علا عماد عكوبي ال-زبيبة

The development of chemoresistance is a major obstacle facing the successful translation of therapies from bench to bedside. For instance, resistance to Ibrutinib, the first line treatment for mantle cell lymphoma and other B cell malignancies, have been reported in different studies. Objective: In this study, we report that a novel combination therapy of different statins with Ibrutinib can overcome such resistance. Methods: For this, we generated a cell line model, exhibiting resistance to Ibrutinib, by repeated exposure of mantle cell lymphoma cell line to Ibrutinib. Apoptosis was assessed by the extent of phosphatidylserine externalisation. Results: Our results indicated that resistance to Ibrutinib could be overcome by targeting a key enzyme, 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase in the cholesterogenesis pathway. Conclusion: Reusing different statins in combination with Ibrutinib could improve therapy and enhance sensitivity to Ibrutinib mediated apoptosis.

Abstract BH3 mimetics are novel targeted drugs with remarkable specificity, potency and enormous potential to improve cancer therapy. However, acquired resistance is an emerging problem. We report the rapid development of resistance in chronic lymphocytic leukemia cells isolated from patients exposed to increasing doses of navitoclax (ABT-263), a BH3 mimetic. To mimic such rapid development of chemoresistance, we developed simple resistance models to three different BH3 mimetics, targeting BCL-2 (ABT-199), BCL-XL (A-1331852) or MCL-1 (A-1210477), in relevant hematologic cancer cell lines. In these models, resistance could not be attributed to either consistent changes in expression levels of the anti-apoptotic proteins or interactions among different pro- and anti-apoptotic BCL-2 family members. Using genetic silencing, pharmacological inhibition and metabolic supplementation, we found that targeting glutamine uptake and its downstream signaling pathways, namely glutaminolysis, reductive carboxylation, lipogenesis, cholesterogenesis and mammalian target of rapamycin signaling resulted in marked sensitization of the chemoresistant cells to BH3 mimetic-mediated apoptosis. Furthermore, our findings highlight the possibility of repurposing widely used drugs, such as statins, to target intermediary metabolism and improve the efficacy of BH3 mimetic therapy.

Squamous cell carcinoma of the head and neck (SCCHN) is the sixth most common cancer worldwide, with overall survival of less than 50%. Current therapeutic strategies involving a combination of surgery, radiation, and/or chemotherapy are associated with debilitating side effects, highlighting the need for more specific and efficacious therapies. Inhibitors of BCL- 2 family proteins (BH3 mimetics) are under investigation or in clinical practice for several hematological malignancies and show promise in solid tumors. In order to explore the therapeutic potential of BH3 mimetics in the treatment of SCCHN, we assessed the expression levels of BCL-2, BCL-XL, and MCL-1 via Western blots and immunohistochemistry, in cell lines, primary cells derived from SCCHN patients and in tissue microarrays containing tumor tissue from a cohort of 191 SCCHN patients. All preclinical models exhibited moderate to high levels of BCL-XL and MCL-1, with little or no BCL-2. Although expression levels of BCL-XL and MCL-1 did not correlate with patient outcome, a combination of BH3 mimetics to target these proteins resulted in decreased clonogenic potential and enhanced apoptosis in all preclinical models, including tumor tissue resected from patients, as well as a reduction of tumor volume in a zebrafish xenograft model of SCCHN. Our results show that SCCHN is dependent on both BCL-XL and MCL-1 for apoptosis evasion and combination therapy targeting both proteins may offer significant therapeutic benefits in this disease.

Abstract Maintenance of mitochondrial integrity is critical for normal cellular homoeostasis. Most cells respond to stress stimuli and undergo apoptosis by perturbing mitochondrial structure and function to release proteins, such as cytochrome c, which are essential for the execution of the intrinsic apoptotic cascade. Cancer cells evade these events by overexpressing the anti-apoptotic BCL-2 family of proteins on mitochondrial membranes. Inhibitors of the anti-apoptotic BCL-2 family proteins, also known as BH3 mimetics, antagonise the pro-survival functions of these proteins and result in rapid apoptosis. Although the precise mechanism by which BH3 mimetics induce apoptosis has been well characterised, not much is known in terms of the structural changes that occur in mitochondria during apoptosis. Using a panel of highly selective BH3 mimetics and a wide range of cell lines, we demonstrate that BH3 mimetics induce extensive mitochondrial fission, accompanied by swelling of the mitochondrial matrix and rupture of the outer mitochondrial membrane. These changes occur in a BAX/ BAK-dependent manner. Although a major mitochondrial fission GTPase, DRP-1, has been implicated in mitochondrial apoptosis, our data demonstrate that DRP-1 might function independently/downstream of BH3 mimetic-mediated mitochondrial fission to facilitate the release of cytochrome c and apoptosis. Moreover, downregulation of DRP-1 prevented cytochrome c release and apoptosis even when OPA1, a protein mediating mitochondrial fusion, was silenced. Although BH3 mimetic-mediated displacement of BAK and other BH3-only proteins from BCL-XL and MCL-1 was unaffected by DRP-1 downregulation, it prevented BAK activation significantly, thus placing DRP-1 as one of the most critical players, along with BAX and BAK, that governs BH3 mimetic-mediated cytochrome c release and apoptosis.

