Efficacy and safety of tirbanibulin 1% ointment in actinic keratoses: Data from two phase-III trials and the real-life clinical practice presented at the European Academy of Dermatology and Venereology Congress 2022

BACKGROUND

The 31st European Academy of Dermatology and Venereology (EADV) Congress took place between 7th and 10th of September 2022 in Milan, Italy.

OBJECTIVES

We report presented clinical data on the efficacy/effectiveness, safety and tolerability of tirbanibulin 1% ointment that has recently been licensed for actinic keratosis (AK) of the face or scalp in adults.

METHODS

Summary of presentations given at the EADV Congress.

RESULTS

Prof. Pellacani presented two post hoc analyses from two phase-III trials with AK patients (NCT03285477 [N = 351] and NCT03285490 [N = 351]): A descriptive analysis of medical history, concomitant medications, and safety results confirming a favourable profile for tirbanibulin showing that number of baseline AK lesions was not correlated to severity of local skin reactions. The latter analysis showed that cases of tirbanibulin application site pain or pruritus were few, and most were found to be mild. Prof. Kunstfeld reported six real-life clinical cases in Austria showing good tirbanibulin effectiveness, safety and tolerability for the treatment of new or recurring AK lesions. Results demonstrated that after 2- to 4-month follow-up, tirbanibulin was well tolerated and effective in AK patients. Presentations by Dr. Patel confirmed good outcomes and tolerability of tirbanibulin in Olsen grade 1-2 AK (N = 12) and porokeratosis patients (N = 4) treated once daily for 5 consecutive days in the United Kingdom. Furthermore, real-world experience in solid organ transplant recipients (N = 2) demonstrated effectiveness of tirbanibulin in skin field cancerization treatment. A symposium sponsored by Almirall was conducted during the congress in which Dr. Hadshiew and Dr. Lear brought together their clinical experience in Germany and the United Kingdom respectively. Interesting clinical cases of 5 consecutive days of tirbanibulin treatment compared to other treatments were discussed with attendees, as well as current treatment needs of AK patients.

CONCLUSIONS

This article provides an overview of presentations and symposium discussions, summarizing key phase-III results and real-life clinical experience with tirbanibulin shared by dermatologists across Europe.

Human basal cell carcinoma: the induction of anagen hair follicle differentiation

BACKGROUND

Consistent with cancer stem cell driven pattern of growth, human basal cell carcinomas (BCCs) demonstrate differentiation along hair follicle (HF) lineages.

AIM

To define the pattern of differentiation and therapeutic targets that promote BCC differentiation and therefore BCC cancer stem cell exhaustion.

METHODS

An alkaline phosphatase substrate kit was used to determine dermal papilla cells within the BCC stroma. Autonomous HF cycle-dependent gene expression was identified by analysis of the human homologues of a murine gene set (total 2289 genes) that is differentially expressed in hair cycle phases. The findings were validated by quantitative real-time PCR and immunofluorescence, as well as in vitro transforming growth factor (TGF)-β2 stimulation of BCC cancer stem cell colonies.

RESULTS

As in the HF, keratin expression in the inner root sheath and matrix in BCC correlated with proliferative index and was tightly regulated, despite the absence of dermal papilla cells. Cross-species microarray analysis comparing human BCC and murine synchronous HF growth cycle datasets revealed 74% concordance with telogen differentiation compared with anagen (23%, P < 0.01) and catagen (49%; P < 0.01). Incomplete anagen differentiation within BCC was characterized by reduced expression of the anagen master regulator DLX3 (-5.5-fold), and increased expression of telogen-associated genes: AEBP1 (2.2-fold), DEFB8 (35.3-fold), MMP3 (106.0-fold) and MMP12 (12.9-fold). Restoration of dermal papilla signals by in vitro addition of TGF-β2 enhanced anagen differentiation.

CONCLUSION

Our findings show that BCC cells differentiate along HF lineages and may be susceptible to exogenous HF cycle modulators.

Abstract 2609: A novel MYB-AR cross-talk promoting castration-resistance in prostate cancer

Progression of prostate cancer from castration-sensitive to castration-resistant disease is a complex process, which likely involves multiple genetic and epigenetic alterations. Here we report a novel mechanism where MYB acts as a novel binding partner of AR enabling its ligand-independent activation to support castration resistance in prostate cancer. MYB and AR interact and co-localize with each other predominantly in the nuclei. Androgen-depletion or enzalutamide treatment does not interfere with MYB-AR interaction, and MYB-overexpressing prostate cancer cells retain AR in the nucleus even when cultured under androgen-deprived condition. Transcriptional activity of KLK3 (an androgen-responsive gene encoding PSA) promoter is increased in MYB-overexpressing cells, while sustained under androgen-depleted condition. In silico analysis identifies a MYB-binding region in KLK3 promoter in close proximity to the AR binding site, and MYB is shown to cooperatively promote AR binding to the KLK3 promoter. MYB-overexpressing prostate cancer cells exhibit greater tumorigenicity when implanted orthotopically and quickly regain growth following castration leading to the poorer survival of mice, compared to those carrying low MYB-expressing prostate tumors. Together, these findings establish a novel and significant role of MYB-AR cross-talk in prostate cancer, which could be exploited for its therapeutic management.

