Intestinal Lymphatic Biology, Drug Delivery and Therapeutics: Current status and Future directions.

Historically, the intestinal lymphatics were considered passive conduits for fluids, immune cells, dietary lipids, lipid soluble vitamins and lipophilic drugs. Studies of intestinal lymphatic drug delivery in the late 20th century focussed primarily on the drug physicochemical properties, especially high lipophilicity, that resulted in intestinal lymphatic transport. More recent discoveries have changed our traditional view by demonstrating that the lymphatics are active, plastic and tissue-specific players in a range of biological and pathological processes, including within the intestine. These findings have, in turn, inspired exploration of lymph-specific therapies for a range of diseases, as well as the development of more sophisticated strategies to actively deliver drugs or vaccines to the intestinal lymph, including a range of nanotechnologies, lipid prodrugs and lipid-conjugated materials that 'hitchhike' on lymphatic transport pathways. With the increasing development of novel biological therapeutics there has been interest in whether these novel therapeutics are absorbed and transported through intestinal lymph after oral administration. Here we review the current state of understanding of the anatomy and physiology of the gastrointestinal lymphatic system in health and disease, with a focus on aspects relevant to drug delivery. We summarise the current state-of-the-art approaches to deliver drugs and quantify their uptake into the intestinal lymphatic system. Finally, and excitingly, we discuss recent examples of significant pharmacokinetic and therapeutic benefits achieved via intestinal lymphatic drug delivery. We also propose approaches to advance the development and clinical application of intestinal lymphatic delivery strategies into the future. Significance Statement This comprehensive review details understanding of the anatomy and physiology of the intestinal lymphatic system in health and disease, with a focus on aspects relevant to drug delivery. It highlights current state-of-the-art approaches to deliver drugs to the intestinal lymphatics and the shift toward the use of these strategies to achieve pharmacokinetic and therapeutic benefits for patients.

Intra-articular Injection of a B Cell Depletion Antibody Enhances Local Exposure to the Joint-Draining Lymph Node in Mice with Collagen-Induced Arthritis.

Changes to the number, type, and function of immune cells within the joint-draining lymphatics is a major contributor to the progression of inflammatory arthritis. In particular, there is a significant expansion in pathogenic B cells in the joint-draining lymph node (jdLN). These B cells appear to clog the lymphatic sinuses in the lymph node, inhibit lymph flow, and therefore, reduce the clearance of inflammatory fluid and cells from the joint. Taken together, there is potential to treat inflammatory arthritis more effectively, as well as reduce off-target side effects, with localized delivery of B-cell depleting therapies to the jdLNs. We recently reported that joint-draining lymphatic exposure of biologic disease-modifying anti-rheumatic drugs (DMARDs), including the B cell depletion antibody rituximab, is increased in healthy rats following intra-articular (IA) compared to subcutaneous (SC) or intravenous (IV) administration. This suggests that IA administration of B cell depleting antibodies may increase delivery to target cells in the jdLN and increase the effectiveness of B cell depletion compared to standard SC or IV administration. However, whether enhanced local delivery of DMARDs to the jdLN is also achieved after IA injection in the setting of inflammatory arthritis, where there is inflammation in the joint and jdLN B cell expansion is unknown. We, therefore, assessed the lymph node distribution, absorption and plasma pharmacokinetics, and B cell depletion at different sites after IA, SC, or IV administration of a fluorescently labeled mouse anti-CD20 B cell depleting antibody (Cy5-αCD20) in healthy mice compared to mice with collagen-induced arthritis (CIA). The absorption and plasma pharmacokinetics of Cy5-αCD20 appeared unaltered in mice with CIA whereas distribution of Cy5-αCD20 to the jdLNs was generally increased in mice with CIA, regardless of the route of administration. However, IA administration led to greater and more specific exposure to the jdLNs. Consistent with increased Cy5-αCD20 in the jdLNs of CIA compared to healthy mice, there was a greater reduction in jdLN weight and a trend toward greater jdLN B cell depletion at 24 h compared to 4 h after IA compared to SC and IV administration. Taken together, this data supports the potential to improve local efficacy of B cell depletion therapies through a jdLN-directed approach which will enable a reduction in dose and systemic toxicities.

Validation of the Amharic Version of the Brief Pain Inventory for Utility in Ethiopian Cancer Patients.