Abstract Induction of apoptosis by selective BH3-mimetics is currently investigated as a novel strategy for cancer treatment. Here, we report that selective BH3-mimetics induce apoptosis in a variety of hematological malignancies. Apoptosis is accompanied by severe mitochondrial toxicities upstream of caspase activation. Specifically, the selective BH3-mimetics ABT-199, A-1331852 and S63845, which target BCL-2, BCL-XL and MCL-1, respectively, induce comparable ultrastructural changes including mitochondrial swelling, a decrease of mitochondrial matrix density and severe loss of cristae structure. These shared effects on mitochondrial morphology indicate a similar function of these anti-apoptotic BCL-2 proteins in maintaining mitochondrial integrity and function.

Our study was aimed to investigate the effect of arsenic chloride (AsCl3) on the production of the tumor suppressor protein (P53) in the rat and study the ameliorate effect of Myrtus communis leaves on decreasing the toxicity of AsCl3. Here, 12 Wistar rats were used and randomly divided into 4 groups (3 rats/group). The 1st-group, T1, rats were administrated 10mg/kg BW of AsCl3 only. The 2nd-group, T2, rats were given 10mg/kg BW of AsCl3 and 3mg/ml of myrtle extract. The 3rd-group, T3, rats were supplied with 3mg/ml of myrtle extract only. The 4th-group rats were provided with 0.2ml of distilled water as a control group, C. A P53-based gene expression (PGE) analysis was introduced using a real time PCR (RT-PCR) technique. The results recorded higher levels of the PGE in the T3 group and followed by lower values in the T1 group when both compared with other groups. This study shows that AsCl3 induces negative effects on the PGE levels and probably the protein activity of P53 gene resulting in low gene expression; however, Myrtus communis improves the status by increasing the levels of PGE if used alone or mixed with AsCl3.

haematological comparative study was the main objectives of this project between the influence of ethanolic extract of Vinca rosea and Vinblastine (vinca alkaloid) as chemotherapy. Fourty female adult Swiss albino balb/C mice of approximately body weight (20-26g) and age (8-10) weeks were used

Pathological, cytogenetical comparative study was the main objectives of this project between the influence of ethanolic extract of Vinca rosea and Vinblastine (vinca alkaloid) as chemotherapy. Fourty female adult Swiss albino balb/C mice of approximately body weight (20-26g) and age (8-10) weeks were used in whole experiments. In cytogenetic study two parameters mitotic index (MI) and blast index (BI) were used. The results showed significant increase (p‹0.05) in mitotic index (MI) and blast index (BI) values in groups treated with ethanolic extract of Vinca rosea. Also the results showed significant decrease in these values in groups treated with Vinblastine. Histopathological sections in control group showed the presence of tumor growth characterized by formation of acinar like structures, with pleomorphic tumor cells and hyperchromatic nuclei with a tendency to form giant cells and high numbers of mitotic figures with extensive areas of necrosis. The tumor showed metastasis in liver and Lung, with aggregation of tumor associated macrophages in liver. Histopathological sections in groups of tumor-bearing female mice, treated with ethanolic extract, were showed large areas of necrosis, mononuclear cell infiltration and encapsulate with fibrous connective tissue capsule with mononuclear cell infiltrations in lung and formation of early granuloma in liver. In chemotherapy, tissue sections showed vacuolation and necrosis of tumor cells which encapsulated with fibrous connective tissue. The pathological changes characterized by alopecia, and large pneumonic areas with extensive coagulative necrosis and apoptosis in liver with hyperplastic nodules formation. Bone section showed marked depletion of hemopoietic tissue of bone marrow and increased in the number of megakaryocytes, with signs of osteoporosis. We concluded that both ethanolic extract of Vinca rosea and Vinblastine have cytotoxic effect on transplanted mammary tumor cells in mice, with no side effect in case of Vinca rosea in comparison with vinblastine which cause severe pathological changes in internal target organs with signs of osteoporosis and precancerous lesions, with significant changes in the blood picture and in cytogenetic parameters.

Marek’s disease (MD) is a highly infectious poultry illness with a tendency to form tumours in peripheral nerves and internalorgans of afected birds. Tumours accompany MD, mostly caused by oncogenic Gallid alpha herpesvirus 2 (MD Herpes virusserotype I). Studies on avian tumours associated with MD infection are limited in Iraq. In the presented study, the positive samplesof ocular tumour were 168 out of 282 MD positive samples, which accomplished in farm sufered from an unexpectedly highmortality rate. We investigated a rapidly developed tumour mass that was observed in an MD-vaccinated layer fock that showedobvious clinical signs of MD, accompanied by forming a small lump in one eye at age 21 weeks, which developed to a big lump atweek 28 of age, leading to death. Te diagnosis MD infection was confrmed by a Polymerase Chain Reaction (PCR) amplifcationof a specifc region of the target gene meq of the causative agent, followed by Sanger sequencing and BLASTn search of thesequence against the NCBI nucleic acid database, resulted in Gallid alpha herpes virus 2 strain, and according to the phylogeneticanalysis, the sequence from this study was uniquely clustered in its own branch in the tree. Histopathological examination of theocular tumour core revealed aggregation of neoplastic cells and haemorrhage that replaced the normal eye tissue, as well as earlytumour formation in internal organs such as the lung and liver. In addition, abnormal lesions are susceptible to tumours in thegizzard and spleen. To our knowledge, this is the frst record of an aggressive MD virus infection-mediated ocular tumour ina layer fock in Al-Najaf province, Iraq