Citation Format: Sanjeev Kumar Srivastava, Haseeb Zubair, Girijesh K. Patel, Mohammad Aslam Khan, Sachin Kumar Deshmukh, Seema Sing, Joel Andrews, Bin Wang, James E. Carter, Ajay Pratap Singh. A novel MYB-AR cross-talk promoting castration-resistance in prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2609.

Abstract 1911: Bi-directional cross-talk of pancreatic cancer and stellate cells, mediated through CXCR4 and hedgehog pathways, promotes chemoresistance via its effect on gemcitabine metabolism, ROS detoxification and cancer stemness

Mounting evidence suggests that tumor-stromal interactions play a key role in pancreatic cancer (PC) pathogenesis and chemoresistance. We previously demonstrated that CXCL12, a chemokine secreted by activated pancreatic stellate cells (PSCs), promoted PC chemoresistance upon binding to its receptor CXCR4. Furthermore, activation of CXCL12/CXCR4 pathway in PC cells (PCCs) also increased the expression and secretion of sonic hedgehog (SHH), which is a known inducer of PSCs thus establishing a bi-directional tumor-stromal crosstalk. Here we present data to support that dual targeting of CXCL12/CXCR4 and hedgehog pathways is effective in improving therapeutic outcome in PC by diminishing multiple chemoresistance mechanisms. Monoculture of PCCs (MiaPaCa and Colo357) or coculture of PCCs and PSCs were treated with gemcitabine in the presence and absence of CXCR4 antagonist (AMD3100) and hedgehog inhibitor (GDC-0449). The data demonstrated that PCCs in coculture had better survival against gemcitabine treatment as compared to those grown in monoculture and inhibition of CXCL12/CXCR4 and hedgehog pathways abrogated this co-culture-induced chemoresistance. In further mechanistic studies, we identified co-culture-induced changes in gene expression and confirmed their functional significance in chemoresistance. Our data established important roles of genes associated with gemcitabine metabolism, ROS detoxification and stemness in PC chemoresistance. Inhibition of CXCL12/CXCR4 and hedgehog pathways led to increase in gemcitabine-mediated ROS production, enhanced accumulation of active gemcitabine metabolite (gemcitabine tri-phosphate) and reduced stemness in cocultured PCCs. Finally, we examined the efficacy of our dual targeting approach in vivo in an orthotopic mouse model of pancreatic cancer by treating the mice with gemcitabine alone or in combination with AMD3100 and/or GDC-0449. Our data demonstrated that mice treated with gemcitabine along with AMD3100 and/or GDC-0449 had significantly greater reduction in tumor growth as compared to those treated with gemcitabine only. Studies are ongoing in additional pancreatic tumor models. Together, these findings provide strong evidence in support of a novel combination therapy for pancreatic cancer treatment.

Citation Format: Mohammad Aslam Khan, Girijesh K. Patel, Sanjeev K. Srivastava, Sumit Arora, Haseeb Zubair, James Elliot Carter, Bin Wang, Seema Singh, Moh’d Khushman, Ajay P. Singh. Bi-directional cross-talk of pancreatic cancer and stellate cells, mediated through CXCR4 and hedgehog pathways, promotes chemoresistance via its effect on gemcitabine metabolism, ROS detoxification and cancer stemness [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1911.

Exosomal markers (CD63 and CD9) expression using immunohistochemistry (IHC) in patients with right-sided and left-sided colon cancer

e15119

Background: Embryologically, the right colon (cecum, ascending colon, hepatic flexure and proximal two-thirds of the transverse colon) is derived from the midgut, whereas the left colon (sigmoid colon, descending colon, splenic flexure and distal third of the transverse colon) is derived from the hindgut. There are clinical, pathological and molecular differences between patients with right-sided colon cancer (RSCC) and left-sided colon cancer (LSCC). Exosomes mediate intercellular communications and interactions and have pivotal roles in cancer behavior. CD63 and CD9 are widely accepted exosomal markers. Here we explored CD63 and CD9 expression using immunohistochemistry (IHC) in patients with RSCC and LSCC. Methods: Between 2015 and 2018, 63 patients underwent colon surgical resection for whom we had available tissues for CD63 and CD9 IHC staining. Two pathologists independently scored CD63 and CD9 expression in the tumor and adjacent normal mucosa (ANM). Staining intensity was graded from 1-3. Staining percentage was estimated in 10% increments. Mean quick-score (Q-score) was calculated (intensity x percentage). Unpaired t test was used for statistical analysis. Results: Median age was 64 (range 33-78). Females represented 60% of our cohort. Caucasians, African Americans and other Ethnicities represented 55%, 40% and 5% respectively. The sidedness was designated as RSCC in 52% and as LSCC in 48%. The ANM and Tumor CD63 Q scores were 225 vs 191 (p = 0.009) in RSCC and 224 vs 154 (p = 0.0001) in LSCC respectively. The ANM and Tumor CD9 Q scores are 134 vs 152 (p = 0.142) in RSCC and 135 vs 154 (p = 0.137) in LSCC respectively. In patients with RSCC and LSCC, the mean Tumor CD63 Q score is 191 vs 154 (p = 0.024), while the mean ANM CD63 Q score is 225 vs 224 (p = 0.920). The mean Tumor CD9 Q score is 152 and 154 (p = 0.883) and the mean ANM CD9 Q score is 134 vs 135 (p = 0.926). Conclusions: In our cohort of patients with RSCC and LSCC, the exosomal marker CD63 expression is lower in the tumor compared to the ANM. While ANM CD63 expression was similar between RSCC and LSCC, tumor CD63 expression was higher in RSCC compared to LSCC. The exosomal marker CD9 was not found to have significant differential expression between ANM and tumor and between RSCC and LSCC. To our knowledge, this is the first study to explore exosomal markers expression using IHC in patients with RSCC and LSCC.

