Focus on Cancer RSS Feed 2015-03-16 16:14:00

March is Colorectal Cancer Awareness Month. To learn more about screening, symptoms, treatments and the latest research, we’re teaming up with 6ABC for a live, streaming web chat at 6abc.com/pennmedicine.

Colorectal Cancer – Did you know?

Colon Cancer Screening

Colorectal cancer, cancer of the colon and rectum, is the second leading cause of cancer deaths in the United States.

You may be at a higher risk for colorectal cancer as you get older, but with education and screening, you can help reduce your risk.

Screening Can Save Lives

For those 50 years and older, getting a colorectal cancer screening can be life saving.

Symptoms like the appearance of polyps in the colon or rectum, persistent stomach aches and pains, rapid weight loss and bloody bowel movements may be key indicators.

While these symptoms may be indicative of other ailments, colorectal cancer screenings can help you take the right next steps.

This March, Colorectal Cancer Awareness Month, be sure to ask the right questions, and get the facts.

Our Experts Answering Your Questions

Patients and loved ones can submit questions ahead of time and also watch the chat in full after our broadcast.

Want to know more about:

  • Colorectal cancer screening?
  • Risk evaluation?
  • Hereditary risk?
  • Cutting-edge treatment potions?
  • New breakthrough clinical trials?
  • Survivorship?

Please join Penn experts Gregory G. Ginsberg, MD, Timothy C. Hoops, MD and Joshua I.S. Bleier, MD on Thursday, March 19 2015 at 4pm. 

To submit your questions and set up an email reminder for the live web chat,
please visit 6abc.com/PennMedicine
.

Susceptibility to RSPO2 Defines Pancreatic Cancer Stem Cells

Cancer stem cells (CSC) present a formidable clinical challenge by escaping therapeutic intervention and seeding tumors through processes that remain incompletely understood. Here, we describe small subpopulations of pancreatic cancer cells with high intrinsic Wnt activity (Wnthigh) that possess properties indicative of CSCs, including drug resistance and tumor-initiating capacity, whereas cell populations with negligible Wnt activity (Wntlow) preferentially express markers of differentiation. Spontaneous response to extrinsic Wnt signals induces signaling networks comprising ERK1/2 and epithelial–mesenchymal transition that subsequently confer cancer stemness traits to susceptible cells. Wnt enhancer R-Spondin 2 (RSPO2) seems to play a prominent upstream role in regulating this interplay. In this context, Wnthigh cells were more likely to give rise to Wnthigh progeny, tended to be more metastatic, and revealed higher levels of RSPO2 expression. Our studies reveal adaptive aspects of pancreatic cancer stemness arising from driver populations of CSCs that misappropriate functional and responsive elements of archetypical self-renewal pathways. Blocking such stemness-promoting pathways in conjunction with established chemotherapy could provide means to disrupt dynamic CSC process and present novel therapeutic targets and strategies. Cancer Res; 75(9); 1–14. ©2015 AACR.

RSpo2 enhances canonical Wnt signaling to confer stemness-associated traits to susceptible pancreatic cancer cells

Cancer stem cells (CSCs) present a formidable clinical challenge by escaping therapeutic intervention and seeding tumors through processes that remain incompletely understood. Here, we describe small subpopulations of pancreatic cancer cells with high intrinsic Wnt activity (Wnthigh) that possess properties indicative of CSCs, including drug-resistance and tumor initiating capacity, while cell populations with negligible Wnt activity (Wntlow) preferentially express markers of differentiation. Spontaneous response to extrinsic Wnt signals induces signaling networks comprising ERK1/2 and epithelial-mesenchymal transition that subsequently confer cancer-stemness traits to susceptible cells. Wnt enhancer R-Spondin 2 (Rspo2) seems to play a prominent upstream role in regulating this interplay. In this context Wnthigh cells were more likely to give rise to Wnthigh progeny, tended to be more metastatic, and revealed higher levels of Rspo2 expression. Our studies reveal adaptive aspects of pancreatic cancer stemness arising from driver populations of CSCs that misappropriate functional and responsive elements of archetypical self-renewal pathways. Blocking such stemness-promoting pathways in conjunction with established chemotherapy could provide means to disrupt dynamic CSC process and present novel therapeutic targets and strategies.

Loss of VEGF Induces Melanoma Niche Morphogenesis

The basis for resistance to VEGF inhibition is not fully understood despite its clinical importance. In this study, we examined the adaptive response to VEGF-A inhibition by a loss-of-function analysis using plasmid-based shRNA. Tumor xenografts that initially responded to VEGF-A inhibition underwent an adaptation in vivo, leading to acquired resistance. VEGF-A blockade in tumors was associated with HIF1α expression and an increase in CD144+ vasculogenic mimicry (VM), leading to formation of channels displaying Tie-1 and MMP-2 upregulation. CD133+ and CD271+ melanoma stem-like cells (MSLC) accumulated in the perivascular niche. Tumor xenografts of melanoma cell populations that were intrinsically resistant to VEGF-A blockade did not exhibit any of these features, compared with nontarget control counterparts. Thus, melanomas that are initially sensitive to VEGF-A blockade acquire adaptive resistance by adopting VM as an alternate angiogenic strategy, thereby enriching for deposition of MSLC in the perivascular niche through an HIF1α-dependent process. Conversely, melanomas that are intrinsically resistant to VEGF-A blockade do not show any evidence of compensatory survival mechanisms that promote MSLC accumulation. Our work highlights the potential risk of anti-VEGF treatments owing to a selective pressure for an adaptive resistance mechanism that empowers the development of stem-like cancer cells, with implications for how to design combination therapies that can improve outcomes in patients. Cancer Res; 75(8); 1–9. ©2015 AACR.

Induction of vasculogenic mimicry overrides VEGF-A silencing and enriches stem-like cancer cells in melanoma

The basis for resistance to VEGF inhibition is not fully understood despite its clinical importance. In this study, we examined the adaptive response to VEGF-A inhibition by a loss-of-function analysis using plasmid-based shRNA. Tumor xenografts that initially responded to VEGF-A inhibition underwent an adaptation in vivo leading to acquired resistance. VEGF-A blockade in tumors was associated with HIF-1α expression and an increase in CD144+ vasculogenic mimicry (VM), leading to formation of channels displaying Tie-1 and MMP-2 upregulation. CD133+ and CD271+ melanoma stem-like cells (MSLC) accumulated in the perivascular niche. Tumor xenografts of melanoma cell populations that were intrinsically resistant to VEGF-A blockade did not exhibit any of these features, compared to non-target control counterparts. Thus, melanomas which are initially sensitive to VEGF-A blockade acquire adaptive resistance by adopting VM as an alternate angiogenic strategy, thereby enriching for deposition of MSLC in the perivascular niche through a HIF-1α-dependent process. Conversely, melanomas which are intrinsically resistant to VEGF-A blockade do not show any evidence of compensatory survival mechanisms that promote MSLC accumulation. Our work highlights the potential risk of anti-VEGF treatments owing to a selective pressure for an adaptive resistance mechanism that empowers the development of stem-like cancer cells, with implications for how to design combination therapies that can improve outcomes in patients.