The Ridky Lab

Research Program: Multifunction Genetics in Human Tissue

Multi-Functional Genetics in Human Tissue (MFG-H) refers to the experimental capacity to alter function of multiple proteins and pathways simultaneously within 3-dimensionally intact human tissue. MFG-H is a versitile, rapid, and adaptable experimental platform designed to advance mechanistic biological studies more rapidly than classical genetic systems, in a medically-relevant human tissue context.  MFG-H developed out of a need to overcome technical limitations inherent to traditional experimental approaches for cancer research.

  1. The limited physiologic relevance of many commonly utilized experimental model systems to human biology and disease: Findings in conventional model systems frequently fail to translate into clinically useful progress in the treatment of human disease. Central to this failure are major limitations intrinsic to current experimental systems. Most human cancer studies utilize either transformed cell lines, or murine models as the starting substrate for functional studies. However, most cells lines have been selected for their ability to proliferate in long-term passage on 2-D plastic, rater than their ability to recapitulate the hallmark features of the malignancy from which they were initially derived.  Most of these lines have undergone genomic catastrophe and are aneuploid, rendering each cancer cell line unique in terms of genomic structure, gene regulation, signaling and biological behavior. Because of this, different cell lines (even from the same tissue type) often provide contradictory results. This has made extrapolation of data with cell lines to general biologic functional relationships and clinical meaningfulness problematic. It is also difficult to determine the effects of a specific tumor-associated genetic change when they are expressed within the "dirty" complex background of a cell line harboring its own complement of hundreds or even thousands of genetic alterations.  Purely murine studies using transgenic and knockout mice, while extremely powerful and genetically elegant, also suffer from substantial limitations.  Murine and human tissue differ in a host of ways, including oncoprotein signaling targets, carcinogen function and susceptibility to malignant transformation.  The transgenic animal platform also does not lend itself to the high-throughput experimentation, which is necessary to functionally interrogate the rapidly increasing numbers of genetic alterations identified in spontaneous tumors as the result of large-scale full genome sequencing efforts.
  2. The need to perform increasingly complex genetic experiments in which the function of multiple proteins and signaling networks is altered simultaneously within intact tissue.  This is a critical issue of particular importance to cancer biology as progression to cancer results from the progressive accumulation of multiple genetic events that ultimately synergize to drive tumor formation and subsequent metastasis.   In mice, altering function of 4 to 6 alleles represents a practical upper limit.  Generating such multi-allele mice can take many years, is financially expensive, and often fails due to a variety of technical limitations. The use of multiplex serial gene transfer (MSGT) using high efficiency retroviral or lentiviral gene transfer into primary human cells allows for complex genetic experiments in which the function of previously unattainable numbers of alleles are simultaneously altered within intact tissue in a matter of hours, in multiple combinations, across multiple tissue types in parallel, at minimal cost.
University of Pennsylvania | Perelman School of Medicine