Germline pharmacogenomics of thymidylate synthase gene in patients with gastrointestinal malignancies treated with fluoropyrimidines-based chemotherapy regimens

545

Background: Fluoropyrimidines are antimetabolites that target the S phase of the cell cycle. The active metabolite, 5-fluorodeoxyuridine monophosphate inhibits thymidylate synthase (TS) enzyme, thus preventing DNA synthesis and ultimately cell death. While controversy exists in the literature, polymorphism in the promoter region of thymidylate synthase gene (TYMS) that decrease TS expression has been associated with increased fluoropyrimidines-associated toxicities. This study explored the association between polymorphism in the promoter region of TYMS gene and fluoropyrimidines-associated toxicities in patients with gastrointestinal malignancies with mixed racial background. Methods: Between 2011 and 2018, 126 patients were genotyped for TYMS. Patients with known high-risk dihydropyrimidine dehydrogenase gene variants were excluded. Fluoropyrimidines-associated toxicity was graded according to the National Cancer Institiute Common Terminology Criteria for Adverse Events (v 5.0). Fisher’s exact test was used for statistical analysis. Results: TYMS genotypes that predict increased TS expression (3RG/3RG, 3RG/3RC, 2R/3RG, 2R/4R, 3R/4R, 4R/3RG) were identified in 55 patients (44%). TYMS genotypes that predict decreased TS expression (2R/2R, 2R/3RC, 3RC/3RC) were seen in 71 patients (56%). Among patients with genotypes that predict increased TS expression (N = 55), 12 patients had grade 3-4 toxicity (22%) while among patients with genotypes that predict decreased TS expression, 30 patients had grade 3-4 toxicities (42%) (P = 0.0219). Compared to patients with genotypes predicting increased TS expression, 17 out of 31 patients (55%) with 2R/2R TYMS genotype had grade 3-4 toxicity (P = 0.0039) and 15 out 40 patients (38%) with 2R/3RC and 3RC/3RC TYMS genotype had grade 3-4 toxicity (P = 0.1108). Among patients with 2R/2R TYMS, Caucasians represented 61% and African Americans represented 39%. Females represented 65% of the patients. Conclusions: Polymorphism in the promoter region of TYMS gene that predict decreased TS expression due to 2R/2R variant was associated with grade 3-4 fluoropyrimidines-associated toxicities.

The correlation between DPYD*9A (c.85T > C) genotype and dihydropyrimidine dehydrogenase deficiency phenotype in patients with gastrointestinal malignancies treated with fluoropyrimidines: Updated analysis

544

Background: The correlation between DPYD*9A (c.85T > C) genotype and dihydropyrimidine dehydrogenase (DPD) deficiency phenotype is controversial. In our cohort of 28 patients with gastrointestinal malignancies (GI) treated with fluoropyrimidines, DPYD*9A was the most commonly diagnosed variant (46%) and there was a noticeable genotype-phenotype correlation (Khushman et al). In this updated analysis, a larger cohort of a mixed racial background was genotyped for DPYD*9A variant to confirm the incidence and genotype-phenotype correlation. Methods: Between 2011 and 2018, in addition to genotyping for high risk DPYD variants (DPYD*2A, DPYD*13 and DPYD*9B), genotyping for DPYD*9A variant was performed on 113 patients. Fluoropyrimidines-associated toxicity was graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events (v 5.0). Results: DPYD variants were identified in 61 patients. DPYD*2A was identified in 3 patients and DPYD*9B was identified in 2 patients (one patient had double heterozygous *9A and *9B). Heterozygous DPYD*9A was identified in 46 patients (41%) and homozygous DPYD*9A was identified in 11 patients (10%). Among patients with DPYD*9A variant, Caucasians represented 51% and African Americans represented 46%. 27 patients (47%) were females. Grade 3-4 toxicities were experienced in 26 patients with mutant DPYD*9A (3 patients had homozygous DPYD*9A) and in 20 patients with no identified DPYD mutation (P = 0.7035). In patients who received full dose fluoropyrimidines (N = 85), grade 3-4 toxicities were experienced in 22 patients with mutant DPYD*9A (2 patients had homozygous DPYD*9A) and in 17 patients with no identified DPYD mutation (P = 0.8275). Conclusions: In our updated analysis, DPYD*9A variant was the most commonly diagnosed variant. The correlation between DPYD*9A variant and DPD clinical phenotype was not reproduced. The noticeable correlation that we previously reported is likely due to small sample size and patients’ selection and testing bias.

