Development of polymeric drug delivery vehicles for targeted cancer therapy

The aim of my Ph. D. thesis is to generalize a method for targeted anti-cancer drug delivery. Hydrophilic polymer-drug conjugates involve complicated synthesis; drug-encapsulated polymeric nanoparticles limit the loading capability of payloads. This thesis introduces the concept of nanoconjugates to overcome difficulties in synthesis and formulation. Drugs with hydroxyl group are able to initiate polyester synthesis in a regio- and chemo- selective way, with the mediation of ligand-tunable Zinc catalyst. Herein, three anti-cancer drugs are presented to demonstrate the high efficiency and selectivity in the method (Chapter 2-4). The obtained particles are stable in salt solution, releasing drugs over weeks in controlled manner. With the conjugation of aptamer, particles are capable to target prostate cancer cells in vitro. These results open the gateway to evaluate the in vivo efficacy of nanoconjugates for target cancer therapy (Chapter 5). Mechanism study of the polymerization leads to the discovery of chemosite selective synthesis of prodrugs with acrylate functional groups. Functional copolymer-drug conjugates will expand the scope of nanoconjugates (Chapter 6). Liposome-aptamer targeting drug delivery vehicle is well studied to achieve reversible cell-specific delivery of non-hydoxyl drugs e.g. cisplatin (Chapter 7). New monomers and polymerization mechanisms are explored for polyester in order to synthesize nanoconjugates with variety on properties (Chapter 8). Initial efforts to apply this type of prodrugs will be focused on the preparation of hydrogels for stem cell research (Chapter 9).

Clinical and molecular characterization of feline mammary carcinomas overexpressing HER2 proto-oncogene (FMC-HER2+) : new strategies for effective diagnostic and cancer therapy

Tese de Doutoramento em Ciências Veterinárias na Especialidade de Ciências Biológicas e Biomédicas

Spatially defined peptidomimetics for pain relief and for targeted cancer therapy and diagnostics

Cancer is a disease that has plagued scientists for decades, and how to treat cancer and its complications are inevitable topics in current scientific research. Cancer pain is a major factor that reduces the quality of life of patients. Therefore, the development of analgesic agents with minimal adverse side effects, especially with low addiction, has attracted more and more attention. Among them, opioid analgesics are widely used to alleviate cancer pain and improve the quality of life of patients with advanced cancer, such as in the palliative therapy. Although peptide drugs are efficient, selective and safe, they have several unignorable disadvantages such as poor biological stability, rapid excretion, difficulty in penetrate blood brain barrier. In order to solve these problems, peptidomimetics were developed by introducing unnatural/modified amino acids, decorated peptide backbone, conformational restrictions and secondary structure mimics in peptide sequence. Compared with peptides, peptidomimetics have improved biological stability, increased bioavailability, high affinity and selectivity for receptor binding, and decreased adverse side effects. As the second part of this thesis, I explored the opportunity to design peptide-functionalized responsive biomaterials for the detection of cancer cell and the selective delivery of cytotoxic drugs. The conjugation of peptides with biomaterials enhanced the stability of the loaded drugs, improved targeted delivery, decreased side effects, and increased bioavailability. The precise and controllable drug delivery platform has profound application prospects in cancer treatment. Grafting specific peptides sequence on the surface of biomaterials can satisfy different drug delivery demands according to the characteristics of both peptides and biomaterials. For example, the introduction of tumor-targeting peptides can guide biomaterials into tumor lesions, and blood-brain barrier (BBB) shuttle peptides can lead biomaterials to penetrate the BBB, etc.

Female melanoma: the role of ovarian stimulation and antioestrogens cancer therapy A retrospective study with immunohistochemical oestrogen receptors alpha and beta analysis.

Cutaneous melanoma (CM) represents the third most common cancer in Italian women under 49 years old. In the last decades, many molecular studies confirmed that sex hormones have a part in melanogenesis and melanoma genesis. However, many controversies are present regarding the role of exogenous oestrogens intake and endogenous hormonal status in female melanoma. Our study's primary objective is to investigate the features of melanoma in women of fertile age and women in postmenopausal age. The secondary aim is to evaluate the expression of ERα and ERβ by immunohistochemical analysis in women who underwent ovarian stimulation for medically assisted procreation and in women in cancer therapy for breast cancer (BC) comparing to two control groups. The tertiary objective is to correlate ERα and ERβ with the Breslow thickness and other relevant histopathological, clinical and dermoscopic characteristics Results A total of 998 women were included in the study. Women in fertile age are significantly more prone to have CM on the trunk. Conversely, postmenopausal females are more likely to develop CM on acral locations. Breslow thickness and ulceration were statistically significant among postmenopausal women (P-value <0,001). In the group for women with a history of breast cancer (BC), we observed a significantly higher CM percentage with “non-brisk” TILs. Upon immunohistochemical analysis, most cases with inhibitor aromatase therapy displayed a strong cytoplasmatic ERα positivity. Upon the Pearson correlation analysis, no association was shown between nuclear ERβ and Breslow thickness. The meaning of cytoplasmatic ERα in melanoma is still debated. It could suggest a potentially significant role of oestrogen non-genomic pathway in these patients, or it can be a mechanism of ERs modulation in response to aromatase inhibitor therapy. Our work tried to enlighten some of the existing shadows on the role of ERs and hormonal factors in CM.

