Understanding the mechanism of mTOR inhibition in human herpes virus-8 associated malignancies

In this dissertation, I have attempted to characterize the molecular features of Primary Effusion Lymphoma (PEL) and Kaposi's Sarcoma (KS) that render them addicted to the PI3K-mTOR pathway. PEL and KS constitute two signature diseases caused by Human Herpes Virus-8 (HHV8), or Kaposi's Sarcoma-associated Herpes Virus (KSHV), in immunocompromised individuals. KS is a cancer of endothelial cell origin and PEL a Diffuse-Large B-cell Lymphoma (DLBCL). We treated PEL cell lines in vitro and in vivo to show that sensitivity to Rapamycin, the major mTOR kinase inhibitor, is in part mediated by inhibition of interleukins: IL6 and IL10 (Sin, SH., Roy, D., et al.). We demonstrated that Phosphatase and Tensin homolog on chromosome-10 (PTEN), the major PI3K-mTOR negative regulator, is phosphorylated at Serine 380, in both PEL and KS. Reports in the literature have shown that phosphorylation at this residue results in a closed, inactive conformation of PTEN. This led us to speculate that unlike other cancers PTEN is inactivated not genetically, but via post-translational phosphorylation, in PEL and KS (Roy and Dittmer, in revision). Further, using the Affymetrix 6.0 SNP array we associated deletions in common fragile site tumor suppressor genes: FHIT and WWOX with PEL. We correlated EBV-negative PEL with increased genomic instability compared to EBV-positive (Roy et al., submitted). Using a newly developed L1T2 cell line we demonstrated efficacy of Rapamycin against KS-like tumors in mice. We showed that Rapamycin inhibited secretion of Vascular Endothelial Growth Factor (VEGF) in vitro, which translated into defective tumor vasculature and angiogenesis in vivo. Unlike treatment with chemotherapeutic Doxorubicin, Rapamycin did not increase tumor apoptosis. We noted that Rapamycin alone is more tumor inhibitory than in combination with Doxorubicin. This led us to speculate that tumorigenesis of KS is more dependent on optimal tumor microenvironment than tumor cell proliferation. Lastly, we conducted an AIDS Malignancy Consortium (AMC) study of Rapamycin in AIDS-associated KS. We noted partial response or stable disease in all the patients. Molecular analysis showed that we could target mTOR kinase activity in patients without adversely affecting their AIDS. These data collectively suggest that mTOR inhibition can be an effective therapeutic in transplant- and AIDS-associated HHV8 malignancies

Phosphatase and Tensin Homolog on Chromosome 10 Is Phosphorylated in Primary Effusion Lymphoma and Kaposi's Sarcoma

Primary effusion lymphoma (PEL) is a non-Hodgkin's B-cell lymphoma driven by Kaposi's sarcoma-associated herpesvirus. It is uniquely sensitive to mTOR, PI3K, and Akt inhibitors; however, the basis of this requirement for the mTOR pathway remains to be elucidated. The phosphatase and tensin homolog gene (PTEN) on chromosome 10 controls the first step in the phosphatidylinositol 3 kinase (PI3K)-Akt-mammalian target of rapamycin (mTOR) pathway and is genetically inactivated in many solid tumors. We find an absence of PTEN deletions, mutations, or protein mislocalization in PEL. However, we find consistent hyperphosphorylation at serine 380 of PTEN, which is an inactivating modification, in PEL cell lines and in tumor xenografts. We also evaluated a large tissue microarray of Kaposi's sarcoma biopsies and observed concordant high levels of phospho-PTEN, phospho-Akt, and phospho-S6 ribosomal protein. Reintroduction of PTEN into PEL inhibited colony formation in soft agar, verifying the functional dependence of PEL on PI3K signaling. This was also true for PEL cell lines that carried mutant p53 and for KS-like cell lines. Activating PTEN in these cancers may yield a new treatment strategy for PEL, KS, and similar PTEN wild-type lymphomas