BACKGROUND: Pain is a highly prevalent and distressing symptom in patients with cancer but at the same time inadequately treated in many of these patients. The major reason for such imbalance is inappropriate pain assessment. To overcome such a barrier, the use of a valid and reliable pain assessment tool in the language the patient understands is invaluable. Unfortunately, until now, no such standardized tool has been utilized in Ethiopian patients with cancer for both clinical and research purposes. OBJECTIVES: This study tried to validate the Amharic language version of the Brief Pain Inventory (BPI-Am) and evaluate the adequacy of cancer pain management using the Pain Management Index (PMI). METHODS: A standard forward/backward translation technique was used for translating the BPI from its original English version into Amharic (BPI-Am). The BPI-Am was administered to 291 Ethiopian patients with cancer who fulfilled the inclusion criteria. Factor analysis was used to identify the underlying constructs of the tool. Mean comparison was used to confirm the sensitivity of the BPI-Am to known patient groups that differed based on their performance status. Cronbach's α and intraclass correlation coefficients, respectively, were used to assure internal consistency and test-retest reliability of the BPI-Am. The PMI was calculated to identify the level of inadequate pain management in the current sample. Stepwise logistic regression was used to identify potential predictors of inadequate pain management. RESULTS: Factor analysis yielded 3 factors-pain severity, physical activity interference, and psychosocial interference-with Cronbach's α coefficients of 0.85, 0.87, and 0.77, respectively. The BPI-Am showed the capacity to detect higher mean pain severity and mean pain interference scores in patients with poor performance status as compared with those having a good performance status (P < 0.001). Intraclass correlation coefficients for test-retest reliability were 0.75 and 0.78 for the pain severity and pain interference composite scores, respectively. Sixty-seven percent of patients in the current sample were inadequately treated for their pain according to the PMI. Good performance status (odds ratio [OR] = 2.9, P < 0.01), absence of cancer-related complications (OR = 2.1, P < 0.05), and being unemployed (OR = 2.6, P < 0.01) were identified as predictors of inadequate pain management. CONCLUSION: The BPI-Am is a valid and reliable tool for use in Ethiopian patients with cancer. The inadequacy of cancer pain management in these groups of patients is high, which calls for needed attention.

An Orally Bioavailable and Highly Efficacious Inhibitor of CDK9/FLT3 for the Treatment of Acute Myeloid Leukemia.

Mutations in FMS-like tyrosine kinase 3 (FLT3) occur in approximately one-third of AML patients and are associated with a particularly poor prognosis. The most common mutation, FLT3-ITD, is a self-activating internal tandem duplication (ITD) in the FLT3 juxtamembrane domain. Many FLT3 inhibitors have shown encouraging results in clinical trials, but the rapid emergence of resistance has severely limited sustainable efficacy. Co-targeting of CDK9 and FLT3 is a promising two-pronged strategy to overcome resistance as the former plays a role in the transcription of cancer cell-survival genes. Most prominently, MCL-1 is known to be associated with AML tumorigenesis and drug resistance and can be down-regulated by CDK9 inhibition. We have developed CDDD11-8 as a potent CDK9 inhibitor co-targeting FLT3-ITD with Ki values of 8 and 13 nM, respectively. The kinome selectivity has been confirmed when the compound was tested in a panel of 369 human kinases. CDDD11-8 displayed antiproliferative activity against leukemia cell lines, and particularly potent effects were observed against MV4-11 and MOLM-13 cells, which are known to harbor the FLT3-ITD mutation and mixed lineage leukemia (MLL) fusion proteins. The mode of action was consistent with inhibition of CDK9 and FLT3-ITD. Most importantly, CDDD11-8 caused a robust tumor growth inhibition by oral administration in animal xenografts. At 125 mg/kg, CDDD11-8 induced tumor regression, and this was translated to an improved survival of animals. The study demonstrates the potential of CDDD11-8 towards the future development of a novel AML treatment.

CDK9: A Comprehensive Review of Its Biology, and Its Role as a Potential Target for Anti-Cancer Agents.

Cyclin-dependent kinases (CDKs) are proteins pivotal to a wide range of cellular functions, most importantly cell division and transcription, and their dysregulations have been implicated as prominent drivers of tumorigenesis. Besides the well-established role of cell cycle CDKs in cancer, the involvement of transcriptional CDKs has been confirmed more recently. Most cancers overtly employ CDKs that serve as key regulators of transcription (e.g., CDK9) for a continuous production of short-lived gene products that maintain their survival. As such, dysregulation of the CDK9 pathway has been observed in various hematological and solid malignancies, making it a valuable anticancer target. This therapeutic potential has been utilized for the discovery of CDK9 inhibitors, some of which have entered human clinical trials. This review provides a comprehensive discussion on the structure and biology of CDK9, its role in solid and hematological cancers, and an updated review of the available inhibitors currently being investigated in preclinical and clinical settings.

Potent and orally bioavailable CDK8 inhibitors: Design, synthesis, structure-activity relationship analysis and biological evaluation.

