MPhil Thesis

Expression and regulation of efflux transporters in chemoresistant breast, colon and ovarian cancer cells in Bangladeshi patients

Sun, 20 Apr 2025 00:00:00 GMT

Expression and regulation of efflux transporters in chemoresistant breast, colon and ovarian cancer cells in Bangladeshi patients Deb Nath, Sudipta Chemotherapy is a cornerstone in cancer treatment, but multidrug resistance (MDR) poses a substantial challenge. Hyperactivity of efflux pumps is one of the vital reasons to confer MDR. P-GP, MRP1 and ABCG2- these key ABC efflux pumps collectively transport a spectrum of chemotherapeutic drugs out of cells. HIF1A, a master regulator, is also associated with cancer biology, influencing cellular invasion, angiogenesis and metabolism. HuR regulates the expression of various carcinogenic molecules by mRNA trafficking, stabilization and enhancement of protein translation as well. Thereby this study addresses a crucial research gap in Bangladeshi population by inspecting the expression patterns of P-GP, MRP1 and ABCG2 in chemoresistant breast, colorectal and ovarian tissues. This study also aimed to delve into the mechanisms of drug resistance, focusing on HIF1A and HuR driven overexpression of ABC transporters, thus leading to chemoresistance. In this prospective study, 57 (chemoresistant) and 57 (paired control) tissue samples from Bangladeshi cancer patients were processed for immunofluorescence staining. The data showed the consistent co-expression of P-GP, MRP1 and ABCG2 across all cases, suggesting a potential synergistic function of transporter proteins in chemoresistance. The observations from this study also revealed that HIF1A and HuR overexpress in chemoresistant tissues, suggesting their pivotal role in chemoresistance mechanisms across malignancies and potential as therapeutic targets in Bangladeshi population. This study also suggests a direct regulation of P-GP, MRP1 and ABCG2 transcription by HIF1A that binds to the 'CGTG' sequence in the promoter regions. Besides, HuR might facilitate posttranscriptional mRNA stabilization by interacting with AU-rich elements (AREs) in the 3'UTR regions of the ABC transporters. Inhibition of these interactions of HIF1A and HuR appears as a promising approach to reverse chemoresistance. Thus, this study offers constructive insights for designing more efficient treatment strategies. This thesis is submitted for the degree of Master of Philosophy.

Detection of mutation and polymorphism in marker genes of cervical carcinoma in Bangladeshi patients

Sun, 13 Oct 2019 00:00:00 GMT

Detection of mutation and polymorphism in marker genes of cervical carcinoma in Bangladeshi patients Zohura, Fatima Tuj Cervical cancer is a gynaecologic cancer type that develops in the cervix. Annually 528,000 new cases of cervical cancer are reported with 266,000 deaths, which account for 8% mortality of all female cancer patients. Infection with specific human papillomavirus (HPV) types is considered the most severe risk factor for cervical cancer. In the context of our socioeconomic conditions, an increasing burden of this disease and high mortality rate prevail in Bangladesh. Although several researches related to the epidemiology, HPV vaccination, and treatment modalities have been carried out in our country, any research on mutation locations and frequencies in cervical cancer in Bangladesh is yet to be done. Among the high number of genes involved in different signal transduction and cell growth regulation pathways, five different genomic regions within the top three most frequently mutated genes in COSMIC database with a key role in the development of cervical cancers were selected to study mutation frequency in our patients. These genes are EGFR (Epidermal Growth Factor Receptor), KRAS (Kirsten rat sarcoma), and PIK3CA (phosphatidylinositol-4,5bisphosphate 3-kinase, catalytic subunit alpha). DNA from 46 cervical tissue samples were extracted and amplified by PCR, using 1 set of primers designed for EGFR and 2 sets of primers designed for two different regions of both PIK3CA and KRAS gene. PCR products were purified and sequenced through Sanger cycle sequencing strategy. In silico analysis was done in two steps: nucleotide sequence analysis and its corresponding amino acid analysis. The mutated protein structures were determined by homology modelling using SWISS-MODEL. In total, 39 mutations were found in 28 patient samples. Eleven different mutations (23.91%) were found in amplified EGFR gene fragments, among which 1 was common in seven patient samples. On the other hand, twenty four different mutations (52.17%) were found in PIK3CA gene fragment amplicons, among which 2 were found in more than 1 patient. Four mutations (8.7%) were found in KRAS gene fragment amplified products. Our study shows that except for KRAS, the frequency of observed mutations in our patients is higher than those reported earlier in other parts of the world. The study can be used as a basis to build a mutation database for cervical cancer in Bangladesh. With the possibility of targetable oncogenic mutations, further exploration can be oriented towards establishing future diagnostics, personalized medicine decisions, and other pharmaceutical applications for specific cancer subtypes. This thesis submitted for the degree of Master of Philosophy in The University of Dhaka.