Determinants of mTOR inhibitor therapy in AIDS-associated malignancies

Rapamycin/Sirolimus™ leads to the regression of transplant- associated Kaposi sarcoma (KS). It also leads to disease stabilization in HIV-associated KS. Case reports and a wealth of preclinical studies support rapamycin’s efficacy also in AIDS associated lymphoma, such as primary effusion lymphoma (PEL). Rapamycin inhibits the mammalian target of rapamycin (mTOR) and papamycin derivatives are approved for the treatment of mantle cell lymphoma and other cancers. It is not universally effective against all solid tumors. Even within this group of clinically responsive cancers, there are exceptions of cases or cell models in which this drug or its derivatives (rapalogs) fail

Design Of Dual Band Microstrip Antenna For Telephony System

Antennas are essential part of communication systems. Without antenna wireless connection become difficult. For effective communication, certain parameters need to be concerned. Depending upon the signal frequency the length of an antenna becomes very large. Microstrip antenna deals with this problem, where equivalent antenna can be designed in small size. This helps in integration of electronic and communication devices. This work presents broadband microstrip antennas for Telephony systems applications. Using co-linear patch design, microstrip antennas are made. These antennas are capable to work with GSM technology. This research also shows how an antenna can be designed within the same size, where antennas are operating in single band as well as multiban

A State-of-the-Art Review on Heat Extraction Methodologies of Photovoltaic/Thermal System

One of the critical emerging branches of solar technology is photovoltaic/thermal (PV/T) systems that amalgamate solar collectors and solar photovoltaic panels into a unit to produce heat and electricity from stochastic solar insolation. In sunny countries, the conversion efficiency ( η ) reduces due to the elevated temperature of solar cells because solar panels absorb a sizeable portion of solar insolation as heat. The critical function of PV/T is to minimize the temperature of photovoltaic modules and enhance their electricity production with yielded thermal energy used for other applications. Energy and exergy are two essential aspects of examining an energy system. The exergy analysis of such systems is of great concern because it works on the quality of energy. The energy and thermal and electrical efficiencies are enhanced by applying proper cooling media in the PV/T. This brief provides a comprehensive review of the air, fluids, and PCM-based cooling media of the PV/T systems. A thorough review of various recently published research in the heat extraction methodologies of PV/T systems has been incorporated into this study. Based on the rigorous review, future recommendations for the implementation of cooling medias are also included in this study. The vivid tabular analysis of heat extraction methodologies provides a proper guideline for the researchers. This review work will provide a deep insight into the investigated area for the industrialists and researchers working in the field of PV/T technology

Evaluation of Serum Vitamin B12 and Vitamin D Levels in Infertile Males with Suboptimal Semen Parameters- A Pilot Study from Eastern India

Introduction: According to World Health Organization (WHO), infertility is a disease defined by the inability to conceive a child after one year or more of unprotected and regular sexual intercourse. Not only female partner is responsible but male partner related factors play a crucial role in infertility. A key role of vitamin D in male reproductive organs has been suggested. Role of vitamin B12 in spermatogenesis has also been emphasised. Aim: To delineate if there is any significant association between serum vitamin B12 and vitamin D levels with semen parameters among infertile males belonging to the Eastern India. Materials and Methods: This cross-sectional study was conducted in Department of Biochemistry at Institute of Post Graduate Medical Education and Research and Seth Sukhlal Karnani Memorial Hospital, Kolkata, West Bengal, India, from May 2020 to July 2021. Fifty two infertile males of 25 to 40 years of age, with suboptimal semen parameters (semen volume, sperm count, sperm motility and sperm morphology were considered) were selected. Fasting (12 hours) blood samples were collected for estimation of serum vitamin B12 and vitamin D levels. Significance of association between each parameter with serum vitamin B12 and vitamin D levels was determined using Chi-square test and Fisher’s-exact test. Results were analysed using Statistical Package for Social Sciences (SPSS) version 25.0. A p-value less than 0.05 was considered as statistically significant. Results: Low serum vitamin D levels (<20 ng/mL) were detected in 10 (83.33% ) subjects with low semen volume and in 15 (65.21%) With low sperm count. No significant statistical association was found for vitamin D levels with semen volume and sperm count. Among subjects with abnormal sperm motility and morphology, low vitamin D levels were found in 37 (75.51%) and 16 (69.56%), respectively. A significant statistical association was found between vitamin D level and sperm motility (p-value=0.005) but not with sperm morphology. Amongst subjects with low semen volume and low sperm count, low vitamin B12 levels (<200 pg/ mL) were seen in 5 (41.6%) and 15 (65.21%), respectively. A significant statistical association was found between vitamin B12 level and sperm count (p-value=0.003). Among subjects with abnormal sperm motility and morphology, low vitamin B12 levels were present in 19 (38.77%) and 13 (56.52%) and there was a significant association between the variables p-value=0.037 and p-value=0.049, respectively. Conclusion: It can be concluded that vitamin B12 and vitamin D levels in infertile male subjects disturb normal physiological mechanisms required for being fertile. Hence, vitamin B12 and vitamin D supplementation may be suggested for improvement of semen quality