CDK8 regulates transcription either by phosphorylation of transcription factors or, as part of a four-subunit kinase module, through a reversible association of the kinase module with the Mediator complex, a highly conserved transcriptional coactivator. Deregulation of CDK8 has been found in various types of human cancer, while the role of CDK8 in supressing anti-cancer response of natural killer cells is being understood. Currently, CDK8-targeting cancer drugs are highly sought-after. Herein we detail the discovery of a series of novel pyridine-derived CDK8 inhibitors. Medicinal chemistry optimisation gave rise to 38 (AU1-100), a potent CDK8 inhibitor with oral bioavailability. The compound inhibited the proliferation of MV4-11 acute myeloid leukaemia cells with the kinase activity of cellular CDK8 dampened. No systemic toxicology was observed in the mice treated with 38. These results warrant further pre-clinical studies of 38 as an anti-cancer agent.

Targeting CDK2 in cancer: challenges and opportunities for therapy.

Cyclin-dependent kinase 2 (CDK2) plays a pivotal part in cell cycle regulation and is involved in a range of biological processes. CDK2 interacts with and phosphorylates proteins in pathways such as DNA damage, intracellular transport, protein degradation, signal transduction, DNA and RNA metabolism and translation. CDK2 and its regulatory subunits are deregulated in many human cancers and there is emerging evidence suggesting CDK2 inhibition elicits antitumor activity in a subset of tumors with defined genetic features. Previous CDK2 inhibitors were nonspecific and limited by off-target effects. The development of new-generation CDK2 inhibitors represents a therapeutic opportunity for CDK2-dependent cancers.

Validation of the Amharic Version of the Brief Fatigue Inventory for Assessment of Cancer-Related Fatigue in Ethiopian Cancer Patients.

BACKGROUND: Although cancer-related fatigue (CRF) is a highly prevalent and distressing symptom associated with cancer and its treatment, it is mostly underscreened, underassessed, and undertreated. The Brief Fatigue Inventory (BFI) is a reliable and valid instrument to assess CRF. OBJECTIVE: To validate the Amharic version of the BFI (BFI-Am) for assessment of CRF in Ethiopian cancer patients. METHODS: The BFI-Am was developed from its original English version through standard forward-backward translation approach. Two hundred eight consented cancer patients filled the questionnaires, along with the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-C30, version 3. In addition, sociodemographic and clinical information were collected. Psychometric properties of the BFI-Am were evaluated in terms of acceptability, internal consistency, construct validity, concurrent validity, and known group validity. Linear regression analysis was performed to identify possible predictors of fatigue severity. RESULTS: Two hundred two cancer patients completed the questionnaires and included in the data analysis. The BFI-Am had an overall Cronbach's alpha of 0.97. The results of the principal axis factor analysis suggested a one-factor solution explaining 78.4% of the variance, supporting the hypothesis of unidimensionality of the BFI-Am. The global BFI-Am interference items score was highly correlated with fatigue subscale score of European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-C30 than single items, showing an inverse correlation between the BFI-Am and the global health status/quality of life (r = -0.324; P = 0.000). The BFI-Am significantly detected the differences in fatigue severity in patients with poor performance status (P < 0.001), indicating known group validity. CONCLUSION: The BFI-Am is an excellent assessment tool with adequate psychometric properties for use in both clinical management and symptom research of CRF in Ethiopian cancer patients.

Validation of the Amharic Version of the M. D. Anderson Symptom Inventory and Assessment of Symptoms in Ethiopian Cancer Patients.

CONTEXT: Cancer patients often face a variety of symptoms that impact their quality of life. The management of these symptoms is highly dependent on the accurate appraisal of their severity through the use of a standardized symptom assessment tool. The M. D. Anderson Symptom Inventory (MDASI), developed in English, is one of such tools that contain 13 core cancer related symptoms that can easily be rated on a scale of 0-10. OBJECTIVES: The present study tried to develop and validate the Amharic language version of the MDASI (MDASI-Am). METHODS: The MDASI-Am was developed by the standard forward/backward translation of the original English version of the MDASI. The MDASI-Am was completed by or administered to 145 randomly selected Ethiopian cancer patients. Factor analysis, Cronbach α coefficient, and mean comparison, respectively, were used to establish construct validity, internal consistency, and known-group validity (Eastern Cooperative Oncology Group Performance Status). RESULTS: Factor analysis identified three symptom constructs interpreted as general, gastrointestinal, and neuropsychiatric symptoms, with Cronbach α coefficients of 0.70, 0.80, and 0.82, respectively. The MDASI-Am significantly detected differences in symptom severity and interference levels in patient groups categorized according to Eastern Cooperative Oncology Group Performance Status (P < 0.01), establishing known-group validity. The most prevalent severe symptoms identified in the current sample were pain, sadness, numbness, distress, and fatigue. CONCLUSION: The MDASI-Am is a valid and reliable tool for measuring symptom severity and symptom interference with daily living in Ethiopian cancer patients.