Craig D. Logsdon

KRAS mutations are prevalent in patients with pancreatic ductal adenocarcinoma (PDAC) and are critical to fostering tumor growth in part by aberrantly rewiring glucose, amino acid, and lipid metabolism. Obesity is a modifiable risk factor for pancreatic cancer. Corroborating this epidemiological observation, mice harboring mutant KRAS are highly vulnerable to obesogenic high-fat diet (HFD) challenges leading to the development of PDAC with high penetrance. However, the contributions of other macronutrient diets, such as diets rich in carbohydrates that are regarded as a more direct source to fuel glycolysis for cancer cell survival and proliferation than HFD, to pancreatic tumorigenesis remain unclear. In this study, we compared the differential effects of a high-carbohydrate diet (HCD), an HFD, and a high-protein diet (HPD) in PDAC development using a mouse model expressing an endogenous level of mutant KRAS^G12D specifically in pancreatic acinar cells. Our study showed that although with a lower tumorigenic capacity than chronic HFD, chronic HCD promoted acinar-to-ductal metaplasia (ADM) and pancreatic intraepithelial neoplasia (PanIN) lesions with increased inflammation, fibrosis, and cell proliferation compared to the normal diet (ND) in Kras^G12D/+ mice. By contrast, chronic HPD showed no significant adverse effects compared to the ND. Furthermore, ablation of pancreatic acinar cell cyclooxygenase 2 (Cox-2) in Kras^G12D/+ mice abrogated the adverse effects induced by HCD, suggesting that diet-induced pancreatic inflammation is critical for promoting oncogenic KRAS-mediated neoplasia. These results indicate that diets rich in different macronutrients have differential effects on pancreatic tumorigenesis in which the ensuing inflammation exacerbates the process. Management of macronutrient intake aimed at thwarting inflammation is thus an important preventive strategy for patients harboring oncogenic KRAS.

The aim of the present study was to investigate the effects of a non-steroidal anti-inflammatory drug (NSAID), naproxen, on a spontaneous mouse model of lung adenocarcinoma. Lung cancer is the most frequently diagnosed cancer and the primary cause of cancer-related deaths worldwide. Inflammation plays an important role in the development and progression of lung and several other cancers. The association between NSAID use and lung cancer risk suggests a beneficial effect on patients’ lung cancer progression. Preventing lung cancer can help to significantly reduce cancer-related mortality. Compared with other NSAIDs, naproxen is relatively safer in terms of cardiovascular risk. Eight-week-old transgenic Kras^G12V male and female mice (n=20) or littermate wild-type (n=5) mice were fed (AIN76A) diets containing naproxen (0 ppm or 400 ppm) in modified AIN76-A diet for 28 weeks. At 36 weeks of age, mice were euthanized. Lungs were collected and evaluated for lung tumor incidence and multiplicity, and were saved in formalin for histopathological identification of adenoma and adenocarcinoma. By 12 weeks of age, Kras^G12V mice developed visible lung tumors that enlarged in size and progressed to adenocarcinoma by 24-36 weeks of age. Lung tumor incidence was observed in 100% of Kras^G12V mice. Dietary administration of naproxen did not show any overt-toxicities. No significant changes were observed in body weight gain or any major organ’s (liver, kidney, and pancreas) gross morphology or weight in mice fed with naproxen compared with mice fed control diet. Due to reduced tumor burden, lungs of the naproxen-fed mice weighed less (230.6± 12.2 mg, p=0.019) (Mean±SEM) than those of the control group (384.0±68.1 mg). Importantly, mice fed control diet developed 19.8±0.96 total lung tumors (2.5±0.3 adenoma, 17.3±0.7 adenocarcinoma). The results suggest that naproxen inhibits total lung tumor formation by ~52% (9.4±0.85;ppCitation Format: Gaurav Kumar, Venkateshwar Madka, Craig Logsdon, Anil Singh, Nicole Stratton, Stanley Lightfoot, Altaf Mohammed, Chinthalapally V. Rao. Naproxen blocks spontaneous lung adenoma progression to adenocarcinoma in Kras-^G12V mice [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 5075.

Cancer is one of the most complex diseases that has resulted in multiple genetic disorders and cellular abnormalities. Globally, cancer is the most common health concern disease that is affecting human beings. Great efforts have been made over the past decades in biology with the aim of searching novel and more efficient tools in therapy. Thus, small interfering RNAs (siRNAs) have been considered one of the most noteworthy developments which are able to regulate gene expression following a process known as RNA interference (RNAi). RNAi is a post-transcriptional mechanism that involves the inhibition of gene expression through promoting cleavage on a specific area of a target messenger RNA (mRNA). This technology has shown promising therapeutic results for a good number of diseases, especially in cancer. However, siRNA therapeutics have to face important drawbacks in therapy including stability and successful siRNA delivery in vivo. In this regard, the development of effective siRNA delivery systems has helped addressing these issues by opening novel therapeutic windows which have allowed to build up important advances in Nanomedicine. In this review, we discuss the progress of siRNA therapy as well as its medical application via nanoparticle-mediated delivery for cancer treatment.

Metastatic disease is the leading cause of death among cancer patients and involves a complex and inefficient process. Every step of the metastatic process can be rate limiting and is influenced by non-malignant host cells interacting with the tumor cell. Over a century ago, experiments first indicated a link between the immune system and metastasis. This phenomenon, called concomitant immunity, indicates that the primary tumor induces an immune response, which may not be sufficient to destroy the primary tumor, but prevents the growth of a secondary tumor or metastases. Since that time, many different immune cells have been shown to play a role in both inhibiting and promoting metastatic disease. Here we review classic and new observations, describing the links between the immune system and metastasis that inform the development of cancer therapies.