Photophysical studies and in vitro skin permeation/retention of Foscan (R)/nanoemulsion (NE) applicable to photodynamic therapy skin cancer treatment.

In this work we evaluated the photophysical and in vitro properties of Foscan (R), a second-generation photosensitizer drug (PS) widely used in systemic clinical protocols for cancer therapy based on Photodynamic Therapy (PDT). We employed biodegradable nanoemulsions (NE) as a colloidal vehicle of the oil/water (o/w) type focusing in topical administration of Foscan (R) and other photosensitizer drugs. This formulation was obtained and stabilized by the methodology described by Tabosa do Egito et al.,(30) based on the mixture of two phases: an aqueous solution and an organic medium consisting of nonionic surfactants and oil. The photodynamic potential of the drug incorporated into the NE was studied by steady-state and time-resolved spectroscopic techniques. We also analyzed the in vitro biological behavior carried out in mimetic biological environment protocols based on the animal model. After topical application in a skin animal model, we evaluated the Foscan (R)/NE diffusion flux into the skin layers (stratum corneum and epidermis + dermis) by classical procedures using Franz Diffusion cells. Our results showed that the photophysical properties of PS were maintained after its incorporation into the NE when compared with homogeneous organic medium. The in vitro assays enabled the determination of an adequate profile for the interaction of this system in the different skin layers, with an ideal time lag of 6 h after topical administration in the skin model. The Foscan (R) diffusion flux (J) was increased when this PS was incorporated into the NE, if compared with its flux in physiological medium. These parameters demonstrated that the NE can be potentially applied as a drug delivery system (DDS) for Foscan (R) in both in vitro and in vivo assays, as well as in future clinical applications involving topical skin cancer PDT.

Cancer theranostics: multifunctional gold nanoparticles for diagnostics and therapy

Doctorate in Biology, Specialty in Biotechnology

Low-dose angiostatic tyrosine kinase inhibitors improve photodynamic therapy for cancer: lack of vascular normalization.

Photodynamic therapy (PDT) is an effective clinical treatment for a number of different cancers. PDT can induce hypoxia and inflammation, pro-angiogenic side effects, which may counteract its angio-occlusive mechanism. The combination of PDT with anti-angiogenic drugs offers a possibility for improved anti-tumour outcome. We used two tumour models to test the effects of the clinically approved angiostatic tyrosine kinase inhibitors sunitinib, sorafenib and axitinib in combination with PDT, and compared these results with the effects of bevacizumab, the anti-VEGF antibody, for the improvement of PDT. Best results were obtained from the combination of PDT and low-dose axitinib or sorafenib. Molecular analysis by PCR revealed that PDT in combination with axitinib suppressed VEGFR-2 expression in tumour vasculature. Treatment with bevacizumab, although effective as monotherapy, did not improve PDT outcome. In order to test for tumour vessel normalization effects, axitinib was also applied prior to PDT. The absence of improved PDT outcome in these experiments, as well as the lack of increased oxygenation in axitinib-treated tumours, suggests that vascular normalization did not occur. The current data imply that there is a future for certain anti-angiogenic agents to further improve the efficacy of photodynamic anti-cancer therapy.