Germline pharmacogenomics of DPYD*9A (c.85T>C) variant in patients with gastrointestinal malignancies treated with fluoropyrimidines

598

Background: The correlation between DPYD*9A (c.85T > C) genotype and dihydropyrimidine dehydrogenase (DPD) deficiency clinical phenotype is controversial. Reference laboratories either did not perform DPYD*9A genotyping or have stopped DPYD*9A genotyping and limited genotyping to high-risk variants (DPYD*2A, DPYD*13 and DPYD*9B) only. This study explored DPYD*9A genotype and clinical phenotype correlation in patients with gastrointestinal (GI) malignancies treated with fluoropyrimidines. Methods: Between 2011 and 2017, 67 patients with GI malignancies were genotyped for DPYD variants. Fluoropyrimidines-associated toxicity was graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events (version 3.0). Fisher’s exact test was used for statistical analysis. Results: DPYD variants were identified in 17 out of 67 (25%) patients. One patient was homozygous for DPYD*9A variant and one patient was double heterozygous for DPYD*9A and DPYD*9B variants. 13/17 (76%) patients had DPYD*9A variant, 3/17 (18%) patients had DPYD*2A variant and 2/17 (12%) patient had DPYD*9B variant. Only patients genotyped prior to 2015 were genotyped for DPYD*9A variant (N = 28). Of those, 13/28 patients (46%) had DPYD*9A variant. Grade 3-4 diarrhea was associated with DPYD*9A variant in patients treated with full dose fluoropyrimidines (P = 0.0055). Conclusions: In our cohort, DPYD*9A variant was the most common diagnosed variant. The correlation between DPYD*9A genotype and DPD deficiency clinical phenotype was noticeable in patients who received full dose fluoropyrimidines as they all experienced grade 3-4 toxicities (diarrhea).

The prognostic significance of exosomal markers (CD63 and CD9) expression using immunohistochemistry in patients with pancreatic ductal adenocarcinoma

342

Background: Exosomes are important mediators of intercellular communications and play pivotal roles in cancer progression, metastasis and chemoresistance. CD63 and CD9 are exosomal markers. In patients with pancreatic ductal adenocarcinoma (PDAC), positive correlation between CD9 expression and overall survival (OS) was reported. CD63 expression was conserved in all patients with no reported prognostic significance. This study explored the prognostic significance of CD63 and CD9 expression using immunohistochemistry (IHC) in patients with PDAC of mixed racial background. Methods: Between 2012 and 2016, 49 patients with PDAC had available tissues for CD63 and CD9 staining using IHC. Two pathologists independently scored CD63 and CD9 expression. Staining intensity was graded from 1-3. Staining percentage was estimated in 10% increments. Mean Quick-score (Intensity X Percentage of staining) was calculated. Results: Median age was 64 (range 42-85). 53% are males. 67% Caucasians, 27% African Americans (AA) and 6% are other ethnicities. 41% had stage IV while 59% had stage I-III. The mean CD63 and CD9 Q scores are higher in primary tumor from the pancreas compared to pancreatic tumor from metastatic sites (185 vs 102, p = 0.0002) and (48 vs 11, p = 0.0418) respectively. We fitted accelerated failure-time models to investigate the impacts of the covariates CD63 and CD9 on progression free survival (PFS) and OS. CD63 has significant impact on PFS (p = 0.0058) and OS (p = 0.0012). The higher the CD63 Q score, the longer the PFS and OS. CD9 doesn’t have significant impact on PFS (p = 0.8950) or OS (p = 0.7182). The mean CD63 and CD9 Q scores are slightly higher in AA compared to Caucasians (157 vs 149, p = 0.76) and (45 vs 29, p = 0.43) respectively. Conclusions: CD63 and CD9 expression is higher in primary tumor from the pancreas compared to pancreatic tumor from metastatic sites. There is correlation between CD63 expression (but not CD9 in this cohort) and PFS and OS. To our knowledge, this is the first study to show prognostic significance of CD63 expression in patients with PDAC using IHC. A trend of higher expression of CD63 and CD9 among AA compared to Caucasians was noticed.

A case of neofunctionalization of a Putranjiva roxburghii PNP protein to trypsin inhibitor by disruption of PNP-UDP domain through an insert containing inhibitory site

The attainment of new function by a protein is achieved through convergent/divergent evolution. In present work, the sequence analysis of a 34kDa protein from Putranjiva roxburghii, earlier reported as a potent trypsin inhibitor, showed resemblance to some of the wound inducible and vegetative storage proteins. A detailed sequence analysis revealed that these proteins belong to PNP-UDP family. In case of P. roxburghii protein, an approximately 46 residue insert disrupts the PNP domain. Similar disruption of PNP domain is observed in related plant proteins. The characterization of recombinant full length and truncated (without 46 residue insert) forms of P. roxburghii PNP family protein (PRpnp) unraveled that trypsin inhibitory active site is located within the insert. The truncated form containing uninterrupted PNP domain showed strong PNP enzymatic activity where it hydrolyzed the N-glycosidic bond of inosine and guanosine. The full length protein, however, showed weak PNP enzyme activity which may be due to presence of the insert. These results indicate towards the neofunctionalization of PRpnp to a potent trypsin inhibitor through an insert containing inhibitory residue to cater to the needs of plant defense. The similar wound inducible and vegetative storage proteins may have also evolved due to evolutionary needs.