Nuclear factor kappa B pathway associated biomarkers in AIDS defining malignancies

The Nuclear Factor kappa B (NFkB) pathway is essential for many human cancers. Therapeutics such as bortezomib (Velcade™), which interfere with nuclear factor NF-kappa-B(NFkB)signaling are of great clinical interest. NFkB signaling, however, is multifaceted and variable among tissues, developmental, and disease entities. Hence, targeted biomarkers of NFkB pathways are of prime importance for clinical research. We developed a novel real-time qPCR-based NFkB array. Only mechanistically validated NFkB targets were included. We then used random-forest classification to define individual genes and gene combinations within the NFkB pathways that define viral lymphoma subclasses as well as Kaposi sarcoma (KS). Few NFkB targets emerged that were universally present in all tumor types tested, underscoring the need for additional tumor-type specific biomarker discovery. (i) We uncovered tissue of origin-specific tumor markers, specifically CD69, CSF-1, and complement factor B (C1QBP)for PEL; IL1-beta, cyclinD3 and CD48for KS. We found that IL12, jun-B, msx-1 and thrombospondin 2 were associated with EBV co-infection in PEL. (ii) We defined the NFkB signature of Epstein-Barr virus (EBV)positive AIDS-associated Burkitt lymphoma(BL). This signature identified CCR5 as the key marker. (iii) This signature differed from EBV negative BL consistent with the idea that EBV not only activates NFkB activity but that this virus also reprograms NFkB signaling towards different targets

Rapamycin With Antiretroviral Therapy in AIDS-Associated Kaposi Sarcoma: An AIDS Malignancy Consortium Study

The mammalian target of rapamycin (mTOR) is activated in Kaposi sarcoma (KS) and its inhibitor, rapamycin, has induced KS regression in transplant-associated KS. This study aimed to evaluate rapamycin's safety and toxicity in HIV-infected individuals with KS receiving antiretroviral therapy (ART), investigate rapamycin interactions with both protease inhibitor (PI)-containing and non-nucleoside reverse transcriptase inhibitor (NNRTI)-containing ART regimens, and assess clinical and biological endpoints including KS response and mTOR-dependent signaling

mTOR Inhibitors Block Kaposi Sarcoma Growth by Inhibiting Essential Autocrine Growth Factors and Tumor Angiogenesis

Kaposi’s Sarcoma (KS) originates from endothelial cells and it is one of the most overt angiogenic tumors. In Sub-Saharan Africa, where HIV and the Kaposi Sarcoma-associated Herpes Virus (KSHV) are endemic, KS is the most common cancer overall, but model systems for disease study are insufficient. Here we report the development of a novel mouse model of KS where KSHV is retained stably and tumors are elicited rapidly. Tumor growth was sensitive to specific allosteric inhibitors (rapamycin, CCI-779, RAD001) of the pivotal cell growth regulator mTOR. Inhibition of tumor growth was durable up to 130 days and reversible. mTOR blockade reduced VEGF secretion and formation of tumor vasculature. Together, the results demonstrated that mTOR inhibitors exert a direct anti-KS effect by inhibiting angiogenesis and paracrine effectors, suggesting their application as a new treatment modality for KS and other cancers of endothelial origin