Stratum corneum lipids liposomes for the topical delivery of 5-aminolevulinic acid in photodynamic therapy of skin cancer: preparation and in vitro permeation study

Abstract Background Photodynamic therapy (PDT) using 5-aminolevulinic acid (5-ALA) is a skin cancer therapy that still has limitations due to the low penetration of this drug into the skin. We have proposed in this work a delivery system for 5-ALA based on liposomes having lipid composition similar to the mammalian stratum corneum (SCLLs) in order to optimize its skin delivery in Photodynamic Therapy (PDT) of skin cancers. Methods SCLLs were obtained by reverse phase evaporation technique and size distribution of the vesicles was determinated by photon correlation spectroscopy. In vitro permeation profile was characterized using hairless mouse skin mounted in modified Franz diffusion cell. Results Size exclusion chromatography on gel filtration confirmed vesicle formation. SCLLs obtained by presented a degree of encapsulation of 5-ALA around 5.7%. A distribution of vesicle size centering at around 500 nm and 400 nm respectively for SCLLs and SCLLs containing 5-ALA was found. In vitro 5-ALA permeation study showed that SCLLs preparations presented higher skin retention significantly (p < 0.05) on the epidermis without SC + dermis, with a decreasing of skin permeation compared to aqueous solution. Conclusions The in vitro delivery performance provided by SCLLs lead to consider this systems adequate for the 5-ALA-PDT of skin cancer, since SCLLs have delivered 5-ALA to the target skin layers (viable epidermis + dermis) to be treated by topical PDT of skin cancer.

[11C]Choline PET/CT for targeted salvage lymph node dissection in patients with biochemical recurrence after primary curative therapy for prostate cancer. Preliminary results of a prospective study

INTRODUCTION: In this prospective study we set out to investigate the diagnostic value of [(11)C]choline-PET/CT in patients with suspected lymph node metastases before salvage lymph node dissection. PATIENTS AND METHODS: 15 consecutive patients with rising PSA underwent [(11)C]choline-PET/CT and consecutive open salvage pelvic/retroperitoneal extended lymph node dissection due to uptake of [(11)C]choline in at least 1 lymph node. Mean age was 62.1 (range 53-73). RESULTS: [(11)C]choline-PET/CT results were compared with the histopathology reports and clinical follow-up (mean 13.7 months, range 6-24). Mean time to progression was 23.6 months (range 4-81). [(11)C]choline uptake was observed in nodes along the external and internal and common iliac arteries and in the paraaortic region. A positive histology was reported in 8/15 patients. Only one patient had a PSA nadir of <0.1 ng/ml after salvage surgery. Another patient had stable disease with a PSA of 0.5 ng/ml. Three patients developed bone metastases during follow-up. CONCLUSIONS: This interim analysis indicates that [(11)C]choline-PET/CT may be a useful technique in detection of lymph node metastases when rising PSA occurs after definite prostate cancer therapy. The presented cohort is limited in size, but there is still strong evidence that the patients benefit from [(11)C]choline-PET/CT and consecutive salvage lymph node dissection is rather small.

A systematic review of personalized therapy in patients with advanced cancer

Background: An increased understanding of the pathogenesis of cancer at the molecular level has led to the development of personalized cancer therapy based on the mutation status of the tumor. Tailoring treatments to genetic signatures has improved treatment outcomes in patients with advanced cancer. We conducted a meta-analysis to provide a quantitative summary of the response to treatment on a phase I clinical trial matched to molecular aberration in patients with advanced solid tumors. ^ Methods: Original studies that reported the results of phase I clinical trials in patients with advanced cancer treated with matched anti-cancer therapies between January 2006 and November 2011 were identified through an extensive search of Medline, Embase, Web of Science and Cochrane Library databases. Odds Ratio (OR) with 95% confidence interval (CI) was estimated for each study to assess the strength of an association between objective response rate (ORR) and mutation status. Random effects model was used to estimate the pooled OR and their 95% CI was derived. Funnel plot was used to assess publication bias. ^ Results: Thirteen studies published between January 2006 and November 2011that reported on responses to matched phase I clinical trials in patients with advanced cancer were included in the meta-analysis. Nine studies reported on the responses seen in 538 of the 835 patients with driver mutations responsive to therapy and seven studies on the responses observed in 234 of the 306 patients with mutation predictive for negative response. Random effects model was used to estimate pooled OR, which was 7.767(95% CI = 4.199 − 14.366; p-value=0.000) in patients with activating mutations that were responsive to therapy and 0.287 (95% CI = 0.119 − 0.694; p-value=0.009) in patients with mutation predictive of negative response. ^ Conclusion: It is evident from the meta-analysis that somatic mutations present in tumor tissue of patients are predictive of responses to therapy in patients with advanced cancer in phase I setting. Plethora of research and growing evidence base indicate that selection of patients based on mutation analysis of the tumor and personalizing therapy is a step forward in the war against cancer.^

Study on the effect of metformin in patients of metastatic renal cell cancer with diabetes receiving tyrosine kinase inhibitor therapy