The prognostic significance of exosomal marker (CD63) expression using immunohistochemistry (IHC) in patients with pancreatic ductal adenocarcinoma (PDAC)

e15730

Background: Exosomes are important mediators of intercellular communication, and play pivotal roles in cancer progression, metastasis and chemoresistance. Exosomal membranes are enriched in endosomes-specific tetraspanins (CD63 and CD9). In patients with PDAC, positive correlation between CD9 expression and overall survival (OS) was reported. However, CD63 expression was conserved in all patients without reported prognostic significance. Here, we explored the prognostic significance of CD63 expression using IHC in patients with PDAC of mixed gender and racial background. Methods: Between 2012 and 2016, 49 patients with PDAC treated at Mitchell Cancer Institute had available tissue (pancreatic resected tissue/biopsy [N = 29] or metastatic site biopsy liver, omentum or bone (N = 20)) for CD63 staining using IHC. Two pathologists independently scored the expression of CD63. Staining intensity was graded from 1-3. Staining percentage was estimated in 10% increments. Mean Quick-score (Intensity X Percentage of staining) was calculated. Unpaired t test was used for statistical analysis. Results: Median age was 64 years (range 42-85). 53% are males. 67% white, 27% African Americans (AA) and 6% are other ethnicities. 41% had stage IV disease while 49% had stage I, II and III. Tumor involved the head (51%), body (20%) and tail (29%). The mean CD63 Q score is slightly higher in AA compared to white (157 vs 149, P = 0.76). The mean CD63 Q score is higher in the pancreatic tissues compared to metastatic sites tissues (185 Vs 102, P = 0.0002). In our cohort, patients with mean CD63 Q score > = 140 had longer median OS compared to patients with mean Q score of < 140 (19 months Vs 3 months, P = 0.0003) and progression free survival (PFS) (12 months vs 1 month, P = 0.0043). Conclusions: In our cohort of patients with PDAC, there was no racial difference in CD63 expression between white and AA. The expression of CD63 is higher in the pancreas compared to metastatic sites (liver, omentum and bone). There is positive correlation between CD63 expression and PFS and OS. To our knowledge, this is the first study to show prognostic significance of CD63 expression in patients with PDAC using IHC.

Platelet Rich Fibrin in Management of Complex Endoperio Cases

Endo-perio lesions have been a dilemma to the dental practitioner. Both tissues share the same anatomical origin. Sometimes exact etiological passage of disease process cannot be traced; nevertheless traditional and newer treatment modalities must be employed to ensure best treatment possibilities. Patient reported with pain and pus exudates in upper left anterior region. Past dental history revealed no history of trauma. Initial examination revealed draining sinus with respect to 22. However, no Caries and pockets could be detected. Tooth was nonresponsive to vitality test. Patient symptoms did not relieve even two months after completion of RCT. Apical surgery was planned. Apicectomy was done and osseous defect was filled with PRF coagulum. Patient was followed up every three months and showed complete resolution of all symptoms. Radiographs showed complete resolution of osseous defect in nine months. PRF can be used to enhance bone augmentation in treatment of periapical defects as a potential treatment alternative for faster healing.

Abstract 2799: Exosomes from hypoxic pancreatic cancer cells confer resistance to subsequent hypoxia insult

Pancreatic cancer (PC) remains one of the leading causes of cancer-associated deaths in the US due to its highly aggressive nature and lack of effective treatments. Pancreatic tumors are characterized by a dense, desmoplastic reaction and poor vasculature leading to reduced oxygen levels within the tumor microenvironment. It is believed that this encounter of pancreatic tumor cells to intratumoral hypoxic condition is a major cause of their persistent survival under a variety of stresses, increased aggressiveness and therapeutic-resistance. However, underlying molecular mechanisms responsible for PC's adaptation to hypoxia (along with enhanced growth and aggressiveness) remain elusive. In this study, we examined the role of exosomes, which are nanoscale biological vesicles with a lipid bilayer membrane, in imparting survival benefit to PC cells. For this, we first examined the effect of conditioned media (CM) from PC cells cultured under hypoxic (0.1% O2, H-CM) or normoxic (21% O2, N-CM) conditions on the growth of fresh PC cells cultured under hypoxic (0.1% O2) conditions. We found that H-CM conferred significant survival benefit to cancer cells under hypoxia as compared to N-CM. Thereafter, we isolated exosomes from N-CM (N-exo) or H-CM (H-exo) and used them to treat pancreatic cancer cells under hypoxic culture conditions. We observed that H-exo imparted a significantly higher survival advantage to cancer cells under hypoxia as compared to N-exo. Interestingly, protein quantification indicated the presence of higher levels of exosomes from cells cultured under hypoxic conditions as compared to those grown in normoxic environment. Western blot analysis with anti-CD9 and anti-CD63 antibodies confirmed enrichment of exosomes. Moreover, Dynamic Light Scattering-based size distribution suggested that H-exo were smaller in size compared to N-exo. Further studies are underway to identify the molecular determinants in exosomes responsible for inducing growth-promoting effects under hypoxia. Overall, our data provides the first evidence that hypoxic PC cells secrete exosomes that enhance survivability under hypoxic conditions.

Citation Format: Mary C. Patton, Haseeb Zubair, Girijesh K. Patel, Seema Singh, Ajay P. Singh. Exosomes from hypoxic pancreatic cancer cells confer resistance to subsequent hypoxia insult. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2799.