Remedial Effects of Homeopathic Drugs against Chronic Suppuration of Ear Caused by Pathogenic Microorganisms

Mon, 07 Oct 2019 00:00:00 GMT

Remedial Effects of Homeopathic Drugs against Chronic Suppuration of Ear Caused by Pathogenic Microorganisms Hasan, Nazmul Chronic Suppurative Otitis Media (CSOM) is known as one of the most common infectious disease and is characterized by a persistent discharge from the middle ear through a perforated tympanic membrane. CSOM is considered as one of the most common cause of hearing impairment in the developing countries. Use and misuse of antibiotics for treating CSOM promotes antibiotic resistance leading to accelerated public health risks. Homeopathic medicines are mostly free from side effects, and therefore, this study was performed to evaluate the effects of homeopathic medicines for remedies of CSOM symptoms. A total of 70 subjects were included in this study; among them, 40 were suffering from CSOM and 30 were healthy control. The CSOM patients were randomly assigned for daily administration of homeopathic medicines such as tellurium metallicum in 6C potency (n=17), mercurius solubilis in 200C potency (n=13 ) and calcarea sulphurica in 30C potency (n=10 )for 8 weeks. Aural swab of the patients were examined to assess microbiological infection. Identification of the isolated microorganisms such as Staphylococcus sp., E coli, klebsiella sp. was confirmed with Analytical Profile Index (API ). The homeopathic medicines did not show significant antibacterial activity when assessed by agar disc diffusion; however, they reduced average microbial load significantly. Ear suppuration was prevented in all of the patients treated with the medicines. The patients were also examined with otoscope to observe the level of their tympanic membrane perforation and the healing of the perforated membrane after treatment. Among the seventeen (17) patients suffering from CSOM associated with membrane perforation, 9 patients’ (52.9% ) membranes were healed when treated with tellurium metallicum. Calcarea sulphurica also healed perforated tympanic membranes of 50% patients, however, mercuris solibulis failed to trigger membrane healing in treated patients. It was next examined whether the patients also had hearing impairment compared to healthy control subjects. The average hearing thresholds of the control subjects (n=30) at 1, 4, 8 and 12 kHz frequencies were 13.55 ± 1.57, 15.58 ± 1.12, 27.58 ± 2.00 and 32.57 ± 2.45 dB SPL, respectively. When the average hearing thresholds of the CSOM patients (n=40) were measured at all of the above frequencies, the values became 30.25 ± 1.75, 36.80 ± 3.25, 50.75 ± 2.35, and 59.50 ± 2.96 dB SPL, respectively. This result indicated that the CSOM patients were suffering from hearing loss as the average hearing thresholds of the CSOM patients at all the frequencies tested were significantly higher (p<0.05)than that of the control subjects. To our surprise, treatment for 8 weeks with all three homeopathic medicines significantly reduced (p<0.05) hearing thresholds of the patients at all the frequencies. This result clearly indicated that the patients experienced dramatic improvement in hearing by the homeopathic medicines. This study, therefore, provides conclusive evidence that homeopathic medicines prevent ear suppuration in CSOM patients as well as reduce microbial load, heal perforated membrane and improve hearing. This thesis submitted for the degree of Master of Philosophy in The University of Dhaka.