known from ancient times as the article by Kobets and Goodrich describes. Although the epidemiologic transition from infectious to degenerative disease has been completed in developed countries, the former remains an important source of morbidity and mortality worldwide, especially in less-developed countries and immunocompromised patients in the developed world. Recent resurgence of infections even in the developed world has been also attributed to immigration trends and improper use of antimicrobial drugs. Children form a more susceptible group as far as infections of the CNS are concerned, and these do not only cause temporary debility, but often leave behind a stigmata of permanent damage to the brain and spinal cord. This not only damages the individual child but also devastates the family and has serious implications in terms of the social cost of healthcare. It is with the aim of increasing awareness of this seldom discussed problem that this special annual issue is dedicated to the world’s children afflicted at some time with various infectious diseases. Infections of the skull and bony spine represent a dichotomy between the developed and developing world. In the former, postsurgical infections are common, and in the latter, scalp and paranasal sinus infections represent the common sources [1]. Cranial epidural abscesses are the third most common localized intracranial suppuration after brain abscesses and subdural empyema. Medical therapy together with surgical drainage is required in the majority of cases together with eradication of the source of infection [2]. Subdural empyemas, like epidural abscesses occur mainly in the pediatric population and often after bacterial meningitis. Surgical management is mandated in most cases as elaborated in the article by Muzumdar et al., the only controversy being in the use of corticosteroids [3, 4]. Brain abscesses, which are in fact intracerebral suppurative collections, represent the most dangerous infection of the CNS, as described in the article by WT Seow and colleagues. Whereas contiguous spread is common in developing countries, the heart and lung represent sources of hematogenous spread and are more common in the developed world. In about 25% cases, no source can be found. Aspiration versus excision remains the unanswered debate, with the treatment depending on the stage of the abscess formation [5]. Pyogenic ventriculitis is another life-threatening form of infection occurring mainly in children. Intravenous antibiotics have often got to be supplemented by intrathecal antibiotics and more recently with ventricular lavage [6, 7], a treatment not only directed at the infection, but also at the ensuing hydrocephalus. The article by UV Thomale’s group describes in details the procedure of ventricular lavage in this situation. It would appear that intraventricular administration of antibiotics would produce higher antibiotic concentrations in the fluid in the brain than intravenous administration alone and eliminate the bacteria more quickly. However, only one trial [8] exists, and this trial enrolling infants with gram-negative meningitis and ventriculitis, the use of intraventricular antibiotics in addition to intravenous antibiotics showed threefold increased risk for mortality compared to standard treatment with intravenous antibiotics alone. Based on this result, it would appear that intraventricular antibiotics should be * Chandrashekhar Deopujari d.chandrashekhar11@gmail.com