Abstract 2116: Chemotherapy-induced exosomal secretion promotes chemoresistance in pancreatic cancer cells

Introduction: Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of death from cancer in the United States, with a dismal median survival rate of 2-8 months after diagnosis and a 5-year overall survival rate of ∼7%. It carries a notoriously poor prognosis due to advanced stage at presentation for most patients, lack of very effective therapy and development of resistance to available chemotherapy. Intercellular communication between tumor-tumor and tumor-nontumor cells is critical for tumor growth and progression. Extracellular vesicles (EVs) comprising of exosomes, microvesicles and apoptotic bodies are considered important mediators of intercellular communication and play pivotal roles in different physiological and pathological processes. However, role of EVs in the development of acquired resistance to chemotherapy in PDAC cells is largely unexplored. Here, we examined the role of EVs in chemotherapeutic resistance of PDAC cells.

Methods: Conditioned media from vehicle-treated and (V-CM) gemcitabine-treated PDAC cells (Gem-CM) were collected and fractionated into soluble (Gem-Sol) and vesicular (GEM-EV) factions. PDAC cells were pre-treated with Gem-CM, Gem-Sol and Gem-EV followed by treatment with various doses (0-20 μM) of gemcitabine for different time intervals (48 and 72 h). EVs were then separated by differential ultracentrifugation, size was determined using Dynamic Light Scattering (DLS) and assessed for their chemoresistance conferring activity in PDAC cells. Immunoblotting was performed to examine the specific markers associated with EVs.

Results: Both Gem-CM and Gem-EV provided significant protection to gemcitabine-treated cells, while Gem-Sol had only negligible effect. DLS based-size distribution analysis identified EVs of three different size viz. large (&gt; 1500 nm), medium (500-1500 nm) and small (100-300 nm). Treatment of large and medium sized Gem-EVs did not show any chemoprotective effect in PDAC cells, while smaller Gem-EVs provided remarkable survival benefits to PDAC cells against gemcitabine treatment. Immunoblot data revealed that these active EVs are enriched with CD9 and CD63, specific markers of exosomes. Interestingly, we observed that exosomes of gemcitabine-treated PDAC cells were larger than those secreted by vehicle treated cells. Moreover, the amount of exosomes in Gem-CM was significantly higher as comparison to the CM of vehicle-treated cells. Studies are being conducted to identify the cargo encapsulated by exosomes responsible for exosomes-mediated chemoresistance in PDAC cells.

Conclusion: Our findings suggest that chemotherapy induces secretion of exosomes in PDAC cells that enhances chemoresistance by spreading the molecular signals.

Citation Format: Girijesh K. Patel, Arun Bhardwaj, Sanjeev K. Srivastava, Mohammad Aslam Khan, Seema Singh, Moh’d Khushman, Ajay P. Singh. Chemotherapy-induced exosomal secretion promotes chemoresistance in pancreatic cancer cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2116.

Successful treatment of pyoderma gangrenosum with topical 0.5% nicotine cream

Pyoderma gangrenosum is potentially a devastating and destructive disorder. There is no uniformly effective or specific therapy for pyoderma gangrenosum. Previous reports of nicotine therapy for pyoderma gangrenosum have suggested it to be efficacious. Unfortunately, previous reports were restricted by the use of commercially available preparations of nicotine, either as a gum or patch formulation. We have used topical nicotine 0.5% w/w cetamacrogol formula A cream that enables direct application onto the lesion, as well as dose and concentration variation. Two patients with pyoderma gangrenosum treated with topical nicotine 0.5% w/w cetamacrogol formula A cream are described here, both of whom had dramatic clinical resolution of their pyoderma gangrenosum.

Staphylococcus aureus re-colonization in atopic dermatitis: beyond the skin

Patients with atopic dermatitis (AD) are often heavily colonized by Staphylococcus aureus, which adversely affects eczema severity. Strategies to control S. aureus in AD include antibiotic and or antiseptics. However long-term efficacy is unclear. In this study we consider extra-cutaneous factors that may cause S. aureus re-colonization in adult AD. Twenty-one patients with AD were recruited and were assessed for: duration of AD, use of topical or oral antibiotic within the preceding 3 months, the number of hospital admissions during the preceding year and current treatment. The types of topical treatments used, vehicle, container and the expiry dates were also recorded. The severity of AD was assessed by SCORAD index. Microbiological assessment for S. aureus carriage from affected skin, anterior nares, emollient and topical steroid was undertaken using culture, Staphaurex test and antibiotic resistance. Of the patients 86% had S. aureus colonization. The median SCORAD score were greater in those colonized with S. aureus (P = 0.02) and those with contaminated treatments (P = 0.05). Prior antibiotic treatment, prior hospital admission and nasal carriage did not influence the median SCORAD. Three extra-cutaneous mechanisms by which S. aureus can re-colonize the skin were identified: antibiotic resistance, nasal carriage and treatment contamination.