Objective: The primary objective of our study was to study the effect of metformin in patients of metastatic renal cell cancer (mRCC) and diabetes who are on treatment with frontline therapy of tyrosine kinase inhibitors. The effect of therapy was described in terms of overall survival and progression free survival. Comparisons were made between group of patients receiving metformin versus group of patients receiving insulin in diabetic patients of metastatic renal cancer on frontline therapy. Exploratory analyses were also done comparing non-diabetic patients of metastatic renal cell cancer receiving frontline therapy compared to diabetic patients of metastatic renal cell cancer receiving metformin therapy. ^ Methods: The study design is a retrospective case series to elaborate the response rate of frontline therapy in combination with metformin for mRCC patients with type 2 diabetes mellitus. The cohort was selected from a database, which was generated for assessing the effect of tyrosine kinase inhibitor therapy associated hypertension in metastatic renal cell cancer at MD Anderson Cancer Center. Patients who had been started on frontline therapy for metastatic renal cell carcinoma from all ethnic and racial backgrounds were selected for the study. The exclusion criteria would be of patients who took frontline therapy for less than 3 months or were lost to follow-up. Our exposure variable was treatment with metformin, which comprised of patients who took metformin for the treatment of type 2 diabetes at any time of diagnosis of metastatic renal cell carcinoma. The outcomes assessed were last available follow-up or date of death for the overall survival and date of progression of disease from their radiological reports for time to progression. The response rates were compared by covariates that are known to be strongly associated with renal cell cancer. ^ Results: For our primary analyses between the insulin and metformin group, there were 82 patients, out of which 50 took insulin therapy and 32 took metformin therapy for type 2 diabetes. For our exploratory analysis, we compared 32 diabetic patients on metformin to 146 non-diabetic patients, not on metformin. Baseline characteristics were compared among the population. The time from the start of treatment until the date of progression of renal cell cancer and date of death or last follow-up were estimated for survival analysis. ^ In our primary analyses, there was a significant difference in the time to progression of patients receiving metformin therapy vs insulin therapy, which was also seen in our exploratory analyses. The median time to progression in primary analyses was 1259 days (95% CI: 659-1832 days) in patients on metformin therapy compared to 540 days (95% CI: 350-894) in patients who were receiving insulin therapy (p=0.024). The median time to progression in exploratory analyses was 1259 days (95% CI: 659-1832 days) in patients on metformin therapy compared to 279 days (95% CI: 202-372 days) in non-diabetic group (p-value <0.0001). ^ The median overall survival was 1004 days in metformin group (95% CI: 761-1212 days) compared to 816 days (95%CI: 558-1405 days) in insulin group (p-value<0.91). For the exploratory analyses, the median overall survival was 1004 days in metformin group (95% CI: 761-1212 days) compared to 766 days (95%CI: 649-965 days) in the non-diabetic group (p-value<0.78). Metformin was observed to increase the progression free survival in both the primary and exploratory analyses (HR=0.52 in metformin Vs insulin group and HR=0.36 in metformin Vs non-diabetic group, respectively). ^ Conclusion: In laboratory studies and a few clinical studies metformin has been proven to have dual benefits in patients suffering from cancer and type 2-diabetes via its action on the mammalian target of Rapamycin pathway and effect in decreasing blood sugar by increasing the sensitivity of the insulin receptors to insulin. Several studies in breast cancer patients have documented a beneficial effect (quantified by pathological remission of cancer) of metformin use in patients taking treatment for breast cancer therapy. Combination of metformin therapy in patients taking frontline therapy for renal cell cancer may provide a significant benefit in prolonging the overall survival in patients with metastatic renal cell cancer and diabetes. ^

Nausea, Vomiting And Quality Of Life Of Patients With Cancer Undergoing Antineoplastic Treatment: An Evaluation By Pharmacists.

This study aims to evaluate the frequency and severity of nausea and vomiting using two different instruments and relate them to quality of life (QOL) in patients with cancer receiving antineoplastic treatment. Severity of chemotherapy-induced nausea and vomiting (CINV) was measured by Common Terminology Criteria for Adverse Events (CTCAE) and a numerical scale. QOL was assessed using the Functional Assessment of Cancer Therapy-General questionnaire. Of the 50 patients studied, 60.0% reported nausea (40.0% CTCAE grade 1; 66.7% moderate intensity on numerical scale) and 30.0% reported vomiting (46.7% CTCAE grades 1 and 2, each; 66.7% moderate intensity on numerical scale). CINV did not influence overall QOL. The frequency of CINV was high. There was no association between nausea/vomiting and overall QOL.