Wound-related osteomyelitis: a case of containment not cure

Community nurses need to be aware that some patients with osteomyelitis are treated with antibiotics alone. Such patients often have co-morbidities and quality of life issues that directly impact on the decision to treat osteomyelitis surgically. However, adopting a conservative approach to osteomyelitis management is associated with an increased risk of osteomyelitis recurrence. The rationale for managing chronic wound-related osteomyelitis with antibiotics is discussed. Community nurses caring for patients that have received antibiotics alone to treat osteomyelitis need to be aware of the potential for osteomyelitis recurrence and how to make the diagnosis.

Intestinal bypass syndrome presenting as erythema nodosum

Intestinal bypass was a popular surgical procedure for morbid obesity resulting, on average, in a 50 kg weight loss. We describe a 66-year-old woman who underwent the procedure 12 years earlier and subsequently presented with recurrent episodes of erythema nodosum-like lesions. Further investigations revealed hyperoxaluria, renal failure, deficiency of fat-soluble vitamins (causing night blindness, osteomalacia and easy bruising) and anaemia. Antibiotics led to only temporary remission and, as with 24-30% of similar cases, she underwent surgical reversal to prevent the complications from worsening.

An aggressive treatment for aggressive digital papillary adenocarcinoma

Aggressive digital papillary adenoma (ADPA) and adenocarcinoma (ADPAca) are adnexal tumors that are not often recognized because of their rarity. We present a rare case of ADPAca involving the left middle finger of a 43-year-old man. Histopathological features of ADPAca are distinct from those of other eccrine sweat gland tumors; however, ADPAca may be misdiagnosed particularly for a metastasis of papillary adenocarcinoma originating in the colon, thyroid, or breast. Clinicopathological correlation is essential to ule out a possible risk of metastatic carcinoma of the skin. Recognition of these tumors is important because of a potential risk of local recurrence nd distant metastases. Aggressive surgical treatment consisting of digit amputation is advocated in the treatment of ADPAca.

Science, medicine and the future: healing chronic wounds

Greater interest in wound healing is needed to ensure higher standards of basic care. Precise identification of the systemic, local, and molecular factors underlying the wound healing problem in individual patients should allow better tailored treatment. Allogeneic skin grafting and bioengineered skin equivalents are being used successfully in patients with venous leg ulcers and diabetic patients with foot ulcers.

Managing gravitational eczema and allergic contact dermatitis

Venous leg ulceration is a common chronic problem in the community, and gravitational eczema is a common complication of it. The presence of gravitational eczema can lead to further ulceration and may also impair wound healing. Treatment often requires more than one topical preparation, to gain control and prevent relapse. Knowledge of the benefits and risks of these therapeutic modalities is essential, in this article we aim to provide a practical approach to the treatment of gravitational eczema. We also discuss allergic contact dermatitis, a common complication of gravitational eczema.

Rifampicin-induced lupus erythematosus

Rifampicin has been prescribed throughout the world for over 20 years, yet only four cases of rifampicin-induced lupus erythematosus (LE) have been reported. Rifampicin-induced LE is associated with combination therapy with clarithromycin or ciprofloxacin. These drugs are all metabolized through the cytochrome P450 liver enzyme system and combined usage may lead to higher rifampicin blood levels. Drug-induced LE differs from systemic LE; cutaneous manifestations, although uncommon, are an important clue to the diagnosis. We report a case of rifampicin-induced LE presenting with florid cutaneous features.

Klippel-Trenaunay syndrome: what are the implications for wound care?

Patients with Klippel-Trenaunay syndrome may present with problems such as allergic contact dermatitis and ulceration. This case study explains how it should be diagnosed and treated.

Malignant atrophic papulosis (Degos' disease): clinicopathological correlations

Malignant atrophic papulosis (MAP) is a rare disease characterized by pathognomonic cutaneous lesions and frequently fatal systemic involvement. Dermatologists should have a high index of suspicion for systemic complications in a patient presenting with MAP. We report a case of malignant atrophic papulosis to highlight the clinicopathological features and review this important dermatological diagnosis.

Severe digital necrosis in an elderly patient with heterozygous factor V Leiden mutation

We report an 81-year-old female with a heterozygous factor V Leiden mutation who developed purpura fulminans. Digital necrosis, a characteristic clinical feature of purpura fulminans was prominent. Purpura fulminans is more common in children and adult cases are rare. Of eight reported cases of purpura fulminans resulting from a heterozygous factor V Leiden mutation recorded in the literature, only two were in adults: 40 and 42 years of age, respectively. This is the first report of this condition arising in a patient in her eighties.

An unusual case of purpuric erythropoietic protoporphyria

Erythropoietic protoporphyria (EPP) is the most common of the erythropoietic porphyrias. Recent advances in diagnostic laboratory tests have led to the discovery of a number of previously undiagnosed cases. We describe a case of EPP presenting late with a purpuric eruption and discuss the pathogenesis and significance of purpura in EPP.

A complex photodermatosis: solar urticaria progressing to polymorphic light eruption

We report an unusual case of localized solar urticaria which progressed on each occasion to polymorphic light eruption (PLE); this was initially noted following provocation by narrow band ultraviolet B (311-313 nm) phototherapy.

Chloroplast targeting ofneomycin phosphotransferase II with a pea transit peptide in electroporated barley mesophyll protoplasts

Routine methods for stable gene transfer to cereals are not yet available. To be able to study chloroplast targeting in barley (Hordeum vulgare L.) cells, the expression of recombinant genes was assayed in barley mesophyll protoplasts after electroporation of DNA. The CaMV 35S transcript promoter was attached to a chimeric gene consisting of a pea RuBisCo small subunit transit peptide coding sequence (tp) and the gene coding for neomycin phosphotransferase II (nptII). As a control, a construction with no transit peptide coding segment was used. 48 hours after electroporation, a fraction of the protoplasts was lysed and intact chloroplasts were isolated. Protoplasts electroporated with either of the gene constructions showed strong NPTII activity. However, enzyme activity was detected in chloroplasts only when thetp-nptII gene construction was used. Protease treatment of the chloroplasts confirms that the pea RuBisCo small subunit transit peptide is targeting the NPTII polypeptide into the chloroplasts, subsequent to the synthesis of the hybrid precursor in barley cells.

Mechanisms of gastroesophageal reflux in patients with reflux esophagitis

We evaluated the mechanisms of gastroesophageal reflux in 10 patients with reflux esophagitis and compared the results with findings from 10 controls. The patients had more episodes of reflux (35 +/- 15 in 12 hours, as compared with 9 +/- 8 in the controls) and a lower pressure of the lower esophageal sphincter (13 +/- 8 mm Hg as compared with 29 +/- 9 in the controls) (P less than 0.001). Reflux occurred by three different mechanisms: transient complete relaxation of the lower esophageal sphincter, a transient increase in intra-abdominal pressure, or spontaneous free reflux associated with a low resting pressure of the lower esophageal sphincter. In controls 94 per cent of reflux episodes were caused by transient sphincter sphincter relaxation. In the patients 65 per cent of episodes of reflux accompanied transient sphincter relaxation, 17 per cent accompanied a transient increase in intra-abdominal pressure, and 18 per cent occurred as spontaneous free reflux. The predominant reflux mechanism in individual patients varied: some had normal resting sphincter pressure and reflux that occurred primarily during transient sphincter relaxation, whereas others with low resting sphincter pressures had spontaneous free reflux or reflux that occurred during an increase in intra-abdominal pressure.

Extended and limited types of Barrett's esophagus in the adult

Columnar epithelium-lined lower esophagus (CLLE) or Barrett's esophagus was found in 34 patients diagnosed by endoscopic biopsy. In one-half of them, the CLLE extended up to 30 cm from the incisors (limited group) and in the other half, it reached above this level (extended group). Eight patients with stricture and limited CLLE had the lesion in the lower third of the esophagus, whereas 6 of 8 with strictures in the extended group had narrowing in the upper third of the esophagus. Two other patients with extended CLLE were seen with bleeding from Barrett's ulcer, 3 had adenocarcinoma, and the remaining 4 had CLLE without these complications. The three classic histologic types were encountered in both groups. However, in the extended group there was more of the intestinal type and less of the junctional type of epithelium, the latter being seen mostly in the limited group. The extended group had very low lower esophageal sphincter (LES) pressures (mean, 7.3 mm Hg) with severe reflux. The limited group had a higher mean LES pressure (11.2 mm Hg) with less severe reflux. In both groups, LES pressure and reflux improved following effective antireflux operation; some patients who continued to have demonstrable reflux and a lack of improvement in LES pressure despite antireflux operation, the disease progressed, as evidenced by extension of CLLE.

Granular cell myoblastoma of the esophagus. Report of two cases

Granular cell myoblastoma (GCM) of the esophagus is a rare, usually benign tumor, most often discovered incidentally during upper endoscopy, surgery, or autopsy. Although some reports have questioned the safety of endoscopic biopsy of granular cell tumors of the esophagus, we feel that the procedure can be performed safely and accurately. For the unwary, histological examination may lead to a misdiagnosis of squamous cell carcinoma. Although some reports of malignant esophageal tumors can be found, in general, if the histologic appearance of the tumor is benign, malignant transformation or metastasis is unusual. Surgical resection for malignant and for large symptomatic benign tumors is the treatment of choice. In, however, individuals with histologically benign tumors. who are asymptomatic or who are not considered good surgical candidates, careful observation with endoscopic follow-up can be safely done.

Glucagon effects on the human small intestine

In healthy volunteers, the effects of intravenously administered glucagon on small intestinal function was investigated. Bolus doses resulting in plasma glucagon concentrations of greater than 800 pg/ml (5 min after injection) abolished jejunal contractions for 4.4 +/- 0.4 (SEM) min after a latency period of 49 +/- 4 sec. During continuous intravenous glucagon infusion, jejunal dilatation and increase in mean transit time (MTT) occurred at plasma levels greater than 720 pg/ml, while inhibition of water and electrolyte absorption was observed only with plasma glucagon concentrations of 1760 +/- 114 pg/ml. Under these conditions, the propulsion of fasting intestinal contents was slowed without change in flow rate. The observed effects cannot be attributed to the simultaneously occurring rise in plasma insulin and glucose concentrations. Short-term increases in circulating glucagon concentration inhibit intestinal tone, contractions, and propulsion with only a minor effect on water and electrolyte absorption limited to a narrow concentration range of plasma glucagon. Neither effect occurs at glucagon levels likely to occur under physiologic concentrations. The latency period preceding the abolition of jejunal contractions suggests that glucagon does not act directly on intestinal smooth